Study of antimicrobial and antioxidant activities of pyrrole-chalcones

Abstract

The resistance of pathogenic microorganisms to accessible antibiotics, anxiolytics, sedatives, hypnotics and anti-convulsants are rapidly forming a foremost problem worldwide. The detailed spectroscopic, DFT, antimicrobial, and antioxidant analysis of synthesized pyrrole chalcone derivatives (3a, 3c, 3h, 3i, and 5a) have been performed and interpreted. Occurring of doublet in 1H NMR spectra of (3a, 3c, 3h, 3i, and 5a) compounds in the range of δ 7.656-6.960 confirms the presence of β-vinyl (=C-H) proton and another doublet at δ 7.206-6.707 confirms the presence of α-vinyl (=C-H) proton, respectively, confirming the formation of reported products. The global electrophilicity index (ω = 5.26 eV) shows that the (3g) molecule is a strong electrophile among all the studied compound. All compounds tends to the formation of pyrazoline, oxazoline heterocyclic compounds which may have considerable pharmacological activities and material applications. The solvent-induced effects on the non-linear optical properties (NLO) were studied by using self-consistent reaction field (SCRF) method. As the solvent polarity increases, the β value have been found to increases monotonically. The compound (3a, 3c, 3g, 3h, 3i, and 5a) displayed better non-linear optical (NLO) responses than the standard p-Nitro aniline (pNA) in solvent and as well as in gas phase. 3g and 3i have high NLO values even in gas phase which can be attributed to their unsymmetrical and high non-planar structure. All studied compounds (3a, 3c, 3g, 3h, 3i, and 5a) show good antifungal and antibacterial activity against A. Niger and gram-positive bacteria B. subtilis but 3g, 3h, and 3i showed more prominent activity which can be attributed to their either substituents. Compounds 3h, 3c, 3a, and 3g showed better free radical scavenging than standard BHT, whereas 3h, 3c, 3a showed better Fe2+ ion chelating activity than standard EDTA, and better Total reductive capability than standard BHA. Thus they are suitable for both material and biological applications.