## 3 Results
### Antibacterial Activity of Mango By-Products
#### 3.2.2 Staphylococcus  
The agar diffusion assay indicated that all extracts (from peel and seed) had an inhibition effect against all the tested species. Nevertheless, the antimicrobial activity of the extracts (inhibition halo) on the different bacterial species tested was diverse. Furthermore, the extraction process and the cultivar affected the antibacterial activity of the obtained extracts. The peel extracts of process B showed higher antibacterial activity (1.5 times on average) than the extracts obtained by process A, and the Sensation cultivar (peel and seed extracts) showed (in most cases) higher antibacterial activity. The quantitative analysis of the antibacterial activity (MIC and MBC) was determined against 10 species of _Staphylococcus_ (Table 3). The MIC values ranged from 1 to 240 mg GAE/mL and the MBCs from 1 to 240 mg GAE/mL, except for _S. Iugdunensis_ (more resistant to some extracts). Taking into account the MIC values in peel extracts, two arbitrary groups can be defined: Group I, species with MICs \(\leq\) 5 mg GAE/mL, and Group II, species with MICs \(\geq\) 5 mg GAE/mL (Table 3). \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Species** & **Isolate Code** & **Flavonoids** & **Xanthones** & **Gallates** & **Ellagic Acid** & **Total** **Phenol** \\  & & & & **Gallotannins** & **Derivatives** & **Compounds** \\ \hline \hline \multicolumn{1}{c}{_Gluconobacter_} & & & & & & \\ \hline \hline \multicolumn{1}{c}{_G. japonicus_} & Gj1-P37 & 0.5578 & 0.13 & 0.2191 & \(-\)0.1594 & 0.5578 \\ \hline \hline \multicolumn{1}{c}{_G. japonicus_} & Gj3-L259 & 0.5578 & 0.13 & 0.2191 & \(-\)0.1594 & 0.5578 \\ \hline \multicolumn{1}{c}{_G. japonicus_} & Gj2-P92 & 0.4781 & \(-\)0.2445 & 0.1394 & 0 & 0.3984 \\ \hline \multicolumn{1}{c}{_Staphylococcus_} & & & & & & \\ \hline \hline \multicolumn{1}{c}{_S. arlettae_} & \begin{tabular}{c} NRRL \\ B-14764 \\ \end{tabular} & 0.414 & \(-\)0.1622 & \(-\)0.1035 & 0.6211 & 0.5175 \\ \hline \multicolumn{1}{c}{_S. equorum_ subsp.} & \begin{tabular}{c} NRRL \\ B-14765 \\ \end{tabular} & 0.414 & \(-\)0.1622 & \(-\)0.1035 & 0.6211 & 0.5175 \\ \hline \multicolumn{1}{c}{_S. carnosus_ subsp.} & \begin{tabular}{c} NRRL \\ B-14760 \\ \end{tabular} & 0.1369 & 0.3575 & \(-\)0.4108 & 0.5477 & 0.1369 \\ \hline \multicolumn{1}{c}{_S. xylosus_} & \begin{tabular}{c} NRRL \\ B-14776 \\ \end{tabular} & 0.1369 & 0.3575 & \(-\)0.4108 & 0.5477 & 0.1369 \\ \hline \multicolumn{1}{c}{_S. sciuri_ subsp. _sciuri_} & \begin{tabular}{c} NRRL \\ B-14767 \\ \end{tabular} & 0.1369 & 0.3575 & \(-\)0.4108 & 0.5477 & 0.1369 \\ \hline \multicolumn{1}{c}{_S. gallinarum_} & \
\begin{tabular}{c} NRRL \\ B-14763 \\ \end{tabular} & 0.3651 & 0.0953 & \(-\)0.2739 & 0.5477 & 0.4564 \\ \hline \multicolumn{1}{c}{_S. colnii_ subsp. _colnii_} &
\begin{tabular}{c} NRRL \\ B-14756 \\ \end{tabular} & 0.6739 & \(-\)0.4167 & 0.7625 * & \(-\)0.5763 & 0.6739 \\ \hline \multicolumn{1}{c}{_S. lugdunensis_} & 99705-65 & \(-\)0.0791 & \(-\)0.2615 & 0.4480 & \(-\)0.4216 & \(-\)0.0264 \\ \hline \multicolumn{1}{c}{_S. aureus_} & 11923-76 & 0.4099 & \(-\)0.0973 & 0.4845 & \(-\)0.5963 & 0.4099 \\ \hline \multicolumn{1}{c}{_Pseudomonas aeruginosa_} & ATCC 27853 & \(-\)0.8216 * & 0.4767 & \(-\)0.8216 * & 0.4564 & \(-\)0.8216 * \\ \hline \multicolumn{1}{c}{_Klebsiella pneumoniae_} & ATCC 13883 & \(-\)0.2739 & 0.286 & \(-\)0.7303 * & 0.4564 & \(-\)0.3651 \\ \hline \hline \end{tabular}  
* Indicates significant correlation at \(p<\) 0.05.  
\end{table} 
Table 2: _Cont._In peel extracts, no differences were observed between the MICs of both extraction processes (A and B) in the Gomera-3 and Sensation cultivars; however, in cultivar Keitt, the results were different: five bacteria species of Group I presented lower MICs with extraction process B, and three species of Group II presented lower MICs with process A. On the other hand, the extracts obtained with process A showed no differences between cultivars in the bacterial species of Group I, while in Group II, the cultivar affected the MIC values (except _S. aureus_ NRRL B-767).