Eunkyung Lee

Britanin suppresses LPS-induced nitric oxide, PGE2 and cytokine production via NF-κB and MAPK inactivation in RAW 264.7 cells.

Little is known about the biological properties of britanin, which is isolated from the flowers of Inula japonica (Inulae Flos). Based on our previous studies that Inulae Flos had anti-inflammation and anti-asthmatic activities, we tried to find the bioactive compounds from it. In this study, the anti-inflammatory effects of britanin on the inflammatory mediators as well as on nuclear factor (NF)-кB and mitogen-activated protein (MAP) kinase activation were evaluated in RAW 264.7 cells. Britanin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) along with the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In addition, britanin reduced the release of pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6. Furthermore, the phosphorylations of MAP kinases (p38 and JNK) in LPS-stimulated RAW 264.7 cells were suppressed by britanin. Moreover, britanin inhibited the NF-κB activation induced by LPS, which was associated with the abrogation of IκBα degradation and subsequent decreases in nuclear p65 levels. This study suggests that the anti-inflammatory activities of britanin might be attributed to the inhibition of iNOS and COX-2 and cytokine expression at least in part, through the attenuation of the phosphorylations of MAP kinases and NF-κB activation via IκBα degradation in macrophages. We conclude that britanin may have potential for the treatment of inflammatory diseases through the down-regulation of MAP kinases and NF-κB mediated activation of macrophages.

Silver nanoparticles-mediated G2/M cycle arrest of renal epithelial cells is associated with NRF2-GSH signaling

Silver nanoparticles (nAg) are known to evoke reactive oxygen species (ROS) generation and consequent cell damage. The transcription factor NF-E2-related factor 2 (NRF2) controls both the basal and inducible expression of multiple antioxidant genes. This study was aimed to investigate the role of NRF2 in nAg-induced renal epithelial cell damage. nAg treatment intensified DNA damage and G2/M cell cycle arrest by nAg in NRF2 knockdown HK-2 (NRF2i) compared with the control cells. As a signaling mechanism associated with nAg-mediated growth arrest, the levels of phospho-CDC25C and phospho-CDC2 were significantly increased in NRF2i. Target gene analysis revealed that nAg-mediated increase in γ-glutamate cysteine ligase expression is NRF2-dependent: nAg-treated NRF2i showed a reduction in glutathione (GSH) content and elevation in ROS level in comparison with the control cells. Additionally, pretreatment of N-acetylcystein in nAg-treated NRF2i alleviated ROS-mediated DNA damage and G2/M cell cycle arrest, while GSH depletion exacerbated DNA damage and cell cycle arrest in the control cells. Taken together, these results suggest that NRF2-mediated GSH increase plays a protective role in nAg-induced DNA damage and subsequent G2/M cell cycle arrest in human renal epithelial cells.

Alleviation of OVA-Induced Airway Inflammation by Flowers of Inula japonica in a Murine Model of Asthma

The flowers of Inula japonica (Inulae Flos) have long been used in traditional medicine for treating inflammatory diseases. The effects on OVA-induced asthmatic mice of an Inulae Flos extract (IFE) were evaluated in this study. The anti-asthmatic effects of IFE were determined by observing eosinophil recruitment, airway hyper-responsiveness (AHR), Th2 cytokine and IgE levels, and lung histopathology. The IFE treatment effectively reduced the percentage of eosinophils and Th2 cytokines in the bronchoalveolar lavage fluid (BALF) when compared to the levels in OVA-induced mice. IFE also suppressed AHR induced by aerosolized methacholine in OVA-induced mice. The results of the histopathological studies indicate that inflammatory cell infiltration and mucus hypersecretion were both inhibited by the IFE administration when compared to the effect on OVA-induced mice. The IFE treatment also suppressed the serum IgE levels and decreased Th2 cytokines in the supernatant of cultured splenocytes. These results suggest that IFE may have therapeutic potential against asthma.

