Two New Chromone Derivatives from Cassia nomame and their Anti-Tobacco Mosaic Virus Activity

Two new chromone derivatives, 5-(isobutyryl)-2-(2-oxopropyl)-7-methoxy-4H-chromen-4-one (1) and 5-(isobutyryl)-2-(2-oxopropyl)-6-methoxy-4H-chromen-4-one (2), were isolated from Cassia nomame. 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 showed potential anti-TMV activities with inhibition rates of 28.7% and 31.2%, at the concentration of 20 μM, respectively. These rates are close to that of positive control.