Studies on the Constituents of Formosan Salvia Plebeia R. Br. (I) On the Flavonoid Components of Salvia Plebeia R. Br.

Salvia plebeia R. Br. is an annual herb of Labiatae and is widely distributed in the central area of Taiwan. It has been used as folk-medicine for the treatment of hepatitis and tumors.¹⁾ From the flavonoid enriched fraction (B) of the alcoholic extracts of this plant, four kinds of flavonoid compound were isolated. Two of these were confirmed as 5,4′-dihydroxy-6-methoxy-7-glucosyloxy flavone (I). (homoplantaginin, hispidulin-7-glucoside) and 5, 7, 4′-trihydroxy-6-methoxy flavone (II) (hispidulin) on the basis of their spectral, chemical evidences and comparison with authentic samples. The other two were assigned to be 5, 3′, 4′-trihydroxy-6-methoxy-7-glucosyloxy flavone (III) (nepitrin, eupafolin-7-glucoside) and 5,7,3′,4′-tetrahydroxy-6-methoxy flavone (IV) (eupafolin, nepetin) on the basis of chemical and spectral properties. The flavones, II (hispidulin) and IV (eupafolin), have been shown to have cytotoxic activity against human carcinoma of the nasopharynx carried in cell culture (KB).¹³⁾