## 3 Results and Discussion
### Polyphenolic Profile by UPLC-ESI-MS Analysis  
The UPLC-ESI-MS analysis described in the Materials and Methods section, allowed identifying 34 plophenolic compounds, including four parados, five gingerols, two methylgingerols, three shogaols, three gingerdiols, three dihydrogeniones, three acetoxygingerols, one methylacetoxygingerol, one methylacetoxygingerdiol, four diacetoxygingerdiols, and four methyldiacetoxygingerdiols. Table S1 summarizes the analysis results for these compounds and Figure 1 shows the chromatograms for the 34 secondary metabolites. The compounds identified had in common a 1, 3, 4-trisubstituted benzene ring consisting of a 3-methoxy group, a 4-hydroxyl or 4-methoxy group, and an unbranched alkyl chain. Most compounds in this study present a homologous series that leads to an increase in hydrophobicity due to greater alkyl chain length, which further supports the observed higher retention times [11]. The first group is constituted by parados, a series of compounds with a ketone at C-3 of the alkyl chain, as shown in Figure 2. In addition, all four compounds demonstrated consistent fragmentation behavior according to benzylic cleavage with a product ion of m/z 137 (Figure 2) [24]. Peak 4 (Rt = 12.98 min) corresponds to 6-Paradol, providing a sodium adduct [M+Na]\({}^{+}\) at m/z 301.1882 with a molecular formula C\({}_{17}\)H\({}_{26}\)O\({}_{3}\)Na, and a pseudomolecular ion [M+H]\({}^{+}\) at m/z 279.1882 (C\({}_{17}\)H\({}_{27}\)O\({}_{3}\)). Peaks 9 (Rt = 18.19 min), 13 (Rt = 18.77 min) and 22 (Rt = 23.48 min) are tentatively assigned to 8-Paradol, 7-Paradol and 10-Paradol with their respective pseudomolecular ion [M+H]\({}^{+}\) at 307.2195 (C\({}_{19}\)H\({}_{31}\)O\({}_{3}\)), 293.2095 (C\({}_{18}\)H\({}_{29}\)O\({}_{3}\)) and 335.2509 (C\({}_{21}\)H\({}_{35}\)O\({}_{3}\)), and presenting [M+Na]\({}^{+}\) adducts at m/z 329.2185, 315.2032 and 357.2505, respectively. The second group correspond to gingerols, which are the most known pungent compounds of ginger [25], and includes peaks 1 (Rt = 8.20 min), 3 (Rt = 12.93 min), 10 (Rt = 18.23 min), 23 (Rt = 23.52 min) and 30 (Rt = 28.43 min). Peak 1, with a [M+Na]\({}^{+}\) ion at m/_z_ 289.1512 (C15H22O4 Na), was tentatively assigned to 4-gingerol. In turn, peak 3 had [M+Na]\({}^{+}\) at m/_z_ 317.1831 (C17H26O4 Na) and was assigned to 6-gingerol, while peak 10 with [M+Na]\({}^{+}\) at m/_z_ 345.2137 (C19H30O4 Na) was identified as 8-gingerol. Meanwhile, peak 23 had [M+Na]\({}^{+}\) at m/_z_ 373.2438 (C21H30O4 Na) and was assigned to 10-gingerol and finally, peak 30 with [M+Na]\({}^{+}\) at m/_z_ 401.2653 (C23H38O4 Na) was identified as 12-gingerol. All these peaks had an adduct corresponding to [M+H-H2O]\({}^{+}\) at m/_z_ 249.1518, 277.1831, 305.2136, 333.2457 and 361.2740, respectively. The fragment at m/_z_ 179 observed in gingerols (Figure 3) is produced following the path of fragmentation from dehydrated pseudomolecular ions [M+H-H2O]\({}^{+}\)[12]. This ion is decomposed into fragments at m/_z_ 177, 145 and 117 by successive losses of 2 H\({}^{+}\) (2 Da), CH3 OH (32 Da) and CO (28 Da), respectively. In turn, the formation of the fragment at m/_z_ 177 could derive directly from the dehydrated pseudomolecular ions [M+H-H2O]\({}^{+}\) by the loss of CH3-(CH2)\({}_{n}\)-CHO (_n_ = 2, 4, 6, 8 and 10 for 4-gingerol 6-gingerol, 8-gingerol, 10-gingerol and 12-gingerol, respectively) [11]. This ion, in turn, gives rise to the fragment at m/_z_ 137 due to the loss of lateral chain CHCHCH2 (40 Da). Figure 1: UHPLC QTOF-ESI MS Extracted ion chromatograms of phenolic compounds from \(Z\). _official_ rhizomes. Figure 2: Fragmentation pathway for paradol compounds 4 (_n_ = 6), 9 (_n_ = 7), 13 (_n_ = 8), 22 (_n_ = 10).