Japanese Green Tea Research Articles

Chromosome-Scale Genome Assembly and Characterization of Top-Quality Japanese Green Tea Cultivar 'Seimei'.

Japanese green tea, an essential beverage in Japanese culture, is characterized by the initial steaming of freshly harvested leaves during production. This process efficiently inactivates endogenous enzymes such as polyphenol oxidases, resulting in the production of sencha, gyokuro and matcha that preserves the vibrant green color of young leaves. Although genome sequences of several tea cultivars and germplasms have been published, no reference genome sequences are available for Japanese green tea cultivars. Here, we constructed a reference genome sequence of the cultivar 'Seimei', which is used to produce high-quality Japanese green tea. Using the PacBio HiFi and Hi-C technologies for chromosome-scale genome assembly, we obtained 15 chromosome sequences with a total genome size of 3.1 Gb and an N50 of 214.9 Mb. By analyzing the genomic diversity of 23 Japanese tea cultivars and lines, including the leading green tea cultivars 'Yabukita' and 'Saemidori', it was revealed that several candidate genes could be related to the characteristics of Japanese green tea. The reference genome of 'Seimei' and information on genomic diversity of Japanese green tea cultivars should provide crucial information for effective breeding of such cultivars in the future.

일본산 품종 녹차의 우림 조건과 품종별 주요 성분

The flavors of tea vary depending on various factors, among which the taste of tea is greatly determined by the elution rate of each component contained in tea leaves. This study analyzed the infusion characteristics of Japanese green tea such as ‘Yabukita’, ‘Fusun’, ‘Okumidori’, and ‘Benifuki’. The brewing water temperature was 20, 40, 60, 80, or 100°C, and the brewing time consisted of one and two minutes. The elution rate of amino acids increased from 22.7-76.6% and 4.0-81.8% in theanine as the brewing water temperature and time were increased. The elution rates for polyphenols, catechins, and caffeine were 4.5-74.8%, 4.9-70.4%n, and 3.5-80.1%, respectively. The result indicated that the elution of components increased as brewing water temperature and time increased from 20 to 100°C and from one to two minutes, respectively. Amino acids were eluted at a slightly higher rate even at low temperatures, whereas polyphenols, and catechins were well eluted at temperatures above 80°C. These results suggest that each component related to the taste of tea has different elution characteristics. In addition, the elution conditions can be adjusted to achieve the favorite taste of tea.

Effect of shading on trichome formation and CAPRICE-like gene expression in tea (Camellia sinensis var. sinensis) leaves

Tea (Camellia sinensis var. sinensis) is one of the most popular beverages worldwide and is highly regarded for its unique taste and health benefits. The traditional practice of shading tea plants before harvest is employed to ensure the production of high-quality Japanese green tea. However, the precise effects of shading on trichome formation, leaf tissue structure, and the expression of related genes remain largely unknown. In the present study, we conducted a comparative analysis to investigate the effect of shading on the aforementioned aspects of tea leaves. Our findings revealed a significant decrease in the number of trichomes in the youngest 1st stage leaves under shaded conditions compared with that under full-light conditions. Histological analyses revealed that epidermal cells in tea leaves under shaded conditions were thinner, further indicating the influence of light on leaf structures. To delve deeper into the regulatory mechanisms, the expression levels of six Camellia sinensis CAPRICE (CsCPC) genes encoding R3 MYB transcription factors, which have been implicated in trichome formation in tea plants, were examined using real-time reverse transcription PCR. Among the six genes, CsCPC-1, Camellia sinensis ENHANCER OF TRY AND CPC 1–2 (CsETC1–2), and CsETC3 exhibited increased expression under shaded conditions, indicating their potential involvement in the light-mediated regulation of tea leaf characteristics. The expression levels of the phenylpropanoid pathway structural genes Camellia sinensis cinnamic acid 4-hydroxylase (CsC4H), Camellia sinensis cinnamoyl CoA reductase (CsCCR), and Camellia sinensis flavanone 3′ hydroxylase (CsF3′H), were significantly reduced under shaded conditions, suggesting the regulation of phenylpropanoid content. Our study demonstrated that shading treatment induces significant changes in the number of trichomes in younger leaves, alters the width of epidermal cells, and affects the expression levels of CsCPCs and genes related to the phenylpropanoid pathway. These findings have the potential to enhance tea leaf quality, and offer pragmatic implications for tea farming.

