Mosquitocidal Properties Research Articles

Chemical composition and mosquitocidal properties of essential oil from Indian indigenous plants Ocimum tenuiflorum L. and Ocimum americanum L. against three vector mosquitoes

Mosquitoes stand out as the most perilous and impactful vectors on a global scale, transmitting a multitude of infectious diseases to both humans and other animals. The primary objective of the current research was to assess the effectiveness of EOs from Ocimum tenuiflorum L. and Ocimum americanum L. in controlling Anopheles stephensi Liston. Culex quinquefasciatus Say and Aedes aegypti L. mosquitoes. The larvae, pupae and eggs of the mosquitoes were exposed to four different concentrations (6.25–50 ppm). The tested EOs resulted in >99–100 % mortality at 120 h for the eggs of all examined mosquito species. It also showed robust larvicidal and pupicidal activity with LC50 and LC90 values of 17–39, 23–60 ppm and 46–220, and 73–412 ppm against Aedes, Culex and Anopheles mosquito species, respectively, at 24 h of treatment. The Suitability Index or Predator Safety Factor demonstrated that the EOs extracted from O. tenuiflorum L. and O. americanum L. did not cause harm to P. reticulata, D. indicus (water bug), G. affinis and nymph (dragonfly). GC-MS analysis identified the major probable constituents of the oil, including Phenol, 2-Methoxy-4-(1-Propenyl)- (28.29 %); 1-Methyl-3-(1′-Methylcyclopropyl) Cyclopentene (46.46 %); (E,E,E)-3,7,11,15-Tetramethylhexadeca-1,3,6,10,14-Pentaene (18.91 %) and 1,3-Isobenzofurandione, 3a,4,7,7a-Tetrahydro-4,7-Dimethyl (33.02 %). These constituents may play a significant role in the mosquitocidal activity of the oil. The same results were identified in the formulation prepared from the EOs. This marks the first report confirming the successful utilization of EOs derived from O. tenuiflorum L. and O. americanum L. in mosquito population control initiatives.

Development and Study of Mosquitocidal and Antibacterial Properties of Typhonium trilobatum-Synthesized ZnO NPS and their Impact on the Predation Efficiency of Guppy Poecilia reticulata against the Dengue vector, Aedes aegypti

Dengue fever is an arbovirus spread mostly by Aedes mosquitos. Every year, there is an increase in the incidence of dengue infection and transmission. As a result, the need for an effective measure remains a top concern. The current work aims to assess the effectiveness of Typhonium trilobatum leaf extract synthesized zinc oxide nanoparticles (ZnO NPs) against the Dengue vector, Aedes aegypti. We synthesized zinc nanoparticles by reducing and stabilizing it using T. trilobatum leaf extract. UV-vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, field emission scanning electron microscopy, transmission electron microscopy and EDAX analysis were used for analyzing nanoparticles. T. trilobatum leaf extract and biosynthesized ZnONPs were extremely efficient against Ae. aegypti young instars, with LC50 values ranging from 36.633 ppm (larva I) to 102.436 ppm (pupa) and 1.555 ppm (larva I) to 6.906 ppm (pupa). The predation effectiveness of Poecillia reticulata guppy fish against A. aegypti I - IV instar larvae were 49.8 and 25.9 %, respectively. Predation was 78.3 and 39.8 % in ZnO-contaminated environments, respectively. The results of T. trilobatum leaf extract synthesized ZnONPs showed considerable larvicidal action with an increase in predatory potential of the guppy fish P. reticulata. To screen the antibacterial activities of T. trilobatum leaf extract and Biosynthesized ZnO NPs against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi, the agar disk diffusion and minimum inhibitory concentration procedures were used. The biosynthesized ZnO NPs showed excellent antibacterial effects against bacterial pathogens. Overall, our study suggests that T. trilobatum leaf extract synthesized ZnO NPs could be used in mosquito control as well as the creation of novel chemotherapeutic medicines with low systemic toxicity.

