Antibacterial Potential and Chemical Composition of Shiitake Mushroom ( <i>Lentinus edodes</i> (Berk.) Sing.) Extract Against Pathogenic Bacteria

Shiitake mushrooms (<i>Lentinus edodes</i> (Berk.) Sing.) have been widely recognized for their bioactive properties, including antimicrobial activity. This study aimed to investigate the antibacterial potential and chemical composition of shiitake mushroom extracts prepared using different solvents (95% ethanol, ethyl acetate, and chloroform). The highest extraction yield (31.16%) was obtained with 95% ethanol. The antimicrobial activity of the extracts was evaluated using the paper disc diffusion method against nine pathogenic bacterial isolates, including Gram-positive (<i>Bacillus cereus</i>, <i>Staphylococcus aureus</i>, and <i>S. aureus</i> DMST20654) and Gram-negative (<i>Escherichia coli</i>, <i>E. coli</i> ATCC25922, <i>Enterobacter cloacae</i>, <i>Pseudomonas aeruginosa</i>, <i>Serratia marcescens</i>, and <i>Salmonella enterica</i> serovar <i>Typhi</i> ATCC16122) bacteria. Plates were incubated at 37°C for 24 h. All experiments were performed in triplicate. The ethyl acetate extract exhibited the strongest antibacterial activity, with the largest inhibition zone observed for <i>E. coli</i> ATCC25922 (30.00 ± 0.00 mm), followed by <i>S. enterica</i> serovar <i>Typhi</i> ATCC16122 (28.33 ± 2.00 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays confirmed the superior antibacterial potential of the ethyl acetate extract, particularly against <i>S. aureus</i> DMST20654 (MIC = 1.95 mg/mL, MBC = 31.25 mg/mL). Gas chromatography-mass spectrometry (GC-MS) analysis identified key bioactive compounds, including ergosterol (62.38%, %Prob 62.6 in the chloroform extract) and linoleic acid (28.65%, %Prob 56.5 in the ethyl acetate extract), which are known for their antimicrobial properties. The findings highlight the potential of ethyl acetate-extracted shiitake mushroom compounds as natural antibacterial agents, with applications for food preservation, nutraceuticals, and pharmaceuticals.