骆驼蓬提取物对松材线虫的生物活性及生理效应

Bioactivities and Physiological Effects of Extracts of Peganum harmala Against Bursaphelenchus xylophilus

为寻找创制新型生物合理杀线虫剂提供活性模板化合物和理论基础,首次报道广泛分布于中国西北地区的荒漠抗逆植物骆驼蓬对松材线虫的生物活性及生理效应。松枝水培试验结果表明,骆驼蓬种子正丁醇萃取物250μg·ml-1处理后,松枝蒸腾强度、流脂量级别和病情指数均与清水对照差异不显著,对松材线虫病害的控制效果明显优于石油醚萃取物、氯仿萃取物和水萃取物。从正丁醇萃取物中分离获得骆驼蓬总碱、骆驼蓬碱、去氢骆驼蓬碱和馏分A1～A8。毒力测定表明,骆驼蓬碱、馏分A1和A6是骆驼蓬杀线虫的主要活性成分,处理后48h,对松材线虫(混合虫龄)LC50分别为135.74、160.40和86.02μg·ml-1。正丁醇萃取物、骆驼蓬总碱、骆驼蓬碱、去氢骆驼蓬碱、馏分A1和A6均能显著抑制乙酰胆碱酯酶和酸性磷酸酯酶活性,但对碱性磷酸酯酶活性无显著影响,对α-和β-乙酸萘酯羧酸酯酶活性有不同程度的抑制作用,以100μg·ml-1处理松材线虫后6h,乙酰胆碱酯酶比活力抑制率为50.15%～73.14%,对酸性磷酸酯酶活性的抑制率为38.56%～48.37%。抑制乙酰胆碱酯酶活性可能是骆驼蓬提取物主要杀线虫机理之一。

Peganum harmala L.is a resistant plant distributed in the desert area of China. The rising intensity of moisture, level of resinosis and index of disease of pine infected by mixed instar of Bursaphelenchus xylophilus were not significantly different from CK when pine branch were treated with 250 μg·ml^-1 of n-butanol extract of P.harmala in water-potted test, which indicated n-butanol extract of P. harmala shows control effects superior to petroleum ether, chloroform and water extract against B.xylophilus. The total alkaloid extract, harmaline, harmine and 8 fractions named A1-A8 were obtained from n-butanol extract. Result of these fractions＇ nematocidal toxicity test showed that harmaline, fraction A1 and A6 would be the main nematocidal components of P.harmala, their values of LC50 were 135.74,160.40 and 86.02 μg·ml^-1 after 48 h against mixed instar B.xylophilus, respectively. The n-butanol extract, total alkaloid, harmaline, harmine, fraction A1 and A6 all could not significantly inhibited the activities of aldaline phoisphatase, but AChE and acid phosphatase in vivo. After 6 h when mixed instar of B.xylophilus were treated at the concentration of 100 μg·ml^-1, the activities of AChE and acid phosphatase were inhibited by 50.15%-73.14% and 38.56%-48.37%, respectively. The inhibition rate of α-carboxylesterase activity were 39.78%, 33.80%, 34.85% and 54.22% after 12 h treated with total alkaloid extract, harmaline, harrnine and fraction A1 at concentration of 100μg·ml^-1 . However, n-butanol extract, harmine and fraction A1 significantly suppressed the activity of β-carboxylesterase than other extracts, the inhibition rate of activity got 42.79%, 33.66% and 30.02%, respectively after 12 h treated at the same concentration of 100μg·ml^-1 . Based on these experimental results, it is inferred that one of the nematocidal mode of action may inhibit the activity of AChE for P.harmala extract. More researches are needed on nematocidal components of P.harmala to search the main active compounds and develop some new kinds of biorational nematocide.