immunity
Recent Research Papers on
immunity
Author: Chwan-Li Shen and James K. Yeh and Jay J. Cao and Jia-Sheng Wang
Osteoporosis is a major health problem in both elderly women and men. Epidemiological evidence has shown an association between tea consumption and the prevention of age-related bone loss in elderly women and men. Ingestion of green tea and green tea bioactive compounds may be beneficial in mitigating bone loss of this population and decreasing their risk of osteoporotic fractures. This review describes the effect of green tea or its bioactive components on bone health, with an emphasis on (i) the prevalence and etiology of osteoporosis; (ii) the role of oxidative stress and antioxidants in osteoporosis; (iii) green tea composition and bioavailability; (iv) the effects of green tea and its active components on osteogenesis, osteoblastogenesis, and osteoclastogenesis from human epidemiological, animal, as well as cell culture studies; (v) possible mechanisms explaining the osteoprotective effects of green tea bioactive compounds; (vi) other bioactive components in tea that benefit bone health; and (vii) a summary and future direction of green tea and bone health research and the translational aspects. In general, tea and its bioactive components might decrease the risk of fracture by improving bone mineral density and supporting osteoblastic activities while suppressing osteoclastic activities.
Author: Rashmi Singh and Nahid Akhtar and Tariq M. Haqqi
A number of factors including inflammation and oxidative stress are believed to play a role in the development of chronic joint diseases. Green tea has become a popular drink and is consumed throughout the world. Extracts of green tea and polyphenols present therein have been shown to inhibit the inflammatory responses in vitro in different cell types and the development of arthritis in animal model studies. There is considerable evidence that (−)-epigallocatechin-3-gallate (EGCG), the predominant green tea polyphenol which mimic its effects, inhibits enzyme activities and signal transduction pathways that play important roles in inflammation and joint destruction in arthritis. After oral consumption EGCG become bioavailable and proteomic studies suggest that EGCG may directly interact with a large set of protein targets and alter the physiological response of the cells. Taken together these and other studies identify and support the use of EGCG as a possible chemopreventive agent with a potential to inhibit the development of arthritis. Here we review the biological effects of EGCG in an attempt to understand its pivotal molecular targets that directly affect the inflammation and joint destruction process for prevention and/or for the development of new therapeutics for arthritis in humans.
Author: Jonathan M. Hodgson and Kevin D. Croft
The two main types of tea are green and black. Both green and black teas are rich dietary sources of flavonoids. Available evidence suggests that regular tea consumption may reduce the risk of cardiovascular disease. The cardiovascular health benefits of drinking tea are thought to be largely due to flavonoids. Tea intake and intake of flavonoids found in tea have been associated with reduced risk of cardiovascular disease in cross-sectional and prospective population studies. Isolated flavonoids found in tea have also been consistently shown to inhibit the development of atherosclerosis in animal models. A number of possible pathways and mechanisms have been investigated. There is now consistent data indicating that tea and tea flavonoids can enhance nitric oxide status and improve endothelial function, which may be at least partly responsible for benefits on cardiovascular health. There is also evidence, although limited, to suggest benefits of green tea (flavonoids) on body weight and body fatness. Data supporting reduced oxidative damage, inflammation, platelet activation, blood pressure, and risk of type 2 diabetes with tea (flavonoids) remains inadequate to draw any conclusions.
