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Diosmin

Diosmin is a naturally occurring , chemically known as diosmetin 7-O-rutinoside, with the molecular formula C₂₈H₃₂O₁₅ and a molecular weight of 608.549 g/mol, primarily isolated from the pericarp and pulp of fruits such as , as well as from plants like figwort ( nodosa). First isolated in 1925, diosmin is widely utilized as a venoactive agent in the management of circulatory disorders, particularly (CVI), , and , where it helps improve venous tone, reduce inflammation, and enhance microcirculation. It is most commonly administered in the form of micronized purified fraction (MPFF), a formulation comprising 90% micronized diosmin and 10% other (expressed as ), which enhances its and efficacy compared to pure diosmin. Pharmacologically, diosmin acts through multiple mechanisms, including inhibition of leukocyte adhesion to venous walls, antioxidant activity to combat , and modulation of synthesis to alleviate and swelling in venous conditions. Clinical studies have demonstrated its ability to significantly reduce symptoms of CVI, such as leg , , and heaviness, with treatment durations typically ranging from 2 to 6 months showing up to 50% improvement in symptom intensity. In , diosmin-based products like are approved as prescription medications for venous and lymphatic disorders, while in the United States, it is regulated as a without FDA approval for specific therapeutic claims, though it has received designation for investigating its use in systemic sclerosis. Emerging research highlights its broader therapeutic potential, including anti-diabetic effects by improving insulin sensitivity, neuroprotective benefits, and anti-cancer properties through induction, underscoring its role as a versatile in functional foods and nutraceuticals.

Chemical Properties

Molecular Structure

Diosmin is a flavone glycoside characterized by the molecular formula \ce{C28H32O15} and a molecular weight of 608.5 g/mol. Its systematic name is diosmetin 7-O-rutinoside, corresponding to 3′,5,7-trihydroxy-4′-methoxyflavone-7-rutinoside. The core structure consists of a flavone backbone, featuring two aromatic rings (A and B) fused to a central γ-pyrone ring, with the aglycone being diosmetin—a flavone substituted with hydroxyl groups at positions 5, 7, and 3′ on the A and B rings, respectively, and a methoxy group at the 4′ position on the B ring. At the 7-position on the A , diosmin bears a rutinoside moiety, a composed of a β-D-glucopyranosyl unit linked at its 6-position to an α-L-rhamnopyranosyl group via a . This rutinoside attachment via the glycosidic linkage imparts greater hydrophilicity to the molecule compared to its aglycone, thereby influencing its solubility properties. Diosmin is derived from , a structurally similar found in fruits, serving as a key precursor in its chemical preparation.

Sources and Synthesis

Diosmin occurs naturally in the pericarp and pulp of various fruits, including (Citrus aurantium), sweet orange (), and (Citrus limon), where it serves as a contributing to the plant's defenses. It was first isolated in 1925 from the herb nodosa (common figwort), a plant in the family, though commercial quantities are predominantly sourced from byproducts. Extraction from plant material typically involves solvent-based isolation from fruit peels, using methods such as or extraction followed by precipitation and purification to yield crude diosmin. For pharmaceutical production, diosmin is primarily obtained through semi-synthetic routes, converting —a structurally related abundant in peels—via selective oxidation at the C-2 position. This transformation is commonly achieved through dehydrogenation or iodine-catalyzed oxidation, where iodine acts as an oxidant in the presence of bases like or , yielding diosmin with high selectivity and minimal byproducts. Industrial synthesis has advanced to include microwave-assisted processes, which accelerate the iodine-catalyzed oxidation of using I₂/NaI as catalysts in mixed solvents like with K₂CO₃/NaOH and , achieving yields over 80% in reduced time compared to conventional heating. These methods also facilitate recovery of valuable byproducts, such as diosmetin (the aglycone form of diosmin), through of the glycosidic bonds post-reaction. Emerging approaches as of 2024 include biosynthetic production using in plants such as , reconstituting the pathway to yield diosmin without chemical oxidation. For pharmaceutical applications, purified diosmin must comply with standards like those in the (EP 7.0 or later editions), requiring at least 90% purity by HPLC and limits on impurities such as (≤5%).

