芸豆肽的抗氧化活性研究

采用Sephadex-G50 凝胶柱层析分离具有强抗氧化活性的小分子芸豆肽，以VC 为对照，研究3 种肽分离组分的还原能力及对羟自由基、超氧阴离子自由基和DPPH 自由基的清除能力。结果表明：随着相对分子质量的减小和肽质量浓度的增加，其还原能力及对羟自由基、超氧阴离子自由基和DPPH 自由基的清除能力逐渐增大；小分子芸豆肽(C 组分)的还原能力低于VC；对羟自由基、超氧阴离子自由基和DPPH 自由基的半清除质量浓度分别为2.301、2.553、1.386mg/mL。该小分子肽组分的相对分子质量主要集中在100～1000，该组分疏水性氨基酸含量为36.78%，其疏水值达到364.73 kcal/mol。说明小分子肽组分的抗氧化活性与其氨基酸种类和组成、相对分子质量分布密切相关。

Antioxidant and Free Radical-scavenging Activities Bean Peptides (KBP)

Kidney bean peptides (KBP) were fractionated by gel filtration on SephadexG-50.The antioxidant and free radicalscavenging activities of three KBP fractions (Fra-A, Fra-B, Fra-C) were investigated using reducing power and 1,1-diphenyl- 2-pycrylhydrazyl (DPPH)/superoxide/hydroxyl radical-scavenging assay. The reducing power activity of Fra-C (RP50 2.263 mg/mL) was lower than that of ascorbic acid (RP50 0.828 mg/mL). Fra-C showed the strongest scavenging activity against DPPH, superoxideanion and hydroxyl radicals. The radical-scavenging effect was in a dose-dependent manner and the EC50 values for DPPH, superoxide and hydroxyl radicals were found to be 2.301, 2.553 mg/mL and 1.386 mg/mL, respectively. The amino acid analysis showed that Fra-C had a hydrophobic amino acid content of 36.78% and a hydrophobicity of 364.73 kcal/mol.The molecular weight distribution of Fra-C was found to mainly vary from 100 to 1000. The antioxidant activity of Fra-C is clearly related to the amino acid composition, the content of THAA and the molecular mass.