Balancing the environment and customer value: evaluation of the attractiveness of label-free plastic bottles for green tea

PurposeAs a measure against plastic waste, Coca-Cola and Evian have begun introducing label-free plastic bottles. Food labels have long been recognized as an important marketing tool, but there is a lack of research on label-free products. To address this gap, this study examined the influence of label-free design on product attractiveness in the Japanese green tea market.Design/methodology/approachIf existing products are used in an experiment, respondents would be subject to brand image bias. Hence, by mechanically combining the main design elements (cap shape, bottle style, decoration line, logo and label) with an orthogonal array, the conditions for bottles with and without labels are completely aligned. The authors conducted an online survey and applied the chi-square test to the attractiveness of 18 designs presented in random order.FindingsLabel-free designs were more attractive to consumers than labeled designs. The effect was higher among female, middle-aged and older adults; those with higher annual income and low-frequency purchasers.Practical implicationsPractitioners should adopt a label-free design that can satisfy both environmental considerations and customer value. It would be a formidable challenge to change the longstanding emphasis placed on label design, but this study demonstrates the value of doing so.Originality/valueThis is the first study in the package design literature on the advantages of label-free plastic bottles. The authors also applied an orthogonal array used for many years to optimize objective numerical values in marketing research.

Fecal fermentation and gut microbiota modulation of dietary fibre and polyphenols from Gnetum gnemon Linn. leaves

The purpose of this study was to analyze the effects of Gnetum gnemon var.tenerum leaf powder, dried using a vacuum microwave, on gut health properties. The two alternative drying conditions were 3600 Watts for 12 min (G1) and 2400 Watts for 15 min (G2) compared to the commercial Japanese green tea matcha powder (M) and the gut health effects were assessed by human fecal fermentation in a one-stage colon system. The enumeration of gut microbiota at 24 h of fermentation by next generation sequencing (NGS) confirmed elevated Bacteroides levels and significantly (P < 0.05) higher numbers of Bifidobacterium with G1 (33%) and G2 (37%) compared to M (31%). Additionally, short-chain fatty acid (SCFA) profile for acetic, propionic and butyric acids was analysed using gas chromatography-flame ionization detector (GC-FID), and especially butyric acids was significantly (P < 0.05) higher with G1 (4.698 ± 0.61 mM) and G2 (2.768 ± 0.10 mM) compared to M, 1.805 ± 0.01 mM at 24 h. The Gnetum leaf powders G1 and G2 were investigated for promoting γ-aminobutyric acid (GABA) microbial metabolite, which was detected using liquid chromatography-mass/mass spectrometry (LC-MS/MS). Thus, Gnetum gnemon var. tenerum leaf powder could provide gut health benefits with good potential for use as a functional food ingredient in the future.

Discrimination of Sayamakaori and Yabukita Which Are Original Plant Source of Japanese Green Tea and Identification of Specific Compounds for the Former by Nuclear Magnetic Resonance Metabolomics Techniques Combined with Isolation by Chromatography Methods

Camellia sinensis leaves are one of the most economically important crops, and various tea cultivars are available in Japan. In the present study, we compared the constituents of Camellia sinensis var. sinensis cv. Yabukita (“Yabukita”), a standard tea cultivar, and those of C. sinensis var. sinensis cv. Sayamakaori (“Sayamakaori”), grown in Saitama Prefecture, using proton nuclear magnetic resonance (1H-NMR) metabolomics technology. Principal component analysis and hierarchical cluster analysis of 1H-NMR spectroscopic data of the MeOH extracts of C. sinensis leaves revealed differences in the metabolic profiles of each tea cultivar. Chromatographic separation based on 1H-NMR spectral data showed that kaempferol 3- O-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside was a distinct component of “Sayamakaori”. This compound can be used as maker for the identification of “Sayamakaori” and the maintenance of its quality.

