Musidunin and musiduol, insect antifeedants from Croton jatrophoides.

Two novel limonoids, musidunin (1) and musiduol (2), were isolated from a methanol extract of Croton jatrophoides by bioassay-guided fractionation. Their structures were established by extensive NMR experiments. Interestingly, A,B-seco limonoid 1 contains a unique acetal annulation of A, A', and B' rings.

Insect antifeedants from Croton jatrophoides: structures of zumketol, zumsenin, and zumsenol.

Three new A-seco limonoids, zumketol (1), zumsenin (2), and zumsenol (3), were isolated from a methanol extract of Croton jatrophoides by bioassay-guided fractionation, and their structures were determined by NMR analysis. The alpha-ketol 1 may be biosynthesized via the intramolecular acyloin condensation of a dicarboxylate intermediate.

Insect antifeedants from tropical plants: structures of dumnin and dumsenin.

Two novel A-seco limonoids, dumnin and dumsenin, were isolated from the methanolic extract of Croton jatrophoides by bioassay-guided fractionation, and the structures were determined by nuclear magnetic resonance, circular dichroism, and mass spectrometry experiments. These compounds showed potent antifeedant activity (PC(50) View Article and Find Full Text PDF

Insect antifeedants from tropical plants II: structure of zumsin.

A novel A-seco limonoid was isolated from methanolic extract of Croton jatrophoides and designated as zumsin. This compound showed potent antifeedant activity against two lepidopteran larvae, pink bollworm, Pectinophora gossypiella (PC(50) = 1 microg/cm(2), PC(95) = 8 microg/cm(2)), and fall armyworm, Spodoptera frugiperda (PC(50) = 2 microg/cm(2), PC(95) = 16 microg/cm(2)). The structure of zumsin was determined as 1 using a variety of spectroscopic methods including nuclear magnetic resonance, mass spectrometry, and circular dichroism.