ArticlePDF Available

Formulation and characterization of garlic (Allium sativum L.) essential oil nanoemulsion and its acaricidal activity on eriophyid olive mites (Acari: Eriophyidae)

Authors:

Abstract and Figures

Green and nanoacaricides including essential oil (EO) nanoemulsions are important compounds to provide new, active, safe acaricides and lead to improvement of avoiding the risk of synthetic acaricides. This study was carried out for the first time on eriophyid mites to develop nanoemulsion of garlic essential oil by ultrasonic emulsification and evaluate its acaricidal activity against the two eriophyid olive mites Aceria oleae Nalepa and Tegolophus hassani (Keifer). Acute toxicity of nanoemulsion was also studied on male rats. Garlic EO was analyzed by gas chromatography–mass spectrometry (GC-MS), and the major compounds were diallyl sulfide (8.6%), diallyl disulfide (28.36%), dimethyl tetrasulfide (15.26%), trisulfide,di-2-propenyl (10.41%), and tetrasulfide,di-2-propenyl (9.67%). Garlic oil nanoemulsion with droplet size 93.4 nm was formulated by ultrasonic emulsification for 35 min. Emulsification time and oil and surfactant ratio correlated to the emulsion droplet size and stability. The formulated nanoemulsion showed high acaricidal activity against injurious eriophyid mites with LC50 298.225 and 309.634 μg/ml, respectively. No signs of nanoemulsion toxicity were noted in treating rats; thus, it may be considered non-toxic to mammals. Stability of garlic oil nanoemulsion, high acaricidal activity, and the absence of organic toxic solvents make the formulation that may be a possible acaricidal product. Results suggest the possibility of developing suitable natural nanoacaricide from garlic oil.
This content is subject to copyright. Terms and conditions apply.
1 23
Environmental Science and Pollution
Research
ISSN 0944-1344
Volume 25
Number 11
Environ Sci Pollut Res (2018)
25:10526-10537
DOI 10.1007/s11356-017-0752-1
Formulation and characterization of
garlic (Allium sativum L.) essential oil
nanoemulsion and its acaricidal activity on
eriophyid olive mites (Acari: Eriophyidae)
Abdel-Tawab H.Mossa, Sahar I.Afia,
Samia M.M.Mohafrash & Badawi
A.Abou-Awad
1 23
Your article is protected by copyright and
all rights are held exclusively by Springer-
Verlag GmbH Germany, part of Springer
Nature. This e-offprint is for personal use only
and shall not be self-archived in electronic
repositories. If you wish to self-archive your
article, please use the accepted manuscript
version for posting on your own website. You
may further deposit the accepted manuscript
version in any repository, provided it is only
made publicly available 12 months after
official publication or later and provided
acknowledgement is given to the original
source of publication and a link is inserted
to the published article on Springer's
website. The link must be accompanied by
the following text: "The final publication is
available at link.springer.com”.
PLANT-BORNE COMPOUNDS AND NANOPARTICLES: CHALLENGES FOR MEDICINE,
PARASITOLOGY AND ENTOMOLOGY
Formulation and characterization of garlic (Allium sativum L.)
essential oil nanoemulsion and its acaricidal activity on eriophyid
olive mites (Acari: Eriophyidae)
Abdel-Tawab H. Mossa
1
&Sahar I. Afia
2
&Samia M. M. Mohafrash
1
&Badawi A. Abou-Awad
2
Received: 23 March 2017 /Accepted: 14 November 2017 /Published online: 27 November 2017
#Springer-Verlag GmbH Germany, part of Springer Nature 2017
Abstract
Green and nanoacaricides including essential oil (EO) nanoemulsions are important compounds to provide new, active,
safe acaricides and lead to improvement of avoiding the risk of synthetic acaricides. This study was carried out for the
first time on eriophyid mites to develop nanoemulsion of garlic essential oil by ultrasonic emulsification and evaluate its
acaricidal activity against the two eriophyid olive mites Aceria oleae Nalepa and Tegolophus hassani (Keifer). Acute
toxicity of nanoemulsion was also studied on male rats. Garlic EO was analyzed by gas chromatographymass spec-
trometry (GC-MS), and the major compounds were diallyl sulfide (8.6%), diallyl disulfide (28.36%), dimethyl
tetrasulfide (15.26%), trisulfide,di-2-propenyl (10.41%), and tetrasulfide,di-2-propenyl (9.67%). Garlic oil nanoemulsion
with droplet size 93.4 nm was formulated by ultrasonic emulsification for 35 min. Emulsification time and oil and
surfactant ratio correlated to the emulsion droplet size and stability. The formulated nanoemulsion showed high acari-
cidal activity against injurious eriophyid mites with LC
50
298.225 and 309.634 μg/ml, respectively. No signs of
nanoemulsion toxicity were noted in treating rats; thus, it may be considered non-toxic to mammals. Stability of garlic
oil nanoemulsion, high acaricidal activity, and the absence of organic toxic solvents make the formulation that may be a
possible acaricidal product. Results suggest the possibility of developing suitable natural nanoacaricide from garlic oil.
Keywords Nanoemulsion .Characterization .Garlic essential oil .Acaricidal activity .Olive orchards .Eriophyidae .Toxicity
Introduction
Synthetic pesticides are widely used in agriculture to control
pest infestations which include several types of pesticides such
as acaricides, insecticides, nematicides, fungicides, herbicides,
molluscicides, rodenticides, and plant growth regulators.
Unfortunately, the widespread use of pesticides is being viewed
with concern because of the possible hazardous effects on the
environmental and human health (Chanda et al. 1997;Abbassy
et al. 2014).
Recently, much attention has been given to studying and
evaluating the acaricidal activity of natural and non-toxic
compounds such as essential oils (EOs) and plant extracts
(Çalmaşur et al. 2006;Mossa2016). These natural com-
pounds or second metabolites are produced by the plant as
plant defense substances to kill or repel pests (Rattan 2010).
Natural compounds are considered as potential sources of new
pesticides that are active against multiple pests, i.e., mites,
insect, nematode, weeds, and fungi (Rhomberg and Wolff
1998; Çalmaşur et al. 2006). They have a different site of
action with multi-mode of action which leads to a wide range
of mechanisms of toxic action (Mossa 2016). Such properties
make it important to use as an alternative to traditional
Responsible editor: Philippe Garrigues
*Abdel-Tawab H. Mossa
abdeltawab.mossa@yahoo.com
1
Pesticide Chemistry Department, National Research Centre (NRC),
33 El Bohouth Street (former El Tahrir St.), Dokki, P.O. 12622,
Giza, Egypt
2
Plant Protection Department, National Research Centre (NRC), 33 El
Bohouth Street (former El Tahrir St.), Dokki, P.O. 12622,
Giza, Egypt
Environmental Science and Pollution Research (2018) 25:1052610537
https://doi.org/10.1007/s11356-017-0752-1
Author's personal copy
pesticides for pest control in integrated pest management
(IPM) and organic farmers (Adil et al. 2015;Burt2004;
Habluetzel et al. 2006; Miresmailli and Isman 2006;Mossa
2016). Triterpene compounds,however, e.g., thymol, citronel-
lal, camphor, 1,8-cineole, α-terpineol, α-pinene, geraniol, cit-
ronellol, citral, limonene, menthone, trans-anethole, linalool,
and piperitone, are considered one of the most active groups
with insecticidal (Choi et al. 2006), acaricidal (Chintkuntla
2015), and fungicidal (Maurhofer and Schl 2007)activities
and others (Adil et al. 2015;Hala2012).
Garlic (Allium sativum L.) was used as an important
healing agent by the ancient Egyptians. Nowadays, garlic
plant is an important Allium species worldwide and the active
compounds of this plant are used as important ingredients in
many foods due to their health and nutritional benefits
(Rattanachaikunsopon and Phumkhachorn 2008). It has been
reported that garlic EO have antimicrobial (Kim et al. 2004),
antioxidant (Mnayer et al. 2014), insecticidal (Yang et al.
2009), and acaricidal activities (Attia et al. 2012). This activity
could be due to the presenceof dipropyl disulfide and dipropyl
trisulfide (Rattanachaikunsopon and Phumkhachorn 2008).
Therefore, garlic extracts and EO can be used as an alternative
to synthetic acaricides due to their acaricidal activity and safe-
ty. Many studies have evaluated the acaricidal activity of gar-
lic extracts or EO against phytophagous mites on host plants
(Attia et al. 2012;Mnayeretal.2014).
On the other hand, olive plantations in the oasis of the
Egyptian Western Desert, Tahrir region, Fayoum, Giza,
Menufiya, Behira, Inshas, and Burg-Elarab have been infested
with different pests of which mites of the family Eriophyidae
proved to be very serious, since they are usually overlooked
because of their small size and not being easily recognized
(International Olive Council 2007). In fact, superfamily
Eriophyoidea is among the most important plant feeding mites
causing damage to cultivated and wild plants. Eriophyid mites
are known as gall, bud, blister, and rust mites. They are basically
wormlike and are from 1/10 (100 μ) to 1/3 (300 μ) mm long
(Jeppson et al. 1975). The small size of their bodies made diffi-
cult to understand, and still challenges attempts to disclose their
secrets. The olive bud mite Aceria oleae Nalepa and olive rust
mite Tegolophus hassani (Keifer) are host-specific and occur
whenever olive trees are cultivated. A. oleae is a small, white in
color, and wormlike species. It is the main acarine pest of all
varieties of olive in the Mediterranean area and is especially
injurious to young trees. Allied species, the olive rust mite,
T. hassani, was found on most of the growing shoots. It sucks
the juice of plant causing yellowish spots on the upper surface of
the leaves. However, these mites twist and deform leaves, cause
fruit misshapen, and seriously reduce the amount and quality of
olives available for pickling (Abou-Awad et al. 2005).
