苦瓜叶提取物对美洲斑潜蝇取食和产卵行为的抑制作用

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

美洲斑潜蝇是危害蔬菜、观赏植物的重大害虫之一.苦瓜叶乙醇提取物(浓度为2000～4000μg.ml-1)对美洲斑潜蝇成虫的取食和产卵都具有较强的抑制作用.用环己烷、乙酸乙酯、正丁醇和水依次对乙醇提取物进行萃取,并测试了4种萃取物对美洲斑潜蝇成虫取食和产卵的抑制作用.结果表明:环己烷、乙酸乙酯、正丁醇和水萃取物在浓度为1000μg.ml-1时,处理后2d对美洲斑潜蝇成虫的拒食率分别是11.08%、34.89%、22.99%和0,产卵抑制率分别是0、30.91%、6.45%和0.其中,乙酸乙酯萃取物的活性最强,当其浓度为4000μg.ml-1时,处理后2d对美洲斑潜蝇成虫的拒食率和产卵忌避率分别为70.95%和69.49%.乙酸乙酯萃取物经硅胶柱层析分离得到(19S,23E)-5β,19-环氧-19-甲氧葫芦素-6,23-二烯-3β,25-二醇(化合物1)、(19R,23E)-5β,19-环氧-19-甲氧葫芦素-6,23-二烯-3β,25-二醇(化合物2)和3β,7β,25-三羟基葫芦素-5,23-二烯-19-醛缩-3-O-β-D-吡喃葡糖苷(化合物3),3种化合物在供试的浓度(100～400μg.ml-1)条件下对美洲斑潜蝇的取食和产卵行为都有明显的抑制作用.在400μg.ml-1浓度时,化合物1、化合物2和化合物3对美洲斑潜蝇成虫的拒食率分别是66.89%、53.53%和78.02%,产卵抑制率分别是76.32%、58.36%和78.36%.

Liriomyza sativae Blanehard （Diptera： Agromyzidae） is one ot 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 2000-4000μg·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 1000μg·ml^-1 for2 days, the antifeedant index （AFI） of eyclohexaneethyl 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 high- est bioactivity. At the concentration of 4000μg·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）-5β,19-epoxy-1β-metlaoxy-cueurbita-6,23 -dien-3β and 25-diol （ compound 1 ）, （ 19R, 23E） -5β,19-epoxy-19-methoxy-cucurbi- ta-6,23-alien-3β and 25-diol （ compound 2 ）, and 3β,7 β,25-trihydroxycucurbita-5,23-alien-19-al- 3-O-β-D-glucopyranoside （compound 3 ） , were obtained. These three compounds at coneentration of 100-400 μg·ml^-1 all had inhibitory effects on the feeding and oviposition of L. sativae. At the concentration of 400μg·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.