Green Tea Research Articles

GC-MS Combined with Proteomic Analysis of Volatile Compounds and Formation Mechanisms in Green Teas with Different Aroma Types.

Aroma is one of the key factors for evaluating the quality of green tea. A tender aroma (NX) and floral-like aroma (HX) are two types of high-quality aroma of green tea. In this work, the different aroma types of baked green tea were classified by sensory evaluation. Then, seven tea samples with a typical tender or floral-like aroma were selected for further volatile component analysis by GC-MS. A total of 43 aroma compounds were identified in two different aroma types of baked green tea samples. The PCA showed that linalool, geraniol, 3-hexenyl butyrate, and 3-hexenyl hexanoate were the major volatiles contributing to the HX. On the other hand, most of the alcohol volatiles, such as 1-octanol, 1-octen-3-ol, 1-dodecanol, 1-hexadecanol, phenylethyl alcohol, benzyl alcohol, aldehydes and some hydrocarbons contributed more to the NX. In addition, the chemical composition analysis showed that the content of free amino acids was higher in NX green tea samples, while the content of catechins was relatively higher in HX tea samples. A proteomic analysis revealed that most of the enzymes involved in VPBs pathways, such as phenylalanine ammonialyase, peroxidase, and shikimate-O-hydroxycinnamoyl transferase, were more abundant in NX than in HX tea samples. These results laid a foundation for the aroma formation mechanism of different aroma types of baked green tea and provided some theoretical guidance for the breeding of specific aroma varieties.

The physiological levels of epigallocatechin gallate (EGCG) enhance the Cd-induced oxidative stress and apoptosis in CHO-K1 cells

Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a significant threat to human health and life. It is therefore important to find an effective way of protecting organisms from their adverse effects. One potential product showing a protective effect is green tea. It has been shown that EGCG, which is found in large amounts in green tea, has strong antioxidant properties and can therefore protect cells from the adverse effects of heavy metals. Therefore, the aim of the study was to investigate the effect of EGCG on cells exposed to Cd. In the study, CHO-K1 cells (Chinese hamster ovary cell line) were treated for 24 h with Cd (5 and 10 µM) and EGCG (0.5 and 1 µM) together or separately. Cell viability, ATP content, total ROS activity, mitochondrial membrane potential and apoptosis potential were determined. The results showed that, in tested concentrations, EGCG enhanced the negative effect of Cd. Further analyses are needed to determine the exact mechanism of action of EGCG due to the small number of publications on the subject and the differences in the results obtained in the research.

Effect of Hydroalcoholic Extract of Chamomile, Aloe Vera, and Green Tea on the Diabetic Wound in Rats

Effect of Hydroalcoholic Extract of Chamomile, Aloe Vera, and Green Tea on the Diabetic Wound in Rats

Clinical effects of Hibiscus sabdariffa Linn. on obesity treatment: A systematic review and meta-analysis of randomized controlled trials

IntroductionObesity is associated with many chronic non-communicable diseases, including hypertension, diabetes, cardiovascular and cerebrovascular diseases, cancer, gallbladder disease, bone and joint disorders, skin diseases, fatty liver disease, etc. (Wharton et al., 2020)1 The recent report revealed that overweight and obesity were prevalent in 60 % of the adult population. Several studies have been published to determine the effect of Hibiscus sabdariffa Linn. on obesity treatment, but the findings are still inconclusive. The purpose of this study was to determine the efficacy and safety of H. sabdariffa Linn in the treatment of obesity. MethodsWe searched PubMed, EMBASE, and CENTRAL from inception to February 2024. Randomized controlled trials (RCTs) were included if they explored the effect of H. sabdariffa on one of the following outcomes: body weight, body mass index (BMI), waist circumference, and waist-to-hip ratio. A random-effects model was used to meta-analyze the data. I2 was used to quantify statistical heterogeneity among the included RCTs. PROSPERO registered protocol: CRD42023408880. ResultsA total of six RCTs with 339 participants were included. Four trials used H. sabdariffa extract in capsules as the intervention of interest compared to placebo, while the other two trials used H. sabdariffa tea compared to black or green tea. Our meta-analyses showed that the mean difference in weight reduction between H. sabdariffa and control was − 0.27 kg (95 % confidence interval (CI); − 1.98 to 1.42, I2 = 0.0 %). The mean differences for BMI and waist circumference reduction were − 0.06 kg/m2 (95 % CI; − 0.58 to 0.47, I2 = 0.0 %) and − 0.20 centimeters (95 % CI; − 2.06 to 1.66, I2 = 0.00 %). No safety concerns were reported in the included studies. ConclusionOur study did not show a clinical benefit of H. sabdariffa extract in obesity treatment. However, further high-quality RCTs with a longer treatment duration and a standard dose are still warranted.

