Background: Melanin is produced through melanogenesis which involves several molecular processes with microphthalmia-associated transcription factor (MITF) as the main regulator of melanin synthesis. Hyperpigmentation is one of aging sign that happens due to melanin buildup in the skin. Hyperpigmentation can be caused by many factors, and one of the most frequent cause is ultraviolet (UV) ray exposure. Robusta coffee silverskin is a thin layer on a green coffee bean that is detached from the bean through roasting process, and is a waste product of coffee production. However, coffee silverskin contains high amount of phenolic and flavonoid compounds, and is categorized as strong antioxidant. The purpose of this study was to prove that administration of 30% Robusta coffee silverskin ethyl acetate fraction cream inhibited the increase of MITF expression and melanin amount in the skin of male adult guinea pig exposed to UVB ray. Methods: This study used randomized post-test only control group design. Subjects used in this study were healthy male guinea pigs with age ranging from 3-4 months and average weight 300-350g. Total samples used in this study were 36 guinea pigs divided evenly into two groups, Group K that were only exposed to UVB ray, and Group P that were exposed to UVB ray and 30% Robusta coffee silverskin ethyl acetate fraction cream. Total UV ray used during two weeks were 390mJ/cm2. 30% Robusta coffee silverskin ethyl acetate fraction cream was applied twice a day on guinea pigs at the days they were not exposed to UVB ray, and at the days they were exposed to UVB ray, the cream was applied 20 minutes before and 4 hours after the exposure. MITF expression was examined under the microscope with MITF antibody kit, and melanin amount was examined with Masson-Fontana staining. Results: Result of the experiment showed higher MITF expression and melanin amount in the Group K. Comparison analysis with 2 independent samples t-test shows average MITF expression in the Group K and Group P 27.833 vs 15.422 % MITF, and 16.828 vs 7.822 % pixel melanin for the melanin amount. The differences between two variables were meaningful as the p value <0.001. Conclusions: Conclusion for this experiment is that 30% Robusta coffee silverskin ethyl acetate fraction cream inhibited the increase of MITF expression and melanin amount in adult male guinea pigs exposed to UVB.

MITF

Melanin

Ultraviolet B Ray

Robusta coffee silverskin ethyl acetate fraction