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Kirar M, Singh SP, Singh H, Sehrawat N. Efficacy of maturase K and rpL20 protein extracted from C. procera leaves on Anophelesstephensi. Toxicon 2024; 243:107714. [PMID: 38626820 DOI: 10.1016/j.toxicon.2024.107714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/26/2024]
Abstract
The present work is carried out to protein isolation, purification, and characterization from leaves, stem, and seed of C. procera and to evaluate the larvicidal potential on Anopheles stephensi. The whole protein was isolated using protein extraction buffer and precipitated by ammonium sulphate and larvicidal active protein was purified by the column chromatography. The homogeneity of larvicidal protein was confirmed by the SDS-PAGE. The identification of protein was done by the HPLC and LC-MS/ESI-MS. The crude protein from leaves showed 100% mortality of 3rd instar larvae of An. stephensi at the concentration of 5.5 mg/ml after 24 h of exposure. The crude protein from stem showed 25% mortality and no mortality observed was observed in seed protein. The leaves crude protein was further purified by ion exchange chromatography and eluted fractions were tested for larvicidal potential. The purified single protein fractions L2 and L3 from C. procera leaves showed 100% mortality at concentration of 0.06 mg/ml. The homogeneity of purified protein was confirmed by SDS-PAGE and two bands of 26 kDa and 15 kDa protein were observed. The peptide sequence "R.SQMLENSFLIENVMKR.L" was identified in the trypsin digested homogenous protein fraction L2 and "R.DRGSQKR.N" peptide sequence in L3 fraction by LC-MS/ESI-MS. The CprL2 peptide showed the sequence similarity with the protein maturase K and CprL3 peptide showed the sequence similarity with ribosomal protein L20 of C. procera. The conserved functional domain was also identified in both the CprL2 and CprL3 peptide. The identified proteins showed strong larvicidal efficacy at very low concentration. The identified proteins are novel and natural larvicidal agents against An. stephensi and hence can be used to control the malaria.
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Affiliation(s)
- Manisha Kirar
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - S P Singh
- National Institute for Malaria Research, New Delhi, India
| | - Hitesh Singh
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Neelam Sehrawat
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India.
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Rants'o TA, Koekemoer LL, van Zyl RL. Bioactivity of select essential oil constituents against life stages of Anopheles arabiensis (Diptera: Culicidae). Exp Parasitol 2023:108569. [PMID: 37330107 DOI: 10.1016/j.exppara.2023.108569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 06/14/2023] [Accepted: 06/14/2023] [Indexed: 06/19/2023]
Abstract
Malaria is transmitted by infected female Anopheles mosquitoes, and An. arabiensis is a main malaria vector in arid African countries. Like other anophelines, its life cycle comprises of three aquatic stages; egg, larva, and pupa, followed by a free flying adult stage. Current vector control interventions using synthetic insecticides target these stages using adulticides or less commonly, larvicides. With escalating insecticide resistance against almost all conventional insecticides, identification of agents that simultaneously act at multiple stages of Anopheles life cycle presents a cost-effective opportunity. A further cost-effective approach would be the discovery of such insecticides from natural origin. Interestingly, essential oils present as potential sources of cost-effective and eco-friendly bioinsecticides. This study aimed to identify essential oil constituents (EOCs) with potential toxic effects against multiple stages of An. arabiensis life cycle. Five EOCs were assessed for inhibition of Anopheles egg hatching and ability to kill larvae, pupae and adult mosquitoes of An. arabiensis species. One of these EOCs, namely methyleugenol, exhibited potent Anopheles egg hatchability inhibition with an IC50 value of 0.51 ± 0.03 μM compared to propoxur (IC50: 5.13 ± 0.62 μM). Structure-activity relationship study revealed that methyleugenol and propoxur share a 1,2-dimethoxybenze moiety that may be responsible for the observed egg-hatchability inhibition. On the other hand, all five EOCs exhibited potent larvicidal activity with LC50 values less than 5 μM, with four of them; cis-nerolidol, trans-nerolidol, (-)-α-bisabolol, and farnesol, also possessing potent pupicidal effects (LC50 < 5 μM). Finally, all EOCs showed only moderate lethality against adult mosquitoes. This study reports for the first time, methyleugenol, (-)-α-bisabolol and farnesol as potent bioinsecticides against early life stages of An. arabiensis. This synchronized activity against Anopheles aquatic stages shows a prospect to integrate EOCs into existing adulticide-based vector control interventions.