Effects of methyl gallate on arachidonic acid metabolizing enzymes: Cyclooxygenase-2 and 5-lipoxygenase in mouse bone marrow-derived mast cells

Methyl gallate (MG) is a medicinal herbal product that is isolated fromPaeonia lactiflora that inhibits cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 (PGD2) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with an IC50 values of 17.0 μM. This compound also found inhibited the COX-2-dependent conversion of the exogenous arachidonic acid to PGD2 in a dose-dependent manner with an IC50 values of 19.0 μM, using a COX enzyme assay kit. However, at concentrations up to 80 μM, MG did not inhibit COX-2 protein expression in BMMC, indicating that MG inhibits COX-2 activity directly. Furthermore, MG consistently inhibited the production of leukotriene C4 (LTC4) in a dose dependent manner, with an IC50 value of 5.3 μM. These results demonstrate that MG has a dual cyclooxygenase-2/5-lipoxygenase inhibitory activity, which provide the basis for novel anti-inflammatory drugs.

Fermentation with Aquilariae Lignum enhances the anti-diabetic activity of green tea in type II diabetic db/db mouse.

The major components of tea may be significantly influenced according to the type of fermentation, and consequently the effects of different teas will differ. We examined whether green tea fermented with Aquilariae Lignum (fGT) shows a stronger anti-diabetic effect than unfermented green tea (GT) on mice with type 2 diabetes. To evaluate the anti-obesity effect of fGT, we assessed body weight, fecal excretion, serum leptin levels, exocrine pancreatic zymogen granule contents, and periovarian fat weight and adiponectin contents. Blood glucose levels, pancreatic weight, and numbers of pancreatic islet insulin- and glucagon-producing cells were determined to evaluate anti-hypoglycemic effects, while total cholesterol, triglyceride, and low- and high-density lipoprotein levels were determined to evaluate anti-hyperlipidemic effects. The antioxidant effect of fGT was detected by measuring malondialdehyde and glutathione contents and the activities of catalase and superoxide dismutase. fGT showed anti-obesity, anti-hypoglycemic, anti-hyperlipidemia, and antioxidant effects. Additionally, fGT exerted stronger anti-diabetic effects compared with GT. Collectively, these results suggested that fGT fermented with the appropriate amounts of Aquilariae Lignum (49:1) has a stronger effect compared with GT. Thus, fGT is a promising and potent new therapeutic agent for type 2 diabetes.

Flowers of Inula japonica Attenuate Inflammatory Responses

Background The flowers of Inula japonica (Inulae Flos) have long been used in traditional medicine for the treatment of inflammatory diseases. In the present study, we investigated the anti-inflammatory properties of Inulae Flos Extract (IFE). Methods The anti-inflammatory effects of IFE against nitric oxide (NO), PGE2, TNF-α, and IL-6 release, as well as NF-κB and MAP kinase activation were evaluated in RAW 264.7 cells. Results IFE inhibited the production of NO and the expression of inducible nitric oxide synthase (iNOS) in LPS-stimulated RAW264.7 cells. In addition, IFE reduced the release of pro-inflammatory cytokines, such as TNF-α and IL-6. Furthermore, IFE inhibited the NF-κB activation induced by LPS, which was associated with the abrogation of IκB-α degradation and subsequent decreases in nuclear p65 and p50 levels. Moreover, the phosphorylation of ERK, JNK, and p38 MAP kinases in LPS-stimulated RAW 264.7 cells was suppressed by IFE in a dose-dependent manner. Conclusion These results suggest that the anti-inflammation activities of IFE might be attributed to the inhibition of NO, iNOS and cytokine expression through the down-regulation of NF-κB activation via suppression of IκBα and MAP kinase phosphorylation in macrophages.

Naturally occurring biflavonoid, ochanflavone, inhibits cyclo-oxygenases-2 and 5-lipoxygenase in mouse bone marrow-derived mast cells

Ochnaflavone is a medicinal herbal product isolated from Lonicera japonica that inhibits cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 (PGD2) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with IC50 values of 0.6μM. Western blotting probed with specific anti-COX-2 antibodies showed that the decrease in quantity of the PGD2 product was accompanied by a decrease in the COX-2 protein level. In addition, this compound consistently inhibited the production of leukotriene C4 (LTC4) in a dose dependent manner, with an IC50 value of 6.56 μM. These results demonstrate that ochnaflavone has a dual cyclooxygenase-2/5-lipoxygenase inhibitory activity. Furthermore, this compound strongly inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 3.01 μM. Therefore, this compound might provide a basis for novel anti-inflammatory drugs.

