## 3 Results
### Antimicrobial Activity  
Regarding the results in antimicrobial activity, Table 5 shows the MICs of the extracts against the tested bacteria. At the highest tested concentration of 40 mg/mL, no extract from either mushroom was able to inhibit _Pseudomonas agarici_, _Pseudomonas fluorescens_, or _Pseudomonas loaasii_. These bacteria are known mushroom pathogens, which might  
Figure 3: Contribution of variables in first two components. Figure 2: A score plot of the extraction experiments in the sorting space built for the linear regression of the two first components. (AC—_A. cylindnaca_; PE—_P. ergrgii_; PO—_P. ostreatus_). Extract M1—hot extraction (1 g of mushroom dry matter (DM); 20 mL of water; 90 °C, 700 rpm, 1 h); extract M2A—room-temperature extraction (1 g of mushroom DM; 20 mL of water); extract M2B—hot extraction of residue from M2A (1 g of mushroom DM; 20 mL of water; 90 °C, 700 rpm, 1 h). be a reason to justify their resistance to these extracts [42; 43; 44]. The growth of the other seven bacteria was inhibited by at least one extract. The M2A extract from _A. cylindricalacea_ showed antimicrobial activity against a higher number of bacteria (_Bacillus cereus_, _Listeria monocytogenes_, _Salmonella enterica_, _Yersinia enterocolitica_, and _Pseudomonas aeruginosa_ at 20 mg/mL) than all other extracts, being the most promising extract to be used as a natural antimicrobial substance. On the other hand, extracts M1 and M2B from the same mushroom (_A. cylindracea_) showed the worst results regarding antimicrobial activity, since they inhibited the growth of none or only two bacteria, respectively. The highest antimicrobial activity was observed for the _P. eryngii_ M1 extract against _L. monocytogenes_ with an MIC of 2.5 mg/mL. _P. aeruginosa_ was the most susceptible bacteria since its growth was inhibited for all extracts, excluding M1 from _A. cylindtracea_, with MICs ranging from <5 to 10 mg/mL, <5 to 20 mg/mL, and 20 to 40 mg/mL in extracts from _P. ostreatus_, _P. eryngii_, and _A. cylindtracea_, respectively. The second most susceptible bacterium was _S. enterica_, since it was inhibited for all extracts, excluding the M1 and M2B extracts from _A. cylindtracea_. In other studies, the antimicrobial screening of extracts from these mushrooms varies greatly in terms of extraction methods and the choice of assay in which the antimicrobial activities are assessed. For these reasons, direct comparisons to the present results are difficult. For instance, aqueous extracts from _P. ostreatus_ showed almost no activity (3 out of 29 bacterial pathogens) at a higher concentration of 1000 mg/mL using the disk diffusion method [45]. A _P. ostreatus_ extract obtained using equal thirds of glycerol, ethanol, and distilled water showed activity against _B. cereus_ and _P. aeruginosa_ at 50 mg/mL using the well diffusion method [46]. However, an ultrasound-assisted extraction of the phenol fraction of _P. ostreatus_ using hydroalcoholic conditions revealed MICs in the \(\upmu\)g/mL range for _E. coli_, _P. aeruginosa_, _B. cereus_, and _S. aureus_[47]. Regarding _P. eryngii_, an extract obtained using a solution of 10% acetic acid in phosphate saline buffer revealed MICs of 25% (\(\
u/v\)) for _P. aeruginosa_, _E. coli_, and _S. aureus_[48]. In addition, different extracts using acetone and ethanol revealed antibacterial activity against _P. aeruginosa_, _E. coli_, and _S. aureus_ at 50 mg/mL using the disk diffusion method [49]. To the best of our knowledge, no antibacterial activity has been reported for _A. cylindtracea_ in the literature, although there are reports of antifungal activity [40; 50]. The antimicrobial activity of mushroom aqueous extracts has been associated with the presence of several bioactive molecules, namely phenolic acids, \(\upbeta\)-glucans, and lectins [1; 8].