title: Sonodynamic action of curcumin on foodborne bacteria Bacillus cereus and Escherichia coli.
abstract: Bacterial contamination is an important cause of foodborne diseases. The present study aimed to investigate sonodynamic action of curcumin on foodborne bacteria Bacillus cereus (B. cereus) and Escherichia coli (E. coli). The uptake of curcumin was measured for optimizing the concentration incubation time before ultrasound sonication, and colony forming units (CFU) were counted after ultrasound treatment. The chromosomal DNA fragmentation of bacteria was analyzed and the effect of hypoxic condition on the antibacterial efficacy of sonodynamic action of curcumin was also assessed in this study. The results showed that the maximum uptake of curcumin in B. cereus and E. coli occurred in 50min after curcumin incubation. Curcumin had sonodynamic bactericidal activity in a curcumin dose-dependent manner, and 5.6-log reduction in CFU of B. cereus was observed after curcumin treatment (2.0μM), however, only 2-log reduction in CFU of E. coli after 40μM curcumin treatment. No significant change in chromosomal DNA was found after the combined treatment of curcumin and ultrasound. The survival of B. cereus and E. coli after sonodynamic treatment in hypoxic group was significantly higher than that in normal oxygen group. These findings indicated that sonodynamic action of curcumin had significant inactivation effect on foodborne bacteria, and B. cereus was more sensitive to sonodynamic treatment of curcumin than E. coli. Sonodynamic antibacterial activity of curcumin might be dependent on the oxygen environment.
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Xinna
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Microbiology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Margaret
authors.initials: M
authors.lastname: Ip
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Albert Wingnang
authors.initials: AW
authors.lastname: Leung
authors.affiliation: Shenzhen Center of Disease Control and Prevention, Shenzhen, China.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Yang
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Baoting
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Siupo
authors.initials: S
authors.lastname: Ip
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China. Electronic address: csxu@cuhk.edu.hk.
authors.forename: Chuanshan
authors.initials: C
authors.lastname: Xu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects*; D015169:Colony Count, Microbial; D003474:Curcumin / Q000494:pharmacology*; D053938:DNA Fragmentation; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000187:drug effects*; D005516:Food Microbiology; D000860:Hypoxia; D013010:Sonication
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D003474:Curcumin
keywords: Curcumin; Foodborne bacteria; Sonodynamic antibacterial chemotherapy; Sonodynamic inactivation