Characterization of phenolic constituents from Ephedra Herb extract

Abstract

Ephedra Herb (Japanese name: mao) is defined as the terrestrial stem of Ephedra species. It is one of the most im­portant crude drugs in Kampo prescriptions such as maoto, kakkonto, and shoseiryuto. The traditional biological properties of Ephedra Herb are mainly attributable to ephedrine alkaloids. Recently, our research group has found that Ephedra Herb extract also shows alkaloid-independent pharmacological action; therefore, we focused on polyphenols, other active ingredients of Ephedra Herb extract. Reports on the constituents of the extract other than ephedrine alkaloids are limited, although condensed tannins of procyanidin A-type have been found in some Ephedra species. To determine the components associated with the antitumor activity of Ephedra Herb extract, we investigated the phenolic compounds in the extract and characterized 10 compounds, including the new compound herbacetin 7-O-neohesperido- side, together with catechins and flavonoids with an apigenin or a herbacetin skeleton, and phenylpropanoids such as syringin. Of the 10 compounds, isovitexin 2ʺ-O-rhamnoside was obtained in the greatest yield. Here, we describe the elucidation of part of the polyphenolic fraction from Ephedra Herb extract.