桂花乙醇萃取物的抗氧化活性及主成分结构的鉴定

Antioxidant activity and preliminary structural identification of theethanol extract of osmanthus residue

桂花富含天然抗氧化成分,在天然抗氧化剂领域具有良好的开发应用潜力。本研究以制取香料浸膏后的桂花残渣为原料,以乙醇为溶剂提取桂花中的抗氧化物质,得到桂花乙醇粗提物,并对该粗提物开展溶解性能、pH稳定性和热稳定性等理化性质分析。随后我们运用硅胶柱层析技术,对该粗提物进行极性分级,并对不同分级产物开展体外抗氧化活性的比较分析。在此基础上,进一步对具有良好抗氧化活性的分级产物开展了初步的结构鉴定,结果表明:桂花乙醇萃取物在溶解度参数大于10的溶剂中有较大的溶解度;其在中性、酸性和温度低于60℃的条件下较为稳定;此乙醇粗提物经硅胶柱层析分离可以得到3个分级产物。体外抗氧化活性评价结果表明,分级产物中组分1(Frac1)具有良好的1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除和还原能力,而组分3(Frac3)抑制亚油酸氧化的能力最强。高效液相色谱-质谱联用分析结果表明,Frac1中活性成分主要为黄酮甙类物质,而Frac3中的主要活性组分为双黄酮类物质。

Osmanthus fragrans is rich in natural antioxidants,which has great potential in the fields of natural antioxidants.In this study,the osmanthus residue after extracting the flavor extract was used as the raw material,and antioxidant substances in the residue were extracted with ethanol.The ethanol extract of osmanthus residue(EEOR)was obtained and characterized by solubility test,pH stability test and heat stability test,respectively.Subsequently,silica gel column chromatography technology was used to separate different fractions of EEOR by polarity difference,and their antioxidant activities in vitro were compared afterwards.Furthermore,the preliminary structural identification of fractions with good antioxidant activity was carried out.Results showed that EEOR had greater solubility in solvents with solubility parameters greater than 10,and it was stable and neutral,acidic pH with the temperature lower than 60℃.EEOR was separated by silica gel column chromatography to give three fractions.The results of antioxidant activity evaluation in vitro indicated that component 1(Frac1)had good 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging and reducing ability,while component 3(Frac3)had the strongest ability to inhibit the oxidation process of linoleic acid.High performance liquid chromatography-mass spectrometry analysis showed that the active components in Frac1 were mainly flavonoids,while the main active components in Frac3 were biflavonoids.