Rozanova S. Influence of low temperatures on antioxidant properties of placental extracts

Subject - antioxidant properties of water-saline human placenta extracts. Aim - to investigate the influence of hypothermia and low temperatures on human placenta extract antioxidant properties. Methods: - gel-chromatography, spectrophotometrical methods of antioxidant activity assessment, spectrophotometrical assays of erythrocyte structure state, the ESR method of spin probes, the statistical analysis. The thesis is dedicated to studying the influence of freezing down to -20, -80 and -196°С (with the rates of 1-2, 30 and 100°С/min correspondingly) with following thawing on human placenta extracts antioxidant properties. It has been established that character of extract antioxidant properties alterations depends on the freezing rate and depth. The model experiments concerning the influence of different freeze-thawing protocols on antioxidant activity of proteins (albumin, cytochrome C, glucose oxidase) have been carried out. The character of low temperature influence on proteins antioxidant properties has been shown to be closely connected with their structure. Comparative characteristic of hypothermic and low temperature storage on extract antioxidant properties as well as comparative analysis of antioxidant properties of extracts obtained from fresh placenta and the one after low temperature storage are provided. The data concerning HPEs protective activity toward erythrocytes under oxidative stress and increasing this activity after freezing-thawing are presented.