Rosmarinus officinalis L. extract ameliorates intestinal inflammation through MAPKs/NF-κB signaling in a murine model of acute experimental colitis.

We investigated the anti-inflammatory and anti-colitis effects of Rosmarinus officinalis L. extract (RE) by using both in vitro LPS-activated mouse RAW 264.7 macrophages and in vivo dextran sulfate sodium (DSS)-induced experimental murine colitis and suggested the underlying possible mechanisms. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis was performed to identify the major components present in the RE. The clinical signs, biochemistry, immunoblot, ELISA and histology in colon tissues were assessed in order to elucidate the beneficial effect of RE. RE suppressed the LPS-induced pro-inflammatory cytokine production and the expressions of inflammatory proteins in macrophages. Administration of RE (50 and 100 mg kg(-1)) also significantly reduced the severity of DSS-induced murine colitis, as assessed by the clinical symptoms, colon length and histology. RE administration prevented the DSS-induced activation of p38, ERK and JNK MAPKs, attenuated IκBα phosphorylation and subsequent nuclear translocation and DNA binding of NF-κB (p65). RE also suppressed the COX-2 and iNOS expressions, decreased the levels of TNF-α and IL-6 cytokines and the myeloperoxidase activity in the colon tissue. Histological observation revealed that RE administration alleviated mucosal damage and inflammatory cell infiltration induced by DSS in the colon tissue. Hence, RE could be used as a new preventive and therapeutic food ingredient or as a dietary supplement for inflammatory bowel disease.