Evaluation of Repellent Activity of an Artemisia absinthium L.-Based Topical Formulation Against Anopheles stephensi and Aedes aegypti.

Protection against mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus using a novel insect repellent, ethyl anthranilate

1133 Development of 5α-reductase-containing cells in the forebrain of neonatal rats

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.

Indian Journal of Natural Products,2022,36,1,2-16.DOI:10.5530/ijnp.2022.1.2Published:February 2023Type:Review ArticleAuthors:Disha Sharma, Vandana Singh, Manoj Kumar Yadav, Umesh Kumar Patil, Vinod Kumar Dixit, and Narayan Prasad Yadav Author(s) affiliations:Disha Sharma1, Vandana Singh1, Manoj Kumar Yadav1, Umesh Kumar Patil2, Vinod Kumar Dixit2, Narayan Prasad Yadav1,* 1Bioprospection and Product Development, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, Uttar Pradesh, INDIA. 2Department of Pharmaceutical Sciences, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar, Madhya Pradesh, INDIA. Abstract:Mosquitoes are majorly responsible for causing vector-borne diseases such as malaria, filariasis, chikungunya, dengue, zika, yellow fever, west nile etc. Aedes, Anopheles, Culex are the main genera among other mosquitoes’ species, that are affecting human beings with such dreadful diseases worldwide. To control the transmission of diseases by mosquitoes generally mosquito nets, ITNs and LLINs, DDT, DEET, IR3535 are being used. Prolong use of these harmful chemicals not only cause development of resistance in mosquitoes but also have shown adverse effects on humans as well as on environment. So, there is a growing urge/ need of finding a suitable mosquito repellent from natural origin, that have potential to prevent such vector-borne diseases with least side- effects on humans as well as on environment. In this review, we have enlisted various Essential oils (EO) that are having mosquito repellent properties and some of them such as Cymbopogon nardus, Eucalyptus maculata, Cymbopogon excavatus, Mentha piperita, Azadirachta indica are already used in various mosquito repellent formulations that are being marketed presently. EO of particular plant can be extracted from respective parts of it such as seeds, roots, rhizomes, stems, leaves, bracts, fruits, bark and inflorescences mainly by hydrodistillation, steam distillation, maceration, absorption and supercritical extraction, as well as a mechanical process at room temperature. Gas chromatography coupled to mass spectrometry (GC-MS) is the identification technique used for identification of EO constituents. In addition, the combinations of potent EOs are also found to be the best effective way to be used as mosquito repellent so that repellent potential enhanced due to synergism as well as negates the harmful effects of individual oils. The efficiency of essential oils as well as its protection time can also be enhanced by using vanillin and formulation techniques like microencapsulation and nanoemulsion. Based on market coverage as well as economical cost, synthetic repellents are frequently marketed than essential oils but these EOs, extracts or natural products have the potential to provide efficient and safer repellents for humans as well as the environment. Keywords:Aedes aegypti, Anopheles stephensi, Dengue, Essential oils combinations, Herbal mosquito repellent, Malaria., Natural productsView:PDF (477.03 KB)

Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito larvicidal, ovicidal, and repellent activities of the reported E. coronaria and Caesalpinia pulcherrima plants.

Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. The aim of the present study, to evaluate the larvicidal, pupicidal, repellent, and adulticidal activities of methanol crude extract of Artemisia nilagirica were assayed for their toxicity against two important vector mosquitoes, viz., Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). The fresh leaves of A. nilagirica were washed thoroughly in tap water and shade dried at room temperature (28 ± 2 °C) for 5-8 days. The air-dried materials were powdered separately using commercial electrical blender. From the plants, 500 g powdered was macerated with 1.5 L organic solvents of methanol sequentially for a period of 72 h each and filtered. The larval and pupal mortality was observed after 24 h of exposure; no mortality was observed in the control group. The first- to fourth-instar larvae and pupae of A. stephensi had values of LC(50) = 272.50, 311.40, 361.51, 442.51, and 477.23 ppm, and the LC(90) = 590.07, 688.81, 789.34, 901.59, and 959.30 ppm; the A. aegypti had values of LC(50) = 300.84, 338.79, 394.69, 470.74, and 542.11 ppm, and the LC(90) = 646.67, 726.07, 805.49, 892.01, and 991.29 ppm, respectively. The results of the repellent activity of plant extract of A. nilagirica plants at five different concentrations of 50, 150, 250, 350, and 450 ppm were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, the plant crude extract gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. The adult mortality was found in methanol extract of A. nilagirica, with the LC(50) and LC(90) values of 205.78 and 459.51 ppm for A. stephensi, and 242.52 and 523.73 ppm for A. aegypti, respectively. This result suggests that the leaf extract have the potential to be used as an ideal eco-friendly approach for the control of vector mosquito as target species.

