Inhibitory Effect of Black Radish (Raphanus sativus L. var. niger) Extracts on Lipopolysaccharide-Induced Inflammatory Response in the Mouse Monocyte/Macrophage-Like Cell Line RAW 264.7.

Black radish (Raphanus sativus L. var. niger), which is cultivated worldwide, is used in traditional medicine as it aids liver function, gastric secretion, gallbladder function, and gallstone mitigation. In this study, we examined the anti-inflammatory effects of black radish extract (BRE) on the lipopolysaccharide (LPS)- and interleukin (IL)-6-mediated inflammatory responses in the RAW 264.7 cell lines. Our findings show that BRE significantly ameliorated LPS-induced nitric oxide (NO) release and production of pro-inflammatory cytokines, such as IL-1ß, IL-6, tumor necrosis factor (TNF)-α, and prostaglandin E2. The levels of cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) in LPS-stimulated RAW 264.7 cells were found to be suppressed by BRE. Further, BRE significantly suppressed the LPS-induced expression of mRNAs encoding COX-2, iNOS, IL-1ß, IL-6, and TNF-α in a concentration-dependent manner. BRE treatment significantly inhibited Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) phosphorylation in IL-6- and LPS-treated RAW 264.7 cells. In addition, BRE decreased the levels of phosphorylated extracellular signal-regulated protein kinases and c-Jun N-terminal kinase under the same conditions. Moreover, BRE induced high nuclear factor erythroid 2-related factor 2 (NRF2) levels and its target gene heme oxygenase 1 (HO-1) in the absence of LPS. These data demonstrate that BRE may be beneficial for treating inflammation through selective immunomodulatory effects, which may be mediated by inhibition of the STAT3/JAK2 and activation of the NRF2/HO-1 signal transduction pathways.

Fermented black radish (Raphanus sativus L. var. niger) attenuates methionine and choline deficient diet-induced nonalcoholic fatty liver disease in mice.

As one of the wide-ranging form of chronic liver disease, there are only limited therapeutic options for nonalcoholic fatty liver disease (NAFLD). We evaluated whether fermented black radish (Raphanus sativus L. var. niger; FBR) ameliorates lipid accumulation, inflammation, and hepatic fibrosis, which are characteristics of the pathogenesis of NAFLD. Fermented black radish treatment reduced lipid accumulation in 3T3-L1 adipocytes, which appeared to be associated with the downregulation of adipogenic transcription factors, including sterol regulatory element-binding protein 1c, CCAAT/enhancer-binding protein α, peroxisome proliferator-activated receptor γ, and lipid accumulation-related genes including adipocyte protein-2 and fatty acid synthase. Administration of FBR to C57BL/6J mice challenged with methionine and choline deficient (MCD) diet significantly attenuated the increased serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and triglyceride. In addition, treatment with FBR interestingly repressed the hepatic inflammation induced with MCD diet, by lowering the expression of inducible nitric oxide synthase and suppressing the inactivation of macrophages and Kupffer cells in the liver. Fermented black radish was also shown to mitigate liver fibrosis through the inhibition of alpha-smooth muscle actin, transforming growth factor beta-1, and collagen type I alpha 1 chain. Our results indicate that FBR ameliorates NAFLD and its related metabolic disease by regulating multiple pathways, suggesting that FBR may be an effective dietary supplement for ameliorating NAFLD.

Anti-inflammatory effect of salidroside on phorbol-12-myristate-13-acetate plus A23187-mediated inflammation in HMC-1 cells.

Salidroside [2-(4-hydroxyphenyl)ethyl ß-D-gluco-pyranoside (SAS)] has been identified as the most potent ingredient of the plant Rhodiola rosea L. Previous studies have demonstrated that it possesses a number of pharmacological properties, including anti-aging, anti-fatigue, antioxidant, anticancer and anti-inflammatory properties. In this study, to ascertain the molecular mechanisms responsible for the anti-inflammatory activity of SAS, we used phorbol-12-myristate-13-acetate (PMA) plus A23187 to induce inflammation in human mast cell line-1 (HMC-1). The HMC-1 cells were treated with SAS prior to being stimulated with PMA plus A23187. Pro-inflammatory cytokine production was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Western blot analysis was used to examine the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB). SAS inhibited the mRNA expression and production of interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF). In cells stimulated with PMA plus A23187, SAS suppressed the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and c-jun N-terminal kinase 1/2 (JNK1/2), but not that of p38 MAPK. SAS suppressed the expression of NF-κB in the nucleus. On the whole, our results suggest that SAS exerts an anti-inflammatory effect by inhibiting the production of pro-inflammatory cytokines through the blocking of the NF-κB and MAPK signaling pathways.

