Journal of Mosquito Research 2015, Vol.5, No.12, 1-7
3
Table 2
Repellency activity of fruit extracts of
Drypetes roxburghii
against
Culex quinquefasciatus
and
Anopheles stephensi
Type
of
Mosquito
Type of
extract
Conc. (%)
Repellence (%) ±SE
Time period after application of repellent (min)
30 min
60 min
90 min
120 min
150 min
Cx.
quinquefasc
iatus
Ethyl
acetate
1%
5.00±0.57
4.00±0.00
2.00±0.57
0.00±0.00 0.00 ±0.00
25%
79.66±1.45
73.33 ±0.88
52.00±1.54
45.66±0.6
22.33±0.66
50%
100.00±0.00
100.00±0.00
87.66±0.66
83.66±0.66 77.33±0.33
75%
100.00±0.00
100.00±0.00
100.00±0.00
100.00±0.0
90.00±1.00
99%
100.00±0.00
100.00±0.00
100.00±0.00
100±0.00 94.33±0.66
Crude
Fruit juice (100%) 100.00±0.00
100.00±0.00
85.33±0.66
80.00±0.57 73.33±0.88
An. stephensi
Ethyl
1%
8.00±0.57
6.33±0.33
4.33±0.33
2.66±0.33
0.00±0.00
acetate
25%
77.33±0.66
75.66±0.88
53.00±0.57
52.00±1.5
30.00±1.15
50%
100.00±0.00
100.00±0.00
86.0±0.33
84.00±1.15 81.00±0.57
75%
100.00±0.00
100.00±0.00
100.00±0.0
97.33±0.33 92.00±0.57
99%
100.00±0.00
100.00±0.00
100.00±0.0
100.00±0.0
94.00±0.57
Crude
Fruit juice (100%) 100.00±0.00
100.00±0.00
86.33±0.33
84.00±0.57 76.33±0.33
protection was achieved from 99% concentration at
150 minutes after application. In case of
An. stephensi
1% ethyl acetate extract showed 8% repellency at 30
minutes of application but at 150 minutes its
repellency became nil.
3 Discussion
An. stephensi
and
Cx. quinquefasciatus
are the major
vectors of urban malaria and lymphatic filariasis
respectively. Among different methods one of the
approaches for control of these mosquito-borne
diseases is the interruption of disease transmission by
killing or preventing mosquitoes from biting human
beings. Many plant based formulations though have
potential larvicidal activity failed to demonstrate their
adulticidal efficiencies. Lee and Chiang (1994) reported a
good larvicidal property of
Stemona tuberose,
however
found no adulticidal effect. (Choochote et al., 1999)
also tried to demonstrate the adulticidal property of
Kaempferia galanga,
however it only gave a knockdown
effect at the initial stage of exposure but after transferring
to the holding tube, the mosquito restored from the
knocked down state. Therefore they inferred that
perhaps
K. galanga
could be useful as a repellent
instead. However, (Rohani et al.,
1997) reported that
Litsea elliptica
and
Piper aduncum
had potentials as
adulticides against
Ae. aegypti
. (Jeyabalan et al.,
2003)
reported the adulticidal effect of
Pelargonium citrosa
on
An. stephensi
, with LC
50
and LC
90
values of 1.56%
and 5.22% respectively. Similar result was obtained
from root extract of
Valeriana jatamansi
which
established its adulticidal efficacy against
An
.
stephensi
,
An
.
culicifacies
,
Aedes
aegypti
,
An. albopictus
, and
Cx.
quinquefasciatus
(Dua et al., 2008). Results of our
study showed that the crude and ethyl acetate fraction
of
D. roxburghii possessed
marked adulticidal activity
against
Cx. quinquefasciatus
with LC
50
and LC
90
values of 109.62 and 189.01ppm and
against
An.
stephensi
with LC
50
and LC
90
values of 95.41 and
181.96 ppm which were comparable to other reported
botanical formulations having adulticidal activity on
mosquitoes. The Probable cause of exhibiting adulticidal
effect on mosquitoes might be due to the presence of
different secondary metabolites in the fruit extract of
D. roxburghii
. Alkaloids are responsible for toxic
effect in adult mosquitoes if kept in contact or ingested
(Gakuru and Foua, 1996). Flavonoids, saponins are
also reported to be toxic to mosquitoes (Bouchelta et
al., 2005). As the fruits of
D. roxburghii
contain
alkaloids, flavonoids, saponins (Mallick Haldar et al.,
2013), their individual or combined action might be
responsible for causing mortality in mosquitoes as
different compounds involve different mechanisms
of action which reduce the effectiveness of
detoxification mechanism of those compounds
in mosquito (Shama and Dhiman, 1993; Corbel et
al., 2004).
Herbal products with proven potential as repellents
can play an important role in the interruption of the
transmission of mosquito-borne diseases at the individual
as well as at the community level. (Hebbalkar et al.,
