Investigation of inhibition kinetics of various plant extracts on polyphenol oxidase enzyme from Paulownia Tomentosa and binding mechanism by molecular docking

Polyphenol oxidase/tyrosinase enzyme, which contains binuclear copper clusters play an important role in melanogenesis and enzymatic browning. Therefore, its inhibitors can be attractive in cosmetics and medicinal industries as depigmentation agents and also in food and agriculture industries as antibrowning compounds. Our aim in this study is to find natural plant extracts that will inhibit the polyphenol oxidase enzyme. The inhibitory effects of Verbascum thapsus, Tanacetum vulgare, Solanum nigrum and Datura stramonium herbal plant extracts obtained from Kosovo on the polyphenol oxidase enzyme activity were investigated. Polyphenol oxidase from the Poulownia tomentosa plant was purified using the three-phase purification method. It is determined that T. vulgare extract showed the most effective inhibitory effect with 0.43 mg/mL IC50 value. In order to explain and support the binding mechanism of the best inhibitor extract, the phenolic content of the T. vulgare extract was determined by LC-MS/MS and the mechanism of the inhibitory effect was explained by performing a molecular docking study for the phenolic compounds it contained at the highest rate.