Radical-scavenging compounds from olive tree (Olea europaea L.) wood

The purpose of this study was to complete knowledge on the chemical composition and radical-scavenging activity of olive tree wood. Two new monoterpene glycosides, (-)-oleuropeic acid 6'-O-α-D-glucopyranosyl ester (6a) and (-)-perillic acid 1'-O-β-D-primeverosyl ester (8), together with the known compounds (-)-oleuropeic acid (1), (-)-olivil (2), the aldehydic form of oleuropein aglycone (3), (+)-1-hydroxypinoresinol 1-O-β-D-glucopyranoside (4), (-)-oleuropeic acid 1'-O-β-D-glucopyranosyl ester (5), (-)-oleuropeic acid 6'-O-β-D-glucopyranosyl ester (6b), and (-)-olivil 4-O-β-D-glucopyranoside (7) were isolated from an ethyl acetate extract. The radical scavengers found (2-4 and 7) were detected and isolated with the help of the online HPLC-DAD-DPPH/ABTS technique. Compounds 2-4 and 7 displayed a higher antioxidative effect against the free radical DPPH than the reference BHT and lower than hydroxytyrosol, whereas compounds 1, 5, 6a, 6b, and 8 showed no activity.

(+)-1-hydroxypinoresinol 1-O-β-d-glucopyranoside; (−)-oleuropeic acid; (−)-oleuropeic acid 1′-O-β-d-glucopyranosyl ester; (−)-oleuropeic acid 6′-O-α-d-glucopyranosyl ester; (−)-oleuropeic acid 6′-O-β-d-glucopyranosyl ester; (−)-olivil; (−)-olivil 4-O-β-d-glucopyranoside; (−)-perillic acid 1′-O-β-d-primeverosyl ester; Olea europaea; agricultural byproducts; aldehydic form of oleuropein aglycone; olive tree wood; online HPLC-DAD-radical-scavenging technique.