Exploring microbial and moist-heat effects on Pu-erh tea volatiles and understanding the methoxybenzene formation mechanism using molecular sensory science

Piling fermentation (PF) is crucial for Pu-erh tea aroma, yet its microbial and moist-heat impact on aroma quality is poorly understood. Solid-phase microextraction, solvent-assisted flavor evaporation, and gas chromatography–mass spectrometry were used to detected and analyses the samples of sun-green green tea, sterile PF and spontaneous PF. Microbiological action promotes the formation of stale aromas. Moist-heat action promotes the formation of plum-fragrance and sweet aroma. 20 microbial markers and 28 moist-heat markers were screened from 184 volatile components. Combining odor activity values and gas chromatography-olfactometry, 22 aroma-active compounds were screened (1,2,3-trimethoxybenzene, linalool, 1,2,4-trimethoxybenzene …), and analyzed during PF processing. Aroma omission and addition experiments verified its importance. Gallic acid addition experiments successfully verified that microorganisms are the main contributors to the synthesis of methoxybenzenes. Finally, Blastobotrys, Rasamsonia, and Thermomyces showed positive correlation with the synthesis of 1-ethyl-4-methoxybenzene, 1,2,4-trimethoxybenzene, 1,2,3-trimethoxybenzene, and 1,2-dimethoxybenzene. The formation mechanism of Pu-erh tea's aroma was clarified.Exploring microbial and moist-heat effects on Pu-erh tea volatiles and understanding the methoxybenzene formation mechanism using molecular sensory science.

Changes in proteolysis and volatile fraction of nitrite‐free Italian‐type salami modified in formulation and processing

SummaryNitrite in meat products exerts multiple functions in terms of safety and quality, but it has been related to an increased risk of health issues, and alternatives have been investigated. In this study, Italian‐style salamis were prepared with nitrite and ascorbate (CNO2), without nitrite and ascorbate (C0) and without nitrite and with ascorbate, green tea, grape seed and olive extracts (C0A). The products showed specific features in terms of peptides, free amino acids and volatiles, according to the technology applied for their production. The variations in peptides and free amino acids are likely due to process modifications, as the applied temperature and the time needed for pH decrease. Most volatile compounds, whether generated by known biochemical pathways or by ingredients (spices), differed between salami groups. The changes detected in the chemical parameters analysed provide some insights into the impact on product characteristics due to the process changes applied to replace nitrite removal.

METABOLOMIC TECHNIQUE IN GREEN TEA RESEARCH: A REVIEW

Tea, consumed by two-thirds of the global population, had a production of 5.68 million tons in 2017. The cultivation and processing of tea are crucial variables that have a substantial impact on the final product. As a result, many types of tea, such as black, oolong, and green, are produced, each with its own unique flavors and health advantages. Metabolomic techniques, which employ advanced analytical methods, are employed to characterize chemical composition of tea, thereby enabling the assessment of its quality, origin, and bioactivity. This review focused on the application of these techniques to the green tea research. Analytical methods such as UPLC-MS and 1H NMR, when employed in conjunction with multivariate analysis, have proven effective in correlating green tea quality with its chemical constituents, identifying key metabolites such as EGCG, ECG, and caffeine. These metabolomic techniques permit rapid and accurate assessments, enabling the differentiation between high- and low-quality green tea and enhancing the comprehension of its chemical composition and sensory attributes. In addition, a metabolomic approach was employed, utilizing HPLC-TOF-MS, to differentiate between various types of green tea based on their bioactivities. These methods have the capacity to reveal significant variations in metabolite profiles and bioactivities. The application of multivariate analysis enabled the identification of specific bioactive cultivars, thereby demonstrating the efficacy of the technique in evaluating the health-promoting effects of different tea samples. Thus, metabolomic methods represent an optimal approach for a comprehensive and expeditious investigation of the research related to green tea.

