title: New constituent from Podocarpus macrophyllus var. macrophyllus shows anti-tyrosinase effect and regulates tyrosinase-related proteins and mRNA in human epidermal melanocytes.
abstract: A new biflavonoid, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5), and five known compounds, (-)-catechin (1), quercetin (2), 2,3-dihydrosciadopitysin (3), sciadopitysin (4), and isoginkgetin (6), were isolated from Podocarpus macrophyllus var. macrophyllus (Podocarpaceae). These compounds were evaluated their ability to inhibit cellular tyrosinase activity and for their melanin inhibitory activity in human epidermal melanocytes (HEMn). In the melanin synthesis assay, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5) showed a potent anti-tyrosinase effect with IC(50)=0.098 mM in HEMn. It also significantly decreased both protein and mRNA levels of the tyrosinase-related protein-2 (TRP-2) by Western blot and quantitative real-time PCR (qRT-PCR) analysis. These findings suggest that the new compound, 2,3-dihydro-4',4'''-di-O-methylamentoflavone (5), is the most active component of P. macrophyllus var. macrophyllus in inhibiting pigmentation and that this inhibition is exerted through inhibition of transcription of the genes encoding TRP2.
authors.affiliation: Department of Biochemistry, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan.
authors.forename: Kur-Ta
authors.initials: KT
authors.lastname: Cheng
authors.forename: Feng-Lin
authors.initials: FL
authors.lastname: Hsu
authors.forename: Shih-Hui
authors.initials: SH
authors.lastname: Chen
authors.forename: Peng-Ke
authors.initials: PK
authors.lastname: Hsieh
authors.forename: Hsu-Shan
authors.initials: HS
authors.lastname: Huang
authors.forename: Ching-Kuo
authors.initials: CK
authors.lastname: Lee
authors.forename: Mei-Hsien
authors.initials: MH
authors.lastname: Lee
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects / Q000201:enzymology*; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012333:RNA, Messenger / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013056:Spectrophotometry, Ultraviolet; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D017931:DNA Primers; D004791:Enzyme Inhibitors; D008543:Melanins; D010936:Plant Extracts; D012333:RNA, Messenger; D013778:Tetrazolium Salts; D013844:Thiazoles; D014442:Monophenol Monooxygenase; C022616:thiazolyl blue