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In this study, a value-based children's financial education program was developed focusing on the values of each financial management area needed for children. According to 'quasi-experimental design - nonequivalent control group design', an experimental group and a control group were formed for children in the lower grades of elementary school, and a value-based child financial education program was executed, and then the program was applied to children's personal financial management. The effect on the value propensity for each area was evaluated. As a result of the quantitative evaluation, it was confirmed that the 8 values of the children in the experimental group were significantly improved compared to the children of the control group, so this program was effective in enhancing the values of each of the 8 areas of personal financial management needed for children. In addition, the children in the experimental group showed significant improvement compared to the children in the control group in the cognitive, justice, and psychodynamic levels of values. It has also been found to be effective in enhancing as a result of the qualitative evaluation, various positive changes were found in the cognitive, affective, and psycho-dynamic dimensions about the values of each financial management area for children. From a positive perspective, it was found that it plays a useful role in cultivating the values of each area of positive personal financial management.

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Food-derived bioactive peptides (BPs) have received considerable attention as postbiotics for human gut health. Here we used a genomics-based semirational approach to expand the postbiotic potential of collagen peptides (CPs) produced from probiotic fermentation.

Benzo[a]pyrene-7,8-diol-9,10-epoxide (B[a]PDE) has been reported to cause various pathological lesions in humans via activation of the aryl hydrocarbon receptor (AhR) pathway. However, the molecular mechanism by which B[a]PDE regulates signaling pathways during skin aging remains unclear. The present study investigated the effects of B[a]PDE on the expression of matrix metalloproteinase-1 (MMP-1), which is a major enzyme responsible for collagen damage, and its regulation of skin aging-related signaling pathways in HaCaT human keratinocyte cells. MMP-1 expression was increased by B[a]PDE treatment, and mitogen-activated protein kinase (MAPK) inhibitors suppressed B[a]PDE-induced MMP-1 expression. Furthermore, a-naphthoflavone (a-NF, AhR antagonist), PP2 (c-Src inhibitor), and gefitinib (EGFR inhibitor) attenuated the B[a]PDE-induced phosphorylation of and p38 and their upstream kinases such as c-Raf, MEK, and MKK3/6. These results suggest that AhR, c-Src, and epidermal growth factor receptor (EGFR) activations are necessary for B[a]PDE-induced MMP-1 upregulation by modulation of MAPK pathway activation. B[a]PDE also stimulates the phosphorylation of ERK via c-Src-dependent EGFR transactivation. These results demonstrate a novel mechanism by which B[a]PDE induces MMP-1 expression through the activation of AhR, c-Src, and EGFR in non-genetic pathways. Thus, it is indicated that the molecular mechanisms of MMP-1 expression by B[a]PDE-activated AhR play an important role in promoting skin aging.

Bioactive peptides (BPs) play key roles in regulating cellular metabolism, and are therefore of special interest to the nutraceutical and pharmaceutical industries. Protein digestion is a major rou...

The extremely thermophilic eubacterium Fervidobacterium islandicum AW-1 produces low molecular weight (LMW; < 1 kDa) keratin peptides (KPs) from poultry feathers at 70°C. However, detection and quantification of feather hydrolysate-derived peptides is needed for optimizing fermentation and down-stream processes. Herein, we developed a large-scale fermentation and purification of skin anti-aging LMW KPs from recalcitrant feathers using fluorescence-based quantification of N-terminal prolinecontaining KPs derivatized with 3,4-dihydroxybenzoic acid to yield fluorescent adducts. Fluorescent products were correlated with bioactive KP concentrations in keratin fractions and cosmetic formulations. Subsequent anaerobic fermentative keratinolysis and large-scale purification achieved 4.4 g/L LMW KPs from 8 g/L native feathers in a 5 L batch bioreactor, generating 0.8 g/L purified MMP-1 suppressive KPs (yield = 1.2%). This demonstrated the feasibility of industrial-scale anaerobic feather digestion and purification of LMW KPs to produce skin anti-aging peptides from keratin hydrolysates in a more environmentally sustainable manner.

Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease. Environmental sanitization, modern lifestyles, advanced medicines, ethnic origins, host genetics and immune systems, mucosal barrier function, and the gut microbiota have been delineated to explain how they cause mucosal inflammation. However, the pathogenesis of IBD and its therapeutic targets remain elusive. Recent studies have highlighted the importance of the human gut microbiota in health and disease, suggesting that the pathogenesis of IBD is highly associated with imbalances of the gut microbiota or alterations of epithelial barrier function in the gastrointestinal (GI) tract. Moreover, diet-induced alterations of the gut microbiota in the GI tract modulate immune responses and perturb metabolic homeostasis. This review summarizes recent findings on IBD and its association with diet-induced changes in the gut microbiota; furthermore, it discusses how diets can modulate host gut microbes and immune systems, potentiating the impact of personalized diets on therapeutic targets for IBD.

Background Hyaluronic acid (HA) is an important factor in skin hydration maintenance. In mammalian keratinocytes, hyaluronan synthase 2 (HAS2) is a critical enzyme in HA production. Therefore, the promotion of HAS2 expression in keratinocytes may be a strategy for maintaining skin moisture. Objective The aim was to determine the skin hydration effect and regulatory mechanisms of 3,6-anhydro-L-galactose (L-AHG), a main component of red macroalgal carbohydrates in human keratinocytes. Methods L-AHG was applied to an immortalized human epidermal keratinocyte cell line (HaCaT cells). HA production, HAS2 protein and mRNA levels, and the activation of the signaling pathways involved in HAS2 expression were measured. HA levels were also evaluated for three dimensional (3D) reconstructed human skin. Results Our results suggest that L-AHG upregulates HA production and may enhance HAS2 expression by activating EGFR-mediated ERK, PI3K/Akt, and STAT3 signaling pathways. We confirmed that L-AHG activated the AMPKα signaling pathway which in turn could regulate HAS2 expression in HaCaT cells. The effects of L-AHG on HA production were observed in the 3D reconstructed human skin model. Conclusion Our results suggest that L-AHG may enhance skin moisture retention by increasing HA synthesis in human epidermal keratinocytes.

