Breviflavone found in horny goat weed herb

Determination of breviflavone A and B in Epimedium herbs with liquid chromatography-tandem mass spectrometry.
J Pharm Biomed Anal. 2009 Apr 5; Hong X, Wang X, Yong EL, Gong Y. 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 0.179% for breviflavone A and 0.0026 to 0.0252% for breviflavone B in the dried ethanolic extracts of those Epimedium herbal samples.