Effect of different doses of un-fractionated green and black tea extracts on thyroid physiology

Tea is a rich source of polyphenolic flavonoids including catechins, which are thought to contribute to the health benefits of it. Flavonoids have been reported to have antithyroid and goitrogenic effect. The purpose of this study was to evaluate whether high doses of green and black tea have a harmful effect on thyroid physiology. Un-fractionated green and black tea extracts were administered orally to male rats for 30 days at doses of 1.25 g%, 2.5 g% and 5.0 g%. The results showed that green tea extract at 2.5 g% and 5.0 g% doses and black tea extract only at 5.0 g% dose have the potential to alter the thyroid gland physiology and architecture, that is, enlargement of thyroid gland as well as hypertrophy and/or hyperplasia of the thyroid follicles and inhibition of the activity of thyroid peroxidase and 5′-deiodinase I with elevated thyroidal Na+, K+-ATPase activity along with significant decrease in serum T3 and T4, and a parallel increase in serum thyroid stimulating hormone (TSH). This study concludes that goitrogenic/antithyroidal potential of un-fractionated green tea extract is much more than black tea extract because of the differences in catechin contents in the tea extracts.

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Uji Pendahuluan Anti-biofilm Esktrak Teh Hijau dan Teh Hitam Pada Streptococcus mutans melalui Metode Microtiter Plate

Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) ◽

10.22487/j24428744.2018.v4.i1.9965 ◽

2018 ◽

Vol 4 (1) ◽

pp. 44-49

Author(s):

Andi Arjuna ◽

Winda Setya Pratama ◽

Sartini Sartini ◽

Mufidah Mufidah

Keyword(s):

Streptococcus Mutans ◽

Green Tea ◽

Black Tea ◽

Microtiter Plate ◽

Green Tea Extract ◽

Biofilm Growth ◽

Microtiter Plate Assay ◽

Black Tea Extract ◽

Green And Black Tea ◽

Tea Extract

Tea (Camellia sinensis L.) has an activity as an antibacterial, widely studied to plankton cells, without further researching into biofilm cell. Therefore, this research had been conducted to initially evaluate the activity of green- and black-tea extracts in inhibiting Streptococcus mutans biofilm. Green and black tea leaves were extracted using 70% methanol. Determination of MIC was subsequently performed by microdilution method. Next, the biofilm formation and inhibition were run through microtiter plate method using flexible U-bottom PVC 96 wells, which then observed using microplate reader on λ = 515 nm. As The results, MIC for green and black tea extract stood at 4 mg/mL, 6 mg/mL respectively. The biofilm inhibitory activity of black tea extract was at 8 and 10 mg/mL inhibiting 6 % and 12.5 % S. mutans. Green tea extract showed that concentration of 4 to 10 mg/mL was able to inhibit biofilm growth by 24%; 45%; 48% and 53%. Thus, through microtiter plate assay, it could be concluded that tea extract has potent antibiofilm to S. mutans, where green tea extract has better activity than black tea extract.

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Black tea increases hypertonic stress resistance in C. elegans

Food & Function ◽

10.1039/c7fo02017a ◽

2018 ◽

Vol 9 (7) ◽

pp. 3798-3806 ◽

Cited By ~ 5

Author(s):

Pei Yuan ◽

Lian-yun Pan ◽

Li-gui Xiong ◽

Jie-wen Tong ◽

Juan Li ◽

...

Keyword(s):

Green Tea ◽

Stress Resistance ◽

Black Tea ◽

Green Tea Extract ◽

Hypertonic Stress ◽

C Elegans ◽

Black Tea Extract ◽

Tea Extract

Black tea extract is more effective than green tea extract in protecting C. elegans against hypertonic stress, within the studied concentration range.

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Goitrogenic and Antithyroid Potential of Green Tea of Indian Origin

Journal of Bangladesh Society of Physiologist ◽

10.3329/jbsp.v9i2.22807 ◽

2015 ◽

Vol 9 (2) ◽

pp. 105-116 ◽

Cited By ~ 2

Author(s):

Amar K Chandra ◽

Neela De

Keyword(s):

Green Tea ◽

Green Tea Extract ◽

Male Rats ◽

Albino Rats ◽

Thyroid Peroxidase ◽

Functional Changes ◽

Indian Origin ◽

Regular Consumption ◽

High Doses ◽

Tea Extract

Polyphenolic flavonoids, specially catechins are major constituents of tea. Antithyroidal and goitrogenic effect of flavonoids have been reported however such effects of green tea on thyroid physiology has not been explored earlier. Green tea is derived from the tea leaves of Camellia sinensis and widely consumed globally. The green tea extracts(GTE) at different concentrations (1.25g% a 5 cups of tea/ day; 2.5g% a 10 cups of tea/ day and 5.0g% a 20 cups of tea/ day) were orally fed to male rats for 30 days. Similarly, pure catechin was administered orally to male albino rats for 30 days at doses of 25, 50 and 100 mg/kg body weight that are equivalent to above doses of green tea extract in terms of its total catechin content and the morphological and functional changes of the thyroid have been investigated. The overall results reveal that oral administration of green tea extract at 2.5g% and 5.0g% concentrations for 30 days changed the morphology and histology resembling hypertrophy of thyroid follicles with differential colloid sizes as found in hypothyroid due to environment influences associated with significant inhibited activities of thyroid peroxidase(TPO) and 5 monodeiodinase (5 DI1) with elevated Na+,K+ ATPase and concomitant decrease in serum thyroxine (T4), triiodothyronine (T3) and increase in serum thyrotropin (TSH) levels developing a state of absolute biochemical hypothyroidism. All these suggest that catechin present in green tea has the antithyroidal as well as goitrogenic potential and its regular consumption at relatively high doses pose a threat to the functioning of thyroid. DOI: http://dx.doi.org/10.3329/jbsp.v9i2.22807 Bangladesh Soc Physiol. 2014, December; 9(2): 105-116

