Title:Antioxidant Activity and Chemical Components as Potential Anticancer Agents in the Olive Leaf (Olea europaea L. cv Leccino.) Decoction
Volume: 14
Issue: 10
Author(s): Simona De Marino, Carmen Festa, Franco Zollo, Antonella Nini, Lina Antenucci, Gennaro Raimo and Maria Iorizzi
Affiliation:
Keywords:
Antioxidant activity, cancer prevention, decoction, Olea europaea L. cv. leccino, phytochemicals, radical scavenging activity.
Abstract: Epidemiological studies have shown that a reduced risk of chronic diseases such as cancer and cardiovascular diseases is
correlated with a regular consumption of fruits and vegetable, many of which are rich in polyphenols. The additive and synergistic effect
of phytochemicals in fruits and vegetables may reduce chronic diseases related to oxidative stress in human body. Olea europaea L. leaf
are rich in phenolic components, which have been proposed to play a role in cancer prevention. The purpose of this study was to identify
the main components in the Olea europaea L. leaf (cv. Leccino) preserved during the decoction preparation, in order to delineate the
antioxidant activities of the crude extracts and its isolated compounds by using different in vitro assays including DPPH radicalscavenging
capacity, total antioxidant capacity (TAC), xanthine oxidase (XO) inhibitory effect and the ability to delay the linoleic acid
peroxidation process (ALP). The aqueous decoction was partitioned obtaining four extracts and the n-butanol extract showed the highest
antioxidant activity and the highest total phenolic content. Phytochemical investigation leads to the isolation of thirteen secondary
metabolites including simple phenolics, flavonoids, secoiridoids whose structures were elucidated by spectroscopic data (1D and 2D
NMR) and spectrometric techniques. A significant free radical scavenging effect against DPPH has been evidenced in fraxamoside (1)
(EC50 62.6 µM) and taxifolin (5) (EC50 50.0 µM), isolated for the first time from the water decoction. The most active compound in the
TAC evaluation, was the 3,4 dihydro-phenyl glycol (8) (0.90 caffeic acid equiv.) while taxifolin and fraxamoside resulted as the most
efficient inhibitors of XO activity (IC50 2.7 and 5.2 µM, respectively). Secoxyloganin (4), oleuropein (2) and tyrosol (6) showed the
highest ALP activity. This study adds to the growing body of data supporting the bioactivities of phytochemicals and their potential
impact on human health.
