Synthesis and Biological of Novel Myricetin Derivatives Containing 1,3,4-Oxadiazoles

A series of novel myricetin derivatives containing 1,3,4-oxadiazole moiety were designed and synthesized. Bioassays indicated that some compounds showed potential antibacterial and antiviral activities. Among them, compounds 4a, 4b, 4f and 4j demonstrated appreciable inhibitory effect against Xanthomonas axonopodis pv.citri (Xac), with half-maximal effective concentration (EC50) values of 18.5, 40.7, 26.9 and 32.4 mu g/mL, which were significantly better than commercial agent bismerthiazol (68.8 mu g/mL), compounds 4f and 4j also demonstrated appreciable inhibitory effect against Xanthomonas oryzae pv. Oryzae (Xoo) with EC50 values of 45.9 and 35.7 mu g/mL, which were better than commercial agent bismerthiazol (69.3 mu g/mL). In addition, compounds 4n demonstrated significant curative activity against TMV with EC50 value of 272.8 mu g/mL, which was better than commercial agent ningnamycin (428.8 mu g/mL), compounds 4f showed protecting activity against tobacco mosaic virus (TMV) with EC50 value of 235.6 mu g/mL, which was better than commercial agent ningnamycin (447.9 mu g/mL). Microscale thermophoresis (MST) indicated that compound 4j could bind with south rice black drawf virus P9-1.