Shiso
Shiso, scientifically known as Perilla frutescens var. crispa, is an aromatic annual herb belonging to the Lamiaceae (mint) family, native to the Himalayas and Southeast Asia, prized for its distinctive crinkled leaves that come in green or purple varieties and emit a musky, mint-like fragrance.[1] The plant typically grows 1 to 3 feet tall and 0.25 to 1.5 feet wide, featuring ovate, serrate-edged leaves and spikes of small, white, bell-shaped flowers that bloom from late summer to fall, with seeds that can be harvested for oil production.[1] Cultivated primarily in East Asian countries like Japan, Korea, and China, shiso is often grown as an ornamental or edible plant but can become invasive in temperate regions such as parts of the United States due to its aggressive self-seeding.[1] In culinary traditions, shiso leaves are versatile, used fresh as a garnish for sushi, sashimi, and salads, pickled for longer storage, or incorporated into dishes like tempura and soups to impart a unique basil-cumin flavor profile.[2] The seeds are pressed (often after roasting) to produce perilla oil, a staple in Korean and Japanese cooking rich in alpha-linolenic acid (an omega-3 fatty acid), or used whole to add nutty depth to stews and marinades.[1] Beyond the kitchen, Perilla frutescens serves as a homologous food-medicine plant in traditional East Asian systems, where its leaves, stems, and seeds are employed to alleviate conditions such as colds, asthma, allergies, and digestive issues owing to bioactive compounds like rosmarinic acid and flavonoids.[3] Pharmacological research highlights P. frutescens's potential anti-inflammatory, antioxidant, antibacterial, and hepatoprotective effects, supported by its chemical profile including essential oils, polyphenols, and terpenoids, though it poses toxicity risks to livestock if ingested in large quantities.[4][1]Names and etymology
Common names
Perilla frutescens is known by numerous common names reflecting its cultural significance in Asian cuisines and herbal traditions, with variations often tied to specific varieties or uses. In English-speaking regions, particularly in North America and Australia, it is frequently called beefsteak plant due to the reddish-purple hue of some leaves resembling raw meat, perilla mint for its aromatic qualities, or Chinese basil as an approximation of its flavor profile.[5][6][7] In Japan, where it is a staple herb, the primary common name is shiso (紫蘇), derived from the Chinese characters for purple perilla; green-leaved varieties are termed ao-shiso (青紫蘇), while red or purple types are known as aka-shiso (赤紫蘇) or chirimen-shiso (縮緬紫蘇) for their crinkled leaves.[8][9] Korean nomenclature distinguishes uses, with kkaennip (깻잎) commonly referring to the fresh leaves employed in wraps and dishes, and deulkkae (들깨) denoting the plant or its oil-rich seeds.[10][8] In China, its native origin, the plant is called zisu (紫苏) or zisuye (紫苏叶) for the leaves, highlighting its role in traditional medicine and as a seasoning.[11][3] In Vietnam, it is known as tía tô, used similarly in culinary and medicinal applications. Additional regional names include purple shiso and Japanese basil in horticultural contexts, rattlesnake weed in some wild settings, and wild sesame or summer coleus in broader English usage, though these are less specific to culinary applications.[1][12][7]Etymology
The Japanese term shiso is a romanization of シソ (shiso), written in kanji as 紫蘇, where 紫 (shi) means "purple" and 蘇 (so) denotes perilla, reflecting the plant's often purplish foliage and its historical association with the herb in East Asian nomenclature. This name derives directly from the Chinese zǐsū (紫蘇), literally "purple perilla," which has been used since ancient times to refer to Perilla frutescens.[13] The genus name Perilla originates from the Latin pera, meaning "bag" or "wallet," alluding to the pouch-like fruiting calyx that encloses the seeds.[5] The specific epithet frutescens is Latin for "shrubby" or "bushy," describing the plant's upright, branching growth habit.[5] In English, it is commonly known as beefsteak plant due to the deep red varieties' leaves resembling raw beefsteak.[1] Other regional names include kkaennip (sesame leaf) in Korean, evoking a superficial resemblance to sesame despite no close relation, and tía tô in Vietnamese, derived from the same Sino-Vietnamese roots as the Chinese term.[13]Origins, history, and distribution
