Bioefficacy of essential oil from Polygonum hydropiper L. against mosquitoes, Anopheles stephensi and Culex quinquefasciatus.

The biological activity of essential oil extracted from the leaves of Polygonum hydropiper and a compound, confertifolin, isolated from this plant was bioassayed against larva of mosquitoes, Anopheles stephensi and Culex quinquefasciatus. The essential oil showed the LC50 values of 189 and 243ppm; 217 and 242ppm, confertifolin (6,6,9a-trimethyl-4,5,5a,6,7,8,9,9a-octahydronaphtho[1,2-c]furan-3(1H)-one) showed the LC50 values of 2.40 and 3.09ppm; 4.07 and 4.18ppm against the second and fourth instar larvae of An. stephensi and Cx. quinquefasciatus, respectively. At 10ppm confertifolin showed ovicidal activity of 100, 98.6 and 86.4% against An. stephensi and 100, 100 and 75.2% against Cx. quinquefasciatus on 0-6, 6-12 and 12-18h old eggs; the repellent activity persisted for 314.6 and 319.0min; oviposition deterrent activity was 97.2 and 99% and adulticidal activity was 100 and 100% against An. stephensi and Cx. quinquefasciatus, respectively. The results were statistically significant. Confertifolin could be considered for use in the control of human vector mosquitoes.