title: Rapid, laser-induced conversion of 20-hydroxyecdysone and its diacetonide -- experimental set-up of a system for photochemical transformation of bioactive substances.
abstract: BACKGROUND
  Photochemical transformation of certain bioactive compounds for the purpose of obtaining derivatives with increased bioactivity is a prospective area of synthetic chemistry. Ecdysteroids, analogs of the insect molting hormone, which can also exert several beneficial effects in mammals including humans, contain an enone moiety in their B ring, and, as such, are good candidates for photochemical transformations.
  
  
  METHODS
  20-hydroxyecdysone (20E), the most common ecdysteroid in Nature, and the easily obtained derivative 20-hydroxyecdysone 2,3;20,22-diacetonide (20ED), at different concentrations, were exposed to a 266 nm laser beam at an energy level of 6.5 mJ for different periods of time and evaluated for fluorescence emission during the process of irradiation. The products of irradiation were scanned from 200 to 1500 nm and then subjected to one-dimensional and two-dimensional thin layer chromatography.
  
  
  RESULTS
  During irradiation, progressive significant changes in the fluorescence emission spectra were noted for both compounds with time that were accompanied by changes in their UV-Vis spectra. Full conversion of both compounds was reached within 14 minutes, and both compounds yielded several major products and several minor ones representing a wide polarity range.
  
  
  CONCLUSIONS
  The photo-transformation system described here was proven to be a useful and flexibly adjustable tool for the laser-catalyzed conversion of bioactive compounds. Due to the multi-drug resistance reversal activity of the less polar ecdysteroids, several new products are promising for being tested against various cancer cell lines. Fractionation, isolation and characterization of the irradiated products are currently in process.
authors.affiliation: Institute of Pharmacognosy, Faculty of Pharmacy, University of Szeged, Szeged, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Hunyadi
authors.forename: B
authors.initials: B
authors.lastname: Danko
authors.forename: M
authors.initials: M
authors.lastname: Boni
authors.forename: A
authors.initials: A
authors.lastname: Militaru
authors.forename: T
authors.initials: T
authors.lastname: Alexandru
authors.forename: V
authors.initials: V
authors.lastname: Nastasa
authors.forename: I R
authors.initials: IR
authors.lastname: Andrei
authors.forename: M L
authors.initials: ML
authors.lastname: Pascu
authors.forename: L
authors.initials: L
authors.lastname: Amaral
mesh_terms: D002855:Chromatography, Thin Layer; D004441:Ecdysterone / Q000378:metabolism*; D005453:Fluorescence; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004441:Ecdysterone