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Oral magnetic resonance imaging contrast agent based on Ilex paraguayensis herbal extract
Author(s) -
Nestle Nikolaus,
Pauls Sandra,
Wunderlich Arthur
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20837
Subject(s) - manganese , chemistry , relaxometry , contrast (vision) , bioavailability , magnetic resonance imaging , nuclear magnetic resonance , spin echo , medicine , pharmacology , radiology , physics , organic chemistry , optics
In this article we demonstrate the potential of herbal extracts from yerba mate ( Ilex paraguayensis ) as an oral contrast agent for MRI. At typical drinking concentrations, yerba mate acts as a “biphasic” contrast agent with T 1 weighting at short echo times and T 2 weighting at echo times greater than about 40 ms. Based on data obtained from X‐ray fluorescence elemental analysis, NMR relaxometry, and ESR we identify the relaxation agent in the extract as a low‐molecular‐weight manganese complex. Yerba mate exhibits an unusually high manganese content that is readily available for hot water extraction. Despite the high elemental manganese levels in I. paraguayensis extract, no manganese‐related toxicity of yerba mate has been observed even among heavy yerba mate drinkers, indicating that the manganese in the extract has only a very low bioavailability. Imaging results on staff and patient volunteers demonstrate good contrasting of the GI tract. The relaxation studies of the contrast agent show a sensitivity to pH that is consistent with imaging results from stomach and small bowel. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.