# An Updated Review: _Opuntia focus indica_ (OFI) Chemistry and Its Diverse Applications
## 2 Nutritional and Phytochemicals
### Phytochemicals  
#### 2.2.1 Polyphenolic Compounds  
Polyphenolic compounds belong to a class of organic compounds commonly found in the plant kingdom. This class is divided into four major groups, which are stilbenes, flavonoids, lignans, and suberin-acids. These compounds control cell destruction initiated by oxidative stress and free radicals, enhance blood flow, minimize the threat of heart disease, decrease neurodegenerative ailments, and improve cognitive function. The common assembly of OFI polyphenols is represented in Figure 4.  
As the name suggests, polyphenic compounds are characterized by the presence of various phenolic groups, which may be linked with low- or high-molecular-weight groups of chemicals to form their structures [44]. These compounds are by-products of plant metabolism [45]. The growing interest in polyphenic compounds is due to their antioxidant ability [46] and health benefits [47]. Polyphonic compounds are present in all components of the cactus plant, such as a variety of polyphenic acids and flavonoids (Table 6). The flower contains gallic acid as the main compound of dry matter (4900 mg/100 g), along with 6-isorhamtein-3-O-robinobioside (C\({}_{28}\)H\({}_{32}\)O\({}_{16}\)) at a concentration of 4269.00 mg/100 g [48; 49; 50]. The remaining polyphenic compounds have appeared on a small scale (Table 4). The pulp of OFI fruit is a rich source of phenolic content, with 218.80 mg/100 g present in the pulp [51]. Additionally, the isorhamtein glycoside is present in a significant amount, 50.60 mg/100 g, in comparison to other flavonoids [52; 53; 54; 55]. The fruit seeds are also high in polyphenic compounds, including tannins and feruloyl derivatives [56] (Table 4). Notably, the fruit crust contains a remarkable (45.7 g/100 g) phenolic content; among the various phenolic compounds present, many have been found to have bioactive properties, particularly the derivatives of flavonoid quercetin  
Figure 4: General forms of OFI polyphenols: (**A**) general form of flavonoids, (**B**) general form of hydroxycinnamates, (**C**) general form of flavonoids, (**D**) general form of flavones.  
and kaempfer (both are beneficial for heart diseases, Alzheimer diseases, anti-cancer effects, arthritis, and diabetes and improve memory function); the contents are 0.22 mg/100 g and 4.32 mg/100 g, respectively [7; 57; 53]. The highest significant source of flavonoids and polyphenolic compounds is the cactus flower. In particular, some types of cacti that have clades yield a diverse range of phenolic compounds. The Phaeacantha cactus contains a rich quantity of rare compounds of flavonoids such as narcissin (137.10 mg/0.1 kg) and nicotiiflorin (146.50 mg/0.1 kg) (see Table 6). In addition, it contains a significant amount of isoquercetin (39.70 mg/100 g) and ferulic acid (34.8 mg/100 g) [55; 58; 59]. The variations in the polyphenolic contents of cacti can be explained by the nature of the soil, climate, cladode age, and environment. It is valuable to take a diet with wealthy polyphenolic compounds to obtain a full array of advantages.