title: Melanin biosynthesis inhibitory and antioxidant activities of quercetin-3'-O-beta-D-glucoside isolated from Allium cepa.
abstract: In the course of searching for new whitening agents, we have found that the methanol extract of dried skin of Allium cepa shows potent melanin biosynthesis inhibitory activity in B16 melanoma cells. Bioassay-guided fractionation led to the isolation of quercetin-3'-O-beta-D-glucoside (1) from the methanol extract of dried skin of A. cepa, which inhibited melanin formation in B16 melanoma cells with an IC50 value of 38.8 microM and mushroom tyrosinase with an IC50 value of 6.5 microM using L-tyrosine and 48.5 microM using L-dihydroxyphenylalanine as substrates, respectively. In addition, the antioxidant activity of 1 was evaluated in the oxygen radical absorbance capacity assay; it showed 3.04 micromol Trolox equivalents/mmol. 1 was shown to be a promising ingredient that could be useful for treating hyperpigmentation and for protecting against oxidative stress.
authors.affiliation: Department of Agro-environmental Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Enos Tangke
authors.initials: ET
authors.lastname: Arung
authors.forename: Shoko
authors.initials: S
authors.lastname: Furuta
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Kondo
mesh_terms: D000490:Allium / Q000737:chemistry*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D005960:Glucosides; D008543:Melanins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D008546:Melanoma, Experimental / Q000473:pathology; D051379:Mice; D011794:Quercetin / Q000031:analogs & derivatives
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D005960:Glucosides; D008543:Melanins; C532085:quercetin 3'-O-glucoside; D011794:Quercetin