Sung Ok Kim

Water‑extracted plum (Prunus salicina L. cv. Soldam) attenuates adipogenesis in murine 3T3‑L1 adipocyte cells through the PI3K/Akt signaling pathway

The objective of the present study was to evaluate the effects of water-extracted plum (WEP) on adipocyte differentiation, adipogenesis and inflammation in differentiated 3T3-L1 adipocyte cells. WEP was assessed for basic analyses, including high-performance liquid chromatography, total phenolic and flavonoid content and antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) assays] in vitro. Moreover, the cell viability was measured using an MTT assay. Adipogenesis and lipid accumulation in 3T3-L1 adipocytes was investigated using Oil Red O staining, and the expression of genes and proteins associated with adipogenesis and lipolysis were examined by reverse transcription polymerase chain reaction and western blotting. In addition, sulforaphane using a positive control was performed simultaneously. The WEP significantly suppressed adipocyte differentiation and lipid accumulation in differentiated adipocytes without cytotoxicity. WEP resulted in direct anti-obesity effects through the modulation of adenosine monophosphate-activated protein kinase, sterol regulatory element-binding protein 1c, cytidine-cytidine-adenosine-adenosine-thymidine/enhancer binding protein α and peroxisome proliferator-activated receptor γ. These regulations of molecular expressions were significantly activated via the phosphoinositide 3-kinase/Akt pathway. Moreover, these results provide potential anti-adipogenic effects of WEP and may have potential as a natural agent for the prevention and improvement of obesity.

Anti‑inflammatory effects of Daehwangmokdantang, a traditional herbal formulation, in lipopolysaccharide‑stimulated RAW 264.7 macrophages

Daehwangmokdantang (DHMDT) is a traditional polyherbal formulation that has known antidiarrheal and anti-inflammatory activities. However, the underlying mechanisms of these activities are poorly understood. In the present study, the inhibitory effects of DHMDT on the production of proinflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages were investigated. The inhibitory effects of DHMDT on LPS-induced nitric oxide (NO), prostaglandin (PG)E2, tumor necrosis factor (TNF)-α and interleukin (IL)-1β production were examined using Griess reagent and ELISA detection kits. The effects of DHMDT on the expression of inducible NO synthase (iNOS), cyclooxygenase (COX)-2, IL-1β and TNF-α, and their upstream signal proteins, including nuclear factor (NF)-κB, mitogen-activated protein kinases (MAPKs) and RAC-α serine/threonine-protein kinase (Akt), a phosphatidylinositol 3-kinase (PI3K) downstream effector, were investigated using western blotting and immunofluorescence staining. The results revealed the pretreatment with DHMDT significantly inhibited the LPS-induced production of NO, PGE2, TNF-α, and IL-1β, and expression of iNOS, COX-2 TNF-α, and IL-1β, without any significant cytotoxicity. DHMDT also efficiently prevented the translocation of the NF-κB subunit p65 into the nucleus by interrupting the activation of the upstream mediator inhibitor of NF-κB kinase α/β. Furthermore, the anti-inflammatory effects of DHMDT were associated with the suppression of LPS-induced phosphorylation of Akt and MAPKs in RAW 264.7 macrophages. Therefore, the results of the present study indicate that DHMDT exhibited anti-inflammatory activity via the inhibition of proinflammatory mediators and cytokines, in which the inactivation of NF-κB, PI3K/Akt, and MAPKs may be involved. These results suggest that DHMDT may be a potential anti-inflammatory drug candidate.

Ethanol extracts of Aster yomena (Kitam.) Honda inhibit adipogenesis through the activation of the AMPK signaling pathway in 3T3-L1 preadipocytes

