AIM:To study effect of diterpenoid C extracted from radix curcumae on Helicobacter pylori(H.pylori)-infected inflammation,intestinal metaplasia,and nuclear factor kappa B(NF-κB)signaling pathway in vitro.METHODS:We used I-type H.pylori to infect human gastric epithelial gastric epithelium cell line(GES-1)cell lines,and then H.pylori-infected GES-1 cells were treated with radix curcumae(RC)-derived diterpenoid C of different concentrations(5,10,20μg/mL)and amoxicillin.The expression of p65,IκB kinase(IKK)αand IKKγproteins was detected with Western blotting,and the expression of interleukin(IL)-8,IL-6 and IL-4 was determined with enzyme-linked immunosorbent assay method.Data were analyzed using SPSS software ver18.0.For comparisons between groups of more than two unpaired values,one-way analysis of variance(ANOVA)was used.If an ANOVA F value was significant,post hoc comparisons were performed between groups.If results were not normally distributed,the Mann-Whitney U test was used to compare two groups of unpaired values,whereas for comparisons between groups of more than two unpaired values,the Kruskal-Wallis H test was used.Statistical significance was established at P<0.05.RESULTS:The MTT assay results revealed the inhibited rate of GES-1,and indicated that the IC5 of RCderived diterpenoid C and amoxicillin all were 5μg/mL for gastric GES-1 cells.The expression of IL-8 was significantly increased,especially at 12 h time point;and the expression of IL-4 was decreased in H.pyloriinfected GES-1 cells.After H.pylori-infected GES-1 cells were treated with RC-derived diterpenoid C of different concentrations and amoxicillin,the expression of IL-8was decreased at 12,24,48,72 h points(P<0.01),especially in high-concentration diterpenoid C(20μg/mL)group;and the expression of IL-4 was increased,especially in moderate and high-concentration diterpenoid C(10 and 20μg/mL)groups.RC-derived diterpenoid C had the inhibitory effects on H.pylori-induced p65 translocation from cytoplasm into cell nucleus,H.pylori-stimulant IkBαdegradation,the phosphorylation of p65 and IkBα,and the expression of IKKαand IKKβproteins.CONCLUSION:RC-derived diterpenoid C can block NF-κB signal pathway,effectively reducing the secretion of H.pylori-induced proinflammatory cytokine and increasing the secretion of anti-inflammatory cytokine. AIM: To study effect of diterpenoid C extracted from radix curcumae on Helicobacter pylori (H. pylori) -infected inflammation, intestinal metaplasia, and nuclear factor kappa B (NF-κB) signaling pathway in vitro. METHODS: We used I- type H .pylori to infect human gastric epithelial gastric epithelium cell line (GES-1) cell lines, and then H. pylori-infected GES-1 cells were treated with radix curcumae (RC) -derived diterpenoid C of different concentrations (5, IκB kinase (IKK) α and IKKγproteins was detected with Western blotting, and the expression of interleukin (IL) -8, IL-6 and IL-4 was determined with enzyme-linked immunosorbent assay method. Data were analyzed using SPSS software ver18.0. For comparisons between groups of more than two unpaired values, one-way analysis of variance (ANOVA) was used. It an ANOVA F value was significant, post hoc comparisons were performed between groups.If results were not normally distributed, the Mann-Whitney U test was used to compare two groups of unpaired values, whereas for comparisons between groups of more than two unpaired values, the Kruskal-Wallis H test was used. Statistical significance was established at P <0.05.RESULTS: The MTT assay results revealed the inhibited rate of GES- 1 and indicated that the IC5 of RC derived diterpenoid C and amoxicillin all were 5 μg / mL for gastric GES-1 cells. The expression of IL-8 was significantly increased, especially at 12 h time point; and the expression of IL-4 was decreased in H. pylori infected GES-1 cells. After H. pylori-infected GES-1 cells were treated with RC-derived diterpenoid C of different concentrations and amoxicillin, the expression of IL-8 was decreased at 12, 24, 48, 72 h points (P <0.01), especially in high-concentration diterpenoid C (20 μg / mL) group; and the expression of IL-4 was increased, especially in moderate and high-concentration diterpenoid C -deved diterpenoid C had the inhibitory effects on H. pylori-induced p65 translocation from cytoplasm into cell nucleus, H. pylori-stimulant IkBα degradation, the phosphorylation of p65 and IkBα, and the expression of IKKαand IKKβproteins.CONCLUSION: RC-derived diterpenoid C can block NF-κB signaling pathway, reducing reducing the secretion of H. pylori- induced proinflammatory cytokine and increasing the secretion of anti-inflammatory cytokine.