番荔枝内酯化合物布拉它辛对斜纹夜蛾的杀虫活性及对SL细胞的致凋亡作用

为了明确番荔枝内酯化合物布拉它辛的杀虫活性和探索杀虫作用机理，本研究采用浸叶法测定该化合物对斜纹夜蛾Spodoptera litura幼虫的生物活性，采用MTT检测法和流式细胞术，研究该化合物对斜纹夜蛾离体培养卵巢细胞（SL细胞）的细胞毒力和致细胞凋亡作用，以及对SL细胞线粒体膜电位的影响。结果表明: 布拉它辛不仅对斜纹夜蛾幼虫具有良好的拒食活性，处理后24 h，对2龄和3龄幼虫的AFC₅₀值分别为60.25 μg/mL和86.73 μg/mL，还对幼虫生长有良好的抑制作用。布拉它辛处理SL细胞后24 h和48 h，IC50值分别为22.32 μg/mL和10.03 μg/mL。流式细胞仪检测结果表明，布拉它辛对SL细胞具有明显的致凋亡作用，可导致SL细胞线粒体膜电位显著下降。本研究表明布拉它辛对斜纹夜蛾幼虫具有良好的拒食活性与生长抑制作用, 并且该化合物能明显抑制SL细胞的增殖，诱导细胞凋亡，降低线粒体膜电位。因此，布拉他辛具有广阔的研究应用前景。

Insecticidal activity of bullatacin against Spodoptera litura(Lepidoptera :Noctuidae)and the induced apoptosis to SL cells

In order to ascertain the insecticidal activity and probe into the insecticidal mechanism about bullatacin, we studied the biological activity against Spodoptera litura larvae by bullatacin with leaf feeding method, and observed the cytotoxicity to S. litura ovary cells （SL cells） using MTT method. Meanwhile, we detected cell apoptosis and the change of mitochondrial membrane potential of SL cells by flow cytometer. The results indicated that bullatacin had the antifeedant activity against the 2nd and 3rd instar larvae of S. litura. The AFC₅₀ values were 60.25 μg/mL and 86.73 μg/mL, respectively. This compound also had strong inhibitive activity on the growth of S. litura larvae. The IC₅₀ values on SL cells at 24 and 48 h post treatment were 22.32 μg/mL and 10.03 μg/mL, respectively. Observations by flow cytometer showed that bullatacin induced apoptosis and the decrease of mitochondrial membrane potential in SL cells. The results suggest that bullatacin possesses the antifeedant activity and has strong inhibitive activity on the growth of S. litura larvae. In addition, it can inhibit the proliferation, induce the cell apoptosis and decrease the mitochondrial membrane potential in SL cells. Therefore, bullatacin has a good research and application prospect.