title: Dioscin: a synergistic tyrosinase inhibitor from the roots of Smilax china.
abstract: In our study, we investigated the inhibition of mushroom tyrosinase in Smilax china. A methanol (MeOH) extract of S. china was partitioned into hexane, ethyl acetate (EtOAc) and water. Of the three fractions, EtOAc extract showed the strongest inhibition of tyrosinase activity with l-tyrosine or l-DOPA as a substrate. Two compounds were isolated from a final active fraction by activity-guided column chromatography. These compounds were identified as dioscin and oxyresveratrol by comparing their mass, (1)H- and (13)C-NMR spectral data with those reported in the literature. Dioscin showed little inhibition activity of tyrosinase, whereas oxyresveratrol, a known tyrosinase inhibitor, showed a strong tyrosinase inhibitory activity. We discovered that a mixture of oxyresveratrol and dioscin (IC(50)=5.1 and 5.7 μg/ml) highly increased the inhibition of tyrosinase activity with l-tyrosine or l-DOPA as the substrate as compared to either oxyresveratrol (IC(50)=7.8 and 10.9 μg/ml) or dioscin (IC(50)>100 and 100 μg/ml) alone.
authors.affiliation: TKM-Based Herbal Drug Research Group, Korea Institute of Oriental Medicine, Daejeon 305-811, Republic of Korea.
authors.forename: Chun
authors.initials: C
authors.lastname: Liang
authors.forename: Ju-Hwan
authors.initials: JH
authors.lastname: Lim
authors.forename: Seung-Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Dong-Seon
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D004144:Diosgenin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005656:Fungal Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D032281:Smilax / Q000737:chemistry*
chemical_list: D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D010936:Plant Extracts; C019357:dioscin; D014442:Monophenol Monooxygenase; D004144:Diosgenin