Author: Hajime Fujii and Hiroshi Nishioka and Koji Wakame and Bernadene A. Magnuson and Ashley Roberts
Oligonol is a phenolic product derived from lychee fruit extract and green tea extract, containing catechin-type monomers and oligomers of proanthocyanidins, produced by a manufacturing process which converts polyphenol polymers into oligomers. The safety of Oligonol was assessed in acute and subchronic studies and genotoxicity assays. In a single dose acute study of Oligonol, male and female rats were administered 2000mg/kg body weight (bw) Oligonol in water by gavage. Oligonol caused no adverse effects and body weight gain and food consumption were within normal range, thus the LD(50) of Oligonol was determined to be greater than 2000mg/kg. A 90 day subchronic study (100, 300 and 1000mg/kgbw/day, oral gavage) in male and female rats reported no significant adverse effects in food consumption, body weight, mortality, clinical chemistry, haematology, gross pathology and histopathology. Similarly, no adverse effects were observed in mice fed diets providing 2, 20 or 200mg/kgbw Oligonol or 200mg/kgbw lychee polyphenol for 90 days. Oligonol did not show any potential to induce gene mutations in reverse mutation tests using Salmonella typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2uvrA strains. Oligonol did not induce chromosomal aberrations in cultured Chinese hamster lung cells, but it showed increased polyploidy. In a micronucleus assay in mice, Oligonol did not induce any micronuclei or suppress bone marrow, indicating it does not cause chromosome aberrations. The results from these safety studies and previous reports support the safety of Oligonol for human consumption.
Author: Radomir V. Malbaša and Eva S. Lončar and Jasmina S. Vitas and Jasna M. Čanadanović-Brunet
This paper investigates the influence of starter cultures, obtained from kombucha isolates, on the antioxidant activity of kombucha beverages. Three starter cultures were used as follows: (1) mixed culture of acetic bacteria and Zygosaccharomyces sp. (SC1); (2) mixed culture of acetic bacteria and Saccharomyces cerevisiae (SC2); as well as (3) native local kombucha. The starter cultures were added to black and green tea sweetened with 7% of sucrose. Fermentation was carried out at 28 °C for 10 days. Antioxidant activity to hydroxyl and DPPH radicals was monitored. Kombucha beverage on black tea has shown the highest antioxidant activity to both types of radicals with starter SC1, while the green tea beverage has shown the highest activity with native kombucha. The main reason for the different antioxidant activities, beside tea composition, was ascribed to differing production of both vitamin C and total organic acids in the investigated systems.
Author: Atsuo Miyagishima and Sadahiro Fujiki and Aya Okimura and Sakae Arahata and Shinsuke Inagaki and Yasunori Iwao and Shigeru Itai
We have recently succeeded in manufacturing low-caffeine tea (LCT) by employing a special picking method in the 3rd leaf period and shortening the leaf-rolling process. In the present study, the effect of this special method on the content of other physiologically active substances, such as catechins, theanine, and vitamin C, as well as the mechanism of reduction of caffeine content in the LCT were investigated using capillary electrophoresis. By comparing the various components of tea leaves at different picking periods with or without shortening of the rolling process, it was found that the delayed leaf picking period and shortening of the rolling process used in the manufacture of LCT selectively reduced the caffeine content while retaining catechins, theanine, and vitamin C at a sufficient level. Therefore, our study demonstrated that this modified method may be useful in the manufacture of decaffeinated green tea.
Author: Anna Hsu and Richard S. Bruno and Christiane V. Löhr and Alan W. Taylor and Rodrick H. Dashwood and Tammy M. Bray and Emily Ho
Chronic inflammation and nuclear factor-kappa B (NFκB) have been implicated in prostate cancer development; thus, dietary factors that inhibit NFκB may serve as effective chemo-preventative agents. Prostate cancer risk is significantly lower in Asian countries compared to the United States, which has prompted interest in the potential chemopreventative action of Asian dietary components such as soy and green tea. This study examined the effects of dietary soy and tea on NFκB activation and inflammation in vivo using a hormone-induced rat model for prostate cancer. Male Noble rats implanted with estradiol and testosterone were divided into 4 dietary groups: control, soy, tea, or soy+tea. NFκB activation and inflammatory cytokines were measured post implantation. The combination of soy and tea suppressed NFκB p50 binding activity and protein levels via induction of IκBα. Soy and tea also decreased prostate inflammatory infiltration, increased Bax/BcL2 ratio and decreased protein expression of tumor necrosis factor-alpha, interleukin (IL)-6 and IL-1β compared to control. Soy and tea attenuated prostate malignancy by decreasing prostate hyperplasia. These effects were not apparent in groups treated with soy or tea alone. The ongoing in vivo studies thus far suggest that combination of foods, such as soy and tea, may inhibit hormone-induced proinflammatory NFκB signals that contribute to prostate cancer development.
