Fisetin is a flavonoid that belongs to the group of secondary plant substances and is found in numerous fruits, vegetables, and other plants. As a chemical substance, it belongs to the group of polyphenols , which are primarily known for their role as natural colorants. Fisetin is found particularly in strawberries, apples, persimmons, and onions , but also in smaller amounts in other fruits and vegetables, as well as in certain herbs and spices. Fisetin not only imparts various color nuances to these plants, but also improves the flavor and increases the antioxidant potential of the foods .