Abstract

The present comparative study was undertaken to determine the hypoglycemic effect of 96% ethanolic extracts of Eucalyptus globulus (Myrtaceae) leaves, Salviaofficinalis (Lamiaceae) leaves growing in Algeria and Guiera senegalensis(Combretaceae) leaves growing in Sudan in glucose loaded albino rats and to assess their toxicity. Preliminary phytochemical screening of leaf extracts of the three plants revealed the presence of carbohydrates, tannins, flavonoids, sterols and triterpenes, alkaloids and terpenoids. Graded doses of the aqueous ethanolic leaf extracts of the three plants, 200 to 400 mg/kg were separately administered orally to groups of glucose loaded rats. The hypoglycemic effect of the extracts was compared to glibenclamide 10 mg/kg in fasted normal rats. Following the treatment, relatively moderate to high doses of the three extracts produced a dose-dependent significant reduction in blood glucose levels which was most significant at the dose 400 mg/kg. The median lethal concentration LC₅₀ in brine shrimps was 55.95 mg/ml for E. globulus; 37.20 mg/ml for S. officinalis and 26.94 mg/ml for G.senegalensis compared to a standard antitumor drug Etopside. The results clearly demonstrated that the 96% alcoholic leaf extracts of the three plants had a significant blood-glucose lowering potential in glucose loaded rats with minimum toxicity.

Key words: Sudan, Algeria, leaf extracts, Eucalyptus globulus, Salvia officinalis,Guiera senegalensis, hypoglycemic effect, toxicity.