It is of interest to note that the nanotechnology has begun a
new and promising technology to development different pes-
ticides, e.g., acaricides, insecticides, herbicides, nematicides,
and others with different formulations. It has been reported
that most using pesticides are organic compounds with poor
water solubility. So, development of nanoformulations seems
to resolve this main problem and increases the water solubility
of non-polar compounds (Fernandes et al. 2014).
Nanoformulations, however, can enhance pesticide bioavail-
ability and stability without using organic toxic solvents.
In fact, the nanoemulsions are distributions of nanoscale
droplets with droplet size ranging from 20 to 200 nm
(Sugumar et al. 2014). It is one of the most important formu-
lations to improve solubility of natural pesticides such as es-
sential oils without use of organic solvents and development
of environmentally friendly formulations (Wang et al. 2007).
Two methods, high energy and low energy, can be used for
nanoemulsion formulations. Both high pressure and
ultrasonication of the high-energy method can be used as an
emulsification method (Klang et al. 2012; Sugumar et al.
2014). Ultrasonication method is easy to use, economic, and
is considered the most widely used method (Sugumar et al.
2014). Anyway, nanoemulsions of essential oils were devel-
oped by some researchers, such as cinnamon oil (Ghosh et al.
2013), Lamiaceae plant oil (Çalmaşur et al. 2006), eucalyptus
oil (Sugumar et al. 2014), and basil oil (Ghosh 2013). The
objective of this study was carried out to develop
nanoemulsion of garlic essential oil by ultrasonic emulsifica-
tion and evaluate its acaricidal activity against phytophagous
eriophyid olive mites, A.oleaeand T. hassani. Acute toxicity
of nanoemulsion was also studied on male rats.
Materials and methods
Chemicals and reagents
Polysorbate 20 (Tween 20) was obtained from VWR
International 201, Rue CarnotF-94126 Fontenay/Bois,
France. The kits used for biochemical studies of aspartate
aminotransferases (AST; EC 2.6.1.1), alanine aminotransfer-
ases (ALT; EC 2.6.1.2), protein, and albumin were obtained
from Biodiagnostic Company, 29 Tahrir Street, Dokki, Giza,
Egypt. All other chemicals were of reagent grades and obtain-
ed from the local scientific distributors in Egypt.
Essential oil extraction
Garlic cloves, A. sativum L. (500 g), were purchased from a
local market in Giza, Egypt, in October 2016. Cloves were
peeled, crushed, and hydrodistilled by Clevenger apparatus.
The distillation continued until no more condensing oil could
be considered. The essential oil was separated, dried over
anhydrous sodium sulfate (Na
2
SO
4
), transferred to an amber
glass flask, and kept undercooled until use. The yield of the
essential oil was 8.25 g (1.65%).
Environ Sci Pollut Res (2018) 25:1052610537 10527
Author's personal copy
Gas chromatographymass spectrometry analysis
Garlic essential oil constituents were analyzed by a gas chro-
matographymass spectrometry (GC-MS) (Agilent
Technologies) equipped with a gas chromatograph (7890B)
and mass spectrometer detector (5977A) at the Central
Laboratories Network, National Research Centre, Giza,
Egypt. The sample was diluted with hexane (1:19, v/v). The
GC was equipped with a fused silica capillary column (HP-
5MS; 5% phenyl:95% methylpolysiloxane; 30 m × 0.25-mm
internal diameter and 0.25-μm film thickness). Helium was
used as the carrier gas at the rate of 1 ml/min. The GC oper-
ating conditions were as follows: injector volume, 1 μl; split
ratio, 1:30; and injector and detector temperature, 280 and
220 °C, respectively. Column temperature, isothermal at
40 °C for 1 min, was then programmed to rise up to 150 °C
at 4 °C/min; held at this temperature for 6 min, then pro-
grammed to rise up to 210 °C at 4 °C/min; and held at this
temperature for 1 min and ion source temperature, 230 °C.
The effluent of the GC column was introduced directly into
the source of the MS. The MS operating conditions were as
follows: solvent delay time, 3 min; ionization voltage, 70 eV;
and m/zrange, 50550. Identification of different constituents
of garlic oil was determined by comparing the spectrum frag-
mentation pattern with those stored in Wiley and NIST Mass
Spectral Library data.
Nanoemulsion preparation
Oil-in-water nanoemulsion of garlic (A. sativum L.) oil (5%)
was prepared by using Tween 20 as a non-ionic surfactant,
garlic EO, and deionized water. The organic phase (oil and
surfactant) was prepared by adding garlic EO and Tween 20 in
different ratios 1:1, 1:1.1, and 1:1.2 (w/w)(Table1). Then,
aqueous phase (D.W.) was added to organic phase and sub-
jected to sonication for 15, 25, and 35 min using Ultrasonic
(Sonics & Materials, Inc., 53 Church Hill Rd., Newtown, CT,
USA) with a probe diameter of 13 mm at a high frequency of
20 kHz and power output of 750 W. To reduceenergy, ice was
used for cooling during the sonication process and energy was
given through sonicator probe.
Characterization of nanoemulsion
Physicochemical studies
Physicochemical characterization and stability of garlic oil
nanoemulsion to different stress, such as thermodynamics,
centrifugation, heating, cooling, and freeze cycles, were tested
(Shafiq et al. 2006; Ghosh 2013). Firstly, all formulated
nanoemulsions were subjected to centrifugation test. In this
test, formulation nanoemulsions were centrifuged at
10,000 rpm for 30 min at 25 °C using Heraeus Labofuge
400R (Kendro Laboratory Products GmbH, Germany) and
observed for phase separation if any. This method has been
widely used in the stability analysis of nanoemulsion and con-
centrated emulsions (Golemanov et al. 2006). Then, formula-
tions that did not show anyphase separationwere subjected to
the heating-cooling test, which contains 6 cycles between re-
frigerator temperatures at 4 °C for 48 h and 45 °C for 48 h.
Then, formulations that did not show any phase separation
were taken for the freeze-thaw stress test. In this test,
nanoformulations were stored for 2 cycles; each cycle carried
out by stored the nanoemulsion at 20 °C for 48 h and at 25 °C
for 48 h. Finally, the stable formulation nanoemulsions were
stored for 2 months at room temperature in closed tubes for
additional observation like phase separation or creaming. The
observation was carried out every day in the first week,
followed by every week up to 4 months. In this study, two
nanoemulsions (B3 and C3) were stable after physicochemical
test; therefore, droplet size was done on these formulations.
The pH value was measured using the Adwa (AD8000) pH
meter; the pH values of the stable formulation nanoemulsions
were measured at 25 ± 0.1 °C.
Table 1 Chemical compensation of garlic (Allium sativum L.) essential
oil
No RT Area % Compounds
1 5.45 0.25 1,2-Dithiolane
2 5.925 8.6 Diallyl sulfide
3 7.585 1.24 Disulfide, methyl 2-propenyl
4 9.313 0.27 Dimethyl trisulfide
5 13.324 28.36 Diallyl disulfide
6 13.759 0.21 1-Allyl-2-isopropyldisulfane
7 15.367 3.16 Trisulfide, methyl 2-propenyl
8 15.83 4.14 4-Methyl-1,2,3-trithiolane
9 16.162 0.28 (E)-1-(Prop-1-en-1-yl)-2-propyldisulfane
10 18.079 15.26 Dimethyl tetrasulfide
11 18.525 0.21 Propane, 1,1-thiobis[3-(methylthio)-
12 21.117 10.41 Trisulfide, di-2-propenyl
13 21.461 0.26 1-Allyl-3-propyltrisulfane
14 23.006 2.77 5-Methyl-1,2,3,4-tetrathiane
15 23.23 0.26 3-Vinyl-[4H]-1,2-dithiin
16 23.658 4.96 Disulfide, methyl 2-propenyl
17 25.666 0.33 1-(1-(Methylthio)propyl)-2-propyldisulfane
18 27.812 1.55 1,3-Butadiene,3-methyl-1,1-bis(methylthio)-
19 28.676 9.67 Tetrasulfide, di-2-propenyl
20 28.968 0.19 (E)-1-(Prop-1-en-1-yl)-2-propyldisulfane
21 31.886 1.71 4-Methyl-1,2,3-trithiolane
22 39.691 1.88 1-Allyl-3-(2-(allylthio)propyl)trisulfane
23 39.851 1.14 1-(2-Ethyl-[1,3]dithian-2-yl)-3-methyl-butan-1-ol
Rt: retention time (as minutes)
10528 Environ Sci Pollut Res (2018) 25:1052610537
Author's personal copy
Droplet size and zeta potential analysis
The average size, size distribution, and zeta potential
were determined by dynamic light scattering (DLS) in-
strument (PSS, Santa Barbara, CA, USA) at 23 °C,
using the 632-nm line of a HeNe laser as the incident
light with angle 90° and zeta potential with external
angle 18.9°.
The nanoemulsion of 1:1.2 (w/w) ratio of garlic EO
(5%) and Tween 20 with 35-min sonication time was
found to be stable with a lowest droplet size diameter
(93.4 ± 0.532 nm). So, this nanoemulsion (sample C3)
was used for further characterization (zeta potential and
transmission electron microscopy (TEM)) and acaricidal
studies.
TEM
The morphology of the garlic essential oil nanoemulsion was
investigated by transmission electron microscopy (model
JEM-1230, JEOL, Tokyo, Japan). A drop of garlic
nanoemulsion (sample C3) was diluted with deionized water,
transferred into a carbon-coated copper grid, then stained by
phosphotungstic acid solution (2%, pH= 6.7) for 1 min. The
replica was lifted to drying at room temperature (27 °C), and
then, the image was visualized with TEM at 80-kVaccelerat-
ing voltages.
