Kushenol A and 8-prenylkaempferol, tyrosinase inhibitors, derived from Sophora flavescens

  • J Enzyme Inhib Med Chem. 2018 Dec;33(1):1048-1054. doi: 10.1080/14756366.2018.1477776.
Jang Hoon Kim  1 ,  In Sook Cho  2 ,  Yang Kang So  1 ,  Hyeong-Hwan Kim  2 ,  Young Ho Kim  3
Affiliations
  • 1. a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Republic of Korea.
  • 2. b Department of Horticultural and Crop Environment , National Institute of Horticultural and Herbal Science, RDA , Wanju , Republic of Korea.
  • 3. c College of Pharmacy , Chungnam National University , Daejeon , Republic of Korea.
PMID: 29873272 DOI: 10.1080/14756366.2018.1477776
Abstract

Tyrosinase is known for an enzyme that plays a key role in producing the initial precursor of melanin biosynthesis. Inhibition of the catalytic reaction of this enzyme led to some advantage such as skin-whitening and anti-insect agents. To find a natural compound with inhibitory activity towards Tyrosinase, the five Flavonoids of kushenol A (1), 8-prenylkaempferol (2), kushenol C (3), formononetin (4) and 8-prenylnaringenin (5) were isolated by column chromatography from a 95% methanol extract of Sophora flavescens. The ability of these Flavonoids to block the conversion of L-tyrosine to L-DOPA by Tyrosinase was tested in vitro. Compounds 1 and 2 exhibited potent inhibitory activity, with IC50 values less than 10 µM. Furthermore, enzyme kinetics and molecular docking analysis revealed the formation of a binary encounter complex between compounds 1-4 and the enzyme. Also, all of the isolated compounds (1-5) were confirmed to possess antioxidant activity.

Keywords
Fabaceae; Sophora flavescens; antioxidant; molecular docking; tyrosinase inhibitor.
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