Abstract
INTRODUCTION: Chronic inflammation is implicated in a multitude of diseases, including arthritis, neurodegeneration, autoimmune myositis, type 2 diabetes, rheumatic disorders, spondylitis, and cancer. Therefore, strategies to explore potent anti-inflammatory regimens are pivotal from a human-health perspective. Medicinal plants represent a vast unexplored treasure trove of therapeutically active constituents with diverse pharmacological activities, including anti-inflammatory properties. Herein, we evaluated Cousinia thomsonii, an edible medicinal herb, for its anti-inflammatory/immunomodulatory properties. METHODS: Soxhlet extraction was used to obtain different solvent extracts (hexane, ethyl acetate, ethanol, methanol, and aqueous extract) in increasing order of polarity. In vitro anti-inflammatory assays were performed to investigate the effects of extracts on protein denaturation, proteinase activity, nitric oxide surge, and erythrocyte-membrane stabilization. The most effective extracts, ie, ethyl acetate (CTEA) and ethanol (CTE) extracts (150-200 g) were selected for further in vivo analysis using albino Wistar rats. Wistar rats received varying concentrations of CTEA and CTE (25, 50, and 100 mg/kg) for 3 weeks, followed by a single subplantar injection of lipopolysaccharide. Dexamethasone served as positive control. Blood was obtained from the retro-orbital plexus and serum separated for estimation of proinflammatory cytokines (IL6, IL1β, IFNγ and TNFα). Western blotting was performed to study expression patterns of crucial proteins implicated in the NFκB pathway, ie, NFκB p65, NFκB1 p50, and NFκB2 p52. Histopathological examination was done and gas chromatography-mass spectrometry (GC-MS) carried out to reveal the identity of compounds responsible for ameliorating effects of C. thomsonii. RESULTS: Among five tested extracts, CTEA and CTE showed marked inhibition of protein denaturation, proteinase activity, nitric oxide surge and erythrocyte-membrane hemolysis at 600 μg/mL (P<0.001). Both these extracts showed no toxic effects up to a dose of 2,500 mg/kg. Extracts exhibited concentration-dependent reductions in expression of IL6, IL1β, IFNγ, TNFα, NFκB-p65, NFκB1, and NFκB2 (P<0.05). Healing effects of extracts were evident from histopathological investigation. GC-MS analysis revealed the presence of important anti-inflammatory compounds, notably stigmast-5-en-3-ol, oleate, dotriacontane, ascorbic acid, n-hexadecanoic acid, and α-tocopherol, in C. thomsonii. CONCLUSION: C. thomsonii possesses significant anti-inflammatory/immunomodulatory potential by virtue of modifying levels of proinflammatory cytokines/markers and NFκB proteins.