Biology Reference
In-Depth Information
To analyse this fraction, the solvents A:
H
2
O-AcOH (98:2) and B: MeOH-AcOH
(98:2) were employed as mobile phase. The
injection volume was 100 ml and the flow
rate 1.3 ml/min. Under these experimental
conditions a triglycoside of the flavonoid
rutin, named QT, was isolated.
The presence of other flavonoids was
also found in the CH
2
Cl
2
extract of
H. parvi-
florus
; one of them (rt 45.03) has also been
found in the ethanolic extract. The polyphe-
nols present in the CH
2
Cl
2
extract are
thought to contribute to its insecticide activ-
ity (Azcon-Bieto and Talon 1993; Hashim
and Devi, 2003).
result of this evolution, plants have acquired
defence mechanisms against nematodes,
insects, birds and mammals (Jongsma and
Bolter, 1997). It is only when herbivorous
animals can adapt to these defence
mechanisms that they may potentially
become plagues.
The function of cyclotides as plant
defence mechanisms against microorgan-
isms and insects has been mentioned above.
Besides, the anti-alimentary effect of the
ursolic acid on lepidopterous insects, e.g.
Spodoptera litura
(the tobacco plague), has
been reported. b-Sitosterol has also been
demonstrated to have an anti-alimentary
effect. Taking into account these effects, the
insecticidal activity of the extracts and frac-
tions of
H. parviflorus
were investigated. To
this end, the lethal and sublethal effects of
such extracts and fractions were investi-
gated on the fruit fly (
Ceratitis capitata
).
This insect (Fig. 13.3a,b), commonly known
as the Mediterranean fly or fruit fly, is a
worldwide plague, and in Argentina it is
one of the most important plagues of fruit
cultivations, especially those of citrus. This
fly directly affects the fruit during the
maturing process in the tree.
Ceratitis capi-
tata
has a short life cycle, it is easy to
manipulate and has a high fecundity rate,
all features that make it suitable for biologi-
cal assays (Bado
et al
., 2004).
The insecticidal activity of the CH
2
Cl
2
,
50% EtOH, tannin-free ethanolic extracts
and the butanolic and aqueous solutions as
well as the ACN extract were investigated
(Broussalis
et al
., 2010). The concentrations
employed were: CH
2
Cl
2
extract, 1000 and
100 ppm; 50% EtOH extract, 1000 and 100 ppm;
tannin-free 50% EtOH extract and its butanolic
and aqueous solutions, 200 ppm each one;
and ACN extract, 200 ppm. The mortality at
each stage of the life cycle of the fly as well
as the overall mortality was assessed. The
delay in the development of the insect pro-
duced by the CH
2
Cl
2
and 50 % EtOH extracts
was also evaluated (Fig. 13.3c,d,e,f ).
Analysis of variance and Tukey's test
(Steel and Torrie, 1993) were employed as
statistical methods for the analysis of the
results. Dose-response curves were ana-
lysed by probit analysis (Finney, 1971).
13.3.5 Steroidal and triterpenic
compounds:
b
-sitosterol, oleanoic
acid and ursolic acid
The presence of b-sitosterol in the CH
2
Cl
2
extract of
H. parviflorus
was determined by
TLC and gas chromatography (GC) employ-
ing a standard of b-sitosterol. The oleanoic
and ursolic acids were analysed by TLC in
two chromatography systems. The GC analy-
sis of the CH
2
Cl
2
extract of
H. parviflorus
employing standards of oleanoic and ursolic
acid, and the co-chromatography of the extract
employing the corresponding standards,
allowed confirmation of the presence of such
acids in the extract (Broussalis
et al
., 2010).
A wide range of biological and pharma-
cological properties have been reported for
b-sitosterol as well for the oleanic and
ursolic acids, being of great interest for their
therapeutic and industrial uses. The insecti-
cide activity of the CH
2
Cl
2
extract could be
attributed or be reinforced by the anti-
alimentary effect proven for the b-sitosterol
and the oleanic and ursolic acids (Shukla
et al
., 1996; Chandramu
et al.
, 2003;
Mallavadhani
et al
., 2003).
13.4 Insecticide Activity
of
H. parviflorus
Both plants and herbivorous animals have
co-evolved over hundreds of years, and as a
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