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Abstract: Aims: This study was conducted to suggest the role of WNT/β-catenin pathway in the anti-adipogenic effect of platycodin D, a natural compound found in Platycodon grandiflorum. Main methods: Gene knockdown experiments using small interfering RNA (siRNA) transfection were conducted to elucidate crucial role of β-catenin in the anti-adipogenic effects of platycodin D. Real-Time PCR and Western blot were used to analyze the expression levels of mRNAs and proteins in the WNT/β-catenin pathway. Key findings: During the adipocyte differentiation of 3 T3-L1 cells, members of the WNT/β-catenin pathway were normally down-regulated, whereas platycodin D significantly reinstated the WNT/β-catenin pathway. The mRNA and protein expressions of disheveled (DVL) 2, which stabilize β-catenin, were increased by platycodin D treatment, but the protein level of AXIN, which induces the degradation of β-catenin, was decreased in platycodin D-treated cells. The nuclear level of β-catenin was normally down-regulated during adipogenesis, but platycodin D treatment led to the accumulation of β-catenin in the nucleus which resulted in the up-regulation of its target genes, cyclin D (CCND) 1 and peroxisome proliferator-activated receptor gamma (PPAR)γ. The anti-adipogenic effects of platycodin D were significantly attenuated in β-catenin siRNA-transfected cells compared with those of control siRNA-transfected cells. β-catenin siRNA transfection significantly recovered the levels of PPARγ, CCAAT/enhancer binding protein (C/EBP)α and fatty acid binding protein (FABP)4 as well as intracellular lipid droplet formation, all of which were reduced by platycodin D treatment. Significance: WNT/β-catenin pathway can be used as a therapeutic target of natural compounds for the regulation of adipogenesis. [Copyright &y& Elsevier]

Abstract: An increased level of melanin is characteristic of a large number of skin diseases, including acquired hyperpigmentation conditions such as melasma, postinflammatory melanoderma, and solar lentigo. Thus, there is an increasing need for the development of depigmenting agents. In order to evaluate the depigmenting capacity of diosgenin and elucidate its mechanism of action, several experiments were performed in B16 melanoma cells. Melanin content and Western blots for proteins that are involved in melanogenesis were assessed in this study. The melanin content was significantly inhibited by diosgenin. To clarify the mechanism of the depigmenting property of diosgenin, we examined the involvement of diosgenin in the phosphatidylinositol-3-kinase (PI3K) pathway. In this study, diosgenin inhibited the reduction of Akt and GSK 3β phosphorylation induced by LY294002, a PI3K inhibitor. In accordance with this result, production levels of MITF (microphthalmia-associated transcription factor) and tyrosinase were increased by diosgenin. These data suggest that diosgenin inhibits melanogenesis through the activation of the PI3K pathway. This suggestion was further confirmed by the fact that the increased production level of melanin by LY294002 was reduced by diosgenin in B16 melanoma cells. Our study shows that diosgenin inhibits melanogenesis by activating the PI3K pathway, and also suggests that diosgenin may be an effective inhibitor of hyperpigmentation. [Copyright &y& Elsevier]

Abstract: Aims: Previous studies have shown that isorhamnetin has anti-adipogenic effects in mouse 3T3-L1 cells. This study was conducted to elucidate the inhibitory mechanisms of isorhamnetin during adipogenic differentiation of human adipose tissue-derived stem cells (hAMSCs). Main methods: The effect of isorhamnetin on adipogenic differentiation of hAMSCs was quantified by Oil Red O staining and a triglyceride assay. In addition, real-time PCR and Western blot were used to determine the expression of adipogenesis-related genes. Key findings: Isorhamnetin inhibited the adipocyte differentiation of hAMSCs. Additionally, when the effects of Wnt antagonists that promote adipogenesis were evaluated, isorhamnetin was found to down-regulate the mRNA levels of sFRP1 and Dkk1, but had no effect on the mRNA levels of sFRP2, sFRP3, sFRP4 and Dkk3. Isorhamnetin also inhibited the expression of Wnt receptor and co-receptor genes. Furthermore, isorhamnetin increased the protein levels of β-catenin, an effector molecule of Wnt signaling, but had no effect on the mRNA levels of β-catenin. The phosphorylation level of GSK 3β was also increased by isorhamnetin. These results were confirmed by the fact that the expression of c-myc, cyclin D1 and PPARδ, which are target genes of β-catenin, was upregulated by isorhamnetin. Moreover, isorhamnetin reduced the mRNA expression levels of C/EBPα and PPARγ, which are known to be inhibited by c-myc or by cyclin D1 and PPARδ, respectively. Significance: Our results indicate that isorhamnetin inhibits the adipogenic differentiation of hAMSCs and that its mechanisms are mediated by the stabilization of β-catenin. [Copyright &y& Elsevier]

