Chaste Tree (Vitex agnus-castus)

Chaste Tree (Vitex agnus-castus) is not consumed as a food for macronutrient value; its pharmacological relevance derives entirely from its bioactive phytochemical profile. Key Bioactive Compounds: • Iridoid glycosides: Agnuside (0.01–0.07% of dried fruit weight) and aucubin — agnuside is often used as a standardization marker, with quality extracts standardized to ≥0.5% agnuside. • Diterpenes (clerodane-type): Rotundifuran, vitexilactone, and 6β,7β-diacetoxy-13-hydroxy-labda-8,14-diene — these are key dopaminergic active constituents; vitexilactone binds dopamine D2 receptors at concentrations as low as 0.1–1 µM in vitro. • Flavonoids: Casticin (0.02–0.2% of dried fruit), penduletin, chrysosplenol-D, and vitexin. Casticin demonstrates anti-inflammatory and antiproliferative activity. • Essential oils (0.5–1.8% of dried fruit): 1,8-cineole (8–25%), sabinene (5–15%), α-pinene, β-caryophyllene, and limonene — composition varies by geographic origin. • Phenolic acids: p-Hydroxybenzoic acid, chlorogenic acid. • Fatty acids in seed oil: Linoleic acid, oleic acid, palmitic acid, and stearic acid present in seeds but not typically extracted in standard preparations. Standardization of Commercial Extracts: Most clinical trials use BNO 1095 or Ze 440 extracts standardized to contain specific ratios of casticin (≥0.6 mg per 20 mg extract in Ze 440) or agnuside. Typical extract ratios are 6–12:1 (drug:extract) using 60–70% ethanol. Mineral/Vitamin Content: Negligible at therapeutic doses (typically 20–40 mg extract/day or 30–40 mg dried fruit); trace amounts of potassium, calcium, iron, and zinc are present in whole fruit but are pharmacologically irrelevant at standard dosing. Bioavailability Notes: Oral bioavailability of key diterpenes and iridoids is moderate; agnuside undergoes hydrolysis in the GI tract, releasing the aglycone aucubigenin. Casticin has relatively low aqueous solubility, but ethanol-based extraction significantly improves its recovery. The lipophilic diterpene fraction responsible for dopaminergic activity is well-absorbed with concurrent dietary fat. No published human pharmacokinetic studies with full ADME data exist; most bioavailability data are extrapolated from in vitro permeability models and rodent studies.