Fermented rice bran downregulates MITF expression and leads to inhibition of alpha-MSH-induced melanogenesis in B16F1 melanoma.
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 alpha-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.
Chung
So-Young
SY
Doosan R&D Center, Gyeonggi-do, Korea.
Seo
Young-Kwon
YK
Park
Jung-Min
JM
Seo
Min-Jae
MJ
Park
Jung-Keug
JK
Kim
Jin-Wook
JW
Park
Chang-Seo
CS
D000818:Animals; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005285:Fermentation; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008543:Melanins / Q000096:biosynthesis*; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D020460:Melanosomes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors; D012275:Oryza / Q000737:chemistry / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology / Q000633:toxicity; D000521:alpha-MSH / Q000037:antagonists & inhibitors / Q000378:metabolism*
D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor; D010936:Plant Extracts; D000521:alpha-MSH; D014442:Monophenol Monooxygenase; D048049:Extracellular Signal-Regulated MAP Kinases