Antimicrobial Efficiency of Different forms of Tea Extract (Camellia sinensis) against Cariogenic Pathogens

Introduction: Dental caries is a frequent chronic infectious condition in the general population. Streptococcus mutans and Lactobacillus acidophilus play a significant part in the cause of dental caries. Various antimicrobials have been tried to prevent these microorganisms. Traditional herbal medicine extracted from plants has been employed as a remedy. Among them, tea leaf extract showed promising antimicrobial properties against infections. Aims: The current study was designed to assess the antibacterial activity of various types of tea extract against cariogenic microorganisms. Methods: S. mutans and L. acidophilus were grown in this in-vitro experimental study and maintained in their respective agars. Three different concentrations of 250 mg/ml aqueous, 250 mg/ml ethanolic, and 250 mg/ml aqueous with sugar solutions were prepared from Japanese green tea, Oolong Chinese tea, and Sabah black tea. Kirby-Bauer disc diffusion method was used to assess the antibacterial activity of tea extracts. As positive and negative control groups, 0.2% chlorhexidine and 1% DMSO were employed. The zone of inhibition was determined in millimetres following a 24-hour incubation period at 37 °C. Results: Japanese green tea at its three different concentrations exhibited significantly higher mean zones of inhibition of 18.33 mm, 27.70 mm, and 18.96 mm, respectively, against S. mutans at p&lt;0.001 compared to L. acidophilus. In contrast, chlorhexidine showed 27.53 mm and 19.39 mm for S. mutans and L. acidophilus, respectively. Conclusion: Japanese green tea demonstrated superior antibacterial activity at its ethanolic concentration compared to other concentrations and the other two types of tea.

