Background: Blood is permanently exposed to oxidation stress and therefore has a high antioxidants capacity. Many different factors increasing the demand for the antioxidant capacity can be observed in the stored blood of donors. Consequently, damage to erythrocytes by free radicals may occur. So it is useful to control the alternation of anti-oxidant enzymes in stored blood at different days of storage. The aim of the present study was to determine the alternation of erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities in stored blood.Material and Methods: Blood samples were obtained from 67 donors with average age of 26 years. Samples were collected in CPDA-1 anticoagulation solution. Erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities were determined using Kei Satoh method and kits from Randox. The measurements were performed at the days 1, 7, 14, 21, 28 and 35 of storage. The blood bags were stored after each sampling at 4oC. Data were analyzed using analytical variance statistical test and SPSS version16 software.Results: The erythrocyte levels of erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities decreased significantly at the day 14th (P<0.001) of storage compared to day 1.Conclusion: Our results suggest that during blood storage, antioxidant defense in erythrocytes were depleting gradually depending on the day of storage. Based on our finding a 14 days period can be considered a safe storage limit for transfusion in relation to oxidative stress on the RBCs in storage medium.

Background: Rheumatoid arthritis (RA) is an autoimmune disorder with unknown etiology. In recent years, a great number of studies have investigated the possible role of reactive oxygen species in the etiology and pathogenesis of Rheumatoid Arthritis. The aim of this study was to analyze the level of activities of catalase, glutathione peroxidas (GSH-Px), Super oxide dismotase (SOD) in patients with RA compared with the healthy subjects.Methods: In a case-control study sixty rheumatoid arthritis patients 18-75 years old and 60 healthy sex and age-matched controls were selected, Catalase activity was measured by determining the constant rate (k) of hydrogen peroxide decomposition. GSH-Px activity of plasma was measured with spectrophotometer by Glutathione oxide generation due to GSH-Px. SOD activity is measured by degree of inhibition effect of SOD in generating super oxide radicals by xanthine and xanthine oxidase. C-reactive protein and rheumatoid factor values were determined by agglutination and latex tests.Results: The plasma activity of catalase (p<0.001), GSH-Px (p<0.01), plasma level of hemoglobin and hematocrit (p<0.05) were significantly lower in patients with RA comparing with controls. The reduction in SOD activity was not significant (p>0.05). There was a negative significant relation between Creactive protein and Rheumatoid factor values with the erythrocyte activity of catalase and GSH-Px (p<0.01).Conclusion: These results suggested that oxidative stress plays a very important role in the inflammation and pathogenesis of RA.

Osteoporosis is a metabolic disease characterized by reduction in bone density and susceptibility to deformity and fracture. Some studies show that osteoblasts can create inter-cellular free radicals that lead to cellular death. Superoxide dismutase (SOD) plays an essential role in cell defense against reactive oxygen metabolites. The purpose of this study was to measure the plasma SOD activities in Iranian women with osteoporosis compared to the control group. SOD activity was measured spectrophotometrically at 540 nm in 192 women. Plasma activity of SOD (mean±SD) was 1.72±0.79 mg protein in the control group, 2.05±0.87 mg protein in patients as a whole [(mild Osteopenia+severe osteopenia and osteoporosis) (T-score<-1)] and 2.32±0.91 mg protein in patients with severe osteopenia and osteoporosis (T-score<-1.7). In this study, that plasma activity of SOD was significantly higher in patients than in controls. Furthermore, this difference was more prominent between the controls and patients with severe disease (T-score<-1.7) than patients as a whole. T-score of femur adjusted for age and body mass index (BMI) showed negative significant correlation with plasma activity of SOD.

In this research, the optimization of protein hydrolysis process with the pancreatin enzyme was performed to evaluate the effect of time (30-270 min), temperature (20-60° C) and enzyme concentration (0. 25-3. 25%) on DPPH radical scavenging activity and Fe2+ chelating activity by using the response surface methodology. Optimum conditions to achieve the highest DPPH radical scavenging activity (42. 77%) and Fe2+ chelating activity (78. 57%), were obtained at time of 141. 1 min, temperature of 41. 93 ° C and enzyme concentrations of 2. 14%. Under these conditions, the degree of hydrolysis was 36. 8 ± 0. 35. Comparing the antioxidant power of the hydrolyzed protein and the intact protein showed that the hydrolysis increased the antioxidant activity of the fenugreek protein, significantly. Then, the antioxidant properties of optimum treatment were investigated at concentrations of 10-50 (mg/ml). The highest DPPH radical scavenging activity (50. 65%) and total antioxidant capacity (absorbance 1. 65 at wavelength of 695 nm), hydroxyl radical scavenging activity (69. 03%) and Fe2+ chelating activity (79. 72%) were achieved at concentration of 50 (mg/ml) and reducing power (absorption 0. 8 at wavelength of 700 nm) were achieved at concentration of 40 (mg/ml). The results showed that the hydrolysis of fenugreek protein with the pancreatin enzyme is an effective way to produce antioxidant peptides. So, the bioactive peptides, with significant antioxidant properties, can be used as potential substitute of synthetic antioxidants and as a protein supplement in food formulation to produce functional products with health promotion properties.