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Worldwide, billions of people are at risk from viruses, parasites and bacteria transmitted by mosquitoes, ticks, fleas and other vectors. Over exploitation of chemical pesticides to overcome the mosquito borne diseases led to detrimental effects on environment and human health. The present research aims to explore bio-fabrication of metal silver nanomaterials using Rhazya stricta extract against deadly mosquito vectors and microbial pathogens. The phytochemical profile of the R. stricta extracts was studied by HPLC-MS and 1 H NMR. Further, confirmation of the bio-fabricated silver nanoparticles (AgNPs) was carried out by UV-vis spectroscopy and characterization through FTIR, TEM, EDX, and XRD analyses. The R. stricta-fabricated AgNPs showed acute toxicity on key mosquito vectors from two different country (India and Kingdom of Saudi Arabia, KSA) strains, notably, with LC 50 values of 10.57, 11.89 and 12.78 μg/ml on malarial, dengue and filarial key Indian strains of mosquito vectors, respectively, and 30.66 and 38.39 μg/ml on KSA strains of Aedes aegypti and Culex pipiens, respectively. In mosquito adulticidal activity, R. stricta extract alone exhibited LC 50 values ranging from 304.34 to 382.45 μg/ml against Indian strains and from 738.733 to 886.886 against Saudi Arabian strains, while AgNPs LC 50 boosted from 9.52 to 12.16 μg/ml and from 30.66 to 38.39 μg/ml, respectively. Moreover, it was noticed that at low concentration the tested AgNPs showed high growth retardation of important pathogenic bacteria such as Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi with inhibition zone diameters from 11.86 to 22.92 mm. In conclusion, the present study highlighted that R. stricta-fabricated AgNPs could be a lead material for the management of mosquito vector and microbial pathogens control., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The development of eco-friendly and effective insecticides is crucial for public health worldwide. Herein, we focused on the desert wormwood (Artemisia herba-alba), a plant widely used in Arabian traditional medicine, as a source of green nanoinsecticides against mosquito vectors, as well as growth inhibitors to be employed against microbial pathogens. Ag nanoparticles (AgNPs) fabricated with the A. herba-alba extract were tested on Indian and Saudi Arabian strains of Anopheles, Aedes and Culex mosquitoes. The chemical profile of the A. herba-alba extract was determined by LC-DAD-MS and 1 H NMR studies. Then, AgNPs were studied using UV-vis spectroscopy, XRD, FTIR spectroscopy, TEM, and EDX analyses. Artemisia herba-alba-synthesized AgNPs showed high larvicidal toxicity against mosquitoes from both Indian and Saudi Arabian strains. LC 50 of AgNPs against Indian strains was 9.76 μg/ml for An. stephensi, 10.70 μg/ml for Ae. aegypti and 11.43 μg/ml for Cx. quinquefasciatus, whereas against Saudi Arabian strains it was 33.58 μg/ml for Ae. aegypti and 38.06 μg/ml for Cx. pipiens. In adulticidal experiments, A. herba-alba extract showed LC 50 ranging from 293.02 to 450 μg/ml, while AgNP LC 50 ranged from 8.22 to 27.39 μg/ml. Further, low doses of the AgNPs inhibited the growth of selected microbial pathogens. Overall, A. herba-alba can be further considered as a source of phytochemicals, with special reference to saponins, for effective and prompt fabrication of AgNPs with relevant insecticidal and bactericidal activity against species of high public health importance., (Copyright © 2018. Published by Elsevier B.V.)

Mosquitoes (Diptera: Culicidae) are considered to be huge threat among millions of peoples, animals, and other living organisms in the world. Most of the vector borne diseases such as malaria, filariasis, dengue hemorrhagic fever, chikungunya, Japanese encephalitis etc., created huge impact on humans in all over the world. Vector diseases in Kingdom of Saudi Arabia are increasing day by day and their control measures taken through the government sectors for eradicating the vectors helps in controlling the diseases but still more approaches to be implemented or assimilated. Most of the synthetic or chemical based insecticides to control mosquitoes developed resistance among their communities even though they showed their potential in controlling the vector in initial days. Botanical insecticides from plant‐based origin such as active compounds, essential oils, green synthesized nanomaterials, and microbial secondary metabolites helps more efficiency in controlling vectors. Mode of action against vectors differs based on its persisting active ingredients, such as larvicidal, pupicidal, adulticidal, oviposition, morphological changes etc. Even though number of research works has been carried out against mosquito species, there is only limited number of studies undergone against mosquito vectors from Saudi Arabia origin. Hence this review will give us the current knowledge on the effectiveness of botanical insecticides against major mosquito vectors from Saudi Arabia. Thus, it gives more significant against medical and veterinary sectors. [ABSTRACT FROM AUTHOR]

Mosquitoes serve as reservoirs for viruses and other microorganisms, posing a significant health‐related issue for both humans as well as livestock. Control of these deadly disease‐producing mosquito vectors is of paramount importance. The chemical analysis of Parmotrema reticulatum was examined by GC–MS. Further, lichen‐mediated AgNPs were confirmed through UV–vis spectrophotometry, FTIR, TEM‐EDX, and XRD. After 24 h post‐treatment, the lichen‐synthesized AgNPs showed considerable toxicity against distinct Aedes aegypti instars with LC50 values of 44.61 (I instar), 51.27 (II instars), 61.34 (III instars), 72.95 (IV instar), and 89.84 (pupae) μg/mL, respectively. Further, both P. reticulatum extract and AgNPs greatly reduced the survival and reproductive efficiency of A. aegypti adults. Eventually, in conventional laboratory circumstances, the predatory effectiveness of Gambusia affinis against Ae. aegypti II and III instar larvae were 71.35% and 53.40%, respectively. In antibacterial assays, low concentrations of the P. reticulatum synthesized AgNPs inhibited the development of Pseudomonas aeruginosa and Citrobacter freundii. Surface damage, ROS production, and protein leakage are the antibacterial mechanisms of AgNPs. Overall, the lichen‐derived AgNPs can be regarded as newer and safer Ae. aegypti control instruments. [ABSTRACT FROM AUTHOR]

Mosquitoes act as vectors for several deadly diseases that have devastating effect on millions of people throughout the world. Controlling the spread of these mosquito vectors is a challenging task. Here, we propose a mangrove-mediated production of AgNPs from cheap aqueous extracts of Heritiera fomes from the Sundarbans UNESCO World Heritage Site against mosquito vectors and bacterial pathogen. The bio-fabricated AgNPs were analyzed using UