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observed upon treatment with the 50%
EtOH extract. Taking into account that the
50% EtOH extract contains cyclotides and
with the aim of determining whether these
compounds were responsible for the insec-
ticidal activity observed, the pre-pupariation
mortality was evaluated employing the 50%
EtOH extract and its corresponding purified
fractions; that is, the tannin-free 50% EtOH
extract and its butanolic and aqueous fractions
and the ACN extract of
H. parviflorus
. Since
the 50% EtOH extract was active at 1000 and
100 ppm, tannin-free and purified fractions
were employed at 200 ppm (Figure 13.6).
All the extracts and fractions induced a
high mortality percentage. However, the
mortality induced by the butanolic fraction
obtained by the purification of the tannin-
free 50% EtOH extract was higher (90%)
than the mortality induced by the aqueous
fraction and the ACN extract. This result is
in agreement with the greater proportion of
cyclotides present in this fraction that dis-
play a high solubility in BuOH. The aque-
ous fraction (65% mortality) and ACN
extract (58% mortality) contain cyclotides
but in smaller quantities, as determined by
HPLC-DAD.
The insecticidal activity of the 50%
EtOH extract, its purified fractions and the
ACN extract that contain cyclotides could
be explained by the observations of Jennings
et al.
(2001) who demonstrated that the
cyclotide Kalata B1 is able to inhibit the
Table 13.2.
Effect of CH
2
Cl
2
and 50% EtOH
extracts at 1000 and 100 ppm on delay in the
development of
Ceratitis capitata
.
Pupariation
time PT
50
(days)
Extract
(ppm)
Confidence
interval
Significant
differences
Control
5.6
5.3-5.7
a
CH
2
Cl
2
(1000)*
-
-
-
CH
2
Cl
2
(100)
5.6
5-6.1
a
50% EtOH
(1000)
11.3
9.8-19.6
b
50% EtOH
(100)
12
10.2-25
b
PT, pupariation time; *<50% of pupariated specimens;
unable to calculate. a,b, significant differences with
respect to control (p <0.05).
Table 13.3.
Effect of extracts on pre-pupariation
mortality of
Ceratitis capitata
.
Extract or
fraction
Significant
differences
Mortality %
Control
0
a
50% EtOH
80
c
Tannin-free
50% EtOH
100
c
BuOH fraction
90
c
Aqueous
fraction
65
b
CAN
58
b
a, b and c, significant differences with respect to control
(p <0.05).
120
a
b
b
100
b
b
80
60
b
b
40
b
b
20
0
Control
CH
2
CI
2
,
1000ppm
CH
2
CI
2
,
100ppm
Extracts and fractions
EtOH 50%,
1000ppm
EtOH 50%,
100ppm
Without puparium formation
Emergence of adults
Without emergence of adults
Overall mortality
Fig. 13.4.
Mortality at each developmental stage and overall mortality. a and b, significant differences
with respect to control (
p
<0.05).
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