title: Photochemiluminescent detection of antiradical activity. VI. Antioxidant characteristics of human blood plasma, low density lipoprotein, serum albumin and amino acids during in vitro oxidation.
abstract: During investigation of the mechanism of therapeutic efficacy of UV (254 nm)-irradiated autologous blood, the antioxidant capacity (AC) of plasma, serum albumin, 20 amino acids, uric acid, ascorbic acid and alpha-tocopherol was measured after irradiation in vitro. AC of plasma demonstrated a biphasic time course (decrease to in a minimum (greater zero) followed by an increase). AC of uric acid, ascorbic acid and alpha-tocopherol diminished under irradiation to zero. In contrast, albumin and seven amino acids developed AC following irradiation. During the Cu(+2)-induced oxidation of low-density lipoprotein (LDL), the AC measured in a system for water-soluble substances appeared, after a lag-phase, to be comparable to that of the conjugated diene formation; AC of LDL measured in a system for lipid-soluble substances demonstrated a biphasic course. Our results suggest that: (a) the oxidized products of some amino acids and proteins acquire antiradical properties at the same time that they are being produced; (b) the biphasic character of changes of antioxidant properties of blood plasma during UV irradiation represents the overlapping of two processes: disappearing of antioxidants and acquisition of AC by (lipo)proteins; and (c) the measurement of AC of blood plasma (lipo)proteins can possibly serve to detect the existence and extent of oxidative stress in human organism.
authors.affiliation: Research Institute for Antioxidant Therapy Co., Berlin, Germany. poplew@berlin.snafu.de
authors.forename: I
authors.initials: I
authors.lastname: Popov
authors.forename: G
authors.initials: G
authors.lastname: Lewin
mesh_terms: D000596:Amino Acids / Q000097:blood* / Q000737:chemistry; D000975:Antioxidants / Q000032:analysis* / Q000378:metabolism; D001804:Blood Transfusion, Autologous; D006801:Humans; D066298:In Vitro Techniques; D008077:Lipoproteins, LDL / Q000097:blood* / Q000737:chemistry; D008163:Luminescent Measurements; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010777:Photochemistry; D010949:Plasma / Q000737:chemistry* / Q000528:radiation effects; D012709:Serum Albumin / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D008077:Lipoproteins, LDL; D012709:Serum Albumin