Two New Flavones from Cassia pumila and Their Anti-Tobacco Mosaic Virus Activity

Two new flavones, 8-hydroxy-7-(3-hydroxypropyl)-2′-methoxyflavone (1) and 8-hydroxy-7-(2-hydroxyethyl)-2′-methoxyflavone (2), together with four known flavones (3–6), were isolated from the whole plants of Cassia pumila. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that compounds 1 and 2 have potential anti-TMV activities with inhibition rates of 30.2% and 28.2%, respectively.