Novel and Potential Photoprotective and Tyrosinase Inhibitory Effects of Tetrastigma erubescens Extracts: Evidence from In Vitro Assays and Computational Approach.

Tetrastigma erubescens, a native medicinal plant of Vietnam, has long been used in folk medicine to manage various diseases, including skin-related issues. However, limited research has been conducted on this herb's bioactivities and chemical composition. This study aims to investigate the chemical constituents and evaluate the anti-tyrosinase activity and UV-A/UV-B absorption capacity of T. erubescens extracts, highlighting their potential as natural sources for skin-whitening and sun protection agents. In vitro assays demonstrated that the ethyl acetate (EA) extract of T. erubescens exhibited a significant UV-A and UV-B absorption capacity. Notably, this extract showed a strong anti-tyrosinase activity for the first time, with a maximum inhibition rate of 99.2% and an IC(50) value of 70.3 µg/mL. Based on the UHPLC and GCMS analysis, phenolic compounds (1-9) and ten volatile constituents (10-19) were identified in the EA extract of T. erubescens. Of these, almost all volatiles and some phenolics were reported for the first time in this genus. The molecular docking analysis revealed that all identified phytochemicals showed a comparable or greater binding affinity to both mushroom tyrosinase (docking scores: from -7.5 to -14.1 kcal/mol) and human tyrosinase (from -6.7 to -14.8 kcal/mol) than kojic acid (-8.7 and -8.6 kcal/mol, respectively). In addition, these identified compounds showed favorable drug-like properties and low toxicity risks via ADMET prediction and Lipinski's Rule of Five analyses. The results obtained in this work suggest that the EA extract of T. erubescens is a promising natural source of bioactive compounds for cosmetic applications, particularly in whitening and sun protection formulations.