拟细羽束梗孢发酵菌丝体中自由基清除活性成分分析

Analysis of radical scavenging active constituents in the mycelia of Isaria gracilioides

摘要:

用二苯基苦基苯肼(DPPH)自由基法, 首次对拟细羽束梗孢(Isaria gracilioides RCEF3 279)菌丝体的不同溶剂提取物进行了自由基清除活性的定性定量分析, 发现其甲醇提取物具有较强的清除自由基活性, 当菌丝浓度为10 g/L时, 其甲醇提取物的自由基清除率达到了92.4%±0.3%。DPPH自显影-薄层色谱分析结果显示有4个具自由基清除活性主要成分。高分辨液质联用和活性联合分析发现, 提取物中4个具自由基清除活性成分的可能分子式分别为C15H16NO3 (1)、C32H40N2O18 (2)、C30H55N5O5 (3)和C17H14N2O2 (4)。经天然产物数据库查询发现, 化合物3和4可能分别为Viscumamide和Dehydrocyclopepti, 这两个化合物在虫生真菌代谢产物中属首次发现。数据库查询没有发现与分子式C15H16NO3和C32H40N2O18匹配的结构式, 因此化合物1和2可能为新化合物。

Abstract:

A DPPH-microplate assay was employed for quantitative analysis of the free radical scavenging activity of the extracts extracted with different solvents from mycelia of Isaria gracilioides. The results showed that the methanol extract had the strongest free radical scavenging activity. At the concentration of 10 mg mycelium per milliliter methanol, the radical scavenging rate of the extract reached 92.4%±0.3%. The results of DPPH-TLC assays showed that the methanol extract contained four main free radical scavenging components. The combined LC-DAD-HRMS and DPPH assay revealed that the molecular formulas of the four free radical scavengers were possibly C15H16NO3 (1), C32H40N2O18 (2), C30H55N5O5 (3) and C17H14N2O2 (4). Natural products database query showed that compounds 3 and 4 were possibly viscumamide and dehydrocyclopeptin, respectively, and compounds 1 and 2 were novel molecules. Viscumamide and dehydrocyclopeptin were detected from entomogenous fungi for the first time.