MP03-17 L-γ-GLUTAMYLETHYLAMIDE PREVENTS LOWER URINARY TRACT DYSFUNCTION INDUCED BY CHRONIC SYMPATHETIC HYPERACTIVITY

You have accessJournal of UrologyCME1 Apr 2023MP03-17 L-γ-GLUTAMYLETHYLAMIDE PREVENTS LOWER URINARY TRACT DYSFUNCTION INDUCED BY CHRONIC SYMPATHETIC HYPERACTIVITY Kanako Matsuoka, Kei Yaginuma, Yu Endo, Yuki Harigane, Yuta Matsuoka, Yuki Yoshida, Hitomi Imai, Akifumi Onagi, Seiji Hoshi, Tomoyuki Koguchi, Junya Hata, Yuichi Sato, Hidenori Akaihata, Masao Kataoka, and Yoshiyuki Kojima Kanako MatsuokaKanako Matsuoka More articles by this author , Kei YaginumaKei Yaginuma More articles by this author , Yu EndoYu Endo More articles by this author , Yuki HariganeYuki Harigane More articles by this author , Yuta MatsuokaYuta Matsuoka More articles by this author , Yuki YoshidaYuki Yoshida More articles by this author , Hitomi ImaiHitomi Imai More articles by this author , Akifumi OnagiAkifumi Onagi More articles by this author , Seiji HoshiSeiji Hoshi More articles by this author , Tomoyuki KoguchiTomoyuki Koguchi More articles by this author , Junya HataJunya Hata More articles by this author , Yuichi SatoYuichi Sato More articles by this author , Hidenori AkaihataHidenori Akaihata More articles by this author , Masao KataokaMasao Kataoka More articles by this author , and Yoshiyuki KojimaYoshiyuki Kojima More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003214.17AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Chronic sympathetic hyperactivity had been reported as a factor of lower urinary tract dysfunction (LUTD), but little is known about the mechanisms. L-γ-glutamylethylamide (L-theanine), one of the glutamine derivatives in Japanese green tea, has recently focused on the sympathetic inhibitory effects. Hence, we speculated that L-theanine might suppress the development of LUTD associated with chronic sympathetic hyperactivity. This study aimed to clarify the mechanisms underlying the effect of L-theanine on LUTD in spontaneously hypertensive rats (SHR) known as one of OAB rat models with chronic sympathetic hyperactivity. METHODS: Twelve-week-old SHR were divided into two groups (controls, n=10; L-theanine, n=10). The L-theanine group was given only L-theanine solution to drink freely. After six weeks, blood pressure, plasma catecholamine level measurement, and cystometry were performed in both groups. The bladder tissue was harvested for pharmacological studies, histological examinations, and protein expression analysis. Contractile responses to 80-mM KCl, electrical field stimulation, 1-mM ATP, and carbachol in organ baths were recorded. Malondialdehyde (MDA), biomarkers for oxidative stress, was assessed using immunohistochemical staining and Western blotting. Values of p<0.05 were considered statistically significant. RESULTS: There was no significant difference in systolic and diastolic blood pressure between two groups. Mean blood pressure was significantly lower in the L-theanine group than in controls (p=0.046). The plasma noradrenaline level was significantly lower in the L-theanine group (365.5±31.6 pg/ml) than in controls (246.2±34.3 pg/ml, p=0.04). The cystometrogram showed the micturition interval and mean voided volume were significantly larger in the L-theanine group (7.8±1.7 min, 1.3±0.35 ml) than in controls (5.6±8.4 min, 0.96±0.18 ml, p=0.002, p=0.03). Contractile responses of bladder strip were significantly higher in the L-theanine group than in controls. The collagen/muscle ratio of the bladder smooth muscle was significantly decreased in the L-theanine group (p=0.02). The expression of MDA was significantly decreased in the L-theanine group (p<0.001). CONCLUSIONS: These results suggested that L-theanine ameliorated excessive contraction of vascular smooth muscle in peripheral small arteries by suppressing elevated serum levels of noradrenaline in SHR, thereby decreasing MBP. Oral administration of L-theanine for 6 weeks may contribute to the prevention of bladder voiding function, along with storage function by increasing blood perfusion in the bladder. Source of Funding: Nothing © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e30 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kanako Matsuoka More articles by this author Kei Yaginuma More articles by this author Yu Endo More articles by this author Yuki Harigane More articles by this author Yuta Matsuoka More articles by this author Yuki Yoshida More articles by this author Hitomi Imai More articles by this author Akifumi Onagi More articles by this author Seiji Hoshi More articles by this author Tomoyuki Koguchi More articles by this author Junya Hata More articles by this author Yuichi Sato More articles by this author Hidenori Akaihata More articles by this author Masao Kataoka More articles by this author Yoshiyuki Kojima More articles by this author Expand All Advertisement PDF downloadLoading ...

