Direct Identification and Quantitative Determination of Acidic and Neutral Diterpenes Using 13C-NMR Spectroscopy. Application to the Analysis of Oleoresin of Pinus nigra

We report a methodology that allows identification and quantitative determination of individual acidic and neutral diterpenes in natural mixtures, using the computer-aided analysis of their 13C-NMR spectra. The analytical procedure was validated on artificial mixtures and then applied to authentic oleoresins of Pinus nigra. Up to eleven diterpenes, which represented 63% of the total composition of the oleoresin, were identified and quantified...