Normal emulsion
Normal emulsion of garlic oil was prepared by using the
sameratioinsampleC3withdifferentsonicationtime.The
emulsion was prepared by using garlic EO (5%) and Tween
20 at ratio of 1:1.2 (w/w) with 5-s sonication time. The
emulsion was unstable after 2 days.
Acaricidal activity of garlic oil nanoemulsion
The acaricidal activity of garlic oil nanoemulsion (sample C3)
was evaluated against the two species of eriophyid mites,
Aceria oleae Nalepa and Tegolophus hassani (Keifer).
Experiments were carried out in the laboratories of plant pro-
tection and pesticide chemistry departments, National
Research Centre (NRC), Egypt.
The olive bud mite A. oleae and the olive rust mite
T. hassani were obtained from abandoned Giza olive nursery,
Faculty of Agriculture, Cairo University. Individual of mite
species were placed on succulent olive leaves at 27± 5 °C, 75
± 5% RH, and 12-h L:D photoperiod.
Clean uninfected succulent olive leaves from terminal
shoots were placed either upper surface or lower surface
downwards on water-saturated cotton in large uncovered
petri disk (15 cm in diameter), ten leaves for every petri
dish, as replicates for each treatment. Due to the difficulty
in transferring the individuals of two eriophyid species,
instead,asmalldiskabout0.25cmindiameterofhost
leaves was carefully examined and the total number of
individuals per disk was recorded before introducing them
the arenas (olive leaves). In this study, 50 mites of
A. oleae or T. hassani were confined on the upper surface
or lower surface per olive leaf was used for experiments,
respectively.
Spraying technique was used to evaluate the toxic ef-
fects of garlic oil nanoemulsion on A. oleae and T. hassani.
Preliminary concentration (400 μg/ml) was selected to es-
timate the range of concentrations of nanoemulsion and
normal emulsion. In the current experiment, different con-
centrations of garlic oil nanoemulsion (150, 200, 300, 400,
and 600 μg/ml) were used on A. oleae, while concentra-
tions of 150, 200, 300, 400, 600, and 800 μg/ml were used
on T. hassani. The same concentrations were used in nor-
mal emulsions. In both mites, control was sprayed by dis-
tilled water. The tested concentrations were sprayed on
both eriophyid species uses a glass atomizer. The volume
of spray solution used for petri dish was calculated based
on petri dish area compared to Fadden area, and 100 l was
considered a volume of spray solution to one Fadden
(100 l/Fadden). Mortality of mites in treatments and con-
trol was recorded after 12, 24, and 48 h of treatment. High
mortality was found after 48 h of treatment; therefore, it
was used in this study. Acaricidal activity was repeated
three times under the same conditions. In the present study,
no mortality was recorded in control mites. However, if
mortality in control mites were less than 5%, we do not
need any corrections. The results were statistically ana-
lyzed by Finney (1971) by using the log-probit software
program Ldp Line® model BEhabsoft^(Bakr 2000). The
toxic index of each compound was calculated by the fol-
lowing equation:
Toxicity index TIðÞ¼LC50or LC90 of nano or normal emulsionðÞ=LC50or LC90 of normal emulsionðÞ½:
The compoundhas TI less than 1 TI n 1ðÞhave high toxicity:
Environ Sci Pollut Res (2018) 25:1052610537 10529
Author's personal copy
Acute toxicity studies
Animals
Male albino rats (Rattus norvegicus)weighing100±5g
were obtained from the Animal Breeding House of the
NRC, Dokki, Giza, Egypt. Rats were kept in polypropyl-
ene cages, with free access standard pellet diet, water ad
libitum, 12-h light/dark cycle, 22 ± 2 °C temperature, and
48% humidity in the laboratory. The rats were acclima-
tized for 1 week before the start of the experiment. All the
rats were kept according to the guidelines and welfare
regarding animal protection approved by NRC Local
Ethical Review Committee and were conducted in accor-
dance with the BGuidefortheCareandUseofLaboratory
Animals^(NRC 2011).
Experimental protocol
Rats were divided into three main groups with two sub-
groups (five rats/sub-group) each, which were used for
acute oral toxicity and biochemical studies. Group (I) re-
ceived distilled water (1 m/rat) and served as a control.
Group II received a single dose of the nanoemulsion of
garlic oil (1 ml/rat) by the oral route; this volume corre-
sponds to 0.5 g garlic oil/kg body weight (average b.wt.
100 g/rat). This dose corresponds to 30 g of garlic oil in
nanoemulsion/person if calculated based on average hu-
man weights (60 kg), which is equivalent to 600 ml of
nanoemulsion/person. Group III received 1 ml/rat of nor-
mal emulsion (5% garlic oil, 6% Tween 20, and 89 ml
water) (Samojlik et al. 2010). In the first three sub-groups,
signs of toxicity and mortality were recorded during the
first 60 min and after 2, 3, and 4 h of oral treatment and
daily for 14 days. Also, food and water consumption were
recorded daily during the experimental period.
In the second sub-group, after oral treatments, rats fasted
overnight and blood samples were collected from the retero-
orbital venousplexus with a fine sterilized glass capillary;
then, rats were sacrificed by cervical dislocation. Blood sam-
ples were left to clot in clean, dry tubes and centrifuged at
3000 rpm (600×g) for 10 min at 4 °C using Heraeus
Labofuge 400R (Kendro Laboratory Products GmbH,
Germany) to obtain the serum. Serum was used for protein,
albumin, AST, and ALT determinations.
Statistical analysis
Data were analyzed using SPSS version 18.0 for Windows,
and the statistical analysis was done by using one-way
ANOVA analysis followed by using post hoc multiple
comparison. The differences were statistically significant at
p< 0.05. All data were expressed as a mean ± standard error
(SE).
Results and discussion
Although the useful role of pesticides was reported in agricul-
ture and public health sectors for increased food and fiber
production and control medical insects, adverse effects were
documented on human, birds, fish, beneficial insects, and eco-
systems (Aktar et al. 2009). Their application caused serious
health effects to human, especially agriculture workers in de-
veloping countries. Every year, the global chronic diseases
and deaths due to pesticide poisoning account 1 million
(Environews Forum 1999). Therefore, research for new and
safe pesticides such as acaricides from natural resources are
very important. It has been reported that EOs are one of the
important sources of natural compounds with acaricidal activ-
ities (Miresmailli and Isman 2006almaşur et al. 2006;
Chintkuntla 2015; Miresmailli and Isman 2006; Laborda
et al. 2013; Han et al. 2011). Moreover, pesticide formulations
contain solvents and other components, which have toxic ef-
fects in addition to active compounds. One problem erected,
when using EO as acaricides, their effects are short lasting
(Sugumar et al. 2014). On the way to solve these problems,
EOs are formulated in nanoemulsions without solvents.
In the present study, essential oil of garlic cloves was ob-
tained by hydrodistillation and the yield was 1.65%. EO was
an analysis by GC-MS, and the chemical compositions of EO
were identified by comparing the MS spectra with those in
Wiley Mass Spectral Library data (Table 1and Fig. 1).
Chemical components of garlic EO are listed in Table 1.The
most prominent compounds found were diallyl sulfide (8.6%),
diallyl disulfide (28.36%), dimethyl tetrasulfide (15.26%), tri-
sulfide, di-2-propenyl (10.41%), tetrasulfide, di-2-propenyl
(9.67%), disulfide, methyl 2-propenyl (4.96%), and trisulfide,
methyl 2-propenyl (3.16%). These compounds about 80.42%
of total garlic EO. Mass spectra and chemical structure of
some major chemical compounds in garlic EO were shown
in Fig. 1. Other components were reported, such as 1,2-
dithiolane, diallyl disulfide, 1,1-thiobis[3-(methylthio)-, and
3-vinyl-[4H]-1,2-dithiin. There are many studies on GC-MS
analysis and chemical compositions of garlic EO
(Rattanachaikunsopon and Phumkhachorn 2008; Dziri et al.
2013; Rao et al. 1999;Kimbarisetal.2006; Gupta et al. 2014;
Naher et al. 2014). GC-MS analysis of garlic EO showed
28.99% diallyl disulfide, 23.22% trisulfide, methyl 2-
propenyl, and 15.36% trisulfide, di-2-propenyl of garlic EO
from Bangladeshi, while 29.12% trisulfide, methyl 2-
propenyl, 21.98% trisulfide, di-2-propenyl, and 17.24%
10530 Environ Sci Pollut Res (2018) 25:1052610537
Author's personal copy
diallyl disulfide of garlic EO from China (Naher et al. 2014). It
has been reported that garlic EO had high percentage (84.3
98.9%) of sulfur compounds, and the major components were
37.3459% diallyl trisulfide, 17.533.6% diallyl disulfide,
and 7.710.4% methyl allyl trisulfide of garlic EO from
Tunisia (Dziri et al. 2013). The constituents of garlic EO from
Egypt were investigatedby GC-MS. The major constituents in
garlic EO were diallyl trisulfide (29.7%), diallyl tetrasulfide
Diallyl sulfide
Diallyl disulphide
Dimethyl tetrasulphide
Trisulfide, di-2-propenyl
Tetrasulfide, di-2-propenyl
Fig. 1 Mass spectra and chemical
structure of major chemical
compounds in garlic essential oil
Environ Sci Pollut Res (2018) 25:1052610537 10531
Author's personal copy
(4.4%), diatlyl disulfide (3.2%), diallyl sulfide (2.5%), and
methyl allyl trisulfide (2.1%) (Jirovetz et al. 1992). The data
obtained by GC-MS analysis of garlic EO are in almost agree-
ment with those reported by previous researchers.
