Influence of oxidative stress on the antibacterial activity of betulin, betulinic acid and ursolic acid.

Contribution of reactive oxygen species and oxidative stress in the antibacterial activities of betulin, betulinic acid and ursolic acid against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus was investigated. The minimum inhibitory concentrations of betulin, betulinic acid and ursolic acid against E. coli, P. aeruginosa and S. aureus are 1024-, 256- and 1024-µg/mL; 512-, 256- and 256 µg/mL; 256-, 256- and 64 µg/mL respectively. Cell viability of betulin-, betulinic acid- and ursolic acid-treated bacteria decrease in time dependent manner. Treatment of bacteria in the presence of 2,2'-bipyrydyl increased cell viability. Superoxide anion radical production increased significantly (p < 0.05) in bacterial cells-treated with betulin, betulinic acid and ursolic acid. Furthermore, NAD+/NADH ratio increased significantly (p < 0.05) in betulin-, betulinic acid- and ursolic acid-treated bacteria. Similarly, level of reduced glutathione in E. coli, P. aeruginosa and S. aureus decreased significantly with corresponding increase in glutathione disulphide, malondialdehyde and fragmented DNA following betulin, betulinic acid and ursolic acid treatments. It is evident from the above findings that betulin, betulinic acid and ursolic acid enhanced electron transport chain activity in E. coli, P. aeruginosa and S. aureus leading to increased ROS generation, Fenton reaction, lipid peroxidation, fragmented DNA and consequentially bacterial death.

Antidiabetic Activity of Triticum aestivum Seed-Based Diet on Alloxan-Induced Diabetic Rats.

The antidiabetic activity of Triticum aestivum seed-based diet on alloxan-induced diabetic rats was investigated. Forty-eight male and female albino rats of four groups were used for this study. Rats were sacrificed on day 28 and organs of interest were excised. Triticum aestivum seed-based diet significantly (p < .05) reversed the levels of fasting blood glucose, albumin, globulin, bilirubin, urea, creatinine, Na+, and K+. In addition, diabetic rats fed Triticum aestivum seed-based diet had significantly (p < .05) increased insulin and glycogen concentrations, activities of hexokinase, catalase, superoxide dismutase, and glutathione peroxidase and the levels of hematological parameters studied. Diabetic rats fed on Triticum aestivum seed had significantly (p < .05) reduced activities of glucose-6-phosphatase and fructose 1,6-diphosphatase and concentration of MDA and reversed activities of AST and GGT; ALP and regeneration of liver, kidney, and pancreas tissues compared favorably with the control group from histological examination results. Consumption of this diet may be useful for diabetes mellitus patients in ameliorating diabetes mellitus and its complications.

Antidiabetic and antidyslipidemic activities of aqueous leaf extract of Dioscoreophyllum cumminsii (Stapf) Diels in alloxan-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Dioscoreophyllum cumminsii (Stapf) Diels leaves are used in the management of diabetics in Nigeria. Thus, the antidiabetic activity of aqueous D. cumminsii leaf extract and its capability to halt oxidative stress and dyslipidemia in alloxan-induced diabetic rats was investigated. METHODOLOGY: Antidiabetic was evaluated in alloxan-induced diabetes rats. Diabetic rats were treated with 50, 100 and 200mg/kg body weight of the extract. RESULT: The aqueous extract of D. cumminsii leaves significantly reduced blood glucose level in a dose dependent manner with highest dose producing 72% reduction after 21 days administration, which was compared significantly (P<0.05) with the control group and glibenclamide treated groups. Similarly, aqueous extract of D. cumminsii significantly reversed reduction in insulin in alloxan-induced diabetic rats. Alloxan-induced diabetic mediated alterations in liver and serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol (HDLc), low density lipoprotein cholesterol (LDLc) and very low-density lipoprotein cholesterol (VLDLc) were significantly (P<0.05) restored by the extract. Aqueous extract of D. cumminsii leaves significantly attenuated the decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase in the liver and pancreas of alloxan-induced diabetic rats. Elevation in the concentration of malondialdehyde was significantly (P<0.05) lowered by D. cumminsii leaves extract. The diabetic-mediated alteration in the architecture of liver was alleviated by the extract. CONCLUSION: Overall, aqueous extract of D. cumminsii leaves at all doses investigated reduced blood glucose level and prevented oxidative stress and dyslipidemia in alloxan-induced diabetic rats.