Anti-inflammatory Effect of Microwave-Assisted <i>Opuntia humifusa</i> Extract (MA–OHE) against DSS-Induced Colitis

Ulcerative colitis (UC), including chronic colitis, is characterized by severe inflammation and oxidative stress in the colon. This study investigated the therapeutic potential of microwave-assisted <i>Opuntia humifusa</i> extract (MA-OHE), prepared using water (WE) and water-methanol (WME) solvents, in a chronic colitis model in mice induced by dextran sodium sulfate (DSS). Chemical profiling using UV-vis, FTIR, and HPLC analyses revealed that WME contains significantly higher concentrations of phenolic and flavonoid compounds than WE. These bioactive compounds enhance the antioxidant capacity of WME, as demonstrated by the superior radical scavenging activity in DPPH and ABTS assays and more pronounced suppression of nitric oxide (NO) synthesis in RAW 264.7 cells activated with LPS. In the DSS-induced chronic colitis model, treatment with WME notably enhanced colitis indicators, such as by restoring body weight, lowering the disease activity index (DAI) score, and maintaining colon length. Additionally, MA-OHE (WME) treatment decreased proinflammatory cytokine levels, such as TNF-α, IL-6, and IL-1β, in a dose-dependent manner, demonstrating strong anti-inflammatory effects. Histological examination additionally validated the recovery of colonic crypts and goblet cells and the reduction in inflammatory infiltration in groups treated with MA-OHE. These findings highlight the enhanced therapeutic potential of WME compared with that of WE, which is attributed to its richer composition of bioactive compounds. MA-OHE, particularly WME, demonstrated strong antioxidant, anti-inflammatory, and tissue-protective effects, indicating its potential as a natural treatment for chronic colitis management. Proinflammatory cytokine level modulation underscores its effectiveness in mitigating inflammation and supporting colonic tissue recovery.