New Record of Potential Tyrosinase Inhibitory, Antioxidant, and Photoprotective Effects of Vietnamese <i>Castanea mollissima</i> Extracts

In this study, the potential anti-tyrosinase, antioxidant, and ultraviolet (UV) absorption efficiency of the extracts of different parts of Castanea mollissima were evaluated. The leaf extract exhibited the most potential antioxidant effect with 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging abilities of >90%. C. mollissima extracts showed high UV-A and UV-B absorption efficiency. In addition, screening of the leaf extract demonstrated C. mollissima leaves as a rich source of tyrosinase inhibitors with maximum inhibitory activity and half-maximal inhibitory concentration values of 96% and 336.43 µg/mL, respectively. This is the first-ever report of screening of leaf extract for its potential activities. Eighteen phyto-compounds were identified from the C. mollissima leaf extract using gas chromatography-mass spectrometry and high-performance liquid chromatography techniques. Of these, the content of compounds 10, 11, 12, 13, 14, and 16 in the C. mollissima leaf extract was significantly high (14.35-88.42 µg/g). The molecular docking, absorption, distribution, metabolism, excretion, and toxicity, and Lipinski's rule of five analyses indicated high interaction efficacy of all the major compounds (docking score values of -6.75 to -8.89 kcal/mol) with the target enzyme tyrosinase, had drug properties, and were non-toxic for human use.