Antidiabetic and antioxidant activity of Terminalia belerica. Roxb.

Effect of continuous administration of dried 75% methanolic extract of fruits of Terminalia belerica (Combretaceae) suspended in water was studied in alloxan induced hyperglycemia and antioxidant defense mechanism in rats. T. belerica prevented alloxan-induced hyperglycaemia significantly from 6th day of administration and there was 54% reduction on 12th day. Oxidative stress produced by alloxan was found to be significantly lowered by the administration of T. belerica extract. This was evident from a significant decrease in thiobarbituric acid reactive substances, conjugated dienes and hydroperoxides in blood and liver respectively. Similarly, decreased glutathione level produced by alloxan was increased by the administration of the extract in blood and liver. However the increase was not significant. Superoxide dismutase which was decreased by alloxan was significantly increased from 9th day in blood and liver of drug treated group. Similarly there was significant increase in the activity of catalase in blood and liver. Decrease in glutathione peroxidase by alloxan administration was found to be increased significantly in the blood and liver from 9th day by extract treatment. Glutathione reductase also was found to be increased in blood and liver. These results suggested that T. belerica fruit extract possessed anti-diabetic and anti-oxidant activity and these activities may be interrelated.

Antidiabetic activity of Aegle marmelos and its relationship with its antioxidant properties.

Oxidative stress induced by alloxan has been shown to damage pancreatic beta-cell and produce hyperglycemia in rats. Aegle marmelos leaf extract is being used in Ayurveda as a medicine for diabetes. The present study examined the action of Aegle marmelos against experimental diabetes as well as the antioxidant potential of the drug. A methanolic extract of Aegle marmelos was found to reduce blood sugar in alloxan diabetic rats. Reduction in blood sugar could be seen from 6th day after continuous administration of the extract and on 12th day sugar levels were found to be reduced by 54%. Oxidative stress produced by alloxan was found to be significantly lowered by the administration of Aegle marmelos extract. This was evident from a significant decrease in lipid peroxidation, conjugated diene and hydroperoxide levels in serum as well as in liver induced by alloxan. Catalase and glutathione peroxidase activity in blood and liver were found to be increased from 9th day onwards after drug administration. Superoxide dismutase and glutathione levels were found to be increased only on 12th day. These results indicate that Aegle marmelos extract effectively reduced the oxidative stress induced by alloxan and produced a reduction in blood sugar.

Hypoglycemic effect of methanol extract of Phyllanthus amarus Schum & Thonn on alloxan induced diabetes mellitus in rats and its relation with antioxidant potential.

Methanolic extract of P. amarus was found to have potential anti-oxidant activity as it could inhibit lipid peroxidation, and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 104 microg/ml and the concentrations needed to scavenge hydroxyl and superoxide radicals were 117 and 19 microg/ml respectively. The extract was found to reduce the blood sugar in alloxan diabetic rats at 4th hr by 6% at a dose level of 200 mg/kg body wt and 18.7% at a concentration of 1000 mg/kg body wt. Continued administration of the extract for 15 days produced significant (P < 0.001) reduction in blood sugar. On 18th day after alloxan administration values were almost similar to normal in the group taking 1000 mg/kg body wt.