doctoralThesis
Atividades biológicas de extratos salinos de sementes de plantas da caatinga contra Aedes Aegypti e investigação da participação de proteínas bioativas
Fecha
2014-06-09Registro en:
BARBOSA, Patricia Batista Barra Medeiros. Atividades biológicas de extratos salinos de sementes de plantas da caatinga contra Aedes Aegypti e investigação da participação de proteínas bioativas. 2014. 135f. Tese (Doutorado em Bioquímica) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2014.
Autor
Barbosa, Patricia Batista Barra Medeiros
Resumen
Dengue fever, currently the most important arbovirus, is transmitted by the
bite of the
Aedes aegypti
mosquito. Given the absence of a prophylactic vaccine, the
disease can only be controlled by combating the vector insect. However, increasing
reports of resistance and environmental damage caused by insecticides have led to the
urgent search for new safer
alternatives.
Twenty
-
um
plant s
eed extracts from the
Caatinga
were prepared
, tested and
characterized
. Sodium phosphate (
50
mM pH 8.0)
was used as extractor. All extracts showed larvicidal
and
ovipositional deterrence
activity
.
Extracts of
D.
grandiflora,
E. contortisiliquum, A. cearenses
,
C. ferrea
and
C.
retusa
were able to attract females for posture when in low co
ncentration
. In the
attractive concentrations, the CE of
E. contortisiliquum
and
A. cearenses
were
able to
kill 52%
and 100% of the larvae
respectively
. The extracts of
A. cearenses
,
P.
viridiflora, E. velutina,
M. urundeuva
and
S. brasiliensis
were also pupicides, while
extracts of
P. viridiflora, E. velutina,
E. contortisiliquum
,
A. cearenses, A. colubrina,
D.
grandiflora
,
B. cheilantha
,
S. spectabilis, C. pyramidalis,
M. regnelli
e
G. americana
displayed adulticidal activity.
All extracts were toxic to
C. dubia
zooplankton
.
The EB
of
E. velutina
and
E. contortisiliquum
did not affect the viability of fibroblasts
.
In all
extracts were identified at least two potential insecticidal proteins such as enzyme
inhibitors, lectins and chitin
-
binding proteins and components of secondary metabolism
.
Considering all bioassays
, the extracts from
A. cearenses, P. viridiflora, E.
contortisiliquum
,
S. brasiliensis,
E.
velutina
and
M. urundeuva
were considered the
most promising
.
The
E. contortisiliquum
extracts was the only one who did not show
pupicida activity, indicating that its mechanism of action larvicide
and adulticidal
is
related only to the ingesti
on of toxic compounds by insect
,
so it was selected to be
fragmenting.
As observed for the CE
, th
e protein fractions of
E. contortisiliquum
also
showed larvicidal activity, highlighting that F2 showed higher larvicidal activity and
lower en
vironmental toxicity than the CE
source.
The reduction in the proteolytic
activity of larvae fed with crude extra
ct and fractions of
E. contortisiliquum
suggest
ed
that the trypsin inhibitors (
ITEc) would be resp
onsible for larvicidal activity
. However
the increase in the purification of this inhibitor resulted
in loss of larvicidal activity
, but
the absence
of
trypsin inhibitor
reduced the
effectiveness of the fractions
, indicating that
the ITEC contributes to the larvicidal activity of this extract. Not been observed
larvicidal activity and adulticide in rich fraction vicilin, nor evidence of the contribution
o
f this molecule for the larvicidal activity of the extract. The results show the potential
of seeds from plant extracts of Caatinga as a source of active molecules against insects
A. aegypti
at different stages of its development cycle, since they are comp
osed of
different active compounds, including protein nature, which act on different
mechanisms should result in the death of insec