Green with Milk and Sugar: When Japan Filled America's Tea Cups

Narrating the history of Japanese green tea, once commonly consumed by Americans with “milk and sugar,” Robert Hellyer masterfully describes processes of transnational mercantile exchange spanning the nineteenth and twentieth centuries, where East Asian and Anglo-American capitalistic practices neatly intersected. Green with Milk and Sugar shines with vivid descriptions of individual American and Japanese merchants heavily invested in commerce and buffeted by vicissitudes in US-Japan relations during a volatile century of interactions. Illuminating photographs, descriptive advertisements, and product labels paint a striking picture of the brokers and marketing practices for Japanese green tea. Hellyer found inspiration in his great-great-grandfather Frederick, who profited from Chicago's centrality in the 1880s tea trade. Creating a US market for green tea mobilized transpacific and transatlantic networks of tea dealers, transporters, and producers; the text thus employs a “commodity chain” approach to “illuminate the intertwined domestic and international story of how Japanese green tea became so prevalent in American cups” from the nineteenth century until the 1940s, when World War II interrupted supply chains and rendered Japanese commodities unpatriotic (4).Hellyer's book echoes the global contexts of recent commodity histories, simultaneously showing how the American Midwest became “the center of Japanese green tea consumption” as lower prices helped “democratize” the commodity and how increased agricultural production of exportable green tea influenced Japanese consumer tastes that now associate sencha (a loose-leaf form of green tea) with Japanese national identity.Around 1870, Japanese diplomatic officials noted a puzzling fad—Americans expected color-enhanced tea. A new, US-centric commodity arose in Nagasaki, where Chinese experts prepared Japanese green tea on an industrial scale to suit American tastes by pan-firing leaves and adding Prussian Blue coloring in a Sino-Japanese coproduction catering to American consumer aesthetics. New York tea retailers then marketed the “Japan Tea” brand. Chicago, a commercial hub with rail networks reaching both coasts, fashioned the Midwest into “America's definite ‘green tea country’ . . . a place where green tea became ‘democratized,’ within the reach of all social classes” (92).Hellyer intriguingly claims that “the making of Japan Tea into a successful brand on the US market provides one explanation for how a diffuse political polity . . . emerged to become a more unified Japanese nation” (89). He argues that the “Japan-US commodity chain . . . brought fresh employment opportunities and thus avenues for personal reinvention across Japanese society, helping salve the socioeconomic and political wounds of the war and the dislocations brought by Meiji government reforms” (54). The city of Sunpu, later known as Shizuoka, featured intensive tea cultivation by former samurai elites, who lost status amid the new Meiji regime's reforms but now gained a source of wealth. Local wealthy elites provided capital for local tea farms, preventing the growth of large-scale monopolies in tea production and allowing a strong, regional process of capital accumulation. In 1874, Japan's government extended bureaucratic support to expand tea globally; the Ministry of Home Affairs created an Industrial Promotion Bureau with a Tea Office to diversify tea exports, including black tea.Darker factors emerged to threaten Japanese tea's global expansion as Anglo-American rivalries grew in tea industries. Since the late nineteenth century, US newspaper advertisements had proliferated racist imagery of “dirty” East Asian “coolies,” with British tea plantations in India and Ceylon marketing wares emphasizing white superiority, like the Monsoon brand, produced by “civilized labor and intelligence,” and the Blue Cross brand, “carefully prepared under white supervision—[while] China and Japan teas are not” (126–27). Racialized discourse in advertisements attempted to dissuade white American middle-class consumers from consuming green tea and to switch to “civilized” black tea. By the 1920s, Japanese tea suffered multiple setbacks in the US market, including perceptions of a lower-quality product, while South Asian black teas made inroads with lobbies promoting cheaper India and Ceylon black teas. Its near death knell arrived with imperial Japan's 1941 attack on the United States and its colonies.Deeper analyses of fraught American relationships with East Asian immigrant groups, especially laborers from China and Japan, would have been welcome, along with descriptions emphasizing social class for Japanese immigrants, who initially worked in agricultural professions or gardening and later developed small businesses, including groceries importing tea. However, Green with Milk and Sugar is a well-researched, immensely captivating story of a now commonplace Japanese commodity with deep historical roots enthusiastically rediscovered by Americans. Over a roughly century-long transnational history, Hellyer concludes that the emergence of new sencha tea production and consumption patterns in Japan was “intimately connected to major developments both within Japan and in the American market” (198).

Sichuan dark tea improves lipid metabolism and prevents aortic lipid deposition in diet-induced atherosclerosis model rats.

