Nervione, a new benzofuran derivative from Nervilia concolor

A new benzofuran derivative, nervione (1), was isolated from Nervilia concolor (Blume) Schltr. (Orchidaceae). Eight previously reported compounds were also isolated: 5,7-dimethoxyflavone (2), 3,5,7-trimethoxyflavone (3), 7-methoxyflavone (4), 3,7-dimethoxy-5-hydroxyflavone (5), tetramethylscutellarein (4',5,6,7-tetramethoxyflavone) (6), 5,7-dimethoxy-4'-hydroxyflavone (7), rhamnetin (8), and 5,7-dihydroxy-3',4'-dimethoxyflavone (9). The structures were elucidated by 1D, 2D NMR, and HRESIMS spectroscopy in addition to the literature. The relative configuration of 1 was defined using DP4+ probability while its absolute configuration was defined by comparison of the ECD spectrum of 1 with those of previously reported compounds. All isolated compounds were evaluated for alpha-glucosidase inhibition, revealing weak or no activity.