World Tea News 网站
Kenya’s massive and methodical tea industry is under stress as forces of nature combine with human nature to reduce exports. Precipitation during the country’s “long rains” season from March to May is well below the long-term average, leading forecasters to predict dry conditions that will result in food scarcity and water shortages. Meteorologists say that tropical cyclone Idai, a storm that killed thousands across East Africa, redirected moisture away from the region putting 1.1 million Kenyans in jeopardy.Tea production is down by half since the beginning of the season. The only bright spot are tensions between Pakistan and India that virtually halted exports between the two sabre-rattling countries. Sales picked up after India refused to sell tea to Pakistan, the world’s second largest tea importing country. Pakistan imports 70 million kilograms of Kenyan tea annually and is now the biggest buyer of Kenyan teas, paying $500 million in 2018, according to The East African.
World Tea News 网站
[学术文献] Human cancer stem cells are a target for cancer prevention using (−)-epigallocatechin gallate 进入全文
Journal of Cancer Research and Clinical Oncology 期刊
Purpose： Our previous experiments show that the main constituent of green-tea catechins, (−)-epigallocatechin gallate (EGCG), completely prevents tumor promotion on mouse skin initiated with 7,12-dimethylbenz(a)anthracene followed by okadaic acid and that EGCG and green tea extract prevent cancer development in a wide range of target organs in rodents. Therefore, we focused our attention on human cancer stem cells (CSCs) as targets of cancer prevention and treatment with EGCG. Methods The numerous reports concerning anticancer activity of EGCG against human CSCs enriched from cancer cell lines were gathered from a search of PubMed, and we hope our review of the literatures will provide a broad selection for the effects of EGCG on various human CSCs. Results Based on our theoretical study, we discuss the findings as follows: (1) Compared with the parental cells, human CSCs express increased levels of the stemness markers Nanog, Oct4, Sox2, CD44, CD133, as well as the EMT markers, Twist, Snail, vimentin, and also aldehyde dehydrogenase. They showed decreased levels of E-cadherin and cyclin D1. (2) EGCG inhibits the transcription and translation of genes encoding stemness markers, indicating that EGCG generally inhibits the self-renewal of CSCs. (3) EGCG inhibits the expression of the epithelial-mesenchymal transition phenotypes of human CSCs. (4) The inhibition of EGCG of the stemness of CSCs was weaker compared with parental cells. (5) The weak inhibitory activity of EGCG increased synergistically in combination with anticancer drugs. Conclusions Green tea prevents human cancer, and the combination of EGCG and anticancer drugs confers cancer treatment with tissue-agnostic efficacy.
[学术文献] Down-regulation of histone deacetylase 4, −5 and −6 as a mechanism of synergistic enhancement of apoptosis in human lung cancer cells treated with the combination of a synthetic retinoid, Am80 and green tea catechin 进入全文
The Journal of Nutritional Biochemistry 期刊
(−)-Epigallocatechin gallate (EGCG), a green tea catechin, acts as a synergist with various anticancer drugs, including retinoids. Am80 is a synthetic retinoid with a different structure from all-trans-retinoic acid: Am80 is now clinically utilized as a new drug for relapsed and intractable acute promyelocytic leukemia patients. Our experiments showed that the combination of EGCG and Am80 synergistically induced both apoptosis in human lung cancer cell line PC-9 and up-regulated expressions of growth arrest and DNA damage-inducible gene 153 (GADD153), death receptor 5, and p21waf1 genes in the cells. To understand the mechanisms of synergistic anticancer activity of the combination, we gave special attention to the lysine acetylation of proteins. Proteomic analysis using nanoLC-ESI-MS/MS revealed that PC-9 cells treated with the combination contained 331 acetylated proteins, while nontreated cells contained 553 acetylated proteins, and 59 acetylated proteins were found in both groups. Among them, the combination increased acetylated-p53 and acetylated-α-tubulin through reduction of histone deacetylase (HDAC) activity in cytosolfraction, although the levels of acetylation in histones H3 or H4 did not change, and the combination reduced protein levels of HDAC4, −5 and −6 by 20% to 80%. Moreover, we found that a specific inhibitor of HDAC4 and −5 strongly induced p21waf1 gene expression, and that of HDAC6 induced both GADD153 and p21waf1 gene expression, which resulted in apoptosis. All results demonstrate that EGCG in combination with Am80 changes levels of acetylation in nonhistone proteins via down-regulation of HDAC4, −5 and −6 and stimulates apoptotic induction.
Encyclopedia of Food and Health 图书
Bioavailability aims to describe the effect of metabolic events on nutrient utilization. The supply of nutrients to the human body depends not only on the amount of a nutrient in food but also on its bioavailability. The bioavailability of nutrients is highly variable and can be influenced by numerous factors. Different nutrients (including protein, iron, and vitamin A), and the forms in which they exist in the ingested medium, will react in different ways to inhibitors and enhancers as well as the host's nutritional status, all of which contribute to nutrient bioavailability.
Biochemical and Biophysical Research Communications 期刊
Cell motility and cell stiffness are closely related to metastatic activity of cancer cells. (−)-Epigallocatechin gallate (EGCG) has been shown to inhibit spontaneous metastasis of melanoma cell line into the lungs of mice, so we studied the effects of EGCG on cell motility, cell stiffness, and expression of vimentin and Slug, which are molecular phenotypes of epithelial–mesenchymal transition (EMT). Treatments of human non-small cell lung cancer cell lines H1299 and Lu99 with 50 and 100 μM EGCG reduced cell motility to 67.5% and 43.7% in H1299, and 71.7% and 31.5% in Lu99, respectively in in vitro wound healing assay. Studies on cell stiffness using atomic force microscope (AFM) revealed that treatment with 50 μM EGCG increased Young’s modulus of H1299 from 1.24 to 2.25 kPa and that of Lu99 from 1.29 to 2.28 kPa, showing a 2-fold increase in cell stiffness, i.e. rigid elasticity of cell membrane. Furthermore, treatment with 50 μM EGCG inhibited high expression of vimentin and Slug in the cells at a leading edge of scratch. Methyl-β-cyclodextrin, a reagent to deplete cholesterol in plasma membrane, showed inhibition of EMT phenotypes similar that by EGCG, suggesting that EGCG induces inhibition of EMT phenotypes by alteration of membrane organization.