Sichuan dark tea (ST), Zangcha, is a traditional fermented Chinese tea found in Sichuan and Tibet and claimed for beneficial effects against lifestyle-related metabolic disorders. We examined the effects of ST on lipid metabolism and atherosclerosis. Sichuan dark tea was given to fat-rich diet-induced atherosclerosis model rats in comparison with dark-fermented Chinese Pu-erh tea (PT) and Japanese green tea (GT). After 8 weeks of feeding, ST and PT induced an increase in high-density lipoprotein (HDL)-cholesterol and a decrease in glucose, and ST decreased triglyceride in plasma. ST also induced low pH in the cecum. There was no significant change in their body weight among the fat-feeding groups but a decrease was found in the visceral fat and liver weight in the ST group. Accordingly, ST reduced lipid deposition in the aorta in comparison with PT and GT. ST increased mRNA of LXRα, PPARα, PPARγ, and ABCA1 in the rat liver. The extract of ST stimulated the AMPK pathway to increase the expression of ABCA1 in J774 cells and increased expression of lipoprotein lipase and hormone-sensitive lipase in 3T3L1 cells, consistent with its anti-atherogenic effects in rats. High-performance liquid chromatography analysis showed unique spectra of original specific compounds of caffeine and catechins in each tea extract, but none of them was likely responsible for these effects. Sichuan dark tea increases plasma HDL and reduces plasma triglyceride to decrease atherosclerosis through AMPK activation. Further study is required to identify specific components for the effects of this tea preparation.

Influence of manufacturing system scale for commercial Japanese green tea (Sencha) production on biochemical characteristics of tea leaf and infusion

AbstractDried green tea leaves (Sencha) were manufactured using various scale manufacturing systems, which processed batch‐wise for 15 kg (15 K), 60 kg (60 K), and 120 kg (120 K) fresh leaves. Total polyphenol content (TPC) and antioxidant activity (FRAP and DPPH) of dried tea leaves and infusions were evaluated. The values of TPC, FRAP, and DPPH of dried tea leaves processed by the larger systems (120 K and 60 K) were significantly higher than the values by the smaller system (15 K). In contrast, with the larger system scale, some of the leaves were not fully rolled and were not mechanically damaged during processing. These incomplete processing conditions led to the extraction of significantly fewer polyphenols in hot water, which might influence the health benefits of green tea infusions. This study indicated that there could be an optimal system scale that considers the balance between economic and health benefits, involving the optimization of production quality/amount.Practical ApplicationsAfter harvest, Japanese green tea leaves are gradually dried using batch‐wise processing systems. The processing system scale is permanently fixed by the size of one batch, which is selected according to the circumstances of the production area and demand for tea production. However, tea leaf producers have experientially been aware of the quality variations in the final tea products, depending on the system scale. In this study, the impact of the scale of the manufacturing system on the functional properties of green tea was investigated. The results revealed that the hot water extract of dried tea leaves processed by a larger system scale tended to have less functional properties than those by a smaller system. This was due to the comparatively incomplete rolling conditions of tea leaves processed by larger manufacturing systems. These differences influence the preservability and extractability of the chemical components of the green tea leaves. Our findings provide beneficial information regarding processing conditions for better functional green tea infusions.

Combustion characteristics of densified solid biofuel with different aspect ratios

Bio-coke is a solid biofuel with a high density and high compressive strength. Demonstration tests have shown that bio-coke can be used as an alternative to coal and coal coke. The effects of biomass type and production conditions on combustion characteristics have been studied for small diameter bio-coke (φ50 mm or less). In this study, we focused on fuel size and investigated the combustion characteristics of φ12 to 100 mm samples. Experiments were conducted in a preheated, forced convection atmosphere using a batch-type vertical combustion apparatus to simulate rapid temperature increase and combustion under isothermal conditions in a gasification and melting furnace or blast furnace. Two biomass species (Japanese cedar and green tea) were selected as materials to study the effect of biomass species. We developed experimental correlations to predict the combustion time of bio-coke, considering the effects of scale and aspect ratio. The flaming and char combustion times of bio-coke can be approximated using the shape factor (V/S)n even when the aspect ratios are different. We obtained that the characteristic length is (V/S) to the power of 0.52–0.64. Furthermore, we found that Japanese cedar bio-coke has 2.5 times faster in flaming combustion than green tea bio-coke.

