Characterization and applications of biomacromolecule structurally similar to glycogen as a dispersion aid and skin protection agent

Glycogen is a naturally occurring or metabolically synthesized biological macromolecule found in a wide range of living organisms, including animals, microorganisms, and even plants. However, naturally sourced glycogen poses challenges for industrial use. This study focused on a biological macromolecule referred to as glycogen-like particles (GLPs), detailing the production methods and biological properties of these particles. In vitro enzymatic production of GLPs was successfully achieved. GLPs synthesized through a simultaneous enzymatic reaction using sucrose had significant changes in their structure and functionality based on the branching enzyme (BE) to amylosucrase (ASase) ratio. As this ratio increased, the GLPs developed higher molecular weights and greater density, solubility, and branching degree while reducing size and turbidity. Structural changes in these enzymes were not observed beyond a critical BE/ASase ratio. Uniformly dispersed curcumin powder was generated in 50 % (w/v) aqueous GLP solution, and the GLPs were non-toxic to human skin keratinocytes at a concentration of 2.5 mg/mL. GLPs with lower branching inhibited tyrosinase activity and melanin synthesis, while those with more long chains displayed effective UV-blocking. By manipulating the BE/ASase ratio, GLPs were shown to display diverse chemical structures and physical characteristics, suggesting their potential application in the food and cosmetics industries.

Inhibition of Photoaging by Anthocyanin Metabolites Derived from Rose Petal Extract

SCOPE

Rose petal extract (RPE) shows a significant antioxidant effect through its anthocyanin content. However, the mechanism underlying the anti-aging effects of orally administered RPE remains unclear. This study aims to describe the anti-aging effect and mechanism of action of orally administered RPE in ultraviolet (UV)B-induced skin aging.

METHODS AND RESULTS

This study evaluates the protein expression of collagen type I alpha 1 (COL1A1) and matrix metalloproteinase 1 (MMP-1) and the mRNA expression of hyaluronic synthase 2 (HAS2) in human dermal fibroblasts. In addition, the hyaluronidase and collagenase inhibitory activities of RPE are confirmed. To evaluate the anti-aging effects of RPE, SKH-1 hairless mice are administered RPE daily for 12 weeks. Wrinkle formation, transepidermal water loss (TEWL), and skin moisture loss induced by UVB irradiation are suppressed in the dorsal skin of SKH-1 hairless mice orally administered RPE. Oral administration of RPE suppresses UVB irradiation-induced collagen disruption and reduction of hyaluronic acid. To find the bioactive compound in the RPE, serum protocatechuic acid (PCA), an anthocyanin metabolite, is analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

CONCLUSION

Anthocyanins in RPE are metabolized to PCA in the body and circulated through the bloodstream to exhibit anti-aging effects on the skin.

Skin-whitening effects of Spergularia marina by suppressing MITF translocation

Spergularia marina is a plant that grows in salty regions along the coastline and exerts radical-scavenging and anti-inflammatory effects. In this study, we investigated the skin-whitening effects of S. marina extract (SME) in B16F10 melanoma cells. SME was found to exert radical-scavenging effects. It suppressed α-melanocyte-stimulating hormone-induced melanogenesis and tyrosinase activity. We also assessed the melanin production signaling pathway to identify the inhibitory action mechanism of SME on melanogenesis. SME decreased the protein expression levels of tyrosinase-related protein (TRP)-1, TRP-2, and tyrosinase, which play important roles in melanogenesis. Furthermore, western blotting revealed that SME inhibited the nuclear translocation of melanocyte inducing transcription factor (MITF), which is a transcription factor for TRP-1, TRP-2, and tyrosinase, suggesting that SME exerts its skin-whitening effect by inhibiting MITF nuclear translocation. Therefore, SME may potentially be used in skin-whitening medicines and cosmetics.

Oral administration of collagen peptide in SKH-1 mice suppress UVB-induced wrinkle and dehydration through MAPK and MAPKK signaling pathways, in vitro and in vivo evidence

Skin aging is induced by exposure to extrinsic factors, causing various diseases and adversely affecting aesthetics. Studies have suggested that as the quality of life improves, demand for beauty and nutritional cosmetics increases. Here, the protective effects of collagen peptide against UV-induced skin damage were evaluated in vitro and in vivo. Collagen peptide inhibited water loss and UVB irradiation-induced HA degradation in the skin of SKH-1 mice. Additionally, collagen peptide dose-dependently inhibited UVB-induced wrinkle formation, epidermal thickness, and elastase activity. These results suggest that collagen peptide regulates collagen degradation through the MAPK and MAPKK pathway. In addition, collagen peptide administration did not affect changes in weight of the liver, spleen, and kidney, or enzymatic indicators of liver damage. Taken together, oral administration of collagen peptide improved the effects of UV-induced skin aging without toxicity. Therefore, this study supports the development of collagen peptide for skin aging prevention in nutricosmetic products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01362-6.

Porcine Placenta Peptide Inhibits UVB-Induced Skin Wrinkle Formation and Dehydration: Insights into MAPK Signaling Pathways from In Vitro and In Vivo Studies

Excessive exposure to ultraviolet (UV) radiation from sunlight accelerates skin aging, leading to various clinical manifestations such as wrinkles, dryness, and loss of elasticity. This study investigated the protective effects of porcine placenta peptide (PPP) against UVB-induced skin photoaging. Female hairless SKH-1 mice were orally administered PPP for 12 weeks, followed by UVB irradiation. PPP significantly reduced wrinkle formation, improved skin moisture levels, and prevented collagen degradation. Mechanistically, PPP inhibited the expression of matrix metalloproteinases (MMPs) and upregulated collagen production. Moreover, PPP elevated hyaluronic acid levels, contributing to enhanced skin hydration. Additionally, PPP demonstrated antioxidant properties by increasing the expression of the antioxidant enzyme GPx-1, thereby reducing UVB-induced inflammation. Further molecular analysis revealed that PPP suppressed the activation of p38 MAP kinase and JNK signaling pathways, crucial mediators of UV-induced skin damage. These findings highlight the potential of porcine placental peptides as a natural and effective intervention against UVB-induced skin photoaging. The study provides valuable insights into the mechanisms underlying the protective effects of PPP, emphasizing its potential applications in skincare and anti-aging formulations.

