Euphol and Experimental Colitis Figure 5. Euphol treatment inhibits NOS2 and VEGF expression in colonic tissue. After a 7-day euphol treatment, colon samples were processed for immunohistochemistry analysis. Preventive treatment with euphol (30 mg/kg, p.o.) significantly reduced NOS2 (A) and VEGF (B) immunostaining in the colon tissue after DSS-induced colitis in mice. Graphical representation of the immunostaining for NOS2 (C) and VEGF (D) expression evaluated in colon tissue. The mean intensity of NOS2 and VEGF staining were determined from image analysis and are represented as optical density. Scale bar corresponds to 100 mm and applies throughout. Each column represents the mean 6 S.E.M. of 8 to 10 mice per group and is representative of three independent experiments. #P,0.05 vs. control healthy group (non colitic); *P,0.05 vs. DSS-treated group. doi:10.1371/journal.pone.0027122.g005 inflammation of intestinal mucosa [30,31]. Despite intense interest, the pathogenesis of IBD still remains poorly understood; the imbalance between pro-inflammatory cytokines, such as TNF- a, IFN-c, IL-1b, IL-6 and IL-12, and anti-inflammatory cytokines, such as IL-4, IL-10 and IL-11, is thought to play a pivotal role in modulating gut inflammation [32]. It has been reported that these inflammatory responses begin with a sudden infiltration of neutrophils and macrophages [33] with the activated macrophages producing a potent combination of broadly active inflammatory cytokines, including TNF- a, IL-1 and IL-6 [34]. Conventional therapy for IBD relies on the use of aminosalicylates, corticoste- roids, immunosuppressive drugs and antibiotics [35]. Nowadays a new class of drugs has been used for the treatment of IBD, among them biologic agents such as anti-TNF therapy are noteworthy [36,37]. However, these therapies for IBDs are usually associated with several side effects or clinical limitations for use. Therefore, there is a need for better therapeutic agents that effectively induce remission and/or alter the natural course of the disease with minimum or no side effects of treatment. The use of medicinal plants or their active components is becoming an increasingly attractive approach for the treatment of various inflammatory disorders, such as rheumatoid arthritis [38,39], multiple sclerosis {Ma, #622; Martin, #623; De Paula, 2008 #624} and ulcerative colitis [28]. Euphol, the alcohol derivate tetracyclic triterpene is the main constituent found in the sap of Euphorbia tirucalli, which is used as a folk therapy against syphilis, asthma, rheumatism, cancer and sarcoma [17]. In addition, a recent study have demonstrate that a biopolymeric fraction (BET) obtained from E. tirucalli showed dose-dependent anti-arthritic activity and demonstrated in vivo suppression of CD4+ and CD8+ T cells associated with the inhibition of intracellular IL-2 and IFN-c, and inhibited vascular permeability PLoS ONE | www.plosone.org 7 November 2011 | Volume 6 | Issue 11 | e27122