Biochemical studies on some natural antioxidants

The biological activity of the natural antioxidant vitamin C can be enhanced by the presence of some other active natural antioxidants, such as gallic and tannic acid. The current study was conducted to determine what concentrations and combinations of antioxidants (vitamin C, gallic acid and tannic acid) were capable to produce synergistic antioxidant effects. Scavenging capacities of solutions of the selected compounds alone and in different combinations were measured using the stable free radical 1,1-diphenyl-2-picrylhy-drazyl (DPPH) method. The results showed that the mixture binary that contained vitamin C (5.0 µM) and tannic acid (5.0 µM) had the highest SEs. The results obviously demonstrated that the antioxidant property of this combination was substantially superior to the sum of the individual antioxidant effects, and these interactions can enhance the antioxidant effectiveness of these natural antioxidants. Also in the current study, the hepatoprotective activity of the natural antioxidant against CCl4-induced acute hepatic injury (on male albino rats). Results in significantly elevated (p0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT) and creatinine compared to controls. On the liver, significantly elevated levels (p0.05) of malondialdehyde (MDA) and lowered levels (p0.05) of glutathione-S-transferase (GST) were observed following CCl4 administration. Quantitative and qualitative analysis of catalase (CAT) and superoxide dismutase (SOD) revealed lower activities of these antioxidant enzymes on the liver of CCl4- administered rats. An analysis of the isozyme pattern of these enzymes revealed variations in relative concentration presumably due to hepatotoxicity. Histopathological studies confirmed the hepatoprotective effect conferred by the natural antioxidants. The results could guide in the formulation and development of functional food products that have high antioxidant potency and suggested that natural antioxidant is able to significantly alleviate the hepatotoxicity induced by CCl4 in the rats.