Adult emergence inhibition and adulticidal activities of medicinal plant extracts against Anopheles stephensi Liston

Abstract

To determine the adult emergence inhibition (El) and adulticidal activities of hexane, chloroform, ethyl acetate, and acetone leaves extracts of Anisomeles malabarica (A. malabarica), Euphorbia hirta (E. hirta), Ocimum basilicum (0. basilicum), Ricinus communis (R. communis), Solanum trilobatum (S. trilobatum), Tridax procumbens (T. procumbens) and seeds of Gloriosa superba (G. superba) against Anopheles stephensi (An. stephensi). The El and adulticidal trials were carried out according to World Health Organization (WHO) procedures with slight modifications. The extracts were diluted in dimethyl sulphoxide in order to prepare a serial dilution of test dosages (15.625, 31.25, 62.5, 125, 250, 500 and 1 000 jU g/mL). Five duplicate trials were carried out for every sample concentration, and for each trial a negative control was included and the mortality was determined after 24 h of exposure. The highest El activity was found in ethyl acetate extracts of A. malabarica, chloroform extracts of 0. basilicum, S. trilobatum, acetone of extract of R. communis, T. procumbens, and seed extract of G. superba with EI50 values 143.12, 119.82, 157.87, 139.39, 111.19, and 134.85 fig/mL, and the effective adulticidal activity was observed in chloroform, acetone extracts of G. superba, T. procumbens, R. communis, S.trilobatum and ethyl acetate extract of 0. basilicum with LD50 values 120.17, 108.77, 127.22, 163.11, 118.27, and 93.02 l-i g/mL, respectively. Chi-square value was significant atP<0.05 level. These results should encourage further efforts to investigate the compounds that might possess good El and adulticidal properties when isolated in pure form.