Fact-checked by Grok 2 weeks ago

Astragalus

Astragalus is a genus of flowering plants in the legume family Fabaceae, comprising approximately 3,000 species of annual and perennial herbs and small shrubs, making it the largest genus of vascular plants worldwide.^[1] The genus is primarily distributed across temperate regions of the Northern Hemisphere, with major centers of diversity in southwest Asia (around 2,000 species) and the Sino-Himalayan region (about 400 species), as well as significant representation in North America and Europe.^[2] Species typically inhabit dry to moist habitats such as grasslands, shrublands, and mountainous areas, often on sandy or rocky soils, and many are adapted to arid conditions.^[3] Common names include milkvetch (reflecting their resemblance to vetch plants and occasional use as livestock fodder) and locoweed (for certain toxic species that cause neurological disorders in grazing animals due to alkaloids like swainsonine).^[3] Among the most notable species is Astragalus membranaceus (commonly known as huang qi or milkvetch root), a perennial herb native to Mongolia, China, and Korea, where it grows up to 150 cm tall with pinnately compound leaves and yellow flowers blooming from June to August.^[4] For over 2,000 years, the dried root of A. membranaceus has been a cornerstone of traditional Chinese medicine, documented as early as the Shennong Bencao Jing (Han Dynasty), to tonify qi (vital energy), strengthen the spleen and lungs, promote diuresis, reduce swelling, and treat conditions such as fatigue, edema, chronic wounds, and immune deficiencies.^[4] In modern pharmacology, extracts from A. membranaceus have been extensively studied for their rich content of over 200 bioactive compounds, including polysaccharides, saponins (e.g., astragaloside IV), and isoflavonoids (e.g., calycosin and formononetin), which demonstrate immunomodulatory, antioxidant, anti-inflammatory, cardioprotective, and potential anti-aging effects through pathways like NF-κB inhibition and PI3K/Akt activation.^[4]^[5] While many Astragalus species contribute to ecological roles as nitrogen-fixers in soils and as pollinator resources, some North American taxa are rare endemics threatened by habitat loss, underscoring the genus's biodiversity conservation importance.^[6]

Description

Morphology

Astragalus species exhibit a diverse range of growth habits, predominantly as perennial herbs or subshrubs, though some are annuals or larger shrubs, often featuring erect, ascending, prostrate, or stemless forms that can reach heights of 1-2 meters in taller species.^[7] These plants are typically glabrous or covered in basifixed or medifixed hairs that may be white, black, or glandular, with stems arising from a root crown and sometimes developing spines in arid-adapted taxa.^[7] The leaves of Astragalus are alternate and compound, usually pinnate with 3-25 elliptic to obovate leaflets that are entire or serrately edged, measuring several centimeters in length; stipules are often adnate to the petiole and may be distinct or basally connate.^[7] In cushion-forming species adapted to harsh environments, leaves can be reduced to small, scale-like structures, enhancing drought tolerance.^[8] Flowers are characteristic papilionaceous types arranged in axillary racemes that are pedunculate and bear 1 to many blooms, with caducous or persistent bracts and bracteoles. The corolla, ranging from white and yellow to purple or pink, comprises an ovate to obovate standard, oblong wings (auriculate or not), and a spirally incurved keel; the campanulate calyx has five subequal or unequal teeth, while the diadelphous stamens surround a glabrous style ending in a small stigma.^[7] Fruits develop as stipitate or sessile legumes that are cylindrical, globose, or inflated, straight to curved, and glabrous to hairy, often featuring adaptations such as hairs or spines to aid dispersal; these pods contain 1 to many reniform seeds that are smooth or rugose.^[7] Many species produce inflated or leathery pods that split at maturity to release seeds passively.^[9] The root system in most Astragalus species consists of a deep taproot, often branching laterally a short distance below the crown and extending several meters into the soil, which facilitates water access in arid habitats.^[10] This structure supports adaptive radiation into dry, hostile microenvironments.^[8]

Reproduction

Astragalus species primarily reproduce sexually through hermaphroditic flowers arranged in racemose inflorescences that develop sequentially from axillary buds, with pollination leading to fertilization and seed set in legumes.^[11] Many species, such as A. filipes, are self-compatible and capable of autogamy, producing viable seeds without external pollinators, but they exhibit significantly higher seed set—up to ninefold—through outcrossing, which enhances genetic diversity and reproductive success.^[11] In A. argaeus, for instance, manual self-pollination yields fruit set rates of about 70%, while cross-pollination increases it to 90%, indicating a mixed mating system that favors xenogamy when pollinators are available.^[12] Fertilization occurs via pollen tube growth through the style to the ovules in the monocarpellate ovary, resulting in 10–30 seeds per pod depending on species and environmental conditions.^[11] Pollination in Astragalus is predominantly entomophilous, with bees serving as the primary vectors across the genus; specialist solitary bees like those in the genus Osmia and Hoplitis are common, alongside generalist bumblebees (Bombus spp.) and honeybees (Apis mellifera).^[11] In A. filipes, Osmia bruneri accounts for over 40% of pollinator visits, facilitating effective cross-pollination through sonication or buzz pollination on the poricidal anthers.^[11] Some species display bee-pollination syndromes, including ultraviolet-reflective nectar guides on the banner petal that direct pollinators to the nectar reward at the base of the corolla tube, as observed in A. cibarius and A. eriocarpus.^[13] These adaptations promote outcrossing by encouraging repeated visits from foraging insects, though self-pollination can occur if pollinator activity is low.^[13] Seed production follows successful pollination, with maturing pods varying in dehiscence mechanisms: many species exhibit passive indehiscence, retaining seeds until external disturbance, while others, like certain subgenus Astragalus members, show explosive dehiscence driven by tension in the lignified septum and valve margins.^[14] Seed viability is high in fresh pods, often exceeding 90% post-treatment, but physical dormancy imposed by the impermeable seed coat necessitates scarification for germination; mechanical abrasion or sulfuric acid immersion (30–40 minutes) breaks this dormancy, achieving 94–100% germination rates at optimal temperatures of 20–25°C.^[15] In A. arpilobus, an annual ephemeral, scarified seeds germinate rapidly in autumn or spring under fluctuating temperatures (e.g., 20/10°C), with viability persisting in soil seed banks for multiple seasons due to incomplete dormancy release.^[16] Asexual reproduction occurs in select species through vegetative means, such as rhizomatous growth or root suckering, allowing clonal propagation in stable habitats. Astragalus canadensis, a rhizomatous perennial, spreads via oblique or horizontal rhizomes that produce new shoots, enabling colony formation without sexual reproduction.^[17] Similarly, A. arenarius relies heavily on clonal reproduction via root suckers in fragmented populations, where sexual seed set is low (less than 10% of ramets produce seeds), contributing to population persistence at range edges.^[18] These mechanisms are less common across the genus, which is dominated by sexual reproduction, but they provide resilience in disturbed or pollinator-limited environments. The life cycle of Astragalus species varies by habit, with most being herbaceous perennials that progress from seed germination to maturity over 1–3 years, though about 120 annual species complete their cycle in one growing season. In perennials like A. membranaceus var. mongholicus, seedlings emerge in early spring (April), establishing leaves and roots within 10–20 days before stem elongation and flowering by mid-summer, culminating in seed maturation and entry into dormancy by autumn.^[19] Annuals, such as A. arpilobus, germinate post-rain in desert ephemerals, rapidly developing inflorescences within weeks, setting seed, and senescing before summer drought, with ungerminated seeds entering physiological and physical dormancy to survive unfavorable periods.^[16] Some perennials exhibit whole-plant dormancy, skipping above-ground growth in dry years while maintaining below-ground reserves for future reproduction.

Taxonomy

Classification

Astragalus belongs to the family Fabaceae, subfamily Faboideae, and tribe Astragaleae (formerly Galegeae).^[20] The genus encompasses over 3,000 species of herbs and shrubs, rendering it one of the largest genera within Fabaceae and among all flowering plants (3,095 accepted species as of 2025).^[21]^[1] Infrageneric divisions include subgenera such as Astragalus, Epiglottis, and Cercidothrix, which help organize the extensive diversity based on morphological and molecular traits.^[22] Phylogenetic analyses utilizing nuclear ribosomal internal transcribed spacer (ITS) sequences and chloroplast DNA regions, such as the trnL intron, have supported the monophyly of Astragalus as a whole while revealing polyphyly in certain subgroups, indicating complex evolutionary histories and potential need for taxonomic revisions. Recent clade-specific phylogenomic studies (as of 2025) continue to refine the backbone phylogeny, confirming high diversification rates since the Middle Miocene.^[23]^[24] These molecular studies complement earlier morphological classifications, highlighting convergent traits across lineages.^[25] Seminal revisions, particularly those by Rupert C. Barneby in his 1964 Atlas of North American Astragalus and the 1989 treatment in the Intermountain Flora, established foundational frameworks for North American taxa by delineating species boundaries and sectional groupings based on pod morphology and floral features.^[26] Barneby's work emphasized the genus's variability, influencing subsequent global classifications.^[27] Infrageneric classification primarily occurs at the sectional level, with over 250 sections recognized worldwide; examples include Sect. Astragalus, characterized by cylindrical pods, and Sect. Leptalei, distinguished by slender, elongated pods.^[28] Delimitation of these sections relies on pod structure—such as shape, valve texture, and dehiscence—as well as chromosome numbers, which vary from diploid (2n=16) to hexaploid (2n=48), reflecting polyploidy and base numbers of x=8 in Old World lineages and x=11–15 in New World ones.^[29] These cytological and morphological criteria aid in resolving relationships within the genus.^[30] Synonymy challenges persist due to historical taxonomic mergers and splits, often driven by overlapping traits; for instance, the genus Oxytropis was separated from Astragalus primarily based on keel petal morphology (porrect beak in Oxytropis versus blunt in Astragalus), despite ongoing debates about their close phylogenetic ties within the Astragaleae.^[31] This separation underscores the genus's dynamic systematics, with molecular data continuing to refine boundaries.^[32]

