Studies On Bound Chemical Components And Their Antioxidant Activity Of Wheat Bran

Wheat bran is a byproduct produced in the process of wheat milling,and contains a variety of active compositions,such as flavonoids,phenolic acid,cerebroside,polyphenol etc.Among them,some compositions have the antioxidant,anti-inflammatory,anti-cancer,lower blood pressure and fall hematic properties,and play an important role in the prevention and treatment of certain chronic diseases,such as Cardiovascular disease,atherosclerosis,coronary heart disease etc.In this study,bound compounds in wheat bran were isolated and identified.The biological activities of these compounds were evaluated preliminarily.On the basis of single factor experiments,the orthogonal test was introduced to optimize the conditions of alkaline hydrolysis for bound compounds wheat bran with the polyphenol content as the index.The optimum parameters were:digestion time of 3 h,digestion temperature of 60 ℃,the ratio of solvent to solid of 15 and alkaline concentration of 3 mol/L.Under these conditions,the content of bound phenolics was 18.28μM GAE/g.Removal the free compounds of wheat bran by organic solvent,then the remaining residue was digested under the optimum conditions,and the degradation solution was extracted by organic solvent and concentrated to give the crude extract which was rich in bound compounds.The crude extracts were separated by various column chromatography methods to obtain 11 compounds,These compounds’ structures were identified by modern spectroscopic techniques and comparison with the literature data.11 bound compounds were identified to be syringic acid(1),vanillic aldehyde(2),trans ferulic acid(3),cis ferulic acid(4),1-linoleic acid monoglycerides(5),3-ketopinoresinol(6),cis methyl 3,4,5-trimethoxycinnamate(7),trans 3,4,5-trimethoxycinnamate(8),β-sitosterol(9),methyl linoleate(10),(11)1-hydroxy-sitosterol-3-0-beta-D-glucopyranoside.The compound 6 is the first time isolating from wheat bran and the 11 is a new compound.DPPH radical scavenging method were used to evaluate the antioxidant activities of 10 compounds.The result shows that:Chemical compound 3 and chemical compound 4 has the high antioxidative activity.The IC50 was 15.19 and 16.48 μM,The left bound compounds did not have the antioxidant activity.