Origins and domestication
Perilla frutescens, commonly known as shiso, is native to the mountainous regions of East and Southeast Asia, including the Himalayas, northeast India, China, and parts of Nepal, where it grows at elevations up to 1,200 meters.[14][1][15] The plant's wild or weedy forms are still found in these areas, suggesting its natural distribution predates human intervention, though the exact wild ancestor remains unidentified.[16] Domestication is thought to have begun in the region spanning northeast India to China, with early selection likely focusing on its aromatic leaves and oil-rich seeds for culinary and medicinal purposes.[17] In China, Perilla frutescens has been cultivated for over 2,000 years, marking it as one of the earliest domesticated herbs in the region. The oldest documented references to its medicinal use appear in the Miscellaneous Records of Famous Physicians (Mingyi Bielu), compiled by Tao Hongjing in the early 6th century AD (drawing on earlier Han-era knowledge), which includes it among approximately 730 medicinal substances for its therapeutic properties.[3][18] By the Ming Dynasty, comprehensive works like the Compendium of Materia Medica (Bencao Gangmu) detailed its dual use as both food and medicine, indicating widespread domestication and selective breeding for enhanced flavor and yield.[3] This long history of cultivation in China underscores its role as a staple in traditional East Asian agriculture. Archaeological evidence supports early domestication beyond China, with carbonized seeds discovered at the Baekya site in southwestern Korea, dating to approximately 1000 BCE during the Mumun period. These findings, totaling about 37 grams from a pit dwelling, represent the earliest direct proof of Perilla storage and likely cultivation in the Korean peninsula, implying human management and possible independent or diffused domestication processes in Northeast Asia.[19] Similar macrofossil evidence from Jomon-period sites in Japan further illustrates the plant's rapid spread and adaptation through human activity across the region by the late prehistoric era.[20]Historical development
Perilla frutescens, commonly known as shiso, has been cultivated in China for over 2,000 years, initially valued for its medicinal properties and as a food source in traditional Chinese medicine.[3] Archaeological evidence from the Korean Peninsula indicates early cultivation during the Mumun period (ca. 1500–300 BC), with carbonized seeds and pottery impressions found at multiple sites, suggesting it was stored and used as a crop alongside cereals and legumes by around 1000 BC.[21] These findings point to domestication in East Asia, likely originating from wild populations in the mountainous regions of China and the Himalayas.[14] By the 7th century AD, widespread cultivation had established in its native East Asian range, where the plant was grown for both its aromatic leaves and oil-rich seeds.[15] The plant reached Japan between the 8th and 9th centuries, initially introduced for seed oil production rather than culinary leaves, as documented in early Japanese records.[17] Over time, selective breeding in Japan led to the development of distinct varieties, such as Perilla frutescens var. crispa (green and red shiso) for edible leaves used in cuisine and var. frutescens (egoma) for oil, integrating it into Shinto rituals and everyday dishes by the Heian period (794–1185 AD).[8] In Korea, shiso (kkaennip) became integral to local agriculture before the Unified Silla era (668–935 AD), with expanded uses in fermentation and seasoning that paralleled its role in Chinese zi su preparations.[17] Its spread to Southeast Asia, including Vietnam, occurred through trade routes, where it adapted as a garnish in soups and wraps, reflecting broader cultural exchanges in the region by the medieval period.[8] By the 19th century, European botanists documented the plant during Asian explorations, leading to limited introductions in the West, though its primary historical development remained centered in East Asia.[14]Geographical distribution