Etymology and history

The genus name Astragalus derives from the ancient Greek word astragalos, meaning "ankle bone" or "vertebra," a reference to the shape of the seeds or pods in some species, which resemble the knucklebones used as dice in antiquity.^[33]^[34] The genus was formally established by Carl Linnaeus in his 1753 work Species Plantarum, where he described 33 species.^[35] Early botanical exploration expanded knowledge of the genus, with Frederick Pursh documenting several North American species in his 1813 Flora Americae Septentrionalis, highlighting its diversity beyond Europe.^[36] In the 20th century, Rupert C. Barneby advanced the systematic study through his comprehensive monographs, most notably the two-volume Atlas of North American Astragalus published in 1964, which cataloged over 500 taxa and resolved numerous taxonomic ambiguities.^[37] Nomenclaturally, the genus has undergone refinements, including the lectotypification of Astragalus glycyphyllos L. as the type species in the early 20th century, and the broader reclassification of its family from Leguminosae (as used by Linnaeus and early systematists) to the conserved name Fabaceae under modern codes.^[35]^[38] Culturally, Astragalus species appear in medieval European herbals for their purported diuretic and tonic properties, while extracts like tragacanth gum from A. gummifer featured in early modern pharmacopeias as emulsifiers and binders in medicinal preparations.^[39]

Distribution and habitat

Global range

The genus Astragalus L. (Fabaceae), one of the largest in the plant kingdom with approximately 3,000 species, exhibits a cosmopolitan distribution but is predominantly native to the temperate and subtropical regions of the Northern Hemisphere, extending secondarily into parts of the Southern Hemisphere.^[1] Its range spans from the Arctic tundra to tropical African mountains, encompassing Eurasia, North America, northern Africa, and southward to Ecuador and southern South America, with the majority of species concentrated in arid and semi-arid zones.^[1]^[40] The primary center of diversity lies in Central and Southwest Asia, particularly the steppes and mountainous regions, where post-glacial migrations and vicariance events following the Pleistocene have significantly shaped species distributions.^[41] Iran hosts over 850 species, with more than 500 endemics, while Turkey records about 445 species, including 224 endemics; together, these countries account for a substantial portion of the Old World's approximately 2,750 taxa.^[42]^[43] In Europe, roughly 130–200 species occur, with notable endemism in the Mediterranean Basin due to historical isolation in refugia during glacial periods.^[44] North America supports over 400 species, primarily in the western United States and Rocky Mountains, where high endemism reflects adaptation to diverse arid habitats post-glaciation.^[45]^[26] While native presence in South America and Africa is limited to fewer than 100 species each, mostly in montane areas, human activities have facilitated expansions beyond natural ranges.^[1] For instance, A. glycyphyllos has been introduced to Australia, where it occurs as a non-native species.^[46] Additionally, A. membranaceus, native to East Asia, is now cultivated in North America for medicinal purposes, contributing to its localized spread.^[47] These patterns underscore the role of both natural biogeographic processes and anthropogenic influences in the genus's global range.^[48]

Habitat preferences

Astragalus species predominantly inhabit temperate grasslands, steppes, deserts, and montane regions, where they exhibit remarkable adaptations to xeric conditions, including drought tolerance through efficient water use and deep root systems. These biomes, characterized by low precipitation and high solar radiation, support the genus's hyper-diversity, with over 3,000 species thriving in semi-arid and arid environments across central Asia and western North America.^[49]^[40] Soil preferences for Astragalus emphasize well-drained, sandy or gravelly substrates, often poor in nutrients such as calcisols, cambisols, and regosols, which are prevalent in cold and arid zones. The genus's ability to form symbiotic relationships with Rhizobium bacteria in root nodules enables nitrogen fixation, allowing colonization of nutrient-deficient soils and enhancing ecosystem fertility in these harsh settings.^[49]^[50]^[51] Climatically, Astragalus displays broad tolerances, with alpine species demonstrating cold hardiness by fixing nitrogen at soil temperatures as low as 0°C and surviving in continental climates below -20°C, while arid-adapted forms resist drought through physiological mechanisms suited to high diurnal temperature fluctuations. The genus occupies an altitudinal range from sea level, including coastal and riverine areas, to over 5,000 meters in the Himalayas, where species endure extreme cold and low oxygen at high elevations.^[52]^[53]^[54] Microhabitat variations within Astragalus highlight growth form diversity, such as cushion-like habits in species like Astragalus siculus that stabilize rocky screes and alpine slopes by trapping soil and moderating microclimates, contrasted with erect forms in species like Astragalus adsurgens that dominate open prairies and grasslands through upright stems facilitating seed dispersal in windy conditions.^[55]^[56]

Ecology

Pollination and dispersal

Astragalus species are predominantly entomophilous, relying on insect pollinators for reproduction, with bees from the order Hymenoptera serving as the primary agents.^[57] Large-bodied bees in the families Apidae and Anthophoridae, such as Anthophora porterae, are key pollinators for several taxa, including A. phoenix and A. cibarius, where they effect sternotribic pollen transfer by tripping the floral keel mechanism.^[57]^[58] These bees collect nectar and pollen as rewards, exhibiting high floral constancy when multiple Astragalus species co-occur, which promotes outcrossing.^[59] Some North American species, like A. canadensis, attract specialist pollinators including Anthidium tenuiflorae, aligning with spring phenology to maximize visitation during peak bee activity.^[60] While most Astragalus flowers are chasmogamous and favor xenogamy, certain species exhibit self-pollination through cleistogamous flowers, as seen in A. cymbicarpos, or autogamy in A. argaeus, providing reproductive assurance in pollinator-scarce conditions.^[61]^[12] Seed dispersal in Astragalus occurs through multiple mechanisms adapted to arid and semi-arid environments. Autochory via explosive pod dehiscence propels seeds short distances from the parent plant in many species, triggered by drying tensions in the legume pods. Anemochory predominates in habitat-restricted taxa like A. holmgreniorum, where winged or sail-like pods remodel structurally in response to wind cues, facilitating local dispersal while rain-induced opening retains seeds near suitable microsites.^[62] Zoochory contributes via epizoochory, with hooked or spiny pod structures adhering to animal fur for external transport, enhancing spread across patchy landscapes.^[63] Astragalus seeds form persistent soil seed banks, enabling long-term survival and staggered germination in unpredictable environments. Seeds exhibit physical dormancy due to impermeable coats, persisting for decades—up to 130 years in dry storage for A. contortuplicatus—and contributing to transient or long-lived banks depending on species.^[64] Germination cues include heat shock from fire, which breaks dormancy in species like A. tragacantha and A. nevadensis, and moisture from flooding or seasonal rains, promoting emergence when conditions favor establishment.^[65] Habitat fragmentation exacerbates reproductive barriers for Astragalus by reducing pollinator access and diversity. Declines in bee populations, driven by isolation of remnants, lead to pollen limitation and lower seed set, as observed in fragmented populations of A. tragacantha and A. lentiginosus var. coachellae, where small patches experience reduced visitation and increased selfing.^[66]^[67] This impacts overall population persistence, particularly for outcrossing-dependent taxa.^[68]

Interactions with herbivores and pathogens

Astragalus species face substantial pressure from herbivory by a range of vertebrates and invertebrates, which can influence plant fitness and community dynamics. Large mammals such as deer, elk, sheep, and cattle frequently browse on palatable Astragalus foliage and pods, particularly in rangeland ecosystems where locoweed species predominate. For instance, species like Astragalus mollissimus produce the indolizidine alkaloid swainsonine, which, while toxic to livestock and causing locoism—a syndrome characterized by neurological dysfunction, weight loss, and reproductive failure—does not fully deter grazing by these herbivores. Insect herbivores also target Astragalus, with seed beetles (Acanthoscelides fraterculus) infesting seeds of selenium-accumulating species like A. bisulcatus, and bruchid wasps (Bruchophagus huonchili) damaging seed production in medicinal A. membranaceus. These interactions often result in significant tissue loss, with browsing reducing photosynthetic capacity and insect attacks directly curtailing reproductive output. Pathogenic organisms further exacerbate biotic stress on Astragalus populations. Fungal pathogens, particularly Fusarium oxysporum, induce root rot in cultivated and wild species such as A. membranaceus var. mongholicus, leading to wilting, stunted growth, and high mortality rates in dense stands under moist conditions. This soil-borne disease disrupts nutrient uptake and can spread rapidly during outbreaks, contributing to significant yield losses, often exceeding 30% in agricultural settings.^[69] Additionally, the root nodules formed by symbiotic rhizobia for nitrogen fixation are vulnerable to parasitism by atypical or non-fixing bacteria, including opportunistic pathogens that colonize nodules without providing benefits, thereby reducing symbiotic efficiency and plant vigor. While viral diseases are less documented in Astragalus, the overall pathogen load can compound herbivory effects by weakening plant defenses. Astragalus employs both constitutive and induced mechanisms to counter these antagonists. Chemical defenses, including alkaloids like swainsonine in locoweed species, act as feeding deterrents against small mammals such as rats, though they are less effective against larger browsers. Physical barriers, such as spines on pods and stems in certain arid-adapted species (e.g., A. drummondii), impede insect movement and limit access to reproductive structures, enhancing survival in high-herbivory environments. Following attack, plants activate induced responses, including the upregulation of secondary metabolites and signaling pathways triggered by herbivore elicitors or mechanical damage; for example, cotyledon loss in A. membranaceus seedlings prompts metabolic shifts that bolster regrowth and resistance to subsequent feeding. These interactions extend to broader food web dynamics through trophic cascades. Astragalus hosts specialist herbivores like the aphid Aphis astragali, which feeds on phloem and attracts parasitoid wasps such as Lysiphlebus fabarum, thereby supporting predator populations that regulate aphid outbreaks and indirectly benefit co-occurring plants. Outbreaks of herbivores or pathogens can profoundly impact Astragalus demography; pre-dispersal seed predation by insects constrains population growth in species like A. utahensis, reducing seed set by up to 90% in some populations and limiting range expansion. Similarly, root rot epidemics in dense stands diminish seedling recruitment and overall biomass, illustrating how antagonistic biotic pressures shape Astragalus ecology and underscore the need for integrated management in pastoral and conservation contexts.