To expect the best ratio of surfactant to be used for garlic oil
nanoemulsion, several formulations of garlic oil (5%) were
prepared by a hydrophilic surfactant polysorbate 20 (Tween
20) and deionized water. The oil and surfactant were used in
different ratios, 1:1, 1:1.1, and 1:1.2 (w/w), and subjected to
different sonication times, 15, 25, and 35 min, by Ultrasonic
(Table 2). All emulsions (A13, B13, and C13) were sub-
jected to different physicochemical and stability studies such
as thermodynamics and centrifugation (Table 3). The formu-
lations (A13, B1, 2, and C1, 2) had an unstable behavior after
stability tests, which showed different degrees of creaming
and separation phase. These formulations were discarded for
additional studies.
Nanoemulsions of 1:1.1 and 1:1.2 (w/w)ratiosofgarlicEO
and Tween 20 with 35-min sonication times were found to be
stable after centrifugation, heating, cooling, and freeze cycles.
After 4 months, the most stable nanoemulsions were B3 and
C3, which showed no phase separation (Table 3). Such droplet
size distribution was measured for these nanoemulsions. The
mean droplet size diameter of B3 nanoemulsion was 98.1 ±
0.553 nm and 90% of the distribution less than 184.4 nm,
while the mean diameter of C3 nanoemulsion was 93.4 ±
0.532 nm and 90% of the distribution less than 171.8 nm
(Fig. 2). Both surfactant concentration and time of sonication
have played an important role in formations of nanoemulsion
and had a direct relation to emulsion stability. Nanoemulsion
of 1:1.2 (w/w) ratio of garlic EO (5%) and Tween 20 with 35-
min sonication time was found to be stable with a lowest
droplet size diameter (93.4 ± 0.532 nm). So, this
nanoemulsion (sample C3) was used for further characteriza-
tion (zeta potential and TEM) and acaricidal studies.
Development of nanoemulsions by oils such as cinnamon oil
(Ghosh et al. 2013), eucalyptus oil (Sugumar et al. 2014), basil
oil (Ghosh et al. 2014), Rosmarinus officinalis (Duarte et al.
2015), and Pterodon emarginatus Vogel oil (Oliveira et al.
2016), and their biological activities were reported.
Morphology and the structure of garlic oil (5%)
nanoemulsion droplets (sample C3) were imagined by trans-
mission electron microscopy (Fig. 3). As shown in this pic-
ture, droplets of formulation nanoemulsion were the spherical
shape and in a good dispersion. This visualization confirmed
the distribution of diameter size of droplets of formulating
nanoemulsion. The same findings were reported by other
studies on nanoemulsions of oils such as cinnamon oil
(Ghosh et al. 2013), neem oil (Anjali et al. 2012), and basil
oil (Ghosh et al. 2014), which is in agreement with our results.
It has been reported that droplets of nanoemulsion have a size
ranging from 20 to 200 nm (Sugumar et al. 2014). Low drop-
let size of nanoemulsions can be found when hydrophile-
lipophile balance (HLB) value of the surfactant couple
Table 3 Physicochemical and
stability studies of formulating
garlic oil nanoemulsions
Sample
code
Sonication time
(min)
Centrifugation Heatingcooling
cycle
Freezethaw
cycle
Result
A1 15 −− x
A2 25 −− x
A3 35 + + x
B1 15 −− x
B2 25 + + x
B3 35 + + +
C1 15 −− x
C2 25 + + x
C3 35 + + +
xfailed, passed
Table 2 Ratio of garlic essential
oil, Tween 20, and deionized
water (w/w) used for preparation
of nanoemulsions
Formulation number Garlic EO:Tween 20 ratio (w/w) Composition in formulations (g)
Garlic EO Tween 20 D.W.
A1:1 5590
B 1:1.1 5 5.5 89.5
C1:1.2 5689
D.W. deionized water
10532 Environ Sci Pollut Res (2018) 25:1052610537
Author's personal copy
coincides with the required HLB value of the oil (Wang et al.
2009;Diazetal.2005; Fernandes et al. 2014; Orafidiya and
Oladimeji 2002).
Zeta potential is a special parameter for studying the stabil-
ity of nanoemulsions. This value is associated with the surface
potential of the droplets (Fernandes et al. 2014). Garlic oil
nanoemulsion (sample C3), in this work, presented zeta
potential value of 31.67 ± 2.4 mV (Fig. 4). Previous investi-
gations reported the high correlation between droplet size, zeta
potential, stability, and attractive forces between droplets
(Tadros et al. 2004). High stability of formulation
nanoemulsions was also correlated with zeta potential values.
Maximum stability of nanoemulsion is detected when zeta
potential value is above ±30 mV (Araújo et al. 2011). The
increase in zeta potential is related to gross forces that exceed
attracting Van der Waals forces, causing in spread particles
and a deflocculated system (Mahdi et al. 2011). This effect
leads to increase the stability of nanoemulsions (Tadros et al.
2004). Stability of nanoemulsion (sample C3) could be due to
the great zeta potential (31.67 mV) and nanodroplet size
(93.4 nm). The correlation between the stability of
nanoemulsion and low droplet diameters (20200 nm) was
reported by other studies (Duarte et al. 2015; Anjali et al.
2012; Oliveira et al. 2016; Salvia-Trujillo et al. 2013; Ghosh
et al. 2013; Mahdi et al. 2011).
The acaricidal activity of nanoemulsion and normal emul-
sion of garlic oil (garlic oil 5% and Tween 20 at ratio 1:1.2)
was evaluated against the two olive species by using spraying
technique. Our results showed that both nanoemulsion and
normal emulsion have the toxic effect to both the two eriophy-
id mites after 48 h of exposure. Table 4shows that individual
of the olive bud mite A. oleae was more sensitive to
nanoemulsion and normal emulsion of garlic oil compared
to the olive rust mite T. hassani. Lethal concentration (LC
50
)
of nanoemulsion and normal emission accounted 298.225 and
584.878 μg/ml against bud mite and 309.634 and 677.830 μg/
ml against rust, respectively. Nanoemulsion have higher mor-
tality on both olive mites compared to normal emission with
toxicity index (TI) 0.51 and 0.457 at LC
50
and 66.7 and 58.8 at
LC
90
against previous mites, respectively. The LC
50
and tox-
icity of nanoemulsion increased by 49% against A. oleae and
by 54.3% against T. hassani,whileLC
90
increased by 66.7
and 58.8% of A. oleae and T. hassani, respectively (Table 4).
The same trend was observed on log concentration probitlines
and concentration-mortality response lines of A. oleae and
T. hassani.
Increase toxicity of nanoemulsion could be due to the in-
creasing in the surface area of emulsion droplets as a result of
nanoemulsion formation (nanodroplet size 93.4 nm). This ef-
fect led to increased biological activity and making garlic oil
nanoemulsion more acaricidal activity than normal emulsion.
Previous studies suggested that the insecticidal activity garlic
EOs can be due to the major components such as dially trisul-
fide, allyl methyl trisulfide, and dimethyl trisulfide (Koul
2004; Swidan 2007). It has been reported that EOs, extracts,
and their components of garlic (Attia et al. 2012;GaraandHill
2000; Wook Kim et al. 2004) and other plants show acaricidal
activity against several phytophagous mites (Pontes et al.
2007; Laborda et al. 2013; Miresmailli and Isman 2006;
Park et al. 2002;El-zemityetal.2006). Previous studies
Sample B3
Sample C3
Fig. 2 Particle size distributionof sample B3 (mean diameter= 98.1 nm)
and sample C3 (mean diameter= 93.4 nm) of garlic oil nanoemulsions
Fig. 3 Transmission electron microscopy (TEM) image of garlic oil
nanoemulsion
Environ Sci Pollut Res (2018) 25:1052610537 10533
Author's personal copy
moreover showed that nanoemulsions of EOs had high toxic-
ity and biological due to chemical and physical properties of
nanodroplets (Rodrigues et al. 2014; Sugumar et al. 2014;
Ribeiro et al. 2014).
To the best of our knowledge, mites of A. oleae were more
sensitive than T. hassani, which had LC
50
298.225 μg/ml
compared to 584.878 μg/ml, respectively. Such individuals
of this species are known as olive buds and leaf mites. The
different sensitivity between the two mites could be due to
seek microenvironments which live, feed, and reproduce.
Other eriophyid allied species insert themselves into crevices
under bud scales or at petiole bases on their host plant, and in
that way gain cover and food and induce growth of galls on
specific plants (Walter and Proctor 1999). In this respect, the
lower sensitivity of T. hassani can be due to their exposure to
environmental stresses.
Really, the highest problems of synthetic pesticides such as
acaricides are the adverse effects on human, non-target organ-
isms, and ecosystems. The toxic effects of these chemical
compounds result from the active ingredients in addition to
the materials and solvents used for formulation. We prepared a
new nanoformulation of garlic EO by using water as the sol-
vent. The acute oral toxicity of this formulation was investi-
gated on male rats, and also, some biochemical parameters
were determined in serum, e.g., albumin, total protein, AST,
and ALT.