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Affiliation(s)
- Thankhoe A Rants'o
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; WITS Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lizette L Koekemoer
- WITS Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Robyn L van Zyl
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; WITS Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Sakka MK, Ioannou CS, Papadopoulos NT, Athanassiou CG. Residual efficacy of selected larvicides against Culex pipiens pipiens (Diptera: Culicidae) under laboratory and semi-field conditions. Environ Sci Pollut Res Int 2023. [PMID: 36626059 DOI: 10.1007/s11356-022-24654-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/05/2022] [Indexed: 01/11/2023]
Abstract
Mosquitoes are a threat worldwide since they are vectors of important pathogens and parasites such as malaria, dengue, yellow fever, and West Nile. The residual toxicity of several commercial mosquito larvicides was evaluated for the control of Culex pipiens pipiens under controlled laboratory and semi-field conditions during late spring and summer of 2013. The evaluation included six different active ingredient formulations, i.e., diflubenzuron Du-Dim), Bacillus thuringiensis var. israelensis (Bti) (Vectobac), spinosad (Mozkill), S-methoprene (Biopren), temephos (Abate), and polydimethylsiloxane (PDMS) (Aquatain), that are currently registered of and had been registered in the past for mosquito control. Under controlled laboratory conditions, the residual activity ranged from 1 week (S-methoprene) up to 2 months (spinosad, PDMS). Exposure of larvicides under semi-field conditions resulted in noticeable differences regarding their efficacy as compared to the laboratory bioassays. Exposure of S-methoprene, Bti, and spinosad, for up to 3 days, resulted in similar adult emergence to the controls. On the other hand, the residual efficacy of diflubenzuron, temephos, and PDMS ranged from 14 to 28 days, depending on the season of exposure. Longevity and fecundity of adults that had emerged from surviving larvae, in most of the cases tested, did not differ significantly from that of the controls. The results of the present study demonstrate the necessity of both field and laboratory studies to draw safe conclusions regarding the efficacy of larvicides against mosquitoes and the selection of the proper formulation for each application scenario. In addition, defining the seasonal variation in the residual toxicity of the tested formulations could be useful for improving mosquitos' management programs.
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Giatropoulos A, Karamaouna F, Ampatzi A, Papachristos D, Michaelakis A. Sublethal effects of oregano essential oil and its major compound carvacrol on biological parameters of Aedes albopictus (Diptera: Culicidae). Exp Parasitol 2022; 242:108392. [PMID: 36191614 DOI: 10.1016/j.exppara.2022.108392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/18/2022]
Abstract
Mosquito management programs rely basically on the use of conventional synthetic larvicides. However, frequent applications and misuse of some synthetic insecticides have led to problems related to mosquito resistance development, harmful effects on human health and unacceptable environmental effects on non-target organisms. Recently, a growing number of phytochemicals has been tested as more eco-friendly larvicides against various mosquito species, exerting high efficacy with multiple modes of action. In the laboratory, we investigated for the first time the sublethal effects of oregano oil and its major compound carvacrol, against Aedes albopictus (Asian tiger mosquito), a mosquito of great medical importance. We determined the effects of short term (24h) exposure of 3rd- 4th larvae to LC50 concentrations on survival and development of survived larvae until adulthood, as well as on fecundity, fertility, longevity and wing length of emerged adults. Only half of 24h survived larvae from oregano oil and carvacrol treatment finally reached adulthood. Abnormal shapes of dead larvae and pupae, and failed adult emergence were also observed, indicating a potential growth inhibitory activity of the tested materials. No particular effects from exposure to larvicidal LC50 concentrations were recorded on life cycle parameters of successfully emerged adults. These findings suggest the tested oregano oil and carvacrol as sufficiently effective larvicides against Ae. albopictus at lower than the acutely toxic concentrations, promoting a more eco-friendly and less costly profile for these biopesticides.
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Affiliation(s)
- Athanasios Giatropoulos
- Laboratory of Efficacy Control of Pesticides, Benaki Phytopathological Institute, 14561, Kifissia, Greece.
