Yu-Yu Feng

Food therapy is a method that uses the characteristics of food to adjust the functions under the guidance of Chinese medicine theory, so that it can be healthy or cured.It is not only different from drug therapy, but also very different from ordinary diet.Due to the influence of the tumor itself and the side effects of treatment methods, cancer patients often suffer from fatigue and frailty.Nutritionists recommend strengthening nutritional intake.The intake of certain specific foods will not only improve immunity and self-condition, but the substances contained in the food will also change the expression of tumor-related signal pathways and the tumor microenvironment.

Flavonoids are a class of compounds with the structure of 2-phenylchromone (flavone) that exist in nature.It is widely found in many plants, such as a variety of fruits, tea and tomatoes.Flavonoids have many health effects, such as anti-inflammatory, antibacterial, anti-oxidant, lowering blood pressure, lowering blood lipids, anti-aging, and improving immunity.

A study showed that for people who habitually consume moderate or high proportions of flavonoid-rich foods, the risk of death from cancer or heart disease is greatly reduced.A daily intake of approximately 500 mg of total flavonoids minimizes the risk of death from cancer or heart disease.And researchers believe that the intake of different flavonoids from different plants through food and beverages is also very important for health.However, the intake of flavonoids cannot offset all the increased risks caused by smoking or high alcohol intake.

Keap1-Nrf2 is the main regulator of the cytoprotective response to oxidative and electrophilic stress.Keap1 has been shown to interact with Nrf2, which is the main regulator of antioxidant response and is very important for improving oxidative stress.Under normal physiological conditions, Keap1 protein inhibits the activation of Nrf2 protein through interaction with Nrf2 protein and Nrf2 degradation associated with ubiquitination.After oxidative stress caused by ROS, the oxidation of Keap1’s cysteine residues dissociates Nrf2 from Keap1 protein, and then stabilizes Nrf2 through phosphorylation. The phosphorylated Nrf2 translocates into the nucleus and binds to the sMaf transcription factor to the ARE.ARE drives downstream antioxidant defenses to avoid DNA damage and subsequent carcinogenesis to restore normal physiological conditions.

Flavonoids in the diet activate the Nrf2/ARE pathway by affecting the pathway at different stages, and therefore have a potential impact on the chemoprevention of cancer.However, activation of the Nrf2/ARE pathway is not always beneficial, because the same flavonoids may also promote the growth of cancer cells [1].The activation of Nrf2/ARE pathway is mainly carried out by disrupting the interaction between Keap1 and Nrf2, phosphorylation of Nrf2 and preventing Nrf2 ubiquitination [2].In cancer cells, flavonoids can activate the Nrf2/ARE pathway.The expression of several ARE-driven genes enhances the proliferation effect of cancer cells by promoting metabolic responses.For example, glutamine synthesis, glucose metabolism and tricarboxylic acid cycle in NADPH and pentose phosphate pathways [3-6].

In addition to being absorbed in the intestine, the breakdown products of flavonoids can also have biological effects on cancer.But the production of this effect requires a specific environment.Current research shows that flavonoids can be degraded into 4-hydroxybenzoic acid (4-HBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), 2,4,6-trihydroxybenzoic acid (2,4,6-THBA) and 3,4,5-trihydroxybenzoic acid (3,4,5-THBA) [7].Among these major metabolic compounds, 3,4-DHBA and 3,4,5-THBA have the effect of inhibiting the proliferation of cancer cells.In addition, 2,4,6-THBA can exhibit antiproliferative effects by inhibiting the activity of CDK enzyme.However, the production of this effect requires cells to express SLC5A8.2,4,6-THBA can also play an anti-cancer effect from the immune direction: enhance the immune effect of T cells and natural killer cells.

Regarding food therapy, it is increasingly used in the adjuvant treatment and management of various chronic diseases.Multiple scientific research teams have also isolated compounds with great therapeutic potential from food.With the deepening of research, more and more studies have also proved that certain components in these compounds can also promote tumor progression.Fortunately, anti-cancer compounds using flavonoids and other effective compounds as substrates are also being further modified, synthesized and tested.

Competing interests:The authors declare that they have no conflict of interest.

Citation:Feng YY.Flavonoids: Anti-cancer effects of nutritional management.2021;4(4):23.doi: 10.53388/TMRND20211119001.

Executive editor:Jin-Feng Liu.

Submitted:19 November 2021,Accepted:30 November 2021,Online:01 December 2021

? 2021 By Authors.Published by TMR Publishing Group Limited.This is an open access article under the CC-BY license (http://creativecommons.org/licenses/BY/4.0/)