Novel mannich-based derivative of 2-mercaptobenzimidazole (AK7): a new candidate for the treatment of inflammatory arthritis owing to its NF-κB1 inhibitory potential

This study investigated the anti-arthritic potential of novel mannich-based derivatives of 2-mercaptobenzimidazole (AK7 and AK9) in rats. The compounds were characterized by NMR and FTIR spectroscopies and their acute anti-inflammatory effects were measured by carrageenan (CRG)-induced paw edema model. The most potent doses of AK7 and AK9 were subsequently evaluated in the complete Freund's adjuvant (CFA)-induced inflammatory arthritis model. AK7 and AK9 inhibited CRG-induced inflammation in a dose-dependent fashion and a similar reduction in CFA-induced paw inflammation was observed. Moreover, X-ray and histopathological analyses of AK7-treated animals displayed normal joint structure whereas AK9, despite of its anti-inflammatory effects, failed to protect against cartilage destruction. Interestingly, biochemical analysis revealed a better safety profile for AK7 than for AK9 and methotrexate. Both compounds suppressed mRNA levels of pro-inflammatory mediators (IRAK1, NF-κB1, TNF-α, IL1B) while only AK7 reduced the transcript levels of interstitial collagenase (MMP1). Molecular docking analysis of AK7 and AK9 with TNF-α and MMP1 also supported the experimental data. These findings clearly highlight the beneficial effects of AK7 in the prevention and/or treatment of inflammatory arthritis.