Natural flavonoids for the prevention of colon cancer: A comprehensive review of preclinical and clinical studies

Abstract

Flavonoids comprise a group of natural polyphenols consisting of more than 5,000 subtypes mostly existing in fruits and vegetables. Flavonoids consumption could potentially attenuate the incidence and recurrence risk of colorectal cancers through their antiperoxidative, antioxidant, and anti-inflammatory effects. In addition, these compounds regulate the mitochondrial function, balance the bacterial flora and promote the apoptosis process in cancerous cells. However, some previous data failed to show the effectiveness of flavonoids in reducing the risk of colorectal cancer. In this study, we have reviewed the efficacy of different flavonoids subtypes on the risk of colon cancer and molecular mechanisms involved in this process in both clinical and animal studies. In addition, we tried to elucidate the potential synergy between these compounds and current colorectal cancer treatments. K E Y W O R D Santi-inflammatory, antioxidant, colorectal cancer, flavonoids, supplement

Healthy Effects of Plant Polyphenols: Molecular Mechanisms

“…Some of these studies yielded positive outcomes for what protection against cognitive decline was concerned (reviewed in [84]). The positive effects of plant polyphenols against breast, colon, and colorectal cancer, as emerged from clinical trials, preclinical studies, and primary research, have been recently reviewed critically [85][86][87][88].…”

Polyphenols from Food and Natural Products: Neuroprotection and Safety

“…Those properties attracted the interest of researchers to polyphenols, and many studies highlighted their potential role in the prevention and treatment of various pathological conditions connected to oxidative stress and inflammation, like cancer and cardiovascular and neurodegenerative disorders, and also of pollutant-induced cell damage [8][9][10][11][12]. Moreover, those food products are relatively abundant in the human diet, and several foods and beverages can provide more than 1 mg of polyphenolic content per serving, as shown by the study of Pérez-Jiménez et al (2010) based on data from the Phenol-Explorer database [13].…”

“…In diabetes, tea polyphenols were able to reduce the senescence of glomerular mesangial cells by regulating the activity of miR-126/Akt-p53-p21 pathways [23]. The consumption of flavonoid compounds seemed to also have a beneficial effect on colon-cancer prevention by modulating lysosome enzymes, increasing the expression of apoptotic factors like Bax, Bcl2, and caspase-3 in cancer cells, and regulating cellular respiratory and mitochondrial enzymes [11]. A recent review also pointed out the beneficial role of dietary polyphenols quercetin and epigallocatechin gallate (EGCG) in the prevention and treatment of obesity, with important impact on the prevention of cardiovascular diseases.…”

Do Aspirin and Flavonoids Prevent Cancer through a Common Mechanism Involving Hydroxybenzoic Acids?—The Metabolite Hypothesis

“…Most flavonoids are predicted to prevent the occurrence of cancer through various mechanisms that include their antioxidant properties, enzyme-receptor inhibition, regulation of apoptosis and the modification of signal transduction pathways which are described in several reviews. Interestingly, similar to aspirin, these compounds are also known to downregulate Akt/mTOR pathway, induce mitochondrial mediated apoptosis, inhibit NF-κB pathway, attenuate Wnt signaling, activate AMPK and suppress abnormal epithelial cell proliferation [6,37,38]. Despite these findings, it still remains unclear if the primary mediators of cancer prevention are the parent flavonoids or their degraded products.…”

“…Aspirin and flavonoids affect numerous molecular pathways, some of which overlap. Pathways affected by aspirin alone are indicated in the left, shared pathways are shown in the middle, while pathways affected by flavonoids are shown in the right[6,13,14,[33][34][35][36][37][38][39][40][41][42].…”