Characterisation of mosquito repellents using arm-in-cage tests are performed by assessing the 95% effective dose (ED95), half-life and complete protection time (CPT). This study fully characterizes these properties for p-menthane-3,8-diol (PMD), which has not been widely studied, and a long-acting formulation containing a PMD-vanillin composite. A series of arm-in-cage tests against Aedes aegypti (Diptera: Culicidae) mosquitoes were devised using 6 volunteers to estimate CPT or 10 to estimate the ED95 and half-lives for three repellents: 20% N,N-diethyl-3-methylbenzamide (DEET), 30% PMD and a novel 30% PMD-vanillin formulation. Non-linear regression analysis was used to characterize the relationship between applied dose and CPT. PMD and DEET showed a very similar log dose relationship to CPT; however, the PMD-vanillin formulation exhibited a sigmoidal 'S-shaped' relationship. This resulted in a 1.5-fold higher CPT for PMD-vanillin compared with that of 20% DEET when applied at a dose of 1.6mg/cm2, but little difference was observed at lower doses of 0.8-1mg/cm2. The ED95 value for the 30% PMD and PMD-vanillin formulations were 0.25 and 0.24mg/cm2, respectively, these being higher than that for 20% DEET (0.09mg/cm2). The half-lives for 30% PMD and 20% DEET were similar (2.23vs. 2.74h), but longer for the PMD-vanillin formulations (3.8h). A full characterisation for other repellent formulations, particularly those claiming extended longevity, should be conducted in order to identify differences at various applied doses.

The tremendous worldwide efforts to isolate novel mosquito larvicidal bacteria with improved efficacy present significant promise to control vector-borne diseases of public health importance. In the present study, two native bacterial isolates, Bacillus thuringiensis (Bt SV2) and Serratia species (SV6) were evaluated for mosquito larvicidal potential against the early fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus with reference to B. thuringiensis subsp. israelensis (Bti) H 14. The native Gram-positive, spore-forming Bt SV2 isolate showed 100% mortality against early fourth instars of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, in parallel to Bti H14 strain. After 24 h, Bt SV2 showed 98%, 89%, and 80.67%, and Bti H14 showed 92%, 98.33%, and 60% mortality against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, respectively. Serratia SV6 showed highest activity against Culex quinquefasciatus (100%) followed by Anopheles stephensi (95%) and Aedes aegypti (91%) after 48 h of exposure. The Gram-negative Serratia SV6 showed delayed toxicity compared to Bti H14 and Bt SV2 against early fourth instars of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. The relative mortality of all treatments after 12-h exposures showed the varied toxicity with respect to exposure time, bacterial treatment, and mosquito species. Genetic relatedness of the strains was confirmed on the basis of phylogenetic reconstructions based on alignment of 16S rRNA gene sequences which indicated a strong clustering of the strain SV2 with B. thuringiensis and the strain SV6 with Serratia nematodiphila. In conclusion, the native isolate B. thuringiensis SV2 showed significant toxicity while Serratia SV6 showed less and delayed toxicity against several mosquito species compared with BtiH14. They may be used as novel bacterial insecticidal agents in mosquito vector-borne disease control. To our knowledge, this is the first report on mosquito larvicidal potential of Serratia species.

Dengue is one of the most dangerous vector-borne diseases transmitted by Aedes mosquitoes. The use of mosquito repellents to protect human hosts and insecticides to reduce the mosquito population is a crucial strategy to prevent the disease. Here, we reported larvicidal and repellent activities of Mentha arvensis L. essential oil against Aedes aegypti, the main vector of the disease. The essential oil was extracted by hydro-distillation from the aromatic plant grown in Vietnam. The yield was 0.67% based on the weight of fresh leaves. The essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The main components were menthol (66.04%), menthyl acetate (22.19%), menthone (2.51%), and limonene (2.04%). Toxicity test on Aedes aegypti larvae showed that the median lethal concentrations, LC50 and LC90 were 78.1 ppm (part per million) and 125.7 ppm, respectively. Besides, the essential oil showed excellent repellency on Aedes aegypti mosquitoes. At 25%, 50%, and 100% concentration, the respective complete protection times (CPTs) were 45 min, 90 min, and 165 min. When adding 5% vanillin to the essential oil (25%), the complete protection time of the essential oil increased up to 120 min. In conclusion, the EO from Mentha arvensis L. has been shown to be a promising natural larvicide and repellent against Aedes aegypti mosquitoes.

Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticides, in the present study, the repellent activity of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Erythrina indica and root of Asparagus racemosus were assayed for their repellency against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The crude extract was applied on a membrane used for membrane feeding of unfed mosquitoes in a 1-ft cage. About 50 unfed 3-4-day-old laboratory-reared pathogen-free strains of A. stephensi, A. aegypti, and C. quinquefasciatus were introduced in a 1-ft cage fitted with a membrane with blood for feeding with temperature maintained at 37 °C through circulating water bath maintained at 40-45 °C. Three concentrations (1.0, 2.0, and 5.0 mg/cm(2)) of the crude extracts were evaluated. Repellents in E. indica afforded longer protection time against A. stephensi, A. aegypti, and C. quinquefasciatus than those in A. racemosus at 5.0 mg/cm(2) concentration, and the mean complete protection time ranged from 120 to 210 min with the different extracts tested. In this observation, these two plant crude extracts gave protection against mosquito bites; also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf extract of E. indica and root extract of A. racemosus have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This is the first report on the mosquito repellent activity of the reported A. racemosus and E. indica plants.

Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus

Background: Dengue Hemorrhagic Fever (DHF) is a disease caused by a virus that is transmitted through the bite of the Aedes aegypti mosquito which has been infected by the dengue virus from DHF patients. Jackfruit leaf extract containing saponins, flavonoids, alkaloids, terpenoids, steroids and tannins can kill the Aedes aegypti mosquito. Based on the background of the researchers interested in testing the formulation of the Jackfruit Leaf Extract Lotion (Artocarpus heterophyllus) as a repellent against the Aedes aegypti mosquito. Purpose: To determine the effect of repellant extract of jackfruit leaf (Artocarpus heterophyllus) against Aedes aegypti mosquitoes. Method: Extraction of percolation with various tests, including the test of alkaloids, flavonoids, saponins, tannins, steroids, triterpenoid, evaluation of mosquito repellent lotions. Results: The concentration of jackfruit leaf extract (Artocarpus heterophyllus) in lotion preparations was the most effective as a mosquito repellant Aedes aegypti, namely at a concentration of 9% with almost the same effectiveness as the positive control, namely 86% at 30 seconds and per 6 hours got an average of 79 .5% with a statistical test value of p < 0.05. Conclusion: Jackfruit leaf extract in lotion preparation has effectiveness in repelling mosquitoes. Keywords: Dengue Fever; Jackfruit leaves (Artocarpus heterophyllus); Aedes aegypti mosquito Pendahuluan: Demam Berdarah Dengue (DBD) merupakan penyakit yang disebabkan oleh virus yang ditularkan melalui gigitan nyamuk Aedes aegypti yang sebelumnya telah terinfeksi oleh virus dengue dari penderita DBD. Ekstrak daun nangka yang mengandung saponin, flavonoid, alkaloid, terpenoid, steroid dan tanin dapat membunuh nyamuk Aedes aegypti. Berdasarkan latar belakang peneliti tertarik untuk melakukan Uji Formulasi Sediaan Lotion Ekstrak Daun Nangka (Artocarpus heterophyllus) sebagai Repelan Terhadap Nyamuk Aedes aegypti. Tujuan: Untuk mengetahui efek Repelan ekstrak daun nangka (Artocarpus heterophyllus) terhadap nyamuk Aedes aegypti. Metode: Ekstraksi perkolasi dengan berbagai uji diantaranya uji alkaloid, flavonoid, saponin, tanin, steroid, triterpenoid, evaluasi lotion anti nyamuk. Hasil: Konsentrasi ekstrak daun nangka (Artocarpus heterophyllus) dalam sediaan lotion yang paling efektif sebagai reppelan nyamuk Aedes aegypti yaitu pada konsentrasi 9% dengan daya efektivitas yang hampir sama dengan kontrol positif yaitu 86% pada 30 detik dan per 6 jam diperoleh rata-rata 79,5% dengan nilai uji statistik p < 0,05. Simpulan: Ekstrak daun nangka dalam sediaan lotion memiliki efektivitas dalam menolak nyamuk.Kata kunci: Demam Berdarah; Daun Nangka (Artocarpus heterophyllus); Nyamuk Aedes aegypti. Kata Kunci: Demam Berdarah; Daun nangka (Artocarpus heterophyllus); Nyamuk Aedes aegypti

Mosquitoes alone transmit diseases to around 700 million individuals annually, killing approximately 0.7 million people every year worldwide. Considering the potential health risks linked with synthetic repellents, it has become vital to identify eco-friendly, natural repellents for mosquito control as well as to understand the underlying mechanism for mosquito repellent activity. To address this, objectives were set to extract essential oils from Citrus macroptera peel and Homalomena aromatica (Spreng.) Schott. rhizomes, evaluate their mosquito repellent activity against Aedes aegypti, and further explore their mosquito odorant receptor inhibition potential. The oils were extracted using Clevenger's apparatus, and properties like specific gravity, refractive index, and boiling point were evaluated and characterised using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC-MS). Aedes aegypti mosquito eggs collected from the Indian Council of Medical Research (ICMR), Dibrugarh, were reared in the Department of Pharmaceutical Sciences, Research Laboratory, to obtain adult Aedes aegypti mosquitoes for the mosquito repellent activity evaluation of the essential oils using the Human Bait technique'. Molecular docking studies were performed for the oil components against mosquito odorant binding proteins. Further, toxicity studies of these two oils were evaluated against human dermal fibroblast adult (HDFa) cells. The results revealed the presence of limonene (86.76%) and linalool (52.35%), respectively, in Citrus macroptera and Homalomena aromatica oils. It was found that the combination of the oils in a ratio of 1:1 showed mosquito repellent activity for up to 6.33 ± 0.23 h. Molecular docking studies showed the presence of major oil components having mosquito odorant receptor blocking potential comparable to N, N-diethyl-meta-toluamide (DEET), indicating a rationale for extended mosquito repellent action. Further, both of these oils were found to be non-cytotoxic against HDFa cells after 24 h. The encouraging mosquito repellent activity of these two oils as compared to synthetic mosquito repellent DEET might pave the way for the development of novel herbal mosquito repellent formulations containing these essential oils.

We determined the degree of personal protection provided by citronella, linalool, and geraniol in the form of commercially available candles or diffusers, both indoors and outdoors. Under the uniform conditions of the experiments, all substances repelled significantly more mosquitoes than the unprotected control. Furthermore, the repellents tested were more active when in the form of a continuous release diffuser than in candle form. All candles were 88 g containing 5% of the active ingredient and all diffusers contained 20 g of 100% active ingredient. Indoors, the repellency rate of citronella candles was only 14% while the repellency rate of citronella diffusers was 68%. The repellency of geraniol candles was 50% while the diffusers provided a repellency rate of 97%. No linalool candles were available for study but linalool diffusers repelled mosquitoes by 93%. Outdoors, citronella diffusers placed 6 m from mosquito traps repelled female mosquitoes by 22%, linalool repelled females by 58%, and geraniol repelled females by 75%. Trap catches were significantly reduced again when diffusers were placed 3 m from the traps. We concluded that geraniol had significantly more repellent activity than citronella or linalool in both indoor and outdoor settings.

Many of the vector-borne diseases that harm humans and animals are transmitted by mosquitos. Malaria, filariasis, Japanese encephalitis, dengue fever, dengue haemorrhagic fever and yellow fever are all transmitted by mosquitos. Aedes aegypti and Anopheles stephensi are two mosquito species that are vectors. Yellow fever, dengue fever and chikungunya are all spread by Aedes aegypti, which is found across the tropical and subtropical zones. In India and other west Asian nations, A. stephensi is the predominant malaria vector. In both the Plectranthusamboinicus and Sphagneticolacalendulacea plant extracts, GC-MS analysis revealed 27 compounds. The mosquitocidal effectiveness of Plectranthusamboinicus and Sphagneticolacalendulacea ethyl acetate extracts against Aedes aegypti and Anopheles stephensi was investigated. Third and fourth instar larvae of Aedes aegypti and Aedes stephensi were killed after 24 and 48 hours of treatment in control by 50, 100, 120, 140, 150, 160, 180, 200, 250, 300 and 350 ppm concentrations respectively. The plant extracts were screened to identify the phytochemical bioactive compounds. A. aegypti was found to be most susceptible than the other species. LC50 and LC90 values of ethyl acetate extract were calculated against Aedes aegypti and Anopheles stephensi. The extracts of the plant showed potent larvicidal efficacy and can be considered for further investigation.