Eriodictyol (Flavanone · Bitter Taste Inhibitor · Anti-inflammatory)

Compound	Eriodictyol
Chemical class	Polyphenol — Flavanone (3′,4′,5,7-Tetrahydroxyflavanone)
CAS	552-58-9
Primary source	Eriodictyon californicum (yerba santa), Citrus spp., Phlomis spp.
Key applications	Antioxidant, anti-inflammatory, taste-masking (bitter inhibitor)
Claim strength	Moderate
Typical form	Citrus extract constituent; yerba santa extract; isolated eriodictyol

Name origin: Directly from the genus Eriodictyon (yerba santa, literally "holy herb" in Spanish), which was the original botanical source for isolation. Traditional use: Yerba santa (Eriodictyon californicum) was used by indigenous Californian peoples and later adopted by early American settlers as a respiratory herb for coughs, asthma, and mucous congestion. Eriodictyol is identified as a key flavanone contributor to these properties. Research trajectory: Eriodictyol has gained commercial traction in the food industry as a natural bitter-taste inhibitor, an unusual functional role among flavanones. It also has a conventional anti-inflammatory and antioxidant evidence base. Commercial source: Available from citrus peel extracts (co-present with hesperidin) and specialist yerba santa extracts; some dedicated eriodictyol isolates are available for food-grade applications.

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Evidence for Eriodictyol Applications

Bitter taste inhibition: Eriodictyol selectively inhibits the bitter taste receptor hTAS2R31 at low concentrations (EC50 ~5 µM), making it effective at masking the bitterness of caffeine, quinine, and certain botanical actives including chlorogenic acids and some alkaloids. This is a commercially validated function used in functional food and nutraceutical formulation. Claim strength: High (mechanism validated in human sensory panels).

Anti-inflammatory activity: Eriodictyol suppresses NF-κB, COX-2, and NLRP3 inflammasome activation across macrophage and respiratory epithelial models. Animal models of COPD, allergic asthma, and lung injury show eriodictyol reduces mucus hypersecretion and airway inflammation. Claim strength: Moderate.

Antioxidant and neuroprotective activity: Eriodictyol activates Nrf2/HO-1 pathway, inducing endogenous antioxidant defences. Neuroprotective effects in oxidative stress and ischemia models are documented; the catechol B-ring (3′,4′-diOH) is key to metal chelation and radical scavenging activity. Claim strength: Moderate.

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Dosage & Formulator Specification

For bitter taste inhibition in food and supplement applications: eriodictyol is effective at 10–50 ppm (0.001–0.005%) in the finished product. This is a functional rather than nutritional dosing context. Patented taste-modulation applications exist; formulators should verify IP status for intended markets.

For anti-inflammatory or antioxidant supplement applications, dose ranges analogous to other citrus flavanones suggest 100–300 mg/day of an eriodictyol-standardised extract. No dedicated human clinical trial establishes a specific dose-response relationship for eriodictyol as a standalone supplement.

Eriodictyol has moderate aqueous solubility (slightly better than naringenin). Citrus extract co-standardised to eriodictyol alongside hesperidin and naringenin is the most commercially accessible format. For food applications, a water-dispersible form is preferred.

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Frequently Asked Questions — Eriodictyol

What makes eriodictyol unique as a formulation ingredient?
Its bitter taste-masking function at very low use levels (<50 ppm) is genuinely differentiated — few botanical actives serve a dual bioactive/organoleptic function. This makes eriodictyol valuable both as an anti-inflammatory botanical and as a palatability-improvement tool for bitter nutraceutical blends.

Are there IP constraints on using eriodictyol for taste masking?
Yes. Senomyx (now Firmenich) holds patents on eriodictyol’s bitter-taste inhibition applications in certain markets. Formulators should conduct freedom-to-operate analysis before using eriodictyol specifically for taste-masking claims or in patented formulation contexts.

How does eriodictyol compare to naringenin structurally and functionally?
Eriodictyol has a catechol B-ring (3′,4′-diOH) compared to naringenin’s 4′-OH, giving it higher antioxidant capacity and metal chelation activity. The catechol group also contributes to the unique bitter receptor binding profile that naringenin does not share.

Can eriodictyol be used in RTD beverages?
Yes, and this is an established application. Eriodictyol at 20–50 ppm masks bitterness from caffeine, green tea catechins, and herbal extracts in beverages. It is heat-stable at beverage processing temperatures and compatible with standard acidic beverage pH ranges (3.0–4.5).

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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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