Abstract: Nodakenin is a coumarin compound initially isolated from the roots of Angelica gigas. In the present study, we investigated the effects of nodakenin on learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Nodakenin (10 mg/kg, p.o.) administration significantly reversed scopolamine-induced cognitive impairments in the passive avoidance test and the Y-maze test (P <0.05), and also reduced escape latency during training in the Morris water maze test (P <0.05). Moreover, swimming times and distances within the target zone of the Morris water maze were greater in the nodakenin-treated group than in the scopolamine-treated group (P <0.05). In an in vitro study, nodakenin was found to inhibit acetylcholinesterase activity in a dose-dependent manner (IC50 =84.7 μM). In addition, nodakenin was also found to inhibit acetylcholinesterase activity for 6 h in an ex-vivo study. These results suggest that nodakenin may be a useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, via the enhancement of cholinergic signaling. [Copyright &y& Elsevier]

Abstract: Matrix metalloproteinases (MMPs) are the proteases involved in the degradation of the extracellular matrix. MMP-1 is thought to be one of the key enzymes acting in fibrolysis, a process closely related to tissue remodeling. In this study, we found that emodin, an anthraquinone which has been isolated from the rhizome of Rheum palmatum, significantly inhibited TNF α-induced MMP-1 gene expression in a concentration-dependent manner. Therefore, we have attempted to characterize the inhibitory mechanism of emodin in TNF α-induced MMP-1 expression. Emodin was determined to inhibit TNF α-induced activation of AP-1 promoter, an important nuclear transcription factor in MMP-1 expression. Additionally, we detected that emodin suppressed the TNF α-induced phosphorylation of two mitogen-activated protein kinases, extracellular signal-regulated protein kinase and c-Jun N-terminal kinase, but it did not suppress the TNF α-induced phosphorylation of p38 kinase. In a consistent result, the TNF α-induced MMP-1 expression was inhibited by PD98059 (MEK/ERK inhibitor) and SP600125 (JNK inhibitor), but was not inhibited by SB203580, a p38 MAPK inhibitor. Taken together, these results show that emodin suppresses TNF α-induced MMP-1 expression through the inhibition of the AP-1 signaling pathway. [Copyright &y& Elsevier]

Abstract: Dehydroevodiamine is a major bioactive quinazoline alkaloid isolated from Evodiae Fructus. We investigated the anti-inflammatory properties of dehydroevodiamine in RAW 264.7 murine macrophages. The results indicated that dehydroevodiamine inhibited the expression of LPS-induced iNOS and COX-2 proteins and suppressed also their mRNAs from RT-PCR experiment on RAW 264.7 cells. Furthermore, this compound inhibited the level of LPS-stimulated prostaglandin E2 (PGE2) and LPS-induced nuclear factor-kappa B (NF-κB). Therefore, we suggested that the effect of dehydroevodiamine-mediated inhibition of the expression LPS-induced iNOS and COX-2 genes is due to under the suppression of NF-κB activation in the transcriptional level. [Copyright &y& Elsevier]

