title: Isolation, identification and antioxidant activity of bound phenolic compounds present in rice bran.
abstract: The bound phenolic compounds in rice bran were released and extracted with ethyl acetate based on alkaline digestion. An investigation of the chemical constituents of EtOAc extract has led to the isolation of a new compound, para-hydroxy methyl benzoate glucoside (8), together with nine known compounds, cycloeucalenol cis-ferulate (1), cycloeucalenol trans-ferulate (2), trans-ferulic acid (3), trans-ferulic acid methyl ester (4), cis-ferulic acid (5), cis-ferulic acid methyl ester (6), methyl caffeate (7), vanillic aldehyde (9) and para-hydroxy benzaldehyde (10). The structures of these compounds were determined using a combination of spectroscopic methods and chemical analysis. Among the compounds isolated, compound 3, 5 and 7 exhibited strong DPPH and ABTS(+) radical scavenging activities, followed by compounds 4 and 6. Compound 1 and 2 showed potent DPPH and ABTS(+) radical scavenging activities, compound 8 displayed moderate antioxidant activity against ABTS(+) radical, whereas compound 9 and 10 showed weak antioxidant activity.
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Junnan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Peng
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Tianxing
authors.initials: T
authors.lastname: Liu
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: xzhfood@njau.edu.cn.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Xin
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D004043:Dietary Fiber; D005609:Free Radicals / Q000737:chemistry; D012275:Oryza / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry
chemical_list: D000975:Antioxidants; D004043:Dietary Fiber; D005609:Free Radicals; D010636:Phenols; D010936:Plant Extracts
keywords: Alkaline hydrolysis; Antioxidant activities; Bound phenolic compounds; Rice bran; Structural identification