Water Extract of Capsella bursa-pastoris Mitigates Doxorubicin-Induced Cardiotoxicity by Upregulating Antioxidant Enzymes

Doxorubicin (DOX), an effective chemotherapeutic drug, causes cardiotoxicity in a cumulative and dose-dependent manner. The aim of this study is to investigate the effects of hot-water extract of Capsella bursa-pastoris (CBW) on DOX-induced cardiotoxicity (DICT). We utilized H9c2 rat cardiomyocytes and MDA-MB-231 human breast cancer cells to evaluate the effects of CBW on DOX-induced cell death. Superoxide dismutase (SOD) levels, reactive oxygen species (ROS) production, and oxygen consumption rate were measured in H9c2 cells. C57BL/6 mice were treated with DOX and CBW to assess their impact on various cardiac parameters. Human-induced pluripotent stem-cell-derived cardiomyocytes were also used to investigate DOX-induced electrophysiological changes and the potential ameliorative effects of CBW. UPLC-TQ/MS analysis identified seven flavonoids in CBW, with luteolin-7-O-glucoside and isoorientin as the major compounds. CBW inhibited DOX-induced death of H9c2 rat cardiomyocytes but did not affect DOX-induced death of MDA-MB-231 human breast cancer cells. CBW increased SOD levels in a dose-dependent manner, reducing ROS production and increasing the oxygen consumption rate in H9c2 cells. The heart rate, RR interval, QT, and ST prolongation remarkably recovered in C57BL/6 mice treated with the combination of DOX and CBW compared to those in mice treated with DOX alone. Administration of CBW with DOX effectively alleviated collagen accumulation, cell death in mouse heart tissues, and reduced the levels of creatinine kinase (CK) and lactate dehydrogenase (LDH) in serum. Furthermore, DOX-induced pathological electrophysiological features in human-induced pluripotent stem-cell-derived cardiomyocytes were ameliorated by CBW. CBW may prevent DICT by stabilizing SOD and scavenging ROS. The presence of flavonoids, particularly luteolin-7-O-glucoside and isoorientin, in CBW may contribute to its protective effects. These results suggest the potential of CBW as a traditional therapeutic option to mitigate DOX-induced cardiotoxicity.

Rosa gallica and its active compound, cyanidin-3,5-O-diglucoside, improve skin hydration via the GLK signaling pathway

Rosa gallica has been previously reported to display anti-inflammatory, anti-oxidative, and anti-skin wrinkle activities. However, the effect of Rosa gallica on skin hydration and its active components are largely unknown. Herein, we aimed to investigate the skin hydration effect of rose petal extract (RPE) in humans and elucidate the underlying molecular mechanism. A double-blinded clinical study was performed to investigate the effect of RPE on skin hydration. Stratum corneum moisture analysis demonstrated that RPE treatment significantly improved hydration levels in human skin. Furthermore, HAS2 and hyaluronic acid levels were notably increased by RPE in keratinocytes and 3D human skin equivalent model. By comparing the modulatory effect on HAS2 expression, cyanidin-3,5-O-diglucoside (CDG) was identified as the most potent compound in RPE likely responsible for skin hydration. The kinase activity of GLK, an upstream regulator of MAPK signaling, was increased by CDG in a dose-dependent manner. Importantly, silencing GLK reversed CDG-mediated HAS2 upregulation, further supporting the involvement of GLK in the CDG-mediated effects. Binding of CDG to GLK was confirmed by pull-down assay and computer modeling. These findings suggest that RPE and its active component CDG increases skin hydration by upregulating HAS2 expression through modulating the GLK-MAP2K-MAPK signaling pathway.

Blue honeysuckle rich in cyanidin-3-O-glucoside inhibited adipogenic differentiation by modulation of the adipogenesis pathway in 3T3-L1 adipocytes

Background: Blue honeysuckle (BH; Lonicera caerulea L.), which is a traditional medicinal plant, is known to be a rich source of anthocyanins and phenolic acids due to its strong antioxidant and anti-inflammatory activities. Its anti-obesity effects, which are a result of attenuating abnormal lipid and glucose metabolisms, have also been reported. Aim: The purpose of this study is to investigate the effect of BH on genes and proteins that are involved in the adipocyte differentiation using 3T3-L1 cells. Methods: The effects of the water extracts of the BH were examined on adipogenesis and lipolysis using a biochemical and molecular analysis of the 3T3-L1 cells. Results: Cyanidin-3-O-glucoside (C3G) from the BH extract was determined in order to contain 1.67 mg/g by the high-performance liquid chromatography analysis. The lipid accumulation in the adipocytes was reduced, which ranged from 58 to 26% in the BH (500 and 1,000 µg/mL) compared to the control group. The lipolysis that was measured by the glycerol content was not affected by the BH at 1,000 μg/mL. The BH downregulated the expression of the main transcription factors of the adipogenesis pathway, such as peroxisome proliferator-activated receptor γ, 1, 2, adipose differentiation-related protein, CCAAT/enhancer binding protein α, and acetyl CoA carboxylase, while increasing the expression of the Adenosine monophosphate (AMP)-activated protein kinase α. Conclusion: These findings suggest that the BH is a good source of C3G, and it could be effective in regard to inhibiting the adipogenesis as opposed to the lipolysis, which indicates the potential for natural anti-obesity ingredients.

Umbilicaria esculenta Extract Exhibits Antiwrinkle Activity by Suppressing ErbB2 Phosphorylation

Umbilicaria esculenta (UE), an edible lichen, is widespread in northeast Asian countries, including China, Japan, and Korea. In the present study, we examined the antiwrinkle activity of UE. We observed that the UE extract (UEE) suppressed ultraviolet (UV)-induced matrix metalloprotein-1 (MMP-1) expression and reactive oxygen species (ROS) generation in a human keratinocyte cell line (HaCaT) and human skin tissue. In addition, UEE reversed the UV-induced decrease in collagen in the human skin tissue. Excessive and chronic UV exposure is a key factor underlying skin wrinkle formation via MMP-1 expression. As treatment with UEE disrupted the UV-activated mitogen-activated protein kinase (MAPK) signaling pathway, we applied an antibody array to unveil the underlying mechanism of UEE. Interestingly, UEE treatment inhibited ErbB2 phosphorylation, but not epidermal growth factor receptor phosphorylation, a heterodimerization partner with ErbB2. Furthermore, UEE treatment enhanced UV-suppressed phosphatase activity via ROS suppression. Collectively, our findings indicate that UEE enhances ErbB2 dephosphorylation to suppress UV-induced MMP-1 expression.

