Sinapic acid

Sinapic acid is a hydroxycinnamic acid phenylpropanoid compound (molecular formula C11H12O5, MW 224.21 g/mol), not a whole food ingredient, so traditional macronutrient/micronutrient profiling does not apply. As a purified bioactive compound, it is relevant in trace dietary concentrations. Naturally occurring concentrations in food sources: rapeseed/canola meal (8–12 mg/g dry weight, one of the richest sources), mustard seeds (~1–5 mg/g), broccoli (~0.5–2 mg/g fresh weight), Brussels sprouts (~0.3–1.2 mg/g fresh weight), and kale (~0.2–0.8 mg/g fresh weight). Found primarily as sinapine (sinapic acid choline ester) in Brassica seeds, requiring enzymatic hydrolysis for release. Bioavailability is limited and variable: oral bioavailability estimated at 10–30% in animal models, with significant first-pass metabolism; human pharmacokinetic data are sparse. Absorbed primarily in the small intestine via passive diffusion; colonic microbiota further metabolize it to dihydrosinapic acid and other phenolic metabolites. Plasma Cmax reported in rodent studies at approximately 1–5 µM following doses of 20–50 mg/kg. Rapidly conjugated to glucuronide and sulfate forms in plasma. No meaningful caloric, protein, fat, fiber, vitamin, or mineral contribution at physiologically relevant dietary doses. Key bioactive properties linked to its methoxy and hydroxyl substituents on the phenylpropanoid backbone, which confer radical-scavenging capacity (DPPH IC50 approximately 15–30 µM in vitro).