ROS are also involved in the pathogenesis of gastric malignancies (32). To date, the correlation between administration of ABGE and its effect on the status of SOD and GSH-Px have yet to be fully investigated. In this study, the activities of SOD and GSH-Px were significantly increased by the administration of ABGE in an animal model. Considering that ROS are inversely correlated to the induction of apoptosis (as mentioned above), these results offer a plausible explanation of the antioxidative and antiproliferative effects of ABGE. In the context of the previous literature, administration of ABGE may exert its antioxidative role directly and indirectly. During the aging process of ABGE, compounds in fresh garlic are converted into stable and water-soluble OSCs such as S-allyl cysteine (SAC) and S-allylmercapto-L-cysteine (SAMC). It has been reported that SAC and SAMC possess high radical scavenging activity, which directly removes ROS (33,34). In addition to this direct effect, ABGE also increases the activity of antioxidant enzymes, so that excessive ROS is indirectly cleared (35). Consistent with our study, enhancement of the circulating levels of SOD and GSH-Px were observed following administration of garlic extract in the circulation of tumor-bearing animals.