Direct synthesis, characterization, in vitro and in silico studies of simple chalcones as potential antimicrobial and antileishmanial agents

Chalcone represents a vital biosynthetic scaffold owing to its numerous
therapeutic effects. The present study was intended to synthesize
seventeen chalcone derivatives (3a-q) by direct coupling of substituted
acetophenones and benzaldehyde. The target chalcones were characterized by
spectroscopic analyses followed by their in vitro antimicrobial, and
antileishmanial investigations with reference to standard drugs. The
majority of the chalcones displayed good to excellent biological
activities. Chalcone 3q (1000 μg/mL) exhibited the most potent
antibacterial effect with its zone of inhibition values of 30, 33, and 34
mm versus Staphylococcus aureus, Escherichia coli, and Pseudomonas
aeruginosa respectively. The results also confirmed chalcone 3q to be the
most potent versus Leishmania major with the lowest IC50 value of
0.59±0.12 μg/mL. Chalcone 3i (500 μg/mL) was noticed to be the most potent
antifungal agent with its zone of inhibition being 29 mm against Candida
albicans. Computational studies of chalcones 3i and 3q supported the
preliminary in vivo results. The existence of the amino moiety and bromine
atom on ring-A and methoxy moieties on ring-B caused better biological
effects of the chalcones. In brief, the investigations reveal that
chalcones (3i and 3q) can be employed as building blocks to discover novel
antimicrobial agents.