Abstract:
Using HPLC, the seasonal changes in the phenolic co
mpound content of the leaves of
the Gemlik olive cultivar (
Olea europaea
L) has been investigated with respect to the
effects on the alternate bearing of the cultivar. F
or this purpose, the leaf concentrations of
oleuropein, chlorogenic acid, caffeic acid, 3-hydro
xycinnamic acid, scopolin and p-
coumaric acid were analyzed at 10 day intervals aro
und the years. The quantity and
distribution of these phenolics in the leaves showe
d significant differences in 2008 (off
year) and 2009 (on year). In the “on” year, the lev
els of chlorogenic and p-coumaric acids
were high, whereas the abundance of other phenolic
compounds was low. In contrast,
during the “off” year, the chlorogenic and p-coumar
ic acid levels were at low levels,
whereas the levels of the other phenolics were high
. We found a negative relationship
between the chlorogenic acid and caffeic acid conce
ntrations in the “on” and “off” years:
the amount of caffeic acid in the leaves was high,
and the chlorogenic acid level was low.
The contents of chlorogenic acid, caffeic acid, 3-h
ydroxycinnamic acid and p-coumaric
acid were significantly different in the “on” and “
off” years. These findings indicated that
these compounds and the other phenolics examined in
this study were related to alternate
bearing. Interestingly, the levels of all of the ph
enolic compounds examined in this study
were at their highest during the dormant season.
Keywords:
Caffeic acid, Chlorogenic acid, Oleuropein, Olive l
eaves, P-coumaric acid,
Scopolin, 3-hydroxycinnamic acid.
