NCB-02 (standardized Curcumin preparation) protects dinitrochlorobenzene-induced colitis through down-regulation of NFκ-B and iNOS

Abstract

To evaluate the efficacy and mechanism of action of NCB 02, a standardized Curcumin preparation, against 2, 4 dinitrochlorobenzene (DNCB) induced ulcerative colitis in rats. Ulcerative colitis was induced in male rats by sensitizing with topical application of DNCB in acetone for 14 d and intra-colonol challenge with DNCB on day 15. A separate group of animals with vehicle treatment in similar fashion served as control group. Colitis rats were divided into different groups and treated with NCB-02 at doses of 25, 50 and 100 mg/kg b.wt p.o. for 10 d. Sulfasalazine at a dose of 100 mg/kg b.wt for 10 d served as a reference group. On day 10 after respective assigned treatment, all the animals were euthanized and the length of the colon, weight of entire colon and distal 8 cm of the colon were recorded. The distal part of the colon was immediately observed under a stereomicroscope and the degree of damage was scored. Further distal 8 cm of the colon was subject to the determination of colonic myeloperoxidase (MPO), lipid peroxidation (LPO) and alkaline phosphatase (ALP) activities. A small piece of the sample from distal colon of each animal was fixed in 10% neutral buffered formalin and embedded in paraffin wax and sectioned for immunohistochemical examination of NFkappa-B and iNOS expression. NCB-02 showed a dose dependent protection against DNCB-induced alteration in colon length and weight. NCB-02 treatment also showed a dose dependent protection against the elevated levels of MPO, LPO and ALP, induced by DNCB. NCB-02 demonstrated a significant effect at a dose of 100 mg/kg b.wt., which was almost equipotent to 100 mg/kg b.wt. of sulfasalazine. Treatment with sulfasalazine and curcumin at a dose of 100 mg/kg b.wt. inhibited the DNCB-induced overexpression of NFkappa-B and iNOS in the colon. Curcumin treatment ameliorates colonic damage in DNCB induced colitic rats, an effect associated with an improvement in intestinal oxidative stress and downregulation of colonic NFkappa-B and iNOS expression.