STRUCTURE AND BIOACTIVITIES OF A THIOSULFINATE DERIVED BY PREVENTING ONION LACHRYMATORY FACTOR SYNTHESIS

In normal onion (Allium cepa), trans-S-1-propenyl-L-cysteine sulfoxide (PRENCSO) is transformed via 1-propenesulfenic acid into propanethial S-oxide, a lachrymatory factor (LF), through successive reactions catalyzed by alliinase and lachrymatory factor synthase (LFS). A recent report showed that suppression of the LFS activity caused a dramatic increase in thiosulfinates previously reported as “zwiebelane isomers”. After purification by recycle-HPLC and subsequent analyses, we established the planar structure of the putative “zwiebelane isomers” as S-3,4-dimethyl-5-hydroxythiolane-2-yl 1-propenethiosulfinate, in which two of the three molecules of 1-propenesulfenic acid involved in the formation gave the thiolane backbone, and the third molecule gave the thiosulfinate structure.
Of at least three stereoisomers observed, one in (2’R,3’R,4’R,5’R)-configuration was collected as an isolated fraction, and the other isomers were collected as a combined fraction because spontaneous tautomerization prevented further purification.
Both fractions showed inhibitory activities against cyclooxygenase-1 (COX-1) and α-glucosidase in vitro.

VI International Symposium on Edible Alliaceae

M. Aoyagi, T. Kamoi, M. Kato, H. Sasako, N. Tsuge, S. Imai

Allium cepa, LFS, LF, 1-propenesulfenic acid, thiosulfinate, cepathiolane, zwiebelane, LFS suppressed onion, COX inhibition, α-glucosidase inhibition

https://doi.org/10.17660/ActaHortic.2012.969.29