Ginsenoside Rf Enhances Exercise Endurance by Stimulating Myoblast Differentiation and Mitochondrial Biogenesis in C2C12 Myotubes and ICR Mice

Ginsenoside Rf (G-Rf) is a saponin of the protopanaxatriol family and a bioactive component of Korean ginseng. Several ginsenosides are known to have a positive effect on exercise endurance, but there is not yet a report on that of G-Rf. Forced swimming tests were performed on G-Rf-treated mice to evaluate the effect of G-Rf on exercise endurance. Subsequently, the expression of markers related to myoblast differentiation and mitochondrial biogenesis in murine skeletal C2C12 myotubes and tibialis anterior muscle tissue was determined using Western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence staining to elucidate the mechanism of action of G-Rf. The swimming duration of the experimental animal was increased by oral gavage administration of G-Rf. Moreover, G-Rf significantly upregulated the myoblast differentiation markers, mitochondrial biogenesis markers, and its upstream regulators. In particular, the mitochondrial biogenesis marker increased by G-Rf was decreased by each inhibitor of the upstream regulators. G-Rf enhances exercise endurance in mice, which may be mediated by myoblast differentiation and enhanced mitochondrial biogenesis through AMPK and p38 MAPK signaling pathways, suggesting that it increases energy production to satisfy additional needs of exercising muscle cells. Therefore, G-Rf is an active ingredient in Korean ginseng responsible for improving exercise performance.

By-product of Korean liquor fermented by Saccharomyces cerevisiae exhibits skin whitening activity

Herein, the skin whitening effect of the fermentation residue of Saccharomyces cerevisiae was investigated. The fermentation residue showed radical scavenging activity and attenuated tyrosinase activity. Furthermore, the fermentation residue of S. cerevisiae significantly suppressed melanin generation in B16F10 cells. Interestingly, the sample-containing formulation exhibited increased skin whitening activity compared with that by the control formulation in a clinical study. Notably, the endogenous tyrosinase expression was not altered by the fermentation residue of S. cerevisiae; however, the enzymatic activity of tyrosinase was inhibited. Furthermore, the sample did not change TRP1 and TRP2 expression in B16F10 cells. Thus, the fermentation residue of S. cerevisiae was assumed to directly suppress the tyrosinase enzyme. It was confirmed that the fermentation residue of S. cerevisiae was a competitive inhibitor of tyrosinase. Taken together, the fermentation residue of S. cerevisiae could be a novel skin whitening agent originating from the traditional Korean liquor production process.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01062-7.

Effect of Characterized Green Tea Extraction Methods and Formulations on Enzymatic Starch Hydrolysis and Intestinal Glucose Transport

The purpose of the current study was to investigate the effect of various characterized green tea extracts (GTEs) according to extraction methods on enzymatic starch hydrolysis and intestinal glucose transport. Codigestion of wheat starch with water extract (WGT) or ethanol extract formulated with green tea polysaccharides and flavonols (CATEPLUS) produced 3.4-3.5 times higher resistant starch (RS) than wheat starch only. Its microstructures were changed to spherical shapes and smooth surfaces as shown by scanning electron microscopy (SEM) results. According to Fourier transform infrared (FT-IR) spectra, the absorption peak of O-H stretching was red-shifted in WGT or CATEPLUS. The results confirmed that hydrogen bonds were formed between starch granules and polysaccharides in WGT or CATEPLUS. Intestinal glucose transport subsequently measured after in vitro digestion was mostly suppressed in CATEPLUS. Gene expression of the glucose transporter protein, particularly SGLT1, was significantly inhibited by addition of CATEPLUS (p < 0.05). Results from the current study suggest that co-intake of green tea extracts formulated with green tea polysaccharides and flavonols could be a potentially useful means to delay blood glucose absorption when consuming starchy foods.

Oral Administration of Rosa gallica Prevents UVB-Induced Skin Aging through Targeting the c-Raf Signaling Axis

Rosa gallica is a widely used Rosa species for medicinal and culinary purposes. Rosa gallica has been reported to display antioxidant, anti−inflammatory, and antibacterial activities. However, the effect of Rosa gallica against skin aging in vivo is unknown and its active components have not been fully understood. Oral administration of Rosa gallica prevented UVB−mediated skin wrinkle formation and loss of collagen/keratin fibers in the dorsal skin of mice. Examination of biomarkers at the molecular level showed that Rosa gallica downregulates UVB−induced COX−2 and MMP−1 expression in the skin. Through a direct comparison of major compounds identified using the UHPLC−MS/MS system, we discovered gallic acid as the primary component contributing to the anti-skin aging effect exhibited by Rosa gallica. Examination of the molecular mechanism revealed that gallic acid can potently and selectively target the c−Raf/MEK/ERK/c−Fos signaling axis. In addition, both gallic acid and MEK inhibitor blocked UVB−induced MMP−1 expression and restored collagen levels in a reconstructed 3D human skin model. Collectively, Rosa gallica could be used as a functional ingredient in the development of nutraceuticals against skin aging.

Inhibitory effect of Saccharomyces cerevisiae extract obtained through ultrasound-assisted extraction on melanoma cells

Although the immune enhancing effect of yeast has been widely reported, studies specifically investigating its effects on skin cancer are lacking. Therefore, this study aimed to develop a yeast extract capable of inhibiting melanoma cells using ultrasound technology, which can lyse the cell walls allowing subsequent rapid yeast extraction. To compare the extraction efficiency across different extraction methods, the total yield, as well as total glucan, α-glucan, and β-glucan yields were measured. Ultrasound-assisted extract of yeast (UAEY) was found to effectively inhibit melanoma cell growth and proliferation as well as the expression of cyclin D1 and c-myc, in vitro. Additionally, the extract reduced melanoma tumor volume and cyclin D1 levels in BALB/c nu/nu mice. The optimal extraction conditions were 0.2 M NaOH, 3 h, 70 °C, 20 kHz, and 800 W, resulting in an increased total extraction and β-glucan yields of 73.6% and 7.1%, respectively, compared with that achieved using a conventional chemical (0.5 M NaOH) extraction method. Taken together, the results of this study suggest that UAEY may represent an effective anti-skin cancer agent.

Rose (Rosa gallica) Petal Extract Suppress Proliferation, Migration, and Invasion of Human Lung Adenocarcinoma A549 Cells through via the EGFR Signaling Pathway

We sought to investigate the effect of rose petal extract (RPE) on the proliferation, migration, and invasion of cancer cells. RPE significantly inhibited the growth of lung and colorectal cancer cell lines, with rapid suppression of A549 lung cancer cells at low concentrations. These effects occurred concomitantly with downregulation of the cell proliferation mediators PCNA, cyclin D1, and c-myc. In addition, RPE suppressed the migration and invasion of A549 cells by inhibiting the expression and activity of matrix metalloproteinase-2 and matrix metalloproteinase-9 (MMP-2 and -9). We hypothesize that the suppressive activity of RPE against lung cancer cell proliferation and early metastasis occurs via the EGFR-MAPK and mTOR-Akt signaling pathways. These early results highlight the significant potency of RPE, particularly for lung cancer cells, and warrant further investigation.

