Alkylperoxyl radical-scavenging activity of various flavonoids and other phenolic compounds: Implications for the anti-tumor-promoter effect of vegetables

Tomohiro Sawa, Mayumi Nakao, Takaaki Akaike, Kanji Ono, Hiroshi Maeda

Research output: Contribution to journalArticlepeer-review

291 Citations (Scopus)

Abstract

We recently reported that alkylperoxyl radical (ROO·) enhanced carcinogenesis in rats treated with carcinogen (Sawa et al. Cancer Epidemiol. Biomarkers Prev. 1998, 7, 1007-1012), and the tumor promoting action of ROO· could be reduced by addition of hot-water extracts of vegetables (Maeda et al. Jpn. J. Cancer Res. 1992, 83, 923-928). Here we described the ROO·- scavenging activity of flavonoids and nonflavonoid phenolics and their role in anti-tumor-promoter effects. A model molecular species, ROO·, was generated from tert-butyl hydroperoxide (t-BuOOH) and heme iron, and the scavenging of t-BuOO· was determined by (a) bioassay based on the bactericidal action of ROO·, (b) luminol-enhanced chemiluminescence, and (c) electron spin resonance. Of 17 authentic plant phenolics tested, 9 compounds (including rutin, chlorogenic acid, vanillin, vanillic acid, neohesperidin, gallic acid, shikimic acid, rhamnetin, and kaempferol) showed remarkably high ROO·-scavenging activity. Some of them were detected and quantified in hot- water extracts of mung bean sprouts, used as the model vegetable, and their contents increased after germination, which paralleled very well to the ROO·-scavenging capacity of the vegetable extracts. Thus, a diet rich in these radical scavengers would reduce the cancer-promoting action of ROO·. Consequently, the carcinogenic potentials of oxygen-related radicals may be suppressed.

Original languageEnglish
Pages (from-to)397-402
Number of pages6
JournalJournal of Agricultural and Food Chemistry
Volume47
Issue number2
DOIs
Publication statusPublished - 1999 Feb 1
Externally publishedYes

Keywords

  • Alkylperoxyl radical
  • Anti-tumor- promoter
  • Flavonoids
  • Phenolic compounds
  • Radical scavenger

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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