Effect of active molluscicidal component of spices on different enzyme activities and biogenic amine levels in the nervous tissue of Lymnaea acuminata

In vivo exposure of Lymnaea acuminata to thymol and [6]-gingerol (active mo lluscicidal components of Trachyspermum ammi and Zingiber officinale, respe ctively) indicates that they significantly alter acetylcholinesterase, lact ic dehydrogenase, succinic dehydrogenase and cyto-oxidase activity in the n ervous tissue of snails. In vitro exposure showed that, except for acetylch olinesterase and lactic dehydrogenase, no significant changes were observed in cyto-oxidase and succinic dehydrogenase activity in the nervous tissue of L. acuminata. Sublethal exposure to thymol and [6]-gingerol reduced the levels of 5-hydroxytryptamine (5-HT) and dopamine (DA) in the nervous tissu e of L. acuminata. There was, however, no significant change in the level o f 5-hydroxy indol acetic acid (5-HIAA). Thymol and [6]-gingerol thus affect s all the known neurotransmission mechanisms in the snail either separately or through a complex interaction between the different neurotransmitters, This may account for their toxicity to snails. Copyright (C) 1999 John Wile y & Sons, Ltd.