Sustainable analytical method for determination of bioactive compounds in solid oral formulations (capsules and tablets) containing green tea (Camellia sinensis) marketed in Brazil

This study presents the development of a sustainable analytical method using high-performance liquid chromatography (HPLC) for determination and quantification of bioactive compounds in Herbal Dietary Supplements (HDS) solid oral formulations containing green tea (Camellia sinensis). Four compounds [gallic acid, (+)-catechin, caffeine and caffeic acid] were determined in fifteen HDS samples (capsules and tablets) containing green tea marketed in Brazil. After optimizing the extraction process using factorial planning and response surface analysis, it was possible to develop the method. Methanol and acetic acid (0.25%) were components of the mobile phase, showing it as a more sustainable alternative to the use of acetonitrile. The samples evaluated demonstrated a lack of standardization in the concentrations (in mg g−1) of the chemical markers studied gallic acid (<LOD to 1.39), (+)-catechin (<LOD to 13.8), caffeine (<LOQ to 22) and caffeic acid (<LOD to 1.7). This concern has driven significant scientific research on the topic. The chromatographic method proved to be effective, sensitive and robust for qualification and quantification of the 4 chemical markers studied. This study found variations in the levels of chemical markers in HDS containing green tea sold in Brazil. Therefore, it can contribute to the regulation and quality control of these solid oral products (capsules and tablets) containing this plant.

Discrepancy on the flavor compound affect the quality of Taiping Houkui tea from different production regions

Taiping Houkui (TPHK) is prevalent green tea in China, its flavor quality is significantly influenced by different production regions. However, the key flavor compounds responsible for these discrepancies remain unclearly. Here, TPHK samples were produced from fresh leaves of ‘Shidacha 2’ cultivar planted in 14 distinct production regions. In 14 TPHK samples, a total of 33 non-volatile compounds were identified and quantified. Partial least-squares discriminant analysis (PLS-DA) reveal that theanine and glutamate were the main umami compounds, caffeine imparted with bitterness, which collectively contributed to the variation in the taste flavor of TPHK across different production regions. Furthermore, the profiles of 51 volatile compounds were determined, integrated PLS-DA with odor activity values of volatiles indicated that linalool (165.7–888.5) and geraniol (11.9–141.4) affecting the floral aroma of TPHK among different production regions. Our findings revealed the critical compounds that contributed to the effect of production regions on flavor quality of TPHK.

COMPARISON OF THE ANTIFUNGAL ACTIVITY OF BLACK, WHITE, AND GREEN TEA KOMBUCHA EXTRACTS AGAINST DERMATOPHYTE FUNGI

Kombucha is obtained by fermentation of tea and sugar by bacteria and yeast. This beverage has several beneficial effects, including antimicrobial activity. The objective of this study was to evaluate the antifungal activity of Kombucha extracts against dermatomycosis-causing fungi. Different types of Kombucha (black, white, green tea) and times of fermentation (10, 20, 30 days) were evaluated. Kombuchas were filtered, and extracts obtained by liquid-liquid extraction with ethyl acetate. Minimum inhibitory concentrations (MIC) were determined against clinical isolates of dermatophytes Trichophyton rubrum and T. mentagrophytes by broth microdilution. Toxicity tests and high-performance liquid chromatography (HPLC) were also performed. MIC ranged from 62.5–2000 μg/mL. Green tea Kombucha and 10-days fermentation extracts showed the best results. Toxicity was observed only for white tea Kombucha. Despite the chromatographic profiles, further studies are needed to characterize the active molecules. However, Kombucha extracts may constitute a viable alternative for new treatment strategies against dermatomycosis.

The Effect of the Addition of Spirulina spp. on the Quality Properties, Health Benefits, and Sensory Evaluation of Green Tea Kombucha

The Effect of the Addition of Spirulina spp. on the Quality Properties, Health Benefits, and Sensory Evaluation of Green Tea Kombucha

Cardiovascular Effects of Herbal Products and Their Interaction with Antihypertensive Drugs-Comprehensive Review.

Hypertension is a highly prevalent population-level disease that represents an important risk factor for several cardiovascular complications and occupies a leading position in mortality statistics. Antihypertensive therapy includes a wide variety of drugs. Additionally, the potential antihypertensive and cardioprotective effects of several phytotherapy products have been evaluated, as these could also be a valuable therapeutic option for the prevention, improvement or treatment of hypertension and its complications. The present review includes an evaluation of the cardioprotective and antihypertensive effects of garlic, Aloe vera, green tea, Ginkgo biloba, berberine, ginseng, Nigella sativa, Apium graveolens, thyme, cinnamon and ginger, and their possible interactions with antihypertensive drugs. A literature search was undertaken via the PubMed, Google Scholar, Embase and Cochrane databases. Research articles, systematic reviews and meta-analyses published between 2010 and 2023, in the English, Hungarian, and Romanian languages were selected.

3D Printed Hydrogel Sensor for Rapid Colorimetric Detection of Salivary pH.

Salivary pH is one of the crucial biomarkers used for non-invasive diagnosis of intraoral diseases, as well as general health conditions. However, standard pH sensors are usually too bulky, expensive, and impractical for routine use outside laboratory settings. Herein, a miniature hydrogel sensor, which enables quick and simple colorimetric detection of pH level, is shown. The sensor structure was manufactured from non-toxic hydrogel ink and patterned in the form of a matrix with 5 mm × 5 mm × 1 mm individual sensing pads using a 3D printing technique (bioplotting). The authors' ink composition, which contains sodium alginate, polyvinylpyrrolidone, and bromothymol blue indicator, enables repeatable and stable color response to different pH levels. The developed analysis software with an easy-to-use graphical user interface extracts the R(ed), G(reen), and B(lue) components of the color image of the hydrogel pads, and evaluates the pH value in a second. A calibration curve used for the analysis was obtained in a pH range of 3.5 to 9.0 using a laboratory pH meter as a reference. Validation of the sensor was performed on samples of artificial saliva for medical use and its mixtures with beverages of different pH values (lemon juice, coffee, black and green tea, bottled and tap water), and correct responses to acidic and alkaline solutions were observed. The matrix of square sensing pads used in this study provided multiple parallel responses for parametric tests, but the applied 3D printing method and ink composition enable easy adjustment of the shape of the sensing layer to other desired patterns and sizes. Additional mechanical tests of the hydrogel layers confirmed the relatively high quality and durability of the sensor structure. The solution presented here, comprising 3D printed hydrogel sensor pads, simple colorimetric detection, and graphical software for signal processing, opens the way to development of miniature and biocompatible diagnostic devices in the form of flexible, wearable, or intraoral sensors for prospective application in personalized medicine and point-of-care diagnosis.

Correction to: Inhibition of Pectobacterium carotovorum-mediated potato soft rot by carboxymethyl cellulose-based antibacterial edible coating containing green tea extract

Correction to: Inhibition of Pectobacterium carotovorum-mediated potato soft rot by carboxymethyl cellulose-based antibacterial edible coating containing green tea extract

Polyphenols improve non-alcoholic fatty liver disease via gut microbiota: A comprehensive review.

