Antimelanogenic Effect of an Oroxylum indicum Seed Extract by Suppression of MITF Expression through Activation of MAPK Signaling Protein.

Peijun Zhao,Chi-Yeol Yoo,Sang-Han Lee,Md Alam,Hee-Jeong Choi,Yeong Cha,Hongyan An,Hyo-Hyun Kim

doi:10.3390/ijms19030760

Abstract

In this study, the antimelanogenic effect of an ethyl acetate fraction of Oroxylum indicum Vent. seeds (OISEA) and its underlying mechanisms in melan-a cells were investigated. Antimelanogenesis activity was confirmed by assessing inhibition of tyrosinase activity and melanin content in the cells. Both transcriptional and translational expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase related protein-1 and 2 (TYRP-1 and TYRP-2), were also examined. The results depicted that pretreatment of OISEA significantly inhibits not only tyrosinase activity, but melanin production and intracellular tyrosinase activity. By repressing the expression of tyrosinase, TYRP-1, TYRP-2, and MITF, OISEA interrupted melanin production. Additionally, OISEA interfered with the phosphorylation of p38, extracellular signal-regulated kinase 1/2 (ERK1/2), and c-Jun N-terminal kinase (JNK), with the reversal of OISEA-induced melanogenesis inhibition after treatment with the specific inhibitors SB239063, U0126, and SP600125. Overall, these results suggest that OISEA can stimulate p38, ERK1/2, JNK phosphorylation, and subsequent suppression of melanin, leading to the inhibition of melanogenic enzymes and melanin production, possibly owing to the presence of polyphenolic compounds.

Highlights

Melanin, a multifunctional biopolymer, is synthesized in melanocytes and transferred to keratinocytes [1]
2.4.2E.4ff.eEcftfsecotfsOofISOEISAEoAnotnhethme RmNRNAAanadndPPrortoetieninEExxpprreessssiioonnooff MMeellaannooggeenneeiiss--RReelalateteddGGeneneses To elucidate the mechanics of OISEA on melanogenesis, we examined the expression of tyTrooseinluacseid, aTtYeRtPh-e1,mTeYcRhPan-2i,csanodf OMIISTEFAinonmemlaenla-anoceglelsneasftiesr, wtreeantmexetnet xwaimthinOeIdSEthAe(e3x, p1r0e, sosrio3n0 of tyroμsgin/masLe), TfoYrR4P-d1a, yTsY
OISEA extended the lag phase by 20 min compared with the control, when its concentration was 100 μg/mL

Summary

Introduction

A multifunctional biopolymer, is synthesized in melanocytes and transferred to keratinocytes [1]. It has many fundamental physiological functions, including contribution to the color of the skin and protection of the skin from ultraviolet radiation (UVR)-induced damage. The inhibitors of melanogenesis have gained substantial attention in clinical and cosmetic research. Several cutaneous depigmentation agents, such as kojic acid, arbutin, and ellagic acid, isolated from natural resources, are used as cosmetic agents [3]. Tyrosinase (copper-containing enzyme) plays a pivotal role in melanogenesis. It catalyzes the two rate-limiting steps of melanin biosynthesis: first, production of 3,4-dihydroxyphenylalanine (DOPA) by hydroxylation of tyrosine, referred to as monophenolase activity, and second, formation

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Discussion

Conclusion