Neuroprotective effect of isovaleraldehyde accompanied with upregulation of BDNF and CREB phosphorylation via the PKA pathway.

Recently, the number of patients diagnosed with dementia has increased. The World Health Organization (WHO) estimates that 50 million patients suffer from dementia. Although several therapeutic strategies have been proposed, currently, there is no curative approach for treating dementia. Neurodegeneration is an irreversible process. As this disease gradually progresses over 15-20 years, a low-cost and sustainable method for preventing these diseases is desired. Cacao nib is consumed in many countries, and a recent clinical study indicated that cocoa intake upregulates brain-derived neurotrophic factor (BDNF), which plays a significant role in memory formation and neuronal cell survival. In the present study, neural cells were treated with cacao nib extract or the 17 characteristic components of cacao nib. Treatment with Cacao nib extract upregulates BDNF mRNA expression. In addition, cacao nib extract elicits the phosphorylation of cAMP-response-element-binding protein (CREB), which regulates the transcription of BDNF. Among the 17 species screened, isovaleraldehyde (IVA), also known as an aroma component of cacao nibs extract, improved BDNF mRNA expression without SH-SY5Y cell toxicity. IVA also promoted CREB phosphorylation through a cAMP-dependent protein kinase (PKA)-dependent mechanism. In conclusion, IVA could be responsible for the BDNF upregulation effect of cacao nib, and IVA upregulated BDNF expression via the PKA-CREB axis.

67-kDa laminin receptor mediates oolonghomobisflavan B-induced cell growth inhibition in melanoma.

BACKGROUND: Oolonghomobisflavans are unique polyphenols found in oolong teas. Oolonghomobisflavan B (OHBFB), a dimer of (-)-epigallocatechin-3-O-gallate (EGCG), is an active compound found in green tea. PURPOSE: OHBFB has been reported to exert an inhibitory effect on lipase enzyme activity. However, little is known regarding its intercellular signaling induction effect. Further, there are no reports describing the anti-cancer effects of OHBFB. METHODS: The effect of OFBFB on B16 melanoma cells was evaluated by cell counting, and its mechanisms were determined by western blot analysis with or without protein phosphatase 2A (PP2A) inhibitor treatment. Intracellular cyclic adenosine monophosphate (cAMP) levels were evaluated by time-resolved fluorescence resonance energy transfer analysis. Quartz crystal microbalance (QCM) analysis was performed to assess the binding of OHBFB to 67LR. RESULTS: Cell growth assay and western blot analyses showed that OHBFB inhibited melanoma cell growth, followed by myosin phosphatase target subunit 1 (MYPT1) and myosin regulatory light chain (MRLC) dephosphorylation via protein phosphatase 2A (PP2A)-dependent mechanisms. These effects are mediated by intracellular cAMP- and protein kinase A (PKA) A-dependent mechanisms. QCM analysis identified the 67-kDa laminin receptor (67LR) as an OHBFB receptor with a Kd of 3.7 µM. We also demonstrated for the first time that OHBFB intake suppresses tumor growth in vivo. CONCLUSIONS: Taken together, these results indicate that the cAMP/PKA/PP2A/MYPT1/MRLC pathway is a key mediator of melanoma cell growth inhibition following OHBFB binding to 67LR and that OHBFB suppresses tumor growth in vivo.

Bioactivity-boosting strategy based on combination of anti-allergic O-methylated catechin with a Citrus flavanone, hesperetin.

Many patients with allergies have anxiety about taking anti-allergic medicines due to their side effects and increased medical expenses. Thus, developing functional foods/agricultural products for allergy prevention is strongly desired. In this study, we revealed that a Citrus flavanone, hesperetin, amplified IgE/antigen-mediated degranulation-inhibitory potency of anti-allergic catechin, (-)-epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3''Me), in the rat basophilic/mast cell line RBL-2H3. Hesperetin also significantly elevated the activation of acid sphingomyelinase (ASM), essential for eliciting anti-allergic effect of EGCG3''Me through the cell surficial protein, 67-kDa laminin receptor (67LR). Furthermore, oral administration of the highly absorbent hesperidin, α-glucosyl hesperidin, also enhanced the inhibitory potency of EGCG3''Me-rich 'Benifuuki' green tea (Camellia sinensis L.) on passive cutaneous anaphylaxis (PCA) reaction evoked by IgE/antigen in BALB/c mice. These observations indicate that hesperetin amplifies the ability of EGCG3''Me to inhibit the IgE/antigen-mediated degranulation through activating ASM signaling.

