Monoterpenoid indole alkaloid adducts and dimers from Melodinus fusiformis

Phytochemistry. 2023 Jul:211:113678. doi: 10.1016/j.phytochem.2023.113678. Epub 2023 Apr 12.

Abstract

Eight unprecedented monoterpenoid indole alkaloid (MIA) adducts and dimers, melofusinines A-H (1-8), and three undescribed melodinus-type MIA monomers, melofusinines I-K (9-11), together with six putative biogenetic precursors were isolated from the twigs and leaves of Melodinus fusiformis Champ. ex Benth. Compounds 1 and 2 are unusual hybrid indole alkaloids incorporating an aspidospermatan-type MIA with a monoterpenoid alkaloid unit via C-C coupling. Compounds 3-8 feature the first MIA dimers constructed through an aspidospermatan-type monomer and a rearranged melodinus-type monomer with two different types of couplings. Their structures were elucidated by spectroscopic data, single crystal X-ray diffraction, and calculated electric circular dichroism spectra analysis. In addition, dimers 5 and 8 showed significant neuroprotection effects on MPP +-injured primary cortical neurons.

Keywords: Apocynaceae; Dimeric alkaloids; Melodinus fusiformis Champ. ex benth.; Monoterpenoid indole alkaloids; Neuroprotection effect.

MeSH terms

  • Antineoplastic Agents*
  • Apocynaceae* / chemistry
  • Indole Alkaloids / analysis
  • Indole Alkaloids / pharmacology
  • Molecular Structure
  • Monoterpenes / analysis
  • Plant Leaves / chemistry
  • Secologanin Tryptamine Alkaloids* / chemistry
  • Secologanin Tryptamine Alkaloids* / pharmacology

Substances

  • Monoterpenes
  • Indole Alkaloids
  • Antineoplastic Agents
  • Secologanin Tryptamine Alkaloids