• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.1
• /
• pp.53-61
• /
• 2018

Ethyl linoleate is an unsaturated fatty acid used in many cosmetics for its various attributes, such as antibacterial and anti-inflammatory properties and clinically proven to be an effective anti-acne agent. In this study, we investigated the effect of ethyl linoleate on the melanogenesis and the mechanism underlying its action on melanogenesis in B16F10 murine melanoma cells. Our results revealed that ethyl linoleate significantly inhibited melanin content and intracellular tyrosinase activity in ${\alpha}$-MSH-induced B16F10 cells, but it did not directly inhibit activity of mushroom tyrosinase. Ethyl linoleate inhibited the expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase related protein 1 (TRP1) in governing melanin pigment synthesis. We observed that ethyl linoleate inhibited phosphorylation of Akt and glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$) and reduced the level of ${\beta}-catenin$, suggesting that ethyl linoleate inhibits melanogenesis through $Akt/GSK3{\beta}/{\beta}-catenin$ signal pathway. Therefore, we propose that ethyl linoleate may be useful as a safe whitening agent in cosmetic and a potential therapeutic agent for reducing skin hyperpigmentation in clinics.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.1
• /
• pp.121-126
• /
• 2020

The ezrin-radixin-moesin (ERM) proteins are a family of membrane-associated proteins known to play roles in cell-shape determination as well as in signaling pathways. We have previously shown that amphetamine decreases phosphorylation levels of these proteins in the nucleus accumbens (NAcc), an important neuronal substrate mediating rewarding effects of drugs of abuse. In the present study, we further examined what molecular pathways may be involved in this process. By direct microinjection of LY294002, a PI3 kinase inhibitor, or of S9 peptide, a proposed GSK3β activator, into the NAcc core, we found that phosphorylation levels of ERM as well as of GSK3β in this site are simultaneously decreased. These results indicate that ERM proteins are under the regulation of Akt-GSK3β signaling pathway in the NAcc core. The present findings have a significant implication to a novel signal pathway possibly leading to structural plasticity in relation with drug addiction.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.48 no.1
• /
• pp.11-24
• /
• 2022

It has been reported that the ethanolic extract of the root of Piper methysticum (P. methysticum) inhibits melanogenesis in melanocyte stimulating hormone (MSH)-activated B16 melanoma cells. Flavokawain B (FKB) and Flavokawain C (FKC) isolated from this extract have been found to inhibit melanin production based on anti-melanogenesis activity. This study was designed to find out the inhibition and its process of FKB and FKC on melanin synthesis in melan-a melanocytes. FKB and FKC inhibited melanogenesis at 10 μM, 5 μM respectively in melan-a melanocytes. However, they did not inhibit extracellular tyrosinase activity from melan-a melanocytes. FKB reduced the protein level of tyrosinase (Tyr), tyrosinase-related protein 1 (TRP-1), tyrosinase-related protein 2 (TRP-2), microphthalmia-associated transcription factor (MITF) and the mRNA level of Tyr and TRP-1. FKC reduced the protein level of TRP-2 and MITF and the mRNA level of TRP-1 and Tyr. The reduced expression of Tyr and TRP-1 might be resulted from the decreased MITF which regulates major melanogenic proteins. However, since the mRNA expression of MITF did not change by FKB and FKC treatment, the effects of FKB and FKC on extracellular signal regulating kinase (ERK)/AKT phosphorylation, known to regulate the degradation of MITF, were confirmed. FKB and FKC significantly increased the phosphorylation of ERK1/2, not in AKT. These results suggest that FKB and FKC may be helpful as a potential depigmenting agent for various hyper-pigmentary disorders.

• Fisheries and Aquatic Sciences
• /
• v.26 no.2
• /
• pp.133-144
• /
• 2023

Auranofin is a US Food and Drug Administration (FDA)-approved anti-arthritis medication that functions as a thioredoxin reductase inhibitor. Spermidine, a polyamine present in marine algae, can exert various physiological functions. Herein, we examined the synergistic anticancer activity of auranofin and spermidine in hepatocellular carcinoma (HCC). Combined treatment with auranofin and spermidine suppressed cell viability more efficiently than either treatment alone in HCC Hep3B cells. The isobologram plotted by calculating the half maximal inhibitory concentration (IC₅₀) values of each drug indicated that the two drugs exhibited a synergistic effect. Based on the analysis of annexin V and cell cycle distribution, auranofin and spermidine markedly induced apoptosis in Hep3B cells. Moreover, auranofin and spermidine increased mitochondria-mediated apoptosis by promoting mitochondrial membrane potential (Δψm) loss. Auranofin and spermidine significantly increased reactive oxygen species (ROS) production in Hep3B cells, and the blocking ROS suppressed apoptosis induced by spermidine and auranofin. In addition, auranofin and spermidine reduced the expression of phosphorylated phosphatidylinositol-3 kinase (PI3K) and protein kinase B (Akt), and PI3K inhibitor accelerated auranofin- and spermidine-induced apoptosis. Using ROS scavenger and PI3K inhibitor, we revealed that ROS acts upstream of auranofin- and spermidine-induced apoptosis. Collectively, our study suggests that combination treatment with auranofin and spermidine could afford synergistic anticancer activity via ROS overproduction and reduced PI3K/Akt signaling pathway.

