– Flavonol (3-Hydroxyflavone) is a member of the class of compounds known as flavonols. 3-hydroxyflavone can be found in a number of food items such as brassicas, pomegranate, red raspberry, and fenugreek. 3-hydroxyflavone is a chemical compound. It is the backbone of all flavonols, a type of flavonoid. It serves as a model molecule as it possesses an excited-state intramolecular proton transfer (ESIPT) effect to serve as a fluorescent probe to study membranes for example or intermembrane proteins.