Cysteine sulfoxide derivatives in Petiveria alliacea

Two diastereomers of S-benzyl-L-cysteine sulfoxide have been isolated from fresh roots of Petiveria alliacea. Their structures and absolute configurat ions have been determined by NMR, MALDI-HRMS, IR and CD spectroscopy and co nfirmed by comparison with authentic compounds. Both the R-S and S-S diaste reomers of the sulfoxide are present in all parts of the plant (root, stem, and leaves) with the latter diastereomer being predominant. Their total co ntent greatly varied in different parts of the plant between 0.07 and 2.97 mg g(-1) fr. wt, being by far the highest in the root. S-Benzylcysteine has also been detected in trace amounts (< 10 mug g(-1) fr. wt) in all parts o f the plant. This represents the first report of the presence of S-benzylcy steine derivatives in nature. (C) 2001 Elsevier Science Ltd. All rights res erved.