Modares Journal of Biotechnology

Abstract Diabetes mellitus is a major health problem in the worldwide. Inhibition of DPP-IV is one of the methods to control diabetes type 2. Inhibition of this enzyme may improve glycemic control in diabetics by preventing the rapid breakdown and there by prolonging the physiological action of incretin hormones. Furthermore, improving the antioxidant system in diabetic patients can prevent the occurrence of secondary disease caused by oxidative stress. Therefore, the head of skipjack tuna was hydrolyzed with alcalase enzyme (1/5% of raw material weight) for 4 hours, in order to produce a product with antidiabetic and antioxidant activities. The DPP-IV inhibition activity, DPPH radical scavenging activity and reducing power of hydrolysate were measured. The results showed that the skipjack tuna head protein hydrolysate possess bioactive properties in a concentration dependent manner and increasing the protein concentration leads to a significant increase in bioactive properties of hydrolyzed product (p≤0.05). The IC50 of protein hydrolysate in DPP-IV inhibition and DPPH radical scavenging activities were obtained 1.016±0.02 mg/ml and 0.297±0.015 mg/ml, respectively. Also the reducing power of hydrolysate was 0.176±0.002 in 2.5 mg/ml protein concentration. Overall, according to the obtained results, it can be concluded that protein hydrolysate of skipjack tuna head possess high antioxidant and antidiabetic activities in vitro, and can be used as a food additive to enhance health level if additional research be conducted.

Abstract Free radicals, having one or more unpaired electrons in the outer orbit, which are oxygen-centred free radicals, sometimes known as reactive oxygen species (ROS). The oxidative stress imposed by ROS plays an important role in many chronic and degenerative diseases. The aim of the present research was undertaken to study the antioxidant activity and polyphenolic content in the different extracts of sea urchin Echinometra mathaei. Different extracts (spine, shell, gonad and aristotol lantern) of sea urchin were isolated by three solvents (n- hexan, ethyl acetate, methanol). Antioxidant activity of extracts was assessed by measured reducing power, DPPH free radical scavenging activity and total antioxidant capacity assays, and compared with the synthetic antioxidant butylated hydroxytoluent (BHT) and Ascorbic acid. Total phenolic and flavonoid contents were measured spectrophotometrically. According to the results of the study, highest the reducing power and free radical-scavenging activity of the methanolic shell and methanolic spine, respectively. In total antioxidant capacity assay, the antioxidant activity of aristotol lantern ethyl acetate, spine and gonad n-hexan was higher as compared to that of the ascorbic acid. The highest total phenol and flavonoid compound content per gram of the methanolic spine were 0.0044±0.0003 mg gallic acid equivalents and 24.616±0.7167 mg quercetin equivalents, respectively. Significant differences were observed at P