Abstract

PRELIMINARY PHYTOCHEMICAL SCREENING AND ACTIVITIES OF CITRULLUS COLOCYNTHIS (L.) SCHRAD. AS MOSQUITO LARVICIDES

Abdalla Abdelrahim Satti* and Amal Elsayed Edriss

Abstract

Citrullus colocynthis is a widespread wild cucurbit herb of multi traditional uses in Sudan. The current laboratory work was aimed to scrutinize the main phytochemical constituents of three extracts (water, ethanol and petroleum ether) prepared from leaves and fruits of C. colocynthis and to evaluate their biological activities against the 4th instar larvae of Anopheles arabiensis Patton, the main malaria vector in the country. The knockdown and residual effects of botanical treatments were evaluated in comparison with two standard insecticides. The phytochemical analysis revealed various compounds, dominated by; alkaloids, saponins and flavones in water extracts, alkaloids and triterpenes in ethanol extracts and triterpenes and sterols in petroleum ether extracts. Generally, the highest chemical groups were triterpenes, flavones and alkaloids; then followed by sterols and amino acids. Fruits seemed to be richer in active compounds than the leaves. Consequently, petroleum ether extracts showed better mortality results than water and ethanol extracts, but all showed significant effects. The fruits were more potent than the leaves, and in most cases the activities increased in relation to concentration and exposure time. In conclusion, fruits petroleum ether extract (0.5%) was the best botanical treatment which showed comparable significant effect (84.2 ± 6.7% mortality) with those of the two insecticides (90.0 ± 0.0%) at 24 h post exposure. This treatment also manifested the best significant residual actions up to three weeks, but ranked next in order to synthetic insecticides. Such promising product needs to be investigated in advanced research.

Keywords: Citrullus colocynthis; Anopheles arabiensis; phytochemical; mortality; residual.