Pharmacology

Mechanism of Action

Diosmin, a , primarily exerts its pharmacological effects through its conversion to the aglycone metabolite diosmetin in the body, which contributes to its vascular protective actions. Diosmin demonstrates venoactive properties by prolonging norepinephrine-induced , thereby enhancing venous tone and reducing venous distensibility. This mechanism involves inhibition of noradrenaline in venous tissues, leading to increased of vascular to adrenergic stimulation. It also reduces permeability by stabilizing endothelial junctions and inhibiting hyperpermeability in the , which helps prevent fluid and . This effect is mediated through modulation of vascular integrity and reduction in inflammatory mediators that compromise . The actions of diosmin include suppression of leukocyte , adhesion to endothelial cells, and into tissues, as well as inhibition of synthesis. These processes are achieved by downregulating pro-inflammatory cytokines and molecules, thereby mitigating vascular and associated damage. Diosmin exhibits antioxidant effects by scavenging free radicals and inhibiting enzymes involved in oxidative stress, such as xanthine oxidase, which reduces the production of reactive oxygen species and protects vascular from oxidative injury. Furthermore, diosmin enhances lymphatic drainage by increasing lymphatic flow and frequency of contractions while reducing formation through improved lymphatic vessel contractility and decreased capillary filtration. Although not fully established, diosmin may interact with the (AhR), potentially influencing related to vascular protection and , as demonstrated by its agonistic activity on this receptor.

Pharmacokinetics

Diosmin exhibits low oral primarily due to its poor , necessitating in the to its aglycone form, diosmetin, by enzymes from intestinal before can occur. This enhances its and enables uptake, with diosmetin being absorbed mainly in the . Following , peak plasma concentrations of diosmetin are typically reached within 1-2 hours post-dose, reflecting rapid initial . Once absorbed, diosmetin undergoes in the liver, where it is primarily esterified to and sulfate conjugates. These metabolites are then distributed throughout the body, with notable accumulation in venous tissues and endothelial cells of veins and lymphatic vessels, contributing to its localized effects. The elimination of these metabolites ranges from approximately 26 to 43 hours, allowing for sustained presence in circulation. Excretion occurs primarily via for unabsorbed portions, with metabolites and conjugates eliminated in the (minor fraction), and to a lesser extent via . Complete elimination is achieved within 5-7 days, as evidenced by studies tracking radiolabeled diosmin, where nearly 100% of the administered dose is recovered in and over this period.

Clinical Uses

Venous and Lymphatic Disorders

Diosmin, primarily administered as micronized purified flavonoid fraction (MPFF), is widely used in the management of (CVI), where it reduces symptoms such as leg pain, swelling, and heaviness. A and of seven randomized double-blind placebo-controlled trials involving 1,692 patients demonstrated significant improvements in these symptoms, with relative risks (RR) ranging from 0.35 for heaviness to 0.53 for pain, alongside enhanced (standardized mean difference [SMD] -0.21, 95% -0.37 to -0.04). Moderate-certainty evidence from a Cochrane of 54 randomized controlled trials (RCTs) further supports phlebotonics like diosmin in slightly reducing (RR 0.70, 95% 0.63-0.78) and ankle circumference in CVI patients. These benefits are particularly notable in early CEAP classification stages (C2-C3), where diosmin improves patient-reported outcomes without altering disease progression fundamentally. In treatment, diosmin provides short-term relief from acute symptoms including and , and aids in preventing postoperative complications. A of four RCTs showed MPFF significantly reduced (odds ratio [OR] 0.082, 95% CI 0.027-0.250) and discharge (OR 0.12, 95% CI 0.04-0.42), with overall symptom improvement rated highly by both patients (OR 5.25, 95% CI 2.58-10.68) and investigators (OR 5.51, 95% CI 2.76-11.0). The Cochrane review of 20 RCTs (2,344 participants) corroborated these findings, reporting reduced (OR 0.12, 95% CI 0.04-0.37) and pruritus (OR 0.23, 95% CI 0.07-0.79) compared to or no treatment, especially in acute episodes and post-hemorrhoidectomy settings. durations for typically span 4-7 days at higher doses (1,000-2,000 mg/day), followed by . As an adjunct therapy for and leg s, diosmin promotes healing and reduces by supporting venous tone. In venous leg ulcers (CEAP class ), a of five European studies (723 patients) found micronized diosmin effective for middle-sized ulcers (5-10 cm²), accelerating healing in those persisting 6-12 months when combined with compression therapy. An RCT demonstrated that 60 days of 500 mg (two tablets daily) plus elastic compression significantly sped ulcer healing compared to compression alone, with benefits attributed to decreased . These effects extend to varicose vein-related symptoms, where diosmin mitigates swelling and discomfort as part of multimodal care. For , diosmin enhances lymphatic , particularly in post-surgical or chronic cases. In a randomized double-blind placebo-controlled trial of 94 women with secondary after treatment, 500 mg (two tablets/day for 6 months) improved lymphatic parameters in severe cases, including migration speed (Δ 0.84 cm/min, p=0.005) and of colloidal clearance (Δ 10.3 min, p=0.034), though overall arm volume reduction was not significant. This supports its role in adjunctive to alleviate swelling and improve post-surgery. Meta-analyses confirm diosmin's efficacy across CEAP stages, with high-quality evidence from RCTs and real-world studies showing sustained symptom relief over 4-6 months of treatment at 1,000 mg/day. For instance, prolonged courses (up to 6 months) yield optimal outcomes in CVI and ulcers, while shorter regimens suffice for acute hemorrhoidal flares. These findings underscore diosmin's established role in guideline-recommended therapy for venous and lymphatic disorders, focusing on symptom control and quality of life enhancement.

