Phenolic compounds of Phellinus spp. with antibacterial and antiviral activities.

Phellinus Quél is one of the largest genera of Hymenochaetaceae; it comprises about 220 species widely distributed on Earth. Most Phellinus species are lignicolous mushrooms that accumulate bioactive compounds. This research studied the phenolic composition of Phellinus spp. and their relationship with antibacterial and antiviral capacity. Phenolics were extracted from Phellinus badius, P. fastuosus, and P. grenadensis; their antiviral and antibacterial activities were evaluated against Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, and Escherichia coli O157: H7; and the bacteriophages MS2 and Φ- × 174. Gallic acid, chlorogenic acid, caffeic acid, epicatechin, ferulic acid, catechin, 1,3-dicaffeoylquinic acid, p-coumaric acid, and rutin were found in different proportions among Phellinus spp. Total phenolic content ranged from 96 to 209 mg GAE/g, and total flavonoids from 10 to 27 QE/g. The minimum inhibitory concentrations of P. badius, P. grenadensis, and P. fastuosus against E. coli O157: H7 were 13, 20, and 27 mg/mL, against S. enterica were 20, 30, and 15 mg/mL, and against L. monocytogenes were 10, 15, and 25 mg/mL, respectively. The phenolic content was better correlated with the antibacterial effect against E. coli O157: H7 and L. monocytogenes (r = 0.8-0.9), but not against S. enterica (r = 0.05). The antiviral activity of the extracts (0.9 mg/mL) was 29 to 41% against MS2 and 27 to 38% for Φ-X174 virus (r = 0.8-0.9). In silico analysis showed binding energy values of - 7.9 and - 4.8 kcal/mol between the identified phenolic compounds and the M and G proteins of each virus. The antibacterial and antiviral properties of Phellinus species were correlated with the phenolic content.