γ-linolenic and stearidonic acids from Boraginaceae of diverse Mediterranean origin.

Thirty Boraginaceae species from different tribes were evaluated in a search of γ-linolenic (GLA, 18:3 n- 6)- and stearidonic acid (SDA, 18:4 n- 3)-rich oils. The higher GLA percentages were found in the seed oils of Symphytum bulbosum and S. tuberosum subsp. tuberosum (27.6 and 27.2% of total fatty acids (FA)), which are unusual values for GLA-oils in the current literature. On the whole seed, noticeable GLA percentages were found in S. grandiflorum , S. tuberosum subsp. tuberosum and Borago officinalis (7.43, 4.90, and 4.51 g /100 g, respectively). The main SDA-taxa detected in this study were Buglossoides arvensis, B. incrassata and Glandora oleifolia (21.3, 18.9, and 16.3% of total fatty acids). On total seed weight, Glandora rosmarinifolia showed the highest SDA content (3.57 g/100 g). Finally, the higher FA contents were found in S. grandiflorum and Paramoltkia doerfleri seeds (35.2 and 37.0 g/100 g, respectively). Principal Component Analysis showed that similarities in FA profiles allow grouping species as botanical criteria for Boraginaceae tribes do, while the FA groupings confirm the metabolic activities of desaturase and elongase enzymes. Data on the FA composition of the seed oils analyzed here suggest their potential use as functional foods, and can be considered as novel sources of SDA and GLA.