Hitherto unobserved inhibition of insect chitinase enzyme by natural terpene
Agatha Christy and K Jayaprakash
It is more benefit to develop an antimosquito agent to attack the larval development rather than using chemicals directly influenzing chitin metabolism. Gossypol a natural toxic terpene has shown antimicrobial activity. The LC50 dose of 195.4 ppm terpenoid aldehyde exposure for 48 hr among third stage larva of Anopheles stephensi has exhibited a block on the synthesis of ecdysone by interfering neuro transmitting acetylcholine in our earlier observation. In order to corroborate the above concept and the developmental disorder due to terpene, the terpene exposed experimental mosquito larval heads are homogenized and injected in to the nymph of Periplanata Americana. The hameolymph samples have shown significantly reduced chitinase enzyme activity while comparing the corresponding values of cockroach. This would suggested the impairment of chitin metabolism through the inhibition of ecdysone hormonal regulation by the terpene compound. Further the injected nymphs have prolonged larval period, restriction on the number of moulting and never attain adult characters. The above results are discussed with relation to antimosquito principle.