Antioxidant Activity and Chemical Composition of Colombian Propolis - Natural Antioxidants and Biocides from Wild Medicinal Plants - page 104

method the formation of complexes between
AlCl 3 with keto and hydroxyl groups is
evaluated at a wavelength of 425 nm
(Kumazawa et al ., 2004). On the other hand,
the quantification of flavanones and dihy-
droflavanones is based on the interaction of
these compounds with 2,4-dinitrophenyl-
hydrazine (DNFH) in acidic medium and
the consequent formation of coloured phe-
nylhydrazones (Popova et al ., 2004).

such as flavonoids and caffeic acids
(Mohammadzadeh et al ., 2007). These classes
of compounds show a wavelength of maxi-
mum absorption of between 240 and 350 nm.

7.4.4 Total phenolic content and total
flavonoid content of propolis from Colombia

Because there are not many studies on the
chemical characterization and antioxidant
activity of propolis from Colombia, we have
performed some analyses in order to evalu-
ate these parameters. We collected samples
from municipalities of two departments
of Colombia: Atlántico, located in the
Caribbean region, and Antioquia, in the
Andean region (Fig. 7.9). The results that
we have achieved were grouped by depart-
ment and are described in the following
sections.

7.4.3 Specific absorbance

of UV spectrum

The 1%

1 c E absorption value is one of the
physicochemical parameters used to evalu-
ate the quality of propolis, because, as was
previously mentioned, most of the activi-
ties of this beehive product are attributed
to the presence of phenolic compounds

Fig. 7.9. Regions of Colombia where propolis samples were collected.