No abstract

The antihyperglycemic and antioxidant effects of water extract of local Viscum album in alloxanizedrats were investigated. This study performed during 2009 in Babol University of medical sciences (Mazandaran Province, Iran). V. album leaves growing on oaks collected and extracted with hot water. The 90 animals that were used in this investigation were male Wistar rats. 60 rats were gavaged with 500 and 1000 mg/kg/day of V. album extract. One hour after final feeding, freshly prepared alloxan injected subcutaneously. Then blood glucose level was measured according to glucose oxidase method. The antioxidant activity of serum was determined by FRAP assay and serum insulin level was measured with ELISA. The administration of V. album extract (500 and 1000 mg/kg/day) significantly reduced the increase in serum glucose concentration in alloxan-hyperglycemic rats. Both the extracts from V. album enhance the serum insulin level as compared to control rats. Serum antioxidant activity in low dose of extract was significantly higher at 48 and 72 h after alloxan injection. Serum antioxidant activity in the high dose was significantly higher at 24, 48 and 72 h. This study demonstrated that V. album extract reduced the blood glucose and increases the antioxidant power of alloxanized-rats. Much more work is clearly needed before phytotherapy for diabetes can be advanced to the clinic.

BackgroundResveratrol is a naturally occurring polyphenol compound mainly found in grapes and red wine. The evidence has suggested that resveratrol has an antioxidant effect. However, the results are inconsistent and inconclusive. Thus, we conducted a systematic review and meta-analysis to evaluate the effect of resveratrol supplementation on markers of oxidative stress.MethodsWe searched PubMed, ISI Web of Science, EMBASE, Scopus and the Cochrane library up to December 2018 to identify randomised controlled trials (RCTs) assessing resveratrol supplementation effects on oxidative markers. Heterogeneity, publication bias, risk of bias and subgroup analysis were analysed. This meta-analysis was conducted in accordance with the guidelines of the Preferred ReportingItems for Systematic Reviews and Meta-Analysis (PRISMA).ResultsMeta-analysis of data from 12 RCTs did not support significant effect of resveratrol supplementation on circulating levels of superoxide dismutase (SOD) (standardized mean difference (SMD) (1.12), (95% CI −0.91 to 3.1), p=0.28), catalase (CAT) (SMD (−0.07), (95% CI −1.4 to 1.3), p=0.92) and glutathione peroxidase (GPx) (SMD (−0.76), (95% CI −2.56 to 1.04), p=0.40). Although, resveratrol supplementation increased significantly circulating total antioxidant capacity (TAC) concentrations (SMD (0.52), (95% CI −0.02 to 1.07), p=0.05). Severe heterogeneity was observed between studies, and no obvious publication bias was observed in included RCTs.ConclusionCollectively, our findings of available RCTs did no show any benefit of resveratrol supplementation on SOD, CAT and GPx except for TAC. Well-designed RCTs are necessary to confirm these results.

Cholesterol oxidase is a bifunctional bacterial flavoenzyme which catalyzes oxidation and isomerization of cholesterol. This valuable enzyme has attracted a great deal of attention because of its wide application in the clinical laboratory, synthesis of steroid derived drugs, food industries, and its potentially insecticidal activity. Therefore, development of an efficient protocol for overproduction of cholesterol oxidase could be valuable and beneficial in this regard. The present study examined the role of various parameters (host strain, culture media, induction time, isopropyl ß-D-1-thiogalactopyranoside concentration, as well as post-induction incubation time and temperature) on over-expression of cholesterol oxidase from Chromobacterium sp. DS1. Applying the optimized protocol, the yield of recombinant cholesterol oxidase significantly increased from 92 U/L to 2115 U/L. Under the optimized conditions, the enzyme was produced on a large-scale, and overexpressed cholesterol oxidase was purified from cell lysate by column nickel affinity chromatography. K m and V max values of the purified enzyme for cholesterol were estimated using Lineweaver-Burk plot. Further, the optimum pH and optimum temperature for the enzyme activity were determined. This study reports a straightforward protocol for cholesterol oxidase production which can be performed in any laboratory.