Chemical constituents and pesticide efficacy of the fruit and root of solanum incanum L.

Solanum incanum L. is one of the Solanaceae family plants that grows in tropical African climates. The fruit and root sap extract of S. incanum is widely used as a pesticide, but little is known about pesticidal effectiveness and its pesticide-bioactive phytochemicals. The investigation included isolating and characterising secondary metabolites using a combination of the TLC, VC, CC, and HPTLC chromatography and spectroscopic techniques that included a combination of HRESIMS, 1D and 2D NMR, and FTIR and testing the efficacy of the isolated compounds against cabbage aphids using the aphid leaf dip assay. Phytochemical investigation of the fruit and root of S. incanum resulted in the isolation of nine compounds, which included two saponins 1 (a novel compound) and 4, phenyl ether 2, benzaldehyde 3, two alkaloids 5-6, two phenolics 7-8, and an enediol 9. Compounds 2 and 3 were reported for the first time from this plant. Compounds 6-9 showed different activity levels against the cabbage aphids with 6 exhibiting the highest efficacy exhibiting an LD50 value of 32.7 ± 6.10 µg·mL-1. The isolated compounds are potential targets for developing lead compounds in controlling cabbage aphids.