Emerging and Investigational Applications

Diosmin has shown preliminary promise in preclinical models of , where it improves insulin sensitivity and mitigates . In streptozotocin-nicotinamide-induced diabetic rats, oral administration of diosmin at 100 mg/kg/day for 45 days significantly reduced plasma glucose levels, elevated insulin concentrations, and restored antioxidant enzyme activities such as , , , and glutathione-S-transferase in the liver and , while decreasing . Similarly, in high-fat diet-induced obese mice, local delivery of diosmin to inguinal enhanced insulin sensitivity, lowered fasting blood glucose, and reduced hepatic by modulating PPARγ activity without promoting . These effects highlight diosmin's potential to address and , key pathological features of , while large-scale human trials are still needed, preliminary evidence from a 2022 RCT suggests benefits in improving metabolic profiles and reducing in patients with . In the realm of , diosmin exhibits anticancer properties primarily through inhibition of tumor and induction of , as demonstrated in and rodent studies. In cell lines such as and MDA-MB-231, diosmin (: 13.93–19.46 μM) triggers G2/M arrest, upregulates and p21, and promotes and via increased and DNA damage. For colon cancer, diosmin suppresses proliferation in HCT-116 cells by inactivating , releasing , and activating , often involving downregulation of the PI3K/Akt/ pathway to enhance , particularly when combined with inhibitors like dactolisib. Rodent models further support these findings, with diosmin reducing tumor growth in xenografts in mice and increasing CD4+/+ T-cell infiltration, indicating immunomodulatory effects. Diosmin's neuroprotective potential has been explored in models of , where it reduces neuroinflammation and associated pathologies. In 3xTg-AD mice, oral diosmin at low (50 mg/kg) and high (500 mg/kg) doses decreased cerebral soluble Aβ1–40/42 levels by 37–51%, lowered Aβ accumulation by 26–31% (especially in females), and inhibited hyperphosphorylation at Thr231 (55–86% reduction) and Ser202 (42–75% reduction) through glycogen synthase kinase-3β suppression. It also curbed pro-inflammatory microglial activation by reducing IFNγ-induced CD40 expression and TNFα/IL-12 production , while enhancing Aβ phagocytosis. Preliminary suggests similar benefits in ischemia/ models, protecting against cerebral damage, though stroke-specific rodent data is limited. Beyond diabetes and neurodegeneration, diosmin may offer cardiovascular benefits in hypertension by eliminating superoxide anions. In deoxycorticosterone acetate-salt-induced hypertensive rats, diosmin normalized blood pressure, restored antioxidant defenses (SOD, CAT, GSH), and reduced lipid peroxidation in plasma and tissues like the aorta and heart, with superoxide scavenging identified as a core mechanism. This antioxidant action was corroborated in L-NAME-induced models, where diosmin mitigated oxidative stress in vascular tissues. Emerging applications also include and activity, particularly when formulated with nanoparticles. In excision models, diosmin-loaded nanoemulsion gels (globule size 41 nm, entrapment efficiency 87%) accelerated contraction from day 7 to 21, improved deposition, and reduced (50.69% inhibition) compared to controls. Diosmin nanocrystals in alginate wafers enhanced healing of diabetic ulcers in s via topical application. Additionally, diosmin demonstrates effects against like and , with potential synergy in nanoparticle complexes for infection control. However, the majority of evidence for these investigational uses derives from preclinical and animal studies, with no robust to confirm efficacy or safety in humans, necessitating further .

