Displaying publications 1 - 20 of 107 in total

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  1. Adsorption and desorption characteristics of flavonoids from white tea using macroporous adsorption resin
    Yang Y, Liang Q, Zhang B, Zhang J, Fan L, Kang J, et al.
    J Chromatogr A, 2024 Jan 25;1715:464621.
    PMID: 38198876 DOI: 10.1016/j.chroma.2023.464621
    White tea contains the highest flavonoids compared to other teas. While there have been numerous studies on the components of different tea varieties, research explicitly focusing on the flavonoid content of white tea remains scarce, making the need for a good flavonoid purification process for white tea even more important. This study compared the adsorption and desorption performance of five types of macroporous resins: D101, HP20, HPD500, DM301, and AB-8. Among the tested resins, AB-8 was selected based on its best adsorption and desorption performance to investigate the static adsorption kinetics and dynamic adsorption-desorption purification of white tea flavonoids. The optimal purification process was determined: adsorption temperature 25 °C, crude tea flavonoid extract pH 3, ethanol concentration 80 %, sample loading flow rate and eluent flow rate 1.5 BV/min, and eluent dosage 40 BV. The results indicated that the adsorption process followed pseudo-second-order kinetics. Under the above purification conditions, the purity of the total flavonoids in the purified white tea flavonoid increased from approximately 17.69 to 46.23 %, achieving a 2.61-fold improvement, indicating good purification results. The purified white tea flavonoid can be further used for nutraceutical and pharmaceutical applications.
    Matched MeSH terms: Tea
  2. The occurrence and probabilistic risk of exposure to parabens from bottled and hand-shaken teas in the general adult population of Taiwan
    Chin WS, Chang CH, Say YH, Chuang YN, Wang JN, Kao HC, et al.
    Environ Sci Pollut Res Int, 2024 Jan;31(3):4518-4527.
    PMID: 38102436 DOI: 10.1007/s11356-023-31348-0
    Parabens (PBs) are esters of p-hydroxybenzoic acid, and there are growing concerns due to their potential to disrupt endocrine function and their wide use as preservatives in foodstuffs, including beverages. The consumption of bottled and hand-shaken teas is gradually replacing traditional tea consumption through brewing. However, no study has reported PB concentrations in different types of teas or packaging and their associated health risks. Our aim was to determine the concentration of PBs (methyl- (MetPB), ethyl- (EthPB), propyl- (PropPB), butyl-paraben (ButPB)) in green, black, and oolong teas in two varieties of products (bottled and hand-shaken teas), using UPLC-MS/MS. Additionally, we estimated the health risks associated with tea consumption in the general adult population of Taiwan. A Monte Carlo simulation was applied to estimate the distribution of daily PB intake through bottled (n = 79) and hand-shaken (n = 71) tea consumption. Our findings revealed geometric mean concentrations in bottled green/black/oolong teas were 714.1/631.2/532.1 ng/L for MetPB, 95.2/ 30.5/14.9 ng/L for EthPB, 77.9/28.3/non-detected (ND) ng/L for PropPB, and 69.3/26.6/ND ng/L for ButPB. Hand-shaken green/black/oolong teas exhibited concentrations of 867.5/2258/1307 ng/L for MetPB, 28.5/28.8/14.5 ng/L for EthPB, 25.4/18.3/17.8 ng/L for PropPB, and 30.3/18.0/15.5 ng/L for ButPB. The median MetPB concentrations in hand-shaken black (2333 ng/L) and oolong teas (1215 ng/L) were significantly higher than those in bottled black (595.4 ng/L) and oolong teas (489.3 ng/L). Conversely, median concentrations of EthPB, PropPB, and ButPB in bottled teas were significantly higher than those in hand-shaken teas. MetPB was the predominant PB, constituting 73.2-91.9% in bottled teas and 85-94% in hand-shaken teas. Our results showed no health risks associated with bottled or hand-shaken tea consumption based on reference doses. However, the study highlights the importance of continued vigilance given the potential chronic exposure to PBs from various sources, necessitating ongoing concern despite the absence of immediate risks from tea consumption.
    Matched MeSH terms: Tea
  3. Fulltext Research on an innovative design and evaluation method of Chinese tea sets based on GT-AHP-FCE
    Zhao Y, Hamat B, Wang T, Wang S, Pang LLL
    PLoS One, 2024;19(4):e0302005.
    PMID: 38603676 DOI: 10.1371/journal.pone.0302005
    AIMS: In order to explore new consumer demands for Chinese tea set products, propose an innovative tea set product design and evaluation method to improve the user experience and satisfaction of the produced tea sets, thereby promoting the development of the tea set market and the promotion of tea culture.

    METHODS: Firstly, grounded theory (GT) was used to analyze interview data to extract consumer demand indicators and construct a design evaluation hierarchical model. Secondly, the Analytical Hierarchy Process (AHP) was used to calculate the weights of the indicators, determine their priority of importance, and obtain several indicators that have a greater impact on the tea set design to guide innovative design practice. Lastly, the tea set design schemes were evaluated using the fuzzy comprehensive evaluation method to select the optimal design scheme and also to act as a guideline for further design optimization.

    CONCLUSION: This study explores the innovative design and evaluation method for tea set products based on GT-AHP-FCE and validates the feasibility of this approach through a practical example of tea set design inspired by "The Classic of Mountains and Seas.". It provides innovative theoretical and practical guidance for designers of subsequent tea set products and also provides a new path for the inheritance and innovation of traditional culture.

    Matched MeSH terms: Tea*
  4. Spent tea waste extract as a green modifying agent of chitosan for aspirin adsorption: Fixed-bed column, modeling and toxicity studies
    Nordin AH, Ngadi N, Nordin ML, Noralidin NA, Nabgan W, Osman AY, et al.
    Int J Biol Macromol, 2023 Dec 31;253(Pt 2):126501.
    PMID: 37678687 DOI: 10.1016/j.ijbiomac.2023.126501
    Aspirin is a prevalent over-the-counter medicine that has been categorized as an emerging contaminant due to its danger to both living things and the environment. This work presents chitosan modified with spent tea waste extract (STWE) via the wet impregnation method as an adsorbent for the enhanced removal of aspirin in a fixed-bed column. The adsorbent (named chitosan-STWE) was successfully synthesized and exhibited a low crystallinity structure, good stability against thermal and acidic conditions, as depicted by HNMR, XRD, TGA, and the dissolution rate of the adsorbent. The adsorption column study reveals that increasing bed height (up to 6 cm) increases the percentage of aspirin removal (up to 40.8 %). Increasing aspirin concentration enhances the amount of aspirin that comes into contact with the chitosan-STWE adsorbent, thereby increasing the adsorption capacity. On the other hand, higher flow rates result in shorter contact times between the adsorbent and adsorbates, which lowers the quantity of aspirin adsorbed. The experimental data are in accordance with the values generated by the Thomas and Yoon-Nelson models, with the maximum adsorption capacity of 61.7 mg/g. The chitosan-STWE adsorbent was determined to be non-toxic, thus safe to be used in wastewater treatment applications.
    Matched MeSH terms: Tea
  5. Green surface functionalization of chitosan with spent tea waste extract for the development of an efficient adsorbent for aspirin removal
    Nordin AH, Ngadi N, Ilyas RA, Abd Latif NAF, Nordin ML, Mohd Syukri MS, et al.
    Environ Sci Pollut Res Int, 2023 Dec;30(60):125048-125065.
    PMID: 36795217 DOI: 10.1007/s11356-023-25816-w
    This study investigates the feasibility of spent tea waste extract (STWE) as a green modifying agent for the modification of chitosan adsorbent towards aspirin removal. Response surface methodology based on Box-Behnken design was employed to find the optimal synthesis parameters (chitosan dosage, spent tea waste concentration, and impregnation time) for aspirin removal. The results revealed that the optimum conditions for preparing chitotea with 84.65% aspirin removal were 2.89 g of chitosan, 18.95 mg/mL of STWE, and 20.72 h of impregnation time. The surface chemistry and characteristics of chitosan were successfully altered and improved by STWE, as evidenced by FESEM, EDX, BET, and FTIR analysis. The adsorption data were best fitted to pseudo 2nd order, followed by chemisorption mechanisms. The maximum adsorption capacity of chitotea was 157.24 mg/g, as fitted by Langmuir, which is impressive for a green adsorbent with a simple synthesis method. Thermodynamic studies demonstrated the endothermic nature of aspirin adsorption onto chitotea.
