Phenolic Compounds and Antiradical Scavenging Activity Changes During Borago officinalis Stalk Leaf Development

Abstract

Borage (Borago officinalis) stalk leaves were sampled in the region of Amdoun (north of Tunisia) during their vegetative stage in order to analyze their phenolic composition and to ascertain their antiradical scavenging activity. The harvesting time effect on some physical properties of borage seed were significant. Total phenolic contents ranged from 3.6 mg gallic acid equivalent (GAE) g^-1 DW in young leaves to 4.80 mg gallic acid equivalent (GAE) g^-1 DW in adult leaves. RP-HPLC analysis identified nine phenolic acids during stalk leaf development with the predominance of syringic acid. Total phenolic contents and IC₅₀ values in leaves during their development, allowed to conclude that antioxidant activity does not depend on the high content of total phenolics but on the phenolic composition.