Larvicidal activity of lignans from Phryma leptostachya L. against Culex pipiens pallens

Abstract

The larvicidal activity of crude petroleum ether, ethyl acetate, and methanol extracts of the whole plants of Phryma leptostachya L. was assayed for its toxicity against the early fourth instar larvae of Culex pipiens pallens. The larval mortality was observed after 24 h of exposure. Among three solvent extracts from Phyrma leptostachya L., the petroleum ether extract exhibited the best larvicidal activity. The corresponding LC₅₀ values of petroleum ether, ethyl acetate, and methanol extracts were 3.23, 5.23, and 61.86 ppm against the early fourth instar larvae of Culex pipiens pallens. The petroleum ether extract was successively subjected to column chromatography and preparative high performance liquid chromatography, and yielded the three lignans, phrymarolin-I, haedoxane A, and haedoxane E, which were isolated and identified as new mosquito larvicidal compounds. Phrymarolin-I, haedoxane A, and haedoxane E showed high larvicidal activity, for which the lethal doses LC₅₀ were estimated at 1.21, 0.025, and 0.15 ppm against the early fourth instar larvae of Culex pipiens pallens, respectively. The structures were elucidated by analyses of IR, UV, MS, and NMR spectral data. This is the first report on the mosquito larvicidal activity of the three compounds, phrymarolin-I, haedoxane A, and haedoxane E from Phyrma leptostachya L.

Efficacy of bioactive compounds from Curcuma longa L. against mosquito larvae

“…The extracts of Amyris balsamifera , Daucus carota and Pogostemon cablin showed 100% larvicidal activities against C. pipiens pallens at 100 ppm (Park & Park, ). The LC 50 of the methanolic extract of Phryma leptostachya L. was 61.86 ppm (Xiao, Hu, Shi, Wei, & Wu, ). While Ali, Wang, and Khan () reported the LC 50 values of C. longa rhizome extract against A. aegypti and Anopheles quadrimaculatus were 38.2 and 7.5 ppm, respectively, Madhu et al.…”

Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Culex quinquefasciatus Say (Diptera: Culicidae)

“…The corresponding LC 50 values of petroleum ether, ethyl acetate, and methanol extracts were 3.23, 5.23, and 61.86 mg/L against the early fourth instar larvae of Cx. pipiens pallens [23] . Thanigaivel et al reported that the larvicidal activity of methanolic fractions from Adhatoda vasica leaf extracts were investigated against the Bancroftian filariasis vector Cx.…”

Synthesis and Larvicidal Activity against Culex pipiens pallens of New Triazole Derivatives of Phrymarolin from Phryma leptostachya L.

“…As part of an ongoing effort to identify potential pesticide molecules derived from natural products it was shown that lignans including Haedoxane A, Phrymarolin B and Phrymarolins I are the main active components of P. leptostachya L. (Figure 1) [8–10]. In our previous study [11–13], we found that some of the C-11 ether derivatives and dehydroxy Phrymarolin showed much higher activity than Phrymarolins I. We were interested in making analogues with a triazole substituent linked to C-11, since triazole is a common group to a well-known class of pesticides.…”