Alexander Sturzu, Sumbla Sheikh*, Hubert Kalbacher, Thomas Nägele, Christopher Weidenmaier, Bettina M. Wegenast-Braun, Nadine Schilling, Ulrike Ernemann and Stefan Heckl Pages 723 - 731 ( 9 )
Background: Curcumin has been of interest in the field of Alzheimer’s disease. Early studies on transgenic mice showed promising results in the reduction of amyloid plaques.However, curcumin is very poorly soluble in aqueous solutions and not easily accessible to coupling as it contains only phenolic groups as potential coupling sites. For these reasons only few imaging studies using curcumin bound as an ester were performed and curcumin is mainly used as nutritional supplement.
Methods: In the present study we produced an aminoethyl ether derivative of curcumin using a nucleophilic substitution reaction. This is a small modification and should not impact the properties of curcumin while introducing an easily accessible reactive amino group. This novel compound could be used to couple curcumin to other molecules using the standard methods of peptide synthesis. We studied the aminoethyl-curcumin compound and a tripeptide carrying this aminoethyl-curcumin and the fluorescent dye fluorescein (FITC-curcumin) in vitro on cell culture using confocal laser scanning microscopy and flow cytometry. Then these two substances were tested ex vivo on brain sections prepared from transgenic mice depicting Alzheimer-like β-amyloid plaques.
Results: In the in vitro CLSM microscopy and flow cytometry experiments we found dot-like unspecific uptake and only slight cytotoxicity correlating with this uptake. As these measurements were optimized for the use of fluorescein as dye we found that the curcumin at 488nm fluorescence excitation was not strong enough to use it as a fluorescence marker in these applications. In the ex vivo sections CLSM experiments both the aminoethyl-curcumin and the FITC-curcumin peptide bound specifically to β- amyloid plaques.
Conclusion: In conclusion we successfully produced a novel curcumin derivative which could easily be coupled to other imaging or therapeutic molecules as a sensor for amyloid plaques.
Curcumin, Alzheimer's disease, cytometry, amyloid plaques, confocal laser scanning microscopy, human prostate cancer cell, antibiotics.
Department of Neuroradiology, University of Tubingen, Hoppe-Seyler-Str. 3, 72076 Tubingen, Department of Neuroradiology, University of Tubingen, Hoppe-Seyler-Str. 3, 72076 Tubingen, Interfaculty Institute of Biochemistry, University of Tubingen, Hoppe-Seyler-Str. 4, 72076 Tubingen, Department of Neuroradiology, University of Tubingen, Hoppe-Seyler-Str. 3, 72076 Tubingen, Interfakultaeres Institut fuer Mikrobiologie und Infektionsmedizin, University of Tubingen, DZNE-German Center for Neurodegenerative Diseases, Otfried-Müller-Straße 23, 72076 Tubingen, Institute of Organic Chemistry, University of Tubingen, Auf der Morgenstelle 18, 72076 Tubingen, Department of Neuroradiology, University of Tubingen, Hoppe-Seyler-Str. 3, 72076 Tubingen, Department of Neuroradiology, University of Tubingen, Hoppe-Seyler-Str. 3, 72076 Tubingen