Although zinc (Zn) deficiency has been associated with Insulin resistance, and altered Zn metabolism (e.g., hyperzincuria, lownormal plasma Zn concentrations) may be present in diabetes, the potential effects of Zn on modulation of insulin action in Type II diabetes have not been established. The objective of this study was to compare the effects of dietary Zn deficiency and Zn supplementation on glycemic control in db/db mice. Weanling db/db mice and lean Iittermate controls were fed Zndeficient (3 ppm Zn; dbZD and InZD groups), Zn-adequate control (30 ppm Zn; dbC and InC groups) or Zn-supplemented (300 ppm Zn; dbZS and InZS groups) diets for 6 weeks. Mice were assessed for Zn status, serum and urinary indices of diabetes, and gastrocnemius insulin receptor concentration and tyrosine kinase activity. Fasting serum glucose concentrations were significantly lower in the dbZS group compared with the dbZD group (19.3: 2.9 and 27.9: 4.1 mM, respectively), whereas the dbC mice had an intermediate value. There was a negative correlation between femur Zn and serum glucose concentrations (r =-0.59 for lean mice, P = 0.007). The dbZS group had higher pancreatic Zn and lower circulating insulin concentrations than dbZC mice. Insulin-stimulated tyrosine kinase activity In gastrocnemius muscle was higher in the db/db genotype, and Insulin receptor concentration was not altered. In summary, dietary Zn supplementation attenuated hyperglycemia and hyper-Insullnemia in db/db mice, suggesting that the roles of Zn In pancreatic function and peripheral tissue glucose uptake need to be further investigated.

Experimental studies that aimed to determine the effects of crude aqueous resin extracts of the Commiphora swynnertonii on plasma cholesterol levels and weight changes were carried out in rats (Rattus rattus). A total of 24 experimental rats divided into four groups with equal sample size (n=6) were used. Group one (G1) served as negative control that received 0.5ml of distilled water (0 mg/kg) orally. Groups 2 (G2), 3 (G3) and 4 (G4) received 50, 100, and 200 mg/kg body weight orally on daily basis for 21 days respectively. Results revealed a significant decrease (P < 0.05) in the body weight and on cholestrol levels between the treated and the control groups in a dose dependent manner (R 2 = 0.89). Commiphora swynnertonii resin lowered cholesterol level by 54, 76 and 79% and weight changes by 18, 31 and 23% for the exposed rats at concentrations of 50, 100 and 200 mg/kg BW respectively. The rats were able to tolerate resin at concentrations lower than 100 mg/kg BW. At higher (>100 mg/kg) doses, few rats showed signs of illness including diarrhoea and finally death. Based on these results, C. swynnertonii has a potential to serve as an anti-cholesterol agent with body weight lowering properties.

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