6-Amino-2,4,5-trimethylpyridin-3-ols: A new general synthetic route and antiangiogenic activity

A new synthetic strategy for preparation of a wide range of 6-amino-2,4,5-trimethylpyridin-3-ols from pyridoxine·HCl via a six-step sequence has been developed. This approach features an introduction of various amino groups to C(6)-position of 3-benzyloxy-6-bromo-2,4,5-trimethylpyridine (13), a key intermediate, by a Buchwald-Hartwig amination reaction using palladium(0) transition metal, which certainly renders an expanded scope of amino substituents. Some analogs prepared using the methods described here showed high level of antiangiogenic and antitumor activities in chick chorioallantoic membrane (CAM) assay, demonstrating the potential of these new aminopyridinols as antiangiogenic agents.

miR-27 regulates mitochondrial networks by directly targeting the mitochondrial fission factor

Mitochondrial morphology is dynamically regulated by forming small, fragmented units or interconnected networks, and this is a pivotal process that is used to maintain mitochondrial homeostasis. Although dysregulation of mitochondrial dynamics is related to the pathogenesis of several human diseases, its molecular mechanism is not fully elucidated. In this study, we demonstrate the potential role of miR-27 in the regulation of mitochondrial dynamics. Mitochondrial fission factor (MFF) mRNA is a direct target of miR-27, whose ectopic expression decreases MFF expression through binding to its 3′-untranslated region. Expression of miR-27 results in the elongation of mitochondria as well as an increased mitochondrial membrane potential and mitochondrial ATP level. Our results suggest that miR-27 is a novel regulator affecting morphological mitochondrial changes by targeting MFF.

IVSE, isolated from Inula japonica,suppresses LPS-induced NO production via NF-κB and MAPK inactivation in RAW264.7 cells.

AIMS Our previous study showed that the extract of Inula japonica Thunb. (I. japonica) has anti-inflammatory and anti-asthmatic activities. In an attempt to find anti-inflammatory compounds from I. japonica, we recently isolated 1,6α-dihydroxy-4αH-1,10-secoeudesma-5(10),11(13)-dien-12,8β-olide (SE), 6α-isobutyryloxy-1-hydroxy-4αH-1,10-secoeudesma-5(10),11(13)-dien-12,8β-olide (IBSE), and 6α-isovaleryloxy-1-hydroxy-4αH-1,10-secoeudesma-5(10),11(13)-dien-12,8β-olide (IVSE) from the extract of I. japonica, and investigated their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. MAIN METHODS The inhibitory effect of IVSE, SE and IBSE on NO production in LPS-induced RAW264.7 cells was examined using Griess reagent, and the effects of IVSE on the expressions of inducible nitric oxide synthase (iNOS) and its upstream signal proteins including IκB kinase (IKK)/inhibitor kappa B (IκB)-α/nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) were investigated by Western blot. KEY FINDINGS Among the 3 compounds isolated, SE, IBSE, and IVSE inhibited NO production at 2.5 μM with 5.1%, 40.4%, and 52.8%, respectively. IVSE displayed the most potent inhibition of NO production. Mechanism analysis indicated that IVSE dramatically decreased the expression of iNOS, reduced the translocation of the NF-κB subunit p65 into the nucleus by interrupting the phosphorylation and degradation of IκB-α, and inhibited the activation of the upstream mediator IKK α/β. Furthermore, our results showed that IVSE inhibited the phosphorylation of MAPKs including extracellular regulated kinases (ERK1/2), c-Jun N-terminal kinases (JNK) and p38. SIGNIFICANCE IVSE exhibited anti-inflammatory activity by inhibiting NO production, in which inactivation of NF-κB and MAPKs might be involved. Our results suggest that IVSE might become an anti-inflammatory drug candidate.