• Nutrition Research and Practice
• /
• v.11 no.3
• /
• pp.180-189
• /
• 2017

BACKGROUND/OBJECTIVES: Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism. MATERIALS/METHODS: Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha ($HNF-1{\alpha}$), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta ($GSK-3{\beta}$) expression levels. The ${\alpha}-glucosidase$ inhibitory activities of acarbose and CMW were evaluated by absorbance measurement. RESULTS: CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through $HNF-1{\alpha}$ expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and $GSK-3{\beta}$, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of ${\alpha}-glucosidase$ inhibitory activity than that from acarbose. CONCLUSION: CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.5
• /
• pp.552-561
• /
• 2017

This study aimed to investigate glucose uptake mechanisms and metabolic mechanisms for absorbed glucose in HepG2 cells treated with Acanthopanax senticosus water extract (ASW). A colorimetric assay kit was used to measure polyphenol content, glucokinase (GK) activity, glucose uptake, glucose consumption in cell culture medium, and glycogen content. RT-PCR and western blotting were performed to examine changes in the expression levels of glucose transporter 2 (GLUT2), hepatocyte nuclear factor $1{\alpha}$ ($HNF-1{\alpha}$), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phospho-AMP-activated protein kinase (AMPK), phosphoenolpyruvate carboxykinase, GK, and glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$). Increased glucose uptake upon ASW treatment was confirmed to result from increased expression of $HNF-1{\alpha}$, which is one of the transcription factors acting on the GLUT2 promoter. From the measurements of GK activity, we observed that ASW had an effect on glucose phosphorylation, and we also confirmed that increased AMPK phosphorylation promoted glycolysis and suppressed gluconeogenesis. We confirmed that the increase in glycogen upon ASW treatment was induced by activation of Akt by PI3k, followed by phosphorylation of $GSK3{\beta}$. This study demonstrates that ASW activates glucose metabolic mechanisms in liver cells and is therefore a potential candidate to alleviate diabetes.

• Nutrition Research and Practice
• /
• v.7 no.6
• /
• pp.423-429
• /
• 2013

Luteolin is a flavonoid found in abundance in celery, green pepper, and dandelions. Previous studies have shown that luteolin is an anti-inflammatory and anti-oxidative agent. In this study, the anti-inflammatory capacity of luteolin and one of its glycosidic forms, luteolin-7-O-glucoside, were compared and their molecular mechanisms of action were analyzed. In lipopolysaccharide (LPS)-activated RAW 264.7 cells, luteolin more potently inhibited the production of nitric oxide (NO) and prostaglandin E2 as well as the expression of their corresponding enzymes (inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) than luteolin-7-O-glucoside. The molecular mechanisms underlying these effects were investigated to determine whether the inflammatory response was related to the transcription factors, nuclear factor (NF)-${\kappa}B$ and activator protein (AP)-1, or their upstream signaling molecules, mitogen-activated protein kinases (MAPKs) and phosphoinositide 3-kinase (PI3K). Luteolin attenuated the activation of both transcription factors, NF-${\kappa}B$ and AP-1, while luteolin-7-O-glucoside only impeded NF-${\kappa}B$ activation. However, both flavonoids inhibited Akt phosphorylation in a dose-dependent manner. Consequently, luteolin more potently ameliorated LPS-induced inflammation than luteolin-7-O-glucoside, which might be attributed to the differentially activated NF-${\kappa}B$/AP-1/PI3K-Akt pathway in RAW 264.7 cells.