67-kDa Laminin Receptor-Mediated Cellular Sensing System of Green Tea Polyphenol EGCG and Functional Food Pairing.

The body is equipped with a "food factor-sensing system" that senses food factors, such as polyphenols, sulfur-containing compounds, and vitamins, taken into the body, and plays an essential role in manifesting their physiological effects. For example, (-)-epigallocatechin-3-O-gallate (EGCG), the representative catechin in green tea (Camellia sinensi L.), exerts various effects, including anti-cancer, anti-inflammatory, and anti-allergic effects, when sensed by the cell surficial protein 67-kDa laminin receptor (67LR). Here, we focus on three representative effects of EGCG and provide their specific signaling mechanisms, the 67LR-mediated EGCG-sensing systems. Various components present in foods, such as eriodictyol, hesperetin, sulfide, vitamin A, and fatty acids, have been found to act on the food factor-sensing system and affect the functionality of other foods/food factors, such as green tea extract, EGCG, or its O-methylated derivative at different experimental levels, i.e., in vitro, animal models, and/or clinical trials. These phenomena are observed by increasing or decreasing the activity or expression of EGCG-sensing-related molecules. Such functional interaction between food factors is called "functional food pairing". In this review, we introduce examples of functional food pairings using EGCG.

Metabolic Profiling for Evaluating the Dipeptidyl Peptidase-IV Inhibitory Potency of Diverse Green Tea Cultivars and Determining Bioactivity-Related Ingredients and Combinations.

There are numerous cultivars of tea (Camellia sinensis L.), but the differences in their anti-hyperglycemic-related effects are largely unknown. The inhibition of the dipeptidyl peptidase (DPP)-IV enzyme plays an essential role in controlling hyperglycemia in diabetes by blocking the degradation of incretin hormones, which is necessary for insulin secretion. In this study, we examined the DPP-IV inhibitory activity of leaf extracts from diverse Japanese green tea cultivars. The inhibitory rates differed among tea extracts. Metabolic profiling (MP), using liquid chromatography-mass spectrometry, of all cultivars revealed compositional differences among cultivars according to their DPP-IV inhibitory capacity. Epigallocatechin-3-O-(3-O-methyl)gallate, kaempferol-3-O-rutinoside, myricetin-3-O-glucoside/galactoside, and theogallin were newly identified as DPP-IV inhibitors. The bioactivity of a tea extract was potentiated by adding these ingredients in combination. Our results show that MP is a useful approach for evaluating the DPP-IV inhibitory potency of green tea and for determining bioactivity-related ingredients and combinations.

Fustin, a Flavanonol, Synergically Potentiates the Anticancer Effect of Green Tea Catechin Epigallocatechin-3-O-Gallate with Activation of the eNOS/cGMP Axis.

Epigallocatechin-3-O-gallate (EGCG), a catechin present in green tea, selectively elicits apoptosis in multiple myeloma cells by activating the endothelial nitric oxide synthase (eNOS)/cyclic guanosine monophosphate (cGMP) axis. However, the effects of EGCG alone are limited. Herein, we revealed that fustin, a flavanonol, enhances the EGCG-elicited activation of the cGMP/eNOS axis in multiple myeloma cells. Isobologram analysis demonstrated that EGCG/fustin synergistically elicited cell death in multiple myeloma cells. Importantly, this chemical combination significantly promoted cell death without affecting the normal cells. To assess the effects of EGCG and fustin in vivo, female BALB/c mice were inoculated with multiple myeloma MPC11 cells and then treated with each compound. The combination of EGCG/fustin suppressed tumor growth in vivo without affecting alanine aminotransferase/aspartate aminotransferase levels, the dose-limiting toxicity of EGCG. Consistent with in vitro findings, this combination increased eNOS phosphorylation at Ser1177 in the tumor. Collectively, fustin amplified EGCG-induced activation of the eNOS/cGMP axis.

