Phenolic tyrosinase inhibitors from the stems of Cudrania cochinchinensis.

The phytochemcal profiles of Cudrania cochinchinensis leaf, twig, stem and root were compared by HPLC analysis. It was found that C. cochinchinensis stem extract contained some unknown natural products with potential tyrosinase inhibitory activities. Therefore, the chemical constitutes in extract (95% ethanol) of C. cochinchinensis stem were further investigated in this study. A new racemic mixture, (±)2,3-cis-dihydromorin, and fifteen known phenolic compounds, dihydrokaempferol 7-O-β-d-qlucopyranoside, skimmin, quercetin-7-O-β-d-glucoside, 2,3-dihydroquercetin 7-O-β-d-glucoside, kaempferol-7-O-β-glucopyranoside, quercetin-3,7-di-O-β-d-glucoside, morin-7-O-β-d-glucoside, 1,3,5,8-tetrahydroxyxanthen-9-one, 2,3-trans-dihydromorin, aromadendrin, oxyresveratrol, genistin, protocatechuic acid, kaempferol 3,7-di-O-β-glucopyranoside, and naringenin were isolated. Spectral techniques (MS, (1)H NMR and (13)C NMR) were utilized for their structural identification and their inhibitory activities on mushroom tyrosinase were also evaluated. The results showed that tyrosinase inhibitory activities of (±)2,3-cis-dihydromorin (IC(50) = 31.1 μM), 2,3-trans-dihydromorin (IC(50) = 21.1 μM), and oxyresveratrol (IC(50) = 2.33 μM), were more potent than that of kojic acid (IC(50) = 50.8 μM), a well-known tyrosinase inhibitor, indicating that Cudrania cochinchinensis stem will be a great potential agent for the development of effective natural tyrosinase inhibitors.

[1]  K. Moon,et al.  Inhibitory effects of various antibrowning agents on apple slices , 2001 .

[2]  G. Cordell,et al.  Swertiabisxanthone-I from Swertia macrosperma , 1989 .

[3]  Zunjian Zhang,et al.  Preparative isolation and purification of phenolic acids from Smilax china by high-speed counter-current chromatography , 2008 .

[4]  J. Xu,et al.  Antiinflammatory constituents from the roots of smilax bockii warb. , 2005, Archives of pharmacal research.

[5]  Mingfu Wang,et al.  Chemical components and tyrosinase inhibitors from the twigs of Artocarpus heterophyllus. , 2009, Journal of agricultural and food chemistry.

[6]  T. Mabry,et al.  Carbon-13 NMR studies of flavonoids. III. Naturally occurring flavonoid glycosides and their acylated derivatives , 1978 .

[7]  O. Theander,et al.  Cis- and trans-dihydroquercetin glucosides from needles of Pinus sylvestris , 1988 .

[8]  P. Slade,et al.  Methylation of dihydroquercetin acetates: synthesis of 5-O-methyldihydroquercetin. , 2003, Journal of natural products.

[9]  R. Kondo,et al.  Inhibition of Tyrosinase by Flavonoids, Stilbenes and Related 4-Substituted Resorcinols: Structure-Activity Investigations , 2000, Planta medica.

[10]  M. Nair,et al.  Antioxidant polyphenols from tart cherries (Prunus cerasus). , 1999, Journal of agricultural and food chemistry.

[11]  A. A. Drenin,et al.  New genistein monogalactoside from the aerial part of Trifolium pratense , 2008, Chemistry of Natural Compounds.

[12]  L. Lundgren,et al.  Phenolics from inner bark of Pinus sylvestris , 1996 .

[13]  Qin Zhu,et al.  Tyrosinase inhibitory constituents from the roots of Morus nigra: a structure-activity relationship study. , 2010, Journal of agricultural and food chemistry.

[14]  J. Reisch,et al.  A Furanocoumarin glucoside from stembark of Skimmia japonica , 1992 .

[15]  Encarna Aguayo,et al.  Quality changes and nutrient retention in fresh-cut versus whole fruits during storage. , 2006, Journal of agricultural and food chemistry.

[16]  G. Fonseca,et al.  Effect of L-Ascorbic Acid and Sodium Metabisulfite in the Inhibition of the Enzymatic Browning of Minimally Processed Apple , 2008 .

[17]  Yong Sup Lee,et al.  Identification of tyrosinase inhibitors from Glycyrrhiza uralensis. , 2005, Planta medica.

[18]  I. Kubo,et al.  Flavonols from saffron flower: tyrosinase inhibitory activity and inhibition mechanism. , 1999, Journal of agricultural and food chemistry.

[19]  H. Wichers,et al.  Sequence and Structural Features of Plant and Fungal Tyrosinases , 1997 .

[20]  J. Cassady,et al.  A cytotoxic isoflavone from Cudrania cochinchinensis , 1988 .

[21]  J. Karchesy,et al.  Polyphenolic glycosides from Douglas fir inner bark , 1989 .

[22]  A H Stokes,et al.  Tyrosinase mRNA is expressed in human substantia nigra. , 1997, Brain research. Molecular brain research.

[23]  Francisco Solano,et al.  Hypopigmenting agents: an updated review on biological, chemical and clinical aspects. , 2006, Pigment cell research.

[24]  H. Wichers,et al.  Sequence and structural features of plant and fungal tyrosinases. , 1997, Phytochemistry.

[25]  D. Ferreira,et al.  Circular dichroism, a powerful tool for the assessment of absolute configuration of flavonoids. , 2005, Phytochemistry.

[26]  Mingfu Wang,et al.  Isolation of tyrosinase inhibitors from Artocarpus heterophyllus and use of its extract as antibrowning agent. , 2008, Molecular nutrition & food research.

[27]  A. Vitali,et al.  Two isoflavones and a flavone from the fruits of Maclura pomifera , 1994 .