Kinetic evaluation of polyamines as radical scavengers.
To clarify whether polyamines scavenge alkyl (carbon-centered) and peroxy (oxygen-centered) radicals, we analyzed their effects on the kinetics of polymerization of methyl methacrylate (MMA) induced by 2,2'-azobisisobutyronitrile (AIBN, a R* radical) and benzoyl peroxide (BPO, a PhCOO* radical) under nearly anaerobic conditions. Stoichiometric factors (n; number of free radicals trapped by one mole of antioxidant moiety) were determined by the induction period method. The n value for polyamines (putrescine, spermidine and spermine) was 0.1-0.7, whereas that for conventional synthetic antioxidants, BHA and BHT, was about 2. These n values were not different between the AIBN and BPO systems. The n value for polyamines declined in the order spermine > spermidine > putrescine. The K(inh)/K(p) value for polyamines (20-115) was greater than that (4-7) for BHT or BHA. Radical-scavenging activity largely depends on the stoichiometric factor of antioxidants rather than their effects on initial rate of polymerization, a rate of propagation. Polyamines may scavenge alkyl or peroxy radicals derived from polyunsaturated fatty acids in biological systems.
Fujisawa
Seiichiro
S
Department of Oral Diagnosis, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan. fujisawa@dent.meikai.ac.jp
Kadoma
Yoshinori
Y
D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D001585:Benzoyl Peroxide / Q000737:chemistry; D015317:Biogenic Polyamines / Q000737:chemistry* / Q000494:pharmacology; D002083:Butylated Hydroxyanisole / Q000737:chemistry / Q000494:pharmacology; D002084:Butylated Hydroxytoluene / Q000737:chemistry / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000494:pharmacology; D007700:Kinetics; D020366:Methylmethacrylate / Q000737:chemistry; D009570:Nitriles / Q000737:chemistry; D011700:Putrescine / Q000737:chemistry / Q000494:pharmacology; D013095:Spermidine / Q000737:chemistry / Q000494:pharmacology; D013096:Spermine / Q000737:chemistry / Q000494:pharmacology
D000975:Antioxidants; D015317:Biogenic Polyamines; D016166:Free Radical Scavengers; D009570:Nitriles; D020366:Methylmethacrylate; D002084:Butylated Hydroxytoluene; D002083:Butylated Hydroxyanisole; D013096:Spermine; C004526:azobis(isobutyronitrile); D013095:Spermidine; D011700:Putrescine; D001585:Benzoyl Peroxide