Anti-inflammatory effects of proanthocyanidin-rich red rice extract via suppression of MAPK, AP-1 and NF-κB pathways in Raw 264.7 macrophages

BACKGROUND/OBJECTIVES: Several pharmacological properties of red rice extract have been reported including anti-oxidant, anti-tumor, and reduced cancer cell invasion. This study was conducted to evaluate the anti-inflammatory effects of red rice extract on the production of inflammatory mediators in lipopolysaccharide (LPS)-induced Raw 264.7 macrophages. MATERIALS/METHODS: Pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-6 were determined by ELISA and cyclooxygenase-2 and inducible nitric oxide synthase expression was evaluated using western blot analysis. In addition, the signaling pathway controlling the inflammatory cascade such as nuclear factor kappa B (NF-κB), activator proteins-1 (AP-1), and mitogen-activated protein kinase (MAPK) was determined. RESULTS: Our results showed that red rice polar extract fraction (RR-P), but not non-polar extract fraction, inhibited interleukin-6, tumor necrosis factor-α, and nitric oxide production in LPS-induced Raw 264.7 cells. RR-P also reduced the expression of inflammatory enzymes, inducible nitric oxide synthase, and cyclooxygenase-2. In addition, activation of AP-1 and NF-κB transcription factor in the nucleus was abrogated by RR-P. RR-P inhibited the phosphorylation of extracellular signaling-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 MAPK signaling responsible for the expression of inflammatory mediators in LPS-stimulated Raw 264.7 cells. Based on chemical analysis, high amounts of proanthocyanidin and catechins were detected in the RR-P fraction. However, only proanthocyanidin reduced NF-κB and AP-1 activation in LPS-activated Raw 264.7 cells. CONCLUSION: These observations suggest that the anti-inflammatory properties of RR-P may stem from the inhibition of pro-inflammatory mediators via suppression of the AP-1, NF-κB, and MAPKs pathways.

Anti-inflammatory effects of proanthocyanidin-rich red rice extract via suppression of MAPK, AP-1 and NF-κB pathways in Raw 264.7 macrophages

BACKGROUND/OBJECTIVES: Several pharmacological properties of red rice extract have been reported including anti-oxidant, anti-tumor, and reduced cancer cell invasion. This study was conducted to evaluate the anti-inflammatory effects of red rice extract on the production of inflammatory mediators in lipopolysaccharide (LPS)-induced Raw 264.7 macrophages. MATERIALS/METHODS: Pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-6 were determined by ELISA and cyclooxygenase-2 and inducible nitric oxide synthase expression was evaluated using western blot analysis. In addition, the signaling pathway controlling the inflammatory cascade such as nuclear factor kappa B (NF-κB), activator proteins-1 (AP-1), and mitogen-activated protein kinase (MAPK) was determined. RESULTS: Our results showed that red rice polar extract fraction (RR-P), but not non-polar extract fraction, inhibited interleukin-6, tumor necrosis factor-α, and nitric oxide production in LPS-induced Raw 264.7 cells. RR-P also reduced the expression of inflammatory enzymes, inducible nitric oxide synthase, and cyclooxygenase-2. In addition, activation of AP-1 and NF-κB transcription factor in the nucleus was abrogated by RR-P. RR-P inhibited the phosphorylation of extracellular signaling-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 MAPK signaling responsible for the expression of inflammatory mediators in LPS-stimulated Raw 264.7 cells. Based on chemical analysis, high amounts of proanthocyanidin and catechins were detected in the RR-P fraction. However, only proanthocyanidin reduced NF-κB and AP-1 activation in LPS-activated Raw 264.7 cells. CONCLUSION: These observations suggest that the anti-inflammatory properties of RR-P may stem from the inhibition of pro-inflammatory mediators via suppression of the AP-1, NF-κB, and MAPKs pathways.

Effect of Curcuminoids on MDR Phenotype in Human Embryonic Kidney Cell Lines

Background: Resistance to chemotherapy chemicals is a major obstacle to sucessful treatment of cancer. Out of the mechanism of drug resistance is characterized by the overexpression of drug transporters on plasma membrane such as P-glycoprotein (Pgp), multidrug resistance associated protein (MRP), especially MRP1. Curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) were reportedly used to reverse multidrug resistance phenotype and increase chemotherapeutic sensitivity in cancer cells.Aim: To investigate the effect of three curcuminoids on cell cytotoxicity and MDR phenotype in HEK293pcDNA3.1MRP1 cell line (drug resistance cell line) and HEK293pcDNA3.1 cell line (parental drug sensitive cell line).Methods: Curcuminoids were examined for the effect on MDR phenotypes of the cells by cytotoxicity assay with MTT method. Treatments of cell lines with non-toxic dose (10 M) of curcuminoids in combination with varying doses of etoposide VP16 (0-200 M) for 72 hr were analysed.Results: Curcumin, demethoxycurcumin, and bisdemethoxycurcumin exhibited cytotoxic activity on HEK293pcDNA3.1 MRP1 cell line with IC50 of 62.5, 68.7, and 56.3 M, respectively.\  HEK293pc DNA3.1 showed IC50 of 53.1, 56.2, and 50 M, respectively.\  At non-toxic dose of bisdemethoxycurcumin exhibited the highest effect on MDR phenotype, followed by curcumin and demethoxycurcumin, respectively.Conclusion: Bisdemethoxycurcumin was an excellent MDR phenotype reversing which increased drug sensitivity in drug resistance cell line (HEK293pcDNA3.1MRP1 cell line). This finding shows the possibility of using curcuminoids as an MDR modulator in cancer patients however further experiments needs to be studied to achieve this goal.