Phenolic acids in defatted seeds of borage (Borago officinalis L.)

An ethanolic extract of borage meal was fractionated (fractions I–VI) on a Sephadex LH-20 column. All fractions tested positive for phenolics, but were negative for condensed tannins. Silica gel thin-layer chromatography (TLC) of fractions allowed the location of one and two strong antioxidative spots in fractions I and IV, respectively. Other fractions produced spots containing either weak antioxidative compounds or compounds with low concentrations. High performance liquid chromatography of the three major TLC spots in fractions I and IV showed the presence of one phenolic compound in each spot. Ultraviolet, proton nuclear magnetic resonance and proton-proton correlation spectroscopies, as well as electron impact-mass spectrometry, allowed the identification of three phenolic acids, namely rosmarinic acid in fraction I, and syringic and sinapic acids in fraction IV. These three compounds contributed to 3.9% of the dry mass of the crude extract whereas their total contribution in the meal was 0.6% (w/w).