Objectives:This study aimed to evaluate the hypoglycemic effects of an ethanol extract of Cassia abbreviata (ECA) bark and the possible mechanisms of its action in diabetic albino rats.Methods:ECA was prepared by soaking the powdered plant material in 70% ethanol. It was filtered and made solvent-free by evaporation on a rotary evaporator. Type 2 diabetes was induced in albino rats by injecting 35 mg/kg body weight (bw) of streptozotocin after having fed the rats a high-fat diet for 2 weeks. Diabetic rats were divided into ECA-150, ECA-300 and Metformin (MET)-180 groups, where the numbers are the doses in mg.kg.bw administered to the groups. Normal (NC) and diabetic (DC) controls were given distilled water. The animals had their fasting blood glucose levels and body weights determined every 7 days for 21 days. Oral glucose tolerance tests (OGTTs) were carried out in all animals at the beginning and the end of the experiment. Liver and kidney samples were harvested for glucose 6 phosphatase (G6Pase) and hexokinase activity analyses. Small intestines and diaphragms from normal rats were used for α-glucosidase and glucose uptake studies against the extract.Results:Two doses, 150 and 300 mg/kg bw, significantly reduced the fasting blood glucose levels in diabetic rats and helped them maintain normal body weights. The glucose level in DC rats significantly increased while their body weights decreased. The 150 mg/kg bw dose significantly increased hexokinase and decreased G6Pase activities in the liver and the kidneys. ECA inhibited α-glucosidase activity and promoted glucose uptake in the rats’ hemi-diaphragms.Conclusion:This study revealed that ECA normalized blood glucose levels and body weights in type 2 diabetic rats. The normalization of the glucose levels may possibly be due to inhibition of α-glucosidase, decreased G6Pase activity, increased hexokinase activity and improved glucose uptake by muscle tissues.

Contamination of vegetables with toxic metals is one of the most important contributing factors to ill health throughout the world, more so because vegetables are considered essential for human health and their consumption is highly recommended by health authorities. The aim of this study was to determine the concentrations of selected essential elements (Fe, Cu, Mn, Mo, Zn) and toxic elements (As, Cd, Cr, Pb) in common vegetables sold for human consumption in supermarkets and open market of Maun village, Botswana. Five vegetables (cabbage, rape, tomatoes, onions and potatoes) were purchased from different selling points, washed with de-ionised water, cut into small pieces and digested with aqua regia on a block digester, following the US. EPA method 200 -7 and analysed for metal content using Inductively Coupled Plasma -Atomic Emission Spectroscopy (ICP-AES). The results showed that concentrations of essential and toxic metals varied with the type of vegetable and also with the market category (supermarket or street vendor). The highest concentration of essential elements was obtained from cabbage with a Zn concentration of 135.4mg/Kg and the lowest was from onion with a Mo concentration of 1.35mg/Kg. For toxic elements the highest concentration was obtained from rape vegetable with a Pb concentration of 4.73mg/Kg and the lowest from the same vegetable with Cr concentration below the detection limit. Also observed was that leafy vegetables, especially cabbage, had the highest concentrations of most trace metals. It was concluded that vegetables sold in Maun had sufficient levels of essential elements but also some had high concentrations of toxic metals. We thus recommend consumption of vegetables from the studied markets with reduced frequency to avoid metal poisoning.

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