Tyrosinase inhibitor isolated from the leaves of Zanthoxylum piperitum.
Two flavonols, quercetin (1) and quercitrin (2), were isolated from the leaves of Zanthoxylum piperitum. Their structures were established by UV, one- and two-dimensional NMR, and mass spectroscopic methods. Quercetin showed significant inhibition against mushroom tyrosinase with an IC50 value of 3.8 microg/ml, and appeared to inhibit the polyphenol oxidase activity of tyrosinase in a competitive manner (Ki = 10 +/- 0.20 microM) when L-tyrosine was used as a substrate, although it did not inhibit the melanin production of Streptomyces bikiniensis.
Jeong
Chang Ho
CH
Division of Applied Life Science, Graduate School and Institute of Agricultural Life Sciences, Gyeongsang National University, JinJu, Korea.
Shim
Ki Hwan
KH
D000363:Agaricales / Q000201:enzymology; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D044948:Flavonols / Q000302:isolation & purification / Q000494:pharmacology; D005656:Fungal Proteins; D020128:Inhibitory Concentration 50; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008543:Melanins / Q000096:biosynthesis; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D018515:Plant Leaves / Q000201:enzymology; D011794:Quercetin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D032106:Zanthoxylum / Q000201:enzymology*
D004791:Enzyme Inhibitors; D044948:Flavonols; D005656:Fungal Proteins; D008543:Melanins; C012526:quercitrin; D011794:Quercetin; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase