A review on bioactive constituents of essential oils as mosquito repellent

2021 ◽  
Vol 18 ◽  
Author(s):  
Rajat Subhra Dutta ◽  
Supriya Sahu ◽  
Bhaskar Mazumder

Abstract: Currently, the research focus has been on finding new alternatives to synthetic mosquito repellents due to their toxicity. Natural products act as a suitable alternative since plant-based mosquito repellents have been used traditionally due to their low toxicity. Essential oils as mosquito repellent have gained importance due to various functional bioactive constituents. Different formulations of essential oils have been studied from time to time to enhance the stability and protection time. However, the underlying mechanism of repellent activity of the bioactive constituents against specific mosquito species remains unexplored. This review focuses on the various sources of essential oil with their bioactive components and their receptor-based mechanism of action for inducing mosquito repellency against different mosquito species. Furthermore, a comparison of the various formulations of essential oil-based mosquito repellents with synthetic repellents has been discussed.

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3599
Author(s):  
Norashiqin Misni ◽  
Zurainee Mohamed Nor ◽  
Rohani Ahmad ◽  
Nur Raihana Ithnin ◽  
Ngah Zasmy Unyah

Essential oils have been widely used as an active ingredient in mosquito repellent products. However, essential oils are highly unstable and prone to degradation when exposed to the environment during storage. Microencapsulation techniques help to maintain the stability of molecules in essential oils that are sensitive to environmental stress, and therefore improve shelf life. In this study, the physical stability and efficacy of a repellent formulation consisting of encapsulated Citrus grandis essential oil (CGEO) were evaluated under different storage conditions over a 12-month period by comparing the formulation with a non-encapsulated formulation. The formulations were both stored under two different storage conditions, i.e., 25 ± 2 °C/60% ± 5% relative humidity (RH) and 40 ± 2 °C/75% RH ± 5%, for 12 months. Droplet size, zeta potential, and pH value were measured after 1, 6, and 12 months of storage to determine their stability. For the study of efficacy, each formulation was tested against Aedes aegypti under laboratory conditions. We found that the microencapsulated formulation’s physical characteristics showed insignificant changes as compared with the non-encapsulated formulation during storage. The microencapsulated formulation demonstrated better repellent effects, sustaining high protection (>80%) for 4 more hours of exposure after 12 months of storage as compared with the non-encapsulated formulation that demonstrated high protection for only an hour post application. Microencapsulation helped to preserve the stability of the formulation, which resulted in high protection being maintained for over 12 months of storage.


2017 ◽  
Vol 23 (2) ◽  
pp. 192 ◽  
Author(s):  
Guilherme Mariano Manfredini ◽  
Patrícia Duarte de Oliveira Paiva ◽  
Elka Fabiana Aparecida Almeida ◽  
Ângela Maria Pereira Do Nascimento ◽  
Thaís Silva Sales ◽  
...  

The loss of commercial quality during storage and transportation of roses is one of the factors that reflect on production costs, leading producers to preventively apply harmful chemicals, mainly to hamper Botrytis cinerea development and reduce further losses. An alternative to increase flower longevity without contaminating the environment with harmful chemicals is the use of natural products, such as essential oils, which have fungistatic and insecticide properties, as well as low toxicity. The objective of this study was to evaluate the effect of essential oils on the vase life of Rosa cv. Avalanche: 12 treatments were tested, resulting from the combination of 5 types of essential oils plus the control in two cold storage periods (2 to 6 days) at 1 °C, 90-95% RH. The essential oils tested were eucalyptus, cinnamon, lemongrass and peppermint (1%), clove (0.1%), plus a control with distilled water. Application was made by spraying the flower buds. After storage at low temperatures, the flower stems were kept in a room (16 °C, 70% RH) during 10 days for evaluation. Flower stems stored for 2 days in a cold chamber showed better means for darkening, turgor and bent neck, as well as a lower weight loss by the stems. The application of lemongrass essential oil at 1% caused burns on the petals, compromising quality and pot life. The essential oils of peppermint and eucalyptus allowed flower quality maintenance until the 10th day of evaluation. It is possible to conclude that post-harvest spraying with peppermint or eucalyptus essential oil at 1%, combined with cold storage for 2 days, provided greater longevity and quality for cv. Avalanche roses.


2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601 ◽  
Author(s):  
Megil McNeil ◽  
Petrea Facey ◽  
Roy Porter

Several species belonging to the Hyptis (Lamiaceae) genus represent an important source of bioactive constituents, which are reputed for their wide range of antimicrobial, anticancer and insecticidal activities. The volatile oils obtained from various parts of the Hyptis plants were found to be primarily composed of mono- and sesquiterpenes. Significant differences were observed in the percentage compositions of the major components, which allowed for differentiation among the species. Based on the dominant constituents, phylogenetic relationships were found to be common among some species: 1,8-cineole ( H. fruticosa, H. goyazensis, H. martiusii and H. suaveolens); β-caryophyllene ( H. marrubioides, H. pectinata, H. spicigera and H. suaveolens); eugenol ( H. recurvata and H. suaveolens); γ-cadinene ( H. glomerata and H. ovalifolia); p-cymene ( H. mutabilis and H. pectinata); α-pinene ( H. crenata and H. emoryi). The monoterpenes, α-pinene and p-cymene were detected at various concentrations in all the Hyptis oils investigated. This paper reviews the essential oil compositions of eighteen Hyptis plant species studied in various parts of the world covering the publications of 100 years (1909 to 2009) after the first article appeared in the literature.


