title: Oxidation rate of conjugated linoleic acid and conjugated linolenic acid is slowed by triacylglycerol esterification and alpha-tocopherol.
abstract: We have recently shown that alpha-eleostearic acid (alpha-ESA), a conjugated linolenic acid, has a stronger antitumor effect than conjugated linoleic acid (CLA), both in vitro and in vivo. In this study, the oxidative stability of alpha-ESA was examined compared with linoleic acid (LA), alpha-linolenic acid (LnA), and CLA. Thin layers of the FA (LA, 9Z,11 E-CLA, 10E,12Z-CLA, LnA, and alpha-ESA) were auto-oxidized at 37 degrees C, and the FA remaining, the absorbed oxygen volume, the lipid hydroperoxide content, and the TBARS content were determined. The oxidation rate of alpha-ESA was faster than that of the unconjugated FA and CLA (9Z, 11 E-CLA and 10E, 12Z-CLA). However, the lipid hydroperoxide and TBARS contents following alpha-ESA oxidation were low, suggesting production of only small amounts of rapid-reacting secondary oxidation products. Furthermore, the oxidative stability of conjugated FA (CLA and CLnA) in which the carboxylic acid group was esterified with triacylglycerol was greater than that of the FFA. Addition of an antioxidant (alpha-tocopherol) also increased the stability of the conjugated FA to a level similar to that of the unconjugated FA.
authors.affiliation: Food & Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tsuzuki
authors.forename: Miki
authors.initials: M
authors.lastname: Igarashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Iwata
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Yamauchi-Sato
authors.forename: Takaya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Kanehide
authors.initials: K
authors.lastname: Ogita
authors.forename: Toshihide
authors.initials: T
authors.lastname: Suzuki
authors.forename: Teruo
authors.initials: T
authors.lastname: Miyazawa
mesh_terms: D004951:Esterification; D019649:Food Industry; D007700:Kinetics; D044243:Linoleic Acids, Conjugated / Q000737:chemistry*; D008054:Lipid Peroxides / Q000032:analysis; D010084:Oxidation-Reduction; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014280:Triglycerides / Q000737:chemistry*; D017962:alpha-Linolenic Acid / Q000737:chemistry*; D024502:alpha-Tocopherol / Q000737:chemistry*
chemical_list: D044243:Linoleic Acids, Conjugated; D008054:Lipid Peroxides; D017392:Thiobarbituric Acid Reactive Substances; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D024502:alpha-Tocopherol