摘要
目的:测定黄瓜中总糖含量,分离制备黄瓜多糖并测定其糖醛酸含量、单糖组成以及评价其体外抗氧化活性。方法:采用苯酚-硫酸法测定黄瓜提取物中的总糖含量;用硫酸-咔唑法测定黄瓜多糖中的糖醛酸含量;采用1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化高效液相色谱(HPLC)分析单糖组成;并在体外抗氧化评价体系研究黄瓜多糖对DPPH自由基、超氧阴离子自由基(O-2.)和羟自由基(.OH)的清除活性以及总还原力(TRP)。结果表明:黄瓜多糖的总糖含量为63.5%,糖醛酸含量为10.6%。HPLC分析表明:黄瓜多糖由D-甘露糖、L-鼠李糖、D-葡萄糖醛酸、D-半乳糖醛酸、D-葡萄糖、D-木糖、D-半乳糖、L-阿拉伯糖等8种单糖组成,物质的量比为4.08:2.78:1.00:5.82:6.07:2.78:8.48:6.58。黄瓜多糖有明显的抗氧化活性,在质量浓度为20mg/mL时,对DPPH自由基、O-2.、.OH的清除率分别为92.31%、83.57%和77.59%,并发现其有明显的还原能力。结论:黄瓜多糖是一种典型的杂多糖,具有较强的抗氧化活性。
Objective: To determine total carbohydrate content in cucumber,isolate polysaccharides from it and analyze uronic acid content,monosaccharide composition and in vitro antioxidant activity of extracts obtained.Methods: Phenol-sulfuric acid and sulfuric acid-carbazole methods were employed to evaluate total carbohydrate content and uronic acid content,respectively.In addition,high performance liquid chromatography(HPLC) based on pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone(PMP) was employed to analyze the monosaccharide composition of cucumber polysaccharides.Moreover,the scavenging activity of cucumber polysaccharides against 1,1-diphenyl-2-picrylhydrazyl(DPPH),superoxide anion(O2-·) and hydroxyl(·OH) free radicals and total reducing power(TRP) of cucumber polysaccharides were evaluated in vitro.Results: The total carbohydrate and uronic acid contents in cucumber polysaccharides were 63.5% and 10.6%,respectively.The monosaccharide composition of cucumber polysaccharides was made up of D-mannose(Man),L-rhamnose(Rha),D-glucuronic acid(GlcUA),D-galacturonic acid(GalUA),D-glucose(Glc),D-xylose(Xyl),D-galactose(Gal),L-arabinose(Ara) with a molar ratio of 4.08:2.78:1.00:5.82:6.07:2.78:8.48:6.58.Cucumber polysaccharides revealed high antioxidant activity,and the scavenging rates at the concentration of 20 mg/mL against DPPH,superoxide anion and hydroxyl free radicals were 92.31%,83.57% and 77.59%,respectively.Moreover,cucumber polysaccharides also exhibited strong reducing power.Conclusion: Cucumber polysaccharides are typically heteropolysaccharides with stronger antioxidant activity.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2011年第19期70-74,共5页
Food Science
基金
国家自然科学基金项目(30972054
20802091
31171678)
关键词
黄瓜
多糖
单糖组成
自由基
体外抗氧化活性
cucumber
polysaccharide
monosaccharide composition
free radical
antioxidant activity in vitro