| | - Filitsa Karamaouna
- Laboratory of Efficacy Control of Pesticides, Benaki Phytopathological Institute, 14561, Kifissia, Greece
| | - Argyro Ampatzi
- Laboratory of Efficacy Control of Pesticides, Benaki Phytopathological Institute, 14561, Kifissia, Greece
| | - Dimitrios Papachristos
- Laboratory of Agricultural Entomology, Benaki Phytopathological Institute, 14561, Kifissia, Greece
| | - Antonios Michaelakis
- Laboratory of Insects and Parasites of Medical Importance, Benaki Phytopathological Institute, 14561, Kifissia, Greece
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Soni N, Dhiman RC. Larvicidal and antibacterial activity of aqueous leaf extract of Peepal ( Ficus religiosa) synthesized nanoparticles. Parasite Epidemiol Control 2020; 11:e00166. [PMID: 32885057 PMCID: PMC7452144 DOI: 10.1016/j.parepi.2020.e00166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/22/2020] [Accepted: 07/10/2020] [Indexed: 11/09/2022] Open
Abstract
In this study, the zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) were synthesized using the aqueous leaf extract of Ficus religiosa (Peepal tree). The synthesized nanoparticles were tested as larvicides against the larvae of Anopheles stephensi. Further, the synthesized nanoparticles were tested as antibacterial agents against the Escherichia coli (gram negative) and Staphylococcus aureus (gram positive) bacteria. The synthesized nanoparticles were characterized with UV-visible spectroscopy, X-rays powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The larvicidal mortality was observed after 24 h and 48 h by probit analysis. The antibacterial activity was evaluated using the well diffusion method. The synthesized nanoparticles were irregular shape and varied size. The larvae of An. stephensi were found highly susceptible against the ZnO NPs than the TiO2 NPs and aqueous leaves extract. The highest mortality was observed in synthesized ZnO NPs against first to third instars of (LC50 50, 75, and 5 ppm) and 100% mortality in fourth instars of An. stephensi. The higher zone of inhibition was occurred against the E. coli. This report of present investigation revealed that the rapid biological synthesis of ZnO NPs and TiO2 NPs using aqueous leaf extract of F. religiosa would be effective potential larvicides for mosquito control as well as antimicrobial agents with eco-friendly approach.
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Affiliation(s)
- Namita Soni
- Environmental Epidemiology Division, ICMR-National Institute of Malaria Research, New Delhi, India 110077
| | - Ramesh C. Dhiman
- Environmental Epidemiology Division, ICMR-National Institute of Malaria Research, New Delhi, India 110077
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Govindasamy B, Pecoraro L, Velramar B, Tamilselvan S, Pudukadu Munusamy A, Chinnasamy R, Pachiappan P. Evaluation of Salmonella bongori derived biosurfactants and its extracellular protein separation by SDS-PAGE using petridishes: A simply modified approach. Int J Biol Macromol 2019; 140:156-67. [PMID: 31398404 DOI: 10.1016/j.ijbiomac.2019.08.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 11/23/2022]
Abstract
Presently, through the preliminary screening assays, the Salmonella bongori BH11 was found to be an effective biosurfactants (BSFs) producer. The secreted BSFs were extracted using methanol: chloroform and characterized through FTIR, TLC, HPLC and GCMS analyses. Further, the extracellular protein was extracted (TCA/acetone method), estimated (Lowry's method) and separated (standard and modified SDS-PAGE). Through the obtained characteristic FTIR peaks (1107.09cm-1), its content was presumed to be glycolipids and as rhamnose/rhamnolipids through the TLC-Rf value. GCMS revealed 6 compounds, in which Toluene (32%) and 5-(2-Thienyl) pentanoic acid (23%) are the major ones. The crude BSFs exhibited preponderant antibacterial effects on Staphylococcus aureus and Serratia marcescens. Also, it inhibited the biofilm formation of S. aureus, Pseudomonas aeruginosa, P. fluorescens and S. marcescens. Considerably, 76% mortality of IV instar larvae of Culex quinquefasciatus was recorded from BSFs, when compared to SDS. The presently followed protein separation technique using two petridishes might attract the attention of the researchers, as it would emerge as a standard procedure in future. This is the first report on the screening of BSFs from Salmonella bongori that showed antagonistic property, larvicidal potentials and the presently followed modified SDS-PAGE protein separation technique is a simple, reliable and cost effective one.
