THE DISTRIBUTION OF DELTA-5 POLYENE ACIDS IN SOME PINE SEED OILS BETWEEN THE ALPHA-CHAINS AND BETA-CHAINS BY C-13-NMR SPECTROSCOPY

Seven Pinus seed oils, previously examined by gas chromatography (Ref. [3]), have been re-examined by C-13-NMR spectroscopy. The spectra clearly indicate the presence of Delta 5 acids (mainly a C-18 Delta 5,9,12 isomer) and almost all the signals have been assigned on the basis of relevant data already in the literature for Delta 5 esters. Using the intensities of appropriate signals it was possible to estimate the level of total Delta 5 acids from signals associated with the C-1, C-2, and glycerol carbon atoms and the level of n-6 acids from the omega 2 and omega 3 signals. The results were in accord with those previously obtained by gas chromatography. The Delta 5 acids were apparent only among the alpha-chains. Taxus baccata seed oil is shown to contain 5,9-18:2, but Delta 5 acids in Chamaecyparis lawsoniana seed oil were too low to be identified by NMR spectroscopy.