Ultraviolet B (UVB) irradiation causes skin problems by increasing cellular oxidants, melanogenesis, and morphological changes in melanocytes. Piceatannol (PCT), a phytochemical found in Passiflora edulis fruit seed (PFS), is known for its anti-melanogenesis effects. However, its effect on morphological differentiation related to melanin production had not been studied. This research investigated the impact of PFS extract on inhibiting morphological differentiation, focusing on microphthalmia-associated transcription factor (MITF) mRNA expression and F-actin polymerization in UVB-induced hyperpigmented B16F10 cells.

Three fractions of PFS extract were analyzed for total phenolics, PCT proportion, and antioxidant capacity. The fraction with the highest PCT proportion and antioxidant activity (PFS-F3) was studied for its effects on cellular oxidants, melanin-containing cells, melanin content, MITF mRNA expression, and tyrosinase activity. Additionally, morphological differentiation and F-actin polymerization were analyzed. Results showed that PFS-F3 had the highest antioxidant effect and reduced cellular oxidants, melanin-containing cells, melanin content, MITF mRNA expression, and tyrosinase activity. It also repressed differentiation and F-actin polymerization in UVB-irradiated cells.

In conclusion, PFS extract rich in PCT attenuated morphological differentiation by suppressing MITF mRNA functions and F-actin polymerization, reducing melanin production.