In Silico, In Vitro, and Topical Formulation of Apigenin from Apium graveolens L. as a Natural Anti-Hyperpigmentation Agent

Abstract

Skin hyperpigmentation is associated with excessive melanin synthesis triggered by ultraviolet exposure and catalyzed by melanogenesis enzymes such as tyrosinase, tyrosinase-related protein 1 dan D-Dopachrome tautomerase. Derived from celery (Apium graveolens L.), the flavonoid compound apigenin is explored for its antihyperpigmentation potential through in silico, in vitro, and topical formulation approaches. Molecular docking was performed using BIOVIA Discovery Studio for preparation, PyRx for docking simulations, BIOVIA and PyMOL for visualization. In vitro studies included antioxidant activity evaluation and formulation development using apigenin concentrations ranging from 5 to 200 ppm to determine the optimal concentration. The selected concentration was evaluated with tyrosinase inhibitory assay (TIA). Docking results reveal apigenin’s higher affinity for the target proteins than native ligands, with binding energies of −7.5 kcal/mol (tyrosinase), −7.9 kcal/mol (TYRP1), and −7.2 kcal/mol (DCT). Although apigenin showed slightly higher affinity toward TYRP1, the difference was small and within the deviation range of the docking method. In melanogenesis, tyrosinase functions as the rate-limiting enzyme, whereas TYRP1 acts downstream in melanin intermediate processing. Therefore, in vitro evaluation focused on tyrosinase. Antioxidant and tyrosinase inhibitory activities were evaluated at apigenin concentrations of 5–200 ppm. The optimal activity observed at 25–50 ppm with MDA–TBA inhibition of 65.1% and 61.8%. A Carbopol-based gel formulation exhibited good stability and preserved apigenin’s biological activity. These findings suggest apigenin's potential as an natural antihyperpigmentation agent.