title: 1-alkyl-(N,N-dimethylamino)pyridinium bromides: inhibitory effect on virulence factors of Candida albicans and on the growth of bacterial pathogens.
abstract: A homologous series of 1-alkyl-(N,N-dimethylamino)pyridinium bromides, termed compounds 1-11, was synthesized and studied for antibacterial and antifungal activity. Of these, compound 8, containing a ten-carbon alkyl chain, showed maximum inhibition against all the tested bacterial strains. The highest antibacterial activity using a disc diffusion method was recorded against Mycobacterium smegmatis [zone of inhibition (ZOI): 45.75±0.25 mm], followed by Escherichia coli, Proteus mirabilis, Vibrio cholerae, Staphylococcus aureus and Salmonella typhi. In addition to antibacterial activity, compounds 3-11 displayed good inhibitory action against the human opportunistic yeast pathogens Cryptococcus neoformans and various Candida spp. The maximum ZOI was observed against Cryptococcus neoformans (51.5±0.5 mm) using compound 8, with ZOIs of 23.5±0.5, 32.0±0.0, 27.75±0.25 and 41.5±0.5 mm against Candida albicans, Candida glabrata, Candida tropicalis and Candida krusei, respectively. Furthermore, compound 8 caused inhibition of the candidal yeast-hyphae transition at a concentration of 0.29 µM and also inhibited the secretion of extracellular hydrolytic enzyme such as secreted aspartyl proteinase at subinhibitory concentrations. Compound 8 showed very little haemolytic activity at a concentration of 0.58 µM (1.315±0.75 %), with its highest haemolytic activity (47.806±2.32 %) observed at a concentration of 2.9 µM.
authors.affiliation: Department of Marine Biotechnology, Bharathidasan University, Tiruchirappalli, India.
authors.forename: Muthuraman
authors.initials: M
authors.lastname: Sundararaman
authors.affiliation: Department of Marine Biotechnology, Bharathidasan University, Tiruchirappalli, India.
authors.forename: Radhakrishnan
authors.initials: R
authors.lastname: Rajesh Kumar
authors.affiliation: School of Chemistry, Bharathidasan University, Tiruchirappalli, India.
authors.forename: Perumal
authors.initials: P
authors.lastname: Venkatesan
authors.affiliation: School of Chemistry, Bharathidasan University, Tiruchirappalli, India.
authors.forename: Andivelu
authors.initials: A
authors.lastname: Ilangovan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity; D003455:Cryptococcus neoformans / Q000187:drug effects; D024901:Drug Resistance, Multiple, Bacterial; D026141:Drug Resistance, Multiple, Fungal; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D020102:Mycobacterium smegmatis / Q000187:drug effects; D011513:Proteus mirabilis / Q000187:drug effects; D011726:Pyridinium Compounds / Q000494:pharmacology*; D012485:Salmonella typhi / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D014734:Vibrio cholerae / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D011726:Pyridinium Compounds