海地瓜多肽分离及抗氧化活性研究

Separation and Antioxidant Activity Evaluation of Acaudina molpadioides Peptide

摘要:

本文检测评价海地瓜体壁干粉及多肽氨基酸组成，通过超滤膜分级过滤技术及层析色谱分离技术分级分离海地瓜酶解多肽，采用生化水平及细胞水平抗氧化活性分析方法研究海地瓜多肽抗氧化活性特征。研究显示，海地瓜体壁干粉及酶解多肽氨基酸含量丰富，检测的19种氨基酸总量分别占样品干重的63.06%及82.90%；其中，必需氨基酸含量分别为10.87%及15.60%。海地瓜酶解多肽小分子肽（<3 kDa）含量最高，达到43.9%；其次是分子量为3 k~10 kDa的多肽，含量为36.8%；而>10 kDa的多肽含量最低，仅为19.3%。三种海地瓜多肽中，小分子多肽（<3 kDa）抗氧化活性最高，ABTS法及FRAP法检测的TEAC值分别为0.61±0.03 mmol Trolox/g及0.32±0.02 mmol Trolox/g。海地瓜多肽明显增强HepG-2及HEK293细胞抗H2O2氧化损伤能力，且小分子多肽（<3 kDa）活性高于其他组分；G-25层析分离海地瓜小分子多肽（<3 kDa），形成6个主要吸收峰，对其样品抗氧化分析结果显示第5峰多肽样品抗氧化活性最高。

Abstract:

Amino acid composition of body wall powder and hydrolytic peptide from Acaudina molpadioides (A. molpadioides) was analyzed and in vitro antioxidant activities of peptide separated from the hydrolytic fractionations were detected. The total oxidant activity of A. molpadioides hydrolytic peptide was evaluated. Results showed the both body wall and hydrolytic peptide contained 19 kinds of amino acids, which were occupied 63.06% and 82.90% of sample dry weight, respectively. Among which, the essential amino acid content were 10.87% and 15.60%, respectively. Three compositions with different molecular weight were separated from hydrolytic peptide by ultrafiltration. The small peptides (<3 kDa) took over the highest level (43.9%) , followed by 3k-10kDa molecular weight peptides(36.8%), and the polypeptide above 10kDa was the minimum (19.3%). The ABTS and FRAP assays showed that compared to other compositions, the antioxidant activity of small peptides (<3 kDa) was the highest, the TEAC value was 0.61 ± 0.03 mmol Trolox/g and 0.32 ± 0.02 mmol Trolox/g, respectively. The result of cell culture experiments displayed that the three compositions from A. molpadioides hydrolytic peptide significantly enhanced the ability of HEK293 and HepG-2 cells against H2O2 oxidative damage. The small peptides (<3 kDa) appeared to be more active than the other components. Six major peaks in the small peptide composition were observed by glucose gel separation with G-25, and the highest antioxidant activity peptide was detected in the sample of the 5th fraction.