Author: Alaa El-Din A. Bekhit and Vern Jou Cheng and Michelle McConnell and Jenny H. Zhao and Richard Sedcole and Roland Harrison
Grape skin extracts from pinot noir and pinot gris exhibited significant in vitroantiviral (influenza virus) activity. Five tea infusions from grape skins (Vitis vinifera var. pinot noir and pinot gris) without any additives (control pinot noir and control pinot gris) or by adding variable amounts of green tea and hibiscus were investigated as a means to utilise wine wastes. The antioxidant activities (DPPHscavenging capacity and superoxide anion radical scavenging capacity), total phenolics, the polyphenolics profile and objective colour measurements (CIELab) were determined on freeze-dried water extracts of all five tea infusions, hibiscus and green tea. The colour parameters, L∗ and a∗ values, varied widely (P < 0.05) for all the infusions as a result of having different levels and variety of pigments. The tea infusions exhibited weak antioxidant activity and the antiviral activity in grape skin appears not related to phenolics contents.
Author: Ramasamy Harikrishnan and Chellam Balasundaram and Moon-Soo Heo
Effect of diet enriched with green tea at 0, 0.01, 0.1 or 1.0% levels on immune responses such as non-specific humoral (lysozyme, antiprotease and complement) and cellular (myeloperoxidase content, production of reactive oxygen, and nitrogen species) and disease resistance on week 1, 2 or 4 in kelp grouper Epinephelus bruneus challenged with Vibrio carchariae(2.47 × 108 CFU ml−1) was quantified. At all doses green tea supplementation significantly enhanced the serum lysozyme activity from weeks 1 to 4. On the other hand, after week 2 the serum hemolytic complement activity, leucocyte myeloperoxidase content and reactive nitrogen species protection significantly increased in groups fed with 0.01 and 0.1% green tea supplementation diets. The serum antiprotease activity significantly increased in group fed with at 1.0% green tea from week 1 to 4. However, all diets except at 0.01% level resulted in a significant decrease in reactive oxygen species protection during the experimental period. Challenged groups fed with green tea enriched diet at 0.01 and 0.1% level had a higher relative percent survival than with 1.0% diet on week 1, 2 or 4. The results suggest that dietary administration of green tea supplementation at a concentration of 0.01 and 0.1% level positively enhances the non-specific humoral and cellular immune responses and disease resistance of kelp grouper E. bruneus to V. carchariae.
Author: Raul Dominguez-Perles and Diego A. Moreno and Micaela Carvajal and Cristina Garcia-Viguera
Organic green tea, one of the most-consumed beverages worldwide, is rich in bioactive compounds (flavonols and flavanols) with healthy properties. Broccoli byproducts, consisting of leaves and stalks, are rich in bioactive compounds, including nitrogen–sulphur compounds (glucosinolates and isothiocyanates) and phenolics (chlorogenic and sinapic acid derivatives, and flavonoids), as well as essential nutrients (minerals and vitamins). They are of high interest as a source of health-promoting compounds, useful as ingredients for the development of functional foods. This work analyses minimally-processed broccoli byproducts as a source of bioactive ingredients to design novel beverages, using organic green tea as a food matrix. Green tea enriched with broccoli concentrates showed improved physical quality, phytochemical composition and antioxidant capacity. The functional quality of these novel beverages depends on the proportion of broccoli extracts added to the green tea. The results obtained in the present work should encourage the use of broccoli byproducts as ingredients in novel functional foods. Industrial relevance The industrial use of broccoli byproducts as an ingredient in the development of novel, functional foods may help to add value to the large amount of plant wastes generated in every cropping season, thus reducing their environmental impact. The objectives and aims of the EU producers, industry and stakeholders on the relationships between foods, nutrition and health, and therefore, the use of suitable ingredients from the agriculture to have impact on human health and the environment, with a sustainable use of natural resources are in agreement with this work, adding value to broccoli byproducts and encouraging the production of novel products and applications for nutritional and/or health claims under the EU Regulations (EC) No. 1924/2006 and 834/2007.