Bioassay-guided fractionation of an extract obtained from roots of Aglaia duperreana led to the isolation of 17 1H-cyclopenta[b]benzofurans of the rocaglamide type. Of the compounds isolated, four rocaglamide derivatives (2, 6, 11, and 16) were obtained as new natural products, and their structure elucidation was conducted by spectral methods. For bioassay-guided fractionation and determination of LC50 and EC50 values, neonate larvae of Spodoptera littoralis were employed. The results of chronic feeding assays have shown new aspects of the structure−activity relationship of rocaglamide derivatives. The substitution of a hydroxyl group at C-8b by a methoxyl substituent leads to a loss of insecticidal activity in a manner not previously documented in this compound class.

A phytochemical analysis of the leaves of Aglaia dasyclada collected in Yunnan Province (People's Republic of China) yielded five cyclopentabenzofurans (1-5) of the rocaglamide family that are common secondary metabolites of Aglaia species as well as four biogenetically related compounds of the aglain (7), aglaforbesin (8) and forbaglin (9, 10) types. In addition, the cinnamic acid amide dasyclamide (6), which is a putative biogenetic precursor of these compounds (7-10), was isolated. The structures of the new compounds (6-10) were assigned unambiguously from the combined use of 1D and 2D NMR spectroscopy and mass spectrometry.

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