乌饭树叶提取物的化学成分与抗氧化活性研究

摘要

目的:研究不同提取方式制备得到的乌饭树鲜、干叶的提取物的化学成分和抗氧化活性.方法:对乌饭树鲜叶与干叶,分别采取水或乙醇,冷浸或回流制备提取物;DPPH、ABTS方法测定各提取物的抗氧化活性,紫外分光光度法测定其总黄酮含量,超高液相-质谱联用(UPLC-Q-TOF/MS)技术结合主成分分析方法对不同提取物的化学成分进行分析.结果:鲜叶乙醇回流提取物的总黄酮含量最高(19.48％);鲜叶水回流提取物的抗氧化活性最强;鲜叶与干叶提取物的化学成分有明显差异,鲜叶的水冷提物与乙醇冷提物的化学成分相近;干叶的水冷提物与乙醇冷提物的化学成分相近;干叶的乙醇回流提取物中化学成分最复杂,并从中鉴定出18个化合物,主要是黄酮、三萜及多酚类化合物.结论:不同提取方式所获得乌饭树叶干品、鲜品的提取物的化学成分与抗氧化活性均差异较大.%Objective:To study the chemical constituents and antioxidant activities of the extractions from fresh and dried leaves of Vaccinium bracteatum Thunb.Methods:The chemical constituents of fresh and dried leaves were extracted by water or ethanol,impregnation or reflux.The contents of total flavonoids were determined by ultraviolet spectrophotometers and the antioxidant activities were determined by DPPH and ABTS in vitro.The chemical compositions of the extracts were analyzed byultra performance liquid chromatography,time of flight mass spectroscopy (UPLC-Q-TOF/MS) and principal component analysis of base peak chromatogram.Results:The total flavonoids content of the alcohol reflux extracts was the highest (19.48％),but the antioxidant activity of the water reflux extracts was the strongest.The chemical components of fresh leaves compared with dry leaves were significantly different;chemical constituents extracted from dry leaf by cold water and cold ethanol were very close.Chemical constituents extracted from dry leaf by ethanol reflex were the most complicated ones.Eighteen compounds were identified and it mainly included flavonoids,triterpenes and polyphenols in the leaves.Conclusion:The chemical compositions and antioxidation activities of the leaves extracted by different extraction methods were quite different.