scholarly journals Health Benefits of Aqueous Extract of Black and Green Tea Leaves

2020 ◽  
Author(s):  
Zainab Khudhur Ahmad Al-Mahdi ◽  
Ruqaya M.J. Ewadh ◽  
Nada Khazal Kadhim Hindi

Tea, next to water, is the beverage humans consume. Drinking the beverage tea is great for joining and collecting family members and public communities since ancient times. Tea plant Camellia sinensis has been cultivated for thousands of years, and its leaves have been used for medicinal purposes. Various studies suggest that polyphenolic compounds present in green and black tea are associated with beneficial effects in prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease. Anti-ageing, antidiabetic and many other health beneficial effects associated with tea consumption are described. Evidence is accumulating that catechins and theaflavins, which are the main polyphenolic compounds of green and black tea, respectively, are responsible for most of the physiological effects of tea. This review describes the evidence from clinical and epidemiological studies in the prevention of chronic diseases like cancer and cardiovascular diseases and inhibits pathogenic bacteria and general health promotion associated with tea consumption.

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1862 ◽  
Author(s):  
Nenad Naumovski ◽  
Alexandra Foscolou ◽  
Nathan M. D’Cunha ◽  
Stefanos Tyrovolas ◽  
Christina Chrysohoou ◽  
...  

Tea is one of the most-widely consumed beverages in the world with a number of different beneficial health effects, mainly ascribed to the polyphenolic content of the tea catechins. The aim of this study was to examine the consumption of green, black, or no tea, in relation to the previously validated successful ageing index (SAI; higher values “healthier” ageing) in a combined analysis of adults aged >50 years old from the ATTICA (n = 1128 adults from Athens, Greece metropolitan area) and the MEDiterranean Islands Study (MEDIS) (n = 2221 adults from various Greek island and Mani) studies. After adjusting for age, sex, smoking, and coffee consumption, green tea was positively associated with SAI (b ± SE: 0.225 ± 0.055, p < 0.001), while black tea was negatively associated with SAI (unstandardized b coefficient ± Standard error: −0.807 ± 0.054, p < 0.001). Green tea (vs black tea) consumption, had higher odds of a SAI of over 3.58 out of 10 (OR: 1.77, 95% CI: 1.38–2.28). Green tea consumption was also associated with higher levels of physical activity (p < 0.001) and reduced likelihood of hypertension (p = 0.006) compared with black tea. Two possible mechanisms are that green tea possesses high levels of catechins such as (−)-epigallocatechin 3-gallate and l-theanine compared with black tea. Therefore, the present analysis supports both the role of green tea constituents in successful ageing, as well as its role as an important component of an overall healthy diet in adults aged 50 years and over from these two epidemiological studies.


Nutrients ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 39 ◽  
Author(s):  
Naghma Khan ◽  
Hasan Mukhtar

Tea is the most widely used beverage worldwide. Japanese and Chinese people have been drinking tea for centuries and in Asia, it is the most consumed beverage besides water. It is a rich source of pharmacologically active molecules which have been implicated to provide diverse health benefits. The three major forms of tea are green, black and oolong tea based on the degree of fermentation. The composition of tea differs with the species, season, leaves, climate, and horticultural practices. Polyphenols are the major active compounds present in teas. The catechins are the major polyphenolic compounds in green tea, which include epigallocatechin-3-gallate (EGCG), epigallocatechin, epicatechin-3-gallate and epicatechin, gallocatechins and gallocatechin gallate. EGCG is the predominant and most studied catechin in green tea. There are numerous evidences from cell culture and animal studies that tea polyphenols have beneficial effects against several pathological diseases including cancer, diabetes and cardiovascular diseases. The polyphenolic compounds present in black tea include theaflavins and thearubigins. In this review article, we will summarize recent studies documenting the role of tea polyphenols in the prevention of cancer, diabetes, cardiovascular and neurological diseases.


Stroke ◽  
2009 ◽  
Vol 40 (5) ◽  
pp. 1786-1792 ◽  
Author(s):  
Lenore Arab ◽  
Weiqing Liu ◽  
David Elashoff

1845 ◽  
Vol 1 ◽  
pp. 381-382

An examination of these specimens seemed to prove, that the leaves of the China tea-plant, cultivated at the same plantation with the tea-plant of Assam, are considerably less, and somewhat thicker, but otherwise so exactly similar, that the two plants may well be mere varieties of the same species,—an opinion now generally adopted by botanists in India. The specimens further illustrated the doctrine deduced from recent investigations in India, that the different kinds of green and black tea are made from the leaves of one species of plant, collected at different periods of their development.


2007 ◽  
Vol 99 (4) ◽  
pp. 863-868 ◽  
Author(s):  
Nicoline Jochmann ◽  
Mario Lorenz ◽  
Amélie von Krosigk ◽  
Peter Martus ◽  
Volker Böhm ◽  
...  

