Extracts of the Algerian Fungus Phlegmacium herculeum: Chemical Analysis, Antioxidant, Antibacterial, and Cytotoxicity Evaluation.

This study reports the first molecularly confirmed occurrence of Phlegmacium herculeum in Algeria, identified through morphological features and ITS sequence analysis (GenBank accession: PQ133121). Phytochemical profiling revealed a diverse composition of metabolites. SPME-GC-MS analysis detected volatile aldehydes (butanal, pentanal), organic acids (butanoic, pentanoic), terpenoids (limonene, 1,8-cineole), phenolics, and long-chain alkanes. Furthermore, the macrofungus has been extracted with organic solvents, and the obtained extracts have been analyzed via NMR and GC-MS, revealing the presence of organic acids (lactic, succinic, azelaic), fatty acids (palmitic, linoleic), and phenolic acids (protocatechuic, 4-hydroxybenzoic). DPPH-based analysis indicated that the antioxidant response of the crude extracts strengthened as the dose increased, with the ethyl acetate (EtOAc) extract exhibiting the highest inhibition and lowest IC50, attributed to its rich phenolic content. The chloroform (CHCl3) extract showed moderate activity, consistent with its composition of less polar metabolites such as fatty acids and terpenoids. Antibacterial assays revealed extract-specific effects: CHCl3 strongly inhibited Staphylococcus aureus (18 mm), while EtOAc was more effective against Gram-negative strains, including Escherichia coli (18 mm) and Pseudomonas aeruginosa (13 mm). Cytotoxicity testing using Saccharomyces cerevisiae confirmed that both extracts were non-toxic, maintaining ≥90% cell viability. These findings highlight P. herculeum as a novel source of bioactive metabolites with antioxidant and antibacterial potential.