Synthesis and biological evaluation of coumarin derived chalcones as potent antimicrobial and antioxidant agents

Coumarin derivatives are important biologically active compounds with anti-cancer, antimicrobial, anti-inflammatory, anti-HIV, anti-oxidant, anti-coagulant, anti-tubercular, anti-psychotic, and anti-malarial activities. Chalcones are the most common and simple class of aromatic five-membered heterocycles with anti-cancer, anti-oxidative, antibiotic, anthelmintic, anti-inflammatory, anti-hypertensive, and anti-HIV activities. Based on the above literature, an attempt was made to synthesize some new styryl coumarin derived chalcones and evaluated for antimicrobial and antioxidant activities. Acetyl 7-methyl coumarins were synthesized from 4-methyl salicylaldehyde, which on treating with various aromatic aldehydes in the presence of alkalinemethanol yielded various coumarin chalcone derivatives. These molecules on treating with various aromatic aldehydes yielded the title compounds (SCC 1-10). The synthesized title compounds were evaluated for antimicrobial and antioxidant activities. All the synthesized compounds were characterized by IR, NMR, and mass spectroscopy and screened for antimicrobial and antioxidant activities. Among the compounds SCC 1-10, compound SCC 7, 9, and 10 showed potent activity, and compounds 3, 4 and 8, showed moderately potent antibacterial activity.  Compounds SCC 3, 7, 9 showed potent and compounds 5, 6, and 8 showed moderately potent antifungal activity. Compounds SCC 3, 4, 7, and 9 showed potent antioxidant activity. From the results, it was concluded that the compounds bearing nitro and chloro group have shown prominent activity when compared to compounds without these groups. It was also confirmed that the groups in para position showed better activity when compared to the groups in ortho position. The above results establish the fact that styrylcoumarin fused with chalcone can be a rich source for exploitation.