Abstract
In the previous papers, the authors reported on the results of antioxidative effects of metabolites from tryptophan (Trp) to 3-hydroxyanthranilic acid (3-OH-An. A) on the autoxidation of lard. In this paper, the authors investigated the antioxidative activities of metabolic products of several amino acids (proline, phenylalanine, sulfur-containing amino acid and threonine) and metabolites from Trp to serotonine using A.O.M. and DPPH method (1, 1-diphenyl-2-picrilhydrazil).
The results obtained were as follows;
1) 5-oxyindolacetic acid was the most effective and followed by serotonine, 5-hydroxy-L-Trp, Trp in decreasing order in the case of metabolites from Trp to serotonine.
2) In the metabolites of proline, the proline was the most effective and followed by 5-hydroxy-proline, pyruvic and glyoxylic acids in decreasing order.
3) In the metabolites of phenylalanine, the homogentisic acid showed great antioxidant activity on the autoxidation of lard and the next were 2, 5-dihydroxylphenylpyruvic acid and phenylalanine.
4) In the metabolites of sulfur-containing amino acid, the order of antioxidative activities was cysteine>homocysteine>taurine, cystine>cystathionine
5) In the metabolites of threonine, the glycine was the most effective and followed by amino-butyric acid, threonine in decreasing order.
6) When oil was heated for 5hr, antioxidative activity of homocysteine and tocopherol was de-creased, but homogentisic and 3-OH-An. A still kept the activity.
