## 3 Results and Discussion
### Total Gingerol and Shogaol Contents in Z. officinal Extracts  
UPLC-DAD analysis allowed the quantification of 6-gingerol, 8-gingerol, 10-gingerol, 6-gingerdiol and 6-dehydrodingerdione, to determine the total gingerols (TG) in each sample, as well as 6-shogaol contents, while 8 and 10-shogaols were not quantifiable. The results are summarized in Table 2.  
Figure 11: Fragmentation pathway for methyl-diacetoxy-gingerdiol compounds 15 (\(n\) = 4), 24 (\(n\) = 6), 31 (\(n\) = 8), 33 (\(n\) = 10).  
Results for TG content range from 23.26 to 48.17 mg/g dry sample. One-way ANOVA followed by Tukey post hoc test indicates a significant difference (\(p<0.05\)) between samples from the Northern region and Western region, with samples from the first region presenting high TG content, while samples from the second region show low TG content. At an individual level, SR-1 rhizomes (48.17 mg/g dry sample) from the Southern region constitute the sample with higher TG content, followed by samples NR-4 (42.05 mg/g of dry sample) and NR-3 (39.59 mg/g of dry sample) from the Northern region. The lowest TG content was presented by samples WR-2 (23.26 mg/g dry sample) and WR-1 (23.52 mg/g dry sample).  
At individual singerools level, samples from the Northern region presented the highest percentage of 6-gingerol, with an average of 72% of 6-gingerol in respect to TG content, compared to the Northwestern region with 68%, the Southern region with 63% and the Western region with 61%. Regarding 8-gingerol, sample SR-1 from the Southern region showed the highest percentage of 8-gingerol, which represented 18% of the TG content, while samples from the Western region showed the lowest 8-gingerol content, with an average of 10% in respect to TG content. Samples from the Northwestern region showed the highest 10-gingerol contents, with an average 16% of TG contents.  
All samples analyzed presented a Total Gingerol (TG) content higher than 0.8% and a Total Shogaol, represented by 6-shogaol, equal or lower than 0.18%, as established by the United States Pharmacopeia (USP) [20]. Previous results for rhizomes from India reported samples with 6-gingerol contents between 1030 and 3049 \(\upmu\)g/g of fresh sample, 8-gingerol contents from 105 to 312 \(\upmu\)g/g of fresh sample and 10-gingerol contents between 105 and 425 \(\upmu\)g/g of fresh sample [26]. Samples from Costa Rica analyzed in the present work showed higher gingerol contents, with 6-gingerol content between 2401 and 4211 \(\upmu\)g/g of fresh sample, 8-gingerol content from 141 to 1165 \(\upmu\)g/g of fresh sample and 10-gingerol content between 453 and 1507 \(\upmu\)g/g of fresh sample. Samples analyzed also showed higher 6-gingerol content than a sample from China, which presented a content of 4.31 mg/g of dry material, while samples from Costa Rica presented contents ranging from 11.38 to 30.54 mg/g of dry material [27].  
Costa Rican ginger also presented higher gingerol contents than other samples from China and Malaysia [28; 29]. On the other hand, shogaol content was found to be lower than samples from Malaysia, where 6-shogaol content was between 2.20 and 7.49 mg/g of dry sample [28], while the highest 6-shogaol content found in all 12 samples analyzed in the present work was found to be 1.90 mg/g of dry sample.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Product** & **TG (mg/g) 1,2,3** & **6-gingerol** & **8-gingerol** & **10-gingerol** & **6-gingerol** & **Dehydro-6-** & **6-shogaol** \\  & **(mg/g) 1,2,3** & **(mg/g) 1,2,3** & **(mg/g) 1,2,3** & **(mg/g) 1,2,3** & **(mg/g) 1,2,3** & **(mg/g) 1,2,3** & **(mg/g) 1,2,3,4** \\ \hline NR-1 & 31.99 \({}^{\text{e.f.}}\pm\) 1.26 & 22.04 \({}^{\text{e.f.}}\pm\) 0.88 & 4.76 \({}^{\text{c.d}}\pm\) 0.12 & 3.29 \({}^{\text{f.}}\pm\) 0.20 & 1.43 \({}^{\text{e.f.}}\pm\) 0.06 & 0.47 \({}^{\text{h.}}\pm\) 0.03 & 1.11 \({}^{\text{d.}}\pm\) 0.04 \\ NR-2 & 37.75 \({}^{\text{c.d}}\pm\) 0.18 & 25.51 \({}^{\text