Tamarix aphylla is a Saudi herb, which possesses antimicrobial properties and potentially introduces a solution to the subsequent dilemma caused by agrochemicals and antifungal misuse. The current study aimed to assess the fungicidal properties of water and ethanolic extracts of T. aphylla leaves against Macrophomina phaseolina, Curvularia spicifera, and Fusarium spp. The chemical composition of T. aphylla was evaluated by gas chromatography/mass spectrometry technique (GC−MS) and Fourier-transform infrared spectroscopy (FTIR). The antifungal assay assessed the fungal growth inhibition using the poisoned food technique. Scanning and transmission electron microscopy (SEM and TEM) were used to evaluate the structural changes induced in the fungal species post-treatment by T. aphylla. FTIR and GC−MS analysis revealed that T. aphylla extracts were rich in aromatic and volatile compounds, such as Benzeneselenol, Gibberellic acid, and Triaziquone, which proved multiple antifungal properties. The results showed significant inhibition in the growth of all species (p < 0.05) except for F. moniliforme, where the water extract induced the highest mycelial growth inhibition at the dose of 30%. The highest inhibition was for M. phaseolina treated with the water extract (36.25 ± 1.06 mm, p < 0.001) and C. spicifera, treated with the ethanolic extract (27.25 ± 1.77 mm, p < 0.05), as compared to the untreated control and the positive control of Ridomol. SEM and TEM revealed some ultrastructural changes within the fungal growth of treated M. phaseolina, which included the thickening and mild rupture of mycelia. Those findings suggested the robust antifungal properties of T. aphylla against some filamentous fungi. The phenolic composition illustrated the potential fungicidal properties of T. aphylla. Additional studies are required to focus on more antimicrobial properties of T. aphylla against other species, particularly those that might benefit the medical field.
Keywords: Fourier-transform infrared spectroscopy; Tamarix aphylla; ethanolic and water extracts; filamentous fungi; fungicidal properties; gas chromatography/mass spectrometry technique; scanning and transmission electron microscopy.