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DOI: 10.1055/s-0028-1084650
Carbon-13 CP-MAS NMR studies of some lichens of the Genus Cladonia section Cladina
The solid state 13C CP-MAS NMR (carbon-13 Cross Polarisation Magic Angle Spinning Nuclear Magnetic Resonance) technique has the potential of monitoring the chemical composition in the solid state of an intact plant sample [1,2].
This work shows the application of solid-state NMR in the direct characterization of different lichen species which all originate from the same genus Cladonia (C. portentosa,, C. ciliata f. tenuis, C. arbuscula, C. rangiferina ssp rangiferina, C. mitis) [3]. Indeed all these lichens are hardly differentiated on the basis of botanical characters.
NMR spectra of each solid crushed lichen is obtained and compared to the solid-state NMR spectra of fumarprotocetraric acid, perlatolic acid and (+)-usnic acid [4]. These depsidones and the dibenzofurane usnic acid are major secondary metabolites with unambiguous NMR signals. The peak patterns allow to establish conclusive identification of these lichens with a valuable information on their chemical content.
So, this technique appears to be rapid, non-destructive and relevant for lichen analysis which contain high levels of major compounds for which solubilization difficulties are often encountered.
References: 1. Miglietta, M.L., Lamanna, R. (2006) Magn. Reson. Chem. 44: 675–685.
2. Himmelsbach, D.S. et al. (2000)J. Agric. Food Chem. 48: 1524–1536.
3. Stenroos, S. et al. (2002) Cladistics 18:237–278.
4. Huovinen, K., Ahti, T. (1986) Ann. Bot. Fennici 23:93–106.