Effects of crude hydroalcoholic extract of Syzygium cumini (L.) Skeels leaves and continuous aerobic training in rats with diabetes induced by a high-fat diet and low doses of streptozotocin.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Syzygium cumini (L.) or Skeels (Myrtaceae) are widely used in Brazilian folk medicine to treat diabetes. AIM OF THE STUDY: The present study evaluated the functional capacity, biochemical parameters, oxidative stress and DNA damage from eight weeks of intervention with a crude hydroalcoholic extract of S. cumini leaves (EBH) and continuous aerobic training (TAC) in diabetic (D) rats. MATERIALS AND METHODS: A hydroalcoholic (50%) extract was prepared by ultrasound and phytochemical parameters (total phenols, total tannins and myricetin content) were analyzed. Thirty-seven male Wistar rats were divided into five groups: normoglycemic controls (CONT), diabetic controls (D-CONT), diabetics treated with extract (D+EBH), trained diabetic (D+TAC) and diabetics treated with extract and trained (D+EBH+TAC). Functional capacity was assessed with a maximum exercise capacity test; biochemical parameters with enzymatic kits; oxidative stress by superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and oxidized dichlorofluorescein (DCF), and the DNA damage by the comet assay. RESULTS: The D+TAC and D+EBH+TAC groups showed better functional capacity at the end of interventions. The D+EBH group showed glucose and triglyceride reduction, lowest DNA damage index in the blood, liver, kidney, heart, lung and gastrocnemius muscle, improved SOD levels in the liver, kidney and lung, improved CAT levels in the kidney and lower lipid peroxidation in all tissues studied, compared to the D-CONT group. The exercise (D+TAC) was effective in reducing triglycerides, improving SOD levels in the lung, reducing lipid peroxidation in all tissues studied and reducing the DCF oxidation in the kidney, in addition to protecting against DNA damage in the blood and heart. However, the additive effect of the intervention protocols when combined (EBH+TAC) was observed only in improving the gastrocnemius SOD levels. The phytochemical analyses showed a high content of phenols and the presence of myricetin glycosides. CONCLUSION: The findings in this study suggest a crude hydroalcoholic extract of S. cumini leaves has potential hypoglycemic, hypolipidemic and protective properties acting against oxidative stress and against DNA damage, probably due to its phenols and myricetin glycoside content and the antioxidant properties of these constituents. Moreover, exercise was suggested to have beneficial effects on diabetes, improving functional capacity, ameliorating blood triglyceride control and decreasing lipid peroxidation, but with no effects on ameliorating blood glucose levels. The association of intervention protocols presented an additive effect on the antioxidant SOD activity in the muscle cells of diabetic rats.

Glutathione peroxidase induction protects Saccharomyces cerevisiae sod1deltasod2delta double mutants against oxidative damage.

Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and the double mutant) were subjected to H2O2 stress in the stationary phase. The highest sensitivity was observed in the sod2delta mutant, while the sod1deltasod2delta double mutant was not sensitive. Sod mutants had lower catalase activity (44%) than wild-type cells, independent of H2O2 stress. Untreated cells of sod1deltasod2delta double mutants showed increased glutathione peroxidase activity (126%), while sod1delta had lower activity (77%) than the wild type. Glutathione levels in sod1delta were increased (200-260%) after exposure to various H2O2 concentrations. In addition, the highest malondialdehyde levels could be observed without H2O2 treatment in sod1delta (167%) and sod2delta (225%) mutants. In contrast, the level of malondialdehyde in the sod1deltasod2delta double mutant was indistinguishable from that of the wild type. These results suggest that resistance to H2O2 by sod1deltasod2delta cells depends on the induction of glutathione peroxidase and is independent of catalase, and that glutathione is a primary antioxidant in the defense against H2O2 in stationary phase sod1delta mutants.

Glutathione peroxidase induction protects Saccharomyces cerevisiae sod1deltasod2delta double mutants against oxidative damage

Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and the double mutant) were subjected to H2O2 stress in the stationary phase. The highest sensitivity was observed in the sod2delta mutant, while the sod1deltasod2delta double mutant was not sensitive. Sod mutants had lower catalase activity (44 percent) than wild-type cells, independent of H2O2 stress. Untreated cells of sod1deltasod2delta double mutants showed increased glutathione peroxidase activity (126 percent), while sod1delta had lower activity (77 percent) than the wild type. Glutathione levels in sod1delta were increased (200-260 percent) after exposure to various H2O2 concentrations. In addition, the highest malondialdehyde levels could be observed without H2O2 treatment in sod1delta (167 percent) and sod2delta (225 percent) mutants. In contrast, the level of malondialdehyde in the sod1deltasod2delta double mutant was indistinguishable from that of the wild type. These results suggest that resistance to H2O2 by sod1deltasod2delta cells depends on the induction of glutathione peroxidase and is independent of catalase, and that glutathione is a primary antioxidant in the defense against H2O2 in stationary phase sod1delta mutants.

Inlfuence of high-viscosity vehicles on miotic effect of pilocarpine.

Gel formulations containing 2% pilocarpine hydrochloride were prepared from ethylene maleic anhydride, carbomer, hydroxyethylcellulose, polyacrylamide, ethylhydroxyethylcellulose, hydroxypropylcellulose, and poly(methylvinyl ether--maleic anhydride). The viscosity characteristics of each formulation were evaluated from rheograms developed at 37 degrees using a cone and plate viscometer. Single-point viscosities were determined at room temperature using a single-point rotational viscometer. Plastic viscosity parameters correlated to miosis durations in the rabbit following ophthalmic dosing of 50 microliters. Carbomer formulations varying in concentration between 0.9 and 5.0% (w/w) showed a discontinuous relationship when either yield value or plastic viscosity was plotted against miosis durations. At carbomer concentrations above 3%, miosis durations increased 1.5-fold. Above and below this range, plastic parameters did not correlate to miosis duration. It was reasoned that the increased duration was a consequence of the gel's increased yield value such that appreciable in vivo thinning of the gel does not take place with eyelid and/or eyeball movements. As a result, the residence time of the drug in the eye would be expected to increase, thus promoting an increased duration.