Flavonoids from the Leaves of Nicotiana tabacum and Their Anti-Tobacco Mosaic Virus Activity

Three new flavonoids, 8-formyl-4'-hydroxy-7-methoxy-6-methylflavone (1), 8-formyl-4',7-dimethoxy-6-methylflavone (2), 4',6-dihydroxy-7-methoxy-8-methoxycarbonylflavone (3) together with two known flavonoids (4 and 5) were isolated from the leaves of Nicotiana tabacum.Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies.Compounds 1-3 were tested for their anti-tobacco mosaic virus (anti-TMV) activities.The results showed that compounds 1-3 exhibited