Inhibition in vitro linoleic acid peroxidation and haemolysis by caffeoyltryptophan.
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| Abstract |
Antioxidant activities of caffeoyltryptophan were investigated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging system, the superoxide anion generation system and the superoxide anion-mediated linoleic acid peroxidation system. At 10 microM, caffeoyltryptophan showed greater scavenging activity on DPPH than dl-alpha-tocopherol or ascorbic acid. DPPH radical scavenging activity of caffeoyltryptophan increased dose-dependently at concentrations ranging from 1 to 50 microM; 1 mol of caffeoyltryptophan reacted with ca 4 mol of radical. Caffeoyltryptophan caused 80% inhibition of superoxide anion generation at 50 microM. The inhibitory activity of caffeoyltryptophan was as strong as that of 5-caffeoylquinic acid. Caffeoyltryptophan inhibited the formation of conjugated diene from linoleic acid. The inhibitory activity increased in the order caffeic acid < 5-caffeoylquinic acid < caffeoyltryptophan < dl-alpha-tocopherol. Effects on the in vitro haemolysis and peroxidation of mouse erythrocytes induced by H2O2 were also examined. Caffeoyltryptophan exhibited strong inhibitory activities; Tryptophan was ineffective in these systems. These data suggest that caffeoyltryptophan may be a natural antioxidant in the human diet and, as such, may intervene in toxicological processes that are mediated by radical mechanisms.
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| Authors | M Ohnishi, H Morishita, S Toda, Y Yase, R Kido |
| Journal | Phytochemistry (Phytochemistry) Vol. 47 Issue 7 Pg. 1215-8 (Apr 1998) ISSN: 0031-9422 [Print] England |
| PMID | 9611825 (Publication Type: Journal Article) |
| Chemical References |
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