Flavonoids - Bioactive Chemicals Known For Their Antioxidant Activity

Flavonoids belong to the group of polyphenol compounds derived from plant compounds. Flavonoids have been categorized into isoflavonoids (isoflavones) and neoflavonoids. The group includes other bioactive chemicals such as polyphenols and isoflavones, and are mainly known for their antioxidant activity. They have also been known to have many other beneficial effects including the enhancement of immunity, reduction of inflammation, protection of the heart and prevention of various cancers.

Flavonoids exhibit potent antioxidant activity through several mechanisms. They can directly scavenge and neutralize free radicals, which are highly reactive molecules that can damage cells and contribute to oxidative stress. Flavonoids also have the ability to regenerate other antioxidants, such as vitamin C and vitamin E, enhancing the overall antioxidant defense system. Moreover, these compounds can modulate gene expression and enzymatic activity related to antioxidant defense pathways in the body.

Effects on Macrophages

Flavonoids derived from plant products have been noted to stabilize the effects of the immune system. Several autoimmune diseases (wherein the immune system begins destroying healthy cells) are related to an abnormal increase in the function of the immune cells. Numerous studies have reported the benefits of flavonoids in the regulation of the immune system. These studies have reported that, administration of flavonoids decreases the over-expression of macrophages while maintaining their function.

Also, it helps in the regulation of the chemicals being released by the immune cells that results in accumulation of immune cells at a particular location. This regulatory activity of the flavonoids was more pronounced on the macrophages being produced in the bone marrow. Thereby, decrease in the abnormal expression while preserving the function of the immune cells can help in the prevention of autoimmune disorders.

Similar results were published based on a study conducted on cocoa consumption. It was noted that cocoa contained several flavonoids that helped in the stabilization of the immune cells and, controlled the release of chemicals from macrophages and other leucocytes that initiated inflammatory reactions.

Flavonoids have been shown to protect against oxidative stress by reducing the formation of free radicals, preventing oxidative damage to biomolecules such as lipids, proteins, and DNA. Oxidative stress occurs when there is an imbalance between the production of free radicals and the body's ability to neutralize them. Excessive oxidative stress can lead to cellular damage and contribute to the development of chronic diseases, including cardiovascular disease, neurodegenerative disorders, and certain types of cancer.

Polyphenols Enhance Humoral and Cell Mediated Immunity

The immunity in our body has been categorized as humoral and cell mediated immunities. Humoral immunity refers to the immunity carried out by the B-lymphocytes while, cell mediated refers to the immunity by the T-lymphocytes. Humoral immunity is the first line of defense in our body while, the cell mediated immunity is activated if the B-lymphocytes are unable to control an infection. Polyphenols present in green tea have been noted to enhance both these types of immunity with regular consumption.Along with its antioxidant effects the polyphenols also have a role in the repair of DNA and, stimulation of T cells and other immune cells. These effects of polyphenols protect healthy cells and prevent the progression of cancer.

Read More: Top 45 Natural Antioxidant Sources

Administration of flavonoid supplements may therefore have a beneficial effect in the prevention of infectious disorders, autoimmune disorders and also cancers. Further studies are required for determining the safety and efficacy of long term administration of phytonutrients.

Best Food Sources of Flavonoids

a) Citrus Fruits: Oranges, grapefruits, lemons, and limes are excellent sources of flavonoids, particularly hesperidin and naringenin. These flavonoids have been associated with antioxidant, anti-inflammatory, and cardiovascular protective effects.

b) Berries: Blueberries, strawberries, raspberries, and blackberries are rich in anthocyanins, a subgroup of flavonoids known for their potent antioxidant properties. Anthocyanins have been linked to improved cognitive function, cardiovascular health, and anti-cancer effects.

c) Cocoa and Dark Chocolate: Cocoa and dark chocolate contain high levels of flavanols, including catechins and epicatechins. These flavonoids have been shown to have antioxidant and anti-inflammatory effects, as well as potential benefits for cardiovascular health.

d) Green Tea: Green tea is a popular beverage that contains various flavonoids, including epigallocatechin gallate (EGCG). EGCG has been extensively studied for its antioxidant and health-promoting effects, including its potential role in reducing the risk of cardiovascular disease and certain cancers.

e) Soy Products: Soybeans and soy-based products, such as tofu and soy milk, are rich in isoflavones, a type of flavonoid. Isoflavones, such as genistein and daidzein, have been associated with antioxidant, anti-inflammatory, and hormone-regulating properties.

f) Leafy Greens: Vegetables like kale, spinach, and broccoli are good sources of flavonoids, including quercetin and kaempferol. These flavonoids possess antioxidant and anti-inflammatory properties and have been linked to various health benefits.