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Green tea extract and black tea extract differentially influence cecal levels of short-chain fatty acids in rats

Food Science & Nutrition ◽

10.1002/fsn3.607 ◽

2018 ◽

Vol 6 (4) ◽

pp. 728-735 ◽

Cited By ~ 8

Author(s):

Tomonori Unno ◽

Naomi Osakabe

Keyword(s):

Fatty Acids ◽

Green Tea ◽

Black Tea ◽

Short Chain Fatty Acids ◽

Green Tea Extract ◽

Short Chain ◽

Black Tea Extract ◽

Tea Extract ◽

Chain Fatty Acids

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Comparative Safety Evaluation of Chinese Pu-erh Green Tea Extract and Pu-erh Black Tea Extract in Wistar Rats

Journal of Agricultural and Food Chemistry ◽

10.1021/jf902171h ◽

2010 ◽

Vol 58 (2) ◽

pp. 1350-1358 ◽

Cited By ~ 36

Author(s):

Di Wang ◽

Rong Xiao ◽

Xueting Hu ◽

Kunlong Xu ◽

Yan Hou ◽

...

Keyword(s):

Green Tea ◽

Wistar Rats ◽

Safety Evaluation ◽

Black Tea ◽

Green Tea Extract ◽

Black Tea Extract ◽

Comparative Safety ◽

Tea Extract

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Protective effect of green tea extract against cadmium-induced testicular damage in rats in respect of oxidant/antioxidant equilibrium and androgen production

Mansoura Veterinary Medical Journal ◽

10.35943/mvmj.2020.21.105 ◽

2020 ◽

Vol 21 (1) ◽

pp. 31-35

Author(s):

Basma El-Desoky ◽

Shaimaa El-Sayed ◽

El-Said El-Said

Keyword(s):

Gene Expression ◽

Single Dose ◽

Green Tea ◽

Serum Testosterone ◽

Green Tea Extract ◽

Male Rats ◽

Controlled Study ◽

Control Group ◽

Testicular Damage ◽

Tea Extract

Objective: Investigating the effect of green tea extract (GTE) on the testicular damage induced by cadmium chloride CdCl2 in male rats. Design: Randomized controlled study. Animals: 40 male Wistar rats. Procedures: Rats were randomly divided into four groups: A) control group (each rat daily received pellet diet); B) GTE group each rat daily received pellet diet as well as 3 ml of 1.5 % w/v GTE, C) CdCl2 group each rat was I/P injected a single dose of 1 mg/kg CdCl2, then daily received pellet diet, and D) CdCl2+GTE group each rat was I/P injected a single dose of 1 mg/kg CdCl2 then daily received pellet diet as well as 3 ml of 1.5 % w/v GTE. After 30 days, blood samples were collected for hormonal assays (testosterone, FSH, and LH). In addition, both testes were collected; one of them was used for quantification of 17-beta hydroxysteroid dehydrogenase III (17β-HSDIII) gene expression using a real-time PCR. The other testis was used for determination of catalase and reduced glutathione; GSH, Nitric oxide (NO) and malondialdehyde (MDA) levels. Results: CdCl2 decreased serum testosterone levels and its synthesis pathway (17β-HSDIII testicular gene expression). While antioxidants catalase and GSH were reduced, oxidants MDA were enriched in the testes of CdCl2-poisoned rats. This CdCl2-promoted testicular dysfunction was corrected via the administration of GTE to male rats. Conclusion and clinical relevance: GTE could be used as a remedy for protecting against CdCl2-induced testicular damage in male rats.

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Efektivitas Ekstrak Teh Hijau (Camellia sinensis L.) terhadap Penurunan Kadar Glukosa Darah Puasa Tikus Wistar (Rattus norvegicus) yang diInduksi Aloksan

Jurnal Sehat Mandiri ◽

10.33761/jsm.v15i1.194 ◽

2020 ◽

Vol 15 (1) ◽

pp. 86-97

Author(s):

Hafshah . ◽

Kristina Simanjuntak

Keyword(s):

Green Tea ◽

Fasting Blood Glucose ◽

White Male ◽

Green Tea Extract ◽

Male Rats ◽

Test Results ◽

Male Wistar Rats ◽

Bonferroni Test ◽

Tea Extract ◽

Post Hoc

The sufferers of Diabetes Mellitus (DM) in Indonesia is the highest with fourth number in the world, with a mortality rate of 1.2 million in 2012. Because of it, DM research using antihyperglycemic green tea is needed. This study aims to determine the effectiveness of green tea extracts on decreasing fasting blood glucose (KGDP) levels in alloxan-induced white male Wistar rats. Samples were 30 male rats, aged 8-12 weeks, weight ± 200 grams. Rats were grouped into 6 groups with the first group (K1) as a control, the second group (K2) induced alloxan, the third group (K3) induced alloxan with glibenclamide, the fourth group (K4), the fifth group (K5), and the sixth group (K6) induced alloxan with green tea extract as the treatment with dose of green tea extract, 200 mg/kg, 400 mg/kg, and 800 mg/kg. The first, FBG level examination is done 3 days after induction of alloxan using a glucometer. Giving green tea extract was given for 16 days orally, then FBG level re-examined from the tail of rats. One Way ANOVA Test Results, there is the effectiveness of green tea extract on reducing FBG level (p = 0,000). The post hoc Bonferroni test showed that giving 800 mg/kg of green tea extract was the best dose in reducing KGDP close to normal (p = 0,000).

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