    Matched MeSH terms: Tea
  6. Fulltext Epigallocatechin-3-Gallate Therapeutic Potential in Cancer: Mechanism of Action and Clinical Implications
    Kciuk M, Alam M, Ali N, Rashid S, Głowacka P, Sundaraj R, et al.
    Molecules, 2023 Jul 06;28(13).
    PMID: 37446908 DOI: 10.3390/molecules28135246
    Cellular signaling pathways involved in the maintenance of the equilibrium between cell proliferation and apoptosis have emerged as rational targets that can be exploited in the prevention and treatment of cancer. Epigallocatechin-3-gallate (EGCG) is the most abundant phenolic compound found in green tea. It has been shown to regulate multiple crucial cellular signaling pathways, including those mediated by EGFR, JAK-STAT, MAPKs, NF-κB, PI3K-AKT-mTOR, and others. Deregulation of the abovementioned pathways is involved in the pathophysiology of cancer. It has been demonstrated that EGCG may exert anti-proliferative, anti-inflammatory, and apoptosis-inducing effects or induce epigenetic changes. Furthermore, preclinical and clinical studies suggest that EGCG may be used in the treatment of numerous disorders, including cancer. This review aims to summarize the existing knowledge regarding the biological properties of EGCG, especially in the context of cancer treatment and prophylaxis.
    Matched MeSH terms: Tea
  7. Tea Polyphenols Inhibit the Activity and Toxicity of Staphylococcus aureus by Destroying Cell Membranes and Accumulating Reactive Oxygen Species
    Zhong W, Tang M, Xie Y, Huang X, Liu Y
    Foodborne Pathog Dis, 2023 Jul;20(7):294-302.
    PMID: 37347934 DOI: 10.1089/fpd.2022.0085
    Staphylococcus aureus can cause bacterial food intoxication and seriously affect human health. Tea polyphenols (TP) are a kind of natural, safe, and broad-spectrum bacteriostatic substances, with a wide range of bacteriostatic effects. In the study, we explored the possible bacteriostatic mode of TP. The minimum inhibitory concentration of TP against S. aureus was 64 μg/mL. Protein, DNA, and K+ leak experiments, fluorescence microscopy, and transmission electron microscopy suggested that TP disrupt cell membranes, leading to intracellular component loss. By studying the effect of TP on the toxicity of S. aureus, it was found that the expression levels of two toxin genes, coa and spa, were downregulated by 2.37 and 32.6, respectively. Furthermore, after treatment with TP, a large number of reactive oxygen species (ROS) were propagated and released, leading to oxidative stress in cells. We speculated that the bacteriostatic mechanism of TP may be through the destruction of the cell membrane and ROS-mediated oxidative stress. Meanwhile, the hemolysis activity proved the safety of TP. Our results suggested that TP may be a potential antimicrobial agent for food.
    Matched MeSH terms: Tea
  8. Metabolomics in tea products; a compile of applications for enhancing agricultural traits and quality control analysis of Camellia sinensis
    Farag MA, Elmetwally F, Elghanam R, Kamal N, Hellal K, Hamezah HS, et al.
    Food Chem, 2023 Mar 15;404(Pt B):134628.
