The amino acid precursors and odor formation in society garlic (Tulbaghia violacea Harv.).
Identification and isolation of (R(S)R(C))-S-(methylthiomethyl)cysteine-4-oxide from rhizomes of Tulbaghia violacea Harv. is reported. The structure and absolute configuration of the amino acid have been determined by NMR, MALDI-HRMS, IR, and CD spectroscopy. Its content varied in different parts of the plant (rhizomes, leaves, and stems) between 0.12 and 0.24 mg g(-1) fr. wt, being almost equal in the stems and rhizomes. In addition, S-methyl- and S-ethylcysteine derivatives have been detected in minute amounts (<3 microg g(-1) fr. wt) in all parts of the plant. The enzymatic cleavage of the amino acid and subsequent odor formation are discussed. 2,4,5,7-Tetrathiaoctane-4-oxide, the primary breakdown product, has been detected and isolated for the first time.
Kubec
Roman
R
Department of Chemistry, State University of New York at Albany, Albany, NY 12222, USA.
Velísek
Jan
J
Musah
Rabi A
RA
D000490:Allium / Q000737:chemistry / Q000378:metabolism*; D000596:Amino Acids / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D009812:Odorants / Q000032:analysis*; D010087:Oxides / Q000378:metabolism; D018514:Plant Structures / Q000737:chemistry / Q000378:metabolism; D013057:Spectrum Analysis
D000596:Amino Acids; D010087:Oxides