p-Coumaric Acid (Hydroxycinnamic Acid · Antioxidant · Antimicrobial)

Compound	p-Coumaric Acid
Chemical class	Polyphenol — Hydroxycinnamic Acid (4-Hydroxycinnamic Acid)
CAS	7400-08-0
Primary source	Ubiquitous — grains, legumes, Cinnamomum spp., most plant foods
Key applications	Antioxidant, anti-inflammatory, antimicrobial
Claim strength	Moderate
Typical form	Ubiquitous dietary phenolic; cinnamon extract co-constituent; propolis
Buy from Herbuno	Cinnamon Extract Powder - Cinnamomum verum → Cinnamon Polyphenols 20% Powder (Cinnamon Extract) | Standardized Cinnamomum cassia →

Name origin: From Coumarou — the Caribbean name for the tonka bean tree (Dipteryx odorata), an early source for the related compound coumarin. The “p” prefix denotes the para-position of the hydroxyl group on the phenyl ring. Traditional use: p-Coumaric acid is one of the most abundant hydroxycinnamic acids in the human diet — present in virtually all plant foods including tomatoes, carrots, garlic, and cereal grains. As a ubiquitous dietary constituent, it does not have targeted traditional use but contributes to the broad health properties attributed to plant-rich diets. Research trajectory: p-Coumaric acid has well-characterised antioxidant, anti-inflammatory, antimicrobial, and gastroprotective mechanisms in preclinical research. Clinical evidence is limited for the isolated compound; most human data derive from dietary patterns rich in hydroxycinnamic acids collectively. Commercial source: Present as a constituent of cinnamon extract and propolis; isolated p-coumaric acid is available from specialist chemical suppliers. Contact Herbuno for sourcing availability.

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Evidence for p-Coumaric Acid Applications

Antioxidant capacity: p-Coumaric acid has a single para-hydroxyl group giving moderate radical-scavenging capacity — lower than caffeic acid (catechol) but meaningful as a dietary antioxidant. DPPH IC50 values are in the low millimolar range. Contributes to overall dietary antioxidant intake from diverse plant sources. Claim strength: Moderate.

Anti-inflammatory and gastroprotective: p-Coumaric acid inhibits NF-κB and reduces gastric ulcer formation in animal models (indomethacin-induced ulcer), providing gastroprotective effects comparable to omeprazole in some assays. COX inhibition at higher concentrations is documented. Relevant for GI health formulations. Claim strength: Moderate.

Antimicrobial activity: p-Coumaric acid demonstrates inhibitory activity against a range of food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes, and Salmonella at MIC values in the low millimolar range. Relevant for natural preservation and oral health applications. Claim strength: Moderate.

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Dosage & Formulator Specification

No established human supplement dose for isolated p-coumaric acid. Dietary exposure from typical plant-rich diets: 10–50 mg/day from diverse food sources. For supplement delivery, p-coumaric acid is most practically provided as a constituent of broader polyphenol matrices (cinnamon extract, propolis, mixed plant extract blends) rather than as an isolated active.

Cinnamon extract (Herbuno: Cinnamon Extract Powder and Cinnamon Polyphenols 20%) contains p-coumaric acid alongside cinnamaldehyde, cinnamic acid, procyanidins, and other polyphenols. For applications specifically targeting p-coumaric acid activity, isolated material from specialist suppliers is required; request HPLC-verified purity (≥98%).

p-Coumaric acid has good aqueous solubility (better than more hydrophobic hydroxycinnamic acids). Stable at acidic to neutral pH. Suitable for tablet, capsule, and aqueous liquid formulations. Antimicrobial activity in RTD beverage formats may provide dual benefit of preservation and bioactivity.

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Frequently Asked Questions — p-Coumaric Acid

How does p-coumaric acid differ from caffeic acid?
p-Coumaric acid has one B-ring hydroxyl (para position); caffeic acid has two (catechol pattern). The catechol B-ring in caffeic acid provides substantially higher antioxidant capacity and more potent NF-κB inhibition. p-Coumaric acid has a simpler structure and lower potency than caffeic acid in most biological assays but is more widely distributed and more abundant in the diet. Both are metabolic precursors to more complex hydroxycinnamic acid esters.

Is p-coumaric acid a precursor to other bioactive compounds?
Yes. p-Coumaric acid is a central biosynthetic intermediate in plant phenylpropanoid metabolism, serving as the precursor to caffeic acid (via hydroxylation), ferulic acid (via methylation), and lignin monomers. In human metabolism, p-coumaric acid is a dietary source for the formation of 4-hydroxyphenylpropionic acid and related gut microbial metabolites that contribute to antioxidant activity. It is also a precursor to tyrosine in some metabolic contexts.

Can p-coumaric acid be used as a natural food preservative?
Yes — its antimicrobial activity against food-borne pathogens supports natural food preservation applications. It is generally recognised as safe in food contexts across most regulatory frameworks and can be declared as a natural plant extract constituent. Synergy with other natural antimicrobials (thymol, carvacrol, essential oil components) is documented and relevant for clean-label preservation strategies.

Does p-coumaric acid have UV-absorbing properties?
Yes. p-Coumaric acid absorbs UV radiation at approximately 308 nm with moderate molar extinction coefficient — less potent UV absorption than sinapic acid (326 nm) or ferulic acid (320 nm) but still relevant as a minor contributor to topical photoprotection formulations. Its absorption at 308 nm provides some UV-B coverage not well-served by longer-wavelength hydroxycinnamic acids.

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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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