Journal of Mosquito Research 2015, Vol.5, No.12, 1-7
4
1992) documented that the essential oil obtained from
Vitex negundo
leaves showed repellency ranged from
1 to 3 hour (Hebbalkar et al., 1992). Essential oil
extracted from
Tagetes minuta
, provide 90% protection
for 2 hour against
Ae. aegypti
,
An. stephensi
and
Cx.
quinquefasciatus
(Tyagi et al., 1994). Repellency activity
of methanol extract of
Ferronia elephantum
leaves
against
Ae. aegypti
mosquitoes was reported by
Venkatachalam and Jebanesan (2001). According to
them the extract at 1.0 mg/cm
2
and 2.5 mg/cm
2
concentrations was responsible for 100% protection
up to 2.14±0.16 hour and 4.00±0.24 hour respectively,
while 45.8% and 59.0% protection was achieved up
to10 hours at 1 mg/ cm
2
and 2.5 mg/cm
2
concentrations.
Tawatsin et al., (2001) reported repellency activity of
essential oil of
Curcuma longa
against
Ae. aegypti, An.
dirus
and
Cx. quinquefasciatus
was improved due to
addition of 5% vanillin with it. The same research
group reported repellant activity of essential oils
extracted from 18 other plant species, of 11 families
(Tawatsin et al., 2006). 10% solutions of the oils in
absolute ethanol with additives exhibited excellent
repellency of 4.5-8 hour against night-biting mosquitoes
like
Cx. quinquefasciatus, An. dirus
and
Ae. albopictus
though their effects on
Ae. aegypti
were not so
commendable (0.3-2.8 hour). DEET and ethyl butylact-
ylamino-propionate (IR3535) showed excellent repellency
against
An. dirus
,
Ae. aegypti
,
Ae. albopictus
and
Cx.
quinquefasciatus
(repellency 6.7-8 hour). Amer and
Mehlhorn (2006) described five most effective oils,
Cajeput (
Melaleuca leucadendron
), Litsea (
Litsea
cubeba
), Catnip (
Nepeta cataria
), Niaouli (
Melaleuca
quinquenervia
) and Violet (
Viola odorata
) which
induced 100% repellency against
An. stephensi,
Cx.
quinquefasciatus
and
Ae. aegypti
for 8 hour of
maximum protection time. The essential oil of
Zingiber officinalis
provided 100% protection through
repellent activity at 4.0 mg/ cm
2
up to 120 min against
Cx. quinquefasciatus
(Pushpanathan et al., 2008). It
was revealed from our study that the efficacy of the
ethyl acetate extract of
D. roxburghii
was quite
comparable with the above mentioned study reports
since results showed that 100% protection was
achieved up to 2 hour continuously from 99 %
concentration of the ethyl acetate extract against both
species of mosquitoes. Pandey et al., (2009) described
that the thymol compound isolated from the seed of
Trachyspermum ammi
, at the dose of 25.0 mg/mat
imparted complete repellency for 1 hour duration
against adult form of
An. stephensi
, whereas the same
degree of repellency was obtained by the essential oil
of the seeds at the dose of 55.0 mg/mat. Double-fold
activity of the isolated thymol compound over the oil
was reported in that study. In our study the coils
containing crude extract exhibited complete protection
for 1 hour and the efficiency gradually diminished
with time whereas the 75% and 99% ethyl acetate
extract containing coils conferred 100% protection
from bites of
Cx. quinquefasciatus
and
An. stephensi
with duration of 2 hours. Resemblances of the results
help us to presume that the ethyl acetate extract of the
fruits of
D. roxburghii
was twice as much efficient as
the crude extract of the same as a repellent agent of
mosquitoes. In addition both the extracts had no
adverse effects like allergic manifestations or other
kind of visible reactions during the exposure period or
beyond that.
The plant based products are generally not so expensive,
easily accessible, relatively less toxic to environment
besides being effective on mosquitoes. Entire study
herein clearly demonstrated a high potential for using
crude and ethyl acetate extracts of
D. roxburghii
fruit
as adulticide and repellent against mosquitoe species
like
Cx. quinquefasciatus
and
An. stephensi
without
causing any allergic reaction which may lead to new
and more effective strategies to prevent and control
mosquitoes.
4 Materials and Methods
4.1 Collection of plant material of
D. roxburghii
Mature fruits of
D. roxburghii
were collected from
trees grown within the University campus during
November to January, 20013-2014. It was authenticated
and voucher specimens were deposited in the Mosquito,
Microbiology and Nanotechnology Research Units,
Department of Zoology, The University of Burdwan.
4.2 Preparation of crude extract
Fruits were washed thoroughly with distilled water.
Crude extract was prepared by grinding the plant
material in a mixer grinder. Then the ground material
was passed through cheesecloth. Required concentrations
of crude extract were prepared by mixing the liquid
extract with suitable amount of sterilized distilled water.
4.3 Preparation of solvent extracts
Cleaned mature fruits were dried in shade at room
temperature and milled into fine powder with mixer
