*3.2. Anti-Inflammatory Activity In Vivo*

Most of the in vivo works exploring the anti-inflammatory activity of *Opuntia* species were conducted using rats as animal models, following the carrageenan-induced inflammation method, which is frequently used to evaluate the anti-edematous effect of natural products (Table 2) [79].

A study by Ahmed et al. [77] reported the in vivo anti-inflammatory potential of different parts of *O. dillenii* with a high efficiency verified for the flowers, from which three isolated compounds, namely, kaempferol 3-*O*-α-arabinoside, isorhamnetin-3-*O*-β-Dglucopyranoside, and isorhamnetin-3-*O*-β-D-rutinoside, were characterized as the active principles contributing significantly to reducing paw edema in albino rats. Ammar et al. [65] also reported the anti-inflammatory potential for *Opuntia* sp. flowers; the authors found that the methanolic extracts of *O. ficus-indica* flowers exhibited an anti-inflammatory potential by reducing the paw edema size in Wistar rats, with the same efficiency as the non-steroidal anti-inflammatory drug indomethacin. This effect was confirmed by a significant decrease in the number of inflammatory cells, including leukocytes and lymphocytes, a decrease in malondialdehyde (MDA) levels, which is correlated with the decrease in the lipid peroxidation process occurring at inflammatory sites, and a restoration of some antioxidant enzymes' activities, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), which contribute to neutralize free radicals' overproduction. According to the phytochemical analysis, the authors suggested the implication of phenolic compounds, particularly quercetin, isorhamnetin, and kaempferol, which could scavenge free radicals and decrease inflammation. Moreover, Antunes-Ricardo et al. [83] found that *O. ficus-indica* cladodes' extract and its isolated isorhamnetin derivatives (isorhamnetin-3-*O*-glucosylrhamnosyl-rhamnoside and isorhamnetin-3-*O*-glucosyl-rhamnoside) decreased the amount of neutrophils' infiltration into the inflammatory site (carrageenan-induced air-pouch inflammation in rats) with a decrease in NO production more efficient than that obtained with the standard drug used, indomethacin. The authors also found that cladodes' extract and isolated compounds were able to inhibit COX-2 activity and cytokines' production, particularly TNF-α and IL-6, with a better efficiency for the crude sample, probably due to a synergistic effect of its different phytochemicals.
