Abstract
Hyperpigmentation disorders is driven by excess melanin production which pose significant dermatological challenges. Treatments with Kojic acid and hydroquinone pose safety concerns, driving interest in natural alternatives. Calotropis procera (Cp), are plant with rich phytochemical profile, traditionally used for skin ailments and may serve as tyrosinase inhibitors. Tyrosinase is key enzyme in melanogenesis and it is the primary target for inhibition to address hyperpigmentation. This study evaluates the anti-tyrosinase activity of ethyl acetate (EECpL) and butanol (BECpL) extracts from Cp leaf against Kojic acid, a standard tyrosinase inhibitor. Antityrosinase assays revealed a dose-dependent inhibition, with BECpL achieving 88.02% tyrosinase inhibition at 500 μg/mL, closely comparable to Kojic Acid’s 88.45%, and EECpL having 62.25% inhibition. The half-maximal inhibitory concentrations (IC50) shows that BECpL, EECpL, and Kojic Acid have a value of 70.54 μg/mL, 74.05 μg/mL, and 78.40 μg/mL respectively. One-way Anova analysis confirmed BECpL’s is significant potent than Kojic Acid (P = 0.0113), while EECpL showed comparable potency (P = 0.0562). Liquid chromatography-mass spectrometry (LCMS) analysis of BECpL identified 15 phytochemicals out of which molecular docking studies revealed UNPD130317 and Flavonoid-3-O-glycoside as potent tyrosinase inhibitors, exhibiting docking scores of -5.12 and -4.69, respectively compared to kojic acid -5.182. These compounds formed critical hydrogen bonds and Pi-Pi interactions with tyrosinase’s active site residues, such as HIS208, GLY216, GLU158, ASN205 and H2O. These findings suggest that the bioactive phytochemicals of BECpL have significant potential for developing natural tyrosinase inhibitors for cosmetic and pharmaceutical applications targeting hyperpigmentation and related skin disorders. Further studies on the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of these compounds are essential to ensure their safety and efficacy for therapeutic use.

Key words: Hyperpigmentation, Tyrosinase, Calotropis procera, Phytochemicals, Kojic acid