Shiso (Perilla frutescens) is native to East and Southeast Asia, with its wild range originating in the Himalayan foothills and extending through mountainous regions of India, Nepal, southern and eastern China, Korea, Japan, and into Indochina and Indonesia. This distribution spans semi-tropical to temperate elevations up to 1,200 meters, where the plant thrives in moist, disturbed habitats such as forest margins and hillsides.[22][14][15] The species is widely cultivated within its native range for culinary, medicinal, and oilseed purposes, with primary production centered in China, Japan, South Korea, and Vietnam. In these countries, it is grown as an annual crop in fertile, well-drained soils under full sun to partial shade, supporting both traditional farming and commercial agriculture. Korea stands out for its extensive cultivation, reflecting the plant's integral role in local diets and industries. Smaller-scale production occurs across other parts of Southeast Asia and northeast India.[5][23][24] Beyond Asia, P. frutescens has been introduced globally as an ornamental and culinary herb, often escaping cultivation to naturalize in temperate and subtropical regions. In North America, it is established across 24 U.S. states, particularly in the eastern and central regions like Missouri, Virginia, and Tennessee, where it invades roadsides, ditches, and riparian zones, sometimes disrupting native ecosystems. In Europe, it appears in at least 13 countries, including the United Kingdom, Germany, and Italy, typically in anthropogenic habitats. The plant's adaptability has led to its presence in 62 countries worldwide, though it remains most abundant in its Asian homeland.[25][23][24]Botanical description
Morphology
Perilla frutescens is an erect, annual herbaceous plant in the Lamiaceae family, typically growing to a height of 0.6 to 1.8 meters, though it can reach up to 2 meters under favorable conditions, with a bushy, freely branching habit.[26][5][27] The stems are square in cross-section, characteristic of the mint family, and range from green to purple, often covered with short, soft hairs (villose); they feature four parallel longitudinal grooves and can persist as dried stalks through winter.[26][1][15] The leaves are opposite, simple, and broadly ovate to orbicular in shape, measuring 7–13 cm long and 4.5–10 cm wide, with coarsely serrate or dentate margins, mucronate tips, and rounded to cuneate bases.[26][1] They are often wrinkled, particularly in cultivated varieties, and pilose on both surfaces, with colors varying from green to deep purple, sometimes bicolored; the undersides may show prominent venation with 7–8 pairs of lateral veins that are raised.[26][5][28] Petioles are flat, villose, and 2–7 cm long, contributing to the plant's aromatic quality when crushed.[26][27] Flowers are small, bilabiate (two-lipped), and white to pale purple, borne in dense, terminal or axillary spike-like racemes or corymbs up to 10 cm long, emerging from leaf axils in late summer to fall.[1][5] The calyx is bilaterally symmetrical, accrescent in fruit, with fused carpels forming a schizocarp. Fruits are subglobose nutlets, reticulate, grayish-brown, approximately 1.5 mm in diameter, containing seeds that are globular, 1–2 mm across, and colored white to dark brown, weighing about 4 grams per 1000 seeds.[26][14][9]Varieties
Perilla frutescens encompasses several botanical varieties, with the primary ones being var. frutescens and var. crispa, distinguished by leaf morphology, coloration, and cultivation status.[14] Var. frutescens, often referred to as the wild form or wild sesame, features leaf blades that are crenate-serrate to low-serrate, typically green on the adaxial surface but sometimes purple overall; it serves as the main source for perilla seed oil, valued in Korean cuisine and industrial applications like wood finishing.[14] This variety is more commonly naturalized in regions outside its native range, including parts of North America.[14] Var. crispa, known commonly as shiso in Japanese contexts, exhibits prominently serrate leaf margins with long, sharp teeth and crinkled leaves that are typically green or purple in color; it is primarily cultivated as a culinary herb across East Asia, particularly in Japan and Korea.[29] Within var. crispa, two key forms are recognized based on leaf color: f. viridis (green shiso or aojiso), with green leaves on both sides, white flowers, and purple stems, used broadly in fresh preparations and garnishes; and f. purpurea (red shiso or akajiso), characterized by deep purple-red leaves due to high anthocyanin content, often employed for pickling, dyeing, and flavoring in umeboshi plums.[17][29] These forms were historically treated as separate taxa but are now classified under var. crispa.[29] Additional varieties, such as var. hirtella, occur in specific regions like southern Japan and Korea, featuring hairy stems and leaves similar to var. frutescens but with more pronounced pubescence; however, these are less commonly cultivated and primarily noted in wild populations.[30] Overall, distinctions among varieties emphasize adaptations for culinary, medicinal, and ornamental purposes, with var. crispa dominating horticultural use due to its aromatic foliage and visual appeal.[31]Cultivation
