Therapeutic properties of green tea against environmental insults

Abstract

Pesticides, smoke, mycotoxins, polychlorinated biphenyls, and arsenic are the most common environmental toxins and toxicants to humans. These toxins and toxicants may impact on human health at the molecular (DNA, RNA, or protein), organelle (mitochondria, lysosome, or membranes), cellular (growth inhibition or cell death), tissue, organ, and systemic levels. Formation of reactive radicals, lipid peroxidation, inflammation, genotoxicity, hepatotoxicity, embryotoxicity, neurological alterations, apoptosis, and carcinogenic events are some of the mechanisms mediating the toxic effects of the environmental toxins and toxicants. Green tea, the non-oxidized and non-fermented form of tea that contains several polyphenols, including green tea catechins, exhibits protective effects against these environmental toxins and toxicants in preclinical studies and to a much-limited extent, in clinical trials. The protective effects are collectively mediated by antioxidant, anti-inflammatory, anti-mutagenic, hepato- and neuroprotective, and anti-carcinogenic activities. In addition, green tea modulates signaling pathway including NFκB and ERK pathways, preserves mitochondrial membrane potential, inhibits caspase-3 activity, down-regulates pro-apoptotic proteins, and induces the phase II detoxifying pathway. The bioavailability and metabolism of green tea and its protective effects against environmental insults induced by pesticides, smoke, mycotoxins, polychlorinated biphenyls, and arsenic are reviewed in this paper. Future studies with emphasis on clinical trials should identify biomarkers of green tea intake, examine the mechanisms of action of green tea polyphenols, and investigate potential interactions of green tea with other toxicant-modulating dietary factors.

Cosmetic Functional Ingredients from Botanical Sources for Anti-Pollution Skincare Products

“…Green tea is obtained by roasting or steaming Camellia sinensis (Theaceae) leaves in order to inactivate polyphenol oxidase activity. Green tea extracts are complex mixtures of bioactive compounds, including tea polyphenols, primarily green tea catechins, that account for 30-40% of the extractable solid of dried green tea leaves [78]. Tea catechins include epicatechin, epicatechin-3-gallate, epigallocatechin and epigallocatechin gallate [78].…”

“…Green tea extracts are complex mixtures of bioactive compounds, including tea polyphenols, primarily green tea catechins, that account for 30-40% of the extractable solid of dried green tea leaves [78]. Tea catechins include epicatechin, epicatechin-3-gallate, epigallocatechin and epigallocatechin gallate [78]. These polyphenols have gained interest in recent years because of interesting biological activities, including antimicrobial, anti-inflammatory, anticancer, antioxidant and radical scavenging activities [79][80][81][82].…”

“…These polyphenols have gained interest in recent years because of interesting biological activities, including antimicrobial, anti-inflammatory, anticancer, antioxidant and radical scavenging activities [79][80][81][82]. On the basis of their biological properties, green tea polyphenols are generally accepted as having a protective effect against oxidative stress and DNA and cell structures damage induced by a number of environmental toxins/toxicants (pesticides, smoking, mycotoxins, PCB, arsenic [78]); these properties provide the rationale for the use of green tea extracts as functional ingredients of anti-pollution cosmetics. However, it is known that polyphenols in their native form are unstable because they are susceptible to oxidation induced by several environmental agents (metal element traces, light, oxygen) [83].…”

Nutraceuticals: Curative Integrative Cancer Treatment

“…Clinical trial EGCG dosing is based 10 mg/kg body weight, which can be achieved from green tea [18]. Pharmaceuticals may require enormous amounts of the biologic source: 1,520 Taxus chinensis (Chinese yew) trees, an endangered species, are used to produce 1 kg of paclitaxel [19].…”

Morphological alterations in the jejunal mucosa of aged rats and the possible protective role of green tea

“…The role of tea catechins in decreasing risk of many diseases and maintenance of a healthy physiological status have been thoroughly documented throughout different stages of life [14]. GT has well-established hypocholesterolemic, anti-hyperglycemic, hepatoprotective and anticarcinogenic effects [15]. Also, GT stimulates production of endogenous antioxidants during oxidative stress, ischemia and inflammation.…”