The Beneficial Effects of Principal Polyphenols from Green Tea, Coffee, Wine, and Curry on Obesity

Abstract

Several epidemiological studies and clinical trials have reported the beneficial effects of green tea, coffee, wine, and curry on human health, with its anti-obesity, anti-cancer, anti-diabetic, and neuroprotective properties. These effects, which have been supported using cell-based and animal studies, are mainly attributed to epigallocatechin gallate found in green tea, chlorogenic acid in coffee, resveratrol in wine, and curcumin in curry. Polyphenols are proposed to function via various mechanisms, the most important of which is related to reactive oxygen species (ROS). These polyphenols exert conflicting dual actions as anti- and pro-oxidants. Their anti-oxidative actions help scavenge ROS and downregulate nuclear factor-κB to produce favorable anti-inflammatory effects. Meanwhile, pro-oxidant actions appear to promote ROS generation leading to the activation of 5′-AMP-activated protein kinase, which modulates different enzymes and factors with health beneficial roles. Currently, it remains unclear how these polyphenols exert either pro- or anti-oxidant effects. Similarly, several human studies showed no beneficial effects of these foods, and, by extension polyphenols, on obesity. These inconsistencies may be attributed to different confounding study factors. Thus, this review provides a state-of-the-art update on these foods and their principal polyphenol components, with an assumption that it prevents obesity.

Curcumin and Weight Loss: Does It Work?

“…Adapted with permission from ref. [ 125 ]. Copyright 2021 Ohishi, Fukutomi, Shoji, Goto and Lsemura.…”

“…Those upregulated or activated included SIRT1 (sirtuin), Nrf2 (nuclear factor erythroid 2-like 2) and AMPK (Figure 3). [125]. An explanation of the abbreviations can be found at the end of the review.…”

“…Figure 3. Potential anti-obesity mechanisms of curcumin[125]. An explanation of the abbreviations can be found at the end of the review.…”

“…An explanation of the abbreviations can be found at the end of the review. Adapted with permission from ref [125]…”

Targeting Melanoma-Initiating Cells by Caffeine: In Silico and In Vitro Approaches

“…On the other hand, the studies aimed at identifying the role of single bioactive compounds present in coffee are not yet conclusive. In fact, in caffeine-containing beverages, such as coffee, cocoa, and green and black tea, there is a large variety of other bioactive compounds belonging to polyphenols family [31]. It is well-established that in aqueous solution, Caff is able to interact with polyphenols and other aromatic molecules (e.g., theaflavin, quercetin, epicatechin gallate, and gallic acid) forming crystallin complexes [32][33][34].…”