Flavonoids are a class of naturally occurring compounds that are widely distributed in the plant kingdom. They can be found in fruits, vegetables, nuts, seeds, herbs, and spices. Flavonoids have diverse chemical structures and functions. Some flavonoids act as antioxidants, while others have anti-inflammatory or antimicrobial properties.
Flavonoids were first isolated from plants in the 19th century. Since then, hundreds of different flavonoids have been identified. The term “flavonoid” was coined in 1936 by Dr. Walter Norman Haworth, a British chemist and botanist.
Flavonoids are important nutrients for human health. Numerous studies have shown that diets rich in flavonoids are associated with reduced risks of various diseases, including cardiovascular disease and cancer. Flavonoids may also help to improve cognitive function and reduce the risk of age-related neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease.
There are many different types of flavonoids, including anthocyanidins, catechins, chalcones, dihydrochalcones, flavones, flavanones, isoflavones, neoflavones ,and proanthocyanidins . Some common food sources of anthocyanidins include blueberries , cherries , grapes , blackberries , raspberries , strawberries , cranberries , and red wine . Catechins are found in green tea . Chalcones can be found in apples , pears , almonds , and cinnamon . Flavones are present in parsley , thyme , lettuce , cabbage , celery , and endives . Flavanones can be found in oranges and lemons . Isoflavones are abundant in soybeans and tofu . Neoflavones are found in peanuts and pistachios . Proanthocyanidins occur naturally in cocoa beans and dark chocolate .
The health benefits of flavonoids depend on the type of compound consumed as well as the amount consumed daily. For example, intake of high levels of catechins has been linked to improved cardiovascular health; whereas intake of isoflavones has been associated with reduced risks of breast cancer and osteoporosis . It is important to note that most research on the health effects of flavonoids has been conducted on animal models or observational studies in humans; therefore more clinical trials are needed to confirm these potential health benefits