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 mM 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 mM (1.315±0.75 %), with its highest haemolytic activity (47.806±2.32 %) observed at a concentration of 2.9 mM.

Crystal structure of 4-amino-1-(4-methylbenzyl)pyridinium bromide

“…Literature information revealed that the use of 4-aminopyridine had reduced chronic pain and spasticity in spinal cord injured patients (Hansebout et al, 1996). The crystal structures of a large number of pyridinium derivatives have been reported (Seethalakshmi et al, 2006;Sundar et al, 2006a,b,c) and their antimicrobial activities have also been reported (Ilangovan et al, 2012;Sundararaman et al, 2013).…”

“…For the pharmacological activity of 4-aminopyridine compounds, see: Hansebout & Blight (1996); Kumar & Rao (2005). For the antimicrobial activity of 4-aminopyridine compounds, see: Ilangovan et al (2012); Sundararaman et al (2013). For the crystal structures of related compounds, see: Seethalakshmi et al (2006); Sundar et al (2006a,b,c Symmetry codes: (i) Àx þ 1; Ày; Àz þ 1; (ii) x þ 1 2 ; Ày þ 1 2 ; Àz þ 1; (iii) Àx; Ày; Àz þ 1; (iv) x À 1 2 ; y; Àz À 1 2 .…”

Crystal structure of 3-amino-1-propylpyridinium bromide

“…Aminopyridinium and 1-alkyl-aminopyridinium salts display a wide range of antimicrobial activity (Sundararaman et al, 2013;Ilangovan et al, 2012). They have found many applications such as surfactants (Gama et al, 1981), ionic liquids (Muldoon et al, 2010;Petkovic et al, 2011), liquid-crystal display mediums (Ezaki & Kokeguchi, 2006), ionic crystals for second-order non-linear optics (Anwar et al, 2001), phasetransfer catalysts in organic transformations (Kupetis et al, 2002) and additives for protein refolding processes (Yamamoto et al, 2011).…”

Synthesis of N-Heterocyclic Analogues of 28-O-Methyl Betulinate, and Their Antibacterial and Antifungal Properties

“…and some coenzymes. In studies of N-heterocycles, quaternary ammonium compounds and their reduction products-1,2,5,6-tetrahydropyridines-are of particular interest as they can act as membrane-active substances exhibiting antitumor and antimicrobial properties [2,3].…”