Comparison of the Effect of α-Pinene and Gallic Acid on Tyrosinase Activity

Abstract

Tyrosinase is the key enzyme in melanin synthesis. Therefore, many Tyrosinase inhibitors have been tested in cosmetics and pharmaceuticals. The aim of this study was to compare the anti-Tyrosinase potential of Gallic acid and α-Pinene. The initial analysis was conducted using molecular docking methods. Then, laboratory experiments were performed using mushroom Tyrosinase, with catechol as the substrate and Kojic acid as the standard inhibitor of the enzyme. The antioxidant activity of Gallic acid and α-Pinene was evaluated using DPPH radicals. Docking scores showed that Gallic acid has a strong binding affinity towards Tyrosinase (ΔG = -6.33 Kcal/mol) forming an H-bond with Met 280 and a pi-pi stacking with His 263. α-Pinene could only bind to the active pocket via hydrophobic interactions, resulting in a lower binding affinity (ΔG = ˗3.89 Kcal/mol). Gallic acid showed the highest inhibitory effect (IC50 = 0.130 mg/mL), whereas α-Pinene showed a lower inhibitory capacity (IC50 = 0.392 mg/mL). The types of inhibition were competitive inhibition for Kojic acid and uncompetitive inhibition for Gallic acid. In the DPPH radical scavenging test, EC50 value for Gallic acid and α-Pinene was 0.269 mg/mL and 251.2 mg/mL, respectively. Both in silico and laboratory results were nearly identical. While α- Pinene is not as powerful an inhibitor of Tyrosinase as Gallic acid is, its effect will be increased perhaps by increasing its concentration. The anti-oxidant potential of Gallic acid is significantly higher than that of α-Pinene, so from this point of view also Gallic acid is more harmless and applicable with a higher degree of safeness.