Design, synthesis and antibacterial activities against Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. Citri and Ralstonia solanacearum of novel myricetin derivatives containing sulfonamide moiety.

BACKGROUND Myricetin and sulfonamide derivatives exhibited a wide variety of biological activity. In order to develop highly bioactive molecules, novel myricetin derivatives containing sulfonamide moiety were synthesized and antibacterial activities were investigated. RESULTS The results of bioassays indicated that compound A12, having an EC50 value of 4.7 mu g mL(-1), exhibited the best in vitro antibacterial activities against Xanthomonas oryzae pv. oryzae (X. oryzae pv. o.); EC50 values for this compound were even better than those of thiodiazole-copper (TC, 71.4 mu g mL(-1)) and bismerthiazol (BT, 54.7 mu g mL(-1)). Compound A2, having an EC50 value of 1.1 mu g mL(-1), exhibited the best in vitro antibacterial activities against Xanthomonas axonopodis pv. citri (X. axonopodis pv. c); values were notably better than those of TC (60.0 mu g mL(-1)) and BT (48.9 mu g mL(-1)). Scanning electron microscopy analysis indicated that compounds A2 and A12 caused the cell membranes of X. axonopodis pv. c and X. oryzae pv. o. to break or deform, respectively. When the concentration of compound A12 was 100 mu g mL(-1), the effective curative activity against bacterial leaf blight of rice was 44.2% in vivo and the effective protection activity was 58.2% in vivo, results that were both better than values for TC (18.9 and 21.4%, respectively) and BT (12.5 and 12.5%, respectively). CONCLUSION Novel myricetin derivatives containing a sulfonamide moiety were synthesized and bioassay results showed that compounds A2 and A12 exhibited the best antibacterial activities. (c) 2019 Society of Chemical Industry