Entomopathogenic fungal infection following immune gene silencing decreased behavioral and physiological fitness in Aedes aegypti mosquitoes

Entomopathogenic fungi are a promising category of biocontrol agents with mosquitocidal properties. Prior studies have proved their potential to reduce fecundity, human biting and vector competence, all of them together determine vectorial capacity of the mosquitoes. Unfortunately, conventional vector control strategies are inadequate with growing problem of insecticide resistance and environmental deterioration. Therefore, alternate vector control measures are immediately needed and to accomplish that, an improved understanding of behavioral and physiological defense mechanisms of the mosquitoes against fungal infection is essential. In this study, fitness was considered with respect to different behavioral (self-grooming and flight), physiological (antifungal activity and antimicrobial peptides) parameters and survival rates as compared to the control group. We found a significant upregulation in CLSP2, TEP22, Rel1 and Rel2 genes at multiple time periods of fungal infection, which indicates the successful fungal infection and activation of Toll and IMD pathways in mosquitoes. RNAi-mediated silencing of Rel1 and Rel2 genes (transcription factors of Toll and IMD pathways, respectively) significantly reduced the survival, self-grooming frequencies and durations, and flight locomotor activity among adult Ae. aegypti female mosquitoes. Moreover, Rel1 and Rel2 knockdown significantly decreased antifungal activity and antimicrobial peptides expression levels in target mosquitoes. These results indicate an overall decrease in fitness of the mosquitoes after fungal challenge following Rel1 and Rel2 silencing. These findings provide an improved understanding of behavioral and physiological responses in mosquitoes with altered immunity against entomopathogenic fungal infections which can guide us towards the development of novel biocontrol strategies against mosquitoes.

Toxicity of <i>Sargassum wightii</i> to the Malaria Vector <i>Anopheles stephensi</i> Liston (Diptera: Culicidae)

Seaweed based pesticides exhibit mosquitocidal properties and are found to be effective, biodegradable and non-toxic to non-target organisms. Sargassum wightii Greville butanol and ethanol extracts were tested for its toxicity against the second and third instar larvae of Anopheles stephensi Liston in the present study. One hundred percent larval mortality was observed in the second instar of An. stephensi by the ethanol extract at the highest concentration of 500 mg/ l after 24 hours of exposure. The LC50 values of S. wightii butanol and ethanol extracts were 107.03 and 89.67 mg/ l, against the second instar of An. stephensi; and 132.56 and 92.00 mg/ l against the third instar of An. stephensi respectively. Phytochemical analysis of S. wightii extracts revealed presence of alkaloids, carbohydrates, fatty acids, flavonoids, phenols, proteins, tannins and terpenes. Larval mortality of second and third instars of An. stephensi can be attributed to the major compounds present in S. wightii revealed by GC-MS analysis, viz., ethyl salicylate, methyl salicylate, ethyl palmitate, palmitic acid, oleic acid, phytolin and diethyl phthalate. The present study accentuates S. wightii butanol and ethanol extracts to cause lethal effects to the second and third instar larvae of An. stephensi.

Potential application of chitosan stabilized silver nanoparticles for simultaneous control of dengue virus and mosquito vectors

Dengue fever pandemic caused by dengue virus has been claimed for many lives, however, no specific treatment is available. Prevention based on vector control posed to be the most effective measure so far. The application of chitosan stabilized silver nanoparticle (AgNPs) to control larvae and adult mosquitoes has recently discovered, but their ability to inhibit Dengue virus has scarcely discussed. In this study, chitosan stabilized AgNPs have been prepared and tested against dengue virus type 1. The results showed that chitosan stabilized AgNPs can inhibit 96.66% and 98.33% dengue virus type 1 at 12.50 ppm and 25.00 ppm, respectively, without any toxicity to BHKFcɣ cells. This study confirms that chitosan stabilized AgNPs have a highly antiviral ability against dengue virus in addition to its mosquitocidal properties. This allows one to control both virus and vector simultaneously. The study suggested that chitosan stabilized AgNPs could be an effective tool to prevent the dengue epidemic.

Development of Plant-Based Larvicide and Herbal Mosquito Repellent Fast Card with Reference to Identification of the Functional Bioactive Compounds Effective Against Culex Mosquito.