Inhibition of matrix metalloproteinases (MMPs), which degrade collagen and elastin in the dermis of normal skin, is a key strategy for anti-skin aging. In this study, we identified five low-molecular-weight (LMW,1 kDa) MMP-1-suppressive peptides in feather keratin hydrolysate (FKH) obtained by anaerobic digestion with an extremophilic bacterium. FKH was first subjected to ultrafiltration, followed by size-exclusion chromatography and liquid chromatography/electrospray ionization tandem mass spectrometry analysis. Chemically synthesized peptides identical to the sequences identified suppressed MMP expression in human dermal fibroblasts (HDFs). To investigate the impact of the MMP-1-suppressive peptides on the signaling pathway, we performed antibody array phosphorylation profiling of HDFs. The results suggested that the peptide GGFDL regulates ultraviolet-B-induced MMP-1 expression by inhibiting mitogen-activated protein kinases and nuclear factor κB signaling pathways as well as histone modification. Thus, LMW feather keratin peptides could serve as novel bioactive compounds to protect the skin against intrinsic and extrinsic factors.

Marine algae are considered to be an abundant sources of bioactive compounds with cosmeceutical potential. Recently, a great deal of interest has focused on the health-promoting effects of marine bioactive compounds. Carbohydrates are the major and abundant constituent of marine algae and have been utilized in cosmetic formulations, as moisturizing and thickening agents for example. In addition, marine carbohydrates have been suggested as promising bioactive biomaterials for their various properties beneficial to skin, including antioxidant, anti-melanogenic and skin anti-aging properties. Therefore, marine algae carbohydrates have potential skin health benefits for value-added cosmeceutical applications. The present review focuses on the various biological capacities and potential skin health benefits of bioactive marine carbohydrates.

본 연구는 rutin 및 rutin 대사체인 DHPAA, HPAA, DHT, HVA가 버섯 유래 tyrosinase 활성과 마우스 피부표피 세포주인 JB6 P+ 세포의 증식에 미치는 영향에 대해 살펴보았다. HVA가 버섯유래 티로시나제 저해활성이 가장 우수한 것으로 관찰되었으며, DHPAA, HPAA, rutin, DHT 순서로 저해효능을 나타내었다. DHT를 제외한 rutin 및 rutin 대사체들 모두 $100{\mu}M$ 까지 세포 독성이 관찰되지 않은 것으로 관찰되었으며, DHT는 50 또는 $100{\mu}M$ 에서 세포증식을 저해하였으나 그 이하의 농도에서는 세포독성을 유도하지 않았다. 따라서 본 연구결과, rutin 대사체 모두 세포 독성이 없는 수준에서 버섯 유래 티로시나제 활성을 효과적으로 억제하였으므로, 앞으로 미백제제로 활용될 수 있을 것으로 기대된다. 【The aim of this research was to investigate the whitening effects of rutin and rutin metabolites including 3,4-dihydroxyphenyl acetic acid (DHPAA), 3-hydroxyphenyl acetic acid (HPAA), 3,4-dihydroxytolene (DHT) and homovanillic acid (HVA). The potent whitening effect of rutin and rutin metabolites were determined by mushroom tyrosinase inhibition assay and expressed as the half maximal inhibitory concentration ( $IC_{50}$ ) against tyrosinase activity in vitro. The HVA showed the highest inhibitory effect ( $IC_{50}=37.10{\mu}M$ ) of tyrosinase activity, followed by DHPAA ( $IC_{50}=45.87{\mu}M$ ), HPAA ( $IC_{50}=50.96{\mu}M$ ), rutin ( $IC_{50}=57.98{\mu}M$ ), and DHT ( $IC_{50}=66.09{\mu}M$ ), respectively. To evaluate cell cytotoxicity, MTT assay was performed with JB6 P+ mouse epidermal cells and expressed as a relative percentage of untreated control. The results showed that rutin and rutin metabolites had no cytotoxic effects on JB6 P+ cells up to $100{\mu}M$ except for DHT (up to $50{\mu}M$ ). These results suggests that rutin metabolites may be utilized as a potential tyrosinase inhibitors and the whitening agents for the future.】

Summary In summary, the rutin metabolite DHT significantly reduced EGF-induced neoplastic transformation in JB6 P+ cells. This inhibition was mediated mainly by blocking the Raf/MEK/ERK signaling pathway and subsequent suppression of AP-1 activities. DHT attenuated Raf-1 kinase activity by directly binding to Raf-1 in vitro and ex vivo. Taken together, these results suggest that Raf-1 may be a critical molecular target to suppress DHT- induced neoplastic transformation, which is mainly attributable to the chemopreventive potential of several foods containing rutin. Acknowledgments This research was supported by the Kyungpook National University Research Fund, 2009. References Alonso-Castro AJ, Dominguez F, Garcia-Carranca A. 2013. Rutin exerts antitumor effects on nude mice bearing SW480 tumor. Arch Med Res 44:346-351 Antonyak MA, Moscatello DK, Wong AJ. 1998. Constitutive activation of c-Jun N-terminal kinase by a mutant epidermal growth factor receptor. J Biol Chem 273:2817-2822Bode AM, Dong Z. 2005. Signal transduction pathways in cancer development and as targets for cancer prevention. Prog Nucleic Acid Res Mol Biol 79:237-297 Cheepala SB, Yin W, Syed Z, Gill JN, McMillian A, Kleiner HE, Lynch M, Loganantharaj R, Trutschl M, Cvek U, Clifford JL. 2009. Identification of the B-Raf/Mek/Erk MAP kinase pathway as a target for all-trans retinoic acid during skin cancer promotion. Mol Cancer 8:27 Choi KS, Kundu JK, Chun KS, Na HK, Surh YJ. 2014. Rutin inhibits UVB radiation-induced expression of COX-2 and iNOS in hairless mouse skin: p38 MAP kinase and JNK as potential targets. Arch Biochem Biophys 559:38-45.Dong Z, Birrer MJ, Watts RG, Matrisian LM, Colburn NH. 1994. Blocking of tumor promoter-induced AP-1 activity inhibits induced transformation in JB6 mouse epidermal cells. Proc Natl Acad Sci USA 91:609-613Garcia-Lafuente A, Guillamon E, Villares A, Rostagno MA, Martinez JA. 2009. Flavonoids as anti-inflammatory agents: implications in cancer and cardiovascular disease. Inflamm Res 58:537-552 Glasser G, Graefe EU, Struck F, Veit M, Gebhardt R. 2002. Comparison of antioxidative capacities and inhibitory effects on cholesterol biosynthesis of quercetin and potential meta-bolites. Phytomedicine 9:33-40 He Z, Cho YY, Liu G, Ma WY, Bode AM, Dong Z. 2003. p38 Mitogen-activated protein kinase regulation of JB6 Cl41 cell transformation promoted by epidermal growth factor. J Biol Chem 278:26435-26442 Huang C, Ma WY, Dawson MI, Rincon M, Flavell RA, Dong Z. 1997. Blocking activator protein-1 activity, but not acti-vating retinoic acid response element, is required for the antitumor promotion effect of retinoic acid. Proc Natl Acad Sci USA 94:5826-5830Huang CS, Ma WY, Young MR, Colburn N, Dong ZG. 1998. Shortage of mitogen-activated protein kinase is responsible for resistance to AP-1 transactivation and transformation in mouse JB6 cells. Proc Natl Acad Sci USA 95:156-161Ito S, Inoue S, Yamamoto Y, Fujita K. 1981. Synthesis and antitumor activity of cysteinyl-3,4-dihydroxyphenylalanines

