Extract of Aster koraiensis Nakai Leaf Ameliorates Memory Dysfunction via Anti-inflammatory Action.

Aster koraiensis Nakai (AK) leaf reportedly ameliorates health problems, such as diabetes. However, the effects of AK on cognitive dysfunction or memory impairment remain unclear. This study investigated whether AK leaf extract could attenuate cognitive impairment. We found that AK extract reduced the production of nitric oxide (NO), tumour necrosis factor (TNF)-α, phosphorylated-tau (p-tau), and the expression of inflammatory proteins in lipopolysaccharide- or amyloid-ß-treated cells. AK extract exhibited inhibitory activity of control specific binding on N-methyl-D-aspartate (NMDA) receptors. Scopolamine-induced AD models were used chronically in rats and acutely in mice. Relative to negative controls (NC), hippocampal choline acetyltransferase (ChAT) and B-cell lymphoma 2 (Bcl2) activity was increased in rats chronically treated with scopolamine and fed an AK extract-containing diet. In the Y-maze test, spontaneous alterations were increased in the AK extract-fed groups compared to NC. Rats administered AK extract showed increased escape latency in the passive avoidance test. In the hippocampus of rats fed a high-AK extract diet (AKH), the expression of neuroactive ligand-receptor interaction-related genes, including Npy2r, Htr2c, and Rxfp1, was significantly altered. In the Morris water maze assay of mice acutely treated with scopolamine, the swimming times in the target quadrant of AK extract-treated groups increased significantly to the levels of the Donepezil and normal groups. We used Tg6799 Aß-overexpressing 5XFAD transgenic mice to investigate Aß accumulation in animals. In the AD model using 5XFAD, the administration of AK extract decreased amyloid-ß (Aß) accumulation and increased the number of NeuN antibody-reactive cells in the subiculum relative to the control group. In conclusion, AK extract ameliorated memory dysfunction by modulating ChAT activity and Bcl2-related anti-apoptotic pathways, affecting the expression of neuroactive ligand-receptor interaction-related genes and inhibiting Aß accumulation. Therefore, AK extract could be a functional material improving cognition and memory.

UPLC-MS/MS-Based Profiling of Eicosanoids in RAW264.7 Cells Treated with Lipopolysaccharide.

While both the pro- and anti-inflammatory effects of several eicosanoids have been widely studied, the degree of inflammation in cells that results from various eicosanoids has yet to be comprehensively studied. The objective of this study was to assess the effect of lipopolysaccharide (LPS) treatment on eicosanoid content in RAW264.7 cells. An Ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS)-based profiling method was used to analyze the eicosanoid contents of RAW264.7 cells treated with different LPS concentrations. The profiling data were subjected to statistical analyses, such as principal component analysis (PCA) and hierarchical clustering analysis. LPS treatment increased nitric oxide production and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, in a concentration-dependent manner. In total, 79 eicosanoids were identified in the cells. RAW264.7 cells treated with different LPS concentrations were well differentiated in the PCA score plot. A heatmap was used to identify the eicosanoids that were up- or down-regulated according to the degree of inflammation and LPS concentration. Thirty-nine eicosanoids were upregulated and seven were down-regulated by LPS treatment in a concentration-dependent manner. Our novel UPLC-MS/MS technique can profile eicosanoids, and can evaluate the correlations between inflammation and eicosanoid metabolism.

Anti-inflammatory cycloartane-type saponins of Astragalus membranaceus.

A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-ß-(2'-O-acetyl)-D-xylopyranosyl-6-O-ß-D-glucopyranosyl-(24S)-3ß,6α,24α,25-tetrahydroxy- 9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

Modulation of NF-κB and FOXOs by baicalein attenuates the radiation-induced inflammatory process in mouse kidney.

