Plain language summary
Novel therapies for cancer treatment using herbs and edible components of plants are continuously being studied as an adjunct to conventional cancer therapies: antitumor drugs and radiation. Resistance to drugs, and tumour recurrence rates suggest that new therapies are needed. This 2019 review discusses the possible strategy of combining flavonoids, nutraceuticals and conventional chemotherapeutic agents to minimise adverse effects, and improve quality of life of patients undergoing traditional treatments. Flavonoids, such as EGCG, Quercetin, Luteolin, Glabridin and Naringin demonstrate several clinically interesting mechanisms: anti-angiogenic and anti-metastatic properties, apoptosis and autophagy promoting activities, and immunomodulatory effects. On the downside there are questions over the low bioavailability of flavonoids from foods. The widely accepted consensus is that combination treatments which embrace novel therapies alongside traditional treatment are clinically safe. The interest in flavonoids is principally for improving chemotherapy sensitivity and minimizing the adverse side effects of these treatments. The molecular mechanisms underlying flavonoids multiple pharmacological effects make them a potential adjunctive agent for cancer chemoprevention although more clinical trials are needed.
Abstract
Cancer is a diverse class of diseases characterized by uncontrolled cell growth with the potential to invade and spread to other parts of the body, and continues to be one of the leading causes of death worldwide. Conventional cancer treatment modalities include antitumor drugs, surgical resection, locally targeted therapies such as radiation therapy. Along with improved understanding of the molecular pathogenesis of various cancers, generation and the use of smart targeted anti-cancer drugs have been challenged. The need for novel therapeutic strategies remains paramount given the sustained development of drug resistance, tumor recurrence, and metastasis. Development of new strategies aimed at improving chemotherapy sensitivity and minimizing the adverse side effects is thus essential for obtaining satisfied therapeutic outcomes for patients and enhancing their quality of life. Emerging evidence has reported that many cancer patients use either herbs employed in complementary therapies or dietary agents that influence cellular signaling worldwide. Numerous components of edible plants, collectively termed phytochemicals that have beneficial effects for health, are being reported increasingly in the scientific literature. Of those, flavonoids have attracted much attention by virtue of its wide variety of biological functions including antioxidant, anti-inflammatory, and anticancer activity. In this review, we highlight the molecular mechanisms underlying its multiple pharmacological effects, especially focusing on cancer chemoprevention. We further discuss possible strategies to develop anticancer therapy by combining flavonoids nutraceuticals and conventional chemotherapeutic agents. We also highlight numerous pharmacokinetic challenges such as bioavailability, drug-drug interactions, which are still fundamental questions concerning its future clinical application.
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