Separation,Purification and Structural Identification of Antioxidant Compositions from a Biological Fermentation Preparation of Native Plant Stevia rebaudiana
Abstract: This research was to separate,purify and structurally identify the high antioxidant compositions from a fermentation preparation of a Chinese plant Stevia rebaudiana(SC3).The DPPH assay was used as an antioxidant activity monitoring parameter,and different fractions were obtained with different polar solvents such as petroleum ether,ether,ethyl acetate and normal butyl alcohol.The main antioxidant components from the highest antioxidative fractions were separated and purified by a GF254 TLC assay,and their chemical structures were further analyzed by GC-MS.The results indicated that scavenging effect of the ether fraction and ethyl acetate fraction from SC3 on DPPH radical was the highest at the concentrations of 0.006 6%,0.013 2% and 0.019 8% respectively.Four main antioxidative components C1,C2,C3,C4 were separated by ether,fraction and their scavenging effect on DPPH radical reached 24.95%,10.30%,75.12% and 77.49% respectively.The structural analysis indicated that C3 was catechol,and C4 maybe 3-isopropoxy-5-methyl-phenol.It suggests that the polyphenols might be the main constitutes in SC3 with high antioxidant activity.
2010, Vol. 36 