Ratsweretreatedwithonesingledoseofgarlicoil,
nanoemulsion and normal emulsion (5%) at dose 0.5-g/kg
Table 4 Toxicity, toxicity index (TI), and percentage of toxicity of nanoemulsion and normal emulsion of garlic (Allium sativum L.) essential
oil on A. oleae and T. hassani
Treatment LC
50
(μg/ml)
LC
50
(μg/ml) Slope LC
90
(μg/ml)
LC
90
(μg/ml)
Lower
limit
Upper
limit
Toxic ity
index (TI)
Percent of
toxicity increase
Lower
limit
Upper
limit
Toxicity
index (TI)
Percent of
toxicity increase
A. oleae
Nanoemul-
sion
298.225 263.176 353.317 0.510 49 2.361 1040.633 716.212 2168.364 0.333 66.7
Normal
emulsion
584.878 471.541 835.207 1 1.761 3125.571 1755.812 9426.787 1
T. hassani
Nanoemul-
sion
309.634 274.074 347.126 0.457 54.3 2.134 1234.154 968.838 1757.030 0.412 58.8
Normal
emulsion
677.830 579.246 843.750 1 1.987 2994.131 2010.075 5601.813 1
LC
50
value represented the concentration of nanoemulsion or normal emulsion, which caused 50% mortality. TI = [(LC
50
or LC
90
of nano or normal
emulsion) / (LC
50
or LC
90
of normal emulsion)]. High toxicity when TI less than 1. Toxicity increase (%) = (TI of normal emulsion TI of
nanoemulsion) × 100
TI: toxicity index,
Fig. 4 Zeta analysis of sample C3
of garlic oil nanoemulsion
10534 Environ Sci Pollut Res (2018) 25:1052610537
Author's personal copy
body weight; this dose corresponds to 30 g of garlic oil
nanoemulsion/person and equivalent to 600 ml of
nanoemulsion/person. Results revealed that there are no mor-
tality and signs of toxicity in rats treated with nanoemulsion
and normal emulsion during the experiment period (14 days).
Water and food consumption and body weight analysis also
indicated an insignificant difference between nanoemulsion
and normal emulsion and control animals (untabulated data).
It has been reported that water and food consumption and
physiological parameters such as body weights are used as
significant criteria for studying the toxicity of pesticides
(Mossa et al. 2015; Mossa et al. 2017).
As we know, the liver is the main organ in the body and
plays an essential role in pesticide detoxification and metabo-
lism. It is the primary target to toxic compounds and their
metabolites. Therefore, liver biomarkers such as albumin, pro-
tein, AST, and ALTwere widely used as bioindicator to study
the toxicity of pesticides in animals and human (Abbassy et al.
2014; Mossa et al. 2017). In this work, nanoemulsion and
normal emulsion did no cause a significant difference in albu-
min and protein levels and AST and ALT activitiesin serum of
male rats (Fig. 5). AST and ALT play an essential role in
catabolism and the biosynthesis of amino acids. They are used
as specific biomarkers for liver damage (Mossa et al. 2015),
and the increase in these enzymes may be due to cell injury
and damage (Goel et al. 2005). Changes in albumin and pro-
tein were also used as an indicator for hepatotoxicity and their
biosynthesis (Mansour and Mossa 2011;MansourandMossa
2009), since no signs of toxicity and mortality and no signif-
icant changes in liver biomarkers were observed in treating
rats. These findings suggest that garlic oil nanoemulsion may
be considered non-toxic. Therefore, our results suggest the
possibility of developing suitable natural acaricide from garlic
oil. Further study is needed to evaluate the effect of garlic oil
nanoemulsion on the predacious mites and their acaricidal
activities under field conditions.
Conclusion
Garlic oil nanoemulsion with droplet size 93.4nm was formu-
lated by ultrasonic emulsification for 35 min. Emulsification
time and oil and surfactant ratio had a correlation with emul-
sion droplet size and stability. The formulated nanoemulsion
showed high acaricidal activity against the two eriophyid olive
mites A. oleae and T. hassani with LC
50
298.225 and
309.634 μg/ml, respectively. Nanoemulsion showed no signs
of toxicity in treating rats, and it may be considered non-toxic
to mammals. Also, the stability of garlic oil nanoemulsion,
high acaricidal activity, and the absence of organic toxic sol-
vents make this formulation a possible acaricidal product. Our
results suggest the possibility of developing suitable natural
nanoacaricide from garlic oil. Further study is needed to eval-
uate the effect of garlic oil nanoemulsion on the predacious
mites and their acaricidal activities under field conditions.
References
Abbassy MA et al (2014) Adverse biochemical effects of various pesti-
cides on sprayers of cotton fields in El-Behira Governorate, Egypt.
Biomed Aging Pathol 4(3):251256
Abou-Awad BA, Metwally AM, A.-A.M. (2005) Environmental man-
agement and biological aspects of two erio-phyid olive mites in
Egypt: Aceria oleae and Tegolophus hassani. Z Pflanzenkrankh
Pflanzenschutz 112(3):287303
Adil B et al (2015) The study of the insecticidal effect of Nigella sativa
essential oil against Tuta absoluta larvae. Int J Sci Technol Res
4(10):8890. Available at: www.ijstr.org. Accessed 15 Nov 2016
Aktar MW, Sengupta D, Chowdhury A (2009) Impact of pesticides use in
agriculture: their benefits and hazards. Interdiscip Toxicol 2(1):1
12. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21217838
[Accessed December 15, 2016]. https://doi.org/10.2478/v10102-
009-0001-7
Anjali C et al (2012) Neem oil (Azadirachta indica) nanoemulsiona
potent larvicidal agent against Culex quinquefasciatus.PestManag
Sci 68(2):158163. https://doi.org/10.1002/ps.2233
Araújo FA, Kelmann RG, Araújo BV, Finatto RB, Teixeira HF, Koester
LS (2011) Development and characterization of parenteral
nanoemulsions containing thalidomide. Eur J Pharm Sci 42(3):
238245. https://doi.org/10.1016/j.ejps.2010.11.014
aa
a
aa
Control Normal Nano
Emulsion
Albumin Protein
a
b
concentraon (mg/dl)
0
1
2
3
4
5
6
7
8
10
20
30
40
50
60
70
80
a
a
a
a
a
a
AST ALT
Control Normal Nano
Emulsion
AST & ALT acvity (U/L)
Fig. 5 Liver dysfunction biomarkers in serum of male rats treated with
nano (nanoemulsion) and normal (normal emulsion) emulsions of garlic
oil. Values are means ± SE, n= 5. Values having the same letters are not
significantly different from each other, p<0.05. ASTs: aspartate amino-
transferases, ALTs: alanine aminotransferases
Environ Sci Pollut Res (2018) 25:1052610537 10535
Author's personal copy
Attia S, Grissa KL, Mailleux AC, Lognay G, Heuskin S, Mayoufi S,
Hance T (2012) Effective concentrations of garlic distillate (Allium
sativum)forthecontrolofTetranychus urticae (Tetranychidae). J
Appl Entomol 136(4):302312. https://doi.org/10.1111/j.1439-
0418.2011.01640.x
Bakr EM (2000) LdP line software. URL: http://www.ehabsoft.com/
ldpline/
Burt S (2004) Essential oils: their antibacterial properties and potential
applications in foodsa review. 94:223253
Çalmaşur Ö, Aslan I, Şahin F (2006) Insecticidal and acaricidal effect of
three Lamiaceae plant essential oils against Tetranychus urticae
Koch and Bemisia tabaci Genn. Ind Crop Prod 23(2):140146.
https://doi.org/10.1016/j.indcrop.2005.05.003
Chanda SM, Mortensen SR, Moser VC, Padilla S (1997) Tissue-specific
effects of chlorpyrifos on carboxylesterase and cholinesterase activ-
ity in adult rats: an in vitro and in vivo comparison. Fundam Appl
Toxicol 38(2):148157
Chintkuntla (2015) Toxicity of plant essential oils to Tetranychus urticae
(Acari: Tetranychidae) and Phytoseiulus persimilis (Acari:
Phytoseiidae). J Econ Entomol 97(2):553558
Choi W, et al. (2006) Fumigant toxicities of essential oils and monoter-
penes against Lycoriella mali adults. 25:398401
Diaz S, Espinosa S, Brignole EA (2005) Citrus peel oil deterpenation with
supercritical fluids optimal process and solvent cycle design.
35(896):4961
Duarte JL, Amado JRR, Oliveira AEMFM, Cruz RAS, Ferreira AM,
Souto RNP, Falcão DQ, Carvalho JCT, Fernandes CP (2015)
Evaluation of larvicidal activity of a nanoemulsion of Rosmarinus
officinalis essential oil. Braz J Pharmacogn 25(2):189192. https://
doi.org/10.1016/j.bjp.2015.02.010
Dziri S et al (2013) Composition of garlic essential oil (Allium sativum L.)
as influenced by drying method. J Essent Oil Res 26(2):9196
El-zemity SR, Rezk HA, Zaitoon AA (2006) Acaricidal activity of some
essential oils and their monoterpenoidal constituents against the par-
asitic bee mites. Varroa Destructor (Acari: Varroidae) 2(11):1032
1036
Environews Forum (1999) Killer environment. Environ Health Perspect
107:A62
FernandesCP, et al. (2014) Development of aninsecticidal nanoemulsion
with Manilkara subsericea (Sapotaceae) extract, 19
Finney DJ (1971) Probit analysis statistical treatment of the sigmoid re-
sponse curve (Book, 1971) WorldCat. Cambridge Univ. Press,
Cambridge
Gara EAO, Hill DJ (2000) Activities of garlic oil, garlic powder, and their
diallyl constituents against Helicobacter pylori. Appl Environ
Microbiol 66(5):22692273
Ghosh V (2013) Formulation and characterization of plant essential oil
based nanoemulsion: evaluation of its larvicidal activity against
Aedes aegypti
. Asian J Chem 25(March):1820
Ghosh V, Saranya S, Mukherjee A, Chandrasekaran N (2013) Cinnamon
oil nanoemulsion formulation by ultrasonic emulsification: investi-
gation of its bactericidal activity. J Nanosci Nanotechnol 13(May):
114122. https://doi.org/10.1166/jnn.2013.6701
Ghosh V, Mukherjee A, Chandrasekaran N (2014) Optimization of pro-
cess parameters to formulate nanoemulsion by spontaneous emulsi-
fication: evaluation of larvicidal activity against Culex
quinquefasciatus larva. BioNanoScience 4(2):157165. https://doi.