Growing requirements
Shiso, or Perilla frutescens, thrives in warm climates and is typically cultivated as an annual in temperate regions, with hardiness suited to USDA zones 3 through 10 as an annual, though it behaves as a perennial in zones 10 through 11.[32] The plant prefers temperatures above 18°C (64°F) for optimal growth and is frost-sensitive, requiring protection or indoor starting in cooler areas to avoid damage below 10°C (50°F).[33] It adapts well to semi-tropical environments at higher altitudes with moderate annual temperatures (around 15–25°C) and suitable humidity levels, making it resilient in regions like parts of East Asia.[34] For light exposure, shiso performs best in full sun to partial shade, receiving at least 6 hours of direct sunlight daily to promote robust leaf production and vibrant coloration, though it tolerates some afternoon shade in hotter climates to prevent scorching.[1] In shaded or semi-shaded conditions, such as woodland edges, it can still grow vigorously, often reaching heights of 1.5–1.8 meters in fertile spots.[35] The plant is highly adaptable to various soil types but favors well-drained, loamy soils with a pH range of 5.5 to 7.5; it can handle poor, sandy, or clay soils as long as drainage is adequate to prevent root rot.[36] Rich, organic matter-enriched soils enhance growth, but shiso demonstrates notable tolerance to drought and heat once established, requiring only average moisture without excessive watering.[1] Watering should be consistent during establishment, keeping soil evenly moist but not waterlogged, with reduced frequency in mature plants due to its drought resistance; overwatering can lead to leggy growth or disease susceptibility.[37] In cultivation, shiso benefits from spacing of 30–45 cm between plants to allow air circulation and prevent overcrowding, which supports healthy development in garden beds, containers, or borders.[32] Overall, its low-maintenance nature and adaptability make it suitable for both novice and experienced gardeners in warm-season plantings.[38]Propagation and care
Shiso (Perilla frutescens) is primarily propagated from seeds, which require light for germination and should be sown shallowly, about 1/4 inch deep, in moist soil. To enhance germination rates, soak seeds in water for 24 hours prior to planting; germination typically occurs within 7 to 14 days at soil temperatures of 70–75°F (21–24°C). Seeds can be started indoors 4–6 weeks before the last frost or directly sown outdoors after the danger of frost has passed, in spring when soil temperatures reach at least 55°F (13°C).[39][40][32] Stem cuttings provide an alternative propagation method, particularly for maintaining specific varieties. Take 4–6 inch cuttings from healthy stems in spring or summer, remove lower leaves, and root them in moist perlite or a well-draining medium under high humidity; roots form in 4–6 weeks. Cuttings root more reliably than seeds for some ornamental cultivars and help avoid issues with seed sterility in certain hybrids.[38][41] For optimal growth, plant shiso in well-draining, fertile soil with a pH of 5.5–7.0, similar to that suitable for basil. It thrives in full sun to partial shade, receiving at least 6 hours of direct sunlight daily, though it tolerates some afternoon shade in hotter climates to prevent leaf scorching. Space plants 6–12 inches apart in garden beds or containers to allow for their bushy habit, which can reach 1–2 feet tall and wide. As an annual in temperate zones, it benefits from being grown as a container plant, which allows overwintering indoors in cooler regions.