葡萄籽原花青素聚合度与自由基清除能力关系的研究

采用DPPH·及化学发光法,研究葡萄籽原花青素不同聚合度组分的自由基清除能力。结果表明,原花青素对DPPH·的清除能力优于VC、VE及BHT,半抑制浓度分别为:原花青素1.8μg/ml、VC2.5μg/ml、VE6.3μg/ml、BHT3.5μg/ml。对O2·的清除能力优于VE而与VC相近。以质量浓度(μg/ml)表示时,原花青素对DPPH·的清除作用与聚合度无关,对HO·、O2·的清除能力随着聚合度的升高而下降。但以摩尔浓度(μmol/L)表示时,原花青素的自由基清除能力基本上随着聚合度的增加而提高。原花青素的抗氧化和自由基清除能力可能与所处的溶剂环境有关,水相体系中原花青素分子中单位酚羟基的活性随着聚合度的增加而下降。

Study on Relationship Between Degree of Polymerization and Radical Scavenging Capacity of Grape Seed Procyanidins

DPPH·and two chemical irritant light reactions were used for comparing the radical scavenging capacity of grape seed procyanidin fractions with different degree of polymerization(DP). Results showed that the DPPH· scavenging capacity of procyanidins was higher than VC, VE and BHT, with IC50 being 1.8, 2.5, 6.3, 3.5μg/ml respectively. For O·2, the scavenging ability of procyanidins was higher than VE and similar to VC. When compared on base of mass concentration, fractions with different DP has almost the same DPPH· scavenging capacity. But for HO·and O·2, the scavenging ability of procyanidins decreased with increase of DP. When compared on base of mol concentration, procyanidins have an increasing radical scavenging capacity as the DP increase. It seems that the antioxidant activity of procyanidins were dependent on the solvent used in the reaction system. In water, the antioxidant activity of single phenolic hydroxyl in procyanidin molecule decreased as the DP increase.