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Mavridis K, Fotakis EA, Kioulos I, Mpellou S, Konstantas S, Varela E, Gewehr S, Diamantopoulos V, Vontas J. Detection of West Nile Virus - Lineage 2 in Culex pipiens mosquitoes, associated with disease outbreak in Greece, 2017. Acta Trop 2018; 182:64-68. [PMID: 29474832 DOI: 10.1016/j.actatropica.2018.02.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/14/2018] [Accepted: 02/17/2018] [Indexed: 11/26/2022]
Abstract
During July-October 2017 a WNV outbreak took place in the Peloponnese, Southern Greece with five confirmed deaths. During routine monitoring survey in the Peloponnese, supported by the local Prefecture, we have confirmed the presence of all three Culex pipiens biotypes in the region, with a high percentage of Culex pipiens/molestus hybrids (37.0%) which are considered a highly competent vector of WNV. Kdr mutations related to pyrethroid resistance were found at relatively low levels (14.3% homozygosity) while no mosquitoes harboring the recently identified chitin synthase diflubenzuron-resistance mutations were detected in the region. As an immediate action, following the disease outbreak (within days), we collected a large number of mosquitoes using CO2 CDC traps from the villages in the Argolis area of the Peloponnese, where high incidence of WNV human infections were reported. WNV lineage 2 was detected in 3 out of 47 Cx. pipiens mosquito pools (detection rate = 6.38%). The virus was not detected in any other mosquito species, such as Aedes albopictus, sampled from the region at the time of the disease outbreak. Our results show that detection of WNV lineage 2 in Cx. pipiens pools is spatially and chronologically associated with human clinical cases, thus implicating Cx. pipiens mosquitoes as the most likely WNV vector. The absence of diflubenzuron resistance mutations and the low frequency of pyrethroid (kdr) resistance mutations indicates the suitability of these insecticides for Cx. pipiens control, in the format of larvicides and/or residual spraying applications respectively, which was indeed the main (evidence based) response, following the disease outbreak.
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Ishwarya R, Vaseeharan B, Subbaiah S, Nazar AK, Govindarajan M, Alharbi NS, Kadaikunnan S, Khaled JM, Al-Anbr MN. Sargassum wightii-synthesized ZnO nanoparticles - from antibacterial and insecticidal activity to immunostimulatory effects on the green tiger shrimp Penaeus semisulcatus. J Photochem Photobiol B 2018; 183:318-330. [PMID: 29754050 DOI: 10.1016/j.jphotobiol.2018.04.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 04/19/2018] [Accepted: 04/30/2018] [Indexed: 11/17/2022]
Abstract
The green synthesis of metal nanoparticles using phytochemical from marine seaweeds is a fast-growing research field in nanotechnology. Here, the biosynthesis of zinc oxide nanoparticles was achieved using the hot water extract of Sargassum wightii. The hot water extract prepared from S. wightii (H Sw) and ZnO NPs were studied by UV-visible and FTIR spectroscopy, SEM and XRD. Then, both products were evaluated for antibiofilm activity towards aquatic pathogens. The nanoparticles' immunostimulating potential on green tiger prawns, Penaeus semisulcatus was studied through immersion and dietary administration. Shrimp immune parameters (i.e., total hemocytes count (THC), respiratory bursts (RBs), phenoloxidase (PO) and superoxide dismutase (SOD) activity) were significantly affected by exposure or ingestion of ZnO nanoparticles. In addition, the hot water extract and ZnO nanoparticles had high antibiofilm activity against Gram-positive (B. subtilis, S. aureus) and Gram-negative (S. sonnei, P. aeruginosa) microbial pathogens. It was accomplished that the ZnO nanoparticles can be used as the bacteriostatic and immunostimulant agents through immersion and dietary administration enhancing immunity of green tiger shrimp. Furthermore, the toxicity effects of ZnO nanoparticles were 100% at 24 h on Aedes aegypti 3 rd instar larvae at the concentration of 100 μg/mL and the greatest efficacy was accomplished by H Sw ZnO NPs against the Ae. aegypti after 24 h (LC50 49.22; LC90 86.96 mg/mL), if compared to the seaweed extract alone. Morphological and histological damages triggered by nanoexposure were investigated.
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Affiliation(s)
- Ramachandran Ishwarya
- Nanobiosciences and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Science Block, 6th Floor, Burma Colony, Karaikudi 630004, Tamil Nadu, India
| | - Baskaralingam Vaseeharan
- Nanobiosciences and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Science Block, 6th Floor, Burma Colony, Karaikudi 630004, Tamil Nadu, India.
