New Insights on the Anticancer Properties of Dietary Polyphenols

Abstract

Cancer, one of the major causes of death across the world, has shown to be a largely preventable disease, highly susceptible to modulation by dietary factors. Phenolic compounds, abundant in vegetables and fruits ubiquitous in diet, were described to play an important role as chemopreventive agents. Since conventional therapeutic and surgical approaches have not been able to control the incidence of most cancer types, the development of chemopreventive strategies is an urgent priority in public health. The current diet phenolic intake is often insufficient to protect from mutagens (either exogenous or endogenous), which leads to the need for dietary supplementation as an alternative approach. Research efforts are placing increasing emphasis on identifying the biological mechanisms and in particular the signal transduction pathways related to the chemopreventive activities of these compounds. These effects are believed to occur by the regulation of signaling pathways such as nuclear factor-kB (NF-kB), activator protein-1 (AP-1) or mitogen-activated protein kinases (MAPK). Dietary polyphenols can exert their effects on these pathways separately or sequentially and in addition the occurrence of crosstalk between these pathways cannot be overlooked. By modulating cell signaling pathways, polyphenols activate cell death signals and induce apoptosis in precancerous or malignant cells resulting in the inhibition of cancer development or progression. However, regulation of cell signaling pathways by dietary polyphenols can also lead to cell proliferation/survival or inflammatory responses due to increased expression of several genes. The present review summarizes the most recent advances providing new insights into the molecular mechanisms underlying the promising anticarcinogenic activity of dietary polyphenols. ß

Antioxidant activities of the extracts from chestnut flower, leaf, skins and fruit

“…In fact, to counteract deleterious action of ROS, phenolic compounds, naturally distributed in plants, are effective (Ferreira, Barros, Soares, Bastos, & Pereira, 2007;Pereira et al, 2006). Polyphenols are bioactive compounds believed to be involved in the defence process against deleterious oxidative damage, at least in part, due to their antioxidant properties (Fresco, Borges, Diniz, & Marques, 2006). Phenolic acids have been widely investigated as potential models for the development of new primary antioxidants, which can prevent or delay in vitro and/or in vivo oxidation processes (Siquet, Paiva Martins, Lima, Reis, & Borges, 2006).…”

“…Phenolic acids have been widely investigated as potential models for the development of new primary antioxidants, which can prevent or delay in vitro and/or in vivo oxidation processes (Siquet, Paiva Martins, Lima, Reis, & Borges, 2006). These phenolic compounds are powerful antioxidants and act in a structure-dependent manner, since they can scavenge reactive oxygen species (ROS), and chelate transition metals which play vital roles in the initiation of deleterious free radical reactions (Fresco et al, 2006).…”

Natural Polyphenols that Display Anticancer Properties through Inhibition of Kinase Activity

“…In this context, polyphenols are investigated as promising medicinal agents for the treatment of bacterial infections, ulcer, hypertension, vascular fragility, allergies, hypercholesterolemia and, most notably, various types of cancer. While a number of literature reviews have addressed the anticancer properties of natural polyphenols (see references [1][2][3][4]), targeting protein kinases with these compounds has not received its due attention in the review literature despite a large amount of original research reports indicating that this strategy holds an immense potential for the development of novel cancer therapies. Therefore, the aim of the present review is to fill this gap in the literature by focusing on polyphenols whose anticancer properties are mediated through specific kinase activity inhibition.…”

Comparative studies on antioxidant activities of extracts and fractions from the leaves and stem of Epimedium koreanum Nakai

“…Fifty one prenyl flavonoid glycosides and eighteen phenolic acids were identified or tentatively identified using the Q-TOF-MS, and an ethylene glycol (Click OEG) column by Wang (2010). Flavonoids was one of the most important contents of Epimedium and it had been shown to display a number of biological activities such as antioxidant (Giovannini et al 2006;Sang et al 2005) antiviral, antifungal (Friedman 2007), anticancerous (Li et al 2007;Fresco et al 2006) antiangiogenic (Oak et al 2005) and anti-inflammatory activities (Dryden et al 2006). Icariin (C 33 H 40 O 15 ; molecular weight: 676.67, ICA) was one of the main flavonoids of Epimedium koreanum Nakai and it was always used as the standard for the quality control of Epimedium related remedies.…”