Safety Profile

Adverse Effects

Diosmin is generally well-tolerated, with the most common adverse effects being mild and primarily gastrointestinal in nature, affecting approximately 10% of users compared to 13.9% in groups. These include stomach pain, , , dyspepsia, , , and skin manifestations such as , , or itching. Such effects are comparable in incidence and severity to those observed with in randomized controlled trials, and they typically resolve upon discontinuation of the medication without long-term sequelae. Discontinuation rates due to adverse events are low, at about 1.1% for diosmin versus 3.2% for . No evidence of severe organ toxicity, such as hepatic or renal impairment, has been reported in clinical studies, with stable laboratory parameters including blood glucose and hepatic enzymes observed even after prolonged use. Rarer adverse effects include , leg cramps (manifesting as myalgias), and allergic reactions in sensitive individuals, with an overall incidence of adverse events around 11-12% in systematic reviews of trials for chronic venous disorders. These uncommon events, such as or elevated phosphokinase, are generally transient and do not necessitate beyond symptom . In terms of long-term safety, diosmin has demonstrated good tolerability in studies lasting up to 2 years for , with minimal adverse effects like occasional gastric dyspepsia reported even over 5 years of continuous use in some cohorts, and no increase in incidence over time.

Contraindications and Drug Interactions

Diosmin is contraindicated in individuals with to or any of its components, as this may lead to allergic reactions. Not recommended for use in children due to insufficient safety data. Additionally, patients with rare hereditary disorders such as galactose intolerance, Lapp lactase deficiency, or glucose- should avoid diosmin formulations containing excipients, which could exacerbate these conditions. Use of diosmin requires caution during and due to limited data on its safety in these populations; while it is commonly consumed from fruits, supplemental use has not been fully established as safe, and precautionary avoidance is recommended, though short-term use with may be acceptable based on some studies. Diosmin may interact with medications that are substrates of (P-gp) efflux pumps, potentially increasing their bioavailability and serum levels; examples include and cyclosporine, where co-administration could lead to elevated drug exposure and necessitate monitoring. It also exhibits potential additive effects with anticoagulants or antiplatelet drugs, as diosmin may slow blood clotting, increasing the risk of bruising or bleeding when combined. The primary metabolite diosmetin contributes to these P-gp inhibitory effects. In special populations with renal or hepatic impairment, dose reduction may be warranted to minimize potential accumulation, although diosmin generally demonstrates a favorable safety profile without major adjustments in most cases. shows no major interactions with enzymes, though minor inhibitory effects on isoforms like and have been observed , suggesting limited clinical relevance for most substrates. Patients on multiple medications (polypharmacy) should consult a before initiating diosmin to assess for potential interactions and ensure safe use.

History and Development

Discovery and Isolation

Diosmin was first isolated in 1925 from the plant Scrophularia nodosa (figwort), a species native to the belonging to the family. The isolation was reported by chemists O. A. Österle and G. Wander in their study published in Helvetica Chimica Acta, marking the initial identification of the compound from plant extracts. This discovery occurred amid early 20th-century efforts to explore bioactive compounds in . In , diosmin underwent further characterization as part of broader investigations into plant phenolics and . It was recognized as a , consisting of the aglycone diosmetin bound to a rutinose moiety, through chemical analyses that aligned it with other naturally occurring structures. Hungarian chemist Géza Zemplén and collaborator R. Bognár contributed significantly to its structural elucidation in 1943, confirming its configuration via and methods in their work published in Berichte der Deutschen Chemischen Gesellschaft. Initial observations of bioactivity for flavonoids, including potential vascular effects, emerged in the 1940s through animal experiments focused on vascular function. Studies noted their potential to strengthen capillaries and reduce permeability, building on contemporaneous research into flavonoids' roles in permeability regulation. By the 1950s, pre-therapeutic research linked diosmin to citrus bioflavonoids in nutritional studies, highlighting its presence in citrus fruits and its synergy with vitamin C in supporting vascular health and antioxidant activity. These findings positioned diosmin within the class of bioflavonoids once considered for classification as "Vitamin P" due to their effects on capillary integrity.