| | - Suganya Subbaiah
- Nanobiosciences and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Science Block, 6th Floor, Burma Colony, Karaikudi 630004, Tamil Nadu, India
| | - Abdul Khudus Nazar
- Mandapam Regional Centre, Central Marine Fisheries Research Institute, Mandapam, Tamil Nadu, India
| | - Marimuthu Govindarajan
- Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India; Department of Zoology, Government College for Women, Kumbakonam 612 001, Tamil Nadu, India
| | - Naiyf S Alharbi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Shine Kadaikunnan
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Jamal M Khaled
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Mohammed N Al-Anbr
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
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Benelli G, Rajeswary M, Govindarajan M. Towards green oviposition deterrents? Effectiveness of Syzygium lanceolatum (Myrtaceae) essential oil against six mosquito vectors and impact on four aquatic biological control agents. Environ Sci Pollut Res Int 2018; 25:10218-10227. [PMID: 27921244 DOI: 10.1007/s11356-016-8146-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
Essential oils (EOs) from plants may be alternative sources of molecules toxic against mosquito vectors of public health relevance. Most of researches in this field focused on EOs as larvicides or ovicides, while limited efforts focused on the exploitation of EOs as oviposition deterrents. In the present study, the larvicidal and oviposition deterrent activity of Syzygium lanceolatum leaf EO was evaluated against six mosquito species, Anopheles stephensi, An. subpictus, Aedes aegypti, Ae. albopictus, Culex quinquefasciatus, and Cx. tritaeniorhynchus. The chemical composition of the S. lanceolatum EO was analyzed by GC-MS analysis, showing the presence of phenyl propanal, β-caryophyllene, α-humulene, and caryophyllene oxide as major constituents. S. lanceolatum EO showed high acute toxicity on An. stephensi (LC50 = 51.20 μg/ml), Ae. aegypti (LC50 = 55.11 μg/ml), Cx. quinquefasciatus (LC50 = 60.01 μg/ml), An. subpictus (LC50 = 61.34 μg/ml), Ae. albopictus (LC50 = 66.71 μg/ml), and Cx. tritaeniorhynchus (LC50 = 72.24 μg/ml) larvae. Furthermore, the EO was effective as oviposition deterrent against the six tested mosquito species, with OAI on An. stephensi, An. subpictus, Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus, and Cx. tritaeniorhynchus reaching -0.83, -0.81, -0.84, -0.83, -0.84, and -0.86, respectively. The toxicity of S. lanceolatum EO against several biological control agents of mosquitoes, including water bugs (Anisops bouvieri and Diplonychus indicus) and fishes (Gambusia affinis and Poecilia reticulata), was extremely low, with LC50 ranging between 4148 and 15,762 μg/ml. Overall, our results pointed out the promising potential of the S. lanceolatum leaf EO as a source of environmental-friendly oviposition deterrents and larvicides effective against a wide number of mosquito species of importance for parasitology.
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Affiliation(s)
- Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124, Pisa, Italy.
| | - Mohan Rajeswary
- Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar, Tamil Nadu, 608 002, India
| | - Marimuthu Govindarajan
- Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar, Tamil Nadu, 608 002, India.
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Thanigaivel A, Vasantha-Srinivasan P, Edwin ES, Ponsankar A, Selin-Rani S, Chellappandian M, Kalaivani K, Senthil-Nathan S, Benelli G. Development of an eco-friendly mosquitocidal agent from Alangium salvifolium against the dengue vector Aedes aegypti and its biosafety on the aquatic predator. Environ Sci Pollut Res Int 2018; 25:10340-10352. [PMID: 28580548 DOI: 10.1007/s11356-017-9102-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Plant extracts with their enriched chemical constituents have established potential alternative mosquito control agents. In this research, we developed an eco-friendly mosquitocidal agent from Alangium salvifolium leaves against the dengue and Zika virus vector Aedes aegypti and we investigated its biosafety on the mosquito aquatic predator Toxorhynchites splendens. Results showed that the methanolic extract of A. salvifolium leaves was composed by eight main compounds, with major peak area for hexadecenoic acid (21.74%). LC50 and LC90 values calculated on Ae. aegypti fourth instar larvae were 104.80 and 269.15 ppm respectively. The methanolic extract tested at 100 ppm decreased the α-β carboxylesterase and SOD ratio significantly and upregulated the GST and CYP450 level. The A. salvifolium methanolic extract displayed significant repellent and adulticidal activity at 100 and 400 ppm respectively. The treatment with 100 ppm of the methanolic extract led to 210 min of protection from Ae. aegypti bites. Four hundred parts per million of the extract showed 98% adult mortality within 30 min from the treatment. Lastly, biosafety assays on the mosquito aquatic predator Tx. splendens showed that the toxicity of the A. salvifolium extract was significantly lower if compared to the cypermethrin-based treatments. The methanolic extract of A. salvifolium showed a maximum of 47.3% mortality rate at the concentration of 1000 ppm, while 0.7 ppm of cypermethrin achieved 91.3% mortality rate on Tx. splendens. Overall, our study enhances basic knowledge on how to improve natural larvicidal agents against dengue and Zika virus mosquito vector with harmless responses on non-target aquatic predators.
