Phytochemicals in Cancer Treatment and Cancer Prevention—Review on Epidemiological Data and Clinical Trials

Abstract

Phytochemicals are a non-nutritive substances that are present in plants and contribute significantly to their flavor and color. These biologically active compounds are classified into five major groups, namely phenolics, carotenoids, organosulfur compounds, nitrogen-containing compounds, and alkaloids, and are known for their potential health benefits in the prevention of various diseases, including cancer. The purpose of this review article is to explore the potential therapeutic benefits of the dietary phytochemicals, such as flavonoids, phenolic acids, phytosterols, carotenoids, and stilbenes, in cancer treatment and prevention based on the epidemiological studies and clinical trials. Although the majority of epidemiological studies report a significant advantage of the heightened phytochemical consumption and increased serum levels of these compounds, linking increased exposure with a lower cancer risk across most cancer types, these effects could not be replicated in the most available clinical trials. In fact, many of these trials were withdrawn early due to a lack of evidence and/or risk of harm. Despite the strong anticancer effect of phytochemicals, as well as their proven efficacy in multiple epidemiological studies, there is still a great need for human studies and clinical trials, with great caution regarding the safety measures. This review article provides an overview of the epidemiological and clinical evidence supporting the potential chemopreventive and anticancer properties of phytochemicals, with a focus on the need for further research in this area.

Hovenia dulcis Suppresses the Growth of Huh7-Derived Liver Cancer Stem Cells by Inducing Necroptosis and Apoptosis and Blocking c-MET Signaling

“…Natural products are a valuable resource for new drug candidates over the past few decades [ 38 ]. Phytochemicals, including flavonoids, stilbenes, terpenoids, and alkaloids, have been widely explored for their potential in cancer prevention and treatment [ 39 ]. More recent studies have revealed the ability of plant extracts or compounds to suppress the stem-like properties of cancer cells [ 40 ].…”

Curcuminoid Nanovesicles as Advanced Therapeutics

“…The sublethal damage caused by the anticancer drug(s) to normal cells leads to rapid cell division as well as frequent toxicity to the organs of patients. Based on epidemiological data, the daily consumption of natural polyphenolic compounds can lower the risk of heart disease as well as the prevalence of various cancer types [24,25].…”

Synergistic Cytotoxicity of Extracts of Chaga Mushroom and Microalgae against Mammalian Cancer Cells In Vitro

“…However, cancer treatments have mostly relied on specific cytotoxic chemotherapy, and their impact on dividing healthy cells results in adverse side effects. There is a renewed interest in natural compounds that can inhibit the growth and metastasis of cancer, and investigations of their adjuvant effects with traditional chemo-drugs are underway [ 6 , 7 ].…”