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Brought to light

LMU Munich chemists discover photoreaction in anti-cancer substance

Munich, 04/28/2008

The anti-tumor agent azonafides and its derivates are particularly interesting for cancer therapies of the future because patients treated with them show lower susceptibility to the dreaded condition of multi-drug resistance, or MDR. MDR causes chemotherapy medications to become inactive and is particularly prevalent in some types of leukemia, in some cases necessitating a complete halt to treatment. A further advantage of azonafides-based agents is their ultra-low toxicity. Chemists at Ludwig-Maximilians-Universität (LMU) München have now discovered that the components of the anti-cancer agent undergo dimerization, a reaction where two molecules bond to form a new molecule, under normal daylight conditions. Their findings have now been published in the specialist journal “Chemistry – A European Journal”.

The Organic Chemistry Department under Professor Heinz Langhals synthesized derivates of the substances as precursors of functional dyes for photonics applications and subjected them to systematic analysis. The chemists discovered that the substances underwent a previously unknown photodimerization reaction, where two molecules of the agent bonded in daylight to form a new molecule with completely different dimensions and properties. 

The reaction demonstrated by the chemists has two crucial consequences for cancer treatment. On the one hand, existing medical results must be analyzed and reevaluated in light of the new findings. Since the photodimerization reaction had been previously unknown, the dosage of azonafides-based agents administered in medical tests had been random, depending on the extent to which the substances had been exposed to light during their synthesis, processing and application. On the other hand, the discovery of the dimerization reaction now enables light to be used in a targeted manner to ‘activate’ or ‘deactivate’ active ingredients locally where they are needed”, explains Professor Langhals. While the process opens up completely new areas of potential for cancer treatments, the LMU Munich chemist sees a particularly urgent need to clarify whether the active ingredient is the original material or the product of photodimerization. In the first case, the influence of light causes the concentration of the active ingredient in the drug to decrease; in the second case the active ingredient is itself created by the application of light, without which the drug would be inactive. 


“Anthracene Carboxyimides and Their Dimers (p NA)”,
Heinz Langhals, Gertrud Schönmann, Kurt Polborn,
“Chemistry – A European Journal”, 2008, 14, 5290-5303.
Published online: April 17, 2008,
DOI: 10.1002/chem.200701844


Prof. Dr. Heinz Langhals
Organic Chemistry Department
Tel.: 089 / 2180-77699


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