title: Bactericidal Action of Photo-Irradiated Aqueous Extracts from the Residue of Crushed Grapes from Winemaking.
abstract: 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.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology.
authors.forename: Mana
authors.initials: M
authors.lastname: Tsukada
authors.forename: Hong
authors.initials: H
authors.lastname: Sheng
authors.forename: Mika
authors.initials: M
authors.lastname: Tada
authors.forename: Takayuki
authors.initials: T
authors.lastname: Mokudai
authors.forename: Satomi
authors.initials: S
authors.lastname: Oizumi
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kamachi
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Niwano
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D002853:Chromatography, Liquid; D006861:Hydrogen Peroxide; D013058:Mass Spectrometry; D050296:Microbial Viability / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species; D013211:Staphylococcus aureus / Q000187:drug effects; D027843:Vitis / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide