Corymbulosins D-H, 2-Hydroxy- and 2-Oxo-clerodane Diterpenes from the Bark of Laetia corymbulosa

  • J Nat Prod. 2017 Apr 28;80(4):1065-1072. doi: 10.1021/acs.jnatprod.6b01151.
Airi Suzuki  1 ,  Yohei Saito  1 ,  Shuichi Fukuyoshi  1 ,  Masuo Goto  2 ,  Katsunori Miyake  3 ,  David J Newman  4 ,  Barry R O'Keefe ,  Kuo-Hsiung Lee  2  5 ,  Kyoko Nakagawa-Goto  1  2
Affiliations
  • 1. School of Pharmaceutical Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University , Kanazawa 920-1192, Japan.
  • 2. Natural Products Research Laboratories, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-7568, United States.
  • 3. Tokyo University of Pharmacy and Life Sciences , 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
  • 4. NIH Special Volunteer , Wayne, Pennsylvania 19087, United States.
  • 5. Chinese Medicine Research and Development Center, China Medical University and Hospital , 2 Yuh-Der Road, Taichung, 40447, Taiwan.
PMID: 28290698 DOI: 10.1021/acs.jnatprod.6b01151
Abstract

A bioactive CH3OH-CH2Cl2 (1:1) extract of the bark of Laetia corymbulosa provided five new clerodane diterpenes with an isozuelanin skeleton, designated as corymbulosins D-H (1-5), as well as the known corymbulosins B (6) and C (7), for which the relative configurations were not previously determined. The structures of 1-5 were characterized on the basis of 1D and 2D NMR spectroscopic and HRMS analysis. The absolute configurations of all isolated compounds 1-7 were verified through chemical methods, including modified Mosher esterifications or oxidation of the hydroxy group at C-2, ECD experiments, and spectroscopic data comparison. The isolated compounds were evaluated for antiproliferative activity against a small panel of human Cancer cell lines.