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Affiliation(s)
- Annamalai Thanigaivel
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Prabhakaran Vasantha-Srinivasan
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Edward-Sam Edwin
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Athirstam Ponsankar
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Selvaraj Selin-Rani
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Muthiah Chellappandian
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India
| | - Kandaswamy Kalaivani
- Post Graduate and Research Centre, Department of Zoology, Sri Parasakthi College for Women, Courtrallam, Tirunelveli, Tamil Nadu, 627 802, India
| | - Sengottayan Senthil-Nathan
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627 412, India.
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, via del 23 Borghetto 80, 56124, Pisa, Italy
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Thomas A, Mazigo HD, Manjurano A, Morona D, Kweka EJ. Evaluation of active ingredients and larvicidal activity of clove and cinnamon essential oils against Anopheles gambiae (sensu lato). Parasit Vectors 2017; 10:411. [PMID: 28874207 PMCID: PMC5585972 DOI: 10.1186/s13071-017-2355-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/29/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mosquitoes are well-known vectors of many diseases including malaria and lymphatic filariasis. Uses of synthetic insecticides are associated with high toxicity, resistance, environmental pollution and limited alternative, effective synthetic insecticides. This study was undertaken to evaluate the larvicidal efficacy of clove and cinnamon essential oils against laboratory Anopheles gambiae (sensu stricto) and wild An. arabiensis larvae. METHODS The standard WHO guideline for larvicides evaluation was used, and the GC-MS machine was used for active compounds percentage composition analysis and structures identification. Probit regression analysis was used for LC50 and LC95 calculations while a t-test was used to test for significant differences between laboratory-reared and wild larvae populations in each concentration of plant extract. RESULTS Mortality effect of clove and cinnamon essential oils against wild and laboratory-reared larvae had variations indicated by their LC50 and LC95 values. The mortality at different concentrations of cinnamon and clove post-exposure for wild and laboratory-reared larvae were dosage-dependent and were higher for cinnamon than for clove essential oils. The mortality effect following exposure to a blend of the two essential oils was higher for blends containing a greater proportion of cinnamon oil. In the chemical analysis of the active ingredients of cinnamon essential oil, the main chemical content was Eugenol, and the rarest was β-Linalool while for clove essential oil, the main chemical content was Eugenol and the rarest was Bicyclo. CONCLUSION The essential oils showed a larvicidal effect which was concentration-dependent for both laboratory and wild collected larvae. The active ingredient compositions triggered different responses in mortality. Further research in small-scale should be conducted with concentrated extracted compounds.
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Affiliation(s)
- Adelina Thomas
- School of Pharmacy, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania
| | - Humphrey D Mazigo
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania
| | - Alphaxard Manjurano
- National Institute for Medical Research, Mwanza Research Centre, Mwanza, Tanzania
| | - Domenica Morona
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania
| | - Eliningaya J Kweka
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania. .,Division of Livestock and Human Diseases Vector Control, Mosquito Section, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania.
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Alkenani NA. Influence of the mixtures composed of slow-release insecticide formulations against Aedes aegypti mosquito larvae reared in pond water. Saudi J Biol Sci 2017; 24:1181-1185. [PMID: 28855810 PMCID: PMC5562468 DOI: 10.1016/j.sjbs.2017.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 11/26/2022] Open
Abstract
Vector borne diseases remain the major source of illness and death worldwide. Aedes aegypti is the primary carrier of dengue and dengue haemorrhagic fever in many developing countries in the tropical world. Because A. aegypti populations are becoming more and more resistant to conventional and non conventional insecticides, alternative strategies have to be rapidly implemented in the future for dengue vector control. The present study aimed to evaluate the larvicidal efficacy of slow-release formulations (SRFs) of bacterial insecticide Bactimos briquets blended with tow insect growth regulators (IGRs), Altosid XR - briquets and Dudim DT tablet respectively, against mosquito larvae of A. aegypti the primary vector of dengue fever in Jeddah governorate, Saudi Arabia. Semi-field trials were conducted at dengue mosquito research station, Dept. of Biological Sciences, faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. The efficacy of the test formulations was calculated as the number of emerging adults compared to the initial number of larvae added or the inhibition of emergence (IE%). The assessment of effectiveness was made at weekly intervals until the level of efficacy decrease to ≤50% IE. The inhibition percentage of emergence of adult for each mixture weekly in addition to the calculation of the cycle of the effective centers for each mixture. Collectively, the results of the present investigation indicate that the combination of Bactimos with Altosid or Dudim maybe promising for controlling A. aegypti mosquito larvae provided that treatments persist at least during the whole dengue transmission season.
