ABSTRACT
Commercial products of VAC are prepared from the dried, ripe fruit, containing not less than 0.4% (v=w) of volatile oil and at least an 8% water-soluble extractive.[1,22] To date, although the active constituents of VAC remain unknown, the European Pharmacopoeia recommends a minimum content of 0.08% casticin in the dried plant material.[23] Two compounds are currently used as marker compounds for quality control, the iridoid glycoside agnuside and the flavonol casticin.[24] Most vitex preparations used in European medicine are nonstandardized fluid extracts, tinctures, and=or native dry extracts. The ‘‘native’’ or ‘‘total’’ extract is an approximate 10 : 1 (w=w) drug-to-extract ratio containing 0.6-1.0% casticin.[2]
The ripe, dried vitex fruit yields 0.4-0.7% (v=w) essential oil, depending on distillation time and comminution size. The oil is mainly composed of bornyl acetate, 1,8-cineole, limonene, a-and b-pinene, b-caryophyllene, and a-terpinyl acetate.[25] Flavonoids, iridoids, and diterpenes represent major groups of secondary constituents also found in the fruit.[2]
Casticin (up to 0.2%) is considered to be the major flavonoid, with chrysoplenetin, chrysosplenol D, cynaroside, 5-hydroxy-3,40,6,7-tetramethoxyflavone, 6-hydroxykaempferol, isorhamnetin, luteolin, and luteolin 6-C-glycoside derivatives being other compounds of this class.[25-27] Major iridoids found include agnuside (p-hydroxybenzoylaucubin, 0.0014%) and aucubin (0.0013%). Diterpene constituents include vitexilactone (0.001-0.004%), 6b,7b-diacetoxy-13hydroxylabda-8,14-diene, rotundifuran, vitexlabdines
A-D, and vitexlactam A.[25,26] The structures of the above-mentioned components are presented in Fig. 1.