Consumption of tea has been shown to improve endothelial function. It is assumed that catechins are the tea components responsible for these beneficial effects. In black tea, catechin concentrations are significantly lower than in green tea. The present study was designed to compare green and black tea with regard to amelioration of endothelial function. Endothelial function in response to both teas was assessed in bovine aortic endothelial cells (BAEC) and rat aortic rings. To elucidate whether these findings are also applicable to humans, flow-mediated dilation (FMD) and nitro-mediated dilation (NMD) were assessed by ultrasound in twenty-one healthy women before and 2 h after consumption of green and black tea (2 h of FMD and NMD), in comparison with water (control). In BAEC, green and black tea significantly increased endothelial NO synthase activity to the same extent. Similarly, both teas induced comparable endothelial-dependent vasodilation in rat aortic rings. In human subjects, ingestion of green and black tea led to significant increases in FMD: from 5·4 (sd 2·3) to 10·2 (sd 3) % (baseline-adjusted difference (BAD) for 2 h of FMD, green tea v. water: 5·0 (95 % CI 3·0, 7·0) %; P < 0·001) and from 5 (sd 2·6) to 9·1 (sd 3·6) % (BAD for 2 h of FMD, black tea v. water: 4·4 (95 % CI 2·3, 6·5) %; P < 0·001), respectively. The increase in FMD was not significantly different between the two tea preparations (BAD for 2 h of FMD, green tea v. black tea: 0·66 (95 % CI − 0·76, 2·09) %; P = 0·36). NMD did not vary between any of the groups. In conclusion, green and black tea are equally effective in improving endothelial function.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 415
Author(s):  
Ryuuta Fukutomi ◽  
Tomokazu Ohishi ◽  
Yu Koyama ◽  
Monira Pervin ◽  
Yoriyuki Nakamura ◽  
...  

Many observational and clinical studies have shown that consumption of diets rich in plant polyphenols have beneficial effects on various diseases such as cancer, obesity, diabetes, cardiovascular diseases, and neurodegenerative diseases (NDDs). Animal and cellular studies have indicated that these polyphenolic compounds contribute to such effects. The representative polyphenols are epigallocatechin-3-O-gallate in tea, chlorogenic acids in coffee, resveratrol in wine, and curcumin in curry. The results of human studies have suggested the beneficial effects of consumption of these foods on NDDs including Alzheimer’s and Parkinson’s diseases, and cellular animal experiments have provided molecular basis to indicate contribution of these representative polyphenols to these effects. This article provides updated information on the effects of these foods and their polyphenols on NDDs with discussions on mechanistic aspects of their actions mainly based on the findings derived from basic experiments.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Dan-Dan Zhou ◽  
Min Luo ◽  
Ao Shang ◽  
Qian-Qian Mao ◽  
Bang-Yan Li ◽  
...  

Cardiovascular diseases (CVDs) have gained increasing attention because of their high prevalence and mortality worldwide. Epidemiological studies revealed that intake of fruits, vegetables, nuts, and cereals could reduce the risk of CVDs, and their antioxidants are considered as the main contributors. Moreover, experimental studies showed that some antioxidant natural products and their bioactive compounds exerted beneficial effects on the cardiovascular system, such as polyphenols, polysaccharides, anthocyanins, epigallocatechin gallate, quercetin, rutin, and puerarin. The mechanisms of action mainly included reducing blood pressure, improving lipid profile, ameliorating oxidative stress, mitigating inflammation, and regulating gut microbiota. Furthermore, clinical trials confirmed the cardiovascular-protective effect of some antioxidant natural products, such as soursop, beetroot, garlic, almond, and green tea. In this review, we summarized the effects of some antioxidant natural products and their bioactive compounds on CVDs based on the epidemiological, experimental, and clinical studies, with special attention paid to the relevant mechanisms and clinical trials.


2021 ◽  
Vol 24 (3) ◽  
Author(s):  
Masoomeh Shirzaiy ◽  
Zohreh Dalirsani ◽  
Javid Dehghan Haghighi

Background: Some herbal products could affect on salivary pH and prevention of dental caries. Tea consumption has inhibition effects on some oral bacteria. Objective: The aim of this study was to evaluate the effect of green and black tea on salivary pH. Material and Methods: In this double blinded cross-over trial, salivary samples of 50 healthy male students of Zahedan Faculty of Dentistry, aged 20-22 years old were collected for evaluation of salivary pH. All volunteers were asked to consume commercially black tea on the first day and then saliva samples were collected before drinking tea and immediately after drinking tea and 5 and 10 minutes after tea consumption. With replacing consumption of green tea, at the second day, saliva samples were collected again. Then the salivary pH was estimated with a digital pH-meter. Data were analyzed through independent t-test and paired samples t-test. Results: Mean salivary pH before and after green tea consumption were 7.15±0.05 and 7.56±0.09, respectively, which showed a remarkable difference (p<0.001). It was 7.14±0.05 and 7.51 ± 0.10, respectively, for black tea, with significant difference (p<0.0001). Mean salivary pH after green tea consumption was significantly higher than black tea (p= 0.006). Conclusion: Both green and black tea intake led to a significant rise in salivary pH, which was higher after green tea consumption compared to black tea. This study suggests the beneficial effects of drinking tea in providing an alkaline environment in oral cavity.   KEYWORDS Black tea; Green tea; Saliva; pH.


Author(s):  
Baolu Zhao

Tea is the most frequently consumed beverage worldwide besides water. Generally, there are five most popular types of tea: green, white, black, Pu’er, and oolong. Tea possesses significant antioxidant, anti-inflammatory, antimicrobial, anticarcinogenic, antihypertensive, neuroprotective, and cholesterol-lowering properties. Several research investigations, epidemiological studies, and meta-analyses suggest that tea and its bioactive polyphenolic constituents have numerous beneficial effects on health, including the prevention of many diseases, such as cancer, diabetes, arthritis, cardiovascular disease, stroke, and obesity. Recently, there are many reports about the resistance of tea to COVID-19 virus on the Internet, which has attracted a lot of attention to tea drinking and the discussion about the pros and cons of tea drinking. Based on our research results and relevant reports form literatures, this review is intended to highlight the beneficial effects and possible side-effects associated with tea consumption, answer 10 questions and point out a few matters for attention.


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