Rose Petal Extract (Rosa gallica) Exerts Skin Whitening and Anti-Skin Wrinkle Effects

We sought to investigate the effect of extracts from Rosa gallica petals (RPE) on skin whitening and anti-wrinkle activity. Tyrosinase activity was attenuated by RPE treatment, concomitant with the reduction of melanin accumulation in human B16F10 melanoma. Treatment of the facial skin of volunteers in a clinical trial with an RPE-containing formulation enhanced skin brightness (L* value) significantly. The underlying mechanism responsible was determined to be associated with mitogen-activated protein kinase (MAPK) activation. In addition, RPE exhibited anti-wrinkle formation activity of human dermal fibroblasts by suppressing matrix metalloproteinase (MMP)-1 level. In vivo study, RPE also inhibited solar ultraviolet-stimulated MMP-1 level by c-Jun regulation. Overall, our findings indicate that RPE evokes skin whitening and anti-wrinkle formation activity by regulating intracellular signaling, supporting its utility as an ingredient for skin whitening and anti-wrinkle cosmetic products.

Silk peptide production from whole silkworm cocoon using ultrasound and enzymatic treatment and its suppression of solar ultraviolet-induced skin inflammation

Silk fibroin, which is derived from sericin through degumming, is mainly used as a biomaterial. However, interest in functional verification and industrial applications of sericin has been growing for several years. We used ultrasonication to simplify the extraction process of the silk peptide under low salt conditions at 20 °C, instead of using the conventional conditions of high salt and temperature. The concentration of the silk peptide was measured to determine the optimized extraction time and solvent, which were 4 h and 0.1 N NaOH, respectively. The molecular weight of the enzyme-treated silk peptide was measured using SDS-PAGE and GPC. Silk peptide treated with papain after ultrasound had a molecular weight of less than 5 kDa, and the papain treated-silk peptide reduced solar ultraviolet-induced COX-2 expression through inhibition of ERK phosphorylation. This is the first study investigating simultaneous extraction of fibroin and sericin, which can be used for mass production of food materials.

Red Ginseng Improves Exercise Endurance by Promoting Mitochondrial Biogenesis and Myoblast Differentiation

Red ginseng has been reported to elicit various therapeutic effects relevant to cancer, diabetes, neurodegenerative diseases, and inflammatory diseases. However, the effect of red ginseng on exercise endurance and skeletal muscle function remains unclear. Herein, we sought to investigate whether red ginseng could affect exercise endurance and examined its molecular mechanism. Mice were fed with red ginseng extract (RG) and undertook swimming exercises to determine the time to exhaustion. Animals fed with RG had significantly longer swimming endurance. RG treatment was also observed to enhance ATP production levels in myoblasts. RG increased mRNA expressions of mitochondrial biogenesis regulators, NRF-1, TFAM, and PGC-1α, which was accompanied by an elevation in mitochondrial DNA, suggesting an enhancement in mitochondrial energy-generating capacity. Importantly, RG treatment induced phosphorylation of p38 and AMPK and upregulated PGC1α expression in both myoblasts and in vivo muscle tissue. In addition, RG treatment also stimulated C2C12 myogenic differentiation. Our findings show that red ginseng improves exercise endurance, suggesting that it may have applications in supporting skeletal muscle function and exercise performance.

Abstract 1770: RSK2 is required for TRAF6 phosphorylation-mediated colon inflammation

Inflammation is a complex biological host reaction to tissue damage, infection and trauma. Extensive study of the inflammatory response has led to the identification of several protein kinases that are essential for signaling and could be potential therapeutic targets. The RSK family of kinases has multiple cellular functions. In our study, we found that RSK2 is a mediator for inflammation signaling and interacts with TRAF6. In vitro kinase assay results indicated that RSK2 strongly phosphorylates TRAF6 at serines 46, 47 and 48. Ectopic over-expression of TRAF6 or knocking down RSK2 expression confirmed that RSK2 is a positive regulator of TRAF6 K63 ubiquitination. TRAF6 is also required for RSK2 ubiquitination. TRAF6 bridges the TNF receptor superfamily and intracellular signaling for the induction of pro-inflammatory cytokines. We developed a colon inflammation model using RSK2 wild type (WT) and knockout (KO) mice. As expected, F4/80 and CD3 infiltration were significantly upregulated in WT mice compared to RSK2 KO mice. Furthermore, inflammation signaling, including Ikkα/β, p38 and JNKs, was dramatically up-regulated in WT mice. Colon tissue immunoprecipitation results further confirmed that TRAF6 K63 ubiquitination was lower in RSK2 KO mice. Overall, these results indicate that phosphorylation of TRAF6 (S46, 47, 48) by RSK2 is required for TRAF6 K63 ubiquitination and inflammation signaling.

Citation Format: Ke Yao, Sung-Young Lee, Cong Peng, Do Young Lim, Hiroyuki Yamamoto, Joohyun Ryu, Tae-Gyu Lim, Hanyong Chen, Wei-Ya Ma, Ann M. Bode, Zigang Dong. RSK2 is required for TRAF6 phosphorylation-mediated colon inflammation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1770.

Determining pesticide residues in wheat flour by ultrahigh-performance liquid chromatography/quadrupole time-of-flight mass spectrometry with QuEChERS extraction

Pesticides are used to increase crop yields and preserve quality by protecting crops against pests; however, their overuse can adversely affect human health and the environment. Herein, we report the development of a multi-pesticide screening method using optimized QuEChERS coupled with liquid chromatography/quadrupole time-of-flight (QTOF) mass spectrometry for the analysis of 13 pesticides in wheat flour. Mass accuracies with errors of less than 2.4 ppm were obtained for all analysed pesticides, and the method provided satisfactory recovery and linearity. Repeatabilities of 0.3-12.7% and reproducibilities of 2.5-15.2% were observed in full-scan TOF mode. The performance of the developed full-scan TOF method was compared to that obtained in high-resolution multiple reaction monitoring (MRM-HR) mode. The limits of quantification for the full-scan TOF and MRM-HR modes ranged from 2 to 10, and 3 to 9 μg kg^-1, respectively. The two quantification methods exhibited high sensitivities (limit of detections: 1-3 μg kg^-1 in full-scan TOF, and 1-3 μg kg^-1 for MRM-HR mode). No pesticide residues were detected when the developed method was applied to 22 real wheat flour samples.

