EVALUATION OF FREE RADICAL SCAVENGING ACTIVITY OF 2-HYDROXYBENZYL-CHITOOLIGOSACCHARIDE

Abstract

Chitooligosaccharide (COS), an oligosaccharide derived from chitosan, is known for its biodegradability, non-toxicity, and free radical scavenging properties. The incorporation of a 2-hydroxybenzyl group into the COS structure yields a derivative (HBCOS) with significantly enhanced antioxidant activity, while preserving the original carbohydrate backbone. In this study, HBCOS was synthesized via a Schiff base reaction between COS and 2-hydroxybenzaldehyde under optimal conditions (pH 3.5, 45 °C, 12 hours), followed by reduction with sodium borohydride (NaBH₄). The resulting product exhibited a yield of 21.4% and a substitution degree of 64.56%. The in vitro results demonstrated that HBCOS exhibited significantly enhanced antioxidant activity compared to unmodified chitooligosaccharide (COS). At a concentration of 1000µg/ml, HBCOS showed a markedly higher reducing power (OD = 0.249 vs. 0.083) and greater hydroxyl radical scavenging efficiency (48.79% vs. 31.73%). Furthermore, HBCOS effectively protected DNA from oxidative damage induced by reactive oxygen species across a concentration range of 10-100µg/ml. These findings highlight the strong antioxidant potential of HBCOS and support its prospective application as a bio-based agent in pharmaceutical and functional food development.