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Affiliation(s)
- Naser A Alkenani
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80303, Jeddah 21589, Saudi Arabia
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Diédhiou SM, Konaté L, Doucouré S, Samb B, Niang EA, Sy O, Thiaw O, Konaté A, Wotodjo AN, Diallo M, Gadiaga L, Sokhna C, Faye O. [Effectiveness of three biological larvicides and of an insect growth regulator against Anopheles arabiensis in Senegal]. ACTA ACUST UNITED AC 2016; 110:102-115. [PMID: 27942991 DOI: 10.1007/s13149-016-0531-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/07/2016] [Indexed: 11/30/2022]
Abstract
Urban malaria is a major public health problem in Africa. In Senegal, the environmental changes seem to favor the persistence of malaria transmission in Dakar suburbs by creating, throughout the year, potential breeding sites of malaria vectors. In such a situation and in a context of a growing threat of insecticide resistance in anopheline vectors, the larval control making use of products from biological origin or growth regulators could represent an additional tool to the current strategies developed against anophelines. In this study conducted in 2012, the efficiency and residual effect of three biological larvicides (VectoBac® WG, Vecto-Max® CG, and VectoBac® GR) and an insect growth regulator (MetaLarv™) were evaluated on Anopheles gambiae s.l. larvae in seminatural conditions (experimental station) and natural breeding sites in the suburbs of Dakar. The formulations were tested according to the manufacturer recommendations, namely 0.03 g/m2 for VectoBac® WG, 0.5 g/m2 for VectoBac® GR, 0.75 g/m2 for VectoMax® CG, and 0.5 g/m2 for MetaLarv™. In experimental station, the treatment with larvicides was effective over a period of 14 days with a mortality ranging between 92% and 100%. The insect growth regulator remained effective up to 55 days with a single emergence recorded in the 27th day after treatment. In natural conditions, a total effectiveness (100% mortality) of larvicides was obtained 48 hours after treatment, then a gradual recolonization of breeding sites was noted. However, the insect growth regulator has reduced adult emergence higher than 80% until the end of follow-up (J28). This study showed a good efficiency of the larvicides and of the growth regulator tested. These works provide current data on potential candidates for the implementation of larval control interventions in addition to that of chemical adulticide for control of urban malaria.
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Affiliation(s)
- S M Diédhiou
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal. .,Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal.
| | - L Konaté
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - S Doucouré
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - B Samb
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - E A Niang
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - O Sy
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - O Thiaw
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal.,Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - A Konaté
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - A N Wotodjo
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - M Diallo
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
| | - L Gadiaga
- Programme national de lutte contre le paludisme, Dakar, Sénégal
| | - C Sokhna
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (Urmite), IRD, UMR 198, CNRS 6236, Inserm 1095, Aix-Marseille-Université Campus UCAD-IRD, BP 1386, CP 18524, Dakar, Sénégal
| | - O Faye
- Laboratoire d'écologie vectorielle et parasitaire, faculté des sciences et techniques, université Cheikh-Anta-Diop de Dakar, Dakar, Sénégal
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Shah RM, Alam M, Ahmad D, Waqas M, Ali Q, Binyamin M, Shad SA. Toxicity of 25 synthetic insecticides to the field population of Culex quinquefasciatus Say. Parasitol Res 2016; 115:4345-51. [PMID: 27530515 DOI: 10.1007/s00436-016-5218-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 07/28/2016] [Indexed: 10/21/2022]
Abstract
The Culex quinquefaciatus Say, commonly known as the southern house mosquito, is well known for biting nuisance and vectoring of some fatal diseases. Synthetic chemicals have been relied upon as the major control measure to control mosquitoes. Therefore, we have evaluated 21 insecticides belonging to different chemical classes for their toxicity to C. quinquefaciatus females. Chlorfenapyr was the most toxic adulticide among all the tested insecticides. Among pyrethroids, deltamethrin was the least toxic adulticide, and all other have same toxicity. In case of organophosphates, the chlorpyrifos was the most toxic insecticide. Neonicotinoids such as acetamiprid, nitenpyram, and clothianidin have similar toxicity based on overlapping of 95 % confidence intervals (CI) and were more toxic when compared with the imidacloprid. The spinetoram was more toxic as compared with the spinosad (based on non-overlapping 95 % Cl). In case of ketoenoles, spirotetrament was more toxic as compared with the spiromesifen. Emamectin benzoate was the most toxic insecticide when compared with fipronil and indoxacarb. We also have tested four insect growth regulators (IGRS) including lufenuron, methoxyfenozide, pyriproxyfen, and cyromazine as larvicides. The lufenuron and pyriproxyfen have similar toxicity based upon their overlapping 95 % CI and were more toxic as compared with the methoxyfenozide and cyromazine. The methoxyfenozide was the moderately toxic among all the tested IGRS, and cyromazine was the least toxic among all the tested IGRS. These results will prove helpful in effectuating an effective integrated vector management program for C. quinquefaciatus.
