This study evaluated the in vitro antioxidant activity of water (VAWE) and ethanol (VAEE) extracts of the leaf of Vernonia amygdalina. The antioxidant activity of each extract was evaluated using various radicals or oxidation systems. The total phenolic or flavonoid contents and their correlation with total antioxidant activity were also evaluated. VAEE exhibited antioxidant scavenging potential comparable to butylated hydroxyanisole (BHA), but higher than butylated hydroxytoluene (BHT) or VAWE. The total antioxidant scavenging activity of the extracts measured as the millimolar (mM) equivalent of vitamin C gave VAEE a 10.09 ± 1.63, which is comparable to BHA with a 9.31 ± 1.17, but higher than VAWE with an 8.75 ± 1.28 or BHT with a 6.14 ± 2.01. Extracts inhibited bleaching of B-carotene, oxidation of linoleic acid and lipid peroxidation induced by Fe2+/ascorbate in a rat liver microsomal preparation. The total flavonoid and phenolic contents correlated positively with total antioxidant activity. The total flavonoid content also correlated well with total phenolic. Extracts of V. amygdalina contain natural antioxidants, have the potential to act as antioxidants against aqueous radicals and reactive species ions. The total phenolic content of the extracts is related to its total flavonoid, and it may be responsible for its total antioxidant activity.

Introduction: Diabetes is a disease that constitutes multiple sources of free radicals, thus oxidative stress is expected to have a double impact. Since oxidative stress is mediated by hyperglycemia-induced generation of free radical, it is supposed that compounds with hypoglycemic and antioxidative properties would be useful antidiabetic agents. Our study investigated the use of V. amygdalina as a potential hypoglycemic and antioxidative agent by testing its effect on the antioxidant biomarkers and lipid peroxidation. Methods: Dried leaves of V. amgydalina were extracted for 48 hrs and freeze dried. Acute toxicity was investigated in 25 rats. Thirty six rabbits were divided into 6 groups: groups I -III were normal; diabetes was induced in groups (IV -VI). Groups I and IV were normal and diabetic controls respectively. The animals were treated with aqueous leaf extract of V. amygdalina. Blood samples were collected and used for the study. Results: The reduction in body weight in the diabetic groups was regained following administration of the extract of V. amgydalina. The extract is considered safe and had little or no effect on blood glucose, MDA and GSH levels of the normal rabbits. Extract significantly reduced glucose and MDA concentrations but increased GSH levels in the diabetic rabbits. Similarly, the extract had no effect on the activities of SOD, CAT and GPx in normal rabbits, however in diabetic rabbits, the enzymes activities increased dose-dependently. Conclusion: This finding provides basis for the use of V. amgydalina as potential antidiabetic antioxidant agent and may be useful for its hypoglycemic property. INTRODUCTIONWith oxidative stress linked to metabolic or vascular disorder, diabetes becomes the best disease for studying the consequences of oxidative stress and its treatment. Diabetes mellitus is a multifactorial disease characterized by hyperglycemia, [2,3] lipoprotein abnormalities, [4] raised basal metabolic rate, [5] defect in reactive oxygen species scavenging enzymes [6] and high oxidative stress induced by the generation of highly reactive free radicals which are also involved in pancreatic destruction. [2,7] Insufficient removal of these free radicals can lead to oxidative damage to membranes; enhance susceptibility to lipid peroxidation, enzyme inactivation and nucleic acid damage. [8,6] Since oxidative stress is mediated by hyperglycemiainduced generation of free radical, it became clear that lowering blood glucose as well as scavenging the free radicals may ameliorate the oxidative stress thus providing an effective strategy for reducing diabetic mellitus and its complications. Attenuation of Oxidative Damage in Alloxan Induced[9] Hence compounds with both hypoglycemic and antioxidative properties would be very useful antidiabetic agents. We therefore considered a known hypoglycemic plant, Vernonia amygdalina and its effect on some endogenous biomarkers of oxidative stress: superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and lipid peroxidation...

Launaea taraxacifolia (Wild.) Amin ex. Jeffery belongs to family Asteracaea. The plant is used for treatment of diseases and eaten as vegetable in Nigeria. This study investigated the ameliorative potentials of L . taraxacifolia leaf partitions in alloxan induced diabetic complications. Male Albino rats were divided into eleven groups of five rats each. Diabetes was induced following intraperitoneal administration of 150 mg/kg alloxan monohydrate and was treated with 200 and 300 mg/kg of each partitioned fractions. Hyperglycemia was reversed in all treated rats within seven days of treatments. Rats treated with the partitions showed significant increase in hematological parameters compared with diabetic control. N-hexane fraction had the best overall effect against oxidative stress particularly on heart and pancreas reduced glutathione (GSH), superoxide dismutase (SOD) and kidney glutathione S-transferase (GST) activities. The various degrees of degeneration observed in the kidney, liver, pancreas and heart of the untreated diabetic rats were milder in rats treated with partitions. The results therefore revealed the ameliorative potentials of the partitioned fractions of L. taraxacifolia leaf extract against diabetes mellitus complications via activation of the antioxidant enzymes.