Bioactive peptides contribute to various cellular processes including improved skin physiology. Hence, bioactive keratins have attracted considerable attention as active cosmetic ingredients for skin health. Here, we obtained low molecular weight (LMW) keratins from native chicken feathers by anaerobic digestion with an extremely thermophilic bacterium Fervidobacterium islandicum AW-1, followed by stepwise fractionation through ultrafiltration. To assess the effects of the feather keratins on skin health, we performed in vitro and ex vivo assays to investigate their inhibitory effects on matrix metalloproteinases (MMPs). As results, LMW feather keratins marginally inhibited collagenase, elastase, and radical scavenging activities. On the other hand, LMW feather keratins significantly suppressed the expression of ultraviolet B (UVB)-induced MMP-1 and MMP-13 in human dermal fibroblasts. Furthermore, phospho-kinase antibody array revealed that LMW feather keratins suppressed UVB-induced phosphorylation of Akts, c-Jun N-terminal kinases 1, p38 beta, and RSK2, but not ERKs in human dermal fibroblast. Overall, these results suggest that LMW feather keratins are potential candidates as cosmeceutical peptides for anti-skin aging.

We evaluated the effects of the two main kiwifruit cultivars (gold kiwifruit (GOK) and green kiwifruit (GRK)) and their active phenolic compound, quercetin, on H2O2-induced inhibition of gap-junction intercellular communication (GJIC) in WB-F344 rat liver epithelial cells. We found that both GOK and GRK protect WB-F344 cells from H2O2-induced inhibition of GJIC. The extracellular signal-regulated protein kinase 1/2 (ERK1/2)–connexin 43 (Cx43) signalling pathway is crucial for the regulation of GJIC, and both GOK and GRK blocked the H2O2-induced phosphorylation of Cx43 and ERK1/2 in WB-F344 cells. Quercetin alone attenuated the H2O2-mediated ERK1/2–Cx43 signalling pathway and consequently reversed H2O2-mediated inhibition of GJIC in WB-F344 cells. A free radical-scavenging assay using 1,1-diphenyl-2-picrylhydrazyl showed that the scavenging activity of quercetin was higher than that of a synthetic antioxidant, butylated hydroxytoluene, per mol, suggesting that the chemopreventive effect of quercetin on H2O2-mediated inhibition of ERK1/2–Cx43 signalling and GJIC may be mediated through its free radical-scavenging activity. Since the carcinogenicity of reactive oxygen species such as H2O2 is attributable to the inhibition of GJIC, GOK, GRK and quercetin may have chemopreventive potential by preventing the inhibition of GJIC.

3,6‐Anhydro‐l‐galactose (l‐AHG) is a bioactive sugar that is a major component of agarose. Recently, l‐AHG was reported to have anti‐melanogenic potential in human epidermal melanocytes (HEMs) and B16F10 melanoma cells; however, its underlying molecular mechanisms remain unknown. At noncytotoxic concentrations, l‐AHG has been shown to inhibit alpha‐melanocyte‐stimulating hormone‐induced melanin synthesis in various cell models, including HEMs, melan‐a cells, and B16F10 cells. Although l‐AHG did not inhibit tyrosinase activity in vitro, reverse transcription‐polymerase chain reaction results demonstrated that the anti‐melanogenic effect of l‐AHG was mediated by transcriptional repression of melanogenesis‐related genes, including tyrosinase, tyrosinase‐related protein‐1 (TRP‐1), tyrosinase‐related protein‐2 (TRP‐2), and microphthalmia‐associated transcription factor (MITF) in HEMs. Western blot analysis showed that l‐AHG effectively attenuated α‐melanocyte‐stimulating hormone‐induced melanogenic proteins by inhibiting cyclic adenosine monophosphate/cyclic adenosine monophosphate–dependent protein kinase, mitogen‐activated protein kinase, and Akt signaling pathways in HEMs. Topical application of l‐AHG significantly ameliorated melanin production in a 3D pigmented human skin model. Collectively, these results suggest that l‐AHG could be utilized as novel cosmetic compounds with skin‐whitening efficacy.

Various health effects have been attributed to the ginsenoside metabolite 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (GPD); however, its effect on ultraviolet (UV)-induced matrix metalloproteinase (MMP)-1 expression and the mechanism underlying this effect are unknown. We examined the inhibitory effect of GPD on UV-induced MMP-1 expression and its mechanisms in human dermal fibroblasts (HDFs). GPD attenuated UV-induced MMP-1 expression in HDFs and suppressed the UV-induced phosphorylation of mammalian target of rapamycin (mTOR) and p70(S6K) without inhibiting the activity of phosphatidylinositol 3-kinase and Akt, which are well-known upstream kinases of mTOR. GPD augmented the phosphorylation of liver kinase B1 (LKB1) and adenosine monophosphate-activated protein kinase (AMPK), which are inhibitors of mTOR, to a greater extent than UV treatment alone. Similar to GPD, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranosyl 5'-monophosphate (AICAR), an activator of AMPK, augmented UV-induced AMPK phosphorylation to a greater extent than UV treatment alone, resulting in the inhibition of MMP-1 expression. AICAR also decreased the phosphorylation of mTOR and p70(S6K). However, compound C, an antagonist of AMPK, increased MMP-1 expression. In HDF cells with AMPK knock-down using shRNA, MMP-1 expression was increased. These results indicate that AMPK activation plays a key role in MMP-1 suppression. Additionally, the cAMP-dependent protein kinase (PKA) inhibitor, H-89, antagonized GPD-mediated MMP-1 suppression via the inhibition of LKB1. Our results suggest that the suppressive activity of GPD on UV-induced MMP-1 expression is due to the activation of AMPK as a downstream of the PKA-LKB1 pathway.

