In Vitro EVALUATION OF MELANOGENESIS INHIBITION BY TOCOTRIENOL RICH FRACTION

Abstract

Melanogenesis is a process of melanin production, the leading cause of pigmentation in human skin. However, ultraviolet (UV) irradiation can stimulate melanocytes and enhance melanin production. This study aimed to evaluate the effects of tocotrienol-rich fraction, a potent antioxidant, on UVA-induced melanogenesis in melanocytes. Melanocytes were treated with different concentrations of study materials (TRF, alpha-tocopherol (α-TP) and kojic acid (KA)) to determine the cell viability and the effect of TRF on melanin synthesis. Then, the optimum concentration of study materials was used to assess their effect on melanin synthesis in the UVA-irradiated melanocytes. Treatment of melanocytes with different concentrations of TRF and α-TP increased the number of viable cells. The optimum concentration of 62.5 µg mL –1 for study materials was used to determine their effects on melanin synthesis. After seven days, the irradiated and untreated melanocytes showed a significant 10.8% increase in melanin content, indicating that UVA irradiation directly influences melanogenesis. Melanocytes treated with TRF and irradiated with UVA showed a slight decrease in melanin content of about 4% compared to the negative control (irradiated), indicating that TRF may effectively protect cells from UVA irradiation. From findings, TRF could be a useful therapeutic agent for treating skin hyperpigmentation and a practical component to support skin lightening in skincare products.