Warm and humid climate creates ideal conditions for mosquito breeding. The ability of these vectors to spread a number of diseases to humans causes millions of deaths every year. Indiscriminate use of synthetic insecticides leads to the development of resistance in vector mosquitoes and along with this, these pesticides cause biological magnification of toxic components and affects adversely the non-target organisms including human being. Commercially available, chemically manufactured mosquito repellent fast cards are convenient to use and quite effective but burning of such card generates a lot of smoke and might be hazardous to human health in the long run. Thus, alternative approaches are to be adopted to control the population load of vector mosquito. Like that, the present study also reveals the larvicidal effect of Duranta leaf extract against Culex mosquito. In the present study, mosquito repellent fast card has been developed by Duranta-algal mixture which has shown better result than commercially available fast card on the basis of mosquito mortality as well as the amount of gases emitted. Again, the ethanolic crude extract of Duranta leaves leads to 100% mortality of all instars (Culex pipiens) larvae at both 1000ppm and 500ppm concentration. Therefore, the active component of Duranta has also been investigated. In Duranta, highest area percentage and peak have been shown by propionic acid in the retention time 18.086 by GC-MS. So, it can be confirmed that the major active ingredient is propionic acid in Duranta which is responsible for the mosquitocidal properties. Occurrence of propionic acid in Duranta has also been confirmed by the HPLC analysis.

Evaluation of Phytochemicals and Bioactive Properties in Mangrove Associate Suaeda monoica Forssk. ex J.F.Gmel. of Indian Sundarbans.

Suaeda monoica Forssk. ex J.F.Gmel. (Amaranthaceae), a mangrove associate and ethno-medicinal herb of Indian Sundarbans, was investigated as a promising source of bioactive compounds. Various polar and nonpolar solvent extracts of the leaf and root-shoot parts of the plant exhibited antioxidant, antibacterial, antifungal, allelopathic, mosquitocidal, antihaemolytic and antidiuretic potential. Moreover, to meet pharmacological requirements, the antioxidant ability of the plant was validated by both chemical and biological analyses. Extraction yield and presence of different phytochemicals like phenolics, flavonoids, tannins and saponins were compared in various solvent-extracted fractions. Principle component analysis revealed that the antioxidant property present in different extracts maintained a positive correlation with the occurrence of polyphenols (phenolics, tannins and flavonoids). Biochemical evaluation, HPLC examination and GC–MS analysis showed a differential level of the presence of various phytochemicals in different solvent extracts. In contrast to mosquitocidal, antioxidant, antihaemolytic and phytotoxic properties which were observed to be dominant in polar solvent extracts, maximum antibacterial potency was detected in nonpolar n-hexane fractions. Overall, the plant extract is nontoxic in nature and a dose amounting to 3,000 mg/kg was well tolerated by Swiss albino mice. A combination of HPLC and GC–MS analyses showed the presence of a large number of structurally diverse phytochemicals, many of which had already been reported as insecticidal, mosquitocidal, antibacterial, herbicidal, antidiuretic, antioxidant and anti-haemolytic compounds. All these findings support that the least explored traditional edible medicinal mangrove associate S.monoica is enriched with multiple bioactive molecules and may be considered as one of the richest sources of various lead molecules of pharmaceutical importance.

Phytochemical Profiling and Mosquitocidal Properties of Grape Fruit Pedicel Extract Against Malarial, Dengue and Filarial Vectors

The dengue, malaria and filariasis are serious global disease which caused by the mosquitoes, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. These species cause high morbidity and mortality to the human population and the development of resistance to chemical insecticides resulting in rebounding vectorial capacity. Plants may be alternative sources of mosquito control agents. The GC-MS analysis of grape fruit pedicel was done and five major compounds were identified in the methanolic grape pedicel extract namely, N- Hexadecanoic Acid, 1,E-11,Z-13-Octadecatriene, 9,12- Octadecadienoic Acid, 9-Octadecynoic Acid and 6,8- Dodecadien-1-OL (6Z,8E). The mosquitocidals activity of methanol extracts from grape fruit pedicel against immature and adult of An. stephensi, Ae. aegypti and Cx. quinquefasciatus (L.) were studied. After 24 hrs the mortality was noted and Lethal Concentration (LC50) was calculated against An. stephensi, Ae. aegypti and Cx. quinquefasciatus. The LC50 of An. stephensi were 133.263ppm, 178.275ppm, 235.619ppm, 284.472ppm and 380.630ppm for I, II, III, IV Instar and pupae, respectively. Similarly, LC50 for Ae. aegypti were 89.093ppm (I Instar), 196.560ppm (II Instar), 241.043ppm (III Instar), 323.565ppm (IV Instar) and 363.515ppm (pupae) and for Cx. quinquefasciatus were 190.073ppm, 261.693ppm, 295.404ppm, 289.067ppm and 348.430ppm for I Instar, II Instar, III Instar, IV instar and Pupae, respectively. After the treatment of grape pedicel extract the percentage of egg hatchability (Ovicidal activity) was observed. No eggs were hatched out after 400ppm of three mosquito species. In ovipositional deterrent study the number of eggs laid in control and treatment water was observed and based on this the Effective Repellency (ER) was calculated. The ER ranging from 69.83% to 88.43 % for An. stephensi; 72.18% to 89.14% for Ae. aegypti; 69.66% to 88.81% for Cx. quinquefasciatus, was investigated. It is thus concluded that the grape fruit pedicel extract has an effective toxicity against An. stephensi, Ae. Aegypti and Cx. quinquefasciatus. Hence, this pedicel extract can be used as an insecticide.

