EVALUATION OF ANTIOXIDANT AND LARVICIDAL ACTIVITIES OF SELECTED TAMARIX SPECIES AGAINST THE SOUTHERN HOUSE MOSQUITO "CULEX QUINQUEFASCIATUS (SAY)"

The present study was aimed to evaluate Tamarix baluchistanica (Qaiser), Tamarix androssowii (Bunge) and Tamarix mascatensis (Bunge) for scavenging of 2,2-diphenyl-1-picryl-hydrazyl (DPPH), 2, 2'-azino-bis-3-ethylbenzothiazoline-6- sulfonate (ABTS) free radicals and larvicidal potential against mosquito Culex quinquefasciatus; an important vector for lymphatic filariasis. The aerial parts of plants dried in shade, extracted with methanol and subsequently evaluated for antioxidant and larvicidal activities. The Crude extracts of T. baluchistanica, T. androssowii and T. mascatensis exhibited ABTS scavenging of 17%, 4.6% and 6% at concentration of 20 mu g/ml and 50%, 23% and 30% at concentration of 100 mu g/ml, respectively, similar results were observed for DPPH free radicals scavenging activity. The most active methanolic extract of T. baluchistanica was subjected to fractionation. Antioxidant bioassays revealed that ethyl acetate fraction was most potent among all the fractions, exhibited IC50 of 32.46 mu g/ml and IC90 of 91.32 mu g/ml against DPPH radicals. This was similar to the standard antioxidant, ascorbic acid which showed IC50 of 32.48 mu g/ml and IC90 of 86.73 mu g/ml. Antioxidant activity against ABTS demonstrated that among all the fractions, least IC50 of 37.94 mu g/ml and IC90 of 129.85 mu g/ml was also recorded for ethyl acetate fraction of T. baluchistanica extract, comparable to reference antioxidant, BHT having IC50 of 36.78 mu g/ml and IC90 of 113.07 mu g/ml. The crude extract of T. baluchistanica showed more larvicidal activity against the 3rd instar larvae of Cx. quinquefasciatus. The chloroform fractions showed lowest LC50 of 0.06 mg/ml, followed by n -hexane fraction having LC50 of 1.26 mg/ml, while lowest LC90 (2.12 mg/ml) was exhibited by n-hexane fraction, followed by chloroform fraction (7.94 mg/ml). The antioxidant and larvicidal activity of these species are reported for the first time. Further research is required to isolate and identify the active components of the plant extracts for effective implication in the control of the vector.