title: Biochemical effects of the flavanol-rich lychee fruit extract on the melanin biosynthesis and reactive oxygen species.
abstract: An ingredient of fruit polyphenol, resveratrol, is known to have an inhibitory effect on melanogenesis. In order to examine the functional differences between resveratrol and other fruit polyphenols, we compared biochemical effects of a resveratrol-free polyphenol, flavanol-rich lychee fruit extract (FRLFE), with other phenolic compounds including resveratrol. FRLFE as well as hydroquinone and resveratrol suppressed growth of B16F1 melanoma cells more significantly than rhododendrol or arbutin. Resveratrol suppressed mushroom tyrosinase at the lowest concentration (23.0 μmol/L) among the compounds tested. FRLFE and hydroquinone suppressed tyrosinase at almost the same concentration (half maximal inhibitory concentration [IC50], 83.5 and 94.6 μmol/L, respectively), which was higher than rhododendrol, ascorbic acid and arbutin (IC50, 245, 345 and 421 μmol/L, respectively). Western blot analysis revealed that although resveratrol decreased expressions of tyrosinase and tyrosinase-related protein 1, FRLFE did not affect their expressions. Both FRLFE and resveratrol suppressed antimycin A-mediated reactive oxygen species (ROS) production in melanocytic cells. Resveratrol-mediated ROS suppression was inhibited by nicotinamide, a SIRT1 inhibitor. However, FRLFE-mediated suppression was not affected by nicotinamide. Moreover, FRLFE directly decreased superoxide in vitro, as detected by superoxide dismutase-like scavenging activity assay. These results suggest that FRLFE can protect melanocytes from cytotoxicity caused by an excess amount of melanin and ROS in a different manner from resveratrol.
authors.affiliation: Department of Dermatology, and Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hagiwara
authors.affiliation: Department of Dermatology, and Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Masae
authors.initials: M
authors.lastname: Okura
authors.affiliation: Department of Dermatology, and Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Sumikawa
authors.affiliation: Department of Dermatology, and Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Tokimasa
authors.initials: T
authors.lastname: Hida
authors.affiliation: Department of Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kuno
authors.affiliation: Department of Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Horio
authors.affiliation: Department of Dermatology, and Pharmacology, Sapporo Medical University School of Medicine, Sapporo, Japan. yamasita@sapmed.ac.jp.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D001104:Arbutin / Q000494:pharmacology; D000440:Butanols / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005638:Fruit; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D032125:Litchi / Q000737:chemistry*; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors; D010088:Oxidoreductases / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077185:Resveratrol; D056564:Sirtuin 1 / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D000440:Butanols; D006873:Hydroquinones; D008543:Melanins; D010936:Plant Extracts; D059808:Polyphenols; D017382:Reactive Oxygen Species; D013267:Stilbenes; C115945:rhododendrol; D000968:Antimycin A; D001104:Arbutin; D010088:Oxidoreductases; C064056:tyrosinase-related protein-1; D014442:Monophenol Monooxygenase; D056564:Sirtuin 1; D000077185:Resveratrol; C031927:hydroquinone
keywords: flavanol-rich lychee fruit extract; melanin; melanocyte; reactive oxygen species; tyrosinase