title: Radical-scavenging activity of dietary phytophenols in combination with co-antioxidants using the induction period method.
abstract: The radical-scavenging activity of dietary phytophenols has been investigated by many researches due to their antioxidant, anti-inflammatory and anticancer property but the radical-scavenging effect of 2-phytophenol and the phytophenol:co-antioxidants, vitamin C and thiol combination under nearly anaerobic conditions still remains unknown. The radical-scavenging activity for seventeen phytophenols and for six synthetic phenols (positive controls) was investigated using the induction period method in the polymerization of methyl methacrylates (MMA) initiated by thermal decomposition of benzoyl peroxide (BPO) by monitoring differential scanning calorimetery (DSC). The k(inh) for the phytophenols was likely with the range 0.5 × 10³ M⁻¹s⁻¹-2.2 × 10³ M⁻¹s⁻¹, whereas that for synthetic phenols, hydroquinone and galvinoxyl, was with the range 7 × 10³ M⁻¹s⁻¹-8 × 10³ M⁻¹s⁻¹. Also, the additive scavenging effect of the (-)-epigallocatechin (EGC):(-)-epicatechin (EC) and the (+)-catechin:epicatechin (EC) combination was observed at 1:1 molar ratio, whereas that of the EC:quercetin combination showed the cancel (prooxidative) effect. Furthermore, the EGC:ASDB (L-ascorbyl 2,6-dibutylate) or 2-ME (2-mercaptoethanol) combination showed the prooxidative effect. Such enhancement of prooxidation in the combination may increase their toxic effects due to their cooxidation. Also, the synergic, additive or cancel effects of the flavonoid:vitamins E combination on the induction period in the BPO (a PhCOO* radical) and 2,2'-azobisisobutyronitrile (AIBN, an R* radical) systems are discussed.
authors.affiliation: Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan. y-kadoma.fm@tmd.ac.jp
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kadoma
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Fujisawa
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001585:Benzoyl Peroxide / Q000378:metabolism; D001671:Biochemistry / Q000379:methods*; D002211:Capsaicin / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D004032:Diet; D016166:Free Radical Scavengers / Q000494:pharmacology*; D008623:Mercaptoethanol / Q000494:pharmacology; D020366:Methylmethacrylate / Q000378:metabolism; D009570:Nitriles / Q000378:metabolism; D010636:Phenols / Q000494:pharmacology*; D058105:Polymerization / Q000187:drug effects; D059808:Polyphenols / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D009570:Nitriles; D010636:Phenols; D059808:Polyphenols; D020366:Methylmethacrylate; D008623:Mercaptoethanol; D002392:Catechin; C004526:azobis(isobutyronitrile); C057580:gallocatechol; D002211:Capsaicin; D001585:Benzoyl Peroxide