Bactericidal action of photo-irradiated aqueous extracts from the residue of crushed grapes from winemaking

Mana Tsukada, Hong Sheng, Mika Tada, Takayuki Mokudai, Satomi Oizumi, Toshiaki Kamachi, Yoshimi Niwano

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Our previous studies revealed that photo-irradiation of polyphenols could exert bactericidal action via reactive oxygen species (ROS). In the present study, the photo-irradiation-induced bactericidal activity of the aqueous extract from the residue of crushed grapes from winemaking was investigated in relation to ROS formation. Staphylococcus aureus suspended in the extract was irradiated with LED light at 400 nm. This solution killed the bacteria, and a 3-4 log and a >5-log reduction of the viable counts were observed within 10 and 20 min, respectively. LED light irradiation alone also killed the bacteria, but the viable counts were 2-4 log higher than those of the photo-irradiated extract. In contrast, almost no change occurred in the suspension without LED irradiation. When hydroxyl radical scavengers were added to the suspension, the bactericidal effect of the photo-irradiated extract was attenuated. Furthermore, electron spin resonance analysis demonstrated that hydroxyl radicals were generated by the photo-irradiation of the extract. The present study suggests that polyphenolic compounds in the extract exert bactericidal activity via hydroxyl radical formation upon photo-irradiation.

Original languageEnglish
Pages (from-to)113-121
Number of pages9
JournalBiocontrol Science
Issue number2
Publication statusPublished - 2016


  • Bactericidal action
  • Extract from residue of winemaking
  • Hydrogen peroxide
  • Hydroxyl radical
  • Photo-oxidation of polyphenols

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Public Health, Environmental and Occupational Health


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