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-beta-D-glucopyranoside, 5,7,2'-trihydroxy-8-methoxyflavone 2'-O-beta-D-glucopyranoside, 5,7-dihydroxy-8,2'-dimethoxyflavone 7-O-beta-D-glucopyranoside, 5,7,2'-trihydroxyflavone 2'-O-beta-D-glucopyranoside, 5,7,2',5'-tetrahydroxyflavone 7-O-beta-D-glucuronopyranoside, (2S)-5,7,2',5'-tetrahydroxyflavanone, (2S)-5,7,2',5'-tetrahydroxyflavanone 7-O-beta-D-glucopyranoside, (2S)-5,7,2',5'-tetrahydroxyflavanone 7-O-beta-D-glucuronopyranoside, (2S)-7,2'-dihydroxy-5-methoxyflavanone 7-O-beta-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-beta-D-glucuronopyranoside. The structures were determined on the basis of chemical and spectral data.