## 3 Results and Discussion
### Content of Total Carotenoids  
The contents of antioxidant compounds in the flowers of CA, XU, XC and PI are presented in Table 2. The red carotenoids (capsanthin and capsorubin) were the pigments with the highest presence in the flowers of XU, with values from 0.16 mg/g DW to 0.24 mg/g DW for PI, whereas the yellow carotenoids (\(\beta\)-carotene, \(\beta\)-cryptoxanthin and zeaxanthin), were only detected in XC with a minimum content of 0.02 mg/g DW. Thus far, there have been no reports of the carotenoid contents in these species of cacti; however, [PERSON] et al. [28] reported yellow carotenoids in yellow cosmos (_Cosmos sulphureus_) and spring (_Primula \(\times\) polyantha_) flowers. [PERSON] et al. [10] described higher contents of these secondary metabolites (red and yellow) in agave (_Agave salmiana_), alo (_Aloe vera_), coral tree  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Nutritional Composition (g/100 g DW)**} & \multicolumn{4}{c}{**Flowers**} \\ \cline{2-5}  & \multirow{2}{*}{**Cardón (c. _rosea_)**} & **X. ‘Ulapa’** & **X. ‘Cuaresmenño’** & **Pitaya** \\ \cline{3-5}  & & **(_C. rosea_)** & **(_O. oligacantha_)** & **(_O. matuda_)** & **(_E. cinarescens_)** \\ \hline Protein & 10.93 \(\pm\) 0.10 b & 10.50 \(\pm\) 0.15 b & 9.52 \(\pm\) 0.34 c & 13.64 \(\pm\) 0.23 a \\ Fat & 1.96 \(\pm\) 0.15 b & 2.94 \(\pm\) 0.25 a & 2.30 \(\pm\) 0.19 ab & 2.18 \(\pm\) 0.08 b \\ Carbohydrates & 67.44 \(\pm\) 0.45 a & 57.31 \(\pm\) 0.86 c & 61.20 \(\pm\) 0.63 b & 55.83 \(\pm\) 0.11 c \\ Crude fiber & 8.47 \(\pm\) 0.14 b & 11.52 \(\pm\) 0.46 a & 10.29 \(\pm\) 0.40 a & 11.52 \(\pm\) 0.12 a \\ Ash & 11.21 \(\pm\) 0.04 c & 17.73 \(\pm\) 0.10 a & 16.68 \(\pm\) 0.04 b & 16.83 \(\pm\) 0.35 b \\ Energy & 1456.22 \(\pm\) 1.45 & 1338.97 \(\pm\) 2.59 & 1356.63 \(\pm\) 1.54 & 1341.01 \(\pm\) 9.06 \\ \hline \hline \end{tabular}
\begin{tabular}{c} Cardón (_Cylindrical rupquitta rosen_), Xoconostle var. Ulapa (_Opuntia oligacantha_), Xoconostle var. Cuaresmenño rosado (_Opuntia nuttalo_), Pivas (_Echimeuscenscens_). Values represent the mean \(\pm\) standard deviation (\(n=3\)). Values with different letters in the same row indicate statistically significant differences (\(p\leq 0.05\)) according to [PERSON]’s multiple comparison test of means.  
\end{table}
Table 1: Nutritional composition of cactus flowers from Hidalgo, Mexico.  
(_Erythrina americana_) and garambullo (_Myrtillocatus geometrizans_) flowers. The contents of total carotenoids shown in Table 2 are similar to those previously reported in pansy flowers (_Viola \(\times\) wittrockiana_) and dragoncillo (_Antirithinum majus_ L.) (_[PERSON] et al._, 2019). However, for pitito flower (_Tropaeolum pentaphyllum_), cornflower (_Centurea cyanus_ L.), elderberry (_Sambucus nigra L._), chamomile (_Matricaria_ L.) and Vulneraria (_Anthyllis vulneraria_ L.), lower values were found, as reported by [PERSON] et al. (2019) and [PERSON] et al. (2020). Similar outcomes have been obtained in other studies, in which the carotenoid content varies according to the species of flower under study (_[PERSON] et al._, 2019). Carotenoids are found in all anatomical parts of the flower: sepals, pollen, anthers, stamens, and petals (_[PERSON] et al._, 2019). Consuming foods rich in carotenoids, including edible flowers, can alleviate diabetic retinopathy symptoms, improve glutathione peroxidation, and lower blood cholesterol levels, which ultimately contributes to efficient protection from nontransmissible chronic diseases (_[PERSON] et al._, 2019; _[PERSON] et al._, 2019).