Planta Med 2013; 79 - SL14
DOI: 10.1055/s-0033-1351840

Tyrosinase inhibitory compounds from Juglans sigillata Dode

C Si 1, G Xu 2, W Hu 3, L Wu 2, S Liu 2
  • 1a: Tianjin Key Lab of Pulp & Paper, Tianjin Univ of Sci &Technol, China; b: Key Lab of Industrial Fermentation Microbiology of Ministry of Education & Tianjin Key Lab of Industrial Microbiology, Tianjin Univ of Sci & Technol, Tianjin 300457, China
  • 2Tianjin Key Lab of Pulp & Paper, College of Materials Science & Chemical Engineering, Tianjin University of Science &Technology, Tianjin 300457, China
  • 3Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, School of Life Sciences, Huaiyin Normal University, Huaian 223300, China

Tyrosinase is a multifunctional copper-containing polyphenol oxidative enzyme, which is considered to be a key enzyme in melanin synthesis [1]. Some natural compounds with tyrosinase inhibitory activity of plants origin have significant potential to be applied in skin-lightening and depigmenting in the cosmetic field [2]. In this investigation, the phytochemical study, including fractionation and purification, of 70% acetone extract of Juglans sigillata husks led to the isolation of five low molecular weight galloyltannins and their structures were elucidated as 2,3,4,6-tetra-O-galloyl-β-D-glucose (A), 3,4,6-tri-O-galloyl-β-D-glucose (B), 1,2,6-tri-O-galloyl-β-D-glucose (C), tannic acid (D), and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (E) mainly based on their spectral and chemical clues. Compounds A-E showed strong inhibitory activity against mushroom tyrosinase with IC50 values ranging from 35.27 to 76.37 uM, comparing with kojic acid which was used as a positive control with IC50 value of 342.14 uM. It was further found that galloyltannins A-E inhibited melanin production and exhibited intracellular tyrosinase activity, as well as down-regulated mRNA and protein expression levels of tyrosinase in B16F10 mouse melanoma cells. Therefore, the isolated galloyltannins from residues of J. sigillata may serve as potential candidates as remedy for hyperpigmentation and as skin-whitening agents in cosmetics industry.

References:

[1] Shiino M, et al. (2003) Bioorg Chem 31: 129 – 135.

[2] Zocca F, et al. (2010) Bioresour Technol 101: 3791 – 3795.

Acknowledgements: This work was supported by National Natural Science Foundation of China (31000279, 31170541), Natural Science Foundation of Tianjin City (13JCZDJC), Program for New Century Excellent Talents in University (NCET-10 – 0951), Foundation (2012IM002) of Key Lab of Industrial Fermentation Microbiology of Ministry of Education & Tianjin Key Lab of Industrial Microbiology, Tianjin University of Science & Technology, China.