Distinctions among Conifer Exudates by Proton Magnetic Resonance Spectroscopy

Abstract

Proton nuclear magnetic resonance spectra have been recorded of exudates harvested from 12 species from the family Araucariaceae, 40 from the Cupressaceae, and one from the Podocarpaceae. These spectra were compared with the spectra previously recorded of 82 species from the Pinaceae. These four families together represent all major groups of extant, resin-bearing conifers. A common set of 10 COSY two-dimensional cross-peaks generally define samples from the Pinaceae, a different set of six peaks define the Araucariaceae, and yet a third set of 10 peaks define the Cupressaceae, with a few exceptions. It is important that proton spectra can distinguish the Araucariaceae and the Cupressaceae, since carbon-13 spectra do not. The one-dimensional peaks not only confirm these familial distinctions but also often characterize genus and species uniquely.

Chemical Signatures of Fossilized Resins and Recent Plant Exudates

“…Because many modern resins generally are soluble in organic solvents, we also began systematically examining the solution-phase 1 H NMR spectra of conifer resins. [40,41] Such experiments, like non-pyrolytic GC-MS methods, have limitations with regard to sampling. They provide a phenomenological approach to characterizing many types of modern resins quickly.…”

Seasonal Variation and Resin Composition in the Andean Tree Austrocedrus chilensis

“…It is extensively employed to detect differences in chemical composition that can be associated to parameters such as age, sex and mating status [11] to discriminate between sample origin in medicinal and food plants [12] and archaeological samples [13]. Different methods are used to obtain information on chemical constituents of the samples to be analyzed by PCA, including matrix-assisted laser desorption-mass spectrometry (MALDI-MS) [11], surface desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS) [12] and nuclear magnetic resonance (NMR) [14][15][16][17][18]. The terpene composition of gymnosperms has been used to assess the genetic diversity of Pinus and Thuja species [19,20].…”

Resin Diterpenes from Austrocedrus chilensis

“…New techniques used to characterize the resin constituents include gas chromatography coupled to mass spectrometry (GC-MS) [12,13,14,15], and proton magnetic resonance spectroscopy [16]. …”