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.

Cytotoxic mechanism of Piper gaudichaudianum Kunth essential oil and its major compound nerolidol.

Piper gaudichaudianum Kunth is used in popular medicine as anti-inflamatory and against liver disorders. One of the most studied components of the plant is the essential oil for which chemical analysis revealed (E)-nerolidol as major compound. Recently, we have shown that P. gaudichaudianum essential oil possesses strong cytotoxic effects in mammalian V79 cells. The aim of this study was to analyze the cytotoxicity and mutagenicity of P. gaudichaudianum essential oil and nerolidol using Saccharomyces cerevisiae as model study. Treatment of the XV185-14c and N123 strains with essential oil and nerolidol led to cytotoxicity but did not induce mutagenicity. Our results revealed an important role of base excision repair (BER) as the ntg1, ntg2, apn1 and apn2 mutants showed pronounced sensitivity to essential oil and nerolidol. In the absence of superoxide dismutase (in sod1Δ mutant strain) sensitivity to the essential oil and nerolidol increased indicating that this oil and nerolidol are generating reactive oxygen species (ROS). The ROS production was confirmed by DCF-DA probing assay in Sod-deficient strains. From this, we conclude that the observed cytotoxicity to P. gaudichaudianum essential oil and nerolidol is mainly related to ROS and DNA single strand breaks generated by the presence of oxidative lesions.

Chemical composition and cytotoxic, mutagenic and genotoxic activities of the essential oil from Pipergaudichaudianum Kunth leaves.

We have investigated the chemical composition of Piper gaudichaudianum essential oil, as well as its cytotoxic, mutagenic and genotoxic effects in V79 cells. The chemical analyses showed that the major compounds are (E)-nerolidol (22.4%), alpha-humulene (16.5%), (E)-caryophyllene (8.9%) and bicyclogermacrene (7.4%). Dose-dependent cytotoxic effects were observed in V79 cells treated with essential oil by using clonal survival, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction assay (MTT) and trypan blue exclusion assay (TB), and a significant decrease in survival was observed at concentrations of 0.5 microg/mL and higher. The P. gaudichaudianum essential oil treatment caused DNA strand breaks in V79 cells at concentrations up to 2 microg/mL, as detected by the alkaline comet assay, but did not induce double-strand breaks, as verified by neutral comet assay. It induced a significant increase in the frequency of micronucleated cells at 4, 6 and 10 microg/mL. Moreover, P. gaudichaudianum essential oil significantly increased lipid peroxidation at doses of 0.5 microg/mL and higher, suggesting that the observed oxidant potential can be responsible, at least in part, for its cytotoxic and genotoxic effects.