Effects of Solvent Fractions of Caylusea abyssinica (Fresen.) Fisch. and Mey. on Blood Glucose Levels of Normoglycemic, Glucose Loaded and Streptozotocin-Induced Diabetic Rodents

In Ethiopia the leaves of Caylusea abyssinica (Fresen.) Fisch.&Mey. (Family: Resedaceae) are used as a cooked vegetable and also for the management of diabetes mellitus in folk medicine. The present study was carried out to investigate effects of solvent fractions of the leaves of C. abyssinica on Blood Glucose Levels (BGLs) of normoglycemic, glucose loaded and streptozotocin-induced diabetic rodents. Solvent fractions were prepared by successive extraction of the leaves in a soxhlet apparatus with chloroform and methanol, and then further maceration of the marc left with distilled water. Phytochemical analysis indicated presence of alkaloids, terpenes, flavonoids, tannins, reducing sugars and steroids. Acute toxicity test showed that all the fractions were safe at doses of up to 2 g/kg. Whilst only the methanol fraction at a dose of 300 mg/kg produced significant hypoglycemic effect 4 h after treatment, both the methanol and aqueous fractions significantly decreased BGL of glucose loaded and streptozotocin-induced diabetic rodents. A reduction of 55.37% (p<0.05) and 59.54% (p<0.001) in BGL was observed within 2 h of oral glucose tolerance test by 200 and 300 mg/kg of the methanol fraction, respectively. The same fraction at doses of 200 and 300 mg/kg reduced BGL by 80.24% (p<0.001) and 81.05% (p<0.001), respectively, whereas the aqueous fraction at a dose of 300 mg/kg lowered BGL by 55.33%. It was therefore concluded that the reputed application of C. abyssinica leaves for the management of diabetes in traditional medical practice is well founded.