Anti-Cancer Effects of Green Tea Epigallocatchin-3-Gallate and Coffee Chlorogenic Acid

Abstract

Tea and coffee are consumed worldwide and epidemiological and clinical studies have shown their health beneficial effects, including anti-cancer effects. Epigallocatechin gallate (EGCG) and chlorogenic acid (CGA) are the major components of green tea polyphenols and coffee polyphenols, respectively, and believed to be responsible for most of these effects. Although a large number of cell-based and animal experiments have provided convincing evidence to support the anti-cancer effects of green tea, coffee, EGCG, and CGA, human studies are still controversial and some studies have suggested even an increased risk for certain types of cancers such as esophageal and gynecological cancers with green tea consumption and bladder and lung cancers with coffee consumption. The reason for these inconsistent results may have been arisen from various confounding factors. Cell-based and animal studies have proposed several mechanisms whereby EGCG and CGA exert their anti-cancer effects. These components appear to share the common mechanisms, among which one related to reactive oxygen species is perhaps the most attractive. Meanwhile, EGCG and CGA have also different target molecules which might explain the site-specific differences of anti-cancer effects found in human studies. Further studies will be necessary to clarify what is the mechanism to cause such differences between green tea and coffee.

Phenolic Content and Antimicrobial and Anti-Inflammatory Effects of Solidago virga-aurea, Phyllanthus niruri, Epilobium angustifolium, Peumus boldus, and Ononis spinosa Extracts

“…Finally, prostate cancer PC3 cells were treated with single extracts and Fluxonorm ® . Specifically, E. angustifolium, P. niruri, P. boldus, and Fluxonorm ® showed similar antiproliferative effects ( Figure 13) that could be related, at least partially, to multiple anti-inflammatory and antioxidant mechanisms [57][58][59]. In this context, it is sensitive to hypothesize that phenolic compounds present in the tested extracts could be responsible for the observed antiproliferative effects.…”

Beneficial Effects of Epigallocatechin-3-O-Gallate, Chlorogenic Acid, Resveratrol, and Curcumin on Neurodegenerative Diseases

“…Therefore, one can assume that 4 polyphenols described here exhibit very similar biological activities on NDDs. Many of these effects on NDDs can be explained by molecular events illustrated in Figure 2 which is depicted based on previous data [ 1 , 3 , 5 , 6 , 8 , 23 , 24 , 53 , 198 , 201 , 202 , 203 , 204 ]. These polyphenols in common can upregulate or activate AMPK [ 1 , 114 , 129 , 187 , 198 ], SIRT1 [ 25 , 129 , 130 , 187 , 198 , 205 ], and PGC-1α [ 23 , 189 , 205 , 206 ] and downregulate ROS and NF-κB [ 1 , 3 ].…”

“…Dual property of these polyphenols acting as an anti-oxidant and a pro-oxidant has been well documented [ 1 , 3 , 5 ]. However, it remains unknown how these polyphenols can activate AMPK, although involvement of ROS, protein kinase A (PKA), CaMKK-β, and LKB1 has been postulated [ 1 , 3 , 207 ].…”

“…Black tea and oolong tea are made from the leaves of same tea plant Camellia sinensis as a source of green tea, but have much lower contents of EGCG due to loss occurring in production processes. There has been some confusion in the nomenclature of chlorogenic acids [ 3 ], but chlorogenic acid (CGA) in this review represents 5-caffeoylquinic acid. Wines contain trans- and cis -forms of resveratrol [ 4 ].…”

“…We have presented several review articles related to the effects of EGCG and other polyphenols on cancer, obesity, and NDDs [ 1 , 3 , 5 , 6 , 7 ]. In this article, we provide updated information on the effects of these foods and their representative polyphenols on NDDs with discussions on mechanistic aspects of their actions mainly based on laboratory findings from cellular and animal experiments.…”