    PMID: 36283313 DOI: 10.1016/j.foodchem.2022.134628
    Tea is one of the world's most popular beverages, with several health benefits. Polyphenols are the predominant constituents to account for its health benefits. Despite the well-known benefits of tea on health, the uniqueness of its aroma, taste, and features is an added value that contribute to the increased popularity of this beverage worldwide, and they are associated with the alterations in the metabolites during tea processing and cultivation. The manufacturing of tea consists of several stages with various processes as withering, fixing, rolling, fermentation and drying. The classification into tea types is according to such processing. The high-quality production of the various tea classes also depends on agricultural conditions, such as shading, plucking, climate, and soil composition. Metabolomics is well recognized as an effective tool for evaluating the quality of tea products. Applications in controlling the quality of tea products and adulterant detection are discussed in this review.
    Matched MeSH terms: Tea/metabolism
  9. Fulltext Influence of different processing method on lignan content of selected Malaysian plant-based foods
    Hussain Zaki UK, Fryganas C, Trijsburg L, Feskens EJM, Capuano E
    Food Chem, 2023 Mar 15;404(Pt A):134607.
    PMID: 36272303 DOI: 10.1016/j.foodchem.2022.134607
    This research assessed the influence of pickling, fermentation, germination, and tea brewing on lignan content of a variety of food highly consumed in Malaysia. Lignans have been measured by a validated LC-MS/MS method. Secoisolariciresinol (SECO) was the most abundant compound in fermented and germinated samples. Pickling significantly decreased larisiresinol content by approximately 86 %. Fermentation increased lignan content in a mixture of flaxseed and mung beans (799.9 ± 67.4 mg/100 g DW) compared to the unfermented counterpart (501.4 ± 134.6 mg/100 g DW), whereas the fermentation of soybeans and mung beans did not significantly affect the SECO content. Germination increased lignan content, which reached its peak on day 6 of germination for all the tested matrixes. In tea brew, lignans concentration increased with brewing time reaching its highest concentration at 10 min of brewing. The results of this study expand the knowledge on the effect of processing on lignan content in food.
    Matched MeSH terms: Tea
  10. Fulltext Genomic selection strategies to increase genetic gain in tea breeding programs
    Lubanga N, Massawe F, Mayes S, Gorjanc G, Bančič J
    Plant Genome, 2023 Mar;16(1):e20282.
    PMID: 36349831 DOI: 10.1002/tpg2.20282
    Tea [Camellia sinensis (L.) O. Kuntze] is mainly grown in low- to middle-income countries (LMIC) and is a global commodity. Breeding programs in these countries face the challenge of increasing genetic gain because the accuracy of selecting superior genotypes is low and resources are limited. Phenotypic selection (PS) is traditionally the primary method of developing improved tea varieties and can take over 16 yr. Genomic selection (GS) can be used to improve the efficiency of tea breeding by increasing selection accuracy and shortening the generation interval and breeding cycle. Our main objective was to investigate the potential of implementing GS in tea-breeding programs to speed up genetic progress despite the low cost of PS in LMIC. We used stochastic simulations to compare three GS-breeding programs with a Pedigree and PS program. The PS program mimicked a practical commercial tea-breeding program over a 40-yr breeding period. All the GS programs achieved at least 1.65 times higher genetic gains than the PS program and 1.4 times compared with Seed-Ped program. Seed-GSc was the most cost-effective strategy of implementing GS in tea-breeding programs. It introduces GS at the seedlings stage to increase selection accuracy early in the program and reduced the generation interval to 2 yr. The Seed-Ped program outperformed PS by 1.2 times and could be implemented where it is not possible to use GS. Our results indicate that GS could be used to improve genetic gain per unit time and cost even in cost-constrained tea-breeding programs.
    Matched MeSH terms: Tea
  11. Influence of chicken feather waste derived protein hydrolysate on the growth of tea plants under different application methods and fertilizer rates
    Raguraj S, Kasim S, Jaafar NM, Nazli MH
    Environ Sci Pollut Res Int, 2023 Mar;30(13):37017-37028.
    PMID: 36564696 DOI: 10.1007/s11356-022-24758-z
    Modern agriculture prioritizes eco-friendly and sustainable strategies to enhance crop growth and productivity. The utilization of protein hydrolysate extracted from chicken feather waste as a plant biostimulant paves the path to waste recycling. A greenhouse experiment was performed to evaluate the implications of different doses (0, 1, 2, and 3 g L-1) of chicken feather protein hydrolysate (CFPH), application method (soil and foliar), and fertilizer rate (50% and 100%) on the growth performance of tea nursery plants. The highest dose of CFPH (3 g L-1) increased the shoot and root dry weights by 43% and 70%, respectively over control. However, no significant differences were observed between 2 and 3 g L-1 doses in plant dry weight, biometric, and root morphological parameters. Foliar application of CFPH significantly increased all the growth parameters compared to soil drenching except N, P, and K concentrations in leaves and roots. Plants grown under 100% fertilizer rate showed better growth performance than 50% fertilizer rate. Tea nursery plants treated with foliar 2 g L-1 dose and grown under full fertilizer rate recorded the highest plant dry weight, root length, and root surface area. However, tea plants under 50% fertilizer rate and treated with foliar 2 and 3 g L-1 doses sustained the growth similar to untreated plants under 100% fertilizer rate. The significantly higher N, P, and K concentrations in leaves were observed in plants treated with soil drenching of 2 and 3 g L-1 CFPH doses under 100% fertilizer rate. Our results indicate that the application of CFPH as a foliar spray is highly effective in producing vigorous tea nursery plants suitable for field planting, eventually capable of withstanding stress and higher yield.
    Matched MeSH terms: Tea
  12. Fulltext The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves
    Benjamin MAZ, Ng SY, Saikim FH, Rusdi NA
    Molecules, 2022 Sep 30;27(19).
    PMID: 36234995 DOI: 10.3390/molecules27196458
    The therapeutic potential of bamboos has acquired global attention. Nonetheless, the biological activities of the plants are rarely considered due to limited available references in Sabah, Malaysia. Furthermore, the drying technique could significantly affect the retention and degradation of nutrients in bamboos. Consequently, the current study investigated five drying methods, namely, sun, shade, microwave, oven, and freeze-drying, of the leaves of six bamboo species, Bambusa multiplex, Bambusa tuldoides, Bambusa vulgaris, Dinochloa sublaevigata, Gigantochloa levis, and Schizostachyum brachycladum. The infused bamboo leaves extracts were analysed for their total phenolic content (TPC) and total flavonoid content (TFC). The antioxidant activities of the samples were determined via the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays, whereas their toxicities were evaluated through the brine shrimp lethality assay (BSLA). The chemical constituents of the samples were determined using liquid chromatography−tandem mass spectrometry (LC-MS/MS). The freeze-drying method exhibited the highest phytochemical contents and antioxidant activity yield, excluding the B. vulgaris sample, in which the microwave-dried sample recorded the most antioxidant and phytochemical levels. The TPC and TFC results were within the 2.69 ± 0.01−12.59 ± 0.09 mg gallic acid equivalent (GAE)/g and 0.77 ± 0.01−2.12 ± 0.01 mg quercetin equivalent (QE)/g ranges, respectively. The DPPH and ABTS IC50 (half-maximal inhibitory concentration) were 2.92 ± 0.01−4.73 ± 0.02 and 1.89−0.01 to 3.47 ± 0.00 µg/mL, respectively, indicating high radical scavenging activities. The FRAP values differed significantly between the drying methods, within the 6.40 ± 0.12−36.65 ± 0.09 mg Trolox equivalent (TE)/g range. The phytochemical contents and antioxidant capacities exhibited a moderate correlation, revealing that the TPC and TFC were slightly responsible for the antioxidant activities. The toxicity assessment of the bamboo extracts in the current study demonstrated no toxicity against the BSLA based on the LC50 (lethal concentration 50) analysis at >1000 µg/mL. LC-MS analysis showed that alkaloid and pharmaceutical compounds influence antioxidant activities, as found in previous studies. The acquired information might aid in the development of bamboo leaves as functional food items, such as bamboo tea. They could also be investigated for their medicinal ingredients that can be used in the discovery of potential drugs.
