Isolation of Bioactive Metabolites from Fusarium fujikuroi: GC-MS Profiling and Bioactivity Assessment

In the present study, the endophytic fungus Fusarium fujikuroi was isolated from the medicinal plant Debregeasia salicifolia and cultivated for the extraction of bioactive metabolites. The crude extract was fractionated via gravity column chromatography using solvents of increasing polarity (n-hexane, n-hexane/chloroform 1:1 v/v, chloroform, ethyl acetate, and methanol) to isolate bioactive compounds. The antimicrobial activity of these fractions was evaluated against pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). Most extracts exhibited significant antimicrobial activity, with the n-hexane/chloroform fraction (HCF) showing the highest efficacy (18 mm inhibition zone), followed by the n-hexane fraction while Ciprofloxacin was used as a positive control. Fractions were tested in triplicate; antibacterial activities (p < 0.05) were highest in the HCF. Bioactive compounds from the most potent fractions were further purified and analyzed using gas chromatography-mass spectrometry (GC-MS). The GC-MS profiling revealed the presence of diverse bioactive metabolites, including polycyclic aromatic hydrocarbons (PAHs), phenols, and fatty acids. Notably, several of these compounds have not been previously reported in Fusarium fujikuroi, highlighting the potential for novel antimicrobial agents from this endophytic strain. In silico toxicity prediction using the ProTox-II tool indicated that the major compounds possess low to moderate toxicity profiles, supporting their potential safety for further biological evaluation.