3 RESULTS AND DISCUSSIONS
Phenolic compounds in natural products compose a chemically
heterogeneous group, with approximately 10.000 compounds. The solubility
of phenolic compounds is induced by the polarity of the solvent used,
some of which are soluble only in organic solvents, while others, such
as carboxylic acid and glycosides are solubles in polar solvents
[Miranda et al., 2016]. The content of total polyphenols can vary
according to the different parts of the plant species used, as well as
the type of solvent used in its extraction. The main chemical components
of the artichoke are polyphenols, mainly flavonoids, and their
quantification is extremely important to measure the quality of raw
material in study.
In experiments developed at our laboratory, the presence of total
polyphenols content in the artichoke extract was related, using 2,0 ±
0,2 g EAG/100 g of dry extract. The content of total polyphenols found
in the artichoke crude extract was similar to the values reported in the
literature [Ramaiya, Bujang & Zakaria, 2014]. However, the values
found in the artichoke leaves in our study were higher than those which
were obtained by [Kelly et al, 2013] (0.83 ± 0.07 g EAG/100g) and
less than values found by [Ramaiya, Bujang & Zakaria, 2014] (9.25 g
EAG/100g) even in other plant species, such as P. Edulis . This
divergence can be attributed to the variations between the different
plants, as well as the solvents employed in these studies [Ramaiya,
Bujang & Zakaria, 2014].
On other hand, the determination of total flavonoid demonstrated the
presence of 3,04 mgEQ/100g of extract. According to the same authors,
the efficiency of the extraction depends not only on the polarity of the
solvent used, but on the affinity of the solute for the extraction
solvent, the ratio of the phases and number of extractions.
Due to the instability of the secondary metabolites present in the
artichoke extracts and responsible for their therapeutic activities,
several analytical methods have been developed for the determination and
separation of these compounds. Therefore, the quantification of the
markers is essential to ensure therapeutic efficiency. On other hand,
the analysis of flavonoids levels is extremely important because it is
the precedent for falsifying the extract with caffeoylquinic acids
isolated from other sources, such as from coffee [Botsaris & Alves,
2013].
The caffeoylquinic acids and the flavonoids maintain a production
equilibrium by the plant. An unbalance must be seen with suspicion, as
it is not normal for the plant physiology due to its high levels of
caffeoylquinic acids and low levels of flavonoids, or vice versa. An
adulterated sample, for example, in addition to the absence flavonoids
is doubtful, as previously indicated, the amount of caffeoylquinic acids
in abundance in the extract indicates adulteration, since naturally the
plant does not produce such a high amount of this compound.
Few studies have demonstrated the quantification of equivalents of
flavonoids in quercetin. However, when analyzing 5 commercial samples,
they observed values of flavonoids equivalent in rutina ranging from
46,25 ± 5,83 a 74,13 ± 22,11 mg EQ/100g of extract. In our laboratory,
we demonstrated that the results, despite the different standards used,
it is possible to observe an amount of equivalents flavonoids in
quercetin, 24 times lower than those reported in literature. On the
other hand, the amount of phenolic compounds observed in our laboratory
results was 10 times higher than reference values. The high values of
the phenolic compounds observed in our laboratory results, probably can
be due to presence of caffeoylquinic acids (chlorogenic acid, 1,5
tipfeoylquinic acid and cinarina).
In view of the results, obtaining the dry extract of the artichoke
proved to be effective in preparing a pharmaceutical ingredient and, at
the same time, preserved the characteristics of special metabolites
studied. This drying process consists of pulverization the liquid inside
a chamber, submitted to a controlled air flow, obtaining the ultra-fast
separation of the solids and solubles contained, ending with the
recovery product in prowder.
Despite the discrepancy in the balance of the amount of the flavonoids
and phenolic compounds is evident when compared with the literature.
Additional studies with the quantification of phenolic acids and thin
layer chromatography should be performed to ensure the quality of the
raw material under study.
Thus, the extract presented good values of total polyphenols and
flavonoids with minimal degradation of the quantified metabolites.
The daily intake of flavonoids and total polyphenols can be influenced
mainly by the cultural habits from a certain population, which can lead
to some divergences in relation to the daily concentration ingested
between several populations. [Gary, 2003], reported that the daily
total consumption of flavonoids by the world population can vary between
20 mg/day, in countries like the United States of America, Denmark and
Finland, to 70 mg/day in the Netherlands.
Studies about the estimate intake of flavonoids and polyphenols by the
brazilian population are scarce, where the only information were raised
by [Arabbi Genovese & Zakaria, 2014] and [Miranda et al.,
2016], estimating the intake of approximately 60-106 mg/day of
flavonoids and 377,5 mg/day of polyphenols, respectively.
On the other hand, some studies have shown that the treatment in rats
with flavonoids extracted from grape seed (50 mg/kg/day), in the period
of three weeks, demonstrated a significant result for atherosclerosis
pathology. In this same study, it was observed that the coronary and
aortic flow were recovered, in addition to an improvement in blood
pressure [Giehl et al., 2007]. In some studies involving diabetic
rats, [Vessal, Hemmati & Vasei, 2003] demonstrated that the
administration of two o-heterosides flavonoids, at a concentration of
100 mg/kg, was able to decrease the blood glucose in rats 24 hours after
the treatment. Otherwise, [16] observed the decrease of blood
glucose in treated rats when administered between 10-15 mg/kg of
flavonoid quercetin.
Therefore, the amount of flavonoids and total polyphenols administered
daily to different biological models depends directly on the composition
of the flavonoids. Considering that this concentration can vary between
10 to 100 mg/kg of mass of [Vessal, Hemmati & Vasei, 2003], it was
chosen to work with the administration of 200 mg/kg/day to the animals
treated with artichoke extract.
The monitoring of the animals during the period of three experimental
weeks showed that the diabetic animals presented a feed intake of 28,7±
0,30 g/300g of animal mass, while the non-diabetic animals have ingested
20,4± 0,4 g/300g of animal mass. Otherwise, the water consumption was
equal to 125,1 ± 1,5mL for te diabetic group and 46,1±1,9 g/300g of
animal mass, respectively (Graph 1and 2). Although the observation of an
increase in consumption of water and feed in diabetic animals when
compared to non-diabetic animals, the treatment with the extract was not
able to improve the polydipsia and polyphagia in the diabetic animals
treated with the artichoke extract.
Graph 1. Intake monitoring of feed