Abstract

There is an urgent need to replace highly polluting pesticides with environmentally friendly green pesticides of high efficiency and low toxicity, because of the growing concern for quality and safety of agricultural products. To discover new pesticides with diverse chemical structures from natural products, a series of rhein derivatives 3a-9b were designed, synthesized, and evaluated for their antifungal activity and insecticidal activity. The bioassay showed that some compounds exhibited moderate antifungal activity against Rhizoctonia solani, but lower activity against the other five pathogens. Surprisingly, most compounds displayed potent insecticidal activity against Spodoptera litura and Tetranychus cinnabarinus at a concentration of 2 μmol/mL. In particular, compounds 3a, 5a and 3 b exhibited potent insecticidal activities against S. litura at 72 h, with mortality rates of 100%, 100% and 92.1%, respectively, which were equivalent to that of the insecticide fipronil (100%). Their structure-activity relationships were also discussed. The findings of this experiment provide helpful research ideas for the development of these rhein derivatives as novel natural product-based pesticides in crop protection.

摘要

农产品质量安全日益受到关注，迫切需要用高效、低毒、环保的绿色农药替代高污染农药。为了从天然产物中发现具有不同化学结构的新农药，设计、合成了一系列大黄酸衍生物3a-9b，并评估了它们的抗真菌活性和杀虫活性。生物测定表明，一些化合物对立枯丝核菌表现出中等的抗真菌活性，但对其他五种病原体的活性较低。令人惊讶的是，大多数化合物对斜纹夜蛾和红叶叶螨显示出有效的杀虫活性浓度为 2 μmol/mL。特别是化合物3a、5a和3b在72小时内对斜纹夜蛾具有强效杀虫活性，死亡率分别为100%、100%和92.1%，与杀虫剂氟虫腈(100%)相当. 还讨论了它们的构效关系。本实验的结果为开发这些大黄酸衍生物作为作物保护中的新型天然产物农药提供了有益的研究思路。