Efficacy of chitosan silver nanoparticles from shrimp-shell wastes against major mosquito vectors of public health importance

AbstractMosquito-borne diseases are causing serious damage to public health worldwide, and control of these deadly mosquito vectors is a major thrust area for epidemiologists and public health workers. Therefore, the present research reports an eco-friendly solution with multipotency of silver nanoparticle fabricated from shrimp shell biowaste in controlling mosquitoes and bacterial pathogens. The biofabricated chitosan silver nanoparticles (Cs-AgNPs) were confirmed by UV-visible spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction and zeta potential analysis. The TEM studies showed that the obtained Cs-AgNPs were mostly spherical in shape. Low doses of chitosan and Cs-AgNPs showed high mosquitocidal properties against both larvae and adult ofAnopheles stephensi,Aedes aegypti, andCulex quinquefasciatus.The LC50(lethal concentration 50%) of Cs-AgNPs was 10.240 ppm (fourth instar larvae) and 9.671 ppm (adult) forAn. stephensi; 11.349 ppm (fourth instar) and 12.015 ppm (adult) forAe. aegyptiand 12.426 ppm (fourth instar) and 12.965 ppm (adult) forCx. quinquefasciatus.The concerning part of antibacterial studies showed that Cs-AgNP had significant inhibition on tested bacterial pathogens. Overall, this study shows that chitosan extracted from the shrimp shell wastes can be used as a potential source for controlling major mosquito vectors.

The aromatic ginger Kaempferia galanga L. (Zingiberaceae) essential oil and its main compounds are effective larvicidal agents against Aedes vittatus and Anopheles maculatus without toxicity on the non-target aquatic fauna

Kaempferia galangal L. (Zingiberaceae), also known as aromatic ginger, is used in the food and cosmetics, pharmaceuticals and maquillage materials, as well as in the traditional Indian medicine. The essential oil (EO) obtained from its rhizome by hydrodistillation is of economic interest and contains ethyl p-methoxycinnamate as the main component, which is used as an anticancer, antimicrobial, skin protector and whiteneing and nematicidal agent. To our knowledge, the mosquitocidal properties of the aromatic ginger EO have hitherto been poorly investigated. Therefore, in the present work, we tested this EO and its major chemical constituents (MCCs), namely ethyl p-methoxycinnamate, trans-ethyl cinnamate and trans-cinnamaldehyde for their larval toxicity on Aedes vittatus and Anopheles maculatus. The EO chemical composition, studied by GC-MS analysis, was made up of 39 compounds, with ethyl p-methoxycinnamate (30.6%), trans-ethyl cinnamate (26.8%) and trans-cinnamaldehyde (11.5%) as the major constituents. The EO and its MCCs showed LC50 values of 39.22, 10.36, 28.26 and 36.35 μg/ml on Ae. vittatus, and of 41.36, 12.56, 30.23 and 38.47 μg/ml on An. maculatus third instar larvae, respectively. The ecofriendliness of EO and MCCs on the aquatic fauna was demonstrated as they were safe to Anisops bouvieri, Acilius sulcatus and Gambusia affinis. Our findings showed that the K. galanga rhizome EO and its MCCs are promising larvicidal agents without affecting non-target organisms (NTOs). They also give news insights into the potential economic exploitation of this EO and its MCCs in the fabrication of effective and eco-friendly mosquitocidal formulations.

