Alkaloidal constituents of Crinum asiaticum L., toxicology and in silico studies against some piercing-sucking pests

Abstract Many important crops around the world have been severely damaged by piercing-sucking pests. These pests can be managed with botanical pesticides. A major alkaloid, hippeastrine- N -oxide 3 , was isolated from the Crinum asiaticum alkaloid fraction. In addition, four known compounds, 11-hydroxyvittatine- N -oxide 1 , lycoramine- N -oxide 2 , lycorine 4 , and vittatine 5 , were identified by LC-MS/MS. 1 H NMR and ESI-MS spectroscopy were used to identify the structure of the isolated compound. Pesticidal activity of the alkaloid fraction and hippeastrine N -oxide was tested against four piercing-sucking pests along with azadirachtin as a positive control under laboratory conditions. Hippeastrine- N -oxide showed high toxicity against four pests, especially Aphis craccivora , compared to the control, with LC 50 values of 16.00 and 26.90 mg/L, respectively. The LC 50 value of hippeastrine- N -oxide was used to evaluate the biochemical characteristics of six Aphis craccivora enzymes. Molecular docking and fingerprint analysis of the lead compound revealed strong binding interactions with key amino acid residues in the target enzymes, further validating the experimental findings. These computational results make it possible to understand the mechanism of action observed in the laboratory assays. These findings indicate that the C. asiaticum alkaloid fraction, and hippeastrine N ‑oxide in particular, exhibit insecticidal activity against the piercing‑sucking pests tested under laboratory conditions, supporting further evaluation of their potential as botanical pest-control agents.