Blood Glucose Lowering Effect and Safety of the Aqueous Leaf Extracts of Zanha africana

Abstract

Zanha africana has been used traditionally to manage many diseases including diabetes, however, its antidiabetic activity and safety is not well evaluated. The aim of this study was to determine in vivo hypoglycemic activity and safety of the aqueous leaf extracts of this plant in male Swiss white albino mice. The antidiabetic activity was screened in alloxan induced diabetic mice using oral and intraperitoneal routes. The safety of the extract was studied in mice that were orally and intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording changes in body and organ weights, hematological and biochemical parameters. Mineral composition was estimated using total reflection X-ray fluorescence system and atomic absorption spectrometry. Phytochemical composition was assessed using standard procedures. The extract showed hypoglycemic activity at dose levels of 50, 100, 200, 300 mg/kg body weight. Administration of 1 g/kg body weight of the extract decreased the body weight gain using both routes. Intraperitoneal administration of the same dose increased the organ to body weight percentages of liver, brain and kidney, and elevated white blood cell count, lymphocyte count, and levels of γ-glutamyl transpeptidase, total bilirubin and direct bilirubin and deceased levels of aspartate aminotransferase and creatinine. Increase in levels of mean corpuscular hemoglobin, γ-glutamyl transpeptidase, lactate dehydrogenase and creatine kinase, and decrease in levels of platelets, alanine transaminase, aspartate aminotransferase, urea, creatinine, total bilirubin and direct bilirubin was recorded in mice orally administered with 1 g/kg body weight of the extract. The extract contained tannins, phenols, flavonoids, saponins, and alkaloids. Sodium, Chlorine, Potassium, Calcium, Titanium, Vanadium, Chromium, Manganese, Iron, Copper, Zinc, Arsenic, Cadmium, Magnesium, Nickel and Lead were present in the extracts at levels below the recommended daily allowance. The observed hypoglycemic activity and slight toxicity could be associated with the phytochemicals and mineral/ trace elements present in this extract.