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Evaluation of medicinal plants for their antidiabetic activities has increased considerably around the world as well as in Algeria. Olea europaea var. sylvestris, commonly called Ezzeboudj, is traditionally used by Tlemcen population in Algeria, for treating diabetes mellitus. In this work, we studied the antioxidant activity of wild olive leaves crude extracts, by free radical DPPH scavenging method and iron reduction FRAP. On the other hand, evaluation of the ability of the extracts to inhibit α-amylase activity. The qualitative phytochemical screening carried out on O. europaea var. sylvestris leaves extracts showed the presence of tannins, sterols and triterpenes, saponins, flavonoids and terpenoids. A quantitative analysis of the crude extracts showed significant levels of total polyphenols and flavonoids in hydroacetonic extract, with an amount of 228,45 ± 0,03 mg GAE /g and 204,8 ± 0,04 mg CE /g, respectively. The results obtained from the antioxidant activity showed a high scavenging activity for hydroacetonic extract with an IC50 of 7,95 ± 0,16 µg/ml. In vitro tests carried out on the inhibitory of α-amylase activity, revealed an inhibitory effects, specifically with hydromethanolic extract in a concetration-dependent manner, with an IC50 value of 0,91 ± 0,02 mg/ml. These findings reveals that O. europaea var. sylvestris leaves could represent an interesting source of antioxidants and allow to the development of new antidiabetic agents.

Background: Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia resulting from defects in insulin secretion, insulin action, or both. There are many classes of drugs used for treatment, and these include insulin sensitizers, insulin secretagogues, and agents that delay the absorption of carbohydrates from the bowel. This study intends to investigate the effect of crude extract from a plant from South Algeria Traganum nudatum (Chenopodiaceae) on glucose uptake in liver slices isolated from Wistar rats. Methods: The liver slices were incubated for 90 min at 37° in normoglycaemic (1g/l of glucose) and hyperglycaemic (3g/l of glucose) KRBA Krebs Ringer Bicarbonate Albumin 4% media using 24 well-polyethylene plates. In each, well different concentrations of insulin (10, 50 and 100µU/ml) and hydromethanolic crude extract (100, 200 and 500µg/ml) were added. After every 30 minutes, aliquots of the culture media were assayed for the determination of glucose left. Results: Tests showed that the glucose left after 90 minutes in the media which contained insulin at 100µg/ml was the lowest (0.44 and 1.41 )g/l in the normo and hyperglycaemic media respectively, which reflect that insulin at this concentration was the most effective on the stimulation of glucose uptake. The extract had the highest effect at 500µg/ml, the concentrations of glucose left after 90 minutes of incubation were found to be (0.38 and 1.31)g/l in the normoglycaemic and hyperglycaemic media respectively. Conclusion: From the obtained results, it can be concluded that our extract seems to have an insulin-like effect on glucose uptake in liver slices isolated from Wistar rats.

Objectives Juglans regia L. is largely used by diabetic population, but its bark is scarcely investigated. The major aim of this study was to investigate the effect of the hydro-methanolic extract and fractions of J. regia L. barks on normoglycemic and diabetic rats through the evaluation of some biochemical parameters. Methods Phenolic enriched extracts were investigated for their effect on normoglycemic and diabetic rats through the determination of fasting blood glucose levels in short- and long-term. As well as plasma total cholesterol, triglycerides, insulin, urea, creatinine, alanine amino transferase (ALT) and aspartate amino transferase (AST) levels were measured after 28 days of treatment. Furthermore, the phytochemical composition was assessed by standard methods. Results Among the different extracts tested, the n-Butanol fraction presented the highest amounts of total phenolic, total flavonoids and flavonol contents (745 ± 0.6 mg GAE g−1, 162 ± 0.78 mg CE g−1 and 56.02 ± 0.92 mg QE g−1, respectively) and it found to be the most effective to decrease plasma total cholesterol, triglycerides and FGLs in treated diabetic rats in both short- and long-term treatment, mainly the dose 200 mg/kg after 28 days of treatment which found to be more effective than glibenclamide. This fraction also revealed pronounced improvement in liver and renal profiles. Conclusions J. regia L. barks had an important antidiabetic role similar to the reference glibenclamide. This may be related to the high contents of phenolic compounds.