Chemical composition

Primary compounds

Astragalus species contain a diverse array of primary compounds, including flavonoids, polysaccharides, saponins, alkaloids, and miscellaneous constituents like amino acids and trace minerals, which contribute to their structural integrity and bioactive potential. These compounds vary in composition and concentration across the genus, influenced by species, plant part, and environmental factors. Flavonoids such as astragalin (kaempferol-3-O-glucoside) and isorhamnetin are prominent in many Astragalus taxa, displaying antioxidant properties through mechanisms like free radical scavenging and metal ion chelation. For instance, astragalin has been identified in species including A. membranaceus and A. sinicus, while isorhamnetin occurs as glycosides in A. armatus and A. mongholicus. Concentrations of these flavonoids differ significantly by species and tissue; roots of A. membranaceus often exhibit elevated levels, with total flavonoid content reaching up to several milligrams per gram in optimized extracts.^[70]^[71] Polysaccharides, particularly astragalus polysaccharides (APS), function as key immunomodulators due to their complex carbohydrate structures, such as acidic heteropolysaccharides with molecular weights around 7-10 kDa. APS are commonly isolated from roots via hot water extraction at temperatures of 80-100°C, followed by ethanol precipitation and purification, yielding polysaccharides rich in glucose, galactose, and arabinose residues. This method achieves extraction rates of approximately 3-5% from dry material, with variations depending on the species like A. membranaceus.^[72]^[73] Saponins in Astragalus primarily consist of triterpenoid glycosides, including astragalosides I-IV, which are cycloartane-type structures derived from roots of species such as A. membranaceus. These compounds are linked to cardioprotective effects through their ability to modulate cellular signaling and reduce oxidative stress in cardiac tissues. Over 30 saponins have been characterized in recent analyses, with astragaloside IV being the most studied due to its prevalence in medicinal varieties.^[74]^[75] Alkaloids, particularly in toxic species, include swainsonine and other indolizidine alkaloids that induce neurological damage by inhibiting lysosomal enzymes like α-mannosidase, leading to glycoprotein storage disorders. Swainsonine has been detected in numerous taxa, such as certain North and South American Astragalus species (e.g., A. mollissimus and 16 South American variants), with concentrations varying from trace to several micrograms per gram in locoweed forms. These alkaloids are biosynthesized in association with endophytic fungi in some cases.^[76] Other compounds encompass amino acids and trace minerals such as calcium, iron, and magnesium acquired through symbiotic nitrogen fixation with rhizobia. In species like A. mongholicus, nitrogen-fixing bacteria enhance the uptake of these minerals, contributing to overall mineral content in roots and shoots.

Biosynthesis pathways

The biosynthesis of key compounds in Astragalus species occurs through specialized metabolic pathways that branch from primary metabolism, enabling the production of flavonoids, polysaccharides, saponins, and alkaloids essential for plant adaptation and defense. These pathways are tightly regulated at transcriptional and enzymatic levels, with contributions from cytochrome P450 monooxygenases facilitating oxidative modifications across multiple routes.^[77] Flavonoids in Astragalus are synthesized via the phenylpropanoid pathway, starting from L-phenylalanine, which is converted to p-coumaroyl-CoA by phenylalanine ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H, a cytochrome P450 enzyme). Chalcone synthase (CHS) then catalyzes the condensation of p-coumaroyl-CoA with malonyl-CoA to form naringenin chalcone, the first committed intermediate, which is isomerized by chalcone isomerase (CHI) to naringenin and further modified into various flavones and isoflavones, often through glycosylation by UDP-glycosyltransferases to yield bioactive glycosylated forms such as calycosin-7-O-β-D-glucoside.^[78]^[79]^[80] This pathway is upregulated under environmental stress, including UV irradiation and mechanical wounding, which induce PAL and CHS expression to enhance flavonoid accumulation for protection against oxidative damage.^[77] Polysaccharide synthesis in Astragalus membranaceus involves the activation of glucose to UDP-glucose by UDP-glucose pyrophosphorylase (UGPase), serving as the primary glycosyl donor for chain elongation. UDP-glucose is transported into the Golgi apparatus, where glycosyltransferases facilitate polymerization of monosaccharides like D-glucose, D-galactose, and L-arabinose into complex heteropolysaccharides, including acidic types with rhamnogalacturonan backbones.^[81]^[82] Elicitors such as methyl jasmonate or chitosan applied to roots upregulate genes encoding UGPase and related transferases, increasing polysaccharide yield by activating defense signaling cascades that enhance flux through this pathway.^[83]^[84] Saponins, particularly astragalosides in A. membranaceus, are triterpenoid glycosides biosynthesized via the mevalonate (MVA) pathway in the cytosol, where acetyl-CoA is converted stepwise to isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which condense to form farnesyl pyrophosphate and ultimately squalene via squalene synthase. Squalene is oxidized to 2,3-oxidosqualene, cyclized by β-amyrin synthase (β-AS, an oxidosqualene cyclase) to β-amyrin, and further modified by cytochrome P450 enzymes (e.g., CYP93E subfamily) through hydroxylation and oxidation before terminal glycosylation with UDP-sugars to produce bioactive saponins.^[77]^[85] The identification of Amβ-AS genes has confirmed their role in directing flux toward cycloartane-type triterpenes characteristic of Astragalus.^[86] In locoweed species like Astragalus and Oxytropis, the indolizidine alkaloid swainsonine is produced via a pipecolic acid pathway facilitated by symbiotic endophytic fungi such as Undifilum oxytropis. Lysine is decarboxylated to cadaverine, transaminated to piperideine, and reduced to pipecolic acid, which serves as a precursor for swainsonine ring formation through enzymatic steps including those encoded by fungal genes like swnT for piperidine synthase activity, with the endophyte providing the full biosynthetic machinery absent in the plant host.^[87]^[88]^[89] Environmental stresses such as drought and herbivory significantly influence these pathways in Astragalus by triggering transcriptional reprogramming and enzymatic activation. Drought induces phenylpropanoid and isoflavonoid flux through upregulation of PAL and CHS, mediated by stress-responsive transcription factors, while herbivory elicits jasmonate signaling that boosts saponin and polysaccharide production via cytochrome P450-mediated oxidations, enhancing plant resilience without compromising growth under moderate stress levels.^[90]^[91]^[92]

Uses

Medicinal applications

In traditional Chinese medicine, Astragalus membranaceus, known as Huang Qi, serves as a key qi tonic to bolster immune function, alleviate fatigue, and promote wound healing.^[93] It is commonly incorporated into formulations such as Bu Zhong Yi Qi Tang, which addresses qi deficiency and related symptoms like weakness and poor digestion.^[94] Modern pharmacological research highlights the immunomodulatory effects of astragalus polysaccharides (APS) from A. membranaceus, particularly in mitigating chemotherapy-induced side effects such as leukopenia, thrombocytopenia, and fatigue.^[95] Research has explored the immunomodulatory effects of APS as a potential adjunct therapy for various viral infections.^[96]^[97] For cardiovascular applications, astragalosides derived from A. membranaceus demonstrate benefits in heart failure management, with meta-analyses indicating improvements in left ventricular ejection fraction and reductions in remodeling when used alongside conventional treatments.^[98]^[99] Astragalus exhibits anti-aging and adaptogenic properties, primarily through antioxidant activity and telomere protection mechanisms observed in animal models, where extracts like TA-65 from the plant elongate short telomeres and mitigate oxidative stress.^[93]^[100] Preparations typically involve root extracts standardized to 0.5% astragalosides for consistent potency, with doses of up to 60 grams daily by mouth for up to 4 months appearing safe for most adults without significant adverse effects.^[101]

