Phytochemical Profile and Potential Antifungal and Phytotoxic Effects of Piper crassinervium Essential Oil and Its Pure Constituents

This study investigates the phytochemical composition and potential fungicidal and phytotoxic effects of the essential oil (EO) extracted from Piper crassinervium . Gas chromatography–mass spectrometry analysis revealed a diverse array of bioactive compounds, with myristicin (30.3%) as the predominant constituent, followed by elemicin (8.6%), epi -β-caryophyllene (7.7%), and β-caryophyllene (5.4%). The EO’s antifungal activity was evaluated in vitro against several plant pathogens, including Colletotrichum fragariae, Colletotrichum gloeosporioides, Colletotrichum acutatum, Botrytis cinerea, and Fusarium oxysporum . A bioassay-guided fractionation approach was employed to isolate the EO’s antifungal constituents, which were subsequently characterized using 1D and 2D NMR techniques. Among the isolated compounds, elemicin exhibited impressive antifungal activities against C. fragariae and B. cinerea, with IC 50 values of 13.23 and 25.88 μg/mL, respectively. Herbicidal activity was evaluated using Arabidopsis thaliana and Lemna paucicostata seed assays. Apiole and myristicin exhibited stronger inhibitory effects on A. thaliana than elemicin, with IC 50 values of 68.3, 248.9, and 360.7 μM, respectively. Apiole and myristicin also demonstrated notable inhibitory activity against L. paucicostata, with IC 50 values of 166.5 and 285.1 μM, respectively. To the best of our knowledge, this is the first study to report on the significant antifungal activity of P. crassinervium EO and its isolated pure compounds against C. fragariae and B. cinerea, as well as their moderate phytotoxic effects on A. thaliana and L. paucicostata . These findings highlight the potential of plant-derived EOs as natural alternatives to synthetic pesticides, offering promising solutions for sustainable agricultural practices and effective pest management strategies.