Cyclooxygenase-2 (COX-2) is a major mediator of inflammation and increases carcinogenesis, and it has been reported to play a pivotal role in UVB-mediated skin carcinogenesis. Rutin (3-rhamnosyl-glucosyl quercetin) is found in numerous fruits and vegetables, especially buckwheat. Previous studies indicated that rutin has antioxidant, anti-inflammatory, and anti-carcinogenic activities both in vitro and in vivo. However, the molecular mechanisms underlying these effects of rutin remain unknown. Here, we identified that rutin suppressed UVB-induced COX-2 expression at both the protein and transcriptional levels in JB6 P+ mouse epidermal cells. The activation of nuclear factor (NF)-κB and activator protein-1 induced by UVB was dose dependently inhibited by rutin treatment. Western blot data revealed that rutin attenuated UVB-induced phosphorylation of ERK, MKK4, JNK, MKK3, and p38, but not MEK. Overall, these results indicated that rutin may be an effective anti-inflammatory agent in the skin.

Soybean-derived isoflavones have been investigated for their preventative effects against UV-induced symptoms of skin damage including wrinkle formation and inflammation. Haematococcus pluvialis is a freshwater species of Chlorophyta that contains high concentrations of the natural carotenoid pigment astaxanthin. Astaxanthin is known to be involved in retinoic acid receptor (RAR) signaling and previously been associated with the inhibition of activator protein (AP)-1 dependent transcription. Based on previous studies, we hypothesized that a combination of soy extract (SE) and Haematococcus extract (HE) may prevent UVB-induced photoaging through specific signaling pathways, as measured by UVB-induced wrinkling on hairless mice skin and expression changes in human dermal fibroblasts (HDFs). The 1: 2 ratio of SE and HE mixture (SHM) showed the optimal benefit in vivo. SHM was found to inhibit wrinkle formation via the downregulation of matrix metalloproteinase (MMP)-1 mRNA and protein expression. SHM also inhibited mitogen-activated protein kinase (MAPK) phosphorylation and the transactivation of AP-1 which plays an important role in regulating MMP expression. These results highlight the potential for SHM to be developed as a therapeutic agent to prevent UVB-induced skin wrinkling.

Cyanidin, an anthocyanidin found in fruits and vegetables, has been reported to possess anti-cancer effects. However, there is no study on the chemopreventive effect of cyanidin against neoplastic cell transformation and its molecular mechanisms. In the present study, we compare the anti-carcinogenic effects of cyanidin and cyanidin-3-glucoside (C3G) and investigate their underlying mechanisms. The inhibitory effect of cyanidin on EGF-induced cell transformation was higher than those of C3G in JB6 P+ mouse epidermal (JB6 P+) cells. Both cyanidin and C3G showed dose-dependent radical scavenging activities. It is indicated that the divergent inhibitory effects of cyanidin and C3G are not due to their antioxidant activities. We found that cyanidin, but not C3G, inhibited the EGF-induced Akt/p70S6K phosphorylation. Moreover, cyanidin directly suppressed the activity of PI3K by binding to PI3K directly in an ATP-competitive manner, which indicates that PI3K is one of the molecular targets of cyanidin.

3,6-Anhydro-l-galactose (L-AHG) constitutes 50 % of agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, agarose was converted to L-AHG in the following three steps: pre-hydrolysis of agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

Myricetin is a widely distributed flavonol that is found in many plants, including tea, berries, fruits, vegetables, and medicinal herbs. Abundant sources provide interesting insights into the multiple mechanisms by which myricetin mediates chemopreventive effects on skin cancer. Myricetin strongly inhibited tumor promoter-induced neoplastic cell transformation by inhibiting MEK, JAK1, Akt, and MKK4 kinase activity directly. In a mouse skin model, myricetin attenuated the ultraviolet B (UVB)-induced COX-2 expression and skin tumor formation by regulating Fyn. Myricetin-mediated inactivation of Akt in the UVB response plays a role in regulating UVB-induced carcinogenesis. Recently, myricetin was found to inhibit UVB-induced angiogenesis by targeting PI3-K in an SKH-1 hairless mouse skin tumorigenesis model. Raf kinase is a critical target for myricetin in inhibiting the UVB-induced formation of wrinkles and suppression of type I procollagen and collagen levels in mouse skin. Accumulated data suggest that myricetin acts as a promising agent for the chemoprevention of skin cancer.

Multiple lines of evidences suggest that oxidative stress induced by reactive oxygen species are closely related to multi-stage carcinogenesis. Polyphenols, a group of chemicals with more than one phenol unit or building block per molecule, have been recognized for possessing many health benefits including cancer-preventive effects mainly due to their antioxidant activity. However, polyphenols can directly bind with signaling molecules involved in carcinogenesis and regulate its activity. Moreover, it is noteworthy that the binding between the polyphenol and the target protein is determined by their structural relationship, which implies that different polyphenols have different target proteins, leading to divergent chemopreventive effects. Extracellular stimuli transmit signals into a cell by activating their target signaling cascades involved in carcinogenesis. As an example, Src family kinase, a family of proto-oncogenic tyrosine kinases activated by a variety of oxidative stress and proinflammatory agents, is known to regulate cell proliferation, differentiation, survival and angiogenesis. Src family kinase subsequently activates downstream signal cascades including mitogen-activated protein kinase, phosphoinositol-3-kinase, and nuclear factor-kappaB, thereby inducing cell proliferation and causing cancer. Recent studies demonstrate that polyphenols can directly target signaling cascades involved in inflammation and the development of cancer. Inhibition of the kinases by polyphenols contributes to the attenuation of carcinogenesis. Therefore, the development of polyphenols as direct inhibitors against target proteins is regarded as a rational approach for chemoprevention. This review describes and discusses recent results about the direct interactions of polyphenols and protein kinases in cancer chemoprevention.

