title: Phenolic Compounds from the Leaves of Stewartia pseudocamellia Maxim. and their Whitening Activities.
abstract: The half-dried leaves of Stewartia. pseudocamellia were extracted with hot water (SPE) and partitioned with n-hexane (SPEH), dichloromethane (SPED), and ethyl acetate (SPEE) successively. SPE and SPEE showed significant inhibitory effects against melanogenesis and tyrosinase activities. By bioassay-guided isolation, ten phenolic compounds were isolated by column chromatography from SPEE. The whitening effect of the isolated compounds from SPEE were tested for the inhibitory activities against melanogenesis using B16 melanoma cells, in vitro inhibition of tyrosinase, and L-3,4-dihydorxy-indole-2-carboxylic acid (L-DOPA) auto-oxidation assay. A cytotoxic activity assay was done to examine the cellular toxicity in Raw 264.7 macrophage cells. Of the compounds isolated, gallic acid and quercetin revealed significant inhibitory activities against melanogenesis compared to arbutin. In particular, quercetin exhibited similar inhibitory activities against tyrosinase and L-DOPA oxidation without cytotoxicity. These results suggested that SPE could be used as a potential source of natural skin-whitening material in cosmetics as well as in food products.
authors.affiliation: Natural Product Laboratory, School of Pharmacy, Sungkyunkawn University, Suwon 440-746 ; Lifetree Biotech Co. Ltd, Suwon 441-813, Republic of Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Roh
authors.affiliation: Lifetree Biotech Co. Ltd, Suwon 441-813, Republic of Korea.
authors.forename: Hye-Ji
authors.initials: HJ
authors.lastname: Noh
authors.affiliation: Lifetree Biotech Co. Ltd, Suwon 441-813, Republic of Korea.
authors.forename: Chun Su
authors.initials: CS
authors.lastname: Na
authors.affiliation: Natural Product Laboratory, School of Pharmacy, Sungkyunkawn University, Suwon 440-746.
authors.forename: Chung Sub
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Natural Product Laboratory, School of Pharmacy, Sungkyunkawn University, Suwon 440-746.
authors.forename: Ki Hyun
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Lifetree Biotech Co. Ltd, Suwon 441-813, Republic of Korea.
authors.forename: Cheol Yi
authors.initials: CY
authors.lastname: Hong
authors.affiliation: Natural Product Laboratory, School of Pharmacy, Sungkyunkawn University, Suwon 440-746.
authors.forename: Kang Ro
authors.initials: KR
authors.lastname: Lee
keywords: Melanogenesis; Quercetin; Skin whitening; Stewartia pseudocamellia Maxim.; Tyrosinase