Berberine ameliorates TNBS-induced colitis by inhibiting lipid peroxidation, enterobacterial growth and NF-κB activation.

Berberine, which is a major constituent of the rhizome of Coptidis japonica (CJ), inhibits IL-8 production in colonic epithelial cells and improves 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. In our preliminary studies, berberine inhibited lipid peroxidation in liposomes prepared from l-α-phosphatidylcholine as well as TLR-4-linked NF-κB activation in HEK cells. Therefore, to clarify its anticolitic mechanism, we examined the inhibitory effects of berberine in TNBS-induced colitic C3H/HeN and C3H/HeJ mice. Its oral administration inhibited macroscopic score, body weight gain, colon shortening, myeloperoxidase activity, and lipid peroxidation in the colons of TNBS-treated C3H/HeN and C3H/HeJ mice. Berberine inhibited colonic expression of iNOS, COX-2, IL-1β, IL-6, and TNF-α, but increased IL-10 expression in the colons of TNBS-treated C3H/HeN and C3H/HeJ mice. Berberine also inhibited NF-κB activation in TNBS-treated C3H/HeN and C3H/HeJ mice, and inhibited TLR-4 expression in C3H/HeN, but not C3H/HeJ, mice. Treating C3H/HeN and C3H/HeJ mice with berberine significantly reduced the number of Enterobacteriaceae induced by TNBS, but restored the number of Bifidobacteria reduced by TNBS. Furthermore, berberine potently inhibited LPS-induced inflammation in peritoneal macrophages mainly via NF-κB and weakly via MAPKs. Based on these findings, berberine may improve colitis by inhibiting lipid peroxidation, enterobacterial growth and NF-κB activation.