Aspartame (a widely used artificial sweetener) and oxidative stress in the rat cerebral cortex

Aspartame (L-aspartyl-L-phenylalanine methyl ester, ASP) is one of the most widely used artificial sweeteners. Many concerns have been raised about the side effects of ASP consumption and its safety since different studies that investigated the effects of ASP revealed controversial results. The aim of the present study is to investigate whether the daily oral administration of ASP (40 mg/kg) for 2, 4 and 6 weeks induce oxidative stress in the rat cerebral cortex. Lipid peroxidation (LPO), glutathione reduced (GSH) and nitric oxide (NO) levels as well as the activities of superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) enzymes were determined. A significant decrease in LPO levels was obtained after 2 weeks of ASP administration and was followed by a significant increase after 4 weeks. GSH levels were significantly decreased after 4 and 6 weeks. No level showed a significant increase after 2 weeks while SOD activity recorded significant increases after 4 and 6 weeks of ASP treatment. An increase in GST activity was recorded after ASP, being significant after 2 and 6 weeks. A delayed significant increase was observed in CAT activity due to Asp ingestion for 6 weeks. According to the present data, the induction of oxidative stress by ASP administration may depend on the duration of treatment. Short term ASP ingestion does not appear to have an oxidant effect. Nevertheless, ASP ingestion for 4 and 6 weeks induced oxidative stress in the rat cerebral cortex.