Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Anti-oxidative, metal chelating and radical scavenging effects of protein hydrolysates from blue-spotted stingray

Tsun-Thai Chai^1,2 , Shi-Ruo Tong², Yew-Chye Law², Nor Ismaliza Mohd Ismai^1,3, Fazilah Abd Manan⁴, Fai-Chu Wong^1,2

¹Centre for Biodiversity Research; ²Department of Chemical Science; ³Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, 31900 Kampar; ⁴Department of Biosciences and Health Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Malaysia.

For correspondence:- Tsun-Thai Chai Email: chaitt@utar.edu.my Tel:+6054688888

Received: 19 April 2015 Accepted: 2 July 2015 Published: 30 August 2015

Citation: Chai T, Tong S, Law Y, Ismai NM, Manan FA, Wong F. Anti-oxidative, metal chelating and radical scavenging effects of protein hydrolysates from blue-spotted stingray. Trop J Pharm Res 2015; 14(8):1349-1355 doi: 10.4314/tjpr.v14i8.5

© 2015 The authors.
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Abstract

Purpose: To evaluate protein hydrolysates and membrane ultrafiltration fractions of blue-spotted stingray for metal chelating and radical scavenging activities, as well as protection against oxidative protein damage.

Methods: Stingray protein isolates were hydrolysed with alcalase, papain and trypsin for 3 h. Alcalase hydrolysate was fractionated by membrane ultrafiltration to yield < 3, 3 - 10 and > 10 kDa fractions. Peptide contents, iron and copper chelating activity, 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and hydroxyl radical scavenging activities, and protection against oxidative protein damage were evaluated.

Results: Three-hour alcalase hydrolysate (3AH) had the highest peptide content and the lowest half maximal effective concentration (EC₅₀) for ABTS radical scavenging (793.9 µg/mL), hydroxyl radical scavenging (6.93 mg/mL), iron chelating (116.4 µg/mL) and copper chelating activity (2136.9 µg/mL) among the hydrolysates. Among the fractions of 3AH, < 3 kDa fraction had the best iron chelating activity, 3 - 10 kDa fraction exhibited the highest ABTS radical scavenging activity, while > 10 kDa fraction showed the best copper chelating activity. The < 3 kDa and 3 - 10 kDa fractions had similar levels of hydroxyl radical scavenging activity to reduced glutathione. The protective effects of 3AH and < 3 kDa fraction against oxidative protein damage were comparable to that of reduced glutathione.

Conclusion: Alcalase is the best protease for producing hydrolysates with metal chelating and antioxidant activities from stingray proteins. Alcalase hydrolysate, specifically its < 3 kDa fraction, has potential for future applications in antioxidant therapy and health food formulation.

Keywords: Dasyatis kuhlii, Membrane ultrafiltration, Protein hydrolysate, Glutathione, Peptide content, Metal chelating, Radical scavenging