Two new sesquiterpenes from the leaves of <i>Nicotiana tabacum</i> and their anti-tobacco mosaic virus activities

<p>Two new sesquiterpenes, nicotianasesterpenes A and B (<b>1</b> and <b>2</b>), together with five known sesquiterpenes (<b>3–7</b>) were isolated from the leaves of <i>Nicotiana tabacum</i>. Their structures were determined mainly by spectroscopic methods, including extensive 1D- and 2D-NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activities of compounds <b>1–7</b> were evaluated. The results revealed that compound <b>1</b> exhibited high anti-TMV activities with inhibition rates of 33.6%. This rate is high than that of positive control. The other compounds also showed potential activities with inhibition rates in the range of 18.8–28.4%, respectively.</p> <p>The structures of compounds <b>1</b>–<b>2.</b>