苦豆子生物碱对萝卜蚜的毒力及其对几种酯酶的影响

苦豆子Sophora alopecuroids(L.)的次生代谢物质为喹诺里西定生物碱类。本研究明确了该生物碱中的野靛碱对萝卜蚜(Lipaphis erysimi)有很高的毒杀作用，对其无翅成蚜的致死中浓度(LC₅₀浸渍法)为(432.59±2.12)mg/L，优于著名的杀蚜生物碱毒黎碱和烟碱，两者对该试虫的LC₅₀分别为(684.70±2.28)mg/L和(1090.65±2.01)mg/L。用小菜蛾(Plutella xylostella)幼虫作试虫，得知苦豆子7种主要生物碱对昆虫的乙酰胆碱酯酶(AChE)有抑制作用，其抑制程度排序为：总碱>野靛碱>槐胺碱>槐定碱>槐果碱>氧化苦参碱>苦参碱>苦豆碱。野靛碱和苦豆碱对a-乙酸萘酯酶、a-乙酸萘酯羧酸酯酶及酯酶同功酶的活性亦表现不同程度的抑制作用。

THE TOXICITIES OF ALKALOIDS FROM SOPHORA ALOPECUROIDS AGAINST TURNIP APHIDS AND EFFECT ON SEVERAL ESTERASES

In this paper, the toxicities of seven quinolizidine alkaloids from Sophora alopecuroids against turnip aphids and their effects on several esterases were studied. The results showed that one of the alkaloids cytisine is highly effective against the insect than anabasine and nicotine which are famous aphidcides. The median lethal concentrations of the alkaloids against the apterous aphid are 432.59, 684.70 and 1 090.65 mg/L respectively, 48 h after treatment by dipping method. By means of colorimetry the activities of some esterases treated with the alkaloids were studied. The results indicated that the alkaloids could inhibit activity of acetylcholinesterases (ACHE), the effectiveness of inhibiting AChE is: total alkaloids from the plant＞cytisine＞sophoraminesophoradine＞sophocarpine＞oxymatrine＞matrine＞aloperine. Cytisine and aloperine inhibit the activity of a-NA esterase, a-NA carboxylesterase and esterase isozyme as well.