Structure Elucidation and Absolute Configuration Determination of Nortriterpenoids from Picramnia glazioviana

J Nat Prod. 2020 Jun 26;83(6):1859-1875. doi: 10.1021/acs.jnatprod.0c00045. Epub 2020 Jun 12.

Abstract

In this study, HPLC-PDA-HRMS-SPE-NMR data were used for initial analysis of the CH2Cl2 fraction of an EtOH extract of the leaves of Picramnia glazioviana. The HRMS, UV, and NMR data obtained from the HPLC-PDA-HRMS-SPE-NMR analysis were used to direct semipreparative HPLC isolation toward nortriterpenoids, which resulted in the isolation of 18 new and highly oxygenated nortriterpenoids (1-3, 5-10, 12-19, and 21), named picravianes C-T. Their structures were determined on the basis of analysis of UV, HRMS, and 2D NMR spectroscopic data, including determination of the relative configuration on the basis of coupling pattern analysis and nuclear Overhauser effect correlations. The absolute configurations of compounds 7, 9, 10, 14, 15, 17, 18, 19, and 21 were assigned using electronic circular dichroism data, and the cytotoxicity of compounds 6, 10, 14, 16, 17, 18, 19, and 21 was evaluated against MDA-MB-231 triple-negative breast cancer, SKBR-3 Her2-overexpressing breast cancer, and A549 lung cancer cells lines. The isolated compounds contain a hitherto undescribed modification of the terminal backbone and/or E-ring, and a possible biosynthetic pathway for their formation is proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Antineoplastic Agents, Phytogenic / pharmacology
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics
  • Cell Line, Tumor
  • Chromatography, High Pressure Liquid
  • Circular Dichroism
  • Female
  • Humans
  • Lung Neoplasms / drug therapy
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Plant Leaves / chemistry
  • Sapindaceae / chemistry*
  • Solvents
  • Spectrometry, Mass, Electrospray Ionization
  • Spectrophotometry, Ultraviolet
  • Triterpenes / chemistry
  • Triterpenes / isolation & purification

Substances

  • Antineoplastic Agents, Phytogenic
  • Plant Extracts
  • Solvents
  • Triterpenes