The present invention features a method of treating at least one sign of aging on the skin selected from the group consisting of enhancing the elasticity of said skin, enhancing the firmness of said skin, and reducing the appearance of wrinkles or cellulite on the skin, by administering to skin in need of such treatment a composition comprising at least one compound of the formula I or formula II: wherein R1, R2, R3, R4, and R5 independently, are selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 hydroxyalkyl, or a cosmetically acceptable salt thereof.