S-allylcysteine inhibits free radical production, lipid peroxidation and neuronal damage in rat brain ischemia

The efficacy of S-allylcysteine (SAC) as a free radical scavenger was studied using rat brain ischemia models, In a middle cerebral artery occlusion model, preischemic administration of SAC had the following effects: it improved motor performance and memory impairment and reduced water content and the infarct size. In a transient global ischemia model, the time course of free radical (alkoxyl radical) formation as studied by electron paramagnetic resonance (EPR) spectroscopy and alpha -phenyl-N-tert-butylnitrone (PBN) was biphasic; the first peak occurred at 5 min and the second at 20 min after reperfusion. Although SAC did not attenuate the first peak, it did affect the second peak, which is related to lipid peroxidation. The lipid peroxidation as estimated by thiobarbituric acid reactive substances (TBARS) increased significantly at 20 min after reperfusion, SAC decreased TBARS to the levels found without ischemia. These results suggest that SAC could have beneficial effects in brain ischemia and that the major protective mechanism may be the inhibition of free radical-mediated lipid peroxidation.