Breviflavone found in horny goat weed herb and benefit
Determination of breviflavone A and B in
Epimedium herbs with liquid
chromatography-tandem mass spectrometry.
J Pharm Biomed Anal. 2009; Hong X, Wang X, Yong EL. Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore.
Two new types of minor flavonoids, breviflavone A and B, have been recently isolated and identified from Epimedium brevicornu in our previous research. Breviflavone B is a novel flavonoid with potent and specific estrogen receptor (ER) bioactivity. Its positional isomer, breviflavone A, is not ER active. Therefore, it is important to determine the two minor components, breviflavone A and B, in Epimedium herbs. In this report, a robust method for measurement of the two breviflavones in Epimedium ethanolic extracts has been developed by using liquid chromatography tandem mass spectrometry via selected-reaction monitoring. This method has been successfully used to determine the two breviflavones in ethanolic herbal extracts of five major Epimedium species (E. brevicornu, E. koreanum, E. pubescens, E. sagittatum, and E. wushanese) from various sources. The contents of the two breviflavones range from 0.018 to 0.17% for breviflavone A and 0.002 to 0.025% for breviflavone B in the dried ethanolic extracts of those Epimedium herbal samples.
Phytochemistry. 2007. Taxonomic, genetic, chemical and estrogenic characteristics of Epimedium species. Department of Obstetrics and Gynecology, National University Hospital, Yong Loo Lin School of Medicine, Lower Kent Ridge Road, Singapore, Republic of Singapore. To understand the factors contributing to estrogenic properties of extracts from the genus Epimedium, we performed taxonomic, genetic and chemical characterization on 37 specimens from 18 species and related these to estrogen receptor (ERalpha and ERbeta) bioactivity, as measured by reporter genes in stable human cells. Boot strap values derived from amplified fragment length polymorphisms indicated that specimens of E. koreanum, E. brevicornum, E. myrianthum, E. leishanense, and E. membranaceum were genetically distinct and this was supported by their very similar ERalpha activities. In contrast, specimens from E. pubescens and E. sagittatum were diverse both genetically, chemically and in terms of ERalpha and ERbeta bioactivities. Strikingly, a genetic cluster comprising six rare Epimedium species exhibited strongest ERalpha and ERbeta activity, and this bioactivity was positively correlated with content of trace flavonoid aglycones (kaempferol, apigenin, quercetin, luteolin and breviflavone B). In contrast, there was no association between estrogenic activity and the major flavonol glycoside constituents (icariin and epimedin A-C). Although they exhibited equally strong ERalpha and ERbeta activity, E. koreanum can be clearly differentiated from E. pubescens and E. brevicornum by genetic distance and its significantly lower content of epimedin C. Our morphologic, genetic, chemical and bioactivity profiling provide the basis for the production of extracts with reproducible estrogenic properties. Such reproducibility will be critical for the standardization of Epimedium-based products.
Planta Med. 2005. New estrogenic prenylflavone from Epimedium brevicornum inhibits the growth of breast cancer cells. Department of Obstetrics and Gynecology, National University of Singapore, Republic of Singapore. Estrogens maintain female sexual health. The hormone also drives the growth of estrogen receptor (ER) positive breast tumors, and ER modulators, like tamoxifen, are used to reduce tumor recurrence. To identify phytoestrogens with possible health benefits, we screened several Traditional Chinese Medicines and encountered an extract from the leaves of Epimedium brevicornum (EB), with strong (EC50: 1.3 microg/mL) and specific ER-stimulatory activity. It increased estrogen-responsive human breast cancer cell proliferation at low doses, but paradoxically caused profound inhibition of growth at higher doses. Using bioassay-guided fractionation, we isolated and characterized a new prenylflavone, breviflavone B, which exerted biphasic stimulatory and inhibitory effects on breast cancer cell proliferation, mimicking the effects of EB. In contrast to estradiol and genistein, high doses (> 2 microM) of breviflavone B almost eliminated ERalpha protein; a process that may be mediated through increased proteasome degradation. Pre-clinical studies are needed to explore whether these prenylflavones are of value in estrogen-deficiency states and for prophylaxis of breast cancer.