GC-MS based metabolic profiling of endophytic fungus isolated from Psidium guajava roots

The rising global demand for innovative therapeutics has sparked renewed interest across various scientific fields, including those focused on natural products derived from endophytic fungi. These microorganisms have demonstrated remarkable potential as sources of structurally diverse and biologically active secondary metabolites, providing an eco-friendly alternative route to direct plant extraction for novel compound discovery. In this study, an endophytic fungus was isolated from the roots of Psidium guajava L., and the metabolites produced were putatively identified using GC–MS. Fungal cultures were grown in a nutrient-rich malt extract-glucose liquid medium containing 3% malt extract and 6% glucose. The resulting ethyl acetate extract was subjected to GC–MS analysis on a system equipped with a TG-5MS capillary column (30 m × 0.25 mm × 0.25 μm) coated with 5% phenyl methyl polysiloxane, for efficient separation of volatile constituents. The analysis putatively identified fourteen major compounds from the 4.70 g extract. The compound classes include nitrogenous heterocycles, lactones, esters, phenolics, steroids, and chlorosilanes. Notably, an ester showed an uncommon structure not previously documented from Psidium guajava root endophytes. This observation highlights the potential of Psidium guajava-associated endophytic fungi as a source of chemically uncharacterized secondary metabolites.