Methylated (-)-epigallocatechin 3-O-gallate potentiates the effect of split vaccine accompanied with upregulation of Toll-like receptor 5.

Split-virus vaccine serves as a major countermeasure against influenza virus, but its effectiveness and protective action are not complete. We previously demonstrated the effect of Benifuuki, a green tea cultivar in Japan, on enhancing the split-virus vaccine-elicited immune response. However, little is known about the detail mechanisms. Here, we show that EGCG3"Me intake significantly potentiated the vaccine-elicited hemagglutination inhibition titer increase. Flow cytometry analysis revealed the increased Toll-like receptor 5 (TLR5) expression after EGCG3"Me treatment in lamina propria dendritic cells (LPDCs) and macrophages, which play crucial roles in the humoral immune system. TLR5 expression correlated with the level of interleukin-6 (IL-6)/C-C chemokine type receptor 5, which are important mediators of the humoral immunity. Taken together, In vivo and ex vivo studies showed that EGCG3"Me potentiated the split-virus vaccine-elicited immune response accompanied with the upregulation of TLR5 in intestine and splenocyte macrophages.

The combined effect of green tea and α-glucosyl hesperidin in preventing obesity: a randomized placebo-controlled clinical trial.

Green tea, a widely consumed beverage in Asia, contains green tea catechins effective against obesity, especially epigallocatechin-3-O-gallate (EGCG), but must be consumed in an impractically huge amount daily to elicit its biological effect. Meanwhile, citrus polyphenols have various physiological effects that could enhance EGCG functionality. Here we investigated the antiobesity effect of a combination of EGCG and α-glucosyl hesperidin, a citrus polyphenol, at doses that have not been previously reported to exert antiobesity effects by themselves in any clinical trial. In a randomized, placebo-controlled, double-blinded, and parallel-group-designed clinical trial, 60 healthy Japanese males and females aged 30-75 years consumed green tea combined with α-glucosyl hesperidin (GT-gH), which contained 178 mg α-glucosyl hesperidin and 146 mg EGCG, for 12 weeks. Physical, hematological, blood biochemical, and urine examinations showed that GT-gH is safe to use. At week 12, GT-gH prevented weight gain and reduced body mass index (BMI) compared with the placebo. Especially in those aged < 50 years, triglyceride and body fat percentage decreased at week 6, visceral fat level and body fat percentage decreased at week 12; body weight, BMI, and blood LDL/HDL ratio also decreased. In conclusion, taking GT-gH prevents weight gain, and the antiobesity effect of GT-gH was more pronounced in people aged < 50 years.

Glucosyl-hesperidin enhances the cyclic guanosine monophosphate-inducing effect of a green tea polyphenol EGCG.

Animal and clinical studies have revealed that (-)-epigallocatechin-3-O-gallate (EGCG), one of the major bioactive polyphenols in green tea, showed several pharmacological effects including anti-obesity effect and anti-inflammatory effect. We previously reported that the second messenger cyclic guanosine monophosphate (cGMP) mediates its anti-inflammatory and anti-cancer properties. Here we demonstrated that glucosyl-hesperidin, enhances the cGMP-inducing effects of green tea extract in vivo. Moreover, glucosyl-hesperidin intake potentiated the green tea-elicited upregulation of the anti-inflammatory factor, toll-interacting protein.

Eriodictyol-Amplified 67-kDa Laminin Receptor Signaling Potentiates the Antiallergic Effect of O-Methylated Catechin.

