Evaluation of Antimicrobial Effects of Different Substituted Arylpropeneones

Abstract

A series containing nine substitutes styryl 3-chloro-2-methylphenyl ketones have been synthesised by fly-ash:H2SO4 catalysed solvent free Aldol condensation between 3-chloro-2-methyl acetophenone and substituted benzaldehydes. The yields are more than 90%. These chalcones were characterised by their physical constants and spectral data. d evaluated for its antimicrobial potential using the standardized Kirby-Bauer disc diffusion method. The compounds were screened for antibacterial activity against five bacterial strains (Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli) and for antifungal activity against two fungal species (Aspergillus niger, Penicillium spp.). ntibacterial screening against five bacterial strains revealed the 4-methyl derivative as the lead compound, showing the broadest spectrum and notable activity against Staphylococcus aureus. Antifungal testing against Aspergillus niger and Penicillium species demonstrated significantly higher potency, with the same 4-methyl analogue exhibiting superior, broad-spectrum efficacy, nearly matching the standard drug miconazole against Penicillium. The study establishes clear structure-activity relationships, highlighting the critical role of the substituent's electronic nature and position. Electron-donating groups, particularly at the para position, enhanced bioactivity, while meta- versus para- substitution often dictated striking species selectivity. These results identify the 4-methyl-substituted scaffold as a promising dual-activity lead for the development of novel antimicrobial agents.