Black Soybean (Glycine max (L.) Merr.) 30% Ethanol Extract Cream Inhibited The Increase of Tyrosinase Enzyme Expression and The Amount of Melanin Same Effective as 4% Hydroquinone Cream on Guinea Pig (Cavia porcellus) Skin

Background: Hyperpigmentation is one of the signs of skin aging which is mostly caused by Ultraviolet B (UVB) rays exposure. The gold standard for hyperpigmentation therapy is hydroquinone (HQ) but its long-term use can cause side effects such as irritation, rebound phenomenon, and even ochronosis. Black soybeans contain active ingredients that can prevent the increase of tyrosinase enzyme and the amount of melanin so that it can be used as an alternative therapy for hyperpigmentation. This study aims to prove that the administration of 30% black soybean extract cream was as effective as 4% HQ cream in inhibiting the increase of tyrosinase enzyme expression and the amount of melanin in guinea pig skin exposed to UVB rays. Methods: This study used a post-test only control group design method with 30 guinea pigs as samples. The sample was divided into three groups of 10 each. The P1 group was given the base cream, the P2 group was given the 4% HQ cream, while the P3 group was given the 30% black soybean extract cream. Each group was exposed to UVB rays with a total dose of 390mJ/cm2 for 2 weeks, after that the guinea pig skin tissue was taken and histopathological preparations were made for examination of tyrosinase enzyme expression and the amount of melanin. The data obtained were analyzed using one way ANOVA, then the differences between groups were analyzed using the Least Significant Difference (LSD) test. Results: The results showed that the mean of the tyrosinase enzyme expression and the amount of melanin in the black soybean extract group P3 (12.880±3.327% and 3.16±1.486) were not significantly different from the HQ4% group P2 (9.690±2.176% and 2.18±1.117), while the mean of the base cream group P1 (25.78±5.392% and 12.080±3.150) was the highest among the three groups. The LSD test showed a significant difference between the base cream group (P1) and the other groups (p<0.01), but there was no significant difference between the 4% hydroquinone group (P2) and the 30% black soybean extract treatment group (P3) (p >0.05). Conclusion: The conclusion of this study was that 30% black soybean ethanol extract cream inhibited the increase of tyrosinase enzyme expression and the amount of melanin as effective as 4% HQ cream on guinea pig skin exposed to UVB light.