Evaluation of antimicrobial effect of ganoderma formosanum water extracts toward common pathogens

The purpose of this study is to use the extracellular polysaccharides and mycelial extracts of Ganoderma formosanumby three extraction ways (liquid nitrogen freeze-thawing, autoclave, milling), to test their antibacterial activity against common pathogens (Salmonella entericaserovar Typhimurium BCRC 10747, Escherichia coli BCRC 10239, Staphylococcus aureus BCRC 10451). The results showed that the extract of G. formosanumis best divided by the liquid layer of liquid nitrogen-cell breaking, and the MIC were E. coli BCRC 10239: 2.03±0.12 mg/ml, S. aureus BCRC 10451: 1.90±0.1 mg/mL, S. Typhimurium BCRC 10747: 1.97 ±0.15 mg/mL, respectively, and all the inhibitory effects were confirmed by the 24-hour growth curves. In addition, G. formosanum also have MBC against tested pathogens (E. coli BCRC 10239: 2.96 ±0.058 mg/ml, S. aureus BCRC 10451: 2.80±0.12 mg/mL, S. Typhimurium BCRC 10747: 2.91 ±0.058 mg/mL). Besides, G. formosanumliquid \zytr significantly inhibited quorum sensing (inhibition of 94.73% purple pigment) and reduced 60.80% S. aureus BCRC 10451 biofilm synthesis at MIC concentration. There is also a tendency to inhibit quorum sensing and biofilm synthesis under the action of 1/2*MIC. ? 2021 Chinese Agricultural Chemical Society. All rights reserved.