Caffeic Acid Phenethyl Ester Inhibits UV-Induced MMP-1 Expression by Targeting Histone Acetyltransferases in Human Skin

Caffeic acid phenethyl ester (CAPE), a naturally occurring bioactive compound, displays anti-inflammatory, anti-carcinogenic, and anti-microbial effects. However, the effect of CAPE on skin photoaging is unknown. Herein, we investigated the inhibitory effect of CAPE against ultraviolet (UV) irradiation-mediated matrix metalloproteinase (MMP)-1 expression and its underlying molecular mechanism. CAPE treatment suppressed UV-induced MMP-1 levels in both human dermal fibroblasts (HDF) and human skin tissues. While CAPE did not display any significant effects against the upstream regulatory pathways of MMP-1, CAPE was capable of reversing UV-mediated epigenetic modifications. CAPE suppressed UV-induced acetyl-histone H3 (Lys9) as well as total lysine acetylation in HDF cells. Similarly, CAPE also attenuated UV-induced lysine acetylations in human skin tissues, suggesting that the CAPE-mediated epigenetic alterations can be recapitulated in ex vivo conditions. CAPE was found to attenuate UV-induced histone acetyltransferase (HAT) activity in HDF. Notably, CAPE was able to directly inhibit the activity of several HATs including p300, CREP-binding protein (CBP), and p300/CBP-associated factor (PCAF), further confirming that CAPE can function as an epigenetic modulator. Thus, our study suggests that CAPE maybe a promising agent for the prevention of skin photoaging via targeting HATs.

Isolation, purification, and characterization of novel polysaccharides from lotus (Nelumbo nucifera) leaves and their immunostimulatory effects

In this study, a crude water-soluble polysaccharide (LLWP-C) was extracted from lotus leaves and further purified by size exclusion chromatography, to obtain the two main polysaccharides, LLWP-1 and LLWP-3. Physical and chemical analyses showed that they were homogeneous polysaccharides in β-type glycosidic linkage. LLWP-1 was devoid of helical conformation, had a molecular weight of 85.1 kDa and was mainly composed of Rha, Ara, Gal, Glu, and GalA in a molar ratio of 7.0:24.8:28.0:6.0:26.4. LLWP-3 showed a helical conformation, had a molecular weight of 12.5 kDa and consisted mainly of Rha, Ara, Gal, Glu, Man, and GalA in a molar ratio of 6.6:9.8:15.0:8.9:6.1:47.2. It was demonstrated that LLWP-C and both purified LLWP-1 and LLWP-3 could effectively enhance the proliferation, phagocytosis, nitric oxide (NO), and cytokine secretions by activating corresponding mRNA expression in macrophages, via MAPK and NF-κB pathways. LLWP-3 displayed the greatest immunostimulatory potential, followed by LLWP-1 and LLWP-C. These findings suggest that polysaccharides extracted from lotus leaf exert immunostimulatory activity that could be further investigated to develop functional foods and natural immunopotentiating therapeutic agents.

Inhibitory Effect of Opuntia humifusa Fruit Water Extract on Solar Ultraviolet-Induced MMP-1 Expression

Opuntia humifusa is a type of cactus whose fruits have been used in folk medicine for the treatment of several diseases. In the present study, we aimed to determine whether O. humifusa fruit water extract (OHE) has inhibitory effects against solar ultraviolet (sUV)-induced matrix metalloproteinase-1 (MMP-1) expression. In ex vivo human skin, we found that OHE suppressed sUV radiation-induced MMP-1 expression. The inhibitory effect of OHE was confirmed in human dermal fibroblasts. OHE treatment reduced sUV-induced MMP-1 expression by suppressing reactive oxygen species (ROS) generation and phosphorylation of c-Jun, a component of transcription factor activator protein 1 (AP-1). On the other hand, OHE recovered the tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) and type 1 collagen production attenuated by sUV. As upstream signaling pathways for AP-1, MKK4-JNK, MEK-ERK, and MKK3/6-p38 phosphorylation were downregulated by OHE treatment. In addition, OHE exhibited DPPH radical scavenging activity. These findings demonstrate that OHE has a preventive effect against sUV-induced skin damage via suppression of pathways triggered by ROS.

Antiskin Inflammatory Activity of Black Ginger (Kaempferia parviflora) through Antioxidative Activity

Kaempferia parviflora (Krachaidum (KD)) is a traditional herbal medicine and has properties that are beneficial for human health. In the current study, we sought to investigate the anti-inflammatory properties of KD extract (KPE). In mouse skin tissue, UV light representing solar wavelengths (sUV) increased COX-2 expression, while treatment with KPE reduced this effect. The anti-inflammatory activity of KPE was confirmed in in vitro models. MAPK signaling pathways were activated by sUV irradiation, and this was also repressed in the presence of KPE treatment. It is assumed that the anti-inflammatory activity of KPE is caused by the antioxidative effect. Furthermore, we confirmed the critical role of oxidative stress in sUV-induced COX-2 expression. We analyzed the polyphenol composition of KPE. Of the polyphenols identified, gallic acid, apigenin, and tangeretin were identified as the major polyphenols (at 9.31 ± 1.27, 2.37 ± 0.14, and 2.15 ± 0.19 μg/mg dry weight, resp.). Collectively, these findings show that in the presence of sUV irradiation, KD has anti-inflammatory properties and antioxidative effects in the skin.

The clinical utility of Xpert® MTB/RIF testing in induced sputum

We performed a prospective clinical audit in hospitalised patients with suspected pulmonary tuberculosis (PTB) with the objective of evaluating the accuracy and clinical utility of Xpert® MTB/RIF in induced sputum in an intermediate-burden setting. Of 450 patients audited, 61 (13.6%) were diagnosed with PTB based on positive culture. The sensitivity, specificity and positive and negative predictive values for Xpert in smear-negative cases for induced sputum were respectively 75%, 99.5%, 94.7% and 97.0%. Xpert in induced sputum may facilitate diagnostic yield and expedite treatment in up to a quarter of PTB patients.

Mixing ratio optimization for functional complex extracts of Rhodiola crenulata, Panax quinquefolius, and Astragalus membranaceus using mixture design and verification of immune functional efficacy in animal models

We aimed to identify the optimum mixing ratio for various ingredients to obtain complex extracts with high extract yields and immune-enhancing activity in animals. The extract yield and amounts of nitric oxide (NO) and interleukin (IL)-6 were set to maximum for modeling predictions. The predicted optimum values for the mixing ratio were 49.5% for Rhodiola crenulata, 26.1% for Astragalus membranaceus, and 24.4% for Panax quinquefolius, and the predicted response values were 31.5% yield, 13.4% NO production, and 6.1% IL-6 production; actual values were 35.3% yield, 14.7% NO, and 6.6% IL-6. The optimum mixing ratio extract (OMRE) was used for the animal experiments. Treating mice with OMRE at 200 mg/kg produced significant increases in spleen indexes and T-cell/B-cell proliferation. OMRE treatment increased IL-10 and IL-6 production in concanavalin A- and lipopolysaccharide-induced T- and B- lymphocytes, respectively. These results provide a basis for the development of functional extracts and drinks.

