Detection of polyhydroxyalkaloids in Lonchocarpus extracts by GC-MS of acetylated derivatives

The methanol extracts of the roots of Lonchocarpus cultratus, L latifolius and L subglaucescens, species native to Brazil, were all active in the brine shrimp lethality test. Fractions rich in polyhydroxylated alkaloids were obtained from these extracts and, following acetylation, were analysed by GC-MS leading to the identification of acetylated derivatives of 2,5-trans-dihydroxymethyl-3,4-trans-dihydroxypyrrolidine (1), 1-deoxymannojirimycin, 1-deoxynojirimycin, fagomine and homonojirimycin. Only from L. subglaucescens could a compound with the constitution and relative configuration expected for the penta-acetate of 1 be isolated, and its molecular structure was determined for the first time through extensive spectral data analysis. Copyright (C) 2002 John Wiley Sons, Ltd.