org/10.1007/s12668-014-0131-z
Goel A, Dani V, Dhawan DK (2005) Protective effects of zinc on lipid
peroxidation, antioxidant enzymes and hepatic histoarchitecture in
chlorpyrifos-induced toxicity. Chem Biol Interact 156:131140
Golemanov K, Tcholakova S, Denkov ND, Gurkov T (2006) Selection of
surfactants for stable paraffin-in-water dispersions, undergoing
solid-liquid transition of the dispersed particles. Langmuir 22(8):
35603569. https://doi.org/10.1021/la053059y
Gupta R, Sharma A, Maina P, Shukla RN (2014) Study of chemical
composition of garlic oil and comparative analysis of cotrimoxazole
in response toin vitro antibacterial activity. Int Res J Pharm 5(2):97
101. Available at: http://www.irjponline.com/admin/php/uploads/
2110_pdf.pdf.https://doi.org/10.7897/2230-8407.050220
Habluetzel A, et al (2006) Impact of the botanical insecticide Neem Azal
1 on survival and reproduction of the biting louse Damalinia
limbata on angora goats, 110
Hala MI (2012) Activity of essential oil of lemongrass, Chymbopogon
citratus (DC) Stapf against Tetranychus urticae Koch. 3(1):4351
Han J, Kim SI, Choi BR, Lee SG, Ahn YJ (2011) Fumigant toxicity of
lemon eucalyptus oil constituents to acaricide-susceptible and
acaricide-resistant Tetranychus urticae. Pest Manag Sci 67(12):
15831588. https://doi.org/10.1002/ps.2216
International Olive Council (2007) Production techniques in olive grow-
ing. http://www.internationaloliveoil.org/store/view/51-production-
techniques-in-olive-growing-english
Jeppson LR, Keifer HH, Baker EW (1975) Mites injurious to economic
plants. University of California Press. Available at: http://www.
ucpress.edu/op.php?isbn=9780520023819. Accessed 21 Mar 2017
Jirovetz L et al (1992) Investigations of volatile constituents ofthe essen-
tial oil of Egyptian garlic (Allium sativum L.) by means of GC-MS
and GC-FTIR. Z Lebensmittel-Untersuchung Forschung 194(4):
363365
Kim JW et al (2004) Antimicrobial activity of alk(en)yl sulfides found in
essential oils of garlic and onion. Food Sci Biotechnol 13(2):235
239
Kimbaris AC, Siatis NG, Pappas CS, Tarantilis PA, Daferera DJ,
Polissiou MG (2006) Quantitative analysis of garlic (Allium
sativum) oil unsaturated acyclic components using FT-Raman spec-
troscopy. Food Chem 94(2):287295. https://doi.org/10.1016/j.
foodchem.2005.01.017
Klang V, Matsko NB, Valenta C, Hofer F (2012) Electron microscopy of
nanoemulsions: an essential tool for characterisation and stability
assessment. Micron 43(23):85103. https://doi.org/10.1016/j.
micron.2011.07.014
Koul O (2004) Biological activity of volatile di-n-propyl disulfide from
seeds of neem, Azadirachta indica (Meliaceae), to two species of
stored grain pests, Sitophilus oryzae (L.) and Tribolium castaneum
(Herbst). J Econ Entomol 97(3):11421147
Laborda R, Manzano I, Gamón M, Gavidia I, Pérez-Bermúdez P, Boluda
R (2013) Effects of Rosmarinus officinalis and Salvia officinalis
essential oils on Tetranychus urticae Koch (Acari: Tetranychidae).
IndCropProd48:106110. https://doi.org/10.1016/j.indcrop.2013.
04.011
Mahdi ES, Noor AM, Sakeena MH, Abdullah GZ, Abdulkarim MF,
Sattar MA (2011) Formulation and in vitro release evaluation of
newly synthesized palm kernel oil esters-based nanoemulsion deliv-
ery system for 30% ethanolic dried extract derived from local
Phyllanthus urinaria for skin antiaging. Int J Nanomedicine 6:
24992512. https://doi.org/10.2147/IJN.S22337
Mansour SA, Mossa A-TH (2009) Oxidative damage, biochemical and
histopathological alterations in rats exposed to chlorpyrifos and the
antioxidant role of zinc. Pestic Biochem Physiol 96:1423
Mansour SA, Mossa A-TH (2011) Adverse effects of exposure to low
doses of chlorpyrifos in lactating rats. Toxicol Ind Health 27(3):213
224. Available at: http://www.ncbi.nlm.nih.gov/pubmed/20870695.
https://doi.org/10.1177/0748233710384054
Maurhofer M, Schl E (2007) Elsinochrome A production by the bind-
weed biocontrol fungus Stagonospora convolvuli LA39 does not
pose a risk to the environment or the consumer of treated crops.
59:194205
Miresmailli S, Isman MB (2006) Efficacy and persistence of rosemary oil
as an acaricide against two spotted spider mite (Acari:
Tetranychidae) on greenhouse tomato. J Econ Entomol 99(6):
20152023. https://doi.org/10.1093/jee/99.6.2015
10536 Environ Sci Pollut Res (2018) 25:1052610537
Author's personal copy
Mnayer D, Fabiano-Tixier AS, PetitcolasE, Hamieh T, Nehme N, Ferrant
C, Fernandez X, Chemat F (2014) Chemical composition, antibac-
terial and antioxidant activities of six essentials oils from the
Alliaceae family. Molecules 19(12):2003420053. https://doi.org/
10.3390/molecules191220034
Mossa A-TH (2016) Green pesticides: essential oils as biopesticides in
insect-pest management. J Environ Sci Technol 9(5):354378
Mossa ATH, Swelam ES, Mohafrash SMM (2015) Sub-chronic exposure
to fipronil induced oxidative stress, biochemical and
histotopathological changes in the liver and kidney of male albino
rats. Toxicol Rep 2:775784. https://doi.org/10.1016/j.toxrep.2015.
02.009
Mossa A-TH, Abdel Rasoul MA, Mohafrash SMM (2017) Lactational
exposure to abamectin induced mortality and adverse biochemical
and histopathological effects in suckling pups. Environ Sci Pollut
Res 24(11):1015010165
Naher S et al (2014) Comparative studies on physicochemical properties
and GC-MS analysis of essential oil of two varieties of Allium
sativum Linn ( garlic). Int J Pharm Phytopharmacol Res 4(3):173
175
NRCoN, A (2011) Guide for the care and use of laboratory animals. 8th
edn
Oliveira AEMFM et al (2016) Development of larvicidal nanoemulsion
with Pterodon emarginatus Vogel oil. PLoS One 11(1):116
Orafidiya LO, Oladimeji FA (2002) Determination of the required HLB
values of some essential oils. IntJ Pharm 237(12):241249. https://
doi.org/10.1016/S0378-5173(02)00051-0
Park BS et al. (2002) Insecticidal and acaricidal activity of pipernonaline
and piperoctadecalidine derived from dried fruits of Piper longum L.
Crop Protection
Pontes WJT, Oliveira JCG, Câmara CAG, Lopes ACHR, Gondim Júnior
MGC, Oliveira JV, Barros R, Schwartz MOE (2007) Chemical com-
position and acaricidal activity of the leaf and fruit essential oils of
Protium heptaphyllum (Aubl.) Marchand (Burseraceae). Acta
Amazon 37(1):103109. https://doi.org/10.1590/S0044-
59672007000100012
Rao PGP, Rao LJ, Raghavan B (1999) Chemical composition of essential
oils of garlic (Allium sativum L.) J Spices Aromatic Crops 8(1):41
47
Rattan RS (2010) Mechanism of action of insecticidal secondary metab-
olites of plant origin. Crop Prot 29(9):913920. https://doi.org/10.
1016/j.cropro.2010.05.008
Rattanachaikunsopon P, Phumkhachorn P (2008) Diallyl sulfide content
and antimicrobial activity against food-borne pathogenic bacteria of
chives (Allium schoenoprasum). Biosci Biotechnol Biochem
72(11):29872991
Rhomberg LR, Wolff SK (1998) Empirical scaling of single oral lethal
doses across mammalian species based on a large database. Risk
Anal 18(6):741753
Ribeiro JC, Ribeiro WLC, Camurça-Vasconcelos ALF, Macedo ITF,
Santos JML, Paula HCB, Araújo Filho JV, Magalhães RD,
Bevilaqua CML (2014) Efficacy of free and nanoencapsulated
Eucalyptus citriodora essential oils on sheep gastrointestinal nema-
todes and toxicity for mice. Vet Parasitol 204(3-4):243248. https://
doi.org/10.1016/j.vetpar.2014.05.026
Rodrigues E d CR, Ferreira AM, Vilhena JCE, Almeida FB, Cruz RAS,
Florentino AC, Souto RNP, Carvalho JCT, Fernandes CP (2014)
Development of a larvicidal nanoemulsion with Copaiba
(Copaifera duckei) oleoresin. Braz J Pharmacogn 24(6):699705.
https://doi.org/10.1016/j.bjp.2014.10.013
Salvia-Trujillo L, Rojas-Graü MA, Soliva-Fortuny R, Martín-Belloso O
(2013) Effect of processing parameters on physicochemical charac-
teristics of microfluidized lemongrass essential oil-alginate
nanoemulsions. Food Hydrocoll 30(1):401407. https://doi.org/10.
