title: Selective toxicity of Catechin-a natural flavonoid towards bacteria.
abstract: Catechin is a plant polyphenol composed of epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) as diastereoisomers. Among the various classes of flavonoids, catechin was found to be the most powerful free radical scavenger, scavenging the reactive oxygen species (ROS) generated due to oxidative damage with antibacterial and anti-inflammatory activity. The toxicity of catechin towards bacteria was studied using gram-positive bacteria (B. subtilis) and gram-negative bacteria (E. coli) as model organisms and was found to be more toxic towards gram-positive bacteria. From the results, catechin was found to be beneficial as well as toxic (inhibitory) to the bacteria at a selective concentration behaving as double-edged swords with an IC50 value of 9 ppm for both the bacteria. The inhibitory mechanism of catechin was by oxidative damage through membrane permeabilization which was confirmed by the formation and treatment of bacterial liposomes. SEM images of the control and treated bacteria reveals membrane damage with morphological changes.
authors.affiliation: Council of Scientific and Industrial Research (CSIR), Chemical Laboratory, Central Leather Research Institute (CLRI), Adyar, Chennai, 600 020, India.
authors.forename: Aafreen
authors.initials: A
authors.lastname: Fathima
authors.affiliation: Council of Scientific and Industrial Research (CSIR), Chemical Laboratory, Central Leather Research Institute (CLRI), Adyar, Chennai, 600 020, India. jrrao@clri.res.in.
authors.forename: Jonnalagadda Raghava
authors.initials: JR
authors.lastname: Rao
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D059808:Polyphenols / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D059808:Polyphenols; D017382:Reactive Oxygen Species; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; C057580:gallocatechol
keywords: Bacterial models; Catechin; Liposomes