Quantitative high performance liquid chromatographic analysis of casticin in the fruits of Vitex agnus-castus

Using the radioligand-dopamine D2-receptor-in vitro test, the lipophilic fraction of the crude methanol extract of Agni-casti fructus, in contrast to the hydrophilic fraction, was shown to contain the active principle of Agni-casti preparations. Therefore, casticin, a lipophilic flavonoid and often the main compound in the 270 nm fingerprint chromatogram of a methanol extract, was selected as the relevant lead compound for quantitative analyses. An HPLC method was developed and validated to quantify the amount of casticin in eight commercial drug samples of Agni-casti fructus. A selective separation was achieved using a RP-C18-column with methanol-phosphate buffer-gradient as the mobile phase. The concentration of casticin in the samples varied from 0.025 to 0.212%. An additional minor peak was identified by LC-MS as penduletin.