title: Mechanistic studies of anti-hyperpigmentary compounds: elucidating their inhibitory and regulatory actions.
abstract: Searching for depigmenting agents from natural sources has become a new direction in the cosmetic industry as natural products are generally perceived as relatively safer. In our previous study, selected Chinese medicines traditionally used to treat hyperpigmentation were tested for anti-hyperpigmentary effects using a melan-a cell culture model. Among the tested chemical compounds, 4-ethylresorcinol, 4-ethylphenol and 1-tetradecanol were found to possess hypopigmentary effects. Western blot analysis, reverse transcriptase polymerase chain reaction (RT-PCR), cyclic adenosine monophosphate (cAMP) assay, protein kinase A (PKA) activity assay, tyrosinase inhibition assay and lipid peroxidation inhibition assay were performed to reveal the underlying cellular and molecular mechanisms of the hypopigmentary effects. 4-Ethylresorcinol and 4-ethylphenol attenuated mRNA and protein expression of tyrosinase-related protein (TRP)-2, and possessed antioxidative effect by inhibiting lipid peroxidation. 1-Tetradecanol was able to attenuate protein expression of tyrosinase. The hypopigmentary actions of 4-ethylresorcinol, 4-ethylphenol and 1-tetradecanol were associated with regulating downstream proteins along the PKA pathway. 4-Ethylresorcinol was more effective in inhibiting melanin synthesis when compared to 4-ethylphenol and 1-tetradecanol.
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. rorolam@hotmail.com.
authors.forename: Rosanna Y Y
authors.initials: RY
authors.lastname: Lam
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. linzx@cuhk.edu.hk.
authors.forename: Zhi-Xiu
authors.initials: ZX
authors.lastname: Lin
authors.affiliation: Faculty of Medicine and Biomedical Sciences, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK. esviders@sgul.ac.uk.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Sviderskaya
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. chkcheng@cuhk.edu.hk.
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017495:Hyperpigmentation / Q000235:genetics / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism; D010636:Phenols / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D010636:Phenols; C042291:4-ethylphenol; D000242:Cyclic AMP; D014442:Monophenol Monooxygenase; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase