The Administration of 2% Plum (Prunus domestica L.) Extract Cream Inhibited the Increase of Tyrosinase Enzyme Expression and the Amount of Skin Melanin in Male Guinea Pigs (Cavia porcellus) Skin Exposed to UV B Light

Medical science has progressed a lot and Anti Aging Medicine (AAM) is one of the sciences in the medical world that brings a new paradigm. Hyperpigmentation is one of the most common skin problems caused by excessive pigment melanin production. Plums are nutrient-rich and can be eaten raw, dried, or processed. This research aimed to evaluate the administration of 2% plum extract in inhibiting the increase of tyrosinase enzyme expression and the amount of skin melanin in male guinea pigs’ skin exposed to UV B light. This was a randomized post-test-only control group design using 30 male guinea pigs (Cavia porcellus), aged 12-16 weeks, weight 300-350 grams, and divided into three groups, the control group did not get any cream, treatment group 1 received cream base, and treatment group 2 got 2% plum extract cream. Creams were applied daily 0.1 mg/cm2 at 09.40 and 14.00 WITA. All guinea pigs received UV-B irradiation, three times a week with a total dose of 390 mJ/cm2. Tyrosinase enzyme expression was examined by calculating the percentage of cells expressing the enzyme using immunohistochemical methods. On the other hand, the amount of melanin was obtained by calculating the melanin percentage that appeared on histopathological preparations using Masson-Fontana staining. The data obtained were analyzed using the One-way ANOVA test with a significance value of p<0.05. The expression of the tyrosinase enzyme in the control group and group with base cream was not significantly different (22.75 ± 5.50% vs. 21.30 ± 6.50%, p = 0.601). Similarly, the mean amount of melanin (4.42 ± 1.57% vs 4.27 ± 1.63%, p = 0.775). On the other hand, the results of the mean tyrosinase expression and the mean amount of melanin in the group receiving 2% plum extract were significantly lower than the treatment group receiving base cream (7.06 ± 5.18% vs 21.30 ± 6.50% and 0.42 ± 0.19% vs. 4.27 ± 1.63%) with p-value < 0.000. It can be concluded that the administration of 2% plum (Prunus domestica L.) extract cream inhibited the increase in the expression of the tyrosinase enzyme and the amount of melanin in the skin of male guinea pigs (C. porcellus) exposed to UVB light.