Nonmelanoma skin cancer is one of the most frequently occurring cancers in the United States. Chronic exposure to UVB irradiation is a major cause of this cancer. Daidzein, along with genistein, is a major isoflavone found in soybeans; however, little is known about the chemopreventive effects of daidzein and its metabolites in UVB-induced skin cancer. Here, we found that 7,3′,4′-trihydroxyisoflavone (THIF), a major metabolite of daidzein, effectively inhibits UVB-induced cyclooxygenase 2 (COX-2) expression through the inhibition of NF-κB transcription activity in mouse skin epidermal JB6 P+ cells. In contrast, daidzein had no effect on COX-2 expression levels. Data from Western blot and kinase assays showed that 7,3′,4′-THIF inhibited Cot and MKK4 activity, thereby suppressing UVB-induced phosphorylation of mitogen-activated protein kinases. Pull-down assays indicated that 7,3′,4′-THIF competed with ATP to inhibit Cot or MKK4 activity. Topical application of 7,3′,4′-THIF clearly suppressed the incidence and multiplicity of UVB-induced tumors in hairless mouse skin. Hairless mouse skin results also showed that 7,3′,4′-THIF inhibits Cot or MKK4 kinase activity directly, resulting in suppressed UVB-induced COX-2 expression. A docking study revealed that 7,3′,4′-THIF, but not daidzein, easily docked to the ATP binding site of Cot and MKK4, which is located between the N- and C-lobes of the kinase domain. Collectively, these results provide insight into the biological actions of 7,3′,4′-THIF, a potential skin cancer chemopreventive agent.

Numerous in vitro and in vivo studies have shown that isoflavones exhibit anti-proliferative activity against epidermal growth factor (EGF) receptor-positive malignancies of the breast, colon, skin, and prostate. 7,3',4'-Trihydroxyisoflavone (7,3',4'-THIF) is one of the metabolites of daidzein, a well known soy isoflavone, but its chemopreventive activity and the underlying molecular mechanisms are poorly understood. In this study, 7,3',4'-THIF prevented EGF-induced neoplastic transformation and proliferation of JB6 P+ mouse epidermal cells. It significantly blocked cell cycle progression of EGF-stimulated cells at the G(1) phase. As shown by Western blot, 7,3',4'-THIF suppressed the phosphorylation of retinoblastoma protein at Ser-795 and Ser-807/Ser-811, which are the specific sites of phosphorylation by cyclin-dependent kinase (CDK) 4. It also inhibited the expression of G(1) phase-regulatory proteins, including cyclin D1, CDK4, cyclin E, and CDK2. In addition to regulating the expression of cell cycle-regulatory proteins, 7,3',4'-THIF bound to CDK4 and CDK2 and strongly inhibited their kinase activities. It also bound to phosphatidylinositol 3-kinase (PI3K), strongly inhibiting its kinase activity and thereby suppressing the Akt/GSK-3beta/AP-1 pathway and subsequently attenuating the expression of cyclin D1. Collectively, these results suggest that CDKs and PI3K are the primary molecular targets of 7,3',4'-THIF in the suppression of EGF-induced cell proliferation. These insights into the biological actions of 7,3',4'-THIF provide a molecular basis for the possible development of new chemoprotective agents.

Chronic exposure to solar ultraviolet (UV) light causes skin photoaging. Many studies have shown that naturally occurring phytochemicals have anti-photoaging effects, but their direct target molecule(s) and mechanism(s) remain unclear. We found that myricetin, a major flavonoid in berries and red wine, inhibited wrinkle formation in mouse skin induced by chronic UVB irradiation (0.18J/cm(2), 3 days/week for 15 weeks). Myricetin treatment reduced UVB-induced epidermal thickening of mouse skin and also suppressed UVB-induced matrix metalloproteinase-9 (MMP-9) protein expression and enzyme activity. Myricetin appeared to exert its anti-aging effects by suppressing UVB-induced Raf kinase activity and subsequent attenuation of UVB-induced phosphorylation of MEK and ERK in mouse skin. In vitro and in vivo pull-down assays revealed that myricetin bound with Raf in an ATP-noncompetitive manner. Overall, these results indicate that myricetin exerts potent anti-photoaging activity by regulating MMP-9 expression through the suppression of Raf kinase activity.

Oxidative stress induced by reactive oxygen species (ROS) is strongly associated with the pathogenesis of various neurodegenerative disorders, including Alzheimer's disease. We investigated the possible combined effects of gallic acid and resveratrol, which are major antioxidants present in fruit, including grapes, on PC12 rat pheochromocytoma (PC12) cell death. Gallic acid did not protect against H(2)O(2)-induced PC12 cell death; it reduced the viability of PC12 cells in a dose-dependent manner. Gallic acid also induced cleavage of poly (ADP-ribose) polymerase, which is strongly related to apoptosis in neurons. Gallic acid induced the phosphorylation of c-Jun N-terminal protein kinase (JNK) and the downregulation of Bcl-2 in PC12 cells. Treatment of PC12 cells with resveratrol increased their viability in a dose-dependent manner by blocking the activation of JNK and the downregulation of Bcl-2. Furthermore, gallic acid led to a progressive reduction in the viability of vector-transfected PC12 cells, which was delayed in PC12 cells that overexpressed Bcl-2. The JNK inhibitor SP600125 protected against gallic acid-induced PC12 cell death. Collectively, these findings suggest that the combined effects of dietary phenolic phytochemicals on oxidative neuronal cell death and antioxidants differ in ROS-mediated neuronal cell death.

