In plants, flavonoids have long been known to be synthesized in particular sites and are responsible for the color and aroma of flowers, and in fruits to attract pollinators and consequently fruit dispersion to help in seed and spore germination, and the growth and development of seedlings.
They have several important functions in plants, such as providing protection against harmful UV radiation or plant pigmentation. In addition, they have antioxidant, antiviral and antibacterial properties. They also regulate gene expression and modulate enzymatic action.
Flavonoids also have roles against frost hardiness, drought resistance and may play a functional role in plant heat acclimatisation and freezing tolerance.
Flavonols are flavonoids with a ketone group. They are building blocks of proanthocyanins. Flavonols occur abundantly in a variety of fruits and vegetables. The most studied flavonols are kaempferol, quercetin, myricetin and fisetin. These compounds are found in olive oil, berries, onions, kale, grapes, tomatoes, red wine, and teas.
Epidemiological studies suggest that high intakes of dietary flavonoids are associated with decreased cardiovascular disease mortality and risk factors. Several antioxidant flavonoids are found in bananas, most notably catechins. They have been linked to various health benefits, including a reduced risk of heart disease.
They reduce oxidative stress by upregulating antioxidant enzymes to prevent cholesterol ester accumulation within macrophages anti-inflammatory actions by inhibiting platelet adhesion, secretion, and aggregation.
Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications.
Flavonoid compounds in food and vegetables