[39][32][1] Care involves consistent moisture without waterlogging; water regularly to keep soil evenly moist, especially during dry spells, but allow the top inch to dry between waterings to prevent root rot. Fertilize lightly with a balanced, diluted liquid fertilizer every 4–6 weeks during the growing season, or incorporate compost into the soil at planting. Pinch back growing tips regularly to promote bushier growth and delay flowering, which can make leaves tougher; this also helps control self-seeding, as shiso readily produces wind-dispersed seeds that can become invasive if unchecked. In fall, harvest before frost by cutting stems or individual leaves.[39][37][1] Shiso is relatively low-maintenance and pest-resistant due to its aromatic oils, but monitor for aphids or spider mites, which can be controlled with insecticidal soap or neem oil. Fungal issues like powdery mildew may arise in humid conditions with poor air circulation; ensure proper spacing and avoid overhead watering to mitigate this. It is hardy in USDA zones 3–10 as an annual but can be perennial in zones 10–11 with mild winters.[39][32][35]Regional production
Shiso (Perilla frutescens var. crispa) is cultivated mainly in East Asia for its edible leaves, with additional production of the oilseed variety (var. frutescens) across broader Asian regions. Major producing countries include China, Japan, Korea, Vietnam, and India, where it is grown for culinary, medicinal, and oil extraction purposes.[17][9] In Korea, perilla is a key crop for both leaves and seeds, with the country serving as the world's largest producer of perilla seed oil. As of marketing year 2023/24, annual seed production was 48,000 metric tons from 41,000 hectares. Global production was estimated at approximately 300,000 metric tons in 2021. Leaf production is concentrated in southern regions, notably Miryang city, which supplies 43.6% of the national perilla leaf harvest, supported by abundant clean groundwater ideal for herb cultivation.[42][43][44][45] Japan focuses primarily on shiso leaf cultivation for fresh market use. In 2015/16, approximately 6,708 tonnes were produced for direct consumption, distributed across temperate and subtropical prefectures suitable for year-round greenhouse and open-field growing. Regional hubs include areas with mild climates that favor the plant's rapid growth cycle of 60–90 days.[42][46] In China, shiso originates from southern mountainous areas and is grown extensively in provinces like Yunnan and Sichuan for both leaves and seeds, contributing to local spice and oil markets, though comprehensive yield data remains sparse.[17] India's production centers on the northeastern hill regions, including Manipur, Meghalaya, and Nagaland, where diverse landraces of the oilseed variety thrive in subtropical highlands up to 2,000 meters elevation, supporting traditional farming systems with yields adapted to local monsoon patterns.[9][47] Southeast Asian countries like Vietnam and parts of Myanmar cultivate shiso on smaller scales in lowland and mid-elevation areas, often intercropped with rice or vegetables, emphasizing its role in regional cuisines and herbal remedies.[17]Culinary uses
East Asian cuisine
In Japanese cuisine, shiso (Perilla frutescens var. crispa) is prized for its distinctive minty, basil-like aroma and is commonly used as a fresh herb or garnish. Green shiso leaves often accompany sushi and sashimi, where they provide a refreshing contrast to fatty fish, or are finely chopped into salads, tempura batter, and noodle dishes like soba. Red shiso (akajiso) serves primarily as a natural food coloring, infusing umeboshi plums with their signature vibrant hue during pickling, and is occasionally steeped to make a ruby-red rice vinegar condiment known as umezu. The leaves can also be deep-fried as tempura or layered in onigiri rice balls for added flavor.[2][48][49] In Korean cuisine, perilla leaves, known as kkaennip, are versatile staples valued for their minty, basil-like flavor with hints of anise. They are frequently used whole as ssam wraps to encase grilled meats like bulgogi or samgyeopsal during barbecues, balancing richness with their earthy notes, or stuffed with rice and vegetables for side dishes. Shredded kkaennip adds minty freshness to namul (seasoned vegetable salads), bibimbap, or soups such as doenjang guk, while pickled versions (kkaennip jangajji) serve as tangy banchan. Ground perilla seeds (deulkkae garu) contribute a toasted, nutty depth to stews, marinades, and even perilla seed oil for dressings. Steamed preparations like kkaennipjjim highlight the leaves' tenderness when seasoned simply with soy sauce and sesame oil.