title: Tyrosinase inhibitors of Pulsatilla cernua root-derived materials.
abstract: The inhibition of mushroom tyrosinase by Pulsatilla cernua root-derived materials was evaluated. The bioactive components of Pulsatilla cernua root were characterized by spectroscopic analyses as 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid, which exhibited potent antityrosinase activity. The ID50 values of 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid were 0.97 and 0.33 mM, respectively. The compounds isolated from Pulsatilla cernua roots exhibited noncompetitive inhibition against oxidation of L-DOPA by mushroom tyrosinase. This activity was compared with that of three cinnamic acid derivatives and four well-known tyrosinase inhibitors. The ID50 of 4-hydroxy-3-methoxycinnamic acid exhibited superior activity relative to anisaldehyde, anisic acid, benzoic acid, benzaldehyde, cinnamic acid, and cinnamaldehyde; but antityrosinase inhibitors and cinnamic acid derivatives, except for cinnamyl alcohol, were slightly more effective than 3,4-dihydroxycinnamic acid. In the case of benzaldehyde and cinnamaldehyde, the aldehyde group is, apparently, a key group in eliciting potent inhibitory activity, whereas anisaldehyde is more effective than anisic acid. Methoxy substitutions, such as 2-methoxycinnamic acid, 3-methoxycinnamic acid, and 4-methoxycinnamic acid, enhanced inhibition of tyrosinase activity. As a naturally occurring tyrosinase inhibitor, 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid may be useful as new agents to inhibit the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) by mushroom tyrosinase.
authors.affiliation: Research Center for Industrial Development of Biofood Materials and Institute of Agricultural and Technology, College of Agriculture, Chonbuk National University, Chonju 561-756, Republic of Korea. hoiseon@moak.chonbuk.ac.kr
authors.forename: Hoi-Seon
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D002109:Caffeic Acids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D003373:Coumaric Acids / Q000737:chemistry / Q000302:isolation & purification; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007980:Levodopa / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000737:chemistry*; D029626:Ranunculaceae / Q000737:chemistry*
chemical_list: D002109:Caffeic Acids; D003373:Coumaric Acids; D004791:Enzyme Inhibitors; D007980:Levodopa; C004999:ferulic acid; D014442:Monophenol Monooxygenase; C040048:caffeic acid