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Samuel M, Oliver SV, Coetzee M, Brooke BD. The larvicidal effects of black pepper (Piper nigrum L.) and piperine against insecticide resistant and susceptible strains of Anopheles malaria vector mosquitoes. Parasit Vectors 2016; 9:238. [PMID: 27117913 DOI: 10.1186/s13071-016-1521-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/20/2016] [Indexed: 11/15/2022] Open
Abstract
Background Insecticide resistance carries the potential to undermine the efficacy of insecticide based malaria vector control strategies. Therefore, there is an urgent need for new insecticidal compounds. Black pepper (dried fruit from the vine, Piper nigrum), used as a food additive and spice, and its principal alkaloid piperine, have previously been shown to have larvicidal properties. The aim of this study was to investigate the larvicidal effects of ground black pepper and piperine against third and fourth instar Anopheles larvae drawn from several laboratory-reared insecticide resistant and susceptible strains of Anopheles arabiensis, An. coluzzii, An. gambiae, An. quadriannulatus and An. funestus. Methods Larvae were fed with mixtures of standard larval food and either ground black pepper or piperine in different proportions. Mortality was recorded 24 h after black pepper and 48 h after piperine were applied to the larval bowls. Results Black pepper and piperine mixtures caused high mortality in the An. gambiae complex strains, with black pepper proving significantly more toxic than piperine. The An. funestus strains were substantially less sensitive to black pepper and piperine which may reflect a marked difference in the feeding habits of this species compared to that of the Gambiae complex or a difference in food metabolism as a consequence of differences in breeding habitat between species. Conclusions Insecticide resistant and susceptible strains by species proved equally susceptible to black pepper and piperine. It is concluded that black pepper shows potential as a larvicide for the control of certain malaria vector species.
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Ali MS, Ravikumar S, Beula JM. Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae. Asian Pac J Trop Biomed 2015; 2:570-3. [PMID: 23569973 DOI: 10.1016/s2221-1691(12)60099-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/03/2011] [Accepted: 12/03/2011] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE To identify the larvicidal activity of the seagrass extracts. METHODS Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg - 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality - % of control mortality)/(100 - % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. RESULTS : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0 604 ± 0.0 040)µg/mL with lower confidence limit (LCL) - upper confidence limit (UCL) = (0.051-0.071) and LC90=0.0 972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R(2)= 0.909) and Y= 2.066 + 1.21x (R(2) =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars. CONCLUSIONS From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity.
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Affiliation(s)
- M Syed Ali
- School of Marine Sciences, Division of Marine Microbiology and Medicine, Department of Oceanography and Costal Area Studies, Alagappa University, Thondi Campus, Thondi-623409, Tamil Nadu, India
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Fayemiwo KA, Adeleke MA, Okoro OP, Awojide SH, Awoniyi IO. Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes. Asian Pac J Trop Biomed 2014; 4:30-4. [PMID: 24144127 DOI: 10.1016/S2221-1691(14)60204-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 11/16/2013] [Accepted: 12/22/2013] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris (P. sylvestris) and Syzygium aromaticum (S. aromaticum) against Aedes aegypti (A. aegypti) and Culex quinquefasciatus (C. quinquefasciatus). METHODS The chemical composition of the essential oils of both plants was determined using GC-MS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A. aegypti and C. quinquefasciatus in accordance with the standard protocol. RESULTS The results as determined by GC-MS showed that oil of S. aromaticum has eugenol (80.5%) as its principal constituent while P. sylvestris has 3-Cyclohexene-1-methanol, .alpha., .alpha.4-trimethyl (27.1%) as its dominant constituent. Both oils achieved over 85% larval mortality within 24 h. The larvae of A. aegypti were more susceptible to the oils [LC50 (S. aromaticum)=92.56 mg/L, LC50(P. sylvestris)=100.39 mg/L] than C. quinquefasciatus [LC50(S. aromaticum)=124.42 mg/L; LC50(P. sylvestris)=128.00 mg/L]. S. aromaticum oil was more toxic to the mosquito larvae than oil of P. sylvestris but the difference in lethal concentrations was insignificant (P>0.05). CONCLUSION The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control.
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