HPLC -DAD analysis, anti-inflammatory and anti-arthritic potentials of Coronopus didymus (L.) Sm. extracts: effects on pro- and anti-inflammatory cytokines, COX-2, I-κβ, NF-κβ and oxidative stress biomarkers.

Coronopus didymus (L.) Sm. (CD) has been traditionally used to treat pain, rheumatism, and inflammation. This study was planned to appraise the anti-oxidant, anti-inflammatory and anti-arthritic potentials of CD (whole plant) aqueous ethanolic (CDAEE) and aqueous extracts (CDAE) and chemical characterization by high-performance liquid chromatography-diode array detector. In vivo anti-inflammatory (Carrageenan induced paw edema, and Xylene induced ear edema assays) and anti-arthritic potentials were evaluated in Wistar rats. Both extracts showed significant (p < 0.0001) in vitro free radical scavenging and in vitro anti-arthritic potentials by inhibition of protein denaturation and stabilization of the HRBC membrane and anti-oedematogenic potential, whereas more activity was expressed by CDAEE. In complete Freund's adjuvant-induced arthritic model, the CDAEE at 200, 400, and 800 mg kg-1 and methotrexate (1 mg kg-1) profoundly (p < 0.05) reduced the arthritic score and paw edema, restored body and immune organ weight, and altered blood parameters and oxidative stress biomarkers. The qRT-PCR analysis revealed that CDAEE at 400 mg kg-1 significantly (p < 0.0001) downregulated TNF-α (2.22 ± 0.16 fold), IL-6 (2.29 ± 0.05 fold), IL-1β (2.10 ± 0.01 fold), COX-2 (2.45 ± 0.02 fold), and NF-ĸβ (2.72 ± 0.06 fold) and considerably upregulated IL-10 (58.84 ± 0.67%), IL-4 (76.16 ± 2.79%) and I-kβ (75.45 ± 0.17%) in arthritic rats in contrast to disease control and methotrexate as evidenced from the joint histology. These findings suggested the antioxidant, anti-inflammatory and anti-arthritic activities of C. didymus, which might be due to the presence of quercetin, ferulic acid, dihydromyricetin, apigenin, vitexin, and kaempferol in CDAEE.