Diosmetin (Flavone · Vascular Protective · Anti-inflammatory)

Compound	Diosmetin (Diosmin aglycone; 5,7,3′-Trihydroxy-4′-methoxyflavone)
Chemical class	Polyphenol — Flavone (luteolin 4′-methyl ether; diosmin deglycosylated form)
CAS	520-34-3
Primary source	Citrus limon (lemon peel), Vicia faba (broad bean), Lamiaceae herbs including Origanum
Key applications	Vascular protective (CVI); anti-inflammatory; antioxidant; lymphatic tone
Claim strength	High (via diosmin; Moderate isolated diosmetin)
Typical form	Citrus lemon extract (diosmetin as minor aglycone); diosmin 10% extract (diosmin is the 7-rutinoside of diosmetin)
Buy from Herbuno	Citrus limon (Lemon) Extract Powder → Diosmin 10% (From Citrus) powder →

Name origin: Diosmetin takes its name from diosmin — the flavonoid glycoside of which diosmetin is the aglycone, produced by acid or enzymatic hydrolysis of the 7-O-rutinoside bond. The name diosmin itself derives from Diosma, a South African Rutaceae genus, though commercial diosmin is sourced from Citrus. Traditional use: Citrus peel preparations have been used in Mediterranean folk medicine for circulatory complaints, haemorrhoids, and leg heaviness — conditions now understood as manifestations of chronic venous insufficiency (CVI). Lemon and orange peels were also used as digestive bitters and in Unani medicine for their cooling, anti-inflammatory properties. The flavonoid fraction — including diosmin, hesperidin, and their aglycones including diosmetin — is responsible for the vascular activity. Research trajectory: Diosmin is one of the most clinically studied flavonoids globally, with multiple high-quality RCTs for chronic venous insufficiency (Daflon 500/1000 — a purified flavonoid fraction containing 90% diosmin and 10% hesperidin). Diosmetin as the pharmacologically active aglycone is increasingly studied in isolation; it is generated from diosmin by gut microbial deglycosylation and is the likely final bioactive form. Commercial source: Diosmetin is available from Herbuno via Citrus limon Extract Powder and Diosmin 10% (From Citrus) powder, both delivering the Citrus flavonoid spectrum including diosmin and its aglycone diosmetin.

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Evidence for Diosmetin Applications

Vascular protective / chronic venous insufficiency: Diosmin (diosmetin-7-rutinoside) has High-level evidence from multiple RCTs demonstrating reduction in leg oedema, pain, heaviness, and cramps in CVI, as well as accelerated venous ulcer healing and haemorrhoid symptom reduction. Diosmetin itself — the active metabolite — shows equivalent venous tone improvement and capillary permeability reduction in animal models, supporting its role as the mechanistic driver of diosmin's efficacy. EMA has a well-established use monograph for diosmin. Claim strength: High (diosmin); Moderate (isolated diosmetin).

Anti-inflammatory: Diosmetin inhibits COX-2 and 5-LOX with IC₅₀ values in the low micromolar range, superior to diosmin due to improved membrane penetration without the glycoside. NF-κB and MAPK pathway suppression reduce pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) in macrophage activation models. Claim strength: Moderate.

Antioxidant and neuroprotective: Diosmetin's catechol B-ring (3′-OH, 4′-OMe pattern) confers good radical scavenging activity and metal chelation. Neuroprotective activity via Nrf2/HO-1 induction and neuroinflammation reduction has been characterised in Alzheimer's and Parkinson's disease cell models. Claim strength: Moderate.

Antiproliferative: Diosmetin has demonstrated selective antiproliferative activity in multiple cancer cell lines (breast, lung, colorectal) at 10–50 μM via cell cycle arrest (G2/M) and caspase-dependent apoptosis. Research is preclinical. Claim strength: Emerging.

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Dosage & Formulator Specification

Diosmin (the primary commercial form of diosmetin's glycoside) is used at 500–1000 mg/day in CVI — the Daflon 500 formulation (micronised purified flavonoid fraction: 90% diosmin, 10% hesperidin) having the strongest RCT evidence base. Isolated diosmetin human dosing data are not yet established, but diosmetin's superior bioavailability versus diosmin (no glycoside barrier) suggests effective doses may be lower.

For formulator specification: Citrus lemon extract standardised to ≥10% total flavonoids delivers diosmin and diosmetin alongside hesperidin and eriocitrin. For diosmetin-focused applications, isolated diosmetin ≥98% (HPLC) is available from specialty suppliers. Diosmin 10% extract from Herbuno delivers diosmin as the primary flavonoid with diosmetin as the metabolic precursor.

Diosmetin's lipophilicity (logP ~2.8) is higher than diosmin (logP ~0.3), making it more suitable for lipid-based delivery (softgel, phospholipid complex) where maximum bioavailability is targeted. Micronisation or cyclodextrin complexation improves dissolution for solid dosage forms. Compatible with hesperidin, rutin, and horse chestnut extract in vascular health formulas.

No clinically significant drug interactions are documented for diosmetin. Diosmin preparations should be used with caution in pregnancy (limited safety data); avoid high-dose diosmin/diosmetin in first trimester based on precautionary principle.

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Frequently Asked Questions — Diosmetin

What is the relationship between diosmetin and diosmin?
Diosmin is diosmetin-7-O-rutinoside — diosmetin with a rutinose (glucose + rhamnose) disaccharide attached at C-7. Gut microbial rhamnosidases and glucosidases cleave this sugar to release diosmetin, which is then absorbed from the colon. Diosmetin is therefore both a dietary flavone in Citrus and the gut-derived active metabolite of diosmin — making diosmetin the likely final bioactive form mediating diosmin's vascular effects.

Is diosmetin more bioavailable than diosmin?
Yes — as the aglycone, diosmetin does not require gut microbial deglycosylation before absorption. It can be absorbed in the small intestine by passive transcellular diffusion in addition to colonic uptake, resulting in earlier and potentially higher Cmax than diosmin. Micronised diosmin preparations improve diosmin dissolution to partly compensate for its lower inherent bioavailability.

Which Herbuno products deliver diosmetin?
Citrus limon Extract Powder delivers the full lemon peel flavonoid spectrum including diosmin and trace diosmetin. Diosmin 10% (From Citrus) powder is standardised to diosmin content; diosmetin is generated from diosmin metabolically after ingestion. Both are appropriate for CVI-supporting formulations.

How does diosmetin compare to luteolin structurally?
Diosmetin is luteolin's 4′-methyl ether — the 4′-hydroxyl of luteolin is methylated in diosmetin. This single modification increases lipophilicity, reduces catechol B-ring susceptibility to auto-oxidation, and subtly shifts enzyme selectivity. Luteolin and diosmetin share anti-inflammatory and antioxidant mechanisms; diosmetin has the more established vascular/venous tone evidence base via its glycoside diosmin.

Related compounds: Diosmin, Luteolin, Hesperetin, Chrysin

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Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

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