Effect of harvesting time on phenolic compounds and antiradical scavenging activity of Borago officinalis seed extracts

Borage seeds (Borago officinalis L.) were sampled in Amdoun region (North of Tunisia) during their ripening stage in order to analyse their phenolic compounds and to ascertain their antiradical scavenging activity. The harvesting time effect on some physical properties of borage seed was significant. The increase of dry weight (from 10 to 90%) during ripeness was correlated negatively with that of moisture content (from 90 to 10%). Seed phenolic contents ranged from 2.45 to 10.98 mg GAE/g DW. HPLC analysis permitted to identify nine phenolic acids during seed maturation with the predominance of rosmarinic, syringic and sinapic acids. Total phenolic contents and IC50 values in seed during their maturation, allowed to conclude that antioxidant activity does not depend on the high content of total phenolics but on the phenolic composition.