Antifungal Activity of Phenyl Derivative of Pyranocoumarin from Psoralea corylifolia L. Seeds by Inhibition of Acetylation Activity of Trichothecene 3-O-Acetyltransferase (Tri101)

Antifungal activity of petroleum ether extract of Psoralea corylifolia L. seed, tested against Fusarium sp. namely, Fusarium oxysporum, Fusarium moniliforme, and Fusarium graminearum, was evaluated by agar well diffusion assay. The chromatographic fractionation of the extract yielded a new phenyl derivative of pyranocoumarin (PDP). The structure of the PDP was confirmed using spectroscopic characterization (GC-MS, IR, and NMR), and a molecular mass of m/z 414 [M-2H](+) with molecular formula C(27)H(28)O(4) was obtained. The PDP had a potent antifungal activity with a minimum inhibitory concentration of 1 mg/mL against Fusarium sp. Molecular docking using Grid-Based Ligand Docking with Energetics (GLIDE, Schrodinger) was carried out with the Tri101, trichothecene 3-O-acetyltransferase, as target protein to propose a mechanism for the antifungal activity. The ligand PDP showed bifurcated hydrogen bond interaction with active site residues at TYR 413 and a single hydrogen bond interaction at ARG 402 with a docking score -7.19 and glide energy of -45.78 kcal/mol. This indicated a strong binding of the ligand with the trichothecene 3-O-acetyltransferase, preventing as a result the acetylation of the trichothecene mycotoxin and destruction of the "self-defense mechanism" of the Fusarium sp.