1016/j.foodhyd.2012.07.004
Samojlik I, LakićN, Mimica-DukićN, Đaković-Švajcer K, Božin B
(2010) Antioxidant and hepatoprotective potential of essential oils
of coriander (Coriandrum sativum L.) and caraway (Carum carvi
L.) (Apiaceae). J Agric Food Chem 58(15):88488853. https://doi.
org/10.1021/jf101645n
Shafiq S et al (2006) Development and bioavailability assessment of
ramipril nanoemulsion formulation. Eur J Pharm Biopharm 66(2):
227243
Sugumar S et al. (2014) Nanoemulsion ofeucalyptus oil and its larvicidal
activity against Culex quinquefasciatus.393402
Swidan MH (2007) Effect of garlic oil and allyl disulfide on protein and
amino acid composition of two stored-product adult insects
Callosobruchus chinensis (Coleoptera: Bruchidae) and Sitophilus
oryzae (Coleoptera: Curculionidae). Sci J Fac Sci Minu-a Univ
XXI:91113
Tadros T et al (2004) Formation and stability of nano-emulsions. Adv
Colloid Interf Sci 108109:303318
Walter DE, Proctor HC (1999) Mites: ecology, Evolution, and Behaviour.
UNSW Press, Sydney
Wang L, Dong J, Chen J, Eastoe J, Li X (2009) Design and optimization
of a new self-nanoemulsifying drug delivery system. J Colloid
Interface Sci 330(2):443448. https://doi.org/10.1016/j.jcis.2008.
10.077
Wang L, Li X, Zhang G, Dong J, Eastoe J (2007) Oil-in-water
nanoemulsions for pesticide formulations. J Colloid Interface Sci
314(1):230235. https://doi.org/10.1016/j.jcis.2007.04.079
Yang FL, Li XG, Zhu F, Lei CL (2009) Structural characterization of
nanoparticles loaded with garlic essential oil and their insecticidal
activity against Tribolium castaneum (Herbst) (Coleoptera:
Tenebrionidae). J Agric Food Chem 57(21):1015610162. https://
doi.org/10.1021/jf9023118
Environ Sci Pollut Res (2018) 25:1052610537 10537
Author's personal copy
... [29] Additionally, garlic EO nanoemulsion and thymus oil have shown effectiveness against eriophyid olive mites (A. oleae Nalepa, and Tegolophus hassani Keifer) [30] and mango leaf coating mite (Cisaberoptus kenyae Keifer) respectively. [31] However, whether these EOs are effective against other eriophyid mites is unclear and many of the attributes of plant EOs are still unexplored. ...
... The results of the current study support earlier studies that showed the various eriophyid species, including A. guerreronis, could be successfully controlled by using EOs of some aromatic and medicinal plants; [28] that A. oleae and T. hassani could be controlled by a garlic oil nanoemulsion; [30] and that C. kenyae could be controlled by EO from Thymus vulgaris L. [31] The various literature has extensively examined the insecticidal and acaricidal properties of EEO. [27,42,[53][54][55] Several investigators have also documented significant acaricidal effects of EEOs on different mite species. ...
Article
Plant‐derived essential oils (EO) offer natural alternative to chemical pesticides for eco‐friendly pest control approaches. Aceria pongamiae Keifer, a notorious pest that affects Pongamia pinnata (L.) Pierre has mainly been controlled using synthetic acaricides leading to resistance development and environmental issues. EOs provide natural biodegradable option for pest control with unique mode of action. Study evaluates acaricidal efficacy of EOs‐eucalyptus Eucalyptus maculata Hook (EEO), lavender Lavandula angustifola L. (LEO), peppermint Mentha piperita L. (PEO) and black pepper Piper nigrum L. (BPEO) against A. pongamiae for the first time. Biological activity of EOs using fumigation and contact toxicity assays at concentrations ranging from 0.1 to 1% and 0.6 to 0.9% respectively, overexposure periods of 24, 48 and 72h was investigated. Chemical characterization was performed using GC‐MS analysis. Eucalyptol (62.88%), linalyl acetate (39.11%), menthol (44.35%) and caryophyllene (32.77%) were the main components of EEO, LEO, PEO and BPEO respectively. After 24h observation, EEO (LC50=1.01%) and after 48 and 72h, PEO had the highest fumigant toxicity (LC50=0.71 and 0.29% respectively). The BPEO showed the most contact toxicity after 24, 48 and 72h (LC50=0.92, 0.68 and 0.46% respectively). This work reinforces the selection of adequate essential oils for implementation in future pest control strategies.
... NE has been shown to be effective at increasing the antimicrobial and insecticidal activities of essential oils against bacteria and blowflies (Da et al. 2018;Velho et al. 2021). Garlic oil nanoemulsions exhibit stability and high acaricidal activity and are nontoxic to mammals (Mossa et al. 2018). ...
... Due to the instability of the microemulsion system, stabilization was required during the whole storage period. Mossa et al. (2018) revealed that the drop size and stability of nanoemulsions were correlated with emulsification time and ingredient ratio. In this study, the MCEO-NE particles exhibited a regular spherical shape, uniformly distributed drop size, and stable morphology, similar to the findings of Velho et al. (2021). ...
Article
Full-text available
Moutan Cortex essential oil (MCEO) is considered to be a promising botanical insecticide. However, like most oils, MECO has several limitations, including instability and poor solubility. Nanoencapsulation technology is an excellent strategy for stabilizing essential oils because of its controlled release, enhanced efficacy, and strengthened biological activity. The present study investigated the acaricidal efficacy of pure MCEO and its encapsulated nanoemulsion (NE) and mesoporous silica nanoparticles (MSNs) against the house dust mite Dermatophagoides farinae using contact bioassays, fumigant bioassays, repellent bioassays, and the observation of toxic symptoms. MCEO-MSNs obtained in the study successfully encapsulated MCEO with an encapsulation efficiency of 63.83%. The acaricidal mortality experiments revealed that MCEO-NE and MCEO-MSN showed more significant toxicity against D. farinae than did pure MCEO. The nanomaterials showed better larvicidal and nymphicidal activities than pure MCEO at a high concentration (12-h LC90). Notably, the repellent effect experiment showed that MCEO-NE and MCEO-MSN had long-term and stable repellent effects on D. farinae, indicating the sustained release and persistence of the nanomaterials. More toxicity symptoms were observed in the IM-type group than in the KD-type group, suggesting that the MCEO nanoparticles have adverse effects on the respiratory system. Nanomaterials and MCEO promoted superoxide dismutase (SOD) activity and inhibited acetylcholinesterase (AChE) activity in D. farinae. In addition, the binding sites of paeonol to SOD and AChE were found through molecular docking. These findings demonstrate the potential of MCEO as a biological acaricide, which merits further investigation.
... Nanoemulsion-based delivery systems have been suggested to improve the physico-chemical characteristics of EOs by lowering volatility, increasing stability, increasing water solubility, and shielding them from environmental interaction (Bilia et al., 2014;Odriozola-Serrano et al., 2014and Samar et al 2021. Plant extracts or essential oils in nanoformulations are thought to be harmless for humans and the environment (Mossa et al., 2018). The goal of this study is to evaluate a novel P. graveolens nanoemulsion and study its insecticidal effectiveness against the wheat weevil, S. oryzae, under laboratory conditions. ...
Article
Full-text available
Nano-formulation of Pelargonium graveolens essential oil was studied to improve its utilization, efficacy, and stability and its effect against (Sitophilus oryzae L.). P. graveolens nanoemulsion was prepared utilizing a high-energy ultra-sonication process and characterized by transmission electron microscopy (TEM). The average of droplets size found 30.99 nm, and the morphology of the droplets formed a spherical shape. Also, a higher zeta potential value of 50.8 mV results in a more stable. Furthermore, the accelerated stability of the optimized nano-formulations provided acceptable results under preparation conditions. There were no significant changes in the physical characteristics of the formulation. The bioassays results indicated that P. graveolens nanoemulsion provided the lower LC50 value 2.298 ppm/cm2, indicating a higher toxicity level, while the free oil value was 67.66 ppm/cm 2. S. oryzae mortality increased with increasing exposure intervals and concentration rate when adults were exposed to treated wheat grains. However, increasing the exposure interval increased adult mortality. Progeny emergence six weeks after exposure to this beetle was generally low and after three months decreased with increasing concentration. These findings suggest that P. graveolens nanoemulsion was encourage the use of P. graveolens nanoemulsion in pest control systems for stored products, as well as the development of environmentally friendly materials and long-lasting control agents.
... Indeed, almost 100% mortality of larvae exposed to the treatments was achieved at the two highest-tested concentrations. The efficacy of garlic EO against crop pests has already been assessed against other insect pest groups, such as Hemiptera [23], Lepidoptera [26,31], Isoptera [32], Coleoptera ( [33,34]), Mallophaga [35], and Diptera [36], as well as against other arthropods, such as Acari [16]. On the other hand, few studies on garlic EO or extracts applied as insecticides against S. littoralis. ...