2013 ◽  
Vol 14 (1&2) ◽  
pp. 21-25
Author(s):  
M. F. Alam

Light green essential oils extracted from the leaves of Eupatorium odoratum (Asterace) from Himalaya region (India) were screened for repellent activity against Anopheles stephensi, Aedes aegypti and Culex quinquifaciatus mosquitoes. The repellent activity was evaluated in door condition. Four concentrations 2.5%, 5%, 7.5% and 10% (v/v) in ethanol were considered in this study. When the test oil was applied at 10% concentration were found most effective and provided more than 2hr of complete protection against all three mosquito species. The complete protection time (Mean ± S.D) were recorded as 160.2 ± 2.77min, 139.4 ± 1.14min and 125.6 ± 3.13min against Anopheles stephensi, Aedes aegypti and Culex quinquifaciatus respectively. There was no bite within 125min and 160min confirm due to action of essential oil and thus 100% protection from the bite of mosquitoes achieved. No adverse effects of the human volunteers were observed during the exposure and through three months after the application.Therefore, the essential oil of Eupatorium odoratum (Asterace) may prove useful in the development of mosquito natural repellents as an effective personal protection measure against mosquito bites.


2020 ◽  
Vol 981 ◽  
pp. 253-257
Author(s):  
Hazrulrizawati Abd Hamid ◽  
Nishantini Silvarajoo ◽  
Nurulhusna Ab. Hamid

The mosquito Aedes aegypti is an epidemic vector of several diseases such as dengue fever and yellow fever. Several pesticides are used to control the mosquito population. Because of their frequent use, some mosquitoes have developed resistance. In the present study, we evaluated the synergistic mosquito-repellent activity of essential oils from Pelargonium radula, Syzgium aromaticum and Citrus aurantifolia against Aedes aegypti by using Y-tube olfactometer. The oils was subsequently analyzed by using GC–MS. These results clearly reveal that the essential oil of C. aurantifolia served as the most potent repellent agent against Aedes aegypti . The results indicate that three constituents; limonene (19.58%) followed by β–pinene (17.12%), geraniol (13.23%) which comprise a large proportion of the C. aurantifolia are likely responsible for the observed repellent activity.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 70-70
Author(s):  
Janghan Choi ◽  
Lucy Wang ◽  
Joshua Gong ◽  
Ludovic Lahaye ◽  
Song Liu ◽  
...  

Abstract Essential oils are defined as plant-derived natural bioactive compounds with positive effects on animal growth and health due to their antimicrobial and antioxidative properties. However, essential oils are very volatile, can evaporate rapidly and be rapidly absorbed in the upper gastrointestinal tract. In addition, due to their labile nature, the stability of essential oils during feed processing is often questionable, leading to variable final concentrations in feeds. Micro-encapsulation has become one of the most popular methods to deliver essential oils into the lower gut. The objective of the present study was double: 1) to validate and demonstrate the slow release of essential oils, such as thymol, micro-encapsulated in combination with organic acids in a matrix of triglycerides, in simulated swine gastric and intestinal fluids and 2) to evaluate the essential oil stability in the microparticles during feed pelleting process. In the in vitro release experiments, the microparticles were incubated in simulated gastric fluids for 2 hours and then the samples were incubated in simulated intestinal fluids for 0, 1, 2, 3, 4, 6, 8, 10, and 24 hours at 39°C. In the pelleting experiment, a wheat-corn basal diet with 2 kg of micro-encapsulated product was formulated and pelleted. The thymol content in the samples was analyzed by gas chromatography with flame-ionization detection. The results showed that 27.65% thymol was released in simulated gastric fluids and the rest of thymol was progressively released in intestinal fluids until completion, which was achieved by 24 hours. The thymol concentration was not significantly different between the mash feeds and pelleted feeds (P > 0.05). In conclusion, the micro-encapsulated organic acid and essential oil product was able to maintain the stability of thymol under a commercial pelleting process and allow a slow and progressive release of its active ingredients as thymol in simulated digestive fluids.


Author(s):  
Zahra Sheikh ◽  
Amir Amani ◽  
Hamid Reza Basseri ◽  
Seyed Hassan Moosa Kazemi ◽  
Mohammad Mehdi Sedaghat ◽  
...  