(-)-Epigallocatechin-3-O-(3-O-methyl) gallate (1, EGCG3″Me), an antiallergic O-methylated catechin, is present in high quantities in the green tea cultivar "Benifuuki" (Camellia sinensis L.). Previous studies have shown that EGCG3″Me inhibited basophil degranulation mediated through the cell-surface 67-kDa laminin receptor (67LR), but the mechanisms are not fully elucidated. This study aimed to investigate the mechanisms underlying the inhibitory effect of EGCG3″Me on IgE/antigen (Ag)-mediated degranulation and the combined effect of EGCG3″Me with eriodictyol (2), a bioactive flavanone. EGCG3″Me inhibited ß-hexosaminidase release from the rat basophilic/mast cell line RBL-2H3 stimulated by IgE/Ag and induced acid sphingomyelinase (ASM) activity. This induction was inhibited by anti-67LR antibody treatment. The ASM-specific inhibitor desipramine inhibited EGCG3″Me-induced suppression of degranulation. The soluble guanylate cyclase (sGC) inhibitor NS2028 weakened the potency of EGCG3″Me, and the sGC activator BAY41-2272 suppressed degranulation. The ability of EGCG3″Me to induce ASM activity and inhibit degranulation was amplified by eriodictyol. Furthermore, oral administration of the lemon-peel-derived eriodyctiol-7-O-glucoside (3) potentiated the suppressive effect of EGCG3″Me-rich "Benifuuki" green tea on the IgE/Ag-induced passive cutaneous anaphylaxis (PCA) reaction in BALB/c mice. These results suggest that EGCG3″Me inhibits IgE/Ag-mediated degranulation by inducing the 67LR/sGC/ASM signaling pathway, and eriodictyol amplifies this signaling.

Plasma Homocysteine Concentration is Associated with the Expression Level of Folate Receptor 3.

Folic acid and folate receptors (FOLRs) play an important role in the downregulation of homocysteine (Hcy), a risk factor of Alzheimer's disease, thrombosis, neuropsychiatric illness and fractures. While several studies have reported that FOLR1 and FOLR2 import folic acid into cells, the role of FOLR3 remains unknown. In this study, we evaluated the impact of FOLR3 on the metabolism of Hcy alongside its protective effect against homocysteine-induced neurotoxicity. To reveal the role of FOLR3, we constructed FOLR3-overexpressed HEK293 cells (FOLR3+ cells) and evaluated cell growth, folic acid intake and Hcy-induced neurotoxicity. Subjects with a high expression of FOLR3 exhibited low levels of plasma homocysteine. The ectopic expression of FOLR3 enhanced cell growth, and the enhanced effect was neutralised by folic acid-deficient media. The Western blot analysis revealed that FOLR3 is secreted into cell supernatant. The folic acid intake of FOLR3+ cells was higher than that of wild-type cells. Supernatant from FOLR3+ cells showed a protective effect on Hcy-induced cytotoxicity. FOLR3 expression in plasma is negatively correlated with plasma homocysteine. Our study emphasizes the role of FOLR3 in the intake of folic acid into cells on the one hand and its protective role in Hcy-induced cytotoxicity on the other.

EGCG down-regulates MuRF1 expression through 67-kDa laminin receptor and the receptor signaling is amplified by eriodictyol.

(-)-epigallocatechin-3-O-gallate (EGCG) is a bioactive polyphenol in green tea. Previous studies have demonstrated the beneficial effects of EGCG on muscle mass and muscle atrophy. In the current study, we investigated the mechanisms underlying effect of EGCG on muscle atrophy. It was demonstrated that EGCG suppressed muscle-specific ubiquitin ligase, muscle RING Finger 1 (MuRF1) expression through 67-kDa laminin receptor (67LR). Previous studies have shown that eriodictyol potentiates the anti-tumor activities of EGCG by amplifying 67LR signaling. Therefore, we investigated the effects of EGCG and eriodictyol on the MuRF1 expression in C2C12 myotubes. The combined treatment of EGCG and eriodictyol significantly suppressed MuRF1 expression in dexamethasone-treated C2C12 myotubes. Tail suspension was maintained for 10 consecutive days using C57BL6/J mice, and during this time EGCG and eriodictyol were orally administered. In the gastrocnemius muscle, the muscle mass loss was inhibited by the combination of EGCG and eriodictyol. Therefore, EGCG may prevent muscle atrophy by inducing 67LR signaling and eriodictyol amplifies this pathway.

Diallyl disulfide potentiates anti-obesity effect of green tea in high-fat/high-sucrose diet-induced obesity.