[50][51][10][52] Chinese culinary traditions incorporate perilla (zǐ sū) leaves more subtly, often as an aromatic seasoning or wrapper in regional dishes. In northern China, the larger, milder leaves function as edible wraps for meats or dumplings, similar to cabbage, imparting a mild spice to stir-fries and steamed preparations like pork ribs or fish heads. Hunan cuisine employs them to flavor poached shrimp or grilled fish, where their sweet-spicy profile cuts through heavier sauces. The leaves are also combined with ginger or lotus leaves to brew herbal teas, or used fresh in salads and vegetable dishes for a basil-like enhancement. Perilla seed oil remains a staple for cooking, valued for its high smoke point and nutty taste in everyday stir-fries.[49][3][53]Southeast Asian cuisine
In Vietnamese cuisine, Perilla frutescens, locally known as tía tô, serves as a key aromatic herb, prized for its peppery, mint-like flavor with hints of anise and basil. The fresh leaves are commonly incorporated raw into salads (gỏi), spring rolls (gỏi cuốn), cold noodle bowls (bún), and soups such as phở, where they provide a refreshing contrast to richer elements. They are also employed as wraps for grilled meats and fish preparations, enhancing dishes like beef skewers (bò nướng) by adding herbal depth and aiding in the balance of flavors.[17][54] In Thai cuisine, Perilla frutescens goes by the name nga-mon and functions as an aromatic vegetable, contributing its distinctive herbaceous notes to a range of dishes. It appears in southern Thai specialties, such as herbal rice salads (yam) and curries like stingray stew, where the leaves are added fresh or lightly cooked to impart subtle minty and spicy undertones. The herb's versatility allows it to substitute for similar greens in traditional recipes, supporting its integration into everyday meals focused on fresh, bold flavors.[55][56] While Perilla frutescens originates from Southeast Asia and is cultivated across the region, its culinary prominence is more limited in countries like Indonesia and Malaysia compared to Vietnam and Thailand, where it occasionally features in local herb blends or as a minor garnish in fusion dishes rather than as a core ingredient.[17]Global and other uses
In Western fusion cuisine, shiso has emerged as a versatile herb, often substituting for basil or mint due to its minty, citrusy, and slightly anise-like profile. Chefs incorporate fresh shiso leaves into pestos, where they blend with nuts, garlic, and olive oil to create a vibrant green sauce for pastas or grilled vegetables, offering a brighter, more aromatic alternative to traditional basil pesto.[2] Similarly, chopped shiso enhances salads, such as those with avocado, grapefruit, or heirloom tomatoes, adding a refreshing crunch and flavor contrast. Shiso's adaptability extends to cocktails, particularly in North American and European bar scenes, where it infuses beverages with its distinctive herbaceous notes. A popular application is the shiso mojito, a variation on the classic Cuban cocktail that replaces or supplements mint with muddled shiso leaves, rum, lime juice, and soda for a tropical, slightly spicy twist.[57] This preparation highlights shiso's role in modern mixology, appearing in recipes from upscale lounges to home bartending guides.[58] Beyond savory and drink applications, shiso appears in innovative desserts in global kitchens, such as sorbets, ice creams, or fruit-based confections, where its subtle sweetness and aroma complement berries or citrus. In broader Western experimentation, shiso oil or infused butters are drizzled over grilled meats, fish, or pizzas, bridging Asian influences with European and American grilling traditions.[2] These uses reflect shiso's growing availability in farmers' markets and specialty grocers outside Asia, fostering creative, cross-cultural culinary expressions.[49]Medicinal uses
Traditional applications