Pharmaceutical Development

Diosmin was first introduced as a therapeutic agent in 1969 in , where it gained recognition as a phlebotonic and vascular-protecting compound primarily for treating , , , and . This marked its transition from a research compound to a clinically viable option, with initial applications focusing on improving venous tone and reducing symptoms associated with circulatory disorders. A significant advancement came with the development of the micronized purified flavonoid fraction (MPFF), a combining 90% micronized diosmin with 10% , exemplified by the product . This semi-synthetic preparation, derived from extracted from fruits, enhanced and therapeutic efficacy compared to pure diosmin, enabling better absorption and targeted action on vascular tissues. MPFF was designed to address limitations in earlier diosmin formulations, promoting its widespread adoption in phlebotonic therapy. During the and , randomized controlled trials (RCTs) solidified diosmin's role in venous disease management, with multicenter studies involving thousands of patients demonstrating its ability to alleviate symptoms such as leg , swelling, and heaviness. For instance, a large-scale trial with 5,052 participants using 450 mg diosmin combined with 50 mg daily reported significant improvements in and venous function over several months. These RCTs, conducted primarily in , established efficacy benchmarks for diosmin-based therapies in chronic venous disorders. Production of diosmin involved scaling semi-synthetic processes to manufacture it from , improving purity and yield for commercial applications. In the early , diosmin achieved status as a in the United States following New Dietary Ingredient notifications, allowing over-the-counter availability without approval. In the , advanced toward combination therapies and novel indications, with studies exploring diosmin's potential in cancer, , and inflammatory conditions like , often in synergy with to broaden its pharmacological scope.

Regulatory Aspects

Approval Status

In , diosmin has been approved as a medicinal product since the 1970s for the treatment of (CVI) and associated symptoms, such as venous leg ulcers and . It is recognized through the (EMA) via national marketing authorizations for formulations like , a micronized purified flavonoid fraction containing 90% diosmin, which is indicated for venolymphatic insufficiency. Availability varies by country: it requires a prescription in , while it is often sold over-the-counter in nations including , , and . In the United States, diosmin is not approved by the Food and Drug Administration (FDA) as a prescription drug but has been marketed as a dietary supplement since the enactment of the Dietary Supplement Health and Education Act in 1994. Products containing diosmin, such as DiosVein, are available over-the-counter for supporting vascular health, and certain diosmin-derived ingredients have received Generally Recognized as Safe (GRAS) status for use in foods. Diosmin is approved for venous disorders in various other regions, including , , and , with availability ranging from prescription-only to over-the-counter based on local regulations. In , the Central Drugs Standard Control Organization (CDSCO) has authorized diosmin-hesperidin combinations for CVI and . Brazil's National Health Surveillance Agency (ANVISA) approves similar formulations for vascular conditions, and in , it is registered for chronic venous disease management. Diosmin is recognized in guidelines for the of venous diseases, including recommendations for venoactive agents in managing CVI symptoms. As of November 2025, no significant regulatory changes have occurred globally, though evaluations continue for potential broader therapeutic applications.

Dosage Forms and Administration

Diosmin is primarily available in oral tablet formulations, often as a micronized purified flavonoid fraction (MPFF) containing 450 mg diosmin combined with 50 mg , such as in products like Daflon 500. Other forms include capsules, powders, and granules for oral use, with strengths typically ranging from 100 mg to 900 mg per dose. These formulations are designed for improved , as enhances gastrointestinal absorption of the poorly water-soluble compound. For chronic venous insufficiency (CVI), the standard dosing regimen is 450 to 900 mg of diosmin daily, administered in divided doses (e.g., 500 mg twice daily) for 2 to 6 months. In acute hemorrhoidal attacks, higher short-term doses of 2 to 3 g daily (as MPFF) are used, such as 3,000 mg MPFF (containing approximately 2,700 mg diosmin; e.g., six 500 mg tablets) three times daily? No, wait: standard is 3,000 mg MPFF daily (six tablets) for the first 4 days, followed by 2,000 mg MPFF (four tablets) daily for 3 days. Administration should occur with meals to optimize absorption, as food enhances the hydrolysis of diosmin to its active aglycone form, diosmetin. For chronic management of hemorrhoids, 1,000 mg daily (as MPFF, approximately 900 mg diosmin) may be continued for up to 3 months. Diosmin is frequently combined with compression therapy, such as graduated stockings, to improve outcomes in CVI by addressing both pharmacological and mechanical aspects of venous support. No dose adjustment is necessary for elderly patients or those with impaired renal function. Diosmin is contraindicated in children due to insufficient safety data. In cases of overdose, diosmin exhibits low toxicity, with management limited to supportive care such as monitoring and gastrointestinal if ingestion is recent, as no specific exists.