薇苷菊提取物对桔全爪螨的产卵驱避作用及有效组分分析

Study on the active components of oviposition repellency of Mikania micrantha H.B.K. against citrus red mite, Panonychus citri McGregor

使用甲醇、乙酸乙酯、乙醚提取薇苷菊 Mikania micrantha H.B.K.地上部植株并测试 3种提取物对桔全爪螨 Panonychuscitri Mc Gregor产卵的驱避作用 ,结果发现这些提取物处理后 1d都有显著的产卵驱避效果 ,其中极性最强的甲醇提取物效果最好 ,处理后 1d的产卵驱避率为 74 .2 2 %。用乙醚、乙酸乙酯、正丁醇、水依次对薇苷菊甲醇提取物进行萃取 ,生测结果表明只有极性最强的水萃取物具有显著的产卵驱避效果。进一步研究发现薇苷菊甲醇提取物经柱层析分离得到的 6个组分中有 3个对桔全爪螨有显著的产卵驱避作用 ,但效果都不及提取物 ,说明薇苷菊对桔全爪螨的产卵驱避作用是各组分共同作用的结果。用GC- MS对最有效组分的分析表明 :2 ,2′-亚甲基双 (6 -叔丁基 - 4 -甲基 )苯酚是含量最大的成分 ,占 70 .2 4 % ,β-谷甾醇和岩藻甾醇也是有效成分 ,但含量较低 ,分别占 12 .0 3%和 5 .6 1%

Citrus red mite Panonychus citri McGregor became a major pest of citrus in China during the late 1950s. The widespread use of synthetic pesticides since then has greatly reduced natural enemies in the citrus orchard and resulted in widespread resistance of citrus red mite, making it the most difficult citrus pest to control. New, effective control methods for citrus red mite are urgently needed. One possible avenue is the use of active components from plant secondary metabolites to control herbivorous pests. Secondary metabolites play an important role in plant defense systems. Recent studies showed that the volatiles oil from the noxious weed mile-a-minute, Mikania micrantha H.B.K., had significant biological activity on insects, plants and fungi. In this study we used different solvents to extract non-volatile secondary metabolites from M. micrantha and investigated the oviposition repellency of these extracts to citrus red mite. Methanol,ethyl acetate and ethyl ether extracts of M. micrantha all significantly reduced oviposition of citrus red mite 1d after treatment in a choice test. Methanol, the strongest polarity solvent extract resulted in the highest repellency rate of 74.22%. A range of different solvents including ethyl ether,ethyl acetate,n-butanol methanol and water were then used to extract this methanol extract. Bioassay showed that only water, the strongest polarity solvent fraction showed significant oviposition repellency, with a repellency rate of (65.33%) 1d after treatment. The methanol extract of M. micrantha was separated by chromatographic column and 6 fractions were isolated. Bioassay demonstrated that the oviposition repellency of these fractions was not as strong as the crude extract, and that the active components were in different fractions. Among them, the first fraction (F_1) was the most active with a repellency rate of 61% 1d after treatment, demonstrating that the active compounds were largely maintained. GC-MS analysis showed that three of the compounds in this fraction were 2,2′-Methylenebis[6-(1,1-dimethylethyl)-4-methyl]Phenol, β-Sitosterol and Fucosterol and they made up 70.24%,12.03% and 5.61% of the fraction respectively.