Agricultural and ornamental uses

Astragalus species, particularly non-toxic varieties such as Astragalus cicer (cicer milkvetch), are employed as forage crops in pastures across various regions, providing nutritious feed for livestock like cattle and sheep. Unlike alfalfa, cicer milkvetch does not cause bloat in grazing animals, making it a safer option for hay and grazing systems. Its deep root system facilitates soil improvement through biological nitrogen fixation, where symbiotic bacteria convert atmospheric nitrogen into forms usable by plants, thereby enhancing soil fertility and reducing the need for synthetic fertilizers. This legume is well-adapted to a range of soil types, including those with high salinity or alkalinity, and supports sustainable pasture management in semi-arid areas.^[102]^[103]^[104] As a cover crop, A. cicer is integrated into rotations with grains or other crops to restore soil health and prevent nutrient depletion. It excels in improving soil structure and organic matter content while suppressing weeds through competitive growth. Establishment guidelines recommend seeding rates of 5 to 8 pounds per acre for pure stands, or 2 to 4 pounds per acre when mixed with grasses, sown at a depth of ¼ to ½ inch into a firm seedbed during early spring or fall. Successful establishment requires adequate moisture during germination, after which the plant's perennial nature ensures long-term benefits, with stands persisting for over a decade in suitable conditions.^[105]^[106] In ornamental horticulture, drought-tolerant Astragalus species like A. angustifolius (narrow-leaved milkvetch) are prized for xeriscaping and rock gardens, where water conservation is paramount. This compact, evergreen subshrub, native to Mediterranean regions, features silvery-gray, narrow foliage and clusters of small white or pale pink flowers in spring, thriving in well-drained, rocky soils with minimal irrigation once established. Cultivars such as those propagated for alpine displays offer resilience to poor soils and extreme temperatures, contributing to low-maintenance landscapes that mimic natural arid habitats.^[107]^[108] The fibrous root networks of Astragalus species make them effective for erosion control in arid and semi-arid environments, including slopes and disturbed sites in the U.S. Great Plains. Varieties like 'Lutana' cicer milkvetch are specifically recommended for stabilizing soil on critical areas, such as road banks or reclaimed lands, by binding loose particles and promoting ground cover. In regional projects, such as those in Montana and the northern Plains, these plants have been sown to mitigate wind and water erosion, with success rates improved by incorporating them into seed mixes for native prairie restoration.^[106]^[109] Despite these benefits, the introduction of non-native Astragalus species carries challenges, including the potential for them to become invasive weeds in rangelands. For example, A. cicer has emerged as a concern in parts of the Midwest, where it spreads beyond intended areas, outcompeting native grasses and altering ecosystems. Management strategies, such as monitoring seeding sites and avoiding overplanting, are essential to prevent unintended invasions.^[110]

Toxicity and risks

Poisonous species

Several species within the genus Astragalus are recognized for their toxicity, primarily due to the accumulation of specific compounds that pose risks to grazing animals. The locoweed group includes more than 20 North American species that produce swainsonine, an indolizidine alkaloid synthesized by fungal endophytes of the genus Undifilum.^[111]^[112] Representative examples are A. lentiginosus (spotted locoweed) and A. mollissimus (woolly locoweed), which are perennial herbs found in arid and semi-arid regions.^[113] Another category consists of selenium-accumulating species, such as A. bisulcatus (two-grooved milkvetch), which can hyperaccumulate selenium to levels exceeding 1% of dry weight in selenium-rich soils, leading to selenosis in livestock known as blind staggers.^[114] These plants thrive in alkaline, selenium-laden soils of the western United States.^[115] In Europe, certain alkaloid-rich taxa, such as A. hamosus, contain toxic nitropropionic acid derivatives like 3-nitropropionic acid (3-NPA), which are aliphatic nitro compounds responsible for respiratory and neurological effects in herbivores.^[116] These compounds occur in various Old World sections of the genus.^[117] Distinguishing toxic from non-toxic Astragalus species often relies on morphological and ecological traits. Toxic locoweeds frequently exhibit glandular or strigose hairs on stems and leaves, inflated or linear pods with septa, and preference for dry, open rangelands or disturbed soils in foothills and plains.^[118] In contrast, many safe milkvetches lack these glandular pubescences and occupy moister habitats.^[118] The incidence of poisonous Astragalus is most pronounced in the western U.S. rangelands, where locoweeds and selenium accumulators contribute to substantial livestock losses, estimated at $100 million annually due to reduced productivity and mortality.^[119]

Effects on livestock and humans

Astragalus species containing swainsonine, an indolizidine alkaloid, induce locoism in livestock such as cattle, sheep, and horses through chronic ingestion, manifesting as neurological symptoms including ataxia, depression, aggression, and intention tremors, alongside emaciation and weight loss due to lysosomal storage disease from inhibited glycoprotein metabolism.^[120] In pregnant animals, swainsonine exposure leads to abortion, fetal abnormalities, and reduced libido or spermatogenesis in males, with effects persisting even after cessation of intake.^[121] Certain Astragalus species hyperaccumulate selenium, causing chronic selenosis known as alkali disease, characterized by hair loss from the mane and tail, hoof deformities such as cracking and sloughing, and impaired reproduction including embryonic death.^[122] Acute selenium overload from these plants can result in blind staggers, with symptoms like blindness, circling, and head pressing in cattle and sheep.^[123] Human exposure to toxic Astragalus species is rare and typically involves accidental ingestion of plant material, leading to mild gastrointestinal upset such as nausea, vomiting, and diarrhea from direct mucosal irritation.^[124] In the context of herbal supplements derived from non-toxic Astragalus varieties, potential risks include drug interactions, such as reduced clearance of lithium or exacerbation of autoimmune conditions, though these are not linked to the poisonous species.^[125] Selenium accumulation in edible plants like Astragalus may contribute to human selenosis if consumed in contaminated food, presenting with symptoms like garlicky breath, hair and nail brittleness, but documented cases from direct plant ingestion are uncommon.^[126] Chronic exposure in livestock to swainsonine at dietary levels exceeding approximately 0.3 mg per kg body weight per day—equivalent to consuming locoweed comprising about 10-20% of the diet depending on plant alkaloid concentration—results in progressive reproductive toxicity, including infertility and teratogenic effects in offspring.^[127] Selenium chronic toxicity thresholds in livestock diets are around 5-10 mg per kg of feed, leading to cumulative organ damage beyond acute symptoms.^[122] Diagnosis of swainsonine-induced locoism relies on clinical observation of neurological deficits and histopathological confirmation of vacuolar degeneration in lysosomes of multiple organs, with elevated serum swainsonine levels indicating exposure; elevated liver enzymes like aspartate aminotransferase may occur secondary to tissue damage.^[128] For selenium toxicity, diagnosis involves measuring blood selenium concentrations exceeding 1 mg/L and observing characteristic gross lesions like lame gaits.^[122] Mitigation strategies emphasize grazing avoidance through rotational management and fencing high-risk areas, as rumen microbial adaptation to detoxify swainsonine is limited and inconsistent across animals; supplemental feeding with high-quality forage can reduce plant intake.^[129] Notable case studies from the early 20th century in the western United States, such as widespread locoism outbreaks in Wyoming and Utah rangelands during the 1910s-1920s affecting thousands of cattle and sheep, highlighted the economic impact of unchecked grazing on Astragalus-dominated pastures and spurred federal research into plant identification and management practices.^[120] Similarly, selenium poisoning epidemics in South Dakota's alkali soils in the 1930s, linked to Astragalus bisulcatus consumption, informed soil mapping and livestock relocation protocols that reduced incidence by over 50% in subsequent decades.^[130]

Conservation status

Threatened species

Several dozen species within the genus Astragalus are assessed as threatened by conservation authorities, including the International Union for Conservation of Nature (IUCN) and national lists, with over 50 taxa classified as rare, threatened, or endangered in California alone, representing about 35% of the state's native Astragalus diversity.^[131] These vulnerabilities often stem from the genus's high rate of narrow endemism, where species are restricted to small, specialized habitats prone to disruption. For instance, Astragalus claranus (Clara Hunt's milk-vetch) is listed as endangered in California, facing severe risks from urbanization and associated habitat fragmentation in coastal regions.^[132] Regional threats exacerbate these risks in various parts of the world. In the Mediterranean Basin, Astragalus nitidiflorus, a short-lived perennial endemic to southeastern Spain, was classified as critically endangered but is now listed as extinct (EX) by the IUCN due to habitat loss from agricultural intensification and expansion, which has reduced suitable shrubland areas.^[133]^[134]^[135] In the United States, mining activities pose a significant danger to Astragalus jaegerianus (Lane Mountain milk-vetch), an endangered species in the Mojave Desert of California, where ore extraction and associated disturbances have fragmented its granitic soil habitats and directly destroyed populations.^[136]^[137] Narrow endemics highlight the genus's susceptibility to localized pressures. Astragalus schmolliae (Chapin Mesa milk-vetch), known only from mesa tops in a restricted area of southwestern Colorado, holds a global rank of G1 (critically imperiled) by NatureServe and faces threats from climate change, including projected increases in temperature and altered precipitation patterns that could shift its pinyon-juniper woodland habitat beyond viability, though a proposed listing under the U.S. Endangered Species Act was withdrawn in 2022.^[138]^[139]^[140] Population monitoring for such species often reveals sharp declines; for example, some Astragalus endemics in fragmented landscapes have experienced reductions of 30-50% over the past few decades due to these cumulative threats.^[131] Habitat fragmentation also drives genetic diversity loss in surviving populations, increasing inbreeding risks. In A. nitidiflorus, small, isolated patches exhibited low genetic variation prior to its extinction, heightening vulnerability to environmental stochasticity and further decline.^[141] Similarly, for A. jaegerianus, ongoing habitat isolation from mining has led to reduced gene flow, with populations showing signs of diminished diversity that could impair long-term resilience.^[142]

