Curcuminoids-enriched extract and its cyclodextrin inclusion complexes ameliorates arthritis in complete Freund's adjuvant-induced arthritic mice via modulation of inflammatory biomarkers and suppression of oxidative stress markers

Curcuma longa extract and its marker curcuminoids have potential use in inflammatory conditions. However, curcuminoids solubility and bioavailability are major hindrances to their bioactivity. The current study investigated green extraction-based curcuminoids-enriched extract (CRE) prepared from C. longa and its cyclodextrin inclusion complexes, i.e., binary inclusion complexes (BC) and ternary inclusion complexes (TC), in complete Freund's adjuvant (CFA)-induced mice for their comparative anti-arthritic efficacy. CRE, BC, and TC (2.5 and 5 mg/kg) with the standard drug diclofenac sodium (13.5 mg/kg) were orally administered to mice for 4 weeks. Variations in body weight, hematological and biochemical parameters, along with gene expression analysis of arthritis biomarkers, were studied in animals. The histopathological analysis and radiographic examination of joints were also performed. CRE, BC and TC treatment significantly restored the arthritic index, histopathology and body weight changes. The concentration of C-reactive protein, rheumatoid factor and other liver function parameters were significantly recovered by curcuminoids formulations. The pro-inflammatory cytokines (NF-kappa B, COX-2, IL-6, IL-1 beta, and TNF-alpha) gene expression was considerably (p < 0.001) downregulated, while on the other side, the anti-inflammatory genes IL-4 and IL-10 were upregulated by the use of CRE and its complexes. The concentration of antioxidant enzymes was considerably (P < 0.001) recovered by CRE, BC and TC with marked decrease in lipid peroxidation, erosion of bone, inflammation of joints and pannus formation in comparison to arthritic control animals. Therefore, it is concluded that green CRE and its cyclodextrin formulations with enhanced solubility could be considered as an applicable therapeutic choice to treat chronic polyarthritis.