Synthesis, Antifungal Activity, 3D-QSAR and Controlled Release on Hydrotalcite Study of Longifolene-Derived Diphenyl Ether Carboxylic Acid Compounds

Twenty-two novel longifolene-derived diphenyl ether-carboxylic acid compounds7a–7vwere synthesized from renewable biomass resources longifolene, and their structures were confirmed by FT-IR,1H NMR,13C NMR, and HRMS. The preliminary evaluation of in vitro antifungal activity displayed that compound7bpresented inhibition rates of 85.9%, 82.7%, 82.7%, and 81.4% againstAlternaria solani, Cercospora arachidicola,Rhizoctonia solani,andPhysalospora piricola, respectively, and compound7lpossessed inhibition rates of 80.7%, 80.4%, and 80.3% againstR. solani,C. arachidicola,P. piricola, respectively, exhibiting excellent and broad-spectrum antifungal activities. Besides, compounds7fand7ashowed significant antifungal activities with inhibition rates of 81.2% and 80.7% againstA.solani, respectively. Meanwhile, a reasonable and effective 3D-QSAR mode (r2= 0.996,q2= 0.572) has been established by the CoMFA method. Furthermore, the drug-loading complexes7b/MgAl-LDHwere prepared and characterized. Their pH-responsive controlled-release behavior was investigated as well. As a result, complex7b/MgAl-LDH-2exhibited excellent controlled-releasing performance in the water/ethanol (10:1, v:v) and under a pH of 5.7.Keywords:longifolene;hydrotalcite;antifungal activity;3D-QSAR;controlled-releasing