The Ginsenoside Derivative 20(S)-Protopanaxadiol Inhibits Solar Ultraviolet Light-Induced Matrix Metalloproteinase-1 Expression

Ginsenosides are major pharmacologically active compounds present in ginseng (Panax ginseng). Among the ginsenosides, 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (GPPD) and ginsenoside Rb1 (Rb1) have previously been reported to exhibit anti-wrinkle effects. In this study, 20(S)-protopanaxadiol (20(S)-PPD), an aglycone derivative of the Rb1 metabolite was investigated for its anti-wrinkle benefit and compared to GPPD and Rb1. The anti-wrinkle effect of 20(S)-PPD during solar UV light was investigated using a human skin equivalent model and human keratinocytes. 20(S)-PPD attenuated solar UV-induced matrix metalloproteinase (MMP)-1 expression to a greater extent than GPPD and Rb1. 20(S)-PPD treatment modulated MMP-1 mRNA expression and the transcriptional activity of activator protein (AP)-1, a major transcription factor of MMP-1. Two upstream signaling pathways for AP-1, the MEK1/2-ERK1/2-p90^RSK and MEK3/6-p38 pathways, were also suppressed. Taken together, these findings highlight the potential of 20(S)-PPD for further development as a preventative agent for sunlight-induced skin wrinkle. J. Cell. Biochem. 118: 3756-3764, 2017. © 2017 Wiley Periodicals, Inc.

The Prolyl Isomerase Pin1 Is a Novel Target of 6,7,4'-Trihydroxyisoflavone for Suppressing Esophageal Cancer Growth

Intake of soy isoflavones is inversely associated with the risk of esophageal cancer. Numerous experimental results have supported the anticancer activity of soy isoflavones. This study aimed to determine the anti-esophageal cancer activity of 6,7,4'-trihydroxyisoflavone (6,7,4'-THIF), a major metabolite of daidzein, which is readily metabolized in the human body. Notably, 6,7,4'-THIF inhibited proliferation and increased apoptosis of esophageal cancer cells. On the basis of a virtual screening analysis, Pin1 was identified as a target protein of 6,7,4'-THIF. Pull-down assay results using 6,7,4'-THIF Sepharose 4B beads showed a direct interaction between 6,7,4'-THIF and the Pin1 protein. Pin1 is a critical therapeutic and preventive target in esophageal cancer because of its positive regulation of β-catenin and cyclin D1. The 6,7,4'-THIF compound simultaneously reduced Pin1 isomerase activity and the downstream activation targets of Pin1. The specific inhibitory activity of 6,7,4'-THIF was analyzed using Neu/Pin1 wild-type (WT) and Neu/Pin1 knockout (KO) MEFs. 6,7,4'-THIF effected Neu/Pin1 WT MEFs, but not Neu/Pin1 KO MEFs. Furthermore, the results of a xenograft assay using Neu/Pin1 WT and KO MEFs were similar to those obtained from the in vitro assay. Overall, we found that 6,7,4'-THIF specifically reduced Pin1 activity in esophageal cancer models. Importantly, 6,7,4'-THIF directly bound to Pin1 but not FKBP or cyclophilin A, the same family of proteins. Because Pin1 acts like an oncogene by modulating various carcinogenesis-related proteins, this study might at least partially explain the underlying mechanism(s) of the anti-esophageal cancer effects of soy isoflavones. Cancer Prev Res; 10(5); 308-18. ©2017 AACR.

Anti-oxidative and anti-inflammatory activities of devil's club (Oplopanax horridus) leaves

This study aimed to investigate the anti-oxidative properties of the ethanolic extracts of the devil's club (Oplopanax horridus) leaves, stems, and roots. Furthermore, the anti-inflammatory activity of the leaf extract was analyzed. The leaf extract had higher total phenolic and flavonoid contents and anti-oxidative activity (radical scavenging, reducing power, and inhibition of lipid oxidation) than the root and stem extracts. The leaf extract also had anti-inflammatory effects. It significantly reduced lipopolysaccharide (LPS)-induced nitric oxide (NO; 71.0% at 50 μg/mL), tumor necrosis factor (TNF)-α (87.6% at 100 μg/mL), and interleukin (IL)-6 (36.2% at 100 μg/mL) production in murine RAW 264.7 macrophages. Furthermore, LPS-induced inducible nitric oxide synthase (iNOS) expression was decreased by the leaf extract (IC50=24.4 μg/mL). The ultra performance liquid chromatography-diode array detector (UPLC-DAD) analysis showed that the leaf extract contained gallic acid, protocatechuic acid, chlorogenic acid, and maltol. These findings suggest that the leaf extract could be utilized as a functional food material because of its anti-oxidative and anti-inflammatory activities.

White ginseng extract induces immunomodulatory effects via the MKK4-JNK pathway

Panax ginseng Meyer (white ginseng) is a popular functional food and its biological effects on the human body have been noted for hundreds of years. In the present study, the underlying mechanisms responsible for the immunomodulatory effects of white ginseng extract (WGE) were investigated. WGE increased NO production via upregulation of iNOS expression levels. Mouse cytokine array results also revealed that the expression of 13 cytokines was elevated by WGE treatment in IFN-γ-primed macrophage cells. Although both MKK4-JNK and MEK-ERK signaling pathways were activated after treatment with WGE, only the MKK4-JNK signaling pathway appears to have any significant immunomodulatory significance. Oral administration of WGE for 28 days recovered cyclophosphamide (CY)-induced suppression of the immune system in mice via the MKK4-JNK pathway. Taken together, these findings suggest that the MKK4-JNK signaling pathway is a crucial mechanism of WGE-induced immunomodulation.

