Synthesis, docking studies and antioxidant activity of some chalcone and aurone derivatives

Chalcones and aurones are found to possess high antioxidant activity. They are known to inhibit tyrosinase enzyme involved in synthesis of melanin. A series of substituted chalcones and aurones have been synthesized and tested for their antioxidant activity. Postulated structures of the newly synthesized compounds are in agreement with their IR, H-1 NMR and MS. The docking study of this series of compounds was performed on crystal structure of tyrosinase from Bacillus megaterium using VlifeMDS 3.0 software. Antioxidant activity data obtained from four methods, i.e., DPPH free radical scavenging assay, iron chelating assay, reducing power assay and hydrogen peroxide scavenging assay, indicate that the activity increased with dimethylamino group on position 4/4' of ring B as evident from the significant activities of SB7 and SB8 in case of chalcones and aurones, respectively. The poor activities of SB4 and SB5 in DPPH scavenging ability and reducing power assays could be because of presence of chloro group on B-ring. Furthermore, the activity is facilitated with the presence of hydroxyl group on A-ring (preferably on position 5/5') in both chalcones and aurones.