Endophytic Xylaria sp. from Syzygium myrtifolium as a novel source of cytochalasin D with antimalarial activity against Plasmodium falciparum and anticancer activity against MCF-7 cells

Endophytic fungi associated with Syzygium myrtifolium have significant potential as rapid sources of bioactive compounds for drug discovery. This study aimed to identify antimalarial and anticancer compounds from an endophytic fungal isolate Xylaria sp., associated with S. myrtifolium. The Xylaria sp. SmPdDh-4 isolate was identified using morphological characterisation and phylogenetic analysis. Metabolite profiling was performed using LC-HRMS and further confirmed by NMR spectroscopy, identifying cytochalasin D as the major compound, which was also confirmed by X-ray diffraction examination. Field-emission electron microscopy indicated that cytochalasin D crystals tend to form anisotropic aggregates with rod- or needle-like morphologies, occasionally exhibiting plate-like facets. Biological activity assays demonstrated that this compound exhibits antimalarial activity against Plasmodium falciparum and moderate cytotoxic activity against MCF-7 breast cancer cells. Molecular docking analysis revealed that cytochalasin D exhibited stable interactions and high binding affinity with several target proteins implicated in antimalarial and anticancer activities.