Fermented rice bran downregulates MITF expression and leads to inhibition of alpha-MSH-induced melanogenesis in B16F1 melanoma

• Published in: Bioscience, biotechnology, and biochemistry Vol. 73; no. 8; pp. 1704 - 1710
• Main Authors: Chung, S.Y.(Doosan R and D Center, Youngin (Korea R.)), Seo, Y.K, Park, J.M, Seo, M.J, Park, J.K, Kim, J.W, Park, C.S
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 01.08.2009; Japan Society for Bioscience Biotechnology and Agrochemistry
• Subjects: alpha-MSH - antagonists & inhibitors; alpha-MSH - metabolism; Animals; Biological and medical sciences; BRAN; Cell Line, Tumor; Down-Regulation - drug effects; Enzyme Activation - drug effects; EXPRESION GENICA; EXPRESSION DES GENES; Extracellular Signal-Regulated MAP Kinases - metabolism; FACTEUR DE TRANSCRIPTION; FACTORES DE TRANSCRIPCION; FERMENTACION; FERMENTATION; fermented rice bran; Fundamental and applied biological sciences. Psychology; GENE EXPRESSION; HARINAZA DE ARROZ; Humans; Intracellular Space - drug effects; Intracellular Space - metabolism; LACTOBACILLUS; Lactobacillus rhamnosus; Melanins - biosynthesis; melanogenesis; MELANOMA; Melanoma - metabolism; Melanoma - pathology; MELANOME; Melanosomes - drug effects; Melanosomes - metabolism; Mice; microphthalmia-associated transcription factor (MITF); Microphthalmia-Associated Transcription Factor - metabolism; Monophenol Monooxygenase - antagonists & inhibitors; Oryza - chemistry; Oryza - metabolism; Oryza sativa; Plant Extracts - pharmacology; Plant Extracts - toxicity; POLIFENOLES; POLISSURE DE RIZ; POLYPHENOL; POLYPHENOLS; RICE POLISHINGS; Saccharomyces cerevisiae; SALVADO; SON; TOXICIDAD; TOXICITE; TOXICITY; TRANSCRIPTION FACTORS; Cereal bran; fermented rice bran; Malignant melanoma; melanogenesis; micro-phthalmia-associated transcription factor (MITF); Melanocyte stimulating hormone; Inhibition; Transcription factor; Fermented product
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.80766

Rice bran contains various polyphenolic compounds with anti-oxidative activities, and it has long been known to inhibit melanogenesis, but the inhibition mechanism has not been fully elucidated. Cofermentation of rice bran with Lactobacillus rhamnosus and Saccharomyces cerevisiae significantly reduced the cytotoxicity of the resulting extract to B16F1 melanoma cells. Marked reduction of α-melanocyte stimulating hormone (MSH) induced melanin synthesis was also observed upon treatment with fermented rice bran extract but it had no direct inhibitory effect on tyrosinase activity, while the intracellular tyrosinase activity was reduced by the extract. This result was further confirmed by an immunoblot assay measuring the level of tyrosinase protein. In addition, the expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis, was significantly decreased by the extract. All together, the fermented rice bran extracts showed an inhibitory effect on melanogenesis through downregulation of MITF, along with reduced cytotoxicity.