Four novel insecticidal sesquiterpene esters from Celastrus angulatus

Four new insecticidal sesquiterpene polyol esters with a β-dihydroagarofuran sesquiterpene skeleton, celangulatin C (1), celangulatin D (2), celangulatin E (3), and celangulatin F (4), and five known compounds 5–9 were isolated from the low-polar toluene extracts of the root bark of Celastrus angulatus by bioassay-guided fractionation. Their chemical structures were elucidated mainly by analyses of MS and NMR spectral data. Celangulatin C, E and F showed LD50 against Mythimna separata were 280.4, 1656.4 and 210.5 µg mL−1, respectively.