Scuteflorins A and B, dihydropyranocoumarins from Scutellaria lateriflora.

Two new dihydropyranocoumarins, scuteflorins A (1) and B (2), together with the known compounds decursin (3), chrysin (4), oroxylin A (5), wogonin (6), 5,7-dihydroxy-8,2'-dimethoxyflavone, dihydrochrysin, dihydrooroxylin A, lupenol, scutellaric acid, pomolic acid, ursolic acid, beta-sitosterol, daucosterol, and palmitic acid, were isolated from the aerial parts of Scutellaria lateriflora, commonly used as a dietary supplement. The structures of 1 and 2 were established by means of 1D and 2D NMR spectra as well as HRMS data. The absolute configuration of coumarins 1 and 2 was determined by comparison of experimental and theoretical calculated CD spectra. The cytotoxicity and antioxidant effects of the methanol extract of this plant and some of the constituent flavonoids were evaluated in vitro.