Conservation efforts

Conservation efforts for Astragalus species emphasize habitat protection, ex situ preservation, legal safeguards, scientific research, and stakeholder engagement to maintain biodiversity across this diverse genus. Globally, initiatives include seed banking and habitat restoration in Asia, where rare endemics like certain A. membranaceus variants are protected under China's national red lists through botanical gardens and protected areas. In the United States, several endemic species benefit from inclusion in protected areas, such as Grand Canyon National Park, where the endangered sentry milk-vetch (Astragalus cremnophylax var. cremnophylax) is safeguarded through rim-edge monitoring and restricted access to prevent trampling.^[143] Habitat restoration projects, including the construction of exclosure fences around sensitive populations, have been implemented for species like Packard's milkvetch (Astragalus cusickii var. packardiae) in Idaho to exclude livestock and promote recovery.^[144] Ex situ conservation plays a vital role in preserving genetic diversity, with seed collections of multiple Astragalus species stored at the Millennium Seed Bank Partnership, including protocols for species like purple milk-vetch (Astragalus danicus) involving harvests from July to August to ensure long-term viability.^[145] Propagation efforts, such as those for Pyne's ground-plum (Astragalus bibullatus), focus on seed germination studies and banking to support reintroduction, with collections yielding thousands of seeds from wild populations.^[146] These initiatives extend to over a dozen U.S. taxa, aiding in the conservation of rare variants through controlled cultivation and seed viability testing.^[147] Legal protections under the U.S. Endangered Species Act (ESA) cover more than ten Astragalus taxa, including endangered listings for species like Lane Mountain milk-vetch (Astragalus jaegerianus) and Mancos milkvetch (Astragalus humillimus), which prohibit take and require habitat conservation plans.^[137]^[148] For instance, the threatened Peirson's milkvetch (Astragalus magdalenae var. peirsonii) benefits from designated critical habitat on federal lands, encompassing over 49,000 acres closed to off-road vehicles.^[149] Research and monitoring efforts include genetic studies to inform reintroduction, such as those for Holmgren milk-vetch (Astragalus holmgreniorum), where recovery plans developed since 2000 analyze population genetics and life-history traits to enhance survivorship in desert habitats.^[150]^[151] These plans, finalized in 2006, outline delisting criteria based on sustained populations across protected sites.^[152] Ongoing monitoring, like the 2025 revised recovery plan for sentry milk-vetch, tracks reproductive success and genetic divergence to guide adaptive management.^[153] Community involvement focuses on grazing restrictions and education in rangelands, with conservation agreements implementing seasonal closures and exclosures to reduce trampling for species like Deseret milkvetch (Astragalus desereticus), which led to its delisting in 2018 after population stabilization.^[154] Multi-agency strategies, such as those for Cisco milkvetch (Astragalus cibarius) in Utah, engage landowners in monitoring and habitat enhancement to prevent overharvesting of medicinally valuable species.^[155] Educational programs raise awareness among ranchers, emphasizing best management practices to balance land use with biodiversity goals.^[156]

