title: Carvacrol and trans-cinnamaldehyde reduce Clostridium difficile toxin production and cytotoxicity in vitro.
abstract: Clostridium difficile is a nosocomial pathogen that causes a serious toxin-mediated enteric disease in humans. Reducing C. difficile toxin production could significantly minimize its pathogenicity and improve disease outcomes in humans. This study investigated the efficacy of two, food-grade, plant-derived compounds, namely trans-cinnamaldehyde (TC) and carvacrol (CR) in reducing C. difficile toxin production and cytotoxicity in vitro. Three hypervirulent C. difficile isolates were grown with or without the sub-inhibitory concentrations of TC or CR, and the culture supernatant and the bacterial pellet were collected for total toxin quantitation, Vero cell cytotoxicity assay and RT-qPCR analysis of toxin-encoding genes. The effect of CR and TC on a codY mutant and wild type C. difficile was also investigated. Carvacrol and TC substantially reduced C. difficile toxin production and cytotoxicity on Vero cells. The plant compounds also significantly down-regulated toxin production genes. Carvacrol and TC did not inhibit toxin production in the codY mutant of C. difficile, suggesting a potential codY-mediated anti-toxigenic mechanism of the plant compounds. The antitoxigenic concentrations of CR and TC did not inhibit the growth of beneficial gut bacteria. Our results suggest that CR and TC could potentially be used to control C. difficile, and warrant future studies in vivo.
authors.affiliation: Department of Animal Science, University of Connecticut, 3636 Horse Barn Hill Road Ext., Unit 4040, Storrs, CT 06269, USA. shaanvet@gmail.com.
authors.forename: Shankumar
authors.initials: S
authors.lastname: Mooyottu
authors.affiliation: Department of Animal Science, University of Connecticut, 3636 Horse Barn Hill Road Ext., Unit 4040, Storrs, CT 06269, USA. kollanooranup@gmail.com.
authors.forename: Anup
authors.initials: A
authors.lastname: Kollanoor-Johny
authors.affiliation: Department of Animal Science, University of Connecticut, 3636 Horse Barn Hill Road Ext., Unit 4040, Storrs, CT 06269, USA. genevieve.flock@uconn.edu.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Flock
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA. laurent.bouillaut@tufts.edu.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bouillaut
authors.affiliation: Department of Animal Science, University of Connecticut, 3636 Horse Barn Hill Road Ext., Unit 4040, Storrs, CT 06269, USA. abhinav.upadhyay@uconn.edu.
authors.forename: Abhinav
authors.initials: A
authors.lastname: Upadhyay
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA. linc.sonenshein@tufts.edu.
authors.forename: Abraham L
authors.initials: AL
authors.lastname: Sonenshein
authors.affiliation: Department of Animal Science, University of Connecticut, 3636 Horse Barn Hill Road Ext., Unit 4040, Storrs, CT 06269, USA. kumar.venkitanarayanan@uconn.edu.
authors.forename: Kumar
authors.initials: K
authors.lastname: Venkitanarayanan
mesh_terms: D000171:Acrolein / Q000031:analogs & derivatives* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000096:biosynthesis*; D016360:Clostridioides difficile / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D000081007:Cymenes; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects / Q000235:genetics; D039821:Monoterpenes / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D000081007:Cymenes; D039821:Monoterpenes; D000171:Acrolein; C073316:carvacrol; C012843:cinnamaldehyde