Depigmentation Activity of Secang (Caesalpinia Sappan L.) Extract Through Tyrosinase, Tyrosinase Related Protein-1 and Dopachrome Tautomerase Inhibition

Abstract

Excessive exposure of UV light increase melanin synthesis and cause hyperpigmentation of the skin. The pharmacological activity of secang (Caesalpinia sappan L.) with the main compound, brazilien and brazilin as antioxidants that have potency as free radicals scavenger and directly inhibit tyrosinase activity in the process of melanogenesis. This study aims to determine the inhibitory ability of secang ethanolic extract on tyrosinase enzymes in vitro and evaluate the affinity of brazilein and brazilin as skin depigmentation agents against melanogenesis target protein in silico using molecular docking. In vitro testing using tyrosinase inhibitor assay with L-DOPA as its substrate and calculated the percentage inhibition value and IC50. The IC50 of the extract than compared with the positive control, namely kojic acid and ascorbic acid. Insilico research was carried out using autodock 4.2 program by evaluating the binding energy between the active compound of brazilein and brazilin with melanogenesis protein. Inhibition of the tyrosinase enzyme is showed through the IC50 value from ethanolic extract, kojic acid and ascorbic acid respectively 104 μg/ mL, 44 μg/mL and 37 μg/mL. Binding energy of the molecular docking process between brazilein, brazilin, kojic acid and ascorbic acid with the target protein of melanogenesis enzymes (tyrosinase, tyrosinase related protein 1, and D-Dopachrome tauomerase) are -8.37; -6.56; -5.03; -5.35 kcal/mol in tyrosinase, -7.75; -6.40; -5.32; -5.8 kcal/mol in tyrosinase related proteins 1 and -9.93; -8.26; -5.8; -6.52 kcal/mol in D-Dopachrome tautomerase. Secang ethanolic extract could be developed into a skin lightening agent or depigmentation agent through inhibition of 3 target proteins that induce melanogenesis. Although invitro results show the inhibitory ability of the tyrosinase enzyme is lower than kojic acid and ascorbic acid but in silico, it is seen that brazilein and brazilin in secang ethanolic extract have a stronger affinity compared to kojic acid and ascorbic acid. For this reason, it is necessary to purify the extract into a fraction so that it can get more active ingredients of brazilein and brazilin, and in vitro testing for inhibition of the tyrosinase related protein 1 enzyme, and D-Dopachrome tautomerase.