The dried fruits of the chaste tree Vitex agnus castus (VAC) were traditionally used by monks as a substitute for pepper and was therefore also called Monk’s pepper. For the last 50 years it is commercially provided for the treatment of premenstrual symptoms, particularly to prevent premenstrual mastodynia (mastalgia). Most studies were performed with the preparation containing an aqueous/ethanolic ectract BNO 1095. A number of placebo controlled studies gave proof that extracts of VAC had beneficial effects on premenstrual breast pain. This breast sensation is induced by latent hyperprolactinemia which is characterized by secretory episodes of prolactin release by the pituitary in response to stress and deep sleep phases. This latent hyperprolactinemia induces also often a corpus luteum insufficiency which is a common reason for infertilty.
It is well accepted that prolactin release can be reduced by dopamine and dopaminergic drugs. The efficacy of VAC extracts to ameliorate prolactin induced premenstrual mastodynia was therefore suggestive that VAC may contain dopaminergic compounds. Indeed, a number of diterpenes were identified that bound to recombinant Dopamine receptors of the 2 subtype (D2 receptors) which are present in pituitary lactotropes and which mediate the inhibitory effects of dopamine and dopaminergic drugs on pituitary prolactin release. Consequently, prolactin release in vitro from dispersed pituitary cells and in vivo in rats and postmenopausal women was inhibited by VAC 1095. Placebo controlled studies proved also the efficacy of VAC extracts to ameliorate premenstrual symptoms. In several placebo-controlled studies a clear relation between reduction of breast pain and reduction of serum prolactin levels could be established. In addition VAC extracts was also highly effective in women suffering from fibrocystic mastopathy. In many of these women serum prolactin levels were also elevated and reduced by VAC extracts.
The results from all trials suggested that VAC extracts ameliorated premenstrual symptoms including mastodynia, premenstrual dysphoric disorder and latent hyperprolactinemia. Cystic mastopathy and sterility due to corpus luteum insufficiencies were also beneficially influenced.
Adverse events with VAC were mild and generally infrequent.