    Matched MeSH terms: Tea
  13. Fulltext The Effect of Intragastric Gavage of High Dose Green Tea Extract on Serum Status of Magnesium, Calcium, and Zinc
    Khaleel AK, Shaari RB, Nawi MAA, Al-Yassiri AMH
    Asian Pac J Cancer Prev, 2022 Sep 01;23(9):3195-3199.
    PMID: 36172684 DOI: 10.31557/APJCP.2022.23.9.3195
    OBJECTIVE: Green tea (GT) contains polyphenolic flavonoids, different minerals like magnesium, calcium, and zinc, vitamins, amino acids, carbohydrates, proteins, and others. It has a different health benefit. The aim of the present study was to investigate the effect of intragastric gavage of a high dose GT extract on serum biochemical analysis of magnesium, calcium, and zincin juvenile Wistar albino rats.

    METHODS: Twelve rats were used in the study and divided in to two equal groups. All the animals in the control group were intragastically gavaged by distilled water and continues for ten days, from day 24 to day 34 of age, while the animals in the study group were intragastically gavaged by GT extract (300mg/kg/day) which continues also for ten days from day 24 to day 34 of age. On day 34 of age, and two hours after the last dose, the rats were anaesthetized and blood collection by cardiac puncture was taken.

    RESULTS: The results showed that the intragastric gavage of a high dose of GT extract caused a non-significant increase in serum magnesium, and calcium levels (p>0.05), but a significant increase in zinc serum level was seen(p< 0.05).

    CONCLUSION: GT can cause a significant increase in zinc serum level, and this may explain the significant role of GT in the response to different oxidative stress. It is recommended to measure the Zn serum level in rats after a period longer than two hrs from the time of the last dose of intragastric gavage of GT extract.

    Matched MeSH terms: Tea/chemistry
  14. Capillary electrophoresis-mass spectrometry analysis of bisphenol A and its analogues in bottled tea beverages with dynamic pH focusing
    Yahaya N, Huang ZA, Yan B, Chen DDY
    Food Chem, 2022 Mar 15;372:131220.
    PMID: 34607048 DOI: 10.1016/j.foodchem.2021.131220
    A simple and sensitive method for the determination of bisphenol A and its analogues at the ng/mL level in bottled tea beverages is presented. This method utilized a dynamic pH junction to focus the analyte into a more concentrated zone, based on the electrophoretic mobility difference of analytes in the sample matrix and background electrolytes in capillary electrophoresis coupled to mass spectrometry (CE-MS). The optimised analyte focusing led to enhanced signal detection with average peak heights for five bisphenols of 53-170 folds higher than conventional injections. Under optimised conditions, the method showed good linearity in the range of 0.1-100 ng/mL, excellent limits of detection (0.03-0.04 ng/mL), good analyte recovery (80.3-118.1%) with acceptable relative standard deviations (<12%). The limits of quantifications were below the maximum permissible content of bisphenol A set by the European Commission for this product. This method was used to quantitatively analyse bisphenols in six different kinds of bottled tea beverages, making it a promising tool for practical applications.
    Matched MeSH terms: Tea
  15. Cross-linked tannase-carbon nanotubes composite in elevating antioxidative potential of green tea extract
    Ong CB, Annuar MSM
    J Food Biochem, 2021 10;45(10):e13924.
    PMID: 34490635 DOI: 10.1111/jfbc.13924
    Multi-walled carbon nanotubes (MWCNT)-tannase composite was investigated as an immobilized biocatalyst on the basis of its facile preparation, low cost, and excellent aqueous dispersibility. Cross-linked tannase enzymes, obtained in the presence of glutaraldehyde, were composited with MWCNT via physical adsorption. Multiple techniques were applied to investigate, and corroborate the successful adsorption of cross-linked tannase onto the MWCNT structure. Green tea infusion extract post-treatment using the composite preparation showed elevated radical scavenging activities relative to the control. Green tea infusion extract exhibited a markedly reduced EC50 value on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals following its treatment with the enzyme composite, which represents 20%-34% enhancement in its free radical scavenging capacity. Stoichiometry and number of reduced DPPH were determined and compared. The antioxidative potential of a widely consumed, health-beneficial green tea is elevated by the treatment with MWCNT-tannase composite. PRACTICAL APPLICATIONS: Cross-linked tannase enzymes were composited with pristine multi-walled carbon nanotubes via simple physical adsorption. The composite presents key advantages such as low specific volume compared to other well-known immobilization media, inert, facile enzyme composition, and ease of recovery for repeated use. The work demonstrated carbon nanotube prosthetic utility in the biotransformation of food-based health commodity sought after for its nutritional benefits. The approach is of both industrial- and agricultural importance, and is a promising and viable strategy to obtain a natural, functional food supplement for the multi-billion dollar well-being and health-related industries.
