Sakuranetin (Flavanone · Phytoalexin · Anti-inflammatory)

Compound	Sakuranetin (4′,5-Dihydroxy-7-methoxyflavanone; Naringenin 7-methyl ether)
Chemical class	Polyphenol — Flavanone (naringenin with C-7 O-methylation; rice phytoalexin)
CAS	1486-69-7
Primary source	Oryza sativa (rice leaves — stress-induced phytoalexin), Prunus serrulata (cherry blossom/Sakura), Baccharis spp.
Key applications	Anti-inflammatory; antifungal; phytoalexin research; antiallergic
Claim strength	Moderate
Typical form	Not commercially standardised as an extract; research-grade isolate; minor constituent of rice stress preparations
Buy from Herbuno	Availability on request — request bulk pricing →

Name origin: Sakuranetin is named after Prunus serrulata (Sakura — Japanese cherry blossom), from which it was first isolated as a bark constituent. "Sakura" (桜) means cherry blossom in Japanese. However, sakuranetin is more broadly significant as a phytoalexin — a stress-induced antimicrobial compound — in Oryza sativa (rice), where it is biosynthesised from naringenin by CYP76M enzymes in response to fungal infection, UV irradiation, or mechanical wounding. Traditional use: Sakuranetin does not have independent traditional medicinal use as a compound. Cherry bark preparations (wild cherry, Prunus species) have traditional use for cough and respiratory conditions in Western herbal medicine — activities attributed primarily to prunasin (a cyanogenic glycoside) and tannins rather than sakuranetin specifically. Rice (as a food and in Ayurvedic preparations like rice water, laja — parched rice) has broad traditional nutritional use with no specific sakuranetin-attributed activity. Research trajectory: Sakuranetin has attracted research interest as a natural anti-inflammatory with structural simplicity (naringenin 7-methyl ether), anti-allergic activity in asthma models, and antifungal activity (consistent with its phytoalexin role against fungal pathogens in rice). Its methoxylation at C-7 increases lipophilicity over naringenin, improving membrane penetration for both intracellular anti-inflammatory and antifungal membrane disruption activities. Commercial source: Sakuranetin is not available as a standardised commercial extract; availability on request for specialty applications.

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Evidence for Sakuranetin Applications

Anti-inflammatory activity: Sakuranetin inhibits NF-κB, COX-2, and 5-LOX in macrophage models at 10–50 μM, with potency generally superior to naringenin due to its 7-methyl ether's enhanced membrane penetration. In LPS-stimulated models, sakuranetin reduces TNF-α, IL-1β, and IL-6 production dose-dependently. Carrageenan paw oedema animal data confirm in vivo anti-inflammatory activity. Claim strength: Moderate.

Anti-allergic and anti-asthmatic: Sakuranetin has demonstrated significant mast cell stabilisation activity — inhibiting IgE-mediated degranulation and histamine release in RBL-2H3 mast cell models. In ovalbumin-sensitised asthma mouse models, sakuranetin reduces airway eosinophilia, mucus hypersecretion, and IL-4/IL-5/IL-13 production (Th2 cytokines) — a mechanistically relevant finding for allergic airway disease. Claim strength: Moderate (preclinical).

Antifungal activity: As a phytoalexin evolved against fungal pathogens of rice, sakuranetin demonstrates antifungal activity against Magnaporthe oryzae (rice blast fungus), Candida albicans, and dermatophytes in MIC assays. The C-7 methoxy group enhances membrane disruption capacity versus naringenin. Claim strength: Moderate (phytoalexin context); Emerging (human pathogens).

Hepatoprotective: In CCl₄-induced liver injury models, sakuranetin at 25–100 mg/kg reduces ALT, AST, and MDA elevation while upregulating antioxidant enzymes (SOD, CAT, GPx). Nrf2/HO-1 pathway activation is the proposed mechanism. Claim strength: Emerging.

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Dosage & Formulator Specification

No human supplement dosing data exist for sakuranetin. Animal model anti-inflammatory effective doses of 25–100 mg/kg translate to estimated human equivalent doses of 250–1000 mg/day — achievable only with concentrated isolate preparations. Sakuranetin is not currently available as a commercial botanical extract; research-grade isolate from specialty suppliers is the primary access route.

For formulators interested in the naringenin methyl ether activity profile, sakuranetin's anti-inflammatory and anti-allergic activity is mechanistically related to that of other flavanone methyl ethers (bavachin, sterubin, eriodictyol methyl ether). No commercially standardised plant extract currently delivers meaningful sakuranetin concentrations — black rice extract contains negligible sakuranetin as it is a stress-response phytoalexin produced only under infection or UV challenge.

Sakuranetin's stability is better than naringenin in aqueous formulations due to the 7-methyl ether reducing glucuronidation susceptibility. Lipid-based delivery (softgel, emulsion) is appropriate given logP ~2.8. No compatibility issues are documented with common supplement co-formulants.

No drug interactions are documented for sakuranetin. The CYP3A4 inhibition profile shared with naringenin (as the 7-methyl ether) may be lower than naringenin at equivalent concentrations due to reduced receptor complementarity.

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Frequently Asked Questions — Sakuranetin

What is a phytoalexin and how does sakuranetin function as one in rice?
Phytoalexins are antimicrobial secondary metabolites produced de novo by plants in response to biotic stress (fungal/bacterial infection) or abiotic stress (UV, wounding). In Oryza sativa, sakuranetin biosynthesis is rapidly induced within hours of fungal attack (particularly Magnaporthe oryzae — rice blast) via CYP76M-mediated methylation of naringenin at C-7. Sakuranetin accumulates in infected leaf tissue at concentrations inhibiting fungal growth — a molecular immune response. This phytoalexin function explains why sakuranetin is not abundant in normal rice grain or leaf and why it cannot be sourced from stable rice extract preparations.

How does sakuranetin's structure compare to naringenin and bavachin?
All three are flavanones based on the naringenin scaffold. Naringenin: 4′,5,7-trihydroxyflavanone. Sakuranetin: naringenin 7-methyl ether (4′,5-dihydroxy, 7-methoxyflavanone). Bavachin: naringenin 6-prenylflavanone (4′,7-dihydroxy, 6-prenyl). The C-7 methylation of sakuranetin increases lipophilicity and metabolic stability versus naringenin; the C-6 prenylation of bavachin increases membrane penetration via hydrophobic interaction. Both modifications enhance biological activity relative to naringenin in anti-inflammatory assays.

Is Prunus serrulata (cherry blossom) a practical source of sakuranetin?
Cherry blossom bark and leaves contain sakuranetin alongside other polyphenols (prunasin, hydroxycinnamic acids, flavonoids), but not at commercially extractable concentrations for standardised supplement use. Cherry preparations in herbal medicine are primarily valued for their antitussive activity (via prunasin) and tannin astringency rather than sakuranetin. Baccharis trimera, a South American medicinal plant, is a richer source used in Brazilian folk medicine where sakuranetin is a characterised constituent.

What are the anti-allergic applications of sakuranetin?
Sakuranetin's mast cell stabilisation activity — inhibiting IgE-mediated histamine release — is relevant to allergic rhinitis, urticaria, and atopic conditions in formulation strategy. The ovalbumin asthma model data showing reduced Th2 cytokines and airway eosinophilia suggest potential utility in atopic asthma formulas. However, human clinical validation is completely absent; sakuranetin occupies the research-stage position for anti-allergic supplement development.

Related compounds: Naringenin, Bavachin, Eriodictyol, Sterubin

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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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