Isorhamnetin-3-Glucoside (Flavonol Glycoside · Cardiovascular · Antioxidant)

Compound	Isorhamnetin-3-Glucoside (Isorhamnetin 3-O-β-D-glucoside)
Chemical class	Polyphenol — Flavonol O-Glycoside
CAS	5041-82-7
Primary source	Hippophae rhamnoides (sea buckthorn), Allium cepa (onion), Raphanus sativus
Key applications	Cardiovascular support; antioxidant; photoprotection; anti-inflammatory
Claim strength	Moderate
Typical form	Sea Buckthorn Extract Powder; sea buckthorn fruit liquid extract; isorhamnetin glycoside HPLC-quantified
Buy from Herbuno	Sea Buckthorn Extract Powder → Sea Buckthorn Fruit Liquid Extract (Water Soluble) - Hippophae rhamnoides →

Name origin: Isorhamnetin (3′-methyl ether of quercetin) is glucosylated at the C-3 hydroxyl of the C-ring — the standard flavonol glycosylation position. The 3-glucoside is the primary conjugate found in sea buckthorn fruit, alongside isorhamnetin-3-rutinoside (narcissin) and quercetin glycosides. Traditional use: Sea buckthorn (Hippophae rhamnoides), called Seabuckthorn or Sandthorn, has been used in Tibetan and Mongolian medicine (sJi-tshes in Tibetan) for centuries for digestive disorders, skin burns, and cardiovascular weakness. The berries are among the most nutritionally dense wild fruits, consumed as juice, oil, and decoction across Central Asian medicine. Research trajectory: Modern research has focused on sea buckthorn's cardiovascular, hepatoprotective, and skin-protective activities. Isorhamnetin-3-glucoside, as one of the dominant flavonoids in the fruit, has attracted attention for myocardial protection, platelet aggregation modulation, and UVB-induced skin damage mitigation. Commercial source: Sea Buckthorn Extract Powder is available from Herbuno, delivering isorhamnetin glycosides as part of the full sea buckthorn polyphenol complex.

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Evidence for Isorhamnetin-3-Glucoside Applications

Cardiovascular support: Isorhamnetin glycosides inhibit platelet aggregation via thromboxane A₂ pathway suppression and reduce LDL oxidation ex vivo. Rodent myocardial ischaemia-reperfusion studies show cardioprotective effects at 10–50 mg/kg via NF-κB inhibition and antioxidant enzyme upregulation. Sea buckthorn berry preparations have been evaluated in two small RCTs for cardiovascular risk markers. Claim strength: Moderate.

Antioxidant activity: The 3′-methoxy modification reduces the catechol B-ring's susceptibility to auto-oxidation compared to quercetin, potentially extending plasma half-life. ORAC and FRAP values are comparable to quercetin-3-glucoside (isoquercitrin). In vivo antioxidant biomarker improvement has been observed in sea buckthorn consumption trials. Claim strength: Moderate.

Photoprotection: Topical application of isorhamnetin-containing sea buckthorn extracts reduces UVB-induced cyclobutane pyrimidine dimer formation and IL-6 elevation in keratinocyte models. Oral sea buckthorn supplementation modulates skin carotenoid levels via carotenoid co-delivery, adding a second photoprotective mechanism. Claim strength: Emerging.

Anti-inflammatory and metabolic: Isorhamnetin-3-glucoside inhibits 5-LOX and COX-2 at micromolar concentrations. AMPK activation and PPAR-γ modulation have been reported in adipocyte models, suggesting potential metabolic applications in lipid-lowering formulations. Claim strength: Emerging.

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Dosage & Formulator Specification

No isolated isorhamnetin-3-glucoside clinical dosing data are available. Sea buckthorn berry preparations studied for cardiovascular endpoints used 5–30 g/day freeze-dried berry or 300–600 mg/day concentrated extract delivering mixed polyphenols at 5–15% total flavonoids. Isorhamnetin glycosides typically represent 0.5–3% of dry sea buckthorn extract weight.

For isorhamnetin-standardised formulations, sea buckthorn dry extract at ≥1% total isorhamnetin glycosides is a reasonable specification for clinical-intent products. HPLC quantification distinguishing isorhamnetin-3-glucoside from isorhamnetin-3-rutinoside (narcissin) is achievable via standard reversed-phase methods.

Sea buckthorn extract is highly compatible with softgel delivery (the fruit oil fraction provides a natural lipid matrix) and with stick-pack formats for beverage applications. The extract has strong orange colour from carotenoid co-delivery — account for this in colour-sensitive applications.

Sea buckthorn preparations containing vitamin K (in the leaf fraction) may interact with warfarin; fruit-only extracts carry lower risk.

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Frequently Asked Questions — Isorhamnetin-3-Glucoside

What is the relationship between isorhamnetin-3-glucoside and quercetin?
Isorhamnetin is quercetin's 3′-O-methylated metabolite — formed endogenously from quercetin by catechol-O-methyltransferase (COMT) after absorption. Dietary isorhamnetin-3-glucoside from sea buckthorn thus converges with endogenous quercetin metabolism, creating a pharmacological overlap.

How does sea buckthorn extract deliver isorhamnetin-3-glucoside alongside other actives?
Sea buckthorn fruit co-delivers isorhamnetin glycosides with carotenoids (beta-carotene, lycopene, zeaxanthin), vitamin C, vitamin E tocopherols, and omega-7 fatty acids — making the extract inherently multi-functional across skin, cardiovascular, and immune positioning.

Is isorhamnetin-3-glucoside the same compound as narcissin?
No — narcissin is isorhamnetin-3-O-rutinoside (glucose + rhamnose disaccharide), while isorhamnetin-3-glucoside carries only a single glucose at C-3. Both occur in sea buckthorn; narcissin predominates in onion outer scales.

Can isorhamnetin-3-glucoside be used in topical formulations for photoprotection?
Sea buckthorn extracts are used in topical SPF-boosting and after-sun formulations with evidence for UVB damage reduction. Standardised isorhamnetin glycoside content ensures consistent UV-absorbing activity; the carotenoid fraction further supports skin antioxidant claims.

Related compounds: Isorhamnetin, Quercetin, Laricitrin, Syringetin

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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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