Priming effects on phenolics, fatty acids composition, antioxidant, and antibacterial activities of Linum usitatissimum seeds (flaxseed)

The purpose of this study was to evaluate the effect of priming on the biochemical composition (phenolic, total lipid yields, soluble sugars, and starch content), antioxidant and antibacterial activities of flaxseed oil. Five priming methods were used for the purpose including: nonprimed (control), sodium chloride (100 mM osmo-primed), distilled water (hydro-primed), gibberellic acid (4,5 mM, hormonal-primed), and rutin (1 mg/mL). Phenolics, total soluble sugar, starch, lipid yield, and fatty acid composition were measured in these treatments at the end of experiments. Antibacterial activity of flaxseed oil was evaluated against fourteen pathogenic microbial strains using the disk diffusion and the micro-dilution methods. Hydro- or osmo-priming resulted in a reduction in total lipid yields in oleaginous flaxseed. On the other hand, in hormonal priming with GA₃, as well as priming with an antioxidant (rutin), higher lipid content was observed indicating the induction of lipid biosynthesis and/or mobilization of lipid reserves. The levels of soluble sugars and starch content remained unchanged in the seeds primed with NaCl, GA₃ or rutin, whereas they increased by 53% and 14%, respectively, in the hydroprimed seeds. Seed priming enhanced the content of phenolics and flavonoids, and their anti-radical activities. The antibacterial property of flaxseed oils was increased in all seed priming treatments (H₂O, NaCl, GA₃ or rutin) in comparison with nonprimed control treatment as indicated by higher number of strains sensitive to oleaginous flaxseed oil. Our findings showed that the compositional changes in bioactive metabolites and fatty acids induced by seed priming have a profound impact on grain quality of oleaginous flaxseeds and suggest that a similar strategy could potentially be used in increasing the level of target compounds in other pharmaceutical plant species.