Dihydrostilbene derivatives from the Mongolian medicinal plant Scorzonera radiata.

Chromatographic separation of a crude extract obtained from aerial parts of the Mongolian medicinal plant Scorzonera radiata yielded five new dihydrostilbenes, scorzodihydrostilbenes A-E (1-5). The structures were unambiguously elucidated on the basis of one- and two-dimensional NMR ((1)H, (13)C, COSY, HMBC, HMQC, and ROESY) and mass spectrometric data. Compounds 1-5 exhibited antioxidative activity when analyzed in the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. For 1 and 5 the antioxidant activities were stronger than that of the well-known naturally occurring stilbene antioxidant resveratrol.