New quinolizidine alkaloid and insecticidal activity of Sophora secundiflora and Sophora tomentosa against Culex pipiens (Diptera: Culicidae)

Abstract

Phytochemical investigation of Sophora secundiflora alkaloid fraction led to isolation of one new quinolizidine alkaloid (1) 13-methoxyanagyrine together with six known ones (2-7). The insecticidal activity of 70% methanol extract of leaves of S. secundiflora, S. tomentosa and the isolated alkaloids were assessed against 3rd instar larvae of Culex pipiens (Diptera: Culicidae) using different concentrations and mortality rate was recorded. Sophora tomentosa extract showed highest mortality rate with median lethal concentration LC50 3.11 ppm after 24 h and 0.66 ppm after 48 h and anagyrine (6) exhibited remarkably insecticidal activity with LC50 value of 3.42 ppm after 24 h of exposure. Additionally, cytotoxic activity of alkaloid fraction of S. secundiflora, S. tomentosa and isolated alkaloids was also studied using crystal violet assay against MCF-7 and HEPG-2 cell lines. Anagyrine (6) exhibited IC50 values of 27.3 ± 0.7 and 30.2 ± 0.9 µg/mL against MCF-7 and HEPG-2 cancer cells, respectively.