Detoxification\nMechanism of Hinokitiol by Alternaria alternata and Its Application in Agricultural\nAntifungal Control

Alternaria alternata is\na common\nplant pathogen that can infect crops and reduce their production.\nIn this work, an antagonism experiment between A. alternata and the essential oil of arborvitae (Platycladus\norientalis) was performed, and it was proven that A. alternata had developed resistance to this plant-derived\nfungicide. A. alternata facilitated\nthe biotransformation of hinokitiol (<b>1</b>), the main antifungal\ncompound in the essential oil of arborvitae, into (<i>R</i>)-2-hydroxy-β-methylbenzeneethanol (<b>2</b>), which\ndoes not have antifungal activity against A. alternata. This biotransformation is an unusual ring-contraction reaction\nthat was verified to be catalyzed by P450 enzyme hydroxylation and\nBaeyer–Villiger oxidation. In addition, the P450 enzyme inhibitors\n1-aminobenzotriazole and piperonyl butoxide effectively prevented\nthe destruction of the hinokitiol structure by A. alternata, and the combined use of these P450 enzyme inhibitors significantly\nincreased the antifungal activity of hinokitiol. This work provides\na theoretical reference for the further development of botanical fungicides.