Design, Synthesis, and Biological Evaluation of Quercetagetin Analogues as JNK1 Inhibitors

The recent discovery of c-Jun NH2-terminal kinase JNK1 suppression by natural quercetagetin (1) is a promising lead for the development of novel anticancer agents. Using both X-ray structure and docking analyses we predicted that 5'-hydroxy- (2) and 5'-hydroxymethyl-quercetagetin (3) would inhibit JNK1 more actively than the parent compound 1. Notably, our drug design was based on the active enzyme-ligand complex as opposed to the enzyme's relatively open apo structure. In this paper we test our theoretical predictions, aided by docking-model experiments, and report the first synthesis and biological evaluation of quercetagetin analogues 2 and 3. As calculated, both compounds strongly suppress JNK1 activity. The IC50 values were determined to be 3.4 μM and 12.2 μM, respectively, which shows that 2 surpasses the potency of the parent compound 1 (IC50 =4.6 μM). Compound 2 was also shown to suppress matrix metalloproteinase-1 expression with high specificity after UV irradiation.

A fermented barley and soybean formula enhances skin hydration

Skin hydration is one of the primary aims of beauty and anti-aging treatments. Barley (Hordeum vulgare) and soybean (Glycine max) are major food crops, but can also be used as ingredients for the maintenance of skin health. We developed a natural product-based skin treatment using a barley and soybean formula (BS) incorporating yeast fermentation, and evaluated its skin hydration effects as a dietary supplement in a clinical study. Participants ingested a placebo- (n = 33) or BS- (3 g/day) containing drink (n = 32) for 8 weeks. A significant increase in hydration in the BS group as compared to the placebo group was observed on the faces of subjects after 4 and 8 weeks, and on the forearm after 4 weeks. Decreases in stratum corneum (SC) thickness were also observed on the face and forearm. BS enhanced hyaluronan (HA) and skin barrier function in vitro and reduced Hyal2 expression in human dermal fibroblasts (HDF). BS also recovered ultraviolet (UV) B-induced downregulation of HA in HaCaT cells. These results suggest that BS has promising potential for development as a health functional food to enhance skin health.

20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol suppresses UV-Induced MMP-1 expression through AMPK-mediated mTOR inhibition as a downstream of the PKA-LKB1 pathway

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.

20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol, a metabolite of ginsenoside Rb1, enhances the production of hyaluronic acid through the activation of ERK and Akt mediated by Src tyrosin kinase in human keratinocytes

The aim of the present study was to determine the mechanisms through which 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (20GPPD) promotes the production of hyaluronic acid (HA) in human keratinocytes. 20GPPD is the primary bioactive metabolite of Rb1, a major ginsenoside found in ginseng (Panax ginseng). We sought to elucidate the underlying mechanisms behind the 20GPPD-induced production of HA. We found that 20GPPD induced an increase in HA production by elevating hyaluronan synthase 2 (HAS2) expression in human keratinocytes. The phosphorylation of extracellular signal-regulated kinase (ERK) and Akt was also enhanced by 20GPPD in a dose-dependent manner. The pharmacological inhibition of ERK (using U0126) or Akt (using LY294002) suppressed the 20GPPD-induced expression of HAS2, whereas treatment with an epidermal growth factor receptor (EGFR) inhibitor (AG1478) or an intracellular Ca2+ chelator (BAPTA/AM) did not exert any observable effects. The increased Src phosphorylation was also confirmed following treatment with 20GPPD in the human keratinocytes. Following pre-treatment with the Src inhibitor, PP2, both HA production and HAS2 expression were attenuated. Furthermore, the 20GPPD-enhanced ERK and Akt signaling decreased following treatment with PP2. Taken together, our results suggest that Src kinase plays a critical role in the 20GPPD-induced production of HA by acting as an upstream modulator of ERK and Akt activity in human keratinocytes.

MLK3 is a novel target of dehydroglyasperin D for the reduction in UVB-induced COX-2 expression in vitro and in vivo

Dehydroglyasperin D (DHGA-D), a compound present in licorice, has been found to exhibit anti-obesity, antioxidant and anti-aldose reductase effects. However, the direct molecular mechanism and molecular targets of DHGA-D during skin inflammation remain unknown. In the present study, we investigated the effect of DHGA-D on inflammation and its mechanism of action on UVB-induced skin inflammation in HaCaT human keratinocytes and SKH-1 hairless mice. DHGA-D treatment strongly suppressed UVB-induced COX-2 expression, PGE2 generation and AP-1 transactivity in HaCaT cells without affecting cell viability. DHGA-D also inhibited phosphorylation of the mitogen-activated protein kinase kinase (MKK) 3/6/p38, MAPK/Elk-1, MKK4/c-Jun N-terminal kinase (JNK) 1/2/c-Jun/mitogen, and stress-activated protein kinase (MSK), whereas phosphorylation of the mixed-lineage kinase (MLK) 3 remained unaffected. Kinase and co-precipitation assays with DHGA-D Sepharose 4B beads showed that DHGA-D significantly suppressed MLK3 activity through direct binding to MLK3. Knockdown of MLK3 suppressed COX-2 expression as well as phosphorylation of MKK4/p38 and MKK3/6/JNK1/2 in HaCaT cells. Furthermore, Western blot assay and immunohistochemistry results showed that DHGA-D pre-treatment significantly inhibits UVB-induced COX-2 expression in vivo. Taken together, these results indicate that DHGA-D may be a promising anti-inflammatory agent that mediates suppression of both COX-2 expression and the MLK3 signalling pathway through direct binding and inhibition of MLK3.

Isoliquiritigenin induces apoptosis and inhibits xenograft tumor growth of human lung cancer cells by targeting both wild type and L858R/T790M mutant EGFR

Non-small-cell lung cancer (NSCLC) is associated with diverse genetic alterations including mutation of epidermal growth factor receptor (EGFR). Isoliquiritigenin (ILQ), a chalcone derivative, possesses anticancer activities. In the present study, we investigated the effects of ILQ on the growth of tyrosine kinase inhibitor (TKI)-sensitive and -resistant NSCLC cells and elucidated its underlying mechanisms. Treatment with ILQ inhibited growth and induced apoptosis in both TKI-sensitive and -resistant NSCLC cells. ILQ-induced apoptosis was associated with the cleavage of caspase-3 and poly-(ADP-ribose)-polymerase, increased expression of Bim, and reduced expression of Bcl-2. In vitro kinase assay results revealed that ILQ inhibited the catalytic activity of both wild type and double mutant (L858R/T790M) EGFR. Treatment with ILQ inhibited the anchorage-independent growth of NIH3T3 cells stably transfected with either wild type or double-mutant EGFR with or without EGF stimulation. ILQ also reduced the phosphorylation of Akt and ERK1/2 in both TKI-sensitive and -resistant NSCLC cells, and attenuated the kinase activity of Akt1 and ERK2 in vitro. ILQ directly interacted with both wild type and double-mutant EGFR in an ATP-competitive manner. A docking model study showed that ILQ formed two hydrogen bonds (Glu-762 and Met-793) with wild type EGFR and three hydrogen bonds (Lys-745, Met-793, and Asp-855) with mutant EGFR. ILQ attenuated the xenograft tumor growth of H1975 cells, which was associated with decreased expression of Ki-67 and diminished phosphorylation of Akt and ERK1/2. Taken together, ILQ suppresses NSCLC cell growth by directly targeting wild type or mutant EGFR.

