Tocotrienol monomers and dimers from the roots of Litchi chinensis with tyrosinase inhibition activity

  • Phytochemistry. 2023 Nov 10:217:113921. doi: 10.1016/j.phytochem.2023.113921.
Awat Wisetsai  1 ,  Siwattra Choodej  1 ,  Dina Nur Shinta  1 ,  Sarawut Tontapha  2 ,  Vittaya Amornkitbamrung  2 ,  Paratchata Batsomboon  3 ,  Khanitha Pudhom  4
Affiliations
  • 1. Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
  • 2. Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
  • 3. Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, 54 Kamphaeng Phet 6 Road Laksi, Bangkok, 10210, Thailand.
  • 4. Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand. Electronic address: [email protected].
PMID: 37952709 DOI: 10.1016/j.phytochem.2023.113921
Abstract

Four undescribed modified tocotrienols, including two monomers, litchinols A (1) and B (2), and two walsurol dimers, δ,δ-walsurol (3) and γ,δ-bi-O-walsurol (4), as well as seven known compounds (5-11) were isolated from the roots of Litchi chinensis. The structures of the undescribed compounds were elucidated based on analyses of spectroscopic data and ECD spectra. All tocotrienol derivatives (1-6) were evaluated for their Tyrosinase inhibition activity. Only monomers 1-2 and 5-6 displayed potent inhibitory activity and greater than kojic acid. Kinetic analysis revealed that the representative compound 2 was uncompetitive inhibitor with the inhibition constant value of 5.70 μM.

Keywords
Litchi; Litchi chinensis; Sapindaceae; Tocotrienols; Tyrosinase inhibition.
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