The leaves of Aster yomena (Kitam.) Honda have long been used as a traditional herb for treating disorders including coughs, asthma, and insect bites. According to recent studies, A. yomena leaf extracts have several pharmacological properties, including anti-inflammatory, antioxidant, and anti-asthmatic activities. However, little information is available regarding their anti-obesity effect. In this study, we investigated the inhibitory effect of the ethanol extracts of A. yomena leaves (EEAY) on adipocyte differentiation and adipogenesis using 3T3-L1 preadipocytes. When 3T3-L1 preadipocytes were treated with various concentrations of EEAY (ranging from non-toxic), the number of lipid droplets, lipid content, and triglyceride production, the typical characteristics of adipocytes, were suppressed in a concentration-dependent manner. During this process, EEAY significantly reduced the expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein α and β, and sterol regulatory element-binding protein-1c. In addition, EEAY was also found to potently inhibit the expression of adipocyte-specific genes, including adipocyte fatty acid-binding protein and leptin. In particular, EEAY treatment effectively enhanced the activation of the AMP-activated protein kinase (AMPK) signaling pathway; however, the co-treatment with compound C, an inhibitor of AMPK, significantly restored the EEAY-induced inhibition of pro-adipogenic transcription factors and adipocyte-specific genes. These results indicate that EEAY may exert an anti-obesity effect by controlling the AMPK signaling pathway, suggesting that the leaf extract of A. yomena may be a potential anti-obesity agent.

An ethanol extract of Aster yomena (Kitam.) Honda inhibits lipopolysaccharide-induced inflammatory responses in murine RAW 264.7 macrophages

Aster yomena (Kitam.) Honda has been widely used as a traditional herbal medicine for centuries to treat cough, asthma, insect bites, etc. Recent reports indicate that A. yomena possesses a wide spectrum of pharmacological activities; however, few experiments have described its anti-inflammatory properties. The present study examined the anti-inflammatory effects of an ethanol extract of A. yomena leaves (EEAY) on lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages. Treatment with EEAY significantly reduced the secretion of pro-inflammatory molecules, such as nitric oxide and interleukin-1β, in LPS-stimulated RAW 264.7 cells, without incurring any significant cytotoxicity. These protective effects were accompanied by a marked reduction in the expression of regulatory genes at the transcription level. Treatment with EEAY also inhibited the DNA-binding activity of nuclear factor-κB (NF-κB) by suppression of nuclear translocation of NF-κB and by degradation of the inhibitor of NF-κB; these effects were associated with suppression of the phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase signaling pathways. The EEAY treatment also potently suppressed LPS-induced toll like receptor (TLR) 4 expression and attenuated the binding of LPS to the macrophage cell surface. In addition, EEAY treatment markedly inhibited LPS-induced accumulation of intracellular reactive oxygen species in RAW 264.7 macrophages. Therefore, the inhibitory effects of EEAY on LPS-stimulated inflammatory responses in RAW 264.7 macrophages were apparently associated with suppression of the TLR-mediated NF-κB signaling pathway. More work is needed to fully understand the critical role and clinical usefulness of EEAY treatment, but the findings of the present study provide some insights into the potential of EEAY as a therapeutic agent for treatment of inflammatory disorders.

Ethanol extract of Kalopanax septemlobus leaf inhibits HepG2 human hepatocellular carcinoma cell proliferation via inducing cell cycle arrest at G1 phase.

OBJECTIVE To investigate the effects of an ethanol extract of Kalopanax septemlobus (Thunb.) Koidz. leaf (EEKS) on cell proliferation in human hepatocellular carcinoma cells and its mechanisms of action. METHODS Cells were treated with EEKS and subsequently analyzed for cell proliferation and flow cytometry analysis. Expressions of cell cycle regulators were determined by reverse transcriptase polymerase chain reaction analysis and Western blotting, and activation of cyclin-associated kinases studied using kinase assays. RESULTS The EEKS suppressed cell proliferation in both HepG2 and Hep3B cells, but showed a more sensitive anti-proliferative activity in HepG2 cells. Flow cytometry analysis revealed an association between the growth inhibitory effect of EEKS and with G1 phase cell cycle arrest in HepG2 cells, along with the dephosphorylation of retinoblastoma protein (pRB) and enhanced binding of pRB with the E2F transcription factor family proteins. Treatment with EEKS also increased the expression of cyclin-dependent kinase (CDK) inhibitors, such as p21WAF1/CIP1 and p27KIP1, without any noticeable changes in G1 cyclins and CDKs (except for a slight decrease in CDK4). Treatment of HepG2 cells with EEKS also increased the binding of p21 and p27 with CDK4 and CDK6, which was paralleled by a marked decrease in the cyclin D- and cyclin E-associated kinase activities. CONCLUSIONS Overall, our findings suggest that EEKS may be an effective treatment for liver cancer through suppression of cancer cell proliferation via G1 cell cycle arrest. Further studies are required to identify the active compounds in EEKS.