    Matched MeSH terms: Tea
  16. Prediction of tea theanine content using near-infrared spectroscopy and flower pollination algorithm
    Ong P, Chen S, Tsai CY, Chuang YK
    Spectrochim Acta A Mol Biomol Spectrosc, 2021 Jul 05;255:119657.
    PMID: 33744842 DOI: 10.1016/j.saa.2021.119657
    In this study, near-infrared (NIR) spectroscopy was exploited for non-destructive determination of theanine content of oolong tea. The NIR spectral data (400-2500 nm) were correlated with the theanine level of 161 tea samples using partial least squares regression (PLSR) with different wavelengths selection methods, including the regression coefficient-based selection, uninformative variable elimination, variable importance in projection, selectivity ratio and flower pollination algorithm (FPA). The potential of using the FPA to select the discriminative wavelengths for PLSR was examined for the first time. The analysis showed that the PLSR with FPA method achieved better predictive results than the PLSR with full spectrum (PLSR-full). The developed simplified model using on FPA based on 12 latent variables and 89 selected wavelengths produced R-squared (R2) value and root mean squared error (RMSE) of 0.9542, 0.8794 and 0.2045, 0.3219 for calibration and prediction, respectively. For PLSR-full, the R2 values of 0.9068, 0.8412 and RMSEs of 0.2916, 0.3693, were achieved for calibration and prediction. Also, the optimized model using FPA outperformed other wavelengths selection methods considered in this study. The obtained results indicated the feasibility of FPA to improve the predictability of the PLSR and reduce the model complexity. The nonlinear regression models of support vector machine regression and Gaussian process regression (GPR) were further utilized to evaluate the superiority of using the FPA in the wavelength selection. The results demonstrated that utilizing the wavelength selection method of FPA and nonlinear regression model of GPR could improve the predictive performance.
    Matched MeSH terms: Tea
  17. Fulltext Anti-Influenza with Green Tea Catechins: A Systematic Review and Meta-Analysis
    Rawangkan A, Kengkla K, Kanchanasurakit S, Duangjai A, Saokaew S
    Molecules, 2021 Jun 30;26(13).
    PMID: 34209247 DOI: 10.3390/molecules26134014
    Influenza is one of the most serious respiratory viral infections worldwide. Although several studies have reported that green tea catechins (GTCs) might prevent influenza virus infection, this remains controversial. We performed a systematic review and meta-analysis of eight studies with 5,048 participants that examined the effect of GTC administration on influenza prevention. In a random-effects meta-analysis of five RCTs, 884 participants treated with GTCs showed statistically significant effects on the prevention of influenza infection compared to the control group (risk ratio (RR) 0.67, 95%CIs 0.51-0.89, P = 0.005) without evidence of heterogeneity (I2= 0%, P = 0.629). Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35-0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358). Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49-0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554). There were no obvious publication biases (Egger's test (P = 0.138) and Begg's test (P = 0.103)). Our analysis suggests that green tea consumption is effective in the prophylaxis of influenza infections. To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.
    Matched MeSH terms: Tea/chemistry*
  18. Fulltext Beneficial Effects of Green Tea Catechins on Female Reproductive Disorders: A Review
    Kamal DAM, Salamt N, Zaid SSM, Mokhtar MH
    Molecules, 2021 May 03;26(9).
