摘要

A new isoflavonoid (3',4',5'-trihydroxyl-5,7-dimethoxyl-isoflavonoid) was isolated from the stems of Nicotiana tabacum. Its structure I I was determined by means of HRESIMS, extensive D-1 and D-2 NMR spectroscopic studies and chemical evidences. The anti-tobacco mosaic virus activity of the new isoflavonoid was also evaluated and it shows moderate anti-tobacco mosaic virus activity.