Conclusions
HPLC-DAD-ESI-TOF-MS allowed the identification and quantification
of twenty-eight compounds in olive leaf extracts of
the three cultivars studied. All olive leaf cultivars had contents
of total phenolics, especially ‘Picual’ cultivar, with
oleuropein being the major compound for the three cultivars.
Moreover, this is the first time that the whole phenolic
extracts of olive leaves from olive trees grown in the same experimental
orchard and under the same agronomic and
environmental conditions have been used to in vitro study the
immunomodulatory properties, and it has been shown that they
inhibited the release of the pro-inflammatory mediator NO,
when evaluated in vitro in LPS-stimulated RAW264.7 cells, a macrophage
cell type. Although significant differences existed
among the three olive leaf cultivars for all the compounds and
for total phenols, their respective in vitro activities were nearly
similar. The findings of the present study clearly provide evidence
that support the traditional use of medicinal plants in
the treatment of inflammatory diseases. Further studies in relation
to immunomodulatory and anti-inflammatory potentials
of the extract fractions will be performed in the future