• Archives of Pharmacal Research
• /
• v.27 no.7
• /
• pp.683-692
• /
• 2004

Curcumin (diferuloylmethane) is a major naturally-occurring polyphenol of Curcuma species, which is commonly used as a yellow coloring and flavoring agent in foods. Curcumin has shown anti-carcinogenic activity in animal models. Curcumin possesses anti-inflammatory activity and is a potent inhibitor of reactive oxygen-generating enzymes such as lipoxygenase/cyclooxygenase, xanthine dehydrogenase/oxidase and inducible nitric oxide synthase; and an effective inducer of heme oxygenase-1. Curcumin is also a potent inhibitor of protein kinase C(PKC), EGF(Epidermal growth factor)-receptor tyrosine kinase and LĸB kinase. Subsequently, curcumin inhibits the activation of NF(nucleor factor)KB and the expressions of oncogenes including c-jun, c-fos, c-myc, NIK, MAPKs, ERK, ELK, PI3K, Akt, CDKs and iNOS. It is proposed that curcumin may suppress tumor promotion through blocking signal transduction path-ways in the target cells. The oxidant tumor promoter TPA activates PKC by reacting with zinc thiolates present within the regulatory domain, while the oxidized form of cancer chemopreventive agent such as curcumin can inactivate PKC by oxidizing the vicinal thiols present within the catalytic domain. Recent studies indicated that proteasome-mediated degradation of cell proteins playa pivotal role in the regulation of several basic cellular processes including differentiation, proliferation, cell cycling, and apoptosis. It has been demonstrated that curcumin-induced apoptosis is mediated through the impairment of ubiquitin-proteasome pathway. Curcumin was first biotransformed to dihydrocurcumin and tetrahydrocurcumin and that these compounds subsequently were converted to monoglucuronide conjugates. These results suggest that curcumin-glucuronide, dihydrocurcumin-glucuronide, tetrahydrocurcumin-glucuronide and tetrahydrocurcumin are the major metabolites of curcumin in mice, rats and humans.

• Journal of Ginseng Research
• /
• v.42 no.4
• /
• pp.496-503
• /
• 2018

Background: Korean ginseng (Panax ginseng) plays an anti-inflammatory role in a variety of inflammatory diseases such as gastritis, hepatitis, and colitis. However, inflammation-regulatory activity of the calyx of the P. ginseng berry has not been thoroughly evaluated. To understand whether the calyx portion of the P. ginseng berry is able to ameliorate inflammatory processes, an ethanolic extract of P. ginseng berry calyx (Pg-C-EE) was prepared, and lipopolysaccharide-activated macrophages and HEK293 cells transfected with inflammation-regulatory proteins were used to test the anti-inflammatory action of Pg-C-EE. Methods: The ginsenoside contents of Pg-C-EE were analyzed by HPLC. Suppressive activity of Pg-C-EE on NO production, inflammatory gene expression, transcriptional activation, and inflammation signaling events were examined using the Griess assay, reverse transcription-polymerization chain reaction, luciferase activity reporter gene assay, and immunoblotting analysis. Results: Pg-C-EE reduced NO production and diminished mRNA expression of inflammatory genes such as cyclooxygenase-2, inducible NO synthase, and tumor necrosis factor-${\alpha}$ in a dose-dependent manner. This extract suppressed luciferase activity induced only by nuclear factor-${\kappa}B$. Interestingly, immunoblotting analysis results demonstrated that Pg-C-EE reduced the activities of protein kinase B (AKT)1 and AKT2. Conclusion: These results suggest that Pg-C-EE may have nuclear-factor-${\kappa}B$-targeted anti-inflammatory properties through suppression of AKT. The calyx of the P. ginseng berry is an underused part of the ginseng plant, and development of calyx-derived extracts may be useful for treatment of inflammatory diseases.

• The Korean Journal of Physiology and Pharmacology
• /
• v.25 no.2
• /
• pp.147-157
• /
• 2021

Coronary microembolization (CME) is associated with cardiomyocyte apoptosis and cardiac dysfunction. Puerarin confers protection against multiple cardiovascular diseases, but its effects and specific mechanisms on CME are not fully known. Hence, our study investigated whether puerarin pretreatment could alleviate cardiomyocyte apoptosis and improve cardiac function following CME. The molecular mechanism associated was also explored. A total of 48 Sprague-Dawley rats were randomly divided into CME, CME + Puerarin (CME + Pue), sham, and sham + Puerarin (sham + Pue) groups (with 12 rats per group). A CME model was established in CME and CME + Pue groups by injecting 42 ㎛ microspheres into the left ventricle of rats. Rats in the CME + Pue and sham + Pue groups were intraperitoneally injected with puerarin at 120 mg/kg daily for 7 days before operation. Cardiac function, myocardial histopathology, and cardiomyocyte apoptosis index were determined via cardiac ultrasound, hematoxylin-eosin (H&E) and hematoxylin-basic fuchsin-picric acid (HBFP) stainings, and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. Western blotting was used to measure protein expression related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway. We found that, puerarin significantly ameliorated cardiac dysfunction after CME, attenuated myocardial infarct size, and reduced myocardial apoptotic index. Besides, puerarin inhibited cardiomyocyte apoptosis, as revealed by decreased Bax and cleaved caspase-3, and up-regulated Bcl-2 and PI3K/Akt/GSK-3β pathway related proteins. Collectively, puerarin can inhibit cardiomyocyte apoptosis and thus attenuate myocardial injury caused by CME. Mechanistically, these effects may be achieved through activation of the PI3K/Akt/GSK-3β pathway.