羟脯氨酸小肽的体外抗氧化活性

羟脯氨酸作为胶原蛋白的特征成分，其在肽序列中可使胶原衍生低聚肽对肽酶或蛋白酶产生高度抗性，口服后经过胃肠消化吸收至血液中仍能以肽的形式存在。羟脯氨酸小肽可在肠上皮细胞膜部位被完整吸收，并在血浆达到较高的水平，具有良好的吸收率和生物利用度以及更稳定、高效的生物活性。本实验以15 条羟脯氨酸小肽为研究对象，采用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)，ABTS）阳离子自由基、超氧阴离子自由基和羟自由基4 种体外方法对其抗氧化活性进行评价。结果表明：在15 条羟脯氨酸小肽中，Leu-Hyp的DPPH自由基清除率最高，为23.6%；Leu-Hyp、Ile-Hyp的ABTS阳离子自由基清除率最高，分别为57.8%和57.7%；其他小肽的DPPH自由基和ABTS阳离子自由基清除能力均较低，清除率均小于15%或不具有ABTS阳离子自由基清除能力。浓度为3 mmol/L时，15 条小肽的羟自由基和超氧阴离子自由基清除能力均较强，清除率分别可达30%～50%和60%～80%。综上，本实验所选15 条羟脯氨酸小肽均具有一定的羟自由基和超氧阴离子自由基清除能力，其中Leu-Hyp、Ile-Hyp的体外抗氧化性最好。

Antioxidant Activity in Vitro of Hydroxyproline Peptides

Hydroxyproline is a characteristic component of collagen and its existence in the peptide sequence enables collagen-derived oligopeptides to have high resistance to peptidase or protease.Oral hydroxyproline still exists in the form of peptides in the blood after gastrointestinal digestion.Small peptides containing hydroxyproline can be absorbed intact at the intestinal epithelial cell membrane and reach a high level in the plasma,indicating high absorption rate and bioavailability,and stable and potential biological activity.In this experiment,15 small peptides containing hydroxyproline were evaluated for their antioxidant activities in vitro by 1,1-diphenyl-2-trinitrophenylhydrazyl(DPPH),2,2’-azino-bis-(3-ethylbenzothiazolin-6-sulfonic acid)(ABTS)cation,superoxide anion and hydroxyl radical scavenging assays.The results showed that among the small peptides,Leu-Hyp had the highest DPPH radical scavenging activity(23.6%).Leu-Hyp and Ile-Hyp exhibited the highest ABTS cation radical scavenging rates,57.8%and 57.7%,respectively.The DPPH and ABTS cation radical scavenging capacity of the other small peptides were weak,with scavenging rates less than 15%or 0 for ABTS cation radical scavenging capacity.At a concentration of 3 mmol/L,the hydroxyl radical and superoxide anion radical scavenging capacity of all small peptides were stronger,30%-50%and 60%-80%,respectively.Collectively,the above results demonstrated that the 15 hydroxyproline-containing peptides had scavenging capacity for hydroxyl and superoxide anion radicals,and that Leu-Hyp and Ile-Hyp had the best antioxidant activity in vitro.