Photohuperzine A-A new photoisomer of huperzine A: structure elucidation, formation kinetics and activity assessment

J Pharm Biomed Anal. 2010 Jun 5;52(2):190-4. doi: 10.1016/j.jpba.2010.01.013. Epub 2010 Jan 20.

Abstract

A new photoisomer of the promising "anti-Alzheimer" drug candidate (+/-) huperzine A is described. The new substance was formed via a photoisomerization reaction and was found to be 1-amino-13-ethylidene-11-methyl-6-aza-tetracyclo-[7.3.1.0(2.7).0(4.7)]-trideca-2,10-diene-5-one using NMR analysis. The kinetics of its formation was studied and proven to be of first-order. The described photoisomer showed a significant loss in activity, being more than 100 times less active than (-) huperzine A itself. The new substance was named photohuperzine A, referring to its photopyridone substructure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids
  • Biological Assay
  • Calibration
  • Cholinesterase Inhibitors / chemistry*
  • Cholinesterase Inhibitors / metabolism*
  • Chromatography, Liquid
  • Kinetics
  • Mass Spectrometry
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Photochemical Processes / radiation effects*
  • Reference Standards
  • Sesquiterpenes / chemistry*
  • Sesquiterpenes / isolation & purification
  • Sesquiterpenes / metabolism
  • Spectrophotometry, Ultraviolet
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • Alkaloids
  • Cholinesterase Inhibitors
  • Sesquiterpenes
  • photohuperzine A
  • huperzine A