油茶籽粕多糖不同分子修饰产物的抗氧化活性

为比较不同修饰方法对油茶籽粕多糖抗氧化活性的影响，通过硫酸酯化、羧甲基化及乙酰化3种方法对纯化的油茶籽粕多糖(COP)进行分子修饰，以制备具有不同取代度的COP。采用体外实验法，以羟自由基(·OH)、超氧阴离子自由基(·O^-₂)及DPPH自由基(DPPH·)清除率为指标，探究COP及其分子修饰产物的抗氧化活性。结果表明：较低取代度的硫酸酯化修饰能提高COP对·OH、·O^-₂以及DPPH·的清除能力；高取代度的羧甲基化修饰能提高COP对·OH的清除能力，低取代度的羧甲基化修饰则能提高COP对DPPH·的清除能力；高取代度的乙酰化修饰COP对·OH和DPPH·的清除效果更好；羧甲基化修饰和乙酰化修饰COP均会削弱其对·O^-₂的清除能力。总之，适度的分子修饰能提高COP的抗氧化活性。

Antioxidant activity of different molecular modified products of polysaccharide from Camellia oleifera seed meal

In order to compare the effects of different modification methods on the antioxidant activity of polysaccharide from Camellia oleifera seed meal, the purified polysaccharides from Camellia oleifera seed meal (COP) was molecularly modified by sulfation, carboxymethylation and acetylation to prepare COP with different degrees of substitution. Using an in vitro test method, the antioxidant activity of COP and its molecular modification products was investigated with the scavenging rate of hydroxyl radical (·OH), superoxide anion radical (·O-2) and DPPH radical (DPPH·) as indicators. The results showed that the sulfation modification with low degree of substitution could improve the scavenging ability of COP on ·OH, ·O-2 and DPPH·. Carboxymethylation with high degree of substitution could improve the ability of COP to scavenge ·OH, and carboxymethylation with low degree of substitution could increase the ability of COP to scavenge DPPH·. The acetylated modified COP with high degree of substitution had better scavenging effect on ·OH and DPPH·. Carboxymethylation and acetylation could reduce the ability of COP to scavenge ·O-2. In conclusion, moderate molecular modification can improve the antioxidant activity of COP.