## 3 Results and Discussion
### Polyphenolic Profile by UPLC-ESI-MS Analysis
Loss of the neutral acetyl group (60 Da), as illustrated in Figure 8, generates the fragments [M+Na-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)]\({}^{+}\) at m/z 299 for acetoxy-6-gingerol, m/z 327 for acetoxy-8-gingerol and 355 for acetoxy-10-gingerol [12]. Figure 8: Fragmentation pathway for acetoxygingerol compounds 12 (\(n\) = 6), 21 (\(n\) = 8), 29 (\(n\) = 10) and methylacetoxygingerol 16 (\(n\) = 6). Figure 6: Fragmentation pathway for gingerdiol compounds 2 (\(n\) = 6), 6 (\(n\) = 8), 17 (\(n\) = 10). Figure 7: Fragmentation pathway for dehydrogingerdione compounds 19 (\(n\) = 6), 27 (\(n\) = 8), 34 (\(n\) = 10). In addition, peak 16 (Rt = 21.18 min) with a pseudomolecular ion [M+H]\({}^{+}\) at m/z 351.2173 (C\({}_{20}\)H\({}_{31}\)O\({}_{5}\)), was tentatively assigned to methyl-acetoxy-6-gingerol, with an adduct [M+Na]\({}^{+}\) at m/z 373.2072. This peak holds an additional CH\({}_{2}\) group, thus there is an increase of 14 Da, generating a product ion at m/z 151 (Figure 8), corresponding to the methylated aromatic moiety [11]. The group of acetoxy gingerdiols holds an acetoxy group in C-5 (Figure 9). Peak 5 (Rt = 15.68 min) was tentatively assigned to 5-acetoxy-6-gingerol and peak 14 (Rt = 18.82 min) was tentatively identified as methyl-5-acetoxy-6-gingerol. Both peaks present a predominant adduct [M+Na]\({}^{+}\) at m/z 361.1989 (C\({}_{19}\)H\({}_{30}\)O\({}_{5}\)Na) and 375.2150 (C\({}_{20}\)H\({}_{32}\)O\({}_{5}\)Na) respectively, but also show adducts [M+H]\({}^{+}\) (m/z 339.2177 and 353.2322) and [M+H-H\({}_{2}\)O]\({}^{+}\) (m/z 321.2059 and 335.2222). Their fragmentation is mainly due to the loss of the acetoxy group [M+H-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)]\({}^{+}\) yielding ions at m/z 279 for peak 5 and m/z 293 for peak 14 [11]. In addition, a fragment at m/z 151 is also observed for peak 14 producing the methylated aromatic moiety (Figure 9). Diacetoxy gingerdiols correspond to gingerdiols acetylated in both hydroxyl groups at C-3 and C-5. Peaks 8 (Rt = 16.74 min), 18 (Rt = 21.57 min), 26 (Rt = 26.34 min) and 32 (Rt = 30.49 min) present predominant [M+Na]\({}^{+}\) adducts at m/z 375.1880 (C\({}_{19}\)H\({}_{28}\)O\({}_{6}\)Na), 403.2200 (C\({}_{21}\)H\({}_{32}\)O\({}_{6}\)Na), 431.2443 (C\({}_{23}\)H\({}_{36}\)O\({}_{6}\)Na), and 459.2726 (C\({}_{25}\)H\({}_{40}\)O\({}_{6}\)Na), respectively. These peaks were tentatively assigned to diacetoxy 4-gingerdiol (peak 8), diacetoxy 6-gingerdiol (peak 18), diacetoxy 8-gingerdiol (peak 26) and diacetoxy 10-gingerdiol (peak 32). Their fragmentation pattern corresponds to the loss of an acetyl group [M+H-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)]\({}^{+}\) yielding ions at m/z at 293, 321, 349 and 377. In addition, the loss of a second acetyl group [M+H-2(C\({}_{2}\)H\({}_{4}\)O\({}_{2}\))]\({}^{+}\) produces ions at m/z 233, 261, 289 and 317, respectively [25]. The fragment at m/z 137 was present for all peaks corresponding to the benzylic moiety (Figure 10). Figure 10: Fragmentation pathway for diacetoxy-gingerdiol compounds 8 (\(n\) = 4), 18 (\(n\) = 6), 26 (\(n\) = 8), 32 (\(n\) = 10). Figure 1:0 Fragmentation pathway of acetoxygingerdiol 5 (\(n\) = 6) and methyl-acetoxygingerdiol 14 (\(n\) = 6). Finally, four methylated diacetoxy-gingerdiols were identified. For instance, methyldiacetoxy-4-gingerdiol, methyldiacetoxy-6-gingerdiol, methyldiacetoxy-8-gingerdiol and methyldiacetoxy-10-gingerdiol were tentatively assigned to peaks 15 (Rt = 19.79 min), 24 (Rt = 24.51 min), 31 (Rt = 28.96 min) and 33 (Rt = 30.87 min). Their predominant adducts correspond to [M+Na]\({}^{+}\) at m/z 389.1938 (C\({}_{20}\)H\({}_{30}\)O\({}_{6}\)Na), 417.2334 (C\({}_{22}\)H\({}_{34}\)O\({}_{6}\)Na), 445.2689 (C\({}_{24}\)H\({}_{38}\)O\({}_{6}\)Na) and 473.2980 (C\({}_{26}\)H\({}_{42}\)O\({}_{6}\)Na), respectively. The fragment [M+H-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)]\({}^{+}\) is due to the loss of one acetyl group corresponding to fragments at m/z 307, 335, 363 and 391.