title: L-tryptophan as an antioxidant in human placenta extract.
abstract: An antioxidant was purified from human placenta extract (HPE) by using gel filtration, liquid-liquid extraction, silicagel column chromatography, and HPLC. The purified antioxidant was identified to be L-tryptophan (L-Trp). L-Trp showed higher inhibitory activity than mannitol and DMSO on the Fenton reaction-induced degradation of 2-deoxy-D-ribose. L-Trp also had much higher inhibitory activity on the cytochrome P-450-dependent lipid peroxidation than the previously identified antioxidants of HPE, L-phenylalanine, L-tyrosine and uracil. On the other hand, the inhibitory effect of L-Trp on the Fenton reaction-induced protein oxidation was smaller than that of uracil. These results suggest that L-Trp is a main antioxidant of HPE of which the effect is based on the suppression of lipid peroxidation in the oxidative stress status.
authors.affiliation: Department of Health Chemistry, Hoshi University, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Togashi
authors.forename: Noriko
authors.initials: N
authors.lastname: Takahashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Fukui
mesh_terms: D000704:Analysis of Variance; D000975:Antioxidants / Q000032:analysis*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003855:Deoxyribose / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D010924:Placental Extracts / Q000737:chemistry*; D014364:Tryptophan / Q000032:analysis*
chemical_list: D000975:Antioxidants; D010924:Placental Extracts; D003855:Deoxyribose; D014364:Tryptophan