Mosquitocidal and Anti-Inflammatory Properties of The Essential Oils Obtained from Monoecious, Male, and Female Inflorescences of Hemp (Cannabis sativa L.) and Their Encapsulation in Nanoemulsions.

Among the various innovative products obtainable from hemp (Cannabis sativa L.) waste biomass originating from different industrial processes, the essential oil (EO) deserves special attention in order to understand its possible application in different fields, such as cosmetics, pharmaceuticals, and botanical insecticides. For the purpose, in the present work, we studied the chemical composition of EOs obtained from different hemp varieties, namely Felina 32 and Carmagnola Selezionata (CS) using monoecious, male, and female inflorescences, and we evaluated their mosquitocidal activities on larvae and pupae of two main malaria vectors, Anopheles gambiae and An. stephensi. Then, in order to evaluate the safe use of hemp EOs for operators, the potential pro- or anti-inflammatory effect of hemp EOs together with their toxicological profile were determined on dermal fibroblasts and keratinocytes. Given the promising results obtained by insecticidal and anti-inflammatory studies, a preliminary evaluation of EOs encapsulation into nanoemulsions (NEs) has been performed with the aim to develop a formulation able to improve their poor physicochemical stability. Felina 32 and CS inflorescences provided EOs with an interesting chemical profile, with monoterpene and sesquiterpene hydrocarbons as the major components. This study highlighted the potential application of male inflorescences, which are usually discharged during hemp product processing. These EOs could be exploited as potential sustainable and eco-friendly insecticides, given their capability to be toxic against mosquitoes and the possibility to use them to prepare stable and safe formulations. The LC50 values found in this study (<80 ppm) are lower, on average, than those of many plant EOs, with the advantage of using an industrial waste product. From MTT assay and gene and protein expression analysis, EOs showed no cytotoxicity at the appropriate doses and exerted an anti-inflammatory effect on the human cell lines tested. These findings encourage further applied research on hemp EOs in order support their industrial exploitation.

Phytochemical profiling and biological activity of Plectranthus amboinicus (Lour.) mediated by various solvent extracts against Aedes aegypti larvae and toxicity evaluation

Objective: To analyze the phytochemical compounds and to investigate the bio-toxic efficacy of various solvent extracts of Plectranthus amboinicus against mosquito larvae activity and lethality on non-targeting organisms. Methods: The methanol, ethyl acetate, hexane, and aqueous extracts of Plectranthus amboinicus were subjected to analyze the mosquitocidal activity against the dengue vector, Aedes aegypti and toxicity assays on zebra fish and brine shrimp. Three replications were performed, and negative control was also maintained. Amongst, ethyl acetate extract of Plectranthus amboinicus was chosen for the determination of bio-active compounds. Results: The mosquitocidal assays of methanol and ethyl acetate extracts of Plectranthus amboinicus showed the maximal activity with minimal concentration against the 4th instar mosquito-larvae of Aedes aegypti through the following lethal concentration (LC50 and LC90) values: 53.36 & 92.51 μg/mL and 13.64 & 86.09 μg/mL, respectively. In addition, the plant extracts showed no toxicity on zebra fish embryo and brine shrimp assays. The gas-chromatography analysis of the ethyl acetate extract of Plectranthus amboinicus revealed the presence of seven different compounds. Among them, PAEA-fraction 60 contained a major active bioactive compound, hexadecanoic acid, methyl ester (270.0). Conclusions: Plectranthus amboinicus possesses mosquitocidal properties and could be used as a potential alternative source for preparing the mosquitocidal agents.

Biological evaluation of a series of benzothiazole derivatives as mosquitocidal agents

AbstractAedes aegypti is associated with the transmission of numerous human and animal diseases, such as yellow fever, dengue fever, chikungunya, and more recently Zika virus. Emerging insecticide resistance has created a need to develop new mosquitocidal agents for effective control operations. A series of benzothiazole-piperidine derivatives (1-24) were investigated for their larvicidal and adulticidal effects on Ae. aegypti It was observed that compounds 2, 4, 6, 7, 8, 11 and 13 showed notable larvicidal activity. Furthermore, compounds 6 and 10 showed promising adulticidal activity. Based on the mosquitocidal properties of these compounds, docking studies were also carried out in the active site of the AeSCP2 enzyme to explore any insights into further in vitro enzyme studies. Docking results indicated that all these active compounds showed reasonable interactions with critical residues in the active site of this enzyme. This outcome suggested that these compounds might show their larvicidal and adulticidal effects via the inhibition of AeSCP2. According to in vitro and in silico studies, compounds 2, 4, 6, 7, 8, 10, 11 and 13 stand out as candidates for further studies.