The bioactive flavonoid baicalein has been shown to have radioprotective activity, although the molecular mechanism is poorly understood in vivo. C57BL/6 mice were irradiated with X-rays (15 Gy) with and without baicalein treatment (5 mg/kg/day). Irradiation groups showed an increase of NF-κB-mediated inflammatory factors with oxidative damage and showed inactivation of FOXO and its target genes, catalase and SOD. However, baicalein suppressed radiation-induced inflammatory response by negatively regulating NF-κB and up-regulating FOXO activation and catalase and SOD activities. Furthermore, baicalein inhibited radiation-induced phosphorylation of MAPKs and Akt, which are the upstream kinases of NF-κB and FOXOs. Based on these findings, it is concluded that baicalein has a radioprotective effect against NF-κB-mediated inflammatory response through MAPKs and the Akt pathway, which is accompanied by the protective effects on FOXO and its target genes, catalase and SOD. Thus, these findings provide new insights into the molecular mechanism underlying the radioprotective role of baicalein in mice.

The anti-inflammatory action of fermented soybean products in kidney of high-fat-fed rats.

Soybean has many compounds with a variety of biological properties that potentially benefit human health; among them, isoflavones have inhibitory effects on lipid oxidation in adipose tissue. In this study, we examined two Korean traditional fermented soybean products--doenjang (DNJ) and cheonggukjang (CGJ)--for their ability to suppress redox-sensitive nuclear factor κB (NF-κB) activation in the kidney of rats fed a high-fat diet. Sprague-Dawley rats, 4 weeks old, were fed soybean, DNJ, or CGJ (1 g/kg/day) with a 20% fat diet for 6 weeks. Body weight and food intake were carefully monitored. NF-κB-related activities of genes for inflammatory proteins, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and vascular cell adhesion molecule-1 (VCAM-1), were determined. The soybean products exhibited antioxidative action by maintaining redox regulation, suppressing NF-κB activation, and modulating the expression of genes for NF-κB-induced inflammatory proteins such as COX-2, iNOS, and VCAM-1. Based on these results, we conclude that Korean traditional soybean fermented products, especially CGJ, suppress the generation of reactive species, NF-κB activity, and NF-κB-related inflammatory genes.

Molecular basis for age-related changes in ileum: involvement of Bax/caspase-dependent mitochondrial apoptotic signaling.

Previous studies indicate that in the elderly, a morphological change in the small intestine is accompanied by apoptosis. However, currently little information is available on the molecular events leading up to the apoptotic process in aged ileum. Our current study assessed mitochondrial apoptotic signaling along with key factors known to be involved in mitochondrial permeabilization in rat ileum. Experimentations were carried out utilizing Sprague-Dawley rats at 6 and 24 months of age. The histological analysis showed a significant loss in thickness of the intestinal mucosa during aging, which was accompanied by higher reactive species. Molecular analysis revealed the mitochondrial translocation of Bax showed a significant increase with aging. However, the expression of cyclophilin D, adenine nucleotide translocator, and the voltage-dependent anion channel that regulates the mitochondria permeability transition pore decreased or remained unchanged. Furthermore, the expression of caspase 3 was enhanced in aged ileum with increased DNA fragmentation, while nuclear translocation of apoptosis-inducing factor and endonuclease G were decreased with aging. In conclusion, our findings indicate that the mitochondrial translocation of Bax by increased oxidative stress may result in cell death through caspase-dependent apoptosis in aged ileum, thereby leading to a decrease in intestinal mucosal thickness during aging.

A high-fat diet impairs neurogenesis: involvement of lipid peroxidation and brain-derived neurotrophic factor.

Obesity is a growing global health problem that contributes to diabetes, hypertension, cardiovascular diseases, dementia, and cancer. The increased consumption of saturated fats in a high-fat diet (HFD) contributes to obesity, neurodegenerative diseases, long-term memory loss, and cognitive impairment. We tested whether HFD influences adult hippocampal neurogenesis. Male C57BL/6 mice were divided into two groups and maintained on either a normal diet (ND) or HFD. Seven weeks of HFD significantly decreased the numbers of newly generated cells in the dentate gyrus of the hippocampus without neuronal loss. HFD also increased the level of malondialdehyde (MDA) and decreased the level of brain-derived neurotrophic factor (BDNF) in the hippocampus. The toxic effects of MDA were evaluated on neural progenitor cells (NPCs). MDA reduced the growth of NPCs, but BDNF treatment restored NPCs proliferation. The present data indicate that a HFD impairs hippocampal neurogenesis and NPCs proliferation through increased lipid peroxidation and decreased BDNF.