Curcumin suppresses proliferation of colon cancer cells by targeting CDK2

Curcumin, the yellow pigment of turmeric found in Southeast Indian food, is one of the most popular phytochemicals for cancer prevention. Numerous reports have demonstrated modulation of multiple cellular signaling pathways by curcumin and its molecular targets in various cancer cell lines. To identify a new molecular target of curcumin, we used shape screening and reverse docking to screen the Protein Data Bank against curcumin. Cyclin-dependent kinase 2 (CDK2), a major cell-cycle protein, was identified as a potential molecular target of curcumin. Indeed, in vitro and ex vivo kinase assay data revealed a dramatic suppressive effect of curcumin on CDK2 kinase activity. Furthermore, curcumin induced G1 cell-cycle arrest, which is regulated by CDK2 in HCT116 cells. Although the expression levels of CDK2 and its regulatory subunit, cyclin E, were not changed, the phosphorylation of retinoblastoma (Rb), a well-known CDK2 substrate, was reduced by curcumin. Because curcumin induced cell-cycle arrest, we investigated the antiproliferative effect of curcumin on HCT116 colon cancer cells. In this experiment, curcumin suppressed HCT116 cell proliferation effectively. To determine whether CDK2 is a direct target of curcumin, CDK2 expression was knocked down in HCT116 cells. As expected, HCT116 sh-CDK2 cells exhibited G1 arrest and reduced proliferation. Because of the low levels of CDK2 in HCT116 sh-CDK2 cells, the effects of curcumin on G1 arrest and cell proliferation were not substantially relative to HCT116 sh-control cells. From these results, we identified CDK2 as a direct target of curcumin in colon cancer cells.

NADPH oxidase is a novel target of delphinidin for the inhibition of UVB-induced MMP-1 expression in human dermal fibroblasts

We investigated the reported antiphotoaging effects of the major anthocyanidin delphidin and sought to identify its specific molecular target during UVB-induced MMP-1 expression. Delphinidin treatment significantly inhibited UVB-induced MMP-1 expression in primary cultured human dermal fibroblasts (HDF), an effect associated with the suppression of MKK4-JNK1/2, MKK3/6-p38 and MEK-ERK1/2 phosphorylation. Further investigation revealed that delphinidin significantly inhibited UVB-induced ROS production and NOX activity. Interestingly, the inhibitory effect of delphinidin on UVB-induced NOX activity was stronger than that of apocynin, a pharmaceutical NOX inhibitor. Fractioned cell analysis results using a Western blot assay showed that this effect occurred through the inhibition of UVB-induced P47(phox) (a NOX subunit) translocation from the cytosol to the membrane. Pull down assays demonstrated that delphinidin binds directly to P47(phox) in vitro. Collectively, our results suggest that delphinidin targets NOX, resulting in the suppression of UVB-induced MMP-1 expression in human dermal fibroblasts.

Enhancement of anti-inflammatory activity of Aloe vera adventitious root extracts through the alteration of primary and secondary metabolites via salicylic acid elicitation

Aloe vera (Asphodeloideae) is a medicinal plant in which useful secondary metabolites are plentiful. Among the representative secondary metabolites of Aloe vera are the anthraquinones including aloe emodin and chrysophanol, which are tricyclic aromatic quinones synthesized via a plant-specific type III polyketide biosynthesis pathway. However, it is not yet clear which cellular responses can induce the pathway, leading to production of tricyclic aromatic quinones. In this study, we examined the effect of endogenous elicitors on the type III polyketide biosynthesis pathway and identified the metabolic changes induced in elicitor-treated Aloe vera adventitious roots. Salicylic acid, methyl jasmonate, and ethephon were used to treat Aloe vera adventitious roots cultured on MS liquid media with 0.3 mg/L IBA for 35 days. Aloe emodin and chrysophanol were remarkably increased by the SA treatment, more than 10-11 and 5-13 fold as compared with untreated control, respectively. Ultra-performance liquid chromatography-electrospray ionization mass spectrometry analysis identified a total of 37 SA-induced compounds, including aloe emodin and chrysophanol, and 3 of the compounds were tentatively identified as tricyclic aromatic quinones. Transcript accumulation analysis of polyketide synthase genes and gas chromatography mass spectrometry showed that these secondary metabolic changes resulted from increased expression of octaketide synthase genes and decreases in malonyl-CoA, which is the precursor for the tricyclic aromatic quinone biosynthesis pathway. In addition, anti-inflammatory activity was enhanced in extracts of SA-treated adventitious roots. Our results suggest that SA has an important role in activation of the plant specific-type III polyketide biosynthetic pathway, and therefore that the efficacy of Aloe vera as medicinal agent can be improved through SA treatment.

Esculetin suppresses proliferation of human colon cancer cells by directly targeting β-catenin

The Wnt pathway is a promising therapeutic and preventive target in various human cancers. The transcriptional complex of β-catenin-T-cell factor (Tcf), a key mediator of canonical Wnt signaling, has been implicated in human colon cancer development. Current treatment of colon cancer depends on traditional cytotoxic agents with limited effects. Therefore, the identification of natural compounds that can disrupt the β-catenin-TcF complex to suppress cancer cell growth with fewer adverse side effects is needed. To identify compounds that inhibit the association between β-catenin and Tcf, we used computer docking to screen a natural compound library. Esculetin, also known as 6,7-dihydroxycoumarin, is a derivative of coumarin and was identified as a potential small-molecule inhibitor of the Wnt-β-catenin pathway. We then evaluated the effect of esculetin on the growth of various human colon cancer cell lines and its effect on Wnt-β-catenin signaling in cells and in an embryonic model. Esculetin disrupted the formation of the β-catenin-Tcf complex through direct binding with the Lys312, Gly307, Lys345, and Asn387 residues of β-catenin in colon cancer cells. In addition, esculetin effectively decreased viability and inhibited anchorage-independent growth of colon cancer cells. Esculetin potently antagonized the cellular effects of β-catenin-dependent activity, and in vivo treatment with esculetin suppressed tumor growth in a colon cancer xenograft mouse model. Our data indicate that the interaction between esculetin and β-catenin inhibits the formation of the β-catenin-Tcf complex, which could contribute to esculetin's positive therapeutic and preventive effects against colon carcinogenesis.