Antioxidant, anticoagulant and mosquitocidal properties of water soluble polysaccharides (WSPs) from Indian seaweeds

Abstract Water Soluble Polysaccharides (WSP) from three selected Indian seaweeds were extracted and fractionated by Ion Exchange Chromatography (IEC) to yield fractionated polysaccharides (FPs). Structural characterization of the FPs was performed using FT-IR and UV-Visible spectroscopy and the antioxidant properties were evaluated by total antioxidant, 2,2 diphenyl-1-picrylhydrazyl (DPPH) and Hydrogen Peroxide radical scavenging (H2O2) assays. FPs from Gracilaria filiforms demonstrated higher glucose, protein, moisture and essential mineral compositions. FPs from Gracilaria filiforms also exhibited higher scavenging activities in all the antioxidant assays. FPs from all the three seaweeds exhibited commendable anticoagulant activities. FPs from Gracilaria filiforms exhibited the maximum larvicidal activity on Anopheles stephensi (LC50 = 0.255867 mg/L) followed by Turbinaria conoides on Aedes aegypti (LC50 = 0.174348 mg/L) and Enteromorpha compressa on Culex quinquefasciatus (LC50 = 0.11175 mg/L). The results strongly establish the potentials of the FPs from the three selected Indian seaweeds as alternate functional foods and nutraceutical entities as well as mosquitocidal agents in future.

Urolithiasis: Population analysis and composition

Kaempferia galangal L. (Zingiberaceae), also known as aromatic ginger, is used in the food and cosmetics, pharmaceuticals and maquillage materials, as well as in the traditional Indian medicine. The essential oil (EO) obtained from its rhizome by hydrodistillation is of economic interest and contains ethyl p-methoxycinnamate as the main component, which is used as an anticancer, antimicrobial, skin protector and whiteneing and nematicidal agent. To our knowledge, the mosquitocidal properties of the aromatic ginger EO have hitherto been poorly investigated. Therefore, in the present work, we tested this EO and its major chemical constituents (MCCs), namely ethyl p-methoxycinnamate, trans-ethyl cinnamate and trans-cinnamaldehyde for their larval toxicity on Aedes vittatus and Anopheles maculatus. The EO chemical composition, studied by GC-MS analysis, was made up of 39 compounds, with ethyl p-methoxycinnamate (30.6%), trans-ethyl cinnamate (26.8%) and trans-cinnamaldehyde (11.5%) as the major constituents. The EO and its MCCs showed LC50 values of 39.22, 10.36, 28.26 and 36.35 μg/ml on Ae. vittatus, and of 41.36, 12.56, 30.23 and 38.47 μg/ml on An. maculatus third instar larvae, respectively. The ecofriendliness of EO and MCCs on the aquatic fauna was demonstrated as they were safe to Anisops bouvieri, Acilius sulcatus and Gambusia affinis. Our findings showed that the K. galanga rhizome EO and its MCCs are promising larvicidal agents without affecting non-target organisms (NTOs). They also give news insights into the potential economic exploitation of this EO and its MCCs in the fabrication of effective and eco-friendly mosquitocidal formulations.

Repellent and Mosquitocidal Properties of Smoke from Oil and Non-polar Extracts of Ocimum viride Leaf Against Aedes aegyptii

Repellent and Mosquitocidal Properties of Smoke from Oil and Non-polar Extracts of Ocimum viride Leaf Against Aedes aegyptii

Retraction Note to: Mosquitocidal properties of Bacillus species isolated from mangroves of Vellar estuary, Southeast coast of India.

[This retracts the article DOI: 10.1007/s12639-013-0371-9.].

Hypericum japonicum: a Double-Headed Sword to Combat Vector Control and Cancer.