    PMID: 34063635 DOI: 10.3390/molecules26092675
    Tea is one of the most widely consumed beverages worldwide after water, and green tea accounts for 20% of the total tea consumption. The health benefits of green tea are attributed to its natural antioxidants, namely, catechins, which are phenolic compounds with diverse beneficial effects on human health. The beneficial effects of green tea and its major bioactive component, (-)-epigallocatechin-3-gallate (EGCG), on health include high antioxidative, osteoprotective, neuroprotective, anti-cancer, anti-hyperlipidemia and anti-diabetic effects. However, the review of green tea's benefits on female reproductive disorders, including polycystic ovary syndrome (PCOS), endometriosis and dysmenorrhea, remains scarce. Thus, this review summarises current knowledge on the beneficial effects of green tea catechins on selected female reproductive disorders. Green tea or its derivative, EGCG, improves endometriosis mainly through anti-angiogenic, anti-fibrotic, anti-proliferative and proapoptotic mechanisms. Moreover, green tea enhances ovulation and reduces cyst formation in PCOS while improving generalised hyperalgesia, and reduces plasma corticosterone levels and uterine contractility in dysmenorrhea. However, information on clinical trials is inadequate for translating excellent findings on green tea benefits in animal endometriosis models. Thus, future clinical intervention studies are needed to provide clear evidence of the green tea benefits with regard to these diseases.
    Matched MeSH terms: Tea
  19. Warfarin and food, herbal or dietary supplement interactions: A systematic review
    Tan CSS, Lee SWH
    Br J Clin Pharmacol, 2021 02;87(2):352-374.
    PMID: 32478963 DOI: 10.1111/bcp.14404
    AIMS: To present an updated overview on the safety of concurrent use of food, herbal or dietary supplement and warfarin.

    METHODS: A systematic literature review was performed on 5 databases from inception up to 31 December 2019. These interactions were classified depending on the likelihood of interaction and supporting evidences.

    RESULTS: A total of 149 articles describing 78 herbs, food or dietary supplements were reported to interact with warfarin. These reports described potentiation with 45 (57.7%) herbs, food or dietary supplements while 23 (29.5%) reported inhibition and 10 (12.8%) reported limited impact on warfarin pharmacokinetics and pharmacodynamics. Twenty unique herb and dietary supplements also reported to result in minor bleeding events, such as purpura and gum bleeding as well as major events such as intracranial bleeding that led to death.

    CONCLUSION: While most food, herbs and supplements can be safely taken in moderation, healthcare professionals should be aware of the increased risk of bleeding when taking several food and herbs. These include Chinese wolfberry, chamomile tea, cannabis, cranberry, chitosan, green tea, Ginkgo biloba, ginger, spinach, St. John's Wort, sushi and smoking tobacco. Patients should be counselled to continue to seek advice from their healthcare professionals when starting any new herbs, food or supplement.

    Matched MeSH terms: Tea
  20. Fulltext Field demonstration of irradiated sodium alginate as tea production booster
    Hossain MA, Islam JMM, Hoque MM, Nahar S, Khan MA
    Heliyon, 2021 Jan;7(1):e05881.
    PMID: 33458447 DOI: 10.1016/j.heliyon.2020.e05881
    Sodium alginate oligomers were tested for tea plant growth promoter and anti-fungal agent in this experiment. Sodium alginate solutions were irradiated by Co-60 gamma radiation with different radiation doses to produce the oligomers. Irradiated solutions were then diluted into 150, 300 and 500 ppm prior to foliar application. Solutions were applied through foliar spraying at 7 days interval and the best response of tea plants in terms of various attributes were recorded. Tea buds were collected in 10 days of interval and the growth attributes like- total number of buds, fresh weight of buds, average leaf area and weight per bud, weight of made tea etc. were calculated. The experiment was continued up to 12 weeks and the attributes were averaged to get results per plucking. 12 kGy radiation doses along with 300ppm solution showed the best results and about 36% increase in productivity was found based on the fresh weight of buds. Total fungal count in tea leaves was also found to be reduced greatly. Based on the present study, irradiated sodium alginate could be used as safe and environmentally friendly agent to increase tea production.
    Matched MeSH terms: Tea
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