Chemical Composition, <i>in vitro</i> Antifungal Activity, Molecular Docking and Molecular Dynamics Simulation Studies of the Essential Oil of <i>Ballota hirsuta</i>

Abstract

Biologically active compounds extracted from plants, such as essential oils (EOs) have offered a promising alternative to control phytopathogens in the food industries. The present study describes the chemical composition and the antifungal activity of the EO of Ballota hirsuta aerial parts for the first time. Forty-three constituents were identified by gas chromatography (GC-FID and GC-MS), which the main ones are germacrene-D (16%), Z-phytol (7.7%), α-cadinol (7.3%) and carvacrol (6.7%). The EO's antifungal activity against two pathogenic fungi of apples, such as Botrytis cinerea and Penicillium expansum, was evaluated in vitro using poisoned food (PF) and volatile assay (VA) techniques. The minimum inhibitory concentration (MIC) of this oil was 2000 ppm against the two isolates tested when using PF technique, while, using the VA assay, the MICs were 1000 and 2000 ppm for B. cinerea and P. expansum, respectively. The production of fungal spores was completely inhibited at 1000 ppm for B. cinerea using the VA test and at 2000 ppm for both phytopathogens when using the PF technique. In addition, a molecular docking study was performed to predict the inhibitory activities of the main bioactive compounds of EO against the biosynthesis of 14 alpha-sterol demethylase enzymes (PDB ID: 1EA1). The docked complexes were tested to check their stability by a 50 ns molecular dynamics simulation.