Mosquito control with naturally derived herbal insecticides has gained much momentum, with the increased insecticide resistance of vectors and the multiple infectious diseases spread by them. Yet, recent studies also suggest that mosquitoes could probably transmit some cancerous cells or cancer-causing viruses from one individual to another between their blood meals. The current research thus focused on the screening and characterization of novel plants with both mosquitocidal and anticancerous properties. Accordingly, different solvent extracts of Hypericum japonicum, a key plant in Chinese medicine, were screened for its larvicidal efficacy using the fourth instar larvae of Aedes aegypti (major vector of Dengue and chikungunya). Methanolic extracts of the plant showed effective larvicidal property with LC50 7.37ppm and LC9011.59ppm values. The anticancerous property of the plant extract was also evaluated by in vitro cytotoxicity assay against Daltons Lymphoma Ascites (DLA) cells. The results indicated that H. japonicum plant extracts at very low concentrations of LC500.95ppm and LC901.85ppm were potent cytotoxic agents. To the best of our knowledge, this is the first and the foremost report of Hypericum japonicum as a potent mosquitocidal and anticancerous agent. Identification and characterization of such plant-derived bioactive plants thus could serve as a double-headed sword against the spread of infectious diseases and cancer.

Hydrothermal synthesis of titanium dioxide nanoparticles: mosquitocidal potential and anticancer activity on human breast cancer cells (MCF-7).

Mosquito vectors (Diptera: Culicidae) are responsible for transmission of serious diseases worldwide. Mosquito control is being enhanced in many areas, but there are significant challenges, including increasing resistance to insecticides and lack of alternative, cost-effective, and eco-friendly products. To deal with these crucial issues, recent emphasis has been placed on plant materials with mosquitocidal properties. Furthermore, cancers figure among the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases and 8.2 million cancer-related deaths in 2012. It is expected that annual cancer cases will rise from 14 million in 2012 to 22 million within the next two decades. Nanotechnology is a promising field of research and is expected to give major innovation impulses in a variety of industrial sectors. In this study, we synthesized titanium dioxide (TiO2) nanoparticles using the hydrothermal method. Nanoparticles were subjected to different analysis including UV-Vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), zeta potential, and energy-dispersive spectrometric (EDX). The synthesized TiO2 nanoparticles exhibited dose-dependent cytotoxicity against human breast cancer cells (MCF-7) and normal breast epithelial cells (HBL-100). After 24-h incubation, the inhibitory concentrations (IC50) were found to be 60 and 80 μg/mL on MCF-7 and normal HBL-100 cells, respectively. Induction of apoptosis was evidenced by Acridine Orange (AO)/ethidium bromide (EtBr) and 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining. In larvicidal and pupicidal experiments conducted against the primary dengue mosquito Aedes aegypti, LC50 values of nanoparticles were 4.02 ppm (larva I), 4.962 ppm (larva II), 5.671 ppm (larva III), 6.485 ppm (larva IV), and 7.527 ppm (pupa). Overall, our results suggested that TiO2 nanoparticles may be considered as a safe tool to build newer and safer mosquitocides and chemotherapeutic agents with little systemic toxicity.

Biosynthesis, mosquitocidal and antibacterial properties of Toddalia asiatica-synthesized silver nanoparticles: do they impact predation of guppy Poecilia reticulata against the filariasis mosquito Culex quinquefasciatus?

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this study, silver nanoparticles (AgN) were biosynthesized a cheap aqueous extract of T. asiatica leaves as reducing and stabilizing agent. The formation of nanoparticle was confirmed by surface Plasmon resonance band illustrated in UV-vis spectrophotometer. AgN were characterized by FTIR, SEM, EDX, and XRD analyses. AgN were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and their mean size was 25-30 nm. T. asiatica aqueous extract and green-synthesized AgN showed excellent larvicidal and pupicidal toxicity against the filariasis vector Culex quinqufasciatus, both in laboratory and field experiments. AgN LC50 ranged from 16.48 (I instar larvae) to 31.83 ppm (pupae). T. asiatica-synthesized were also highly effective in inhibiting growth of Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. Lastly, we evaluated if sublethal doses of nanoparticles affect predation rates of fishes, Poecilia reticulata, against C. quinquefasciatus. In AgN-contaminated environment, predation of guppies against mosquito larvae was slightly higher over normal laboratory conditions. Overall, this study highlighted that T. asiatica-synthesized AgN are easy to produce, stable over time, and may be employed at low dosages to reduce populations of filariasis vectors, without detrimental effects on predation rates of mosquito natural enemies.