Identifikasi Aktivitas Inhibitor Enzim Tirosinase Senyawa Turunan Flavonoid pada Kulit Buah Cokelat (Theobroma cacao L) secara In Silico

Abstract

Limbah kulit buah cokelat diketahui mengandung berbagai senyawa aktif, termasuk di antaranya adalah golongan flavonoid. Senyawa flavonoid diketahui berpotensi memiliki aktivitas inhibitor enzim tirosinase, suatu enzim yang menstimulasi proses pembentukan melanin. Penelitian ini bertujuan untuk mengevaluasi interaksi antara senyawa flavonoid dari kulit buah cokelat dengan enzim tirosinase menggunakan metode penambatan molekuler secara in silico. Pengujian dilakukan dengan beberapa tahapan yakni preparasi makromolekul enzim, pemodelan molekul senyawa uji, identifikasi sisi aktif molekul enzim, identifikasi dan evaluasi penambatan molekuler, serta simulasi dinamika molekuler senyawa uji dengan molekul enzim. Hasil simulasi penambatan molekuler antara molekul enzim dengan ligan alaminya yakni tirosin memberikan energi ikatan sebesar -4,91 kkal/mol. Senyawa flavonoid dari kulit buah cokelat yakni apigenin, epikatekin, katekin, kaemferol, kuersetin, dan kuersitrin  diketahui memiliki afinitas pada sisi aktif enzim tirosinase dengan energi ikatan berturut turut -6,14; -6,17; -6,01; -5,89; -6,13; -6,81 kkal/mol. Hasil simulasi dinamika molekuler menunjukkan kuersitrin memiliki stabilitas yang baik dengan nilai RMSD rata-rata dan nilai energi bebas ikatan MM/PBSA masing-masing sebesar ±1,73 Å dan -80,12 kJ/mol. Hasil penelitian menunjukkan bahwa senyawa turunan flavonoid tersebut mampu berikatan dengan sisi aktif enzim tirosinase dengan afinitas yang lebih baik dibandingkan dengan ligan alaminya diamati dari nilai energi ikatannya. Senyawa turunan flavonoid yang terkandung dalam kulit buah cokelat berpotensi menjadi inhibitor kompetitif dari enzim tirosinase.

Identification of In Silico Tyrosinase Inhibitory Activity of Flavonoid Derivative Compounds in Cocoa Pod Husk (Theobroma cacao L.). Cocoa pod husk was known to contain several active compounds, such as flavonoids. Flavonoid compounds are known to potentially have inhibitory activity of the tyrosinase, the enzyme which stimulates melanin synthesis.This study was conducted to evaluate the molecular interaction between flavonoids from cocoa pod husk with tyrosinase enzyme using in silico molecular docking method. The study was carried out through several stages, including preparation of enzyme macromolecules, modeling the molecule of the test compound, identifying the active site of the enzyme molecule, identifying and evaluating molecular docking, and molecular dynamics simulations of the test compound with the enzyme molecule. Molecular docking simulation between the enzyme and its natural ligand (tyrosine) produces binding energy of -4.91 kcal/mol. Flavonoid compounds from cocoa pod husk, including apigenin, epicatechin, catechin, kaempferol, quercetin, dan quercitrin, have an affinity on the active site of the enzyme with binding energy were -6.14; -6.17; -6.01; -5.89; -6.13; -6.81 kcal/mol, respectively. Then the molecular dynamics simulation shows quercitrin has good stability interaction with the average RMSD value and the MM/PBSA binding-free energy values of ±1.73 Å and -80.12 kJ/mol, respectively. The results showed that flavonoids of cocoa pod husc extract have an affinity to the active site of the enzyme, with a stronger binding energy than the original ligand. The flavonoid compounds of cocoa pod husk potential as a competitive inhibitor of the tyrosinase enzyme.