Obesity is a major problem in developed countries and a burden on social health care systems. Several epidemiological studies showed the protective effects of green tea against obesity-related diseases. Cyclic guanosine monophosphate (cGMP) acts as a mediator for the physiological effects of (-)-epigallocatechin-3-O-gallate, the major constituent of green tea. Here, we showed that the level of phosphodiesterase 5, a negative regulator of cGMP, was up-regulated in adipose tissues of high-fat/high-sucrose (HF/HS) diet-fed mice and that this up-regulation was ameliorated by diallyl disulfide (DADS), the major organosulfur in garlic. A green tea extract (GT) and DADS in combination attenuated HF/HS diet-induced adipose increase and triglyceride accumulation in the liver. In these mechanisms, the combination regimen suppressed the HF/HS diet-induced up-regulation of fatty acid synthesis-related enzymes including sterol regulatory element-binding protein-1 (SREBP-1), fatty acid synthase, and stearoyl-CoA desaturase-1. Moreover, this combination diet up-regulated thermogenesis-related genes including peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1 alpha and uncoupling proteins in both white and brown adipose tissues. In conclusion, we identified DADS as an enhancer of the anti-obesity effect of GT accompanied by the suppression of SREBP-1 and activation of PPAR axis. The combination diet is a novel and easily applicable approach against obesity-related diseases.

Postprandial glycaemia-lowering effect of a green tea cultivar Sunrouge and cultivar-specific metabolic profiling for determining bioactivity-related ingredients.

Although the major green tea catechins can inhibit the activity of carbohydrate-hydrolyzing enzymes, there is a paucity of information describing the potential of other green tea ingredients and numerous green tea cultivars. Herein, we reveled that a green tea cultivar Sunrouge significantly suppressed the postprandial blood glucose level in mice. Unlike the most representative Japanese green tea cultivar, Yabukita, the suppression by Sunrouge was observed clearly during the initial period after oral dosing of starch. Sunrouge also strongly inhibited the carbohydrate-hydrolyzing enzymes α-glucosidase and α-amylase when compared with that of Yabukita and many other cultivars. Liquid chromatography-mass spectrometry (LC-MS)-based metabolic profiling (MP) of 42 Japanese green tea cultivars was performed. Multivariate statistical analysis enabled visualization of the differences among cultivars with respect to their ability to inhibit carbohydrate-hydrolyzing activities. Analysis of metabolites, contributing to the discrimination and prediction of the bioactivity of cultivars, showed that O-methylated catechins, epicatechin-3-O-(3-O-methyl) gallate (ECG3"Me) and epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3"Me), were newly identified α-glucosidase inhibitors. Such ability was also observed in epigallocatechin-3-O-gallate (EGCG), epicatechin-3-O-gallate (ECG), delphinidin-3-O-glucoside and myricetin-3-O-glucoside. The amounts of these compounds in Sunrouge were higher than that in many other cultivars. These results suggest that Sunrouge has high potential for suppressing the elevation of the postprandial blood glucose level, and an MP approach may become a valuable strategy for evaluating the anti-hyperglycemic activity of green tea and for screening its active ingredients.

A Phytochemical-Sensing Strategy Based on Mass Spectrometry Imaging and Metabolic Profiling for Understanding the Functionality of the Medicinal Herb Green Tea.

Low-molecular-weight phytochemicals have health benefits and reduce the risk of diseases, but the mechanisms underlying their activities have remained elusive because of the lack of a methodology that can easily visualize the exact behavior of such small molecules. Recently, we developed an in situ label-free imaging technique, called mass spectrometry imaging, for visualizing spatially-resolved biotransformations based on simultaneous mapping of the major bioactive green tea polyphenol and its phase II metabolites. In addition, we established a mass spectrometry-based metabolic profiling technique capable of evaluating the bioactivities of diverse green tea extracts, which contain multiple phytochemicals, by focusing on their compositional balances. This methodology allowed us to simultaneously evaluate the relative contributions of the multiple compounds present in a multicomponent system to its bioactivity. This review highlights small molecule-sensing techniques for visualizing the complex behaviors of herbal components and linking such information to an enhanced understanding of the functionalities of multicomponent medicinal herbs.

Oligomer formation of a tea polyphenol, EGCG, on its sensing molecule 67 kDa laminin receptor.

Green tea polyphenol (-)-epigallocatechin-3-O-gallate (EGCG) has been attributed to the activation of its cell surface sensing receptor 67 kDa laminin receptor (67LR). However, the action of EGCG to activate 67LR remains unknown. Here we show that EGCG undergoes oligomer formation on its surface receptor 67LR.

