Diosmetin is a natural flavonoid that inhibits the activity of human CYP1A enzyme. Specifically, it can inhibit cytochrome P450 (CYP) subtypes CYP1A1 and CYP1B1. with inhibition constants (Kis) of 89 nM and 16 nM, respectively. This inhibitory activity makes dioscorea potentially useful in drug metabolism and biotransformation.
Diosmetin also exhibits inhibitory activity against polyphenol oxidase (PPO). Studies using spectroscopy and computer simulation methods have shown that Diosmetin inhibits PPO activity in a reversible mixing manner, with an IC50 value of (302.9±1.82) μmol·L^-1. Fluorescence results show that Diosmetin quenches the intrinsic fluorescence of PPO in a static manner, and the formation of a complex between the two is mainly driven by hydrophobic interactions. In addition, it can also induce an increase in the α-helix content of PPO, a decrease in the β-fold and random coil content, and a tightening of the enzyme structure, thereby further inhibiting the catalytic activity of PPO.
As a c-Kit inhibitor, Diosmetin can block information transmission, thereby achieving a certain whitening effect. c-Kit is a typical type III receptor tyrosine kinase. In addition to being closely related to tumors, it also affects the proliferation and differentiation of melanocytes. When the skin is exposed to ultraviolet rays, melanin increases, and c-Kit plays a role in information transmission in this process. Therefore, it can indirectly affect the production and distribution of melanin by inhibiting the activity of c-Kit. Diosmetin also inhibits the activation of carcinogens by inhibiting the CYP1A1 enzyme, thus having a potential anti-cancer effect. This discovery provides a theoretical basis for the application of Diosmetin in cancer prevention and treatment.