Abstract: In the present study, we investigated antiinflammatory effects of six flavonoids isolated from the rhizomes of Belamcanda chinensis (Iridaceae) in RAW 264.7 macrophages. The results indicated that irigenin concentration dependently inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin (PG) E2 production. Furthermore, this compound inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 proteins and mRNAs without an appreciable cytotoxic effect. Treatment of the transfectant RAW 264.7 cells with irigenin reduced the level of nuclear factor-κB (NF-κB) activity, also effectively lowered NF-κB binding measured by electrophoretic mobility shift assay (EMSA), which was associated with decreased p65 protein levels in the nucleus. On the basis of the above data, we suggest that the effect of irigenin in decreasing LPS-induced NO and PGE2 synthesis is due to diminish the mRNA and protein expression of iNOS and COX-2, respectively, also may be due to under the suppression of NF-κB activation. Therefore, irigenin isolated from the rhizomes of Belamcanda chinensis could be offered as a leading compound for antiinflammation. [Copyright &y& Elsevier]

Abstract: Saponins are glycosidic compounds present in many edible and inedible plants. They exhibit potent biological activities in mammalian systems, including several beneficial effects such as anti-inflammation and immunomodulation. In this study, we investigated the effects of seven platycodin saponins on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase II (COX-2) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. We found that 2ʺ-O-acetyl polygalacin D (S1), platycodin A (S2), platycodin D (S3), and polygalacin D (S6) inhibited LPS-induced NO production in a concentration-dependent manner. Furthermore, these compounds inhibited the expression of LPS-induced iNOS and COX-2 protein and mRNA without an appreciable cytotoxic effect on RAW 264.7 macrophages, and could suppress induction by LPS of pro-inflammatory cytokines such as prostaglandin E2 (PGE2). Treatment with these compounds of RAW 264.7 cells transfected with a reporter construct indicated a reduced level of LPS-induced nuclear factor-κB (NF-κB) activity and effectively lowered NF-κB binding as measured by electrophoretic mobility shift assay (EMSA). The suppression of NF-κB activation appears to occur through the prevention of inhibitor κB (IκB) degradation. In vivo, platycodin saponin mixture (PS) and S3 protected mice from the lethal effects of LPS. The 89% lethality induced by LPS/galactosamine was reduced to 60% and 50% when PS and S3, respectively, were administered simultaneously with LPS. These results suggest that the main inhibitory mechanism of the platycodin saponins may be the reduction of iNOS and COX-2 gene expression through blocking of NF-κB activation. [Copyright &y& Elsevier]

5-Fluorouracil (5-FU)-induced intestinal mucositis (IM) is one of the most common oncological problem. It involves serious clinical consequences such as diarrhea, erythematous lesions of mucosa, and eventually development of ulcers accompanied by severe pain. The aim of the present study was to demonstrate the mucoprotective effects of Saikosaponin-A in 5-FU-induced intestinal mucositis in mice. Mucositis was induced in BALB/c mice by intraperitoneal injection of 5-FU (50 mg/kg/day) for three consecutive days and IM was assessed by both behavioral and histochemical analysis. While, Saikosaponin-A (1, 5, 10 mg/kg/day) was administered 1 h before 5-FU injection for consecutive seven days. Pre-treatment of Saikosaponin-A significantly ameliorated the severity of mucositis reflected as food intake, body weight loss, severity of diarrhea and mortality rate in a dose depended manner as compared to mice treated with 5-FU. Moreover, histopathological analysis furthered reinforced the mucoprotective potential of Saikosaponin-A against 5-FU-induced intestinal abnormalities referred as villus atrophy, mitotic crypt stem cells damage, inflammatory cells infiltration, vacuolization and edema. Furthermore, Saikosaponin-A administration strongly inhibited pro-inflammatory mediators (TNF-α, COX-2, IL-1β and IL-6) and apoptotic markers (p-JNK, Casp-3). Saikosaponin-A pre-treatment significantly reduced the production of nitric oxide (NO) in intestinal tissue, inhibited acetic acid-induced Evans blue vascular permeability. The Siaikosaponin-A treatment markedly enhanced the anti-oxidants enzymes (Nrf2, HO-1, SOD, GSH, GST and Catalase), while decreased the oxidative stress markers i.e. Malonaldehde (MDA). Hence, these data suggest that Saikosaponin-A maybe a potential candidate for the treatment of chemotherapy-induced intestinal mucositis. [ABSTRACT FROM AUTHOR]