A newly synthesized, potent tyrosinase inhibitor: 5-(6-hydroxy-2-naphthyl)-1,2,3-benzenetriol.

In searching for new agents with a depigmenting effect, we synthesized a derivative of resveratrol, 5-(6-hydroxy-2-naphthyl)-1,2,3-benzenetriol (5HNB) with a potent tyrosinase inhibitory activity. 5HNB inhibited mushroom tyrosinase with an IC(50) value of 2.95 microM, which is more potent than the well-known anti-tyrosinase activity of kojic acid (IC(50)=38.24). The results of the enzymatic inhibition kinetics by Lineweaver-Burk analysis indicated 5HNB inhibits tyrosinase non-competitively when L-tyrosine was used as the substrate. Based on the strong inhibitory action of 5HNB, it is expected that 5HNB can suppress melanin production in which tyrosinase plays the essential role. Our expectation was confirmed by the experimentations with B16 melanoma cells in which 5HNB inhibited melanin production. We propose that 5HNB might have skin-whitening effects as well as therapeutic potential for treating skin pigmentation disorders.

5-Hydroxytrytophan inhibits tert-butylhydroperoxide (t-BHP)-induced oxidative damage via the suppression of reactive species (RS) and nuclear factor-kappaB (NF-kappaB) activation on human fibroblast.

5-Hydroxytryptophan (5HTP), an analogue of tryptophan, is a precursor of serotonin that also has effective antioxidative and anti-apoptotic properties (1) . However, the cellular mechanisms underlying these properties of 5HTP have not been explored. In this study, we tested the hypothesis that 5HTP exerts its antioxidative action against oxidative stress and inflammation by suppressing the activation of the key pro-inflammatory transcriptional pathways, p38 mitogen-activated protein kinase (p38MAPK) and nuclear factor-kappaB (NF-kappaB). The study was carried out using human fibroblast cells that were challenged by tert-butylhydroperoxide (t-BHP)-induced oxidative damage. Results show that 5HTP significantly reduced t-BHP-induced oxidative damage in human fibroblast cells, as determined by cell cytotoxicity, intracellular reactive species (RS) and peroxynitrite (ONOO(-)) generation, and inducible nitric oxide synthase expression. Moreover, 5HTP protected human fibroblast cells against t-BHP-induced oxidative DNA damage, as determined by 4,6-diamidino-2-phenlylindole (DAPI) staining. Pretreatment of human fibroblast cells with 5HTP also dose-dependently inhibited glutathione (GSH) depletion, indicating that it protects cells against t-BHP-induced oxidative damage. Western blot analysis revealed that 5HTP also markedly increased Bcl-2 expression and suppressed both p38MAPK and NF-kappaB activation in the t-BHP-treated human fibroblast cells. When these results are taken together, they strongly indicate that 5HTP has beneficial and protective effects against t-BHP-induced cell death in vitro, as demonstrated by its antioxidative and anti-inflammatory actions. Data further showed that the protective mechanisms underlying the actions of 5HTP against oxidative stress-induced damage are associated with RS/ONOO(-) scavenging and the inhibition of lipid peroxidation and GSH depletion.

The anti-apoptotic action of 5-hydroxyindole: protection of mitochondrial integrity.

5-Hydroxyindole (5HI), a metabolite of tryptophan, is involved in learning and memory, central neuron system regulation, and anti-oxidant activity. However, its protective action in mitochondrial function is not clear. Here, we tested whether 5HI protects against tert-butylhydroperoxide (t-BHP)-induced oxidative damage and mitochondrial dysfunction in human fibroblast cells. 5HI significantly suppressed t-BHP-induced cytotoxicity as determined by intracellular reactive species generation, lipid peroxidation, glutathione depletion, and peroxynitrite (ONOO(-)) generation. In addition, 5HI reduced t-BHP-induced DNA condensation. Pretreatment with 5HI significantly restored mitochondrial membrane potential (Deltapsim), suggesting that it protected cells against t-BHP-induced apoptosis. Western blot analysis also revealed that 5HI markedly inhibited cytochrome c release and caspase-3 activation, but not caspase-9 activation. Our data suggest that 5HI protects cells by attenuating oxidative stress and consequently protects against mitochondrial dysfunction.