Botanical, chemical, genetic, and pharmacological studies of Vitex agnus-castus L

Chasteberry is a botanical dietary supplement made from the dried ripe fruit of Vitex agnus-castus L. and is primarily used to alleviate symptoms of premenstrual syndrome (PMS). Most evidence indicates that Vitex agnus-castus elicits its effects through activation of dopamine D2 receptors to reduce serum prolactin, however other pathways may also be involved. Vitex rotundifolia L.f., V. trifolia L., and V. negundo L. are three other common medicinally used Vitex species that are sometimes substituted for V. agnus-castus for the treatment of PMS. Although it is possible that V. rotundifolia, V. trifolia, and V. negundo may also alleviate symptoms of PMS, only Vitex agnus-castus has been clinically studied and found to be effective for this condition. Therefore, this study is composed of three specific aims that examine both authentication and pharmacology of Vitex agnus-castus . The first aim was to determine the best botanical, chemical, and genetic methods for distinguishing Vitex agnus-castus from Vitex rotundifolia, Vitex trifolia, and Vitex negundo. The second aim was to determine if V. agnus-castus activates opioid receptors as a possible partial mechanism of action in the treatment of PMS. Because V. rotundifolia, V. trifolia, and V. negundo have been prescribed in Chinese and Ayurvedic medicine to treat various conditions of pain, the third aim of this project was to determine if these species may also elicit their analgesic effects through activation of opiate receptors and to compare this activity to that of V. agnus-castus. Results suggest a combination of botanical, chemical, and biological techniques are needed to distinguish V. agnus-castus from V. rotundifolia , V. trifolia, and V. negundo. Although all four Vitex species appear to have affinity and activity at mu opioid receptors (MOR) and delta opioid receptors (DOR), V. agnus-castus and V. negundo demonstrated the most potent activity at MOR, and V. agnus-castus demonstrated the most potent activity at DOR. The compound casticin may be partially responsible for this activity at DOR. This research is important in order to properly identify and standardize Vitex agnus-castus products to improve and ensure their efficacy.