References

[1]
Ethnobotanical knowledge of Astragalus spp.: The world's largest ...
Astragalus L. (Fabaceae) is the largest genus of vascular plants in the world, that comprises an estimated number of 2900 annual and perennial species.
[2]
[PDF] Exploring Evolutionary Relationships of New World Astragalus ...
The legume genus Astragalus, within the Fabaceae family, is the most diverse genus of plants, comprising nearly 3,000 species (Wojciechowski, 2005). Beyond its ...<|control11|><|separator|>
[3]
Scarlet Milkvetch - USDA Forest Service
Astragalus is a very large genus of the legume family (Fabaceae). Another name is “milkvetch,” which is said to be the designation for less poisonous (or ...
[4]
A review of the botany, phytochemistry, traditional uses ...
Aug 23, 2023 · This review systematically summarizes the botanical characteristics, phytochemistry, traditional uses, pharmacology, and toxicology of Astragalus
[5]
Review of the botanical characteristics, phytochemistry ... - PubMed
Astragalus membranaceus is one of the most widely used traditional Chinese herbal medicines. It is used as immune stimulant, tonic, antioxidant, ...
[6]
The demographic and ecological factors shaping diversification ...
May 6, 2021 · Astragalus is the largest plant genus in the world and is disproportionately comprised of rare species restricted to narrow geographic and ...
[7]
[PDF] 139. ASTRAGALUS Linnaeus, Sp. Pl. 2: 755. 1753.
Jun 20, 2007 · 1753. Annual or perennial herbs, subshrubs, or shrubs, often sometimes spiny, glabrous or hairy; hairs basifixed or symmetrically or ...
[8]
https://www.cnhp.colostate.edu/download/documents/Spp_assessments/astragaluswetherillii.pdf
[9]
(species) astragalus arrectus - Montana Field Guide
The fruit pods are leathery at maturity and split open to release the seeds passively (Barneby 1964). The seeds do not possess any wings, barbs, or hooks to ...
[10]
[PDF] studies of the natural history of astragalus magdalenae var. peirsonii
Jun 17, 2005 · The root system of Peirson's milkvetch is composed of a deep taproot (sometimes more than four meters deep) and shallow lateral roots that ...
[11]
[PDF] Reproductive ecology of Astragalus filipes, a Great Basin restoration ...
filipes requires a pollinator and benefits from outcrossing (Chapter 2), I do not know the identity of its wild pollinators. Pollination studies conducted ...
[12]
Reproductive Biology of <i>Astragalus argaeus</i> (Fabaceae), a ...
According to the results from pollination experiments, A. argaeus was autogamous but benefit from the cross pollination (xenogamous) and the presence of ...
[13]
THE POLLINATION ECOLOGY OF ASTRAGALUS CIBARIUS AND ...
Several A. cibarius flowers showed a trace of ultraviolet reflectance, coin- ciding with the nectar guides, but the results were not conclusive.
[14]
[PDF] Seed propagation in four perennial species of Astragalus ... - Zobodat
Additionally, the presence of the septum and patterns of its lignification and fusion with the ovary wall define the mode of pod dehiscence (e.g. Holden 1952). ...
[15]
Germination pretreatments to break hard-seed dormancy in ...
Nov 3, 2016 · Conclusions. Physical scarification is a simple, safe, and reliable way to improve germination rates in Astragalus species with hard seed ...Missing: production pod
[16]
Seed dormancy and germination characteristics of Astragalus ...
Typically, the species are low-growing shrubs or herbaceous perennials, and relatively few of them are annuals. For example, about 120 species of Astragalus ...
[17]
Astragalus canadensis - FNA - Flora of North America
Mar 12, 2025 · Plants usually robust, rarely quite slender, (10–)15–120(–160) cm, strigose; from oblique or horizontal rhizomes.
[18]
(PDF) High Clonal and Low Sexual Reproduction in Fragmented ...
Aug 6, 2025 · We outline suggestions for future demographic and genetic monitoring, and we emphasize the need for breeding system and pollination biology ...
[19]
https://onlinelibrary.wiley.com/doi/10.1111/aab.12851
[20]
New insights into the phylogenetic relationships of tribe Astragaleae ...
Dec 10, 2024 · Astragaleae is one of the largest tribes in the legume family and includes Astragalus, the most species-rich genus in angiosperm. The ...
[21]
A new species of Astragalus (Fabaceae) from the Irano-Turanian ...
Jan 8, 2025 · It is characterized by remarkable morphological diversity and high levels of endemism, especially in Southwestern Asia (Podlech and Zarre 2013; ...
[22]
Astragalus - Trees and Shrubs Online
Currently Astragalus is most often placed either in Tribe Galegeae or Astragaleae. The most similar familiar genus is Oxytropis, and some molecular work ...Missing: Fabeae | Show results with:Fabeae
[23]
Evidence on the Monophyly of Astragalus (Fabaceae) and its Major ...
Phylogenetic relationships among 115 species representing the legume genus Astragalus and. 12 related genera were inferred from an analysis of nucleotide ...
[24]
https://bsapubs.onlinelibrary.wiley.com/doi/10.1002/ajb2.70084
[25]
North American Species of Astragalus Linnaeus (Leguminosae)
This summary revision of the species of Astragalus in North America, north of Mexico, was initially prepared for inclusion in the Flora North America Project.
[26]
[PDF] Genetic characterization of three varieties of Astragalus lentiginosus ...
Barneby's treatments (1945, 1964, 1989) reduced the group back to a single species,. Astragalus lentiginosus, with ca. 40 varie- ties. This classification came ...
[27]
Astragalus leptaleus - FNA
Mar 12, 2025 · genusAstragalus. sectionAstragalus sect. Astragalus. speciesAstragalus leptaleus. Astragalus leptaleus. A. Gray. Proc. Amer. Acad. Arts 6: 220 ...Missing: Leptalei pod structure
[28]
Biosystematic Study on Some Egyptian Species of Astragalus L ...
Feb 4, 2021 · Astragalus L. is one of the largest angiosperm complex genera that belongs to the family Fabaceae, subfamily Papilionoideae or Faboideae ...2.1. Taxonomy Study · 3. Results · 3.2. Molecular Data Analysis<|separator|>
[29]
[PDF] A NEW INFRAGENERIC GROUPING OF ASTRAGALUS (FABACEAE)
Astragalus species with chromosome base numbers of x=11, 12, 13, 14 and15 form a clade within the Old. World Astragalus the so called Neo-Astragalus.
[30]
FNA: Oxytropis - Northwest Wildflowers
Separation of Oxytropis from Astragalus has long been argued, and the history of the discussion was outlined by R. C. Barneby (1952b) and S. L. Welsh (1989).Missing: synonymy | Show results with:synonymy
[31]
"Phylogenetic relationships between Oxytropis DC. and Astragalus L ...
Oxytropis and Astragalus represent one of the largest angiosperm genera complexes. Although phylogenetic studies of this complex exist, the evolutionary ...Missing: synonymy | Show results with:synonymy
[32]
Botany A to Z: Astragalus - Colorado Natural Heritage Program
Dec 6, 2011 · By far the most frequent genus name on the tracking list is Astragalus, the milkvetches, which are members of the pea family.
[33]
Astragalus - Etymology, Origin & Meaning
Originating from Greek astragalos meaning "ankle bone" or "knuckle-bones," astragalus refers to a plant genus, an ankle bone, and an architectural molding.
[34]
[PDF] Current Status of the Systematics of Astragalus L. (Fabaceae) with ...
The chromosome numbers are also quite interesting and significant in Astragalus for its phylogenetic studies. There is a strong correlation between its.
[35]
Medical Properites and Usage of Astragalus Sp. - Traditional Medicine
Oct 19, 2024 · The medical use of Astragalus in treatment was known in the time of the famous Greek doctor Dioscorides, who lived in the MS.I. century. It ...Missing: Roman | Show results with:Roman
[36]
The Demise of the Name Astragalus tenellus Pursh (Fabaceae) - jstor
its author, Frederick Pursh. On page 473 of his Flora Americae ... Atlas of North American Astragalus. Mem. New York Bot. Gard. 13: 1-1188 ...
[37]
Monographs Details – The Barneby Catalogue
Authors: Rupert C. Barneby ; Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188. ; Family: Fabaceae.
[38]
The genus Astragalus (Leguminosae: Papilionoideae: Galegeae) in ...
Mar 7, 2023 · Astragalus is the most diverse genus within flowering plants with almost 2500 species, it is widely distributed around the world, very abundant ...
[39]
Astragalus gummifer - Ask Ayurveda
Oct 21, 2025 · In early modern Europe (17th–18th c.), gum tragacanth appeared in Pharmacopeias as an excipient for tinctures and elixirs—valued for its ability ...
[40]
Astragalus L. | Plants of the World Online | Kew Science
Accepted Species. Includes 3095 Accepted Species. KB. Astragalus aaronii (Eig) Zohary · Astragalus aaronsohnianus Eig · Astragalus abadehensis Maassoumi & ...
[41]
The demographic and ecological factors shaping diversification ...
May 6, 2021 · Astragalus is a hyper-diverse genus that is prominent in montane and arid environments such as those that dominate the western United States.
[42]
[PDF] Biogeography and niche evolution in Astragalus - bioRxiv
Jun 29, 2023 · Astragalus species, relatively uniform in terms of morphology (primarily herbaceous perennials) and niche biology. (primarily arid and semi-arid ...
[43]
distribution of Astragalus sp. In the old World (eurasia) and new ...
Approximately 445 species of this genus grow in Turkey and among them 224 species are endemic. ...
[44]
(PDF) Maassoumi, A. A., 2020 : A Checklist of Astragalus in the world
Aug 1, 2022 · with different number of endemism in Asia, Europe, Africa and America. In. Europe with 134 spp. (61 endemics), SW Asia with 1484 spp. (1024.
[45]
Wild Licorice - Astragalus glycyphyllos - Atlas of Living Australia
Browse the list of datasets and find organisations you can join if you are interested in participating in a survey for species like Astragalus glycyphyllos L.
[46]
[PDF] cultivation practices for astragalus membranaceus in the
May 9, 2009 · The pollen, leaf vein, enzyme and root morphology are also different between the haired and unhaired A. membranaceus. Page 29. 14. (Xie et al., ...
[47]
Evolution, range formation and a revised taxonomy of the disjunctly ...
Members of Astragalus sect. Caprini (AEMAC) colonized Europe from the East and diversified after the Mid-Pleistocene-Transition (0.5–0.7 Ma).
[48]
[PDF] Biogeography and niche evolution in Astragalus
Jan 22, 2024 · The ecological dominance, species richness, and narrow endemism of Astragalus in many semi‐arid areas of the northern hemisphere and a smaller ...
[49]
Great diverse rhizobial community nodulating Astragalus ...
Many Astragalus species form nitrogen-fixing symbioses with rhizobia (Wei et al., 2003; Tian et al., 2021) that can fix atmospheric nitrogen and convert it ...
[50]
[PDF] Purple milkvetch (Astragalus agrestis) - Forest Service
The soils associated with purple milkvetch habitats are often described as seasonally moist and alkaline. Soil texture descriptions range from gravelly to sandy ...
[51]
Astragalus alpinus: INTRODUCTORY - Forest Service
Astragalus a. var. alpinus is found across North America, from Alaska to Newfoundland south to Nevada, New Mexico, and South Dakota.
[52]
Astragalus alpinus|alpine milk vetch/RHS Gardening
Drought resistance. Yes. Hardiness. Hardiness ratings. All ratings refer to the ... H7: hardy in the severest European continental climates (< -20). H7 ...
[53]
A Checklist of Astragalus in the world: New Grouping, New Changes ...
