The invention relates to a flavonoid ester. This flavonoid ester results from the reaction product of at least one flavonoid selected from the group consisting of a flavonoid with a ketone group in the 4-position, a salt, ester or ether of such a flavonoid, and a C-heteroside and/or O-heteroside derivative of such a flavonoid, with the proviso that this flavonoid contains at least one free alcohol group, with an organic monoacid having from 3 to 30 carbon atoms. These flavonoid esters constitute useful active principles for the manufacture of cosmetic, dermopharmaceutical, pharmaceutical, dietetic or agri-foodstuff compositions.