# Antioxidant, Antibacterial, and Cosmeceutical Potential of Four Common Edible Mushrooms
## 3 Results and Discussion
### Antibacterial Activity  
Nosocomial or hospital-acquired infections are mainly caused by ESKAPE pathogens, which include a list of six bacteria species: _Enterococcus ficetium_, _Staphylococcus aureus_, _Klebsiella pneumoniae_, _Acinetobacter baumannii_, _Pseudomonas aeruginosa_, _Enterobacter_ spp., and _Escherichia coli_[50]. Most of those pathogens are multidrug-resistant and are, therefore, a significant problem for global public health with enormous economic costs. Accordingly, there is an emerging need to find antimicrobials to combat ESKAPE pathogens and minimize their adverse effects [51]. Previously, [PERSON] et al. [21] reported the importance of mushrooms as a source of valuable antibacterial compounds. \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & **UV-DAD/VIS** & **UV-DAD/VIS** & & & & \\
**UV (nm)** & **Bands (nm)** & **Bands (nm)** & **Bands (nm)** & _A. bisporus_ & **B. edulis** & _L. edodes_ & **P. ostreatus** \\  & & **Standards** & **Samples** & & & & \\ \hline Galic acid & 254 & 229, 269 & 224, 261 & 0.032 \(\pm\) 0.001 & 0.112 \(\pm\) 0.003 & 0.103 \(\pm\) 0.002 & 0.102 \(\pm\) 0.003 \\ _p_-Hydroxybenzoic acid & 254 & 253 & 258 & 2.554 \(\pm\) 0.047 & 0.166 \(\pm\) 0.028 & 0.010 \(\pm\) 0.001 & 0.017 \(\pm\) 0.002 \\ (-)Epiglolocatechin gallate & 280 & 273 & 273 & n.d. & 0.252 \(\pm\) 0.008 & n.d. & n.d. \\ (+)-Catechin & 280 & 237, 279 & 226, 279 & 0.597 \(\pm\) 0.023 & n.d. & 0.044 \(\pm\) 0.003 & n.d. \\ Naringenin & 280 & 2268, 283, 331 sh & 224, 283, 309 sh & n.d. & n.d. & 0.220 \(\pm\) 0.001 & 0.275 \(\pm\) 0.014 \\ (-)-Galocatechin gallate & 280 & 273 & 274 & 0.061 \(\pm\) 0.027 & n.d. & n.d. & n.d. \\ \hline \end{tabular}  
* All the assays were carried out in triplicate, and the results were expressed as mean \(\pm\) standard deviation (\(n=3\)), DW, dry weight; n.d., not detected.  
\end{table} 
Table 2: Phenolic compounds identified and quantified from four edible mushrooms, expressed as ug/g DW, and respective wavelengths of maximum absorption in the visible region (\(\lambda\)max) of the standards and samples. In our work, we assessed the effect of the four extracts from _A. bisporus_, _B. edulis_, _L. edodes_, and _P. ostreatus_ against ESKAPE isolates. The MIC and MBC of each mushroom extract are shown in Table 3. The extract of _B. edulis_ was the only one that inhibited the growth of all bacterial isolates tested, with MIC values ranging from 5 to 20 mg/mL. The MBC values of the _B. edulis_ extract were similar to the MIC, except for MR _S. aureus_ (MJMC 565-A), which was 10 mg/mL, and for _E. facecium_, which showed no bactericidal activity at the highest concentration tested. The extract of _A. bisporus_ was able to inhibit the growth of all Gram-positive bacterial isolates, with MIC values ranging from 10 to 20 mg/mL. Concerning the Gram-negative isolates, the _A. bisporus_ extract inhibited the growth of three of the five species under analysis, with MICs ranging from 10 to 20 mg/mL. For the extract of _A. bisporus_, the MBC and MIC values were similar, except for _E. facecium_, which had no bactericidal effect. The extracts of _L. edodes_ and _P. ostreatus_ had virtually the same effect on the bacterial isolates tested, except for MR _S. aureus_ (MJMC 534-B) and _A. baumannii_, where _P. ostreatus_ showed no growth inhibition. For the extract of _L. edodes_, the MBC values observed were different from the MICs in _E. facecium_ and _E. aerogenes_, and in those bacterial isolates, the extract did not have a bactericidal activity. In turn, _P. ostreatus_ extract does not have a bactericidal effect on any of the bacterial isolates tested, except for _E. coli_, in which the MBC was equal to the MIC (20 mg/mL). Figure 2: HPLC-DAD chromatograms of _A. bisporus_, _B. edulis_, _L. edodes_, and _P. ostreatus_, recorded at 280 nm. According to our results, [PERSON] and co-workers [52] showed that among the methanolic extracts of _A. bisporus_, _B. edulis_, and _P. ostreatus_, the extract of _B. edulis_ was the one that displayed the best activity against _S. aureus_, _E.