After studying recent research, our scientists have come to see that onion extract is an excellent source of polyphenol and flavonoid. It has been showed that the total polyphenol content of onions is much higher than many people expect. (Polyphenols are one of the largest categories of phytonutrients in food. This category includes all flavonoids as well as tannins). The total polyphenol content of onion is higher than tomatoes, carrots and red bell pepper. Besides, onion is one of the richest sources of flavonoids.