[Antifeedant and antioviposition activities of Momordica charantia leaf ethanol extract against Liriomyza sativae].

Liriomyza sativae Blanchard (Diptera: Agromyzidae) is one of the important pests harming a wide variety of vegetables and ornamental plants throughout the world. The leaf ethanol extract of Momordica charantia at the concentration of 2000-4000 microg x ml(-1) displayed significant antifeedant and antioviposition activities against L. sativae adults. For further purifying the extract, four solvents, i. e., cyclohexane, ethyl acetate, n-butanol and water, were used to extract the ethanol extract, and the antifeedant and antioviposition activities of the extracts against L. sativae adults were tested. The results showed that after treated with the extracts at the concentration of 1000 microg x ml(-1) for 2 days, the antifeedant index (AFI) of cyclohexane-, ethyl acetate-, n-butanol- and water extracts against L. sativae adults was 11.08%, 34.89%, 22.99% and 0, and the antioviposition index (AOI) was 0, 30.91%, 6.45% and 0, respectively. Ethyl acetate extract had the highest bioactivity. At the concentration of 4000 microg x ml(-1), the AFI and AOI of ethyl acetate extract were 70.95% and 69.49%, respectively. The ethyl acetate extract was then isolated by silica gel column chromatography, and three compounds, i.e., (19S, 23E)-5beta,19-epoxy-19-methoxy-cucurbita-6,23-dien-3beta and 25-diol (compound 1), (19R, 23E)-5beta,19-epoxy-19-methoxy-cucurbita-6,23-dien-3beta and 25-diol (compound 2), and 3beta, 7beta,25-trihydroxycucurbita-5,23-dien-19-al-3-O-beta-D-glucopyranoside (compound 3), were obtained. These three compounds at concentration of 100-400 microg x ml(-1) all had inhibitory effects on the feeding and oviposition of L. sativae. At the concentration of 400 microg x ml(-1), the AFI and AOI were 66.89% , 53.53% and 78.02% , and 76.32%, 58.36% and 78.36% for compound 1, 2 and 3, respectively.