Ethnopharmacological validation of Calotropis gigantea L. flower extract against rheumatoid arthritis: Anti-arthritic and immunomodulatory effects in a CFA-induced rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Calotropis gigantea (L.) is traditionally used in South Asian folk medicine for inflammatory disorders, joint pain, and rheumatic conditions. However, its anti-arthritic efficacy has not been systematically validated in an experimental arthritis model.

AIM OF THE STUDY: This study investigated the anti-arthritic, antioxidant, and immunomodulatory effects of an ethanolic extract of Calotropis gigantea flowers (EECG) in Complete Freund Adjuvant (CFA) induced rheumatoid arthritis in rats.

MATERIALS AND

METHODS

EECG was prepared by Soxhlet extraction and characterized using GC-MS. Anti-inflammatory potential was initially assessed by an in vitro protein denaturation assay. Arthritis was induced in Swiss albino rats using CFA, followed by oral administration of EECG (100, 200, and 400 mg/kg) for 28 days. Clinical parameters, hematological indices, inflammatory biomarkers (C-reactive protein, rheumatoid factor), oxidative stress markers, and mRNA expression of IL-6, TNF-α, NF-κB, and COX-2 were evaluated. Histopathological examination of ankle joints was performed.

RESULTS

GC-MS analysis identified 19 phytoconstituents, with 5-hydroxymethylfurfural, n-hexadecanoic acid, and 9,12,15-octadecatrienoic acid as major components. EECG showed dose-dependent inhibition of protein denaturation (81.24% at 1000 μg/mL). In vivo, EECG significantly reduced paw edema, arthritic score, organ hypertrophy, CRP, and RF levels while improving hematological and antioxidant parameters. Pro-inflammatory gene expression was markedly downregulated. Histology confirmed preservation of synovial architecture and reduced pannus formation, particularly at 400 mg/kg, comparable to diclofenac.

CONCLUSIONS

These findings scientifically validate the traditional use of C. gigantea for inflammatory joint disorders and support its potential as a phytotherapeutic candidate for rheumatoid arthritis.