Identification of 3-methylbutanoyl glycosides in green Coffea arabica beans as causative determinants for the quality of coffee flavors.

The quality of coffee green beans is generally evaluated by the sensory cupping test, rather than by chemical compound-based criteria. In this study, we examined the relationship between metabolites and cupping scores for 36 varieties of beans, using a nontargeted LC-MS-based metabolic profiling technique. The cupping score was precisely predicted with the metabolic information measured using LC-MS. Two markers that strongly correlated with high cupping scores were determined to be isomers of 3-methylbutanoyl disaccharides (3MDs; 0.01-0.035 g/kg of beans) by spectroscopic analyses after purification, and one of them was a novel structure. Further, both the 3MDs were determined to be precursors of 3-methylbutanoic acid that enhance the quality of coffee. The applicability of 3MDs as universal quality indicators was validated with another sample set. It was concluded that 3MDs are the causative metabolites determining beverage quality and can be utilized for green bean selection and as key compounds for improving the beverage quality.

Metabolic profiling-based data-mining for an effective chemical combination to induce apoptosis of cancer cells.

Green tea extract (GTE) induces apoptosis of cancer cells without adversely affecting normal cells. Several clinical trials reported that GTE was well tolerated and had potential anti-cancer efficacy. Epigallocatechin-3-O-gallate (EGCG) is the primary compound responsible for the anti-cancer effect of GTE; however, the effect of EGCG alone is limited. To identify GTE compounds capable of potentiating EGCG bioactivity, we performed metabolic profiling of 43 green tea cultivar panels by liquid chromatography-mass spectrometry (LC-MS). Here, we revealed the polyphenol eriodictyol significantly potentiated apoptosis induction by EGCG in vitro and in a mouse tumour model by amplifying EGCG-induced activation of the 67-kDa laminin receptor (67LR)/protein kinase B/endothelial nitric oxide synthase/protein kinase C delta/acid sphingomyelinase signalling pathway. Our results show that metabolic profiling is an effective chemical-mining approach for identifying botanical drugs with therapeutic potential against multiple myeloma. Metabolic profiling-based data mining could be an efficient strategy for screening additional bioactive compounds and identifying effective chemical combinations.

Small molecule-sensing strategy and techniques for understanding the functionality of green tea.

Various low-molecular-weight phytochemicals in green tea (Camellia sinensis L.), especially (-)-epigallocatechin-3-O-gallate (EGCG), are known to be involved in health promotion and disease risk reduction. However, the underlying mechanism has remained elusive because of the absence of an analytical technique that can easily detect the precise behavior of such a small molecule. Recently, we have identified a cell-surface EGCG-sensing receptor and the related signaling molecules that control the physiological functions of EGCG. We also developed a novel in situ label-free imaging technique for visualizing spatially resolved biotransformations based on simultaneous mapping of EGCG and its phase II metabolites. Furthermore, we established a chemometric method capable of evaluating the functionality of multicomponent green tea extracts by focusing on their compositional balances. This review highlights our proposed small molecule-sensing techniques for detecting the complex behavior of green tea components and linking such information to an enhanced understanding of green tea functionality.

In situ label-free visualization of orally dosed strictinin within mouse kidney by MALDI-MS imaging.

Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a powerful technique for visualizing the distribution of a wide range of biomolecules within tissue sections. However, methodology for visualizing a bioactive ellagitannin has not yet been established. This paper presents a novel in situ label-free MALDI-MSI technique for visualizing the distribution of strictinin, a bioactive ellagitannin found in green tea, within mammalian kidney after oral dosing. Among nine representative matrix candidates, 1,5-diaminonaphthalene (1,5-DAN), harmane, and ferulic acid showed higher sensitivity to strictinin spotted onto a MALDI sample plate. Of these, 1,5-DAN enables visualization of a two-dimensional image of strictinin directly spotted on mouse kidney sections with the highest sensitivity. Furthermore, 1,5-DAN-based MALDI-MSI could detect the unique distribution of orally dosed strictinin within kidney sections. This in situ label-free imaging technique will contribute to the localization analysis of strictinin and its biological mechanisms.