印楝油氯仿提取物杀螨活性成分的分离纯化及其生物学活性

Purification and biological activities of an acaricidal active compound from chloroform extract of neem oil

将印楝油氯仿提取物经硅胶柱层析和丙酮重结晶进行生物活性跟踪分离纯化,并运用互补重对数模型(CCL模型)分析活性化合物的离体生物活性,求出半数致死浓度(LC50)和半数致死时间(LT50)。结果显示,从印楝油氯仿提取物中分离出一种白色雪花状丙酮结晶物,熔点为60～61℃,经结构鉴定为18-碳酸-3,4-呋喃二酯,其对兔疥螨幼虫的杀螨活性呈时间浓度依赖性,24h的LC50和LC90分别为0.0818和9.8424g/L,7.500g/L时的LT50和LT90分别为15.3324h和24.6784h。这表明印楝油氯仿提取物的杀螨活性成分主要为酯类物质,对兔疥螨具有较强的杀螨活性。

Bioassay-directed fractionation of the chloroform extract of the neem oil, was conducted by the isolation with silica gel column chromatography,and the active component was re-crystallized with acetone. A complementary log-log model was used to analyze biological activities of the active compounds in vitro. The median lethal time （LT50） and the median lethal concentration （LC50） were accumulated by CCL model. The results showed that a white snowflake crystal with a melting point of 60-61 C was isolated from the chloroform extract of the neem oil. Its structure was identified as octadecanoic acid-3,4-furanodiyl ester. The crystallization revealed the time and dosedependent relationship as acaricide against Sarcoptes .wabiei vat. cuniculi larvae. The LC50 and LC50 values were 0. 081 8,9. 842 4 g/L after 24 h, respectively. The LT50 and LT50 values of 7. 500 g/L crystallization were 15. 332 4 h and 24. 678 4 h, respectively. These results suggest that the acaricidal activity components of the chloroform extract of the neem oil are ester derivatives that have the acaricidal effect against Sarcoptes scabiei var. cuniculi.