Protective effects of watercress (Nasturtium officinale) leaf methanolic extract against dextran sodium sulfate induced colon inflammation in rats.

Numerous factors can lead to inflammation and enlargement of the colon, posing a serious health risk. This study investigated the protective effects of watercress (Nasturtium officinale) leaf methanolic extract against dextran sodium sulfate (DSS)-induced colonic inflammation in rats. Phytochemical analysis showed high levels of polyphenols, flavonoids, and condensed tannins in the methanolic extract, which exhibited the strongest in vitro anti-diabetic (α-amylase and α-glucosidase enzymes; Inhib. % 72.61 and 62.36%, respectively), anti-Alzheimer (AChE; Inhib. % 65.86 ± 0.15%), and anti-arthritic activity (protein denaturation and the proteinase enzyme activity; Inhib. % 58.09 ± 0.14 and 55.39 ± 0.14%, respectively) and was therefore selected for the in vivo study. Oxidative stress and inflammatory responses in colon tissue were evaluated using biochemical tests, histopathological examination, and assessment of mRNA levels of inflammatory markers (NF-κB, IL-6, IL-1β) and antioxidant enzymes (SOD1, CAT, GPx1). Watercress extract treatment successfully reinstated antioxidant enzyme activity and decreased inflammatory indicators in both pre-treated and post-treated cohorts. Histopathological examinations demonstrated a significant enhancement in the architecture of colon tissue and a decrease in inflammatory lesions. Molecular assays confirmed normalization of mRNA expression of antioxidant enzymes and inflammatory markers disrupted by DSS administration (p ≤ 0.05). These findings indicate that the methanolic extract of watercress leaves exerts protective effects against DSS-induced colonic inflammation at biochemical, histological, and molecular levels, supporting its potential as a natural anti-inflammatory agent.