In traditional Chinese medicine (TCM), Perilla frutescens, commonly known as zi su, has been utilized for over 2,000 years to treat respiratory and digestive ailments. The leaves are primarily employed to dispel pathogenic wind, promote qi circulation, and alleviate symptoms of wind-cold invasion, such as colds, coughs with phlegm, chest tightness, and dyspnea.[59] Preparations often involve decoctions or infusions of the fresh or dried leaves, sometimes combined with other herbs like ginger for enhanced warming effects. The seeds, referred to as zi su zi, are used to lubricate the intestines, resolve food stagnation, and address constipation, abdominal pain, and vomiting due to dietary indiscretions.[3] In Japanese Kampo medicine, Perilla frutescens (referred to as egoma or shiso) shares similar applications, with the leaves valued for their aromatic properties to treat mental stress, nausea, and respiratory issues like asthma and influenza prevention. Historical records document its use as a calming agent to soothe the mind and relieve cold symptoms. The entire plant, including stems, may be infused to manage abdominal pain and promote digestion.[60] Korean traditional medicine (Hanbang) employs Perilla frutescens for comparable purposes, focusing on its antiemetic and antitussive effects. The leaves and seeds are traditionally used to treat coughs, lung afflictions, and gastrointestinal discomfort, often in teas or poultices to reduce inflammation and expel phlegm. Ethnomedicinal records highlight its role as an analgesic for pain relief, particularly in the stems for conditions like headaches and joint discomfort.[13] Beyond East Asia, in Indian traditional systems, the plant's stem has been historically applied as an analgesic and to prevent miscarriage, reflecting its broader ethnomedicinal versatility across regions. Overall, these applications underscore Perilla frutescens's role as a "food homologous" herb, where medicinal uses overlap with culinary practices to support holistic health.[13]Modern pharmacological research
Modern pharmacological research on Perilla frutescens (shiso) has identified a wide array of bioactive compounds, including phenolic acids (e.g., rosmarinic acid), flavonoids (e.g., luteolin, apigenin), and monoterpenes (e.g., perillaldehyde, perillaketone), that underpin its therapeutic potential.[61] These compounds contribute to activities such as antioxidant, anti-inflammatory, antidiabetic, anticancer, and antimicrobial effects, often evaluated through in vitro, in vivo, and limited clinical studies.[62] Antioxidant properties are prominently featured, with leaf and seed extracts exhibiting potent free radical scavenging via DPPH and ABTS assays, attributed to high total phenolic content.[63] In vivo studies on rodent models show reduced oxidative stress markers like malondialdehyde in liver and kidney tissues following administration of ethanolic extracts.[61] Anti-inflammatory effects involve inhibition of pro-inflammatory mediators; for instance, rosmarinic acid suppresses NF-κB activation and lowers TNF-α and IL-6 levels in lipopolysaccharide-induced macrophage models.[64] Animal studies demonstrate reduced paw edema in arthritis models treated with perilla leaf extracts, comparable to standard drugs like indomethacin.[62] In antidiabetic research, perilla extracts improve glucose tolerance and insulin sensitivity in streptozotocin-induced diabetic rats, primarily through α-glucosidase inhibition and protection of β-cells from oxidative damage.[61] Anticancer investigations highlight compounds like isoegomaketone and perillaketone, which induce apoptosis in human leukemia and breast cancer cell lines via caspase-3 activation and mitochondrial membrane depolarization.[64] In xenograft mouse models, perilla extracts suppressed tumor growth without significant toxicity.[62] Antimicrobial activity targets pathogens like Staphylococcus aureus and Candida albicans, with essential oils showing minimum inhibitory concentrations of 0.5-2 mg/mL due to membrane disruption by perillaldehyde.[65] Antiviral effects against influenza and herpes viruses have been noted in cell-based assays.[61] Emerging areas include neuroprotective effects, where flavonoids enhance BDNF expression and reduce amyloid-β aggregation in Alzheimer's models, and cardiovascular benefits, with seed extracts lowering systolic blood pressure in hypertensive rats through vasodilation and anti-inflammatory pathways.[66][62] Anti-allergic research shows inhibition of histamine release from mast cells, supporting its use in atopic dermatitis management.[67] While preclinical evidence is robust, human clinical trials remain limited, emphasizing the need for further validation to translate these findings into therapeutic applications.[68]Safety and toxicity
