Antibacterial and Antioxidant Activities of Fomitopsis betulina Extracts

The Birch polypore fungus (Fomitopsis betulina), a well-known brown-rot macromycete parasitizing Betula spp., is recognized as a medicinal mushroom due to its antimicrobial, antiviral, antioxidant, anti-inflammatory, anticancer, and other bioactivities. Recently, mushrooms have been explored as potential therapeutic agents in veterinary medicine and livestock farming, suggesting that F. betulina could contribute significantly to these fields.

This study aimed to evaluate the antibacterial and antioxidant activities, as well as the phenolic compounds content, in ethyl acetate extracts of 22 F. betulina strains.

The agar well diffusion method was used to assess antibacterial activity. Antioxidant activity and total phenolic content (TPC) were measured spectrophotometrically using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the Folin-Ciocalteu method, respectively.

All 22 F. betulina strains exhibited antibacterial and antioxidant activities, as well as phenolic compound content, with variations attributed to strain-specific characteristics. The fungal extracts demonstrated susceptibility against Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Zones of bacterial growth inhibition ranged from 8.0±0.0 mm to 22.5±0.5 mm. The free radical scavenging activity varied from 7.74±2.40% to 96.66±0.40%. TPC ranged from 0.01±0.00 to 8.57±0.18 mg GAE/g of dry sample.

Ethyl acetate extracts derived primarily from the mycelia of F. betulina strains were identified as particularly beneficial, with strains F. betulina 2777 and 2778 emerging as promising biotechnological producers. F. betulina mycelium has a wide potential for human use, including as feed additives for livestock and the development of veterinary therapies.