Comparison of the inhibitory effects of vitamin E analogues on melanogenesis in mouse B16 melanoma cells

• Published in: Cytotechnology (Dordrecht) 2009-04, Vol.59 (3), p.183-190
• Main Authors: Kamei, Yuto, Otsuka, Yuri, Abe, Kouichi
• Format: Article
• Language: English
• Subjects: Acetic acid; Biochemistry; Biological and medical sciences; Biomedicine; Biotechnology; Cell culture; Chemistry; Chemistry and Materials Science; Cosmetics; Cytotoxicity; Enzymatic activity; Enzymes; Fundamental and applied biological sciences. Psychology; JAACT Special Issue; Melanin; Melanoma; Pigmentation; Reverse transcription; Skin; Skin pigmentation; Tocopherols; Vitamin E
• ISSN: 0920-9069; 1573-0778
• DOI: 10.1007/s10616-009-9207-y

The effect of eight vitamin E analogues (d-α-, dl-α-, d-β-, d-γ-, and d-δ-tocopherols, d-α- and dl-α-tocopheryl acetates) and 2,2,5,7,8-pentamethyl-6-hydroxychroman (PMC) on melanogenesis were compared in mouse B16 melanoma cells. D-β-tocopherol at 250 μg ml⁻¹ inhibited not only 28% of melanin synthesis in B16 cells, but also 34% of the tyrosinase activity, a very important cascade enzyme involved in the synthesis of melanin in melanoma cells. D-γ-tocopherol also strongly inhibited up to 39% of melanin synthesis and 45% of the tyrosinase enzyme activity at the same concentration. The inhibitory activity of both d-β- and d-γ-tocopherols was observed without cytotoxicity up to a concentration of 250 μg ml⁻¹. Weak activity was also observed with d-δ-tocopherol at 8 μg ml⁻¹ and with PMC at 16 μg ml⁻¹, with 19% and 25% inhibition of melanin synthesis, respectively. However, PMC did not directly inhibit tyrosinase, as was observed with d-β-, d-γ-, and d-δ-tocopherols. Analysis by reverse transcription-polymerase chain reaction showed that the mechanism of melanogenesis inhibition by d-β- and d-γ-tocopherols in cells might be attributed to reduced expression of tyrosinase and tyrosinase related protein-2 mRNA in addition to direct inhibition of the tyrosinase. These findings suggest that both d-β-tocopherol and d-γ-tocopherol might be useful as effective ingredients in whitening cosmetics with lower skin toxicity to prevent or improve skin pigmentation such as skin spots and freckles caused by UV exposure.