Studies on the Constituents of Scutellaria Species (XXII). Constituents of the Roots of Scutellaria amabilis HARA

From the roots of Scutellaria amabilis HARA, eleven new flavonoids, 5,7,2′-trihydroxy-8-methoxyflavone 7-O-β-D-glucopyranoside, 5,7,2′-trihydroxy-8-methoxyflavone 2′-O-β-D-glucopyranoside, 5,7-dihydroxy-8,2′-dimethoxyflavone 7-O-β-D-glucopyranoside, 5,7,2′-trihydroxyflavone 2′-O-β-D-glucopyranoside, 5,7,2′,5′-tetrahydroxyflavone 7-O-β-D-glucuronopyranoside, (2S)-5,7,2′,5′-tetrahydroxyflavanone, (2S)-5,7,2′,5′-tetrahydroxyflavanone 7-O-β-D-glucopyranoside, (2S)-5,7,2′,5′-tetrahydroxyflavanone 7-O-β-D-glucuronopyranoside, (2S)-7,2′-dihydroxy-5-methoxyflavanone 7-O-β-D-glucuronopyranoside, (I-2S)-I-5,II-5,I-7,II-7,I-2′,II-2′,II-5′-heptahydroxy-[I-6,II-6′]-flavanonylflavone and (I-2S)-I-5,II-5,I-7,II-7,I-2′,II-2′,I-5′,II-5′-octahydroxy-[I-6,II-6′]-flavanonylflavone, were isolated, together with ten known flavonoids, wogonin (5,7-dihydroxy-8-methoxyflavone), 5,7-dihydroxy-8,2′-dimethoxyflavone, (2S)-5,7,2′-trihydroxyflavanone, scutevulin (5,7,2′-trihydroxy-8-methoxyflavone), 5,7,4′-trihydroxy-8-methoxyflavone, alpinetin ((2S)-7-hydroxy-5-methoxyflavanone), 5,7,2′-trihydroxyflavone, 5,7,2′,5′-tetrahydroxyflavone, (2S)-7,2′-dihydroxy-5-methoxyflavanone and 5,7-dihydroxy-8,2′-dimethoxyflavone 7-O-β-D-glucuronopyranoside. The structures were determined on the basis of chemical and spectral data.