Influence of Oxygen-Containing Sulfur Flavor Molecules on the Stability of ß-Carotene under UVA Irradiation.

The influence of 11 kinds of oxygen-containing sulfur flavor molecules was examined on ß-carotene stability under UVA irradiation in ethanol system. Both the effects of sulfides on dynamic degradation of ß-carotene and the relation between structure and effect were investigated. The oxidation products of ß-carotene accelerated by sulfides under UVA irradiation were also identified. The results indicated that the disulfides had more obvious accelerative effects on the photodegradation of ß-carotene than mono sulfides. The degradation of ß-carotene after methyl (2-methyl-3-furyl) disulfide (MMFDS), methyl furfuryl disulfide (MFDS) and bis(2-methyl-3-furyl) disulfide (BMFDS) exposure followed first-order kinetics. Furan-containing sulfides such as MMFDS and BMFDS showed more pronounced accelerative effects than their corresponding isomers. The oxidation products were identified as 13-cis-ß-carotene, 9,13-di-cis-ß-carotene and all-trans-5,6-epoxy-ß-carotene. These results suggest that both the sulfur atom numbers and the furan group in oxygen-containing sulfides play a critical role in the photooxidation of ß-carotene.

Oxidative stress-mediated antiproliferative effects of furan-containing sulfur flavors in human leukemia Jurkat cells.

Antiproliferative effects of 15 sulfides were investigated in human leukemia Jurkat cells. Treatment with 5-50 µM of nine monosulfides and two linear disulfides did not induce DNA fragmentation. Whereas, furan-containing sulfur flavors including methyl 2-methyl-3-furyl disulfide (MMFDS), bis (2-methyl-3-furyl) disulfide (BMFDS), methyl furfuryl disulfide (MFDS) and difurfuryl disulfide (DFDS) induced DNA fragmentation to a varying extent in Jurkat cells. The cell viability-reduction effect of these sulfur flavors was in the following order: DFDS>BMFDS>MMFDS>>MFDS based on the IC50 values. MMFDS and BMFDS, but not DFDS, significantly increased the intracellular ROS level by 1.90- and 3.02-fold, respectively. Addition of N-acetylcysteine (NAC) or glutathione (GSH) partially suppressed induction of DNA fragmentation, apoptosis and caspase-3 activation by MMFDS and BMFDS. These results suggest that the furan-containing disulfides have a strong antiproliferative effect, and the oxidative stress and subsequent caspase-3 activation are involved in antiproliferative effect induced by MMFDS and BMFDS in Jurkat cells.