Isochromenes from the <i>Nicotiana tabacum</i>-derived endophytic fungus <i>Aspergillus versicolor</i> and their anti-tobacco mosaic virus activities
Feng-Xian Yang, Jia-Meng Dai, Hua-Yin Liu, Qi-Li Mi, Jin Wang, Jian-Duo Zhang, Xuemei Li, Wei‐Guang Wang, Min Zhou, Yin-Ke Li, Qiu‐Fen Hu
Abstract
Three new isochromenes, (5-methoxy-7-prenyl-1H-isochromen-3-yl)methanol (1), 3-(3-(hydroxymethyl)-5-methoxy-1H-isochromen-7-yl)propan-1-ol (2), and (5-methoxy-7-methyl-1H-isochromen-3-yl)methanol (3), along with three known analogues (4–6) were isolated from the fermentation products of a Nicotiana tabacum-derived endophytic fungus Aspergillus versicolor. Their structures were elucidated by spectroscopic methods, including extensive 1 D and 2 D NMR techniques. Compounds 1–3 and 6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 2 exhibited high anti-TMV activity with inhibition rate of 46.4%, and this rate is higher than that of positive control. Compounds 1, 3, and 6 also showed potential anti-TMV activity with inhibition rates of 28.6, 30.5, and 26.2%, respectively. The IC50 of compounds 1–3 and 6 were also tested, and showed IC50 values of 49.3, 22.4, 42.2, and 54.1 µM, respectively.