Pharmacological action of integument extracts of red palm weevil, Rhynchophorus ferrugineus on albino mice

Extracts were prepared from the tergum and sternum of male and female red palm weevil, Rhynchophorus ferrugineus, using acetone, chloroform and diethyl ether. Pharmacological actions were examined in mice. All of the extracts showed certain behavioral actions that included central nervous system inhibition and stimulation with no effects on pain perception or temperature regulation.Two of the extracts labeled numbers 1 and 2 (acetone and chloroform extracts of the female insect tergum) were found to exhibit cardiac depressant effects. Extract No.1 induced time- dependent bradycardia ( up to 40% inhibition of heart rate) that was significantly antagonized by atropine. It also enhanced calcium chloride- induced bradycardia in mice. Insect extract No.2 also exhibited cardiac depressant effect (up to 37.5%bradycardia) that was not affected by atropine.The extract significantly blocked calcium chloride-induced bradycardia. Extracts No.1 and 2 seemed to contain muscarinic and calcium channel bloking components, respectively. Isolation of these components may pave the way for discovery of potential cardiac depressants that may be useful in treatment of certain cardiac dysrrhythmias.