Phytochemical-Mediated Modulation of Oxidative Stress and Inflammatory Pathways: A Preclinical Evaluation of Turmeric (Curcuma longa) Rhizome Methanolic Extract in Albino Rats

Turmeric is an important plant with many health benefits classified under the family of ginger. This study was conducted to evaluate the phytochemical composition, antioxidant capacity, and anti-inflammatory effects of turmeric extract using qualitative, quantitative, in vitro, and in vivo approaches. Methods such as DPPH, FRAP, and lipoxygenase inhibition assays were employed. Result of the qualitative phytochemical screening revealed the presence of several secondary metabolites, including alkaloids, flavonoids, phenols, tannins, terpenoids, steroids, glycosides, and volatile oils, with flavonoids, phenols, and tannins being particularly abundant. Quantitative analysis confirmed high concentrations of phenols (112.5 mg GAE/g), flavonoids (84.6 mg QE/g), tannins (42.8 mg TAE/g), and terpenoids (27.5 mg/g), indicating strong antioxidant potential. In vitro antioxidant assays demonstrated concentration-dependent activity. The DPPH assay showed up to 81.5% radical scavenging at 400 µg/mL (IC₅₀ = 122.4 µg/mL), while the FRAP assay confirmed considerable ferric-reducing capacity, though slightly lower than that of ascorbic acid. In vivo studies revealed that toxin exposure significantly decreased antioxidant enzymes (SOD, CAT, and GSH) and increased lipid peroxidation (MDA). Treatment with turmeric extract (200 and 400 mg/kg) markedly improved antioxidant enzyme levels and reduced MDA in a dose-dependent manner. The 400 mg/kg dose nearly restored normal values and showed effects comparable to Vitamin E. Furthermore, the extract significantly reduced pro-inflammatory cytokines (TNF-α and IL-6), with the higher dose demonstrating anti-inflammatory activity similar to diclofenac. Findings from this study demonstrate that turmeric extract is a potent source of bioactive compounds with robust antioxidant and anti-inflammatory activities. Its ability to enhance endogenous antioxidant defenses and suppress pro-inflammatory cytokines may support its therapeutic potential in conditions involving oxidative stress and inflammation.