Perilla frutescens is generally considered safe for human consumption in culinary and moderate medicinal amounts, but caution is advised. It may cause toxic sores if combined with certain foods like crucian carp. The plant contains perilla ketone, which is toxic to livestock and ruminants, causing pulmonary edema upon ingestion in large quantities, though no significant toxicity has been reported in humans at typical doses. Pregnant individuals should consult healthcare providers due to traditional uses suggesting potential effects on miscarriage prevention.[3][69]Biochemistry and nutrition
Chemical composition
Shiso (Perilla frutescens) contains a diverse array of bioactive compounds distributed across its leaves, seeds, and other parts, primarily including volatile oils, phenolic acids, flavonoids, anthocyanins, polysaccharides, and fatty acids. These components contribute to its aromatic profile, nutritional value, and potential health benefits.[3][61] The essential oils, mainly extracted from the leaves, are rich in monoterpenes and sesquiterpenes, with perillaldehyde, limonene, and perilla ketone as predominant volatiles. Gas chromatography-mass spectrometry (GC-MS) analyses have identified perilla ketone as the major component, averaging 43.34% of the total volatiles, followed by myristicin (16.3%) and β-caryophyllene (around 10%). Other notable volatiles include elemicin, apiole, and various alcohols, aldehydes, and esters, totaling over 40 compounds across nine chemical classes in leaf extracts.[70][71] Phenolic compounds, particularly abundant in the leaves, encompass phenolic acids such as rosmarinic acid, caffeic acid, and ferulic acid, alongside flavonoids like luteolin, apigenin, quercetin, and chrysoeriol. Rosmarinic acid is a key polyphenol, often comprising significant portions of the total phenolic content in green and red varieties. Red shiso leaves are distinguished by anthocyanins, including malonylated shisonin and cyanidin derivatives, which impart their pigmentation.[61][72][73] Seeds of P. frutescens are notable for their high oil content (35-45%), dominated by polyunsaturated fatty acids. Alpha-linolenic acid (ALA, 18:3 n-3) is the primary fatty acid, ranging from 54-64%, followed by linoleic acid (18:2 n-6) at 14-20%, oleic acid (18:1) at 15-20%, and minor saturated fatty acids like palmitic (5-7%) and stearic (1-3%). Polysaccharides and triterpenoids are also present in seeds and leaves, though in lower concentrations.[74][75][76]| Plant Part | Major Compound Classes | Key Examples |
|---|---|---|
| Leaves | Volatile oils | Perillaldehyde (up to 50%), perilla ketone (43%), limonene |
| Leaves | Phenolics/Flavonoids | Rosmarinic acid, luteolin, apigenin, quercetin |
| Leaves (red) | Anthocyanins | Shisonin, cyanidin-3-caffeoylglucoside-malonate |
| Seeds | Fatty acids | α-Linolenic acid (54-64%), linoleic acid (14-20%) |
| Seeds/Leaves | Polysaccharides/Triterpenoids | Various neutral and acidic polysaccharides; ursolic acid |
Nutritional value
Shiso leaves (Perilla frutescens) are a low-calorie herb offering a modest profile of macronutrients and micronutrients, making them a nutrient-dense addition to diets. Per 100 grams of raw fresh leaves, they typically contain about 47 calories, with 4.46 grams of protein, 0.5 grams of total fat (including 0.1 grams saturated fat), and 8.89 grams of carbohydrates, of which 5.69 grams are dietary fiber and 0 grams are sugars.[34] Sodium content is low at 1 mg per 100 grams.[78] In terms of vitamins and minerals, shiso leaves provide vitamin A (70% of the daily value from 630 µg RAE, primarily as β-carotene at 7,565 µg), supporting vision and immune function, and vitamin C (3% DV, 2.73 mg), which aids in collagen synthesis and antioxidant defense.[34] They also supply calcium (23% DV, 296 mg) for bone health, iron (11% DV, 1.91 mg) for oxygen transport, and potassium (421–500 mg, 9–11% DV) for electrolyte balance.[34][78][79] Compared to other leafy greens like spinach, shiso leaves exhibit higher levels of β-carotene and lutein, key carotenoids that contribute to eye health and antioxidant activity.[34] The following table summarizes key nutritional components per 100 grams of raw fresh shiso leaves:| Nutrient | Amount | % Daily Value* |
|---|---|---|
| Calories | 47 kcal | - |
| Protein | 4.46 g | 9% |
| Total Fat | 0.5 g | 1% |
| Carbohydrates | 8.89 g | 3% |
| Dietary Fiber | 5.69 g | 20% |
| Vitamin A | 630 µg RAE | 70% |
| Vitamin C | 2.73 mg | 3% |
| Calcium | 296 mg | 23% |
| Iron | 1.91 mg | 11% |