## 3 Results and Discussion
### The Content of Total Phenolics  
The assay with the Phenol-Ciocalteau reagent is a common and low-cost method to quantify the total level of phenolic compounds in a sample. Nevertheless, the unquestionable disadvantage of this method is the low sensitivity. It should be kept in mind that due to the low specificity of the Phenol-Ciocalteau reagent, the results of this analysis may be \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Compound** & **Retention** & **Precursor Ion** & **Product Ion 1** & **Product Ion 2** & **CP** & **CXP** \\  & **Time (min)** & **(_m/2_)** & **(_m/2_)/CE** & **(_m/2_)/CE** & **DP** & **CXP** \\ \hline
3,4-Dihydroxbenzoic acid & 3.00 & 153 & 108.9\(/-\)20 & 65.0\(/-\)30 & \(-\)30 & \(-\)11 \\ Caffe acid & 3.75 & 179 & 135.0\(/-\)22 & 107.0\(/-\)32 & \(-\)30 & \(-\)9 \\ Syringic acid & 3.80 & 197 & 181.9\(/-\)18 & 122.9\(/-\)30 & \(-\)30 & \(-\)19 \\
4-Hydroxybenzaldehyde & 4.18 & 121 & 91.9\(/-\)30 & 65.1\(/-\)32 & \(-\)30 & \(-\)11 \\ _p_-Coumaric acid & 4.33 & 163 & 119.0\(/-\)20 & 92.9\(/-\)42 & \(-\)20 & \(-\)9 \\ Ferulic acid & 4.74 & 193 & 177.9\(/-\)18 & 134\(/-\)22 & \(-\)30 & \(-\)11 \\ trans-Cinnamic-d7 acid & 7.40 & 153.9 & 110.0\(/-\)16 & - & \(-\)35 & \(-\)13 \\ trans-Cinnamic acid & 7.53 & 146.9 & 77.0\(/-\)28 & 103\(/-\)14 & -30 & \(-\)9 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mass spectrometric data for the analysis of phenolic compounds. CE—Collision Energy, DP—Declustering Potential, CXP—Collision Cell Exit Potential. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Species** & **Stems** & **Caps** & **Whole** \\ \hline _A. bisporus_ (white) & 37.9 \(\pm\) 1.1 aC & 40.2 \(\pm\) 1.4 bD & 39.7 \(\pm\) 1.0 bC \\ _A. bisporus_ (brown) & 41.7 \(\pm\) 0.6 aD & 39.3 \(\pm\) 0.3 aD & 39.9 \(\pm\) 1.3 aC \\ _L. edodes_ & 25.5 \(\pm\) 0.6 aA & 30.1 \(\pm\) 0.3 cC & 28.8 \(\pm\) 0.1 bB \\ _P. nameko_ & 37.3 \(\pm\) 0.8 cC & 21.9 \(\pm\) 0.2 aB & 26.8 \(\pm\) 0.6 bB \\ _P. eryngii_ & 40.2 \(\pm\) 0.6 bD & 38.3 \(\pm\) 0.3 aD & 39.6 \(\pm\) 0.4 abC \\ _P. ostreatus_ & 29.4 \(\pm\) 0.5 cB & 14.0 \(\pm\) 0.1 aA & 17.7 \(\pm\) 0.7 bA \\ \hline \hline \end{tabular} Mean values (\(n\) = 3) with different lowercase letters show significant differences among the parts of mushrooms belonging to the same species. Means with different capital letters indicate significant differences among the same parts belonging to various species (\(p\) < 0.05, Tukey’s test).  
\end{table} 
Table 3: Yields of ethanolic extraction (%) from dry mushroom fruiting bodies. overestimated [22]. The concentration of the total phenolics is presented in Figure 1a,b. Figure 1a shows the content of phenolics, calculated per one gram of mushroom dry weight. The quantity of phenolics in whole fruiting bodies ranged from 1.50 \(\pm\) 0.09 (_P. nameko_) to 5.57 \(\pm\) 0.19 (_A. bisporus_ (brown)). The high concentration of phenolics in ethanolic extracts obtained from the brown _A. bisporus_ supports previous findings in the literature [21]. Likewise, [PERSON] [23] reported that the content of phenolics in this mushroom was approximately twice of that of _P. ostreatus_ and amounted to \(\sim\)3 mg/g. The results showed that the brown button mushroom is approximately 21% richer in phenolics compared to the white button mushroom. This is in agreement with earlier studies where _A. bisporus_ (brown) contained \(\sim\)24% more phenolics than _A. bisporus_ (white) [24]. There was also a difference in the level of phenolics content between two _Pleurotus_ species. In the case of _P. ostreatus_ it reached 5.57 \(\pm\) 0.19 mg/g, whereas in the case of _P. eryngii_ a significantly lower quantity was found (4.61 \(\pm\) 0.14 mg/g). This observation is consistent with that of [PERSON] et al. [25], who reported that _P. ostreatus_ contained approximately 44% more phenolics compared to _P. eryngii_. With regard to the distribution of phenolics in fruiting bodies, in almost all cases caps were significantly richer in these compounds. These results match those observed in earlier studies.