Chromone Derivatives from the Leaves of Nicotiana tabacum and Their Anti-Tobacco Mosaic Virus Activities

Abstract

Two new chromone derivatives, 5-hydroxy-9-methyl-1-(2oxopropyl)benzo[β]oxepin-7(2H)-one (1), 5-hydroxy-2-methoxy-9-methyl-1-(2-oxopropyl)benzo[β]oxepin-7(2H)-one (2), together with five known chromone derivatives (3-7), were isolated from the leaves of Nicotiana tabacum.Their structures were elucidated by spectroscopic methods, including extensive 1D-and 2D-NMR techniques.Compounds 1-7 were tested for their anti-tobacco mosaic virus (anti-TMV) activities.The results showed that compound 2 exhibited high anti-TMV activity with inhibition rate of 31.5%.Its inhibition rate is close to that of positive control.The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 11.2  23.5%.Nicotiana tabacum, tobacco, is a stout herbaceous plant in the Solanaceae (nightshade family) that originated in the tropical Americas (South America, Mexico, and the West Indies) and now cultivated worldwide as the primary commercial source of tobacco, which is smoked or chewed as a drug for its mild stimulant effects. 1,2In addition, N. tabacum is also used as insecticides, anesthetics, diaphoretics, sedatives, and emetic agents in Chinese folklore medicines because of its containing many useful chemical compounds. 1,35][6][7][8][9] With the aim of continuing efforts to utilize N. tabacum