Efficacy of green tea, its polyphenols and nanoformulation in experimental colitis and the role of non-canonical and canonical nuclear factor kappa beta (NF-kB) pathway: a preclinical in-vivo and in-silico exploratory study

Abstract

NF-kB plays a major role in the aetiopathogenesis of inflammatory-colitis. In this study, we evaluated the efficacy of green tea and its polyphenols and their nanoformulation in Tri-Nitro Benzene Sulfonic acid (TNBS) induced colitis in in-vivo system (Rat) and the involvement of non-canonical and canonical NF-kB pathway in green tea mediated protection (in-silico platform). We used the Wister rat model of TNBS-induced colitis. Rats were grouped into eleven groups (six animals each) and administered vehicle (ethanol), TNBS, Epicatechin (EC), Epigallocatechin (EGC), Epicatechin-gallate (ECG), Epigallocatechin-gallate (EGCG), sulfasalazine, green tea, EGCG + sulfasalazine, nano-EGCG and nano-EGCG + sulfasalazine for 14 days after induction of colitis. Colonic tissue was evaluated for the level of malondialdehyde, myeloperoxidase activity, catalase, reduced glutathione, glutathione peroxidase, IL-6, TNF-α, IL-1β, NF-κB and morphological and histopathological evidence of damage. In the in-silico part, molecular docking and dynamic simulation study of EGCG was done against different targets in NF-kB for detailed evaluation of the role of non-canonical and canonical NF-KB pathway. In our study, EGCG reduced colonic inflammation, markers of oxidative stress, TNF-α, NF-κB, IL-1β and IL-6. Nano-EGCG + sulfasalazine was more efficacious when compared to EGCG + sulfasalazine. In molecular docking and molecular dynamic simulation studies, EGCG showed a good binding profile to the inhibitor binding sites of IKK-beta, IKK-alpha and NIK. Thus, it can be concluded that EGCG showed protective action in experimental colitis acting through both non-canonical and canonical NF-kB pathway. Nano-EGCG + sulfasalazine combination showed better protection than nano-EGCG alone. Communicated by Ramaswamy H. Sarma.

Keywords: Epigallocatechin-gallate; NF-κB; TNBS; colitis; green tea; sulfasalazine.