Tumor necrosis factor (TNF)-alpha-mediated cyclooxygenase (COX)-2 expression plays key roles in inflammation and tumorigenesis, particularly skin carcinogenesis, and hence targeting the TNF-alpha-mediated signaling pathway might be a promising strategy for developing chemopreventive agents against skin cancer and other skin disorders. Here we report that Fyn kinase - one of the members of the nonreceptor protein tyrosine kinase family - is involved in TNF-alpha-induced COX-2 expression, and that delphinidin - a major anthocyanidin present in red wine and berries - inhibits these effects by directly inhibiting Fyn kinase activity. Delphinidin strongly inhibited TNF-alpha-induced COX-2 expression in JB6 P+ mouse epidermal (JB6 P+) cells, whereas two other major phenolic compounds (resveratrol and gallic acid) did not exert significant inhibitory effects. Delphinidin inhibited the TNF-alpha-induced phosphorylations of JNK, p38 MAP kinase, Akt, p90RSK, MSK1, and ERK, and subsequently blocked the activation of the eukaryotic transcription factors AP-1 and NF-kappaB. Kinase and pull-down assay data revealed that delphinidin inhibited Fyn kinase activity and directly bound with Fyn kinase noncompetitively with ATP. By using PP2 (a commercial inhibitor of Fyn kinase) and siRNA-Fyn, we confirmed that Fyn kinase is involved in TNF-alpha-induced COX-2 expression mainly by down-regulating JNK in JB6 P+ cells. Together these findings suggest that the targeted inhibition of Fyn kinase activity and COX-2 expression by delphinidin contributes to the chemopreventive potential of red wine and berries.

Neurodegenerative disorders such as Alzheimer's disease (AD) are strongly associated with oxidative stress, which is induced by reactive oxygen species (ROS) including hydrogen peroxide (H(2)O(2)). Recent studies suggest that moderate coffee consumption may reduce the risk of neurodegenerative diseases such as AD, but the molecular mechanisms underlying this effect remain to be clarified. In this study, we investigated the protective effects of chlorogenic acid (5-O-caffeoylquinic acid; CGA), a major phenolic phytochemical found in instant decaffeinated coffee (IDC), and IDC against oxidative PC12 neuronal cell death. IDC (1 and 5 microg/ml) or CGA (1 and 5 microM) attenuated H(2)O(2)-induced PC12 cell death. H(2)O(2)-induced nuclear condensation and DNA fragmentation were strongly inhibited by pretreatment with IDC or CGA. Pretreatment with IDC or CGA also inhibited the H(2)O(2)-induced cleavage of poly(ADP-ribose) polymerase (PARP), and downregulation of Bcl-X(L) and caspase-3. The accumulation of intracellular ROS in H(2)O(2)-treated PC12 cells was dose-dependently diminished by IDC or CGA. The activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) by H(2)O(2) in PC12 cells was also inhibited by IDC or CGA. Collectively, these results indicate that IDC and CGA protect PC12 cells from H(2)O(2)-induced apoptosis by blocking the accumulation of intracellular ROS and the activation of MAPKs.

Recent studies suggest that anthocyanidins play a pivotal role in the chemopreventive effects of fruits and vegetables. However, the underlying molecular mechanisms and cellular targets remain unknown. Neoplastic transformation of cells and inflammation are considered to be major events contributing to carcinogenesis. Here, we report that delphinidin, a major dietary anthocyanidin, inhibits tumor promoter–induced transformation and cyclooxygenase-2 (COX-2) expression in JB6 promotion-sensitive mouse skin epidermal (JB6 P+) cells by directly targeting Raf and mitogen-activated protein kinase kinase (MEK). Delphinidin inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)–induced neoplastic transformation and COX-2 expression at both the protein and transcriptional levels. The activation of activator protein-1 and nuclear factor-κB induced by TPA was dose dependently inhibited by delphinidin treatment. Delphinidin strongly suppressed Raf1 and MEK1 kinase activities and subsequently attenuated TPA-induced phosphorylation of MEK, extracellular signal-regulated kinase (ERK), p90RSK, and MSK. Although delphinidin suppressed ERK and c-Jun NH2-terminal kinase activities, it was more effective at inhibiting Raf1 or MEK1 activities. Pull-down and competition assays revealed that delphinidin binds with Raf1 or MEK1 noncompetitively with ATP. Delphinidin also dose dependently suppressed JB6 P+ cell transformation induced by epidermal growth factor and H-Ras, both of which are involved in the activation of Raf/MEK/ERK signaling. Together, these findings suggested that the targeted inhibition of Raf1 and MEK activities and COX-2 expression by delphinidin contribute to the chemopreventive potential of fruits and vegetables.

Cocoa was shown to inhibit chemically induced carcinogenesis in animals and exert antioxidant activity in humans. However, the molecular mechanisms of the chemopreventive potential of cocoa and its active ingredient(s) remain unknown. Here we report that cocoa procyanidins inhibit neoplastic cell transformation by suppressing the kinase activity of mitogen-activated protein kinase kinase (MEK). A cocoa procyanidin fraction (CPF) and procyanidin B2 at 5 μg/ml and 40 μm, respectively, inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation of JB6 P+ mouse epidermal (JB6 P+) cells by 47 and 93%, respectively. The TPA-induced promoter activity and expression of cyclooxygenase-2, which is involved in tumor promotion and inflammation, were dose-dependently inhibited by CPF or procyanidin B2. The activation of activator protein-1 and nuclear factor-κB induced by TPA was also attenuated by CPF or procyanidin B2. The TPA-induced phosphorylation of MEK, extracellular signal-regulated kinase, and p90 ribosomal s6 kinase was suppressed by CPF or procyanidin B2. In vitro and ex vivo kinase assay data demonstrated that CPF or procyanidin B2 inhibited the kinase activity of MEK1 and directly bound with MEK1. CPF or procyanidin B2 suppressed JB6 P+ cell transformation induced by epidermal growth factor or H-Ras, both of which are known to be involved in MEK/ERK signal activation. In contrast, theobromine (up to 80 μm) had no effect on TPA-induced transformation, cyclooxygenase-2 expression, the transactivation of activator protein-1 or nuclear factor-κB, or MEK. Notably, procyanidin B2 exerted stronger inhibitory effects compared with PD098059 (a well known pharmacological inhibitor of MEK) on MEK1 activity and neoplastic cell transformation.

