Studies on the Constituents in the Water Extracts of Crude Drugs. I. On the Roots of Scutellaria baicalensis GEORGI (Wogon) (1)

From the ether-soluble fraction of the water extracts of the roots of Scutellaria baicalensis GEORGI (Japanese name "Wogon"), two new flavone derivertives, named skullcapflavone-I and -II were isolated along with β-sitosterol, campesterol, stigmasterol, wogonin, baicalein, and oroxylin-A (5, 7-dihydroxy-6-methoxyflavone). The chemical structures of skullcapflavone-I (V) and -II (VI) were established as 2', 5-dihydroxy-6, 8-dimethoxyflavone and 2', 5-dihydroxy-6, 6', 7, 8-tetramethoxyflavone, respectively, by chemical and physical analyses.