A Study On The Synthesis And Molluscicldal Activity Of Gingkolic Acid Analogs

Schistosomiasis is a serious public health disease that the government has to face. The epidemic situation has been rising rapidly in recent years. In our country, Oncomelania hupensis is the only host of schistosome. So, to kill it is a useful way to control the spread of schistosomiasis. Niclosamide, the only specified mollusicicide by WHO, has been widely used all over the world. Despite all this, because of its high toxicity and cost, a highly effective, safe and cheap medicine is needed. Plants which have effect on Oncomelania hupensis are to be sought and tested. The outstanding effect on killing Oncomelania hupensis of the sarcotestas of Ginkgo biloba L has attracted more and more attentions.Ginkgolic acid is the main constituent of the sarcotestas of Ginkgo biloba L, which also exists in fruits and leaves. And the further research proves its effects on Oncomelania hupensis. It has the potential to become an effective, safe and cheap mollusicicide. After studying the structure of ginkgolic acid, under the guidance of drug design principles, we decide to rebuild the structure of ginkgolic acid, including changing the position and length of the alkyl chain of salicylic acids, doing some modification of the carboxylic group and hydroxyl group, to study the structure-activity relationship of ginkgolic acid and its killing Oncomelania hupensis effects. Finally, 6 different alkyl salicylic acids were synthesized and tested on the effects on killing Oncomelania hupensis.All of the ginkgolic acid analogs show good mollusicicidal activities. Moreover, the data reveals that the hydroxyl group and carboxyl group are necessary for its activity. Besides, the length of the alkyl chain related to its mollusicicidal activity and the inhibitory rate of climbing-upward. The shorter chain analog shows higher activity.This study reveals some SAR relationship between ginkgolic acid analogs and its mollusicicidal activity. The length of the alkyl chain is one of the key points to improve the activity of ginkgolic acid and should be studied further.