Article
Full-text available
Spodoptera littoralis, commonly known as the Egyptian or African cotton leafworm, is a significant agricultural threat. It is widely distributed in Africa, Mediterranean Europe, and Middle Eastern countries. This polyphagous pest infests numerous crop plants across 44 families, including cotton, soybeans, alfalfa, sweet potato, pepper, eggplant, tomato, maize, lettuce, strawberry, wheat, and hibiscus. The damage caused by S. littoralis on different plant organs, such as young leaves, shoots, stalks, bolls, buds, and fruits, often determines substantial product losses. Current control strategies predominantly rely on synthetic insecticides, which, despite their efficacy, have notable drawbacks, including insecticide resistance, environmental contamination, consumer concerns, and adverse effects on non-target organisms and beneficial insects. In response to these challenges, in this study, we developed and evaluated a garlic EO-based nanoemulsion with a high EO concentration (15%) and low surfactant content to mitigate the possible negative impact on plants and to enhance efficacy against S. littoralis larvae. Laboratory bioassays demonstrated promising larvicidal activity and reduced larval feeding, although some phytotoxicity symptoms were observed. This study underscores the potential of botanical insecticides as sustainable alternatives to synthetic chemicals, emphasizing the importance of balancing efficacy with environmental and ecological considerations in pest management strategies.
Article
Nanoemulsions are dispersions of oil-in-water (O/W) and water-in-oil (W/O) immiscible liquids. Thus, our main goal was to formulate a nanoemulsion with low surfactant concentrations and outstanding stability using Copaiba balsam oil (Copaifera sp.). The high-energy cavitation homogenization with low Tween 80 levels was employed. Then, electrophoretic and physical mobility properties were assessed, in addition to a one- and two-year physicochemical characterization studies assessment. Copaiba balsam oil and nanoemulsions obtained caryophyllene as a major constituent. The nanoemulsions stored at 4 ± 2 °C exhibited better physical stability. Two years after formulation, the nanoemulsion showed a reduction in the particle size. The size underwent changes in gastric, intestinal, and blood pH, and the PdI was not changed. In FTIR, characteristic bands of sesquiterpenes and overlapping bands were detected. When subjected to freezing and heating cycles, nanoemulsions did not show macroscopic changes in higher concentrations. Nanoemulsions subjected to centrifuge force by 1000 rpm do not show macroscopic instability and phase inversion or destabilization characteristics when diluted. Therefore, the nanoemulsion showed stability for long-term storage. The nematode Caenorhabditis elegans was used to assess the potential toxicity of nanoemulsions. The nanoemulsion did not cause toxicity in the animal model, except in the highest concentration tested, which decreased the defecation cycle interval and body length. The toxicity and stability outcomes reinforce the nanoemulsions’ potential for future studies to explore pharmacological mechanisms in superior experimental designs.
Article
Full-text available
The ecotoxicological consequences of synthetic pesticides have encouraged stakeholders to search for eco-friendly pest control tools, like essential oils (EOs). Nano-delivery systems (nanoparticles and nano-emulsions) seem ideal for developing EO-based biopesticides, although production processes should be standardized and implemented. In this study, nano-emulsions loaded with a high amount of Allium sativum L. EO (15%) were developed using different mixed bottom-up/top-down processes. Garlic EO was chemically analyzed by gas chromatography-mass spectrometry (GC-MS) and formulations were physically characterized using Dynamic Light Scattering (DLS) apparatus. The insecticidal activity against Planococcus citri Risso (Hemiptera: Pseudococcidae) and selectivity toward Apis mellifera L. (Hymenoptera: Apidae) worker bees was evaluated. Garlic EO was mainly composed of sulphur components (96.3%), with diallyl disulphide and diallyl trisulphide as the most abundant compounds (37.26% and 28.15%, respectively). Top-down processes could produce stable nano-emulsions with droplet size in the nanometric range (< 200nm) and good polydispersity index (PDI < 0.2). In contrast, the bottom-up emulsion was unstable, and its droplet size was around 500nm after 24 hours. High-energy emulsification processes significantly increased the residual toxicity of garlic EO against 3rd instar P. citri nymphs, whereas the developed formulations were harmless to A. mellifera workers in topical application. This study confirmed that the production process significantly affected the physical properties and efficacy against target pests. The lack of adverse impact on honeybees denotated the potential of these formulations as bioinsecticides in organic and/or IPM programs, although further extended ecotoxicological studies are necessary.
Article
Agro-industrial co-products, such as fish gelatin, stand out for their capacity in forming biopolymeric films, being biocompatible and non-toxic; however, its hydrophilicity poses a challenge. Essential oils, rich in bioactives, attract research interest aiming to enhance the protective barrier of films and enable their application in packaging. This study produced films based on cross-linked Nile tilapia skin gelatin, incorporating garlic essential oil. Gelatin obtained through partial collagen hydrolysis from the fish skin and cross-linked with gallic acid had hydroxyproline content of 10.02 g 100 g− 1 and gel strength of 287 g, which were consistent with other studies. Oil extraction used supercritical CO2 as a solvent and ethanol as a cosolvent, following a factorial experimental design, evaluating the extraction temperature (40 ◦C and 70 ◦C) and cosolvent ratio (1:1 and 1:3), with three central points. Extraction was successful, with higher yields on a dry basis at 70 ◦C (88.35 %), using a 1:1 cosolvent ratio. Films incorporated with oil exhibited lower water vapor permeability (WVP) than those with only cross-linked gelatin (1.59 (g m− 1 s − 1 Pa− 1 ) 1011). The film with the most suitable tensile strength (19.07 MPa), elongation (120.91 %), and WVP (1.09 (g m− 1 s − 1 Pa− 1 ) 1011) properties contained garlic oil extracted at the central point (55 ◦C and 1:2). Thermal analysis indicated increased melting temperatures in films with added oil, suggesting low thermal degradation. These results suggest that garlic oil addition can improve the properties of fish gelatin-based films, making them promising for biodegradable packaging.
Article
Full-text available
Information about the adverse effects of lactation transfer of abamectin (ABA) is important for human health, especially in the third-world countries where breastfeeding is the only source of nutrition for infants. So, the present study was undertaken to evaluate the adverse effects of breastfeeding exposure to ABA on oxidative damage and liver and kidney dysfunction in suckling rats. Dams were orally administered ABA at a doses 22.10, 11.05, and 2.21 mg a.i./kg b.wt from postnatal day 1 (PND1) until day 20 (PND20). The signs of toxicity and high mortality were recorded in suckling male (67.5%) and female (55.0%) pups whose mother exposed to the ABA at dose 22.1 mg a.i./kg b.wt. ABA induced significantly decrease in body weights of mothers and their male and female pups and significant increase in relative liver weights. It caused oxidative stress in the liver and kidney of mothers and their pups by increasing the level of malondialdehyde (MDA) and decreased activities of superoxide dismutase (SOD) and glutathione-transferase (GST). ABA altered the level of serum liver and kidney dysfunction biomarkers either in the mothers or their male and female pups in a dose-dependent manner. It caused histopathological alterations in the liver and kidney tissues. It can be decided that ABA was accumulated in mother’s milk, transferred through breast feeding, and induced mortality in their suckling pups. It caused oxidative stress, lipid peroxidation, and biochemical and histopathological alterations in the liver and kidney of mothers and their suckling pups. The results in the present study add some information about the adverse effect of lactation transfer of ABA, which is important for human health in the third-world countries where breastfeeding may be the only source of nutrition for infants in the first and most critical weeks of life.
Article
Full-text available
The acaricidal activity of fourteen essential oils and fourteen of their major monoterpenoids were tested against the house dust mite, Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 hrs under laboratory conditions. In general, it was noticed that the acaricidal effects based on LC50 of either essential oils or monoterpenoids against the dust mites was time dependant. The LC50 values were decreased by increasing of exposure time. Clove, Matrecary, Chenopodium, Rosemary, Eucalyptus and Caraway oils were shown to possess high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of the house dust mite, D. pteronyssinus.
Article
Full-text available
The long-term applications of synthetic insecticides have resulted in residues accumulating in different environmental components. They have adverse effects on non-target organisms, ecosystems and human health. Therefore, bio-insecticides “Green pesticides” have posted as an alternative to synthetic insecticides in agriculture and public health sectors. The study presented here focuses on the prospects of essential oils (EOs) as bio-insecticides for insect pest management. In fact, many EOs have insecticidal, fumigant, antifeedant, attractive and repellent activities against a broad spectrum of insects with some selectivity. The EOs are a complex of chemical compounds with multiple modes of action that enhances their activity due to the synergistic action between constituents. Due to their volatility in nature, EOs are used as a fumigant against agriculture and storage food insects. Consequently, EO-based insecticides are very important for control stored insects because they are active against a variety of insects, fast penetrating and no toxic residues in the treated products. In contrast, some problems (e.g., volatility, solubility and oxidation) of EO-based insecticides were recorded, which plays an important role in the EOs activity, application and persistent. For this reason, new formulations with nanotechnology “Nanoformulation” can resolve these problems and offer numerous advantages. So, encapsulating the EOs has a considerable perspective as commercial insecticide products. Finally, EOs-based insecticides are low toxic, environmental persistence and eco-friendly. Therefore, they are not having worker re-entry and harvest restrictions after treating crops. They are compatible with biological control programs and indigenous natural enemies of pests.
Article
Full-text available
Pterodon emarginatus Vogel is a Brazilian species that belongs to the family Fabaceae, popularly known as sucupira. Its oil has several biological activities, including potent larvicidal property against Aedes aegypti. This insect is the vector of dengue, a tropical disease that has been considered a critical health problem in developing countries, such as Brazil. Most of dengue control methods involve larvicidal agents suspended or diluted in water and making active lipophilic natural products available is therefore considered a technological challenge. In this context, nanoemulsions appear as viable alternatives to solve this major problem. The present study describes the development of a novel nanoemulsion with larvicidal activity against A. aegypti along with the required Hydrophile Lipophile Balance determination of this oil. It was suggested that the mechanism of action might involve reversible inhibition of acetylcholinesterase and our results also suggest that the P. emarginatus nanoemulsion is not toxic for mammals. Thus, it contributes significantly to alternative integrative practices of dengue control, as well as to develop sucupira based nanoproducts for application in aqueous media.