## 3 Results and Discussion
### Phenolic Compound Identification by HPLC/ESI/MS
\begin{table}
\begin{tabular}{c c c c c} \hline
**Flower** & **Peak** & **Rt (min)** & **[M-H]-(m/z)** & **Compound** & **Family** \\ \hline \multirow{9}{*}{_Cylindrupantia rose_} & 1 & 3.85 & 340.8 & Caffe acid 4-O-glucose & Hydroxycinamic acids \\  & 2 & 33.25 & 710.7 & Quercetin 3-O-(6′′-malonyl-glucose) 7-O-glucose & Flavonols \\  & 3 & 34.59 & 608.8 & Quercetin 3-O-glycos-glucuron & Flavonols \\  & 4 & 35.62 & 462.8 & Quercetin 3-O-glucose & Flavonols \\  & 5 & 37.08 & 504.8 & Peonidin 3-O-(6′′-acetyl-glucose) & Anthocyanins \\  & 6 & 39.53 & 488.8 & Quercetin 3-O-acetyl- rhamnoside & Flavonols \\  & 7 & 47.33 & 314.9 & Protocatechu acid 4-O-glucose & Hydroxybenzoic acids \\  & 8 & 48.70 & 1086.7 & Unknown & \\  & 9 & 49.49 & 894.8 & Prodelphinidn trimer GC-GC-C & Proanthocyanidin trimmers \\  & 10 & 51.90 & 358.8 & Rosmarinic acid & Hydroxycinnamic acids \\  & 11 & 52.46 & 299 & 4-Hydroygennic acid 4-O-glucose & Hydroxybenzoic acids \\  & 12 & 54.47 & 301 & Quercetin & Flavonols \\  & 13 & 55.73 & 283 & Geraldone & Methoxyflavones \\  & 14 & 56.59 & 315 & Protocatechu acid 4-O-glucose & Hydroxybenzoic acids \\  & 15 & 59.20 & 358.9 & Rosmarinic acid & Hydroxycinnamic acids \\ \hline \multirow{9}{*}{_Opuntia oligacanthu_} & 1 & 3.47 & 249 & Ferulydglycine & Hydroxycinnamic acids \\  & 2 & 25.55 & 238.9 & Isopropyl & \\  & 3 & 27.57 & 354.9 & Ferulic acid 4-O-glucose & Methoxycinnamic acids \\  & 4 & 31.69 & 370.8 & Stinnestein & Methoxyflavones \\  & 5 & 34.04 & 768.8 & Unknown & \\  & 6 & 35.24 & 462.8 & Quercetin 3-O-glucose & Flavonols \\  & 7 & 36.67 & 622.9 & Isorhametin 3-O-glucose \(\mathcal{T}\)-O-hamnoside & Methoxyflavonols \\  & 8 & 37.63 & 476.9 & Isorhametin 3-O-glucose & Methoxyflavonols \\  & 9 & 42.01 & 828.6 & Sesammient 2-O-trigulos & Lignans \\  & 10 & 53.90 & 312.8 & Crismaritin & Methoxyflavones \\ \hline \multirow{9}{*}{_Opuntia mutudae_} & 1 & 23.39 & 354.8 & Ferulic acid 4-O-glucose & Methoxycinnamic acids \\  & 2 & 24.11 & 354.8 & Ferulic acid 4-O-glucose (isomero) & Methoxycinnamic acids \\  & 3 & 25.77 & 238.9 & Isopropyl & \\  & 4 & 27.78 & 354.9 & Conidendrin & Lignans \\  & 5 & 31.50 & 370.9 & Stinnestein & Methoxyflavones \\  & 6 & 33.73 & 768.8 & Unknown & \\  & 7 & 33.76 & 768.8 & Unknown & \\  & 8 & 35.13 & 462.9 & Quercetin 3-O-glucose \(\mathcal{T}\)-O-hamnoside & Flavonols \\  & 9 & 36.73 & 622.9 & Isorhametin 3-O-glucose \(\mathcal{T}\)-O-hamnoside & Methoxyflavonols \\  & 10 & 37.67 & 476.9 & Isorhametin 3-O-glucose & Methoxyflavonols \\  & 11 & 42.37 & 798.7 & Ellagic acid derivative & Hydroxybenzoic acids \\  & 12 & 44.71 & 652.8 & Malvidin 3,5-O-diglucoside & Anthocyanins \\ \hline \multirow{9}{*}{_Echinocreus_} & 1 & 22.91 & 288.9 & (+)-Catechin & Catechins \\  & 2 & 22.07 & 289 & (-)-Epicatechin & Catechins \\  & 3 & 31.88 & 771.1 & Quercetin 3-O-glucose/hyl-glucose & Flavonols \\ \cline{1-1}  & 4 & 32.87 & 609.1 & Quercetin 3-O-xylosyl-glucuron & Flavonols \\ \cline{1-1}  & 5 & 35.10 & 593.1 & Apigenin 6,8-di-C-glucose & Flavones \\ \cline{1-1}  & 6 & 30.03 & 859 & Unknown & \\ \cline{1-1}  & 7 & 48.14 & 329.2 & 3.7-Dimethyljuercetin & Methoxyflavonols \\ \hline \end{tabular}
\end{table} 
Table 4: Identification of polyphenonic compounds by HPLC/ESI/MS of cactus flowers from Hidalgo, Mexico. \(m/z\) 462.8 in XU and peak 8, with Rt 35.13 min and m/z 462.9 in XC). In PI flowers, the main compound detected was identified as flavone apigenin 6, 8-di-C-glucose (peak 5, with Rt 35.10 min and \(m/z\) 592.1), followed by flavonoids such as quercetin 3-O-xylosil-glucoronide (peak 4, with Rt 32.87 and \(m/z\) 609.1), and methoxyflavonols such as 3,7-dimethylquercetin (peak 7, with Rt 48.14 and \(m/z\) 329.2). Quercetin and its derivatives were the main secondary metabolites found in the flowers analyzed in this study; it is a natural flavonoid widely distributed in plants, fruits and vegetables in a glycosylated form.