Identification and antifeedant activities of limonoids from Azadirachta indica

Four new limonoids, azadiraindins A-D (1-4, resp.), together with seven known analogs, were isolated from the MeOH extract of Azadirachta indica. The structures of 1-4 were elucidated by NMR and MS spectroscopic analyses, and the relative configuration of 1 was determined by single-crystal X-ray crystallography. The compounds isolated in comparatively large amount were evaluated for their antifeedant activities against Plutella xylostella; the antifeedant rate of 10 was 90.6% and the corrected mortality of 8 was 79.2%.