Insecticidal activities and active ingredients of pronephrium megacuspe | 微红新月蕨的杀虫活性和活性组分的分离及鉴定

中国人. 【目的】研究微红新月蕨（Pronephrium megacuspe）的杀虫成分并对其进行分离、鉴定。【方法】通过生物活性测定确定微红新月蕨提取物对几种害虫的杀虫活性及其作用方式，并在活性跟踪的基础上，通过萃取、柱层析、薄层层析制备、重结晶、核磁共振和质谱等方法对活性组分进行分离和鉴定。【结果】微红新月蕨甲醇提取物对家蝇成虫（Musca domestica）、白纹伊蚊4龄幼虫（Aedes albopictus）、桃蚜（Myzus persicae）具有较好的毒杀活性，对小菜蛾（Plutella xylostella）、亚洲玉米螟（Ostrinia furnacalis）和菜粉蝶（Pieris rapae）3龄幼虫具有拒食活性。从微红新月蕨甲醇提取物中分离和鉴定了4种化合物，即7-羟基-5-甲氧基-6,8-二甲基黄烷酮、2',4'-二羟基-3'-甲基-6'-甲氧基查尔酮、5,7-二羟基-6,8-二甲基黄烷酮和5-羟基-6,7-二甲氧基黄酮。上述4种化合物在50 mg•L-1的浓度下，对亚洲玉米螟3龄幼虫都具有拒食活性；5,7-二羟基-6,8-二甲基黄烷酮对小菜蛾3龄幼虫具有较弱的拒食活性，24 h的平均拒食率为40.51%，另外3种化合物对小菜蛾3龄幼虫没有拒食活性；2 ?g/头的剂量下，这4种化合物对亚洲玉米螟3龄幼虫没有触杀活性，24和48 h的平均死亡率为0；1 ?g/头的剂量下，5,7-二羟基-6,8-二甲基黄烷酮对小菜蛾3龄幼虫48 h的平均死亡率为33.76%，另外3种化合物对小菜蛾3龄幼虫也基本没有触杀活性。【结论】微红新月蕨甲醇提取物对多种害虫具有较高的活性，从该植物中已分离鉴定出的4种化合物母体结构一致，但取代基不同或取代的位置不同，其活性也有明显的差异。因此，微红新月蕨中其它化学成分及其构效关系值得深入的研究。

英语. 【Objective】 The objective of this study is to research the active ingredients of Pronephrium megacuspe.【Method】Insecticidal activities and action mode were determined by bioassay. The active ingredients were isolated from the extract by activity-guided fractionation with column chromatography, thin layer chromatography (TLC) and recrystallization, and the structures were identified predominantly on the basis of MS and NMR data.【Result】The results showed that the methanol extract of P. megacuspe possessed toxicity against the adult of Musca domestica, the 4th instar larva of Aedes albopictus and Myzus persicae, and had antifeedant activity to the 3rd instar lavae of Plutella xylostella, Ostrinia furnacalis and Pieris rapae. 7-hydroxy-5-methoxy -6,8-dimethyl-flavanone, 2′,4′-dihydroxy-3′-methyl-6′-methoxychalcone, 5,7-dihydroxy-6,8-dimethylflavanone and 5-hydroxy-6,7- dimethoxyflavone were isolated and identified from the methanol extract of P. megacuspe. The results of bioassay showed that all compounds possessed antifeedant activity to the 3rd instar lavae of O. furnacalis with the average antifeedant rate above 50% at a concentration of 50 mg•L-1 at 24 h after treatment. Four compounds exhibited no contact activity against the 3rd instar lavae of O. furnacalis at a dosage of 2 ?g/pest. 5,7-dihydroxy-6,8-dimethylflavanone possessed weak antifeedant activity against the 3rd instar lavae of P. xylostella with an average antifeedant rate of 40.51% at 24 h after treatment, and the mortality was 33.76% at a dosage of 1 ?g/pest at 48 h after treatment. The other three compounds had no contact toxicity to the 3rd instar lavae of P. xylostella. 【Conclusion】P. megacuspe has insecticidal activities against various insect pests. Four compounds were isolated and identified from the methanol extract of P. megacuspe. They have the similar mother structure, but different on the number of replaced methylium and its place, and have different activities. Therefore the other compounds and the structure-activity relationship of P. megacuspe need to be further investigated as a biopesticide.