Chemoprotective Mechanism of the Natural Compounds, Epigallocatechin- 3-O-Gallate, Quercetin and Curcumin Against Cancer and Cardiovascular Diseases

Abstract

Cancer and cardiovascular disease (CVD) chemoprevention can be achieved by the use of natural, synthetic, or biologic compounds to reverse, suppress, or prevent the development of diseases. Chemoprevention is a potential anti-cancer approach, which has reduced secondary effects in comparison to classical prophylaxis. Natural compounds such as flavonoids reduce oxidative stress, which is the most likely mechanism in the protective effects of these compounds. Even though the exact mechanisms of action are not well understood another central action mechanism of polyphenolic flavonoids seems to be an induction of apoptosis as demonstrated in numerous cellular systems. Moreover, flavonoids may modulate protein and lipid kinase signaling pathways. Understanding the mechanism of these natural products will contribute to the development of more specific preventive strategies against cancer and CVD. Much of the research in the field is focused on epigallocatechin-3-O-gallate (EGCG), quercetin and curcumin, which were found to have beneficial effects against cancer and CVD. We review the chemoprotective mechanisms through which these natural compounds exert their beneficial effects against cancer and CVDs.

Influence of the flavonoids apigenin, kaempferol, and quercetin on the function of organic anion transporting polypeptides 1A2 and 2B1

“…Ginkgo biloba formulations). In vitro and in vivo studies indicate pharmacological effects of flavonoids on prevention of cardiovascular diseases as well as anticancerogenic and antioxidative effects [1][2][3][4].…”

Modulation of PI3K-LXRα-dependent lipogenesis mediated by oxidative/nitrosative stress contributes to inhibition of HCV replication by quercetin

“…Much attention has been given to the potential health-promoting properties of flavonoids due to their reported wide range of activities in the prevention of common diseases, including coronary heart disease, cancer, neurodegenerative disease, gastrointestinal disorders and others. [16][17][18] Information on the potential benefits of flavonoids in the treatment of hepatitis C is relatively limited and sometimes contradictory, 19,20 although some flavonoids, including quercetin, one of the most abundant flavonol-type flavonoids present in the human diet, seem to inhibit the replication of HCV. [21][22][23] On the basis of these data, in the current research we explored the effects of different natural antioxidant flavonoids on HCV replication in an in vitro model.…”

Quercetin inhibits a large panel of kinases implicated in cancer cell biology

“…The anticancer activity of the flavonols was first attributed to their ability to donate electrons from their phenolic hydroxyl groups (2,6). However, although there has been a major focus on the antioxidant properties of flavonoids (7), there is an emerging view that the flavonoids, including quercetin, do not act only as conventional hydrogendonating antioxidants but may also exert modulatory actions on cells through both protein kinase and lipid kinase signalling pathways (8,9). In addition, flavonoids have been reported to act on phosphoinositide (PI) -3-kinase, Akt/protein kinase B (PKB), tyrosine kinases, protein kinase C (PKC) and mitogenactivated protein (MAP) kinase signalling cascades (8,9).…”

“…Flavonoids, including quercetin, may also influence the activity of epigenetic-modifying enzymes in cancer cells (10) and/or induce apoptosis via the mitochondrial pathway (7). Quercetin aglycone has been shown to modulate several signal transduction cascades involving the MEK/ERK and NRF2/KEAP1 pathways, which are associated with the processes of inflammation and carcinogenesis (6).…”

“…Quercetin also induces ubiquitination and down-regulation of HER-2/ NEU, a transmembrane tyrosine kinase that acts as a coreceptor together with other EGFR (epithelial growth factor receptor) family members (11). Jagtap et al (7) provided a list of about 20 molecular targets of quercetin.…”