In vivo Effects of Black Cohosh and Genistein on Estrogenic Activity and Lipid Peroxidation in Japanese Medaka (Oryzias latipes)

Abstract

This study was designed to assay the estrogenic activities and the antioxidant potential of ethanol extracts from the herbal dietary supplement black cohosh (Cimicifuga racemosa) relative to the natural phytoestrogen genistein. The in vivo mechanisms of action of these two natural products have not been completely elucidated, and Japanese medaka (Oryzias latipes) provides a useful organism for initial in vivo screening of natural products. While both genistein and estradiol altered ovarian and testicular steroid release and decreased circulating testosterone levels in males, neither black cohosh total extract (75-30,000 ng/fish), cimiracemoside A, 25-O-methyl-cimigenoside, actein, nor 26-deoxy-actein caused any differences in estrogenic activity compared to control fish. To assess antioxidant potential, animals were treated with natural products then challenged with 2-acetylaminofluorene (2-AAF) to induce lipid peroxidation (LPO) in the liver. Neither the total ethanol extracts from black cohosh nor its individual components showed an inhibitory effect in 2-AAF induced LPO. However, genistein manifested potent antioxidative activity in the LPO assay, with similar potency to a high dose of á-tocopherol. In contrast to genistein, black cohosh did not exhibit traditional estrogenic effects nor significant in vivo anti-oxidant potential in this fish model system.

Synergistic cytotoxic effects of tamoxifen and black cohosh on MCF-7 and MDA-MB-231 human breast cancer cells: an in vitro studyThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

“…In fact, several placebocontrolled clinical trials, mainly in Germany, conducted with healthy women, suggest that black cohosh alleviates somatic and psychological symptoms associated with menopause (Foster 1999). The results of the most recent studies confirm the absence of any estrogenic effect of black cohosh (Li and Yu 2006); (Zhang et al 2003); (Bodinet and Freudenstein 2002); (Liske et al 2002). Black cohosh does not change levels of estradiol (E 2 ), follicle-stimulating hormone (FSH), or luteinizing hormone (LH) and does not affect vaginal maturation (changes in vaginal epithelial cell morphology) (Liske 1998).…”