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

Abstract

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. The results of bioassays indicated that compound A12, having an EC50 value of 4.7μg 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, 71.4μg mL-1 ) and bismerthiazol (BT, 54.7μg mL-1 ). Compound A2, having an EC50 value of 1.1μg 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 (60.0μg mL-1 ) and BT (48.9μg 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 μg 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). Novel myricetin derivatives containing a sulfonamide moiety were synthesized and bioassay results showed that compounds A2 and A12 exhibited the best antibacterial activities. © 2019 Society of Chemical Industry.