Exploring the Antimicrobial and Antioxidant Potential of Endophytic Fungi Isolated from Launaea mucronata

Endophytic fungi are promising sources of bioactive secondary metabolites with potential pharmaceutical applications. This study aimed to explore the antimicrobial and antioxidant activities of endophytic fungi isolated from Launaea mucronata collected from coastal and inland desert habitats of Egypt. A total of seven fungal taxa were identified, belonging to the genera Alternaria, Fusarium, Aspergillus, and Penicillium. Tissue- and habitat-specific distributions were observed, with Fusarium oxysporum occurring in both habitats, suggesting its role as a core endophyte. Methanolic extracts of selected isolates were evaluated for antioxidant activity using the DPPH radical scavenging assay and for antimicrobial activity using the agar disk diffusion method against drug-resistant bacterial pathogens and Candida albicans. Results showed that F. oxysporum exhibited the strongest antioxidant activity (IC₅₀ = 255.29 µg L⁻¹), followed by Aspergillus flavus (IC₅₀ = 284.01 µg L⁻¹) and Penicillium chrysogenum (IC₅₀ = 330.04 µg L⁻¹), although all were less potent than ascorbic acid (IC₅₀ = 198.35 µg L⁻¹). Antimicrobial screening revealed that F. oxysporum had the broadest inhibitory spectrum, particularly against Bacillus cereus (16.8 mm) and Escherichia coli (12.5 mm), while A. flavus showed the strongest antifungal activity against Candida albicans (17.2 mm). Gram-positive bacteria were generally more susceptible than Gram-negative strains. The findings highlight the ecological and biotechnological significance of endophytic fungi associated with L. mucronata, suggesting their potential as sources of novel antimicrobial and antioxidant agents