Polyphenols, natural micronutrients derived from plants, are valued for their anti-inflammatory and antioxidant properties. The escalating global prevalence of non-alcoholic fatty liver disease (NAFLD) underscores its status as a chronic progressive liver condition. Furthermore, the dysregulation of gut microbiota (GM) is implicated in the onset and progression of NAFLD through the actions of metabolites such as bile acids (BAs), lipopolysaccharide (LPS), choline, and short-chain fatty acids (SCFAs). Additionally, GM may influence the integrity of the intestinal barrier. This review aims to evaluate the potential effects of polyphenols on GM and intestinal barrier function, and their subsequent impact on NAFLD. We searched through a wide range of databases, such as Web of Science, PubMed, EMBASE, and Scopus to gather information for our non-systematic review of English literature. GM functions and composition can be regulated by polyphenols such as chlorogenic acid, curcumin, green tea catechins, naringenin, quercetin, resveratrol, and sulforaphane. Regulating GM composition improves NAFLD by alleviating inflammation, liver fat accumulation, and liver enzymes. Furthermore, it improves serum lipid profile and gut barrier integrity. All of these components affect NAFLD through the metabolites of GM, including SCFAs, choline, LPS, and BAs. Current evidence indicates that chlorogenic acid, resveratrol, quercetin, and curcumin can modulate GM, improving intestinal barrier integrity and positively impacting NAFLD. More studies are necessary to evaluate the safety and efficacy of naringenin, sulforaphane, and catechin.

Green tea polyphenols reduced Porphyromonas gingivalis virulence and ameliorated aggravated gut inflammation by improving immunity and gut microbiota dysbiosis

Porphyromonas gingivalis (PG), a key periodontal pathogen, has been implicated in various systemic diseases, including colorectal cancer and cardiovascular diseases. However, its potential role in promoting gut inflammation and the underlying mechanisms remain unclear. Furthermore, multiple studies have reported an association between tea polyphenols and a reduced risk of periodontal disease and colitis, but it remains unclear whether they play a role in mitigating gut inflammation exacerbated by PG. In this study, we demonstrated that Tea polyphenols (TP) reduced the activity of PG and lowered the expression levels of virulence factors. Intervention with TP can prevent the worsening of gut inflammation exacerbated by PG, including body weight loss and shortened colon length. TP not only alleviated the differentiation of Th17 cells and the secretion of related cytokines but also promoted the enrichment of potentially beneficial bacteria like Ruminococcus and Lactobacillus. Metabolomics revealed that TP enriched potential beneficial microbial metabolites, such as secondary bile acids, and showed certain correlations with immune-related markers.

L-Theanine Prolongs the Lifespan by Activating Multiple Molecular Pathways in Ultraviolet C-Exposed Caenorhabditis elegans.

L-theanine, a unique non-protein amino acid, is an important bioactive component of green tea. Previous studies have shown that L-theanine has many potent health benefits, such as anti-anxiety effects, regulation of the immune response, relaxing neural tension, and reducing oxidative damage. However, little is known concerning whether L-theanine can improve the clearance of mitochondrial DNA (mtDNA) damage in organisms. Here, we reported that L-theanine treatment increased ATP production and improved mitochondrial morphology to extend the lifespan of UVC-exposed nematodes. Mechanistic investigations showed that L-theanine treatment enhanced the removal of mtDNA damage and extended lifespan by activating autophagy, mitophagy, mitochondrial dynamics, and mitochondrial unfolded protein response (UPRmt) in UVC-exposed nematodes. In addition, L-theanine treatment also upregulated the expression of genes related to mitochondrial energy metabolism in UVC-exposed nematodes. Our study provides a theoretical basis for the possibility that tea drinking may prevent mitochondrial-related diseases.