Some xanthine analogues, including 1,3,7-trimethylxanthine (caffeine) and 1,3-dimethylxanthine (theophylline), have been shown to exert anticancer activities in both cell culture and animal models. The present study focused on the relationship of structure and activity of 50 different caffeine analogues in preventing epidermal growth factor (EGF)-induced malignant transformation of mouse epidermal JB6 promotion-sensitive (P+) Cl41 (JB6 P+) cells. Results indicated that the inhibition of cell transformation by the 1,3,7-trialkylxanthines depends on the number of carbons at the alkyl groups R1 and R3, but not R7. Notably, 1-ethyl-3-hexylxanthine (xanthine 70) was the most effective compound for inhibiting EGF-induced neoplastic transformation among the 50 xanthine analogues tested. The 50% inhibition of cell transformation (ICT(50)) value for xanthine 70 was 48- or 75-fold less than the ICT(50) value of caffeine or theophylline, respectively. Further study revealed that xanthine 70 (5-40 muM) dose dependently inhibited EGF-induced transactivation of activator protein 1 (AP-1), whereas theophylline or caffeine (up to 500 muM) had no effect on AP-1 activity. In addition, xanthine 70 (10 muM) inhibited 12-O-tetradecanoylphorbol-13-acetate- or H-Ras-induced neoplastic transformation in JB6 P+ cells by 78.2 or 62.0%, respectively. Collectively, these results indicated that the number of carbons at R1 and R3 is important for the antitumor-promoting activity of the trialkylxanthines and xanthine 70 might be a promising anticancer agent.

Mitogen- and stress-activated kinase 1 (MSK1) belongs to a family of dual protein kinases that are activated by either extracellular signal-regulated kinase or p38 mitogen-activated protein kinases in response to stress or mitogenic extracellular stimuli. The physiologic role of MSK1 in malignant transformation and cancer development is not well understood. Here, we report that MSK1 is involved in 12-O-tetradecanoylphorbol-13-acetate (TPA)–induced or epidermal growth factor (EGF)–induced neoplastic transformation of JB6 Cl41 cells. H89, a potent inhibitor of MSK1, strongly suppressed TPA-induced or EGF-induced cell transformation. When cells overexpressing wild-type MSK1 were treated with TPA or EGF, colony formation increased substantially compared with untreated cells or cells that did not overexpress MSK1. In contrast, MSK1 COOH terminal or NH2 terminal dead dominant negative mutants dramatically suppressed cell transformation. Introduction of small interfering RNA-MSK1 into JB6 Cl41 cells resulted in suppressed TPA-induced or EGF-induced cell transformation. In addition, cell proliferation was inhibited in MSK1 knockdown cells compared with MSK1 wild-type cells. In wild-type MSK1-overexpressing cells, activator protein (AP-1) activation increased after TPA or EGF stimulation, whereas AP-1 activation decreased in both MSK1 dominant-negative mutants and in MSK1 knockdown cells. Moreover, TPA-induced or EGF-induced phosphorylation of histone H3 at Ser10 was increased in wild-type cells but the induced phosphorylation was abolished in MSK1 dominant-negative mutant or MSK1 knockdown cells. Thus, MSK1 is required for tumor promoter-induced cell transformation through its phosphorylation of histone H3 at Ser10 and AP-1 activation. [Cancer Res 2008;68(7):2538–47]

Propyl gallate and its metabolite, gallic acid, are widely used as antioxidants in the food industry, but they have been shown to exhibit liver toxicity and enhance carcinogenesis. In the present study, we investigated the possible undesirable effects of propyl gallate and gallic acid on gap junctional intercellular communication (GJIC), inhibition of which is closely linked to carcinogenesis. Gallic acid and propyl gallate exhibited dose-dependent free-radical-scavenging activities as determined by 1,1-diphenyl-2-picrylhydrazyl- or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical-scavenging assays, and the free-radical-scavenging activity of gallic acid was stronger than that of propyl gallate. However, using WB-F344 rat liver epithelial cells, gallic acid inhibited GJIC in a dose-dependent manner, while propyl gallate had no significant effect compared with untreated controls. The gallic-acid-induced inhibition of GJIC was reversible, with a recovery of nearly 65% after 120 min. Gallic acid induced the phosphorylation of connexin 43 (Cx43) and phosphorylation of extracellular-signal-regulated kinase1/2 (ERK1/2). The gallic-acid-induced inhibition of GJIC was attenuated by treatment with mitogen-activated protein kinase kinase inhibitors (U0126 and PD098059). U0126 blocked the gallic-acid-induced phosphorylation of Cx43 and ERK1/2, indicating that the gallic-acid-induced inhibition of GJIC is mediated by phosphorylation of Cx43 via activation of ERK1/2. In addition, gallic-acid-induced inhibition of GJIC was protected by ascorbic acid and quercetin, which might represent a simple example of the different effects of natural antioxidants in carcinogenesis.

Numerous studies have shown that the levels of matrix metalloproteinase (MMP)-2 and/or MMP-9 are associated with the invasive phenotypes of cancer cells. This study investigated the effects of caffeic acid phenethyl ester (CAPE), a chemopreventive phytochemical derived from honeybee propolis, on the invasive phenotype of SK-Hep1 human hepatocellular carcinoma cells (SK-Hep1 cells). CAPE effectively suppressed SK-Hep1 cell invasion in a dose-dependent manner. The constitutive expression of MMP-2 and MMP-9 in SK-Hep1 cells was almost completely abolished by treatment with 12.5 muM CAPE. CAPE also significantly inhibited nuclear factor kappa B (NF-kappaB) DNA-binding activity in SK-Hep1 cells. These results taken together suggest that CAPE exerts antimetastatic potential through inhibition of MMP-2 and MMP-9 expression, possibly by targeting NF-kappaB in hepatocellular carcinoma.

Daidzein and genistein are isoflavones found in soybean. Genistein is known to exhibit anticarcinogenic activities and inhibit tyrosine kinase activity. However, the underlying molecular mechanisms of the chemopreventive activities of daidzein and its metabolite, equol, are not understood. Here we report that equol inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation of JB6 P+ mouse epidermal cells by targeting the MEK/ERK/p90RSK/activator protein-1 signaling pathway. TPA-induced neoplastic cell transformation was inhibited by equol, but not daidzein, at noncytotoxic concentrations in a dose-dependent manner. Equol dose-dependently attenuated TPA-induced activation of activator protein-1 and c-fos, whereas daidzein did not exert any effect when tested at the same concentrations. The TPA-induced phosphorylation of ERK1/2, p90RSK, and Elk, but not MEK or c-Jun N-terminal kinase, was inhibited by equol but not by daidzein. In vitro kinase assays revealed that equol greatly inhibited MEK1, but not Raf1, kinase activity, and an ex vivo kinase assay also demonstrated that equol suppressed TPA-induced MEK1 kinase activity in JB6 P+ cell lysates. Equol dose-dependently inhibited neoplastic transformation of JB6 P+ cells induced by epidermal growth factor or H-Ras. Both in vitro and ex vivo pull-down assays revealed that equol directly bound with glutathione S-transferase-MEK1 to inhibit MEK1 activity without competing with ATP. These results suggested that the antitumor-promoting effect of equol is due to the inhibition of cell transformation mainly by targeting a MEK signaling pathway. These findings are the first to reveal a molecular basis for the anticancer action of equol and may partially account for the reported chemopreventive effects of soybean.