Anti-SARS-CoV-2 activity of various PET-bottled Japanese green teas and tea compounds in vitro.

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a serious threat to global public health. The emergence of SARS-CoV-2 variants is a significant concern regarding the continued effectiveness of vaccines and antiviral therapeutics. Thus, natural products such as foods, drinks, and other compounds should be investigated for their potential to treat COVID-19. Here, we examined the in vitro antiviral activity against SARS-CoV-2 of various polyethylene terephthalate (PET)-bottled green Japanese teas and tea compounds. Six types of PET-bottled green tea were shown to inhibit SARS-CoV-2 at half-maximal inhibitory concentrations (IC50) of 121- to 323-fold dilution. Our study revealed for the first time that a variety of PET-bottled Japanese green tea drinks inhibit SARS-CoV-2 infection in a dilution-dependent manner. The tea compounds epigallocatechin gallate (EGCG) and epicatechin gallate showed virucidal activity against SARS-CoV-2, with IC50 values of 6.5 and 12.5 µM, respectively. The investigated teas and tea compounds inactivated SARS-CoV-2 in a dose-dependent manner, as demonstrated by the viral RNA levels and infectious titers. Furthermore, the green teas and EGCG showed significant inhibition at the entry and post-entry stages of the viral life cycle and inhibited the activity of the SARS-CoV-2 3CL-protease. These findings indicate that green tea drinks and tea compounds are potentially useful in prophylaxis and COVID-19 treatment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00705-022-05483-x.

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.

Optimizing the Quality and Commercial Value of Gyokuro-Styled Green Tea Grown in Australia

Gyokuro is a style of Japanese green tea produced by employing agricultural shading in the weeks before harvest. This method results in a tea product with different organoleptic and chemical properties than common Japanese green tea. In an effort to yield the highest quality and commercially valuable green tea product, the present study explores the influence of shading treatments and the duration of shading on the natural biochemistry of the green tea plant. This study applied shading treatments at light intensity conditions of 40%, 16%, 10% and 1% of available ambient light and the application of a red-colored shade cloth of 60% opacity. The Quality Index Tool was used to measure the quality and commercial value of the green tea, using individual target constituents (theanine, caffeine and the catechins) quantified from HPLC analysis. This study shows that very high levels of total visible spectrum light shading (~99%) is required to achieve improvements in quality and commercial value. Specifically, this improvement is a direct result of changes in the mood- modifying bioactive metabolites theanine and caffeine. This study concludes that in green tea growing regions with more hours of sunlight per year, such as on the Central Coast of Australia, more intense shading will achieve products with improved quality and commercial value, which has more potential to be marketed as a functional ingredient.

Changes in Morphological and Functional Characteristics of Tea Leaves During Japanese Green Tea (Sencha) Manufacturing Process

Changes in Morphological and Functional Characteristics of Tea Leaves During Japanese Green Tea (Sencha) Manufacturing Process

Evaluation of Roasting Effect on Selected Green Tea Volatile Flavor Compound and Pyrazine Content by HS-SPME GC-MS

The present study aims at the development and validation of a quali-quantitative headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME GC-MS) method for the analysis of odorants in different Chinese and Japanese green teas. A 65 µm PDMS/DVB fiber was used, and GC-MS was performed on a ZB-5 (30 m × 0.25 mm ID, 0.25 μm film) column. The main odorants in green tea samples were identified and the method was fully validated. Linearity (r2 0.981–0.999), sensitivity (LOQ 0.005–0.04 µg/mL), reproducibility (CV% 3.12–10.37), accuracy (recovery% 79.08–99.17) and matrix effect (ME% −9.5 to +4.5) were determined. Quantitation of 2,4-heptadienal, β-damascenone, β-ionone, linalool, indole, 2-ethyl-6-methyl-pyrazine, 2-ethyl-5-methyl-pyrazine, 2-ethyl-3,6-dimethylpirazine, 2-ethyl-3,5-dimethyl-pyrazine and 2-acetyl-pyrazine was carried out in the presence of isotopically labeled compounds as the internal standards. The proposed method was applied to the comparison of the profile of the volatile flavor compounds (VFCs) of green tea subjected to roasting treatment at three different temperatures (160, 180 and 200 °C for 30 min). In particular, the roasting process was monitored by following the quantitative variations of the selected odorant content, considered as the most important contributory components to the Hojicha or black tea (roasted tea) flavor. A temperature of 160 °C was found to be the best roasting temperature.