Sep 7, 2023 · PDF | This is a new version of Check list of Astragalus in the world. Several specific names were added into the new version.
[54]
Nitrogen‐fixing cushion Astragalus siculus modulates soil fertility ...
Jun 9, 2023 · Astragalus cushions have strong biogenic effects on above- and below-ground conditions by dramatically increasing soil organic carbon and total nitrogen stocks.Missing: screes | Show results with:screes
[55]
Astragalus adsurgens (Prairie Milkvetch) - Minnesota Wildflowers
Life cycle: perennial ; Origin: native ; Habitat: sun; dry prairie ; Bloom season: June - July ; Plant height: 6 to 16 inches.Missing: cushion rocky forms
[56]
[PDF] pollination biology of astragalus phoenix (fabaceae)
Astragalus is most diverse in montane regions, such as the Andes Moun- tains, western North America, and the Sino- Himalayan region (Allen and Allen 1981, ...
[57]
the pollination ecology of astragalus cibarius and astragalus ... - jstor
Numbers indicate banner (1), nectar guides (2), keel (3), and wing (4). 2. Flowering phenology of Astragalus and associated early flowering species at the ...
[58]
(PDF) On the pollination ecology of Astragalus alopecurus pallas ...
Aug 6, 2025 · Pollinators collected nectar, transferred the pollen sternotribically and demonstrated high flower constancy. Natural seed set showed at most ...
[59]
Canada Milk Vetch (Astragalus canadensis) - Wild Cherry Farm
It is also a host plant to the specialist bees Anthidium tenuiflorae, Megachile melanophaea, and Osmina integra (Johnson and Colla, 2023) and is a nectar ...
[60]
the heterochronic origin of the cleistogamous flower in astragalus ...
Jul 1, 1993 · Members of the species Astragalus cymbicarpos form chasmogamous and cleistogamous flowers, as well as a large variety of intermediate floral ...
[61]
dispersal ecology of a habitat‐restricted desert milkvetch
May 27, 2020 · We tested the hypothesis that informed dispersal in response to an environmental cue enables dispersal by wind on a local scale for Astragalus ...
[62]
(PDF) Dispersal of Holmgren's Milkvetch, Astragalus holmgreniorum ...
Nov 13, 2018 · Dispersal of Holmgren's Milkvetch, Astragalus holmgreniorum, Seed Pods by Wind. November 2018. Authors: Sydney Houghton McGovern at Utah ...
[63]
Seed of the threatened annual legume, Astragalus contortuplicatus ...
Sep 1, 2015 · Generally, germination of seed from seed banks should be preferred, as the material is stored under optimal conditions to maintain seed ...
[64]
The Effect of Heat Shock on Seed Dormancy Release and ...
Feb 8, 2024 · Many Astragalus species exhibit seeds with physical dormancy (PY), but little is known about the ecological context of this dormancy.
[65]
Pollination insights for the conservation of a rare threatened plant ...
Feb 27, 2019 · The increase in habitat fragmentation impacts plant-pollinator interactions and threatens the sustainability of plant species. Astragalus ...
[66]
[PDF] Astragalus lentiginosus var. coachellae (Coachella Valley milk-vetch ...
Oct 6, 1998 · Seed dispersal and pollinator movement can be inhibited by habitat fragmentation or degradation. Astragalus lentiginosus var. coachellae ...
[67]
Designation of Critical Habitat for Astragalus lentiginosus var ...
Jun 9, 2005 · We were influenced by their findings that showed that alteration and fragmentation of habitat used by pollinator species can lead to reduced ...
[68]
Flavonoids from the Genus Astragalus: Phytochemistry and ... - NIH
This paper is focused on the large group of flavonoid compounds. Details on structure as well as information about the pharmacological properties of flavonoids
[69]
https://pmc.ncbi.nlm.nih.gov/articles/PMC12388289/
[70]
A Review of the Pharmacological Action of Astragalus Polysaccharide
Mar 24, 2020 · Compared with the method of APS extraction using heated water, microwave-assisted extraction reduced the amount of extractant, shortened the ...Missing: hot | Show results with:hot
[71]
https://doi.org/10.1371/journal.pone.0165575
[72]
A Comparative Study on Inhibition of Total Astragalus Saponins and ...
Both total astragalus saponins (AST) and it's main component astragaloside IV (ASIV) have been used in China as cardiovascular protective medicines.
[73]
https://doi.org/10.1016/j.ijbiomac.2016.10.018
[74]
Screening for swainsonine among South American Astragalus species
Swainsonine is a toxic alkaloid found in several plant genera worldwide. The objective of this study was to screen several South American Astragalus species ...
[75]
Bioactive components and clinical potential of Astragalus species
Recent studies show that Astragalus species is rich in bioactive compounds, such as polysaccharides, flavonoids, saponins, alkaloids, and simple phenolics.Missing: spines | Show results with:spines
[76]
Does GABA increase the efficiency of symbiotic N2 fixation in ...
By the aid of 15N nuclear magnetic resonance (15N NMR), GABA was determined as the second most abundant amino acid of detached pea nodules.
[77]
Biosynthesis and Pharmacological Activities of Flavonoids ... - NIH
In this review, we comprehensively discussed the biosynthesis pathway of flavonoids and triterpenoid saponins, and the structural features of polysaccharides in ...Missing: isorhamnetin alkaloids
[78]
Transcriptional regulation mechanism of flavonoids biosynthesis ...
Naringenin chalcone is produced by chalcone synthase with p-coumaroyl CoA and malonyl CoA as substrate (Santín and Moncalián, 2018). Naringenin chalcone ...
[79]
Overexpression of chalcone isomerase A gene in Astragalus ...
Dec 17, 2021 · Chalcone isomerase is an important enzyme of the flavonoid biosynthesis pathway by converting the isomerization of chalcone to flavanone.
[80]
Phenylalanine ammonia lyase functions as a switch directly ...
Jun 25, 2008 · Phenylalanine ammonia lyase functions as a switch directly controlling the accumulation of calycosin and calycosin-7-O-β-D-glucoside in ...<|separator|>
[81]
Effect of different origins on genes encoding key enzymes involved ...
Apr 22, 2025 · These monosaccharides typically are converted through the UDP-Glc process, resulting in the formation of various sugars including UDP-Gal, UDP-D ...
[82]
Evidence for a UDP-Glucose Transporter in Golgi Apparatus ...
Using these vesicles and UDP-Glc, we reconstituted polysaccharide biosynthesis in vitro and found evidence for a luminal location of the active site of glucan ...Missing: Astragalus pathway
[83]
Elicitation: A biotechnological tool for enhanced production of ... - NIH
Elicitation with various biotic and abiotic elicitors has been widely applied to enhance the secondary metabolite production in hairy root cultures as well as ...
[84]
Heterologous Expression of Three Transcription Factors Differently ...
RT-PCR analysis revealed that overexpression of these three transcription factors induced the up-regulation of key structural genes in the AG biosynthetic ...
[85]
Identification of oxidosqualene cyclases associated with saponin ...
Mar 26, 2022 · β-Amyrin and cycloartenol synthases in the medicinal plant A. membranaceus were characterized. •. They contribute to the biosynthesis of ...
[86]
Integrated Transcriptomics and Metabolomics Analysis Reveals the ...
Jan 30, 2024 · Identification of oxidosqualene cyclases associated with saponin biosynthesis from Astragalus membranaceus reveals a conserved motif important ...
[87]
The Genome of Undifilum oxytropis Provides Insights into ...
Aug 1, 2016 · Undifilum oxytropis is a fungal endophyte of locoweeds. It produces swainsonine, which is the principal toxic ingredient of locoweeds.
[88]
The Biosynthesis Pathway of Swainsonine, a New Anticancer Drug ...
Undifilum oxytropis isolated from locoweeds, the plant pathogen Slafractonia leguminicola, and the insect pathogen Metarhizium anisopliae, produce swainsonine.
[89]
siRNA-Silencing of swnR gene greatly reduced biosynthesis of ...
Aug 24, 2025 · Current evidence suggests that lysine and L-pipecolic acid serve as common precursors and intermediates in the swainsonine biosynthesis of these ...
[90]
Integrating transcriptomics and metabolomics to characterise the ...
Our findings demonstrated that the expression of drought-responsive genes showed a strong stress-dose dependency. Analysis of backbone pathways of the ...
[91]
Biosynthesis and role of isoflavonoids in legumes under different ...
Drought and salinity stress. Aside from UV-B irradiation, isoflavonoids can also be induced as a response to other abiotic environmental stress factors.
[92]
Identification and Expression Analysis of Cytochrome P450 Genes ...
Jul 30, 2024 · Cytochromes P450 (P450s) are one of the largest enzymatic protein families and play critical roles in the synthesis and metabolism of plant ...
[93]
Anti-Aging Implications of Astragalus Membranaceus (Huangqi) - NIH
Astragalus membranaceus was used to promote immune function and as a tonic to build the stamina [29]. The aqueous extract of Astragali radix also has ...
[94]
Anticancer Mechanism of Astragalus Polysaccharide and Its ...
For example, a traditional Chinese medicine blend known as Bu Zhong Yi Qi Tang (BYD), which contains APS as a key ingredient, effectively reduced PD-L1 ...
[95]
Recent efficacy and long-term survival of Astragalus polysaccharide ...
Additionally, the incidences of leukopenia, thrombocytopenia, and fatigue in patients receiving the combined therapy of APS and GS were significantly lower than ...
[96]
Evaluating myelophil, a 30% ethanol extract of Astragalus ...
Jun 20, 2024 · Evaluating myelophil, a 30% ethanol extract of Astragalus membranaceus and Salvia miltiorrhiza, for alleviating fatigue in long COVID: a real- ...
[97]
Traditional Chinese herbal medicine at the forefront battle against ...
Sep 28, 2020 · ... coronavirus pneumonia (COVID-19): a randomized controlled clinical trial ... Astragalus membranaceus (16 times) (Zhang and Li, 2020). Another ...
[98]
A Preclinical Systematic Review and Meta-Analysis of Astragaloside ...
Jul 3, 2018 · Meta-analyses showed AS-IV can significantly decrease the myocardial infarct size and left ventricular ejection fraction, and increase shortening fraction ...
[99]
Effect of Astragalus membranaceus on left ventricular remodeling in ...
Jan 12, 2024 · This systematic review and meta-analysis revealed that the combination therapy of A. membranaceus with CT has more advantages than CT alone in improving LVR ...
[100]
The telomerase activator TA-65 elongates short telomeres and ... - NIH
In addition, we demonstrate that TA-65 is capable of increasing mTERT levels in some mouse tissues and elongating critically short telomeres when supplemented ...
[101]
ASTRAGALUS - Uses, Side Effects, and More - WebMD
Astragalus (Astragalus membranaceus) is a type of flowering plant. The root has been used for centuries in traditional Chinese Medicine (TCM).Missing: medieval | Show results with:medieval
[102]
Perennial Forage Species for Irrigated Pastures and Hay in New ...
Cicer milkvetch is adapted to a wide range of soil textures, pH, and salinity conditions. While cicer milkvetch has the advantage of being non-bloating, it has ...
[103]
Forage legumes - University of Minnesota Extension
Guide to forage legumes in Minnesota: Features, uses and varieties of clovers, birdsfoot trefoil, crown vetch, cicer milkvetch and alfalfa.
[104]
Forage Legumes for Oklahoma - OSU Extension