Background: Mosquito species are highly considering as disease transmission as well as nuisance insects. One of the principal strategy to protect human from the mosquito bites is repellent agents. This study aimed to assess repellency of two organic essential oils, Eucalyptus globulus and Syzygium aromaticum from bites of malaria vector, Anopheles stephensi. Methods: The study was conducted in 2019-2020. The components of essential oils of E. globulus and S. aromaticum was determined using gas chromatography/mass spectrometry. The unfed female mosquitoes aged 2-5 d old were used in all experiments. In vivo Klun and Debboun module bioassays were utilized on human-volunteer skin. The essential oils at serial concentrations were used to find repellent efficacy against Anopheles landings and bites. To find the synergistic effect, four combinations of the essential oils were tested. Results: The main composition of E. globulus essential oil was 1,8-Cineol (78.20%), whereas that of S. aromaticum essential oil was 2-methoxy-3-(2-propenyl) (77.04%). Based on minimum effective dose (≤1% biting), 10% (v/v) of E. globulus showed high landing repellency (77.78%), whereas minimum effective dose of S. aromaticum at concentration of 1% had high landing repellency (88.89%). Among four combinations, the ratio of 1:1 of E. globulus (10%):S. aromaticum (1%) showed the most landing repellency (94.44%). Conclusion: The combinations of two essential oils had the most potential repellency effect against landing of mosquitoes. As essential oils are eco-friendly with less irritation for human skin, E. globulus and S. aromaticum essential oils are recommended as effective and safe mosquito repellents.


2020 ◽  
Vol 5 (2) ◽  
pp. 71-79
Author(s):  
Dwi Setyaningsih ◽  
Fitriana Roselly ◽  
Neli Muna

Essential oil has complex chemical substances with a lot of benefit, one of them is as mosquitoe or insect repellent. This research aims to find out the best essential oil formula for mosquito repellent. Essential oils that used in this research are citronella, lemongrass, cajeput, and lavender oil. Essential oils are characterized by its color, density, refractive index, and solubility in alcohol. The essential oil colors met the SNI which was pale yellow to clear yellow, the density was 0.8125 - 0.9114 g/ml, the refractive index was 1.4568-1.4665 and soluble in alcohol. The essential oil mixture resulted in 7 series of formula, namely series A1-A5, B1-B5, C1-C5, D1-D5, E1-E5, F1-F5, and G1-G5. The organoleptic test performed on all formula showed that the preferred formula was the formula E3, G3, and F3. All preferred formula were carried out repellent tests against mosquitoes to determine the effectiveness of the oil mixture in Virgin Coconut Oil (VCO) carrier. The result showed that E3 was more effective repellent compare to F3 and G3 formulas, because it has protection value more than 90% until fourth-hour.


2021 ◽  
pp. 189-194
Author(s):  
Ledianasari ◽  
Deby Tristiyanti ◽  
Elva Maulydha Tanjung ◽  
Lovelyta Barani

Background: The way to improve the stability of jeringau rhizome essential oils is microencapsulation using β-cyclodextrin. Objective: To determine the efficiency of coating the jeringau rhizome essential oil with β-cyclodextrin and examine its thermostability. Method: The microencapsulation method used was freeze-drying with a ratio of 1:20 and 1:30. Results: The microcapsule efficiency at the ratio of 1:20 and 1:30 was 81.67% and 60.70%, respectively. The thermostability test results showed that the degradation constant of 1:20 microcapsule at 50oC and ambient temperature was 0.0054 and 0.0029, respectively, with a half-life of 128.33 hours and 238.97 hours. Meanwhile, the degradation constant of 1:30 microcapsule was 0.0182 and 0.0080, with a half-life of 38.07 hours and 86.63 hours. Conclusion: The highest efficiency is in the ratio of 1:20 with a percentage of 81.67%. In the thermostability test, the 1:20 microcapsule was better protected and had a longer half-life than the 1:30 microcapsule.


2020 ◽  
Vol 10 (5) ◽  
pp. 631-641
Author(s):  
Shahnaz Soufi ◽  
Majid Aminzare ◽  
Hassan Hassanzad Azar ◽  
Koorosh Kamali

Background: Nowadays, the application of several and natural preservatives in small quantity is a more preferred approach. In this regard, one of the effective methods is the formation of nanoemulsion of essential oils. Objective: The objective of this study was to compare the in vitro antibacterial activities of cinnamaldehyde (CIN) and Zataria multiflora essential oil in conventional (ZEO), nanoemulsion (NZEO) and fortified nanoemulsion (NZEOC) forms against common foodborne pathogens. Methods: Firstly, the Zataria multiflora essential oil was analyzed by GC-MS. The nanoemulsion of Z. multiflora essential oil was then prepared alone and fortified with cinnamaldehyde. Finally, their antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis and Escherichia coli was evaluated. Results: Based on the results, carvacrol (36.62%) was found to be the most important compound of essential oil. In disc diffusion and micro-dilution methods, the addition of CIN to ZEO during nanoemulsion formation (NZEOC) showed more antibacterial activity when compared to the individual addition of NZEO and CIN (NZEO+CIN). However, according to the vapor phase diffusion method, nano-treatments exhibited less inhibitory effects than the other treatments. Conclusion: It can be concluded that the fortification of essential oils with their derived pure compounds during nanoemulsion formation, can be used as a suitable alternative to chemical antibacterial compounds in the food industry.


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