Green Tea Catechin, Epigallocatechin Gallate, Prevents Bone Loss in Hindlimb-Unloading Mice

Abstract Objectives Osteoporosis is a major health problem in the elderly characterized by bone loss and micro-architectural deterioration of bone tissue and associated with an increased risk of fracture. Prolonged bed rest, or physical inactivity during space flight causes rapid and marked bone loss. The effects of catechin, the main ingredient of Japanese green tea, on the bone are currently under study. It has been shown that green tea catechin modulates bone resorption in osteoclasts. However, there is no evidence supporting its inhibitory effect on bone loss during physical inactivity. In the present study, we investigated whether green tea catechin prevented bone loss through skeletal hindlimb-unloading in mice. Methods Female 8-week-old ddY mice were divided into five groups (n = 6–8 each) and subjected to: (1) normal housing fed a control diet, (2) sham unloading fed a control diet, (3) hind limb-unloading fed a control diet, (4) hind limb-unloading fed a 0.05% epigallocatechin gallate (EGCG)-containing diet, and (5) hind limb-unloading fed a 0.25% EGCG-containing diet for three weeks. Purified EGCG (97%) was used for green tea catechin. Results Bone mineral density of the tibia significantly decreased in hind limb-unloading mice. Treatment with 0.25% EGCG prevented bone loss and maintained trabecular bone mineral density more significantly than in cortical bones. The 0.25% EGCG diet inhibited decrease in the gene expression of alkaline phosphatase, a marker of bone formation, in the bone marrow in hind limb-unloading mice. Conclusions These results suggest that EGCG has ability to prevent bone loss induced by hindlimb-unloading in mice. These osteoprotective effects of EGCG may result from the inhibition of unloading-induced decrease in bone formation. Funding Sources This work was supported by the Honjo International Scholarship Foundation of Japan.

OS-PCA: Orthogonal Smoothed Principal Component Analysis Applied to Metabolome Data.

Principal component analysis (PCA) has been widely used in metabolomics. However, it is not always possible to detect phenotype-associated principal component (PC) scores. Previously, we proposed a smoothed PCA for samples acquired with a time course or rank order, but hypothesis testing to select significant metabolite candidates was not possible. Here, we modified the smoothed PCA as an orthogonal smoothed PCA (OS-PCA) so that statistical hypothesis testing in OS-PC loadings could be performed with the same PC projections provided by the smoothed PCA. Statistical hypothesis testing is especially useful in metabolomics because biological interpretations are made based on statistically significant metabolites. We applied the OS-PCA method to two real metabolome datasets, one for metabolic turnover analysis and the other for evaluating the taste of Japanese green tea. The OS-PCA successfully extracted similar PC scores as the smoothed PCA; these scores reflected the expected phenotypes. The significant metabolites that were selected using statistical hypothesis testing of OS-PC loading facilitated biological interpretations that were consistent with the results of our previous study. Our results suggest that OS-PCA combined with statistical hypothesis testing of OS-PC loading is a useful method for the analysis of metabolome data.

Identifying Factors for Expanding Japanese Green Tea Exports to the United States: From Changes in Demand Structure in the United States

Identifying Factors for Expanding Japanese Green Tea Exports to the United States: From Changes in Demand Structure in the United States