Improving efficiency in green tea production time using lean manufacturing approach with value stream mapping: A case study at PT Candi Loka [Perbaikan efisiensi waktu produksi teh hijau menggunakan pendekatan produksi ramping dengan value stream mapping: Studi kasus di PT Candi Loka

Green tea production activities at PT Candi Loka indicated a time-consuming, which caused process efficiency to be less than optimal. Process efficiency improvements must be made to increase company competitiveness and consumer satisfaction. This research aimed to analyze the efficiency of green tea production time at PT Candi Loka by identifying the processing time required in each production activity, including the time consumption and formulating recommendations for improvement using a lean manufacturing approach using the VSM (Value Stream Mapping) method. There were 30 activities in 6 processes consisting of receiving raw materials, withering, rolling, drying, and packaging. Identification of value streams using the PAM (Process Activity Mapping) tool produced 9 Value added (VA) activities, 19 Necessary but Non-Value Added (NNVA) activities, and 2 Non-Value Added (NVA) activities in the form of delays in the withering and drying processes. In the current state map analysis, the production lead time value was 315.286 seconds. Recommended improvements to eliminate delays in the withering process were to set up the rotary panner machine earlier and increase the number of supervisors, while to eliminate delays in the drying process were to implement a piece rate system. Increasing efficiency was also carried out by improving NNVA activities by adding weighbridge facilities and using a conveyor system. The future state map proposed by implementing recommended improvements resulted in an increase in production time efficiency to 222.356 seconds and an increase in the process cycle efficiency value from 58.95% to 84.85%.

Epigallocatechin gallate modulates ferroptosis through downregulation of tsRNA-13502 in non-small cell lung cancer

Ferroptosis, an iron-dependent regulated cell death mechanism, holds significant promise as a therapeutic strategy in oncology. In the current study, we explored the regulatory effects of epigallocatechin gallate (EGCG), a prominent polyphenol in green tea, on ferroptosis and its potential therapeutic implications for non-small cell lung cancer (NSCLC). Treatment of NSCLC cell lines with varying concentrations of EGCG resulted in a notable suppression of cell proliferation, as evidenced by a reduction in Ki67 immunofluorescence staining. Western blot analyses demonstrated that EGCG treatment led to a decrease in the expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) while increasing the levels of acyl-CoA synthetase long-chain family member 4 (ACSL4). These molecular changes were accompanied by an increase in intracellular iron, malondialdehyde (MDA), and reactive oxygen species (ROS), alongside ultrastructural alterations characteristic of ferroptosis. Through small RNA sequencing and RT-qPCR, transfer RNA-derived small RNA 13502 (tsRNA-13502) was identified as a significant target of EGCG action, with its expression being upregulated in NSCLC tissues compared to adjacent non-tumorous tissues. EGCG was found to modulate the ferroptosis pathway by downregulating tsRNA-13502 and altering the expression of key ferroptosis regulators (GPX4/SLC7A11 and ACSL4), thereby promoting the accumulation of iron, MDA, and ROS, and ultimately inducing ferroptosis in NSCLC cells. This study elucidates EGCG’s multifaceted mechanisms of action, underscoring the modulation of ferroptosis as a viable therapeutic approach for enhancing NSCLC treatment outcomes.

Investigating the Formation of In Vitro Immunogenic Gluten Peptides after Covalent Modification of Their Structure with Green Tea Phenolic Compounds under Alkaline Conditions.

Celiac disease is an autoimmune disorder triggered by immunogenic gluten peptides produced during gastrointestinal digestion. To prevent the production of immunogenic gluten peptides, the stimulation of covalent-type protein-polyphenol interactions may be promising. In this study, gluten interacted with green tea extract (GTE) at pH 9 to promote the covalent-type gluten-polyphenol interactions, and the number of immunogenic gluten peptides, 19-mer, 26-mer, and 33-mer, was monitored after in vitro digestion. Treatment of gluten with GTE provided an increased antioxidant capacity, decreased amino group content, and increased thermal properties. More importantly, there was a remarkable (up to 73%) elimination of immunogenic gluten peptide release after the treatment of gluten with 2% GTE at 50 °C and pH 9 for 2 h. All of these confirmed that gluten was efficiently modified by GTE polyphenols under the stated conditions. These findings are important in developing new strategies for the development of gluten-free or low-gluten food products with reduced immunogenicity.