## 4 Discussion  
The content of total phenols in the extracts (endocarp, mesocarp, pericarp, and whole fruit) of xoconostle Ulapa are higher than those reported by [PERSON] et al. [27], where the white Lent and Red Lent xoconostle were studied, which presented 29.61 mg EAG/100 g and 44.61 mg EAG/100 g, respectively, and those reported by [PERSON] et al. [28]. The differences between the species of these fruits can be influenced by environmental conditions (temperature, relative humidity, and light), as well as pre- and post-harvest handling, where the nutrition of the crop, the harvest index, among other factors can be included [27]. On the other hand, compared with [PERSON] et al. [26], it was found that the endocarp extract of xoconostle Ulapa (_Opuntia oligacantlu_ CF Forst) has a higher content of flavonoids (151.80 mg QE/100 g) than the endocarp extract of xoconostle (_Opuntia matudae_ Scheinvar cv. Rosa), where a content of 5 mg QE/100 g was reported; however, the flavonoid content is higher in the pericarp of xoconostle (_Opuntia matudae_ Scheinvar cv. Rosa) than in the pericarp of xoconostle Ulapa. Currently, no studies on tannins have been reported in xoconostle, but research has been carried out on other plants; for example, [PERSON] et al. [29] carried out a study on antioxidant activity and polyphenol content in sour Guava (_Psidium araa_) where it reports a tannin content of 5.02 mg CATE/g. [PERSON] et al. [30] found a content of condensed tannins in _Passiflora molissima_ curuba equivalent to 492.4 mg of CATE/100 g of dry pulp. On the other hand, [PERSON] et al. [31], in an investigation on the antioxidant capacity and content of tannins in pomeranate (_Punica grantum_), obtained 0.0061 mg equivalent of tannic acid per gram. In a study by [PERSON] et al. [32] applying tangarana (_Triplaris americana_ L.) endemic species of Latin America, a myrmecophilic tree, 0.1185 g of tannic acid/g were reported. As can be compared, the tannins in xoconostle Ulapa turn out to be lower and higher compared to those reported in other plant species; however, its content is also important and significant to provide beneficial health effects. Since these are considered bioactive compounds to which antioxidant, anti-inflammatory, antidiarrheal, and wound-healing properties have been attributed due to their free radical inhibition activity, so they can stop some of the anti-inflammatory processes in addition to having the ability to inhibit specific enzymes [31]. [PERSON] et al. [11] explain that the variability in the presence or absence of many bioactive compounds in leaves, fruits, roots, seeds, and other natural by-products could be mainly due to different abiotic factors such as the genotype of both the species and of the crops, as well as the conditions of growth of the fruits, the degree of maturity in the harvest, the climate, composition of the soil, humidity, temperature, and season mainly. A study by [PERSON] et al. [3] determined the inhibitory effect of different species on urease, which turned out to present high inhibition. Among these studied plants are _Camelia sinensis_, a plant native to China, which is currently cultivated throughout the world, whose leaves are used for the preparation of infusions of black tea and green tea; this species presented 95.4%; on the other hand _Citrus aurantifolia_, also called lime or lemon tree, had a higher inhibition value with 97.6% and another species to highlight its high gastroprotective power is _Nasturtium officinal_, commonly called watercress, with 99.13% inhibition of activity of urease. [PERSON] et al. [3] attribute inhibitory activity to flavonoids due to the presence of hydroxyl groups in the compounds, which can easily chelate with nickel (Ni) in the active site of urease; in the same way, [33] explain that dihydroxyl residues (-OH) in the C ring of flavonoids can interact with residues near the nickel atoms in the active site of urease in a similar way to thiourea.