Companion crops may be useful, though, to help control wind erosion on sandy sites. ... Cicer milkvetch (Astragalus cicer). Cicer milkvetch is a long-lived, warm ...
[105]
[PDF] Species Selection and Establishment for Irrigated Pastures in New ...
longer rest (45-60 days) period, cicer milkvetch might perform satisfactorily. The seeding rate for monoculture cicer milkvetch is 5 to 8 pounds per acre.
[106]
[PDF] Lutana' cicer milkvetch - Natural Resources Conservation Service
Lutana is of proven value in controlling erosion and improving soil quality on infertile, disturbed, or critical areas. It may also be used in wildlife food ...Missing: Plains | Show results with:Plains
[107]
Winter Beauty in the Rock Alpine Garden | Denver Botanic Gardens
Dec 21, 2009 · Still on the spiny trail is Astragalus angustifolius from Greece ... Leaving the spiky theme we move on to saxifrages which sharing the theme with ...
[108]
Plant of the Week – Acantholimon - Harlequins Gardens
Jul 2, 2024 · For the first time, we also have a few Astragalus angustifolius (Narrow-leafed Milk-vetch) – another rare and choice evergreen sub-shrub that is ...
[109]
Cicer Milkvetch – A Non-bloat-inducing Forage Legume
Aug 22, 2015 · Additionally, it is a species that allows for wildlife and has potential for soil erosion control and reclamation of disturbed lands because of ...Missing: Great | Show results with:Great
[110]
Astragalus cicer (Chickpea Milk-vetch) - Minnesota Wildflowers
Chickpea Milk-vetch is a relatively new weed in Minnesota. Like its relative Crown Vetch, it has been promoted as a good plant for erosion control.
[111]
A swainsonine survey of North American Astragalus and Oxytropis ...
Swainsonine has been detected in 19 Astragalus and 2 Oxytropis species in North America by thin layer chromatography, gas chromatography-mass spectrometry ...
[112]
Production of the alkaloid swainsonine by a fungal endophyte in the ...
Oct 25, 2013 · Recent research has shown that in Astragalus and Oxytropis species swainsonine is produced by a fungal endophyte belonging to the Undifilum genus.
[113]
Locoweed - Guide to Poisonous Plants
Locoweed, also known as white point-locoweed, is a perennial plant with white, pea-like flowers. It is poisonous due to swainsonine, even when dried.
[114]
Spatial Imaging, Speciation, and Quantification of Selenium in the ...
Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves ...
[115]
Astragalus Bisulcatus - an overview | ScienceDirect Topics
The syndrome “blind staggers” in livestock has also been associated with the consumption of selenium in accumulator plants. Characteristics of the syndrome are ...
[116]
Toxicological investigations on Astragalus hamosus ... - ResearchGate
978). Toxic signs of nitro poisoning in small ...
[117]
3-Nitropropionic acid and 3-nitro-1-propanol in species of Astragalus
... Nitropropionic Acid in Forages Poisonous to Livestock. Go to Citation ... Toxic nitro compounds in Astragalus species. Go to Citation Crossref Google ...Missing: complanatus | Show results with:complanatus
[118]
A Guide to the Common Locoweeds and Milkvetches of New Mexico
About 263 species of Astragalus from throughout North America contain aliphatic nitro compounds toxic to livestock (Cheeke and Shull, 1985). However, the number ...
[119]
[PDF] Locoweed Poisoning in Livestock - University of Arizona Journal
Locoweed poisoning is estimated to cause $100 million in losses annually. It should be noted that locoism is not limited to North America; numerous Astragalus, ...
[120]
[PDF] Locoweed Toxicity, Ecology, Control, and Management - USDA ARS
Some species of Astragalus and Oxytropis contain the indolizidine alkaloid swainsonine that causes the poisoning syndrome known as locoism. Swainsonine is ...
[121]
Reproductive Toxicities Caused by Swainsonine from Locoweed in ...
Natural and experimental long-term ingestion of locoweed causes serious dysfunction in the reproduction of livestock (cattle, sheep, horses, and goats) in both ...Missing: $100 | Show results with:$100
[122]
Selenium Toxicosis in Animals - Toxicology - Merck Veterinary Manual
Chronic selenosis, often termed alkali disease, is associated with loss of hair on the mane and tail, hoof deformities, and decreased reproductive performance.
[123]
Department of Animal Science - Plants Poisonous to Livestock
"Blind staggers" occurs when animals ingest water-soluble selenium compounds naturally found in accumulator plants. Toxicity from eating plants or grain with ...
[124]
Astragalus - LiverTox - NCBI Bookshelf - NIH
Apr 10, 2019 · Astragalus is a traditional Chinese herbal medicine used as a general tonic and treatment for many conditions including diarrhea, upper ...
[125]
Astragalus: Usefulness and Safety | NCCIH
Sometimes combined with other herbs, astragalus has been promoted as a dietary supplement for many conditions, including upper respiratory infections, allergic ...
[126]
Selenium Toxicity - News-Medical
Potential sources of toxic levels of selenium include Astragalus and copper ingestion.
[127]
Locoweed Poisoning of Horses | New Mexico State University
Swainsonine, an indolizidine alkaloid, is the toxic principle responsible for the pathological changes in body tissues that lead to the disease known as ...
[128]
Swainsonine Poisoning
Swainsonine, found in some Astragalus plants, causes locoism, birth defects, reproductive issues, and heart failure in livestock. Locoism includes aggression ...
[129]
A Guide to Locoweed: Poisoning and Management
Livestock poisoned by chronic ingestion of large amounts of swainsonine develop a condition known as locoism and reported most often in cattle, sheep and horses ...
[130]
On the nature of selenium toxicity and carcinostatic activity - PubMed
Selenium toxicity was first confirmed in 1933 to occur in livestock that consumed plants of the genus Astragalus, Xylorrhiza, Oonopsis, and Stanleya in the ...
[131]
(PDF) Rarity in Astragalus: a California Perspective - ResearchGate
Sep 25, 2017 · The California Native Plant Society lists 51 Astragalus taxa (35% of the native Astragalus taxa) as rare, threatened, or endangered (RTE).Missing: albicaulis | Show results with:albicaulis
[132]
[PDF] Astragalus claranus (Clara Hunt's milkvetch) - 5-Year Review - ECOS
Habitat destruction and modiﬁcation due to urbanization and competition from invasive plant species pose the most signiﬁcant threats to this species.Missing: critically | Show results with:critically
[133]
Life history and demographic features of Astragalus nitidiflorus, a ...
Astragalus nitidiflorus is an endangered perennial, but short-lived legume of SE Spain, which has been re-found after 100 years. To identify possible weak ...
[134]
Effects of Agricultural Use on Endangered Plant Taxa in Spain
Nov 2, 2021 · 3.2.2. Taxa Endangered by Crop Intensification. Seven plants are threatened by agricultural intensification. Of these, Astragalus nitidi-.
[135]
Astragalus jaegerianus | NatureServe Explorer
Other threats include habitat destruction from dry wash gold mining, other mining activities, rock and mineral collecting, off-road vehicle activity, and ...
[136]
[PDF] Astragalus jaegerianus (Lane Mountain milk-vetch) 5-year Review
Aug 14, 2023 · New mining claims can be established and mining at levels greater than casual use can be approved through the approval of a Plan of ...
[137]
Threatened Species Status for Chapin Mesa Milkvetch and ...
Sep 17, 2020 · Climate change models forecast warmer temperatures and a decrease in precipitation, or change ... (c) Astragalus schmolliae (Chapin Mesa ...
[138]
[PDF] Long-term Population Trends and Environmental Attributes of the ...
The species is considered highly vulnerable to climate change (Handwerk et al. ... schmolliae (Astragalus schmolliae. C.L. Porter). Colorado Natural Heritage ...
[139]
https://www.federalregister.gov/documents/2022/02/02/2022-02041/endangered-and-threatened-wildlife-and-plants-threatened-species-status-for-chapin-mesa-milkvetch
[140]
The Effects of Long-Term Drought on Host Plant Canopy Condition ...
Apr 1, 2010 · Astragalus jaegerianus Munz (the Lane Mountain milkvetch) is a federally endangered species that exists in only four fragmented populations ...
[141]
Sentry milk-vetch: endangered plant - Grand Canyon National Park ...
Yet within this huge area containing ecosystems ranging from forest to desert, there is only one federally-listed endangered plant: sentry milk-vetch ( ...
[142]
Collaborative conservation pays off for one of Idaho's rarest plant ...
Conservation measures are being implemented as part of that agreement, including exclosure fences around particularly sensitive Packard's milkvetch occurrences, ...
[143]
[PDF] Astragalus danicus Retz. Purple Milk-vetch Seed harvest ...
The approximate dry weight of 1000 seed is. 1.262g. Collections conserved at the Millennium Seed Bank were harvested between early July and late August.
[144]
Pyne's Ground-plum (Astragalus bibullatus)
The primary focus of this bed is to grow Astragalus bibullatus plants for fruit/ seed collection. These seeds are then used in germination studies, seed banking ...
[145]
Special Collections: Millennium Seed Bank Project - Wildflower Center
Millennium Seed Bank Project. List of Texas species that were collected ... Astragalus crassicarpus, Groundplum Milkvetch Ground Plum. 12 images. Asclepias ...
[146]
[PDF] Mancos Milkvetch (Astragalus humillimus) Status Assessment and ...
Of these, only one species, Astragalus humillimus, is also federally listed as endangered under the U.S. Endangered Species Act. Astragalus humillimus was ...
[147]
Peirson's Milkvetch - California Department of Fish and Wildlife
This species is also listed as threatened under the federal Endangered Species Act. Peirson's milkvetch is a member of the legume family (Fabaceae) and is an ...Missing: IUCN | Show results with:IUCN
[148]
Recovery Plan for Holmgren milk-vetch (Astragalus holmgreniorum ...
Sep 29, 2006 · These species are federally listed as endangered under the Endangered Species Act of 1973, as amended (Act).
[149]
Life‐history strategy and extinction risk in the warm desert perennial ...
This study of Astragalus holmgreniorum examines its adaptations to the warm desert environment and whether these adaptations will enable it to persist.
[150]
[PDF] Astragalus ampullarioides (Shivwits Milk-Vetch) - ECOS
The plant has a raceme inflorescence with, typically, 6 to 16 flowers. The peduncle, which is. 0.8-3.6 in.(2.0-8.5 cm) long, rises directly from the root crown ...Missing: morphology | Show results with:morphology
[151]
Service Announces Sentry Milk-Vetch Recovery Plan
Apr 10, 2025 · The US Fish and Wildlife Service has approved the revised recovery plan for the endangered plant, sentry milk-vetch.
[152]
Endangered and Threatened Wildlife and Plants; Removing Deseret ...
Oct 18, 2018 · Livestock Grazing and Trampling In contrast to many species of Astragalus, this species apparently is not toxic to livestock, and is palatable ...
[153]
[PDF] CONSERVATION AGREEMENT AND STRATEGY - Regulations.gov
May 20, 2022 · This document is an interagency Conservation Agreement and Strategy (CAS) for Cisco, stage station, and Isely's milkvetch within Utah.
[154]
[PDF] astragalus-anisus-roadside-bmps.pdf
One of the biggest conservation issues for this imperiled plant species is the lack of awareness of its existence and status. Avoiding or minimizing impacts to ...