Quercetin prevents adipogenesis by regulation of transcriptional factors and lipases in OP9 cells.

With the industrialization of society, the increase in the prevalence of obesity and metabolic disorders has become an important health concern in a number of countries. Quercetin (3,30,40,5,7-pentahydroxyflavone) is well known as a bioactive flavonoid in a variety of biological resources. The aim of the present study was to explore the machanisms responsible for the anti-adipogenic activity of quercetin and its effects on the lipolysis in OP9 mouse stromal cells which rapidly differentiate into adipocytes. The differentiation of OP9 cells into adipocytes was evaluated by the measurement of lipid accumulation by Oil Red O (ORO) staining; lipid accumulation was significantly impaired by treatment with quercetin. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis were used to measure the expression levels of CCAAT/enhancer binding protein α (C/EBPα), proliferator-activated receptor γ (PPARγ), sterol regulatory element-binding protein-1 (SREBP-1) and fatty acid synthase (FAS). The mRNA expression levels of lipases, such as adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL) and lipoprotein lipase (LPL) were also measured by RT-PCR. Quercetin significantly decreased the expression of transcription factors, including C/EBPα, PPARγ and SREBP-1c both at the protein and mRNA level. The results from the present study demonstrate that quercetin prevents adipogenesis by upregulating ATGL and HSL expression and downregulating FAS, LPL and adipocyte fatty acid-binding protein (aP2) expression, as well as the expression of transcription factors. Our data suggest that quercetin has therapeutic potential by regulating the expression of transcriptional factors and enzymes associated with adipogenesis.

Protective effect of ixerisoside A against UVB-induced pro-inflammatory cytokine production in human keratinocytes.

Human skin is the first line of defense for the protection of the internal organs of the body from different stimuli. Ultraviolet B (UVB), one of the harmful radiations for skin, is widely known to induce abnormally increased cytokine release from keratinocytes leading to inflammatory skin disorders. IL-6 and IL-8 induce an acute-phase response and stimulate leukocyte infiltration in the skin. Previous studies have shown that chronic exposure to UVB radiation increases cyclooxygenase-2 (COX­2) expression through various cell signaling pathways, resulting in skin cancer. Recent studies have shown that the activation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK is strongly correlated with acute inflammation and development of skin cancer caused by an increased expression of COX-2. Ixerisoside A (IXA) is an active constituent of Ixeris dentata of the Compositae (Asteraceae) family. The effect of IXA on skin inflammation has yet to be elucidated. To determine the anti-inflammatory effects of IXA, we examined its effect on UVB-induced pro-inflammatory cytokine production in human keratinocytes (HaCaT cells) by observing these cells in the presence or absence of IXA. In this study, pro-inflammatory cytokine production was determined by enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (rt-pcr), and western blot analysis to evaluate the activation of mitogen-activated protein kinases (MAPKs). IXA inhibited UVB-induced production of the pro-inflammatory cytokines IL-6 and IL-8 in a dose-dependent manner. Moreover, IXA inhibited the expression of COX-2, ERK, JNK, and p38 MAPKs, indicating that the secretion of the pro-inflammatory cytokines IL-6 and IL-8, and COX-2 expression was inhibited by blocking MAPK phosphorylation. These results indicated that IXA potentially protects against UVB-induced skin inflammation.

Synergistic effect of rhein in combination with ampicillin or oxacillin against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for a number of infections in humans that are difficult to treat, and as a result, is a substantial contributor to morbidity and mortality. In the present study, in search of natural products capable of inhibiting this multidrug-resistant bacterium, we investigated the antimicrobial activity of rhein isolated from Rheum palmatum L. (Polygonaceae) against 16 different strains of the bacterium. New antimicrobial activity was found using the paper disc diffusion method [minimal inhibitory concentrations (MICs)], MTT test and checkerboard dilution test. Against the 16 strains, the disc diffusion test was in the range of 20-29 mm and the MICs of rhein were in the range of 7.8-31.25 µg/ml. From these results we performed the checkerboard test to determine the synergism of rhein in combination with ampicillin (AM) or oxacillin (OX) against all strains. The combined activity of rhein and the two antimicrobial agents (AM and OX) against all strains resulted in a fractional inhibitory concentration index ranging from 0.28-1 and from 0.18-1, respectively. The effect of rhein with AM and OX was found to be synergistic or partially synergistic. We found that rhein reduced the MICs of AM and OX. Rhein in combination with AM or OX could lead to the development of new combinations of antibiotics against MRSA infection.