Flavonoids are a group of natural substances, called phytonutrients, with variable phenolic structures. The molecules that give plants their “colorful hues” are flavonoids, which may be found in a wide variety of plants and are universal pigments of the yellow, red, and purple colors. Flavonoids function also as co-pigments, which allows them to influence color even when they are not directly visible.
They have been ascribed beneficial effects on human and animal health and the current interest is in disease therapy and chemoprevention. These natural products are currently considered an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications.
Several plants produce fruits and vegetables that are high in flavonoids. However, few plants also have them in their leaves and blooms. The most popular sources of flavonoids are apples, grapes, citrus fruits, berries, tea, onions, and extra virgin olive oil.
As reported by epidemiological research, diets high in flavonoids can help prevent cancer and disorders connected to metabolism. Further research demonstrates the wide range of benefits flavonoids possess, including their antioxidant, anti-inflammatory, analgesic, anti-cancer, anti-proliferative, anti-angiogenic, anti-microbial, anti-viral effects, and ability to control vital cellular enzyme functions. As well as anti-malarial and neuroprotective effects.
According to structural differences, flavonoids are categorized as flavanones, flavones, isoflavones, flavonols, and anthocyanins. Flavonols are the most frequently found in food, with quercetin and kaempferol standing as its main representatives. Major dietary sources of flavonols and flavones are onions and tea.