title: Antibacterial activity of curcumin via apoptosis-like response in Escherichia coli.
abstract: Curcumin, a naturally occurring phenolic compound, has been shown to exhibit antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, etc., but the mechanism remains unclear. The present study was designed to investigate the novel antibacterial mechanism of curcumin that shows an apoptosis-like response in E. coli. We found that curcumin induces membrane damage at relatively high concentrations, but there was no effect at the minimum inhibitory concentration (MIC). At the MIC, curcumin-treated cells displayed various apoptotic markers such as reactive oxygen species (ROS) accumulation, membrane depolarization, and Ca(2+) influx. Expression of RecA protein, which mediates a bacterial apoptosis-like response, was also increased by curcumin. In order to evaluate the influence of RecA on the appearance of other apoptotic markers, phosphatidylserine (PS) exposure and DNA fragmentation were examined and compared with a RecA deletion strain (ΔRecA). These markers were detected in E. coli wild-type cells, but not in ΔRecA cells. In conclusion, our data demonstrate that curcumin induces an apoptosis-like response in E. coli that involves RecA.
authors.affiliation: School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu, 41566, Republic of Korea.
authors.forename: Dae Gyu
authors.initials: DG
authors.lastname: Yun
authors.affiliation: School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu, 41566, Republic of Korea. dglee222@knu.ac.kr.
authors.forename: Dong Gun
authors.initials: DG
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D003474:Curcumin / Q000494:pharmacology*; D053938:DNA Fragmentation; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D010718:Phosphatidylserines / Q000032:analysis; D017382:Reactive Oxygen Species; D011938:Rec A Recombinases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D011938:Rec A Recombinases; D003474:Curcumin
keywords: Apoptosis-like response; Curcumin; Escherichia coli; RecA