Dr. Louay Labban
• Polyphenolic compounds that are ubiquitous in nature and are categorized, according to chemical structure, into flavonols, flavones, flavanones, isoflavones, catechins, anthocyanidins and chalcones
What are flavonols?
• Flavonols are phytochemical compounds found in high concentrations in a variety of plant-based foods and beverages. Based on their structure, flavonols are classified as flavonoids and include the following compounds: quercitin, kaempferol, and myricetin.
• Over 4,000 flavonoids have been identified, many of which occur in fruits, vegetables and beverages (tea, coffee, beer, wine and fruit drinks).
• The flavonoids have aroused considerable interest recently because of their potential beneficial effects on human health they have been reported to have antiviral, antiallergic, antiplatelet, antiinflammatory, antitumor and antioxidant activities.
• Antioxidants are compounds that protect cells against the damaging effects of reactive oxygen species, such as singlet oxygen, superoxide, peroxyl radicals, hydroxyl radicals and peroxynitrite.
An imbalance between antioxidants and reactive oxygen species results in oxidative stress, leading to cellular damage. Oxidative stress has been linked to cancer, aging, atherosclerosis, ischemic injury, inflammation and neurodegenerative diseases (Parkinson’s and Alzheimer’s).
• Flavonoids may help provide protection against these diseases by contributing, along with antioxidant vitamins and enzymes, to the total antioxidant defense system of the human body.
• Epidemiological studies have shown that flavonoid intake is inversely related to mortality from coronary heart disease and to the incidence of heart attacks.
• The recognized dietary antioxidants are vitamin C, vitamin E, selenium, and carotenoids. However, recent studies have demonstrated that flavonoids found in fruits and vegetables may also act as antioxidants.