Abstract

Crude extracts derived from Aspergillus fumigatus and Penicillium chrysogenum, isolated from soil samples, were investigated for their antibacterial, antifungal, and cytotoxic activities. Ethyl acetate (EtoAc) and n-hexane (n-Hex) fractions of the extracts were tested against six pathogenic bacterial strains, including three gram-positive (Staphylococcus aureus, Bacillus subtilis, Streptococcus pyogenes) and three gram-negative species (Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica), as well as six fungal pathogens comprising three yeasts (Candida albicans, C. tropicalis, Rhodotorula) and three mycelial fungi (Trichophyton rubrum, Fusarium oxysporum, Microsporum canis). Cytotoxic activity was evaluated using brine shrimp lethality assay. The EtoAc fractions of both fungi demonstrated significantly stronger antimicrobial activity than their n-Hex fractions. The EtoAc fraction of A. fumigatus exhibited pronounced antibacterial effects, with S. aureus showing the highest susceptibility (58 mm inhibition zone at 500 µg/mL), followed by B. subtilis (48 mm) and S. pyogenes (45 mm). Gram-negative bacteria displayed moderate susceptibility, with S. enterica (35 mm) and E. coli (30 mm) being inhibited, while P. aeruginosa exhibited minimal response (20 mm). The n-Hex fraction showed reduced efficacy, with S. enterica (40 mm) being the most susceptible. For antifungal activity, the EtoAc fraction of A. fumigatus demonstrated robust inhibition, particularly against M. canis (60.5%) and T. rubrum (54%), while Rhodotorula was the most susceptible yeast (52%). The EtoAc fraction of P. chrysogenum displayed exceptional antifungal potential, with maximum inhibition against T. rubrum (70%) and M. canis (63.5%). The n-Hex fractions of both fungi exhibited limited antifungal activity at higher concentrations. Cytotoxicity assays revealed dose-dependent effects, with the EtoAc fraction of A. fumigatus inducing mortality rates of 3.33%, 46.66%, and 71.6% at 10, 100, and 1000 µg/mL, respectively. The n-Hex fraction exhibited maximum lethality of 53.33% at 1000 µg/mL. Similarly, the EtoAc fraction of P. chrysogenum displayed moderate cytotoxicity (46.66% at 1000 µg/mL), while its n-Hex fraction exhibited the highest lethality (83.33%).

Keywords: Artemia salina, Bioassay screening, Candida, Microsporum, Secondary metabolites.