Evidence suggests that mitogen-activated protein kinase kinase (MEK) plays a role in cell transformation and tumor development and might be a significant target for chemoprevention. 3,5,4'-Trihydroxy-trans-stilbene (resveratrol), a non-flavonoid polyphenol found in various foods and beverages, including red wines, is reported to be a natural chemopreventive agent. However, the concentrations required to exert these effects might be difficult to achieve by drinking only one or two glasses of red wine a day. On the other hand, the flavonol content of red wine is approximately 30 times higher than that of resveratrol. Here we demonstrated that 3,3',4',5,5',7-hexahydroxyflavone (myricetin), one of the major flavonols in red wine, is a novel inhibitor of MEK1 activity and transformation of JB6 P+ mouse epidermal cells. Myricetin (10 microM) inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA) or epidermal growth factor (EGF)-induced cell transformation by 76 or 72%, respectively, compared with respective reductions of 26 or 19% by resveratrol (20 microM). A combination of myricetin and resveratrol exerted additive but not synergistic effects on either TPA- or EGF-induced transformation. Myricetin, but not resveratrol, attenuated tumor promoter-induced activation of c-fos or activator protein-1. Myricetin strongly inhibited MEK1 kinase activity and suppressed TPA- or EGF-induced phosphorylation of extracellular signal-regulated kinase (ERK) or p90 ribosomal S6 kinase, downstream targets of MEK. Moreover, myricetin inhibited H-Ras-induced cell transformation more effectively than either PD098059, a MEK inhibitor, or resveratrol. Myricetin directly bound with glutathione S-transferase-MEK1 but did not compete with ATP. Overall, these results indicated that myricetin has potent anticancer-promoting activity and mainly targets MEK signaling, which may contribute to the chemopreventive potential of several foods including red wines.

One of the most frequent events in carcinogenesis is uncontrolled activation of Ras signaling pathway. A previous study demonstrated that the introduction of H-Ras into the normal WB-F344 rat liver epithelial (WB) cell line and adult male F344 rats resulted in tumorigenicity. The present study investigated whether H-Ras induced the invasive and migrative phenotypes in WB cells, and subsequently aimed at characterizing the underlying mechanisms. H-Ras induced the invasive and migrative phenotypes of WB cells with a selective up-regulation of matrix metalloproteinase (MMP)-9, but not MMP-2. Cyclooxygenase (COX)-2 and the subsequent production of prostaglandin E2 (PGE2) were also induced by H-Ras. Treatment of H-Ras WB cells with GM6001 and NS398, the inhibitors of MMPs and COX-2, respectively, significantly inhibited the H-Ras-induced invasive and migrative phenotypes. DNA binding activity of nuclear factor (NF)-kappaB, but not that of activator protein (AP)-1, was increased by H-Ras. Caffeic acid phenethyl ester and Bay 11-7082, specific inhibitors of NF-kappaB and IKK, respectively, significantly inhibited the expression of MMP-9 and COX-2, invasion and migration of H-Ras WB cells, revealing NF-kappaB as a transcriptional factor responsible for H-Ras-induced malignant phenotypic conversion of WB cells. Activation of ERKs pathway was critical for H-Ras-induced invasive and migrative phenotypes, up-regulation of MMP-9 and COX-2 as well as enhanced DNA binding activity of NF-kappaB in WB cells. Taken together, these results demonstrate that H-Ras up-regulates MMP-9 and COX-2 through activation of ERKs and IKK-IkappaBalpha-NF-kappaB signal pathway which may contribute to the malignant progression of WB rat liver epithelial cells.

The utilization of cacao bean husk (CBH), a by-product of chocolate manufacture, would be both environmentally and economically beneficial. For this purpose, a process for effectively separating and fractionating CBH fractions having cancer preventive potential was developed in this study. For screening the fractions with potent cancer preventive activity, we examined the effect of extracts and fractions of CBH on the inhibition of gap-junction intercellular communication (GJIC) and the DNA synthesis of cancer cells, both of which are characteristics of the promotion and progression stages in carcinogenesis. The extracts of CBH (especially, the 60% ethanol fraction after extraction with 50% acetone) containing 43 wt.% polyphenol exerted an excellent protective effect on H 2 O 2 -induced inhibition of GJIC in WB-F344 rat liver epithelial cells as determined by the scrape-loading/dye transfer assay. The enhancement of GJIC by the extracts of CBH was approximately 10-fold higher than that of a well-known dietary chemopreventive component, vitamin C. The extracts of CBH (especially, the 60% ethanol fraction) also suppressed DNA synthesis in all liver, stomach, and colon cancer cells as demonstrated by the 3 H-thymidine incorporation assay, by approximately four-fold higher than that of vitamin C. These results imply that the polyphenol extracts and fractions of CBH are effective functional materials to be used in either preventing or inhibiting cancer.

Ginsenoside F1 (GF1) is a metabolite produced by hydrolysis of the ginsenoside Re and Rg1 in Panax ginseng. According to various studies, high amounts of ginseng components are absorbed in the metabolized form, which are key constituents responsible for the biological effects of P. ginseng. Recently, GF1 was reported to have beneficial effects on skin. However, there has not been a sound understanding of its antimelanogenic effect and underlying molecular mechanisms. In this study, GF1 reduced α-melanocyte-stimulating hormone-induced melanin secretion in B16F10 cell culture media by 60%. However, it did not suppress intracellular melanin levels, tyrosinase activity and expression. Immunofluorescence assay showed that GF1 had no effect on melanosome transport, but significantly induced dendrite retraction. Pull-down assay demonstrated that GF1 primarily modulates the Rho family GTPases resulting in dendrite retraction. Collectively, these data suggest that GF1 could act as a potent skin-whitening agent.