Abstract: Objective To determine the contributions of main chemical compositions of extracts of Eucalyptus camaldulensis represented by GC/MS elute peaks to the molluscicidal activities，and explore a shortcut of looking for the effective components from natural products. Methods E. camaldulensis leaves were collected consecutively in 12 months at the same place，extracted with dichloromethane，analyzed by GC/MS，and their LC50 （s）of molluscicidal activities were tested according to the method rec? ommended by WHO. The correlation of the main components in 12 extracts and their molluscicidal activities were analyzed by the grey relative correlation analysis model with software GTMS 3.0. Result All the dichloromethane extracts of eucalyptus leaves showed excellent molluscicidal activities with the highest LC50 of 0.257mg/L and 0.242mg/L for the samples in June and July and the lowest LC50 of 6.802 mg/L and 5.406 mg/L in December and January respectively. The structures of 16 main chemical compo? nents were elucidated by GC/MS and NIST Mass Spectral Library，most of which were monoterpenes and sesquiterpenoids. The gray correlation coefficients with activity were all over 0.5，the first five over 0.9 were 4， 4， 8?Trimethyltricyclo ［6.3.1.0 （1， 5）］ do? decane?2， 9?diol， （?） ?Spathulenol，a structural isomer of（?） ?Spathulenol，Eucalyptol and Ledol. Conclusion The most main in? gredients in the dichloromethane extracts of E. camaldulensis leaves show good correlations with the molluscicidal activity，which suggests that the molluscicidal role is synergistically played by the multiple components together.

Key words: Eucalyptus camaldulensis；Oncomelania hupensis；GC/MS；Gray correlation analysis；Spectrum?effect correlation；Molluscicidal activity

摘要： 目的 目的 确定赤桉叶中主要GC/MS峰所代表的化学成分以及其对杀螺作用的贡献， 探索一条从天然产物中寻找有 效成分的快捷途径。方法 方法 在同一地点连续采集12个月的赤桉树叶， 并采用二氯甲烷提取； 利用GC/MS技术分析其化学 成分； 采用室内浸杀法进行杀螺药效实验并计算LC50； 利用灰色系统理论建模软件对12个月赤桉叶提取物的主要成分及 其相应提取物的杀螺活性作灰色关联分析。结果 结果 赤桉树叶的二氯甲烷提取物均表现出较好的杀螺活性， 尤以6月和7 月采集的样品杀螺作用最强， 其LC50分别为0.257 mg/L和0.242 mg/L， 而1月和12月的样品杀螺作用最弱， LC50分别为 6.802 mg/L和5.406 mg/L。GC/MS分析鉴定了16个主要化学成分， 多为单萜及倍半萜类化合物； 与杀螺活性的灰色相对关 联度均 > 0.5，其中5个成分的灰色关联度 > 0.9， 分别为4， 4， 8?三甲基 ［6.3.1.0 （1， 5）］ 三环十二烷?2， 9?二醇、 （?） ?桉油烯醇、 （?） ?桉油烯醇的同分异构体或类似物、 1， 8?桉叶油素、 喇叭茶醇。结论 结论 赤桉叶二氯甲烷提取物中多个成分与杀螺活性均 表现出了较好的关联度， 提示其杀灭钉螺作用可能是多种化学成分共同作用的结果。

关键词: 赤桉； 钉螺； GC/MS； 灰色关联分析； 谱?效关系； 杀螺作用