Antibacterial properties of wild edible and non-edible mushrooms found in Zimbabwe

Abstract

Mushrooms have been used extensively in traditional medicine as antimicrobial, antiviral and antitumor agents. Infectious diseases remain a major threat to human health, due to global antimicrobial resistance. This has led to an increase in the search for new and potent antimicrobial substances. The aim of the present study was to investigate the antimicrobial activity of the aqueous (cold and hot) and organic solvents (methanol, ethanol and acetone) extracts of ten mushroom species collected from the woodlands in Zimbabwe against common local bacterial isolates Escherichia coli, Salmonella typhi, Staphylococcus aureus and Streptococcus pneumoniae using agar disc diffusion method. The crude extracts of the mushrooms exhibited antibacterial properties to all the bacteria tested. Extracts obtained from ethanol were the most effective tested against bacteria (36.5%), followed by methanol (30.8%) and acetone (30.8%). Aqueous extracts exhibited the lowest effect on bacterial growth inhibition (1.9%), despite including the extract with the highest inhibitory activity (14 mm). The acetone extract of Cantharellus symoensii had the second highest inhibitory value of 11.5 mm followed by the methanol extract from Cantharellus miomboensis and the ethanol extracts of Ganoderma lucidum and C. symoensii with values 11.0, 10.67 and 10.0 mm, respectively. Cantharellus heinemannianus and C. symoensii had the highest effect on inhibition of bacteria as indicated by the different extracts showing high inhibitory properties ranging from 8-14 mm [15.4% (8) each] followed by G. lucidum [13.5% (7)], while Boletus edulis, Coprinus sp. and Trametes strumosa had the least [5.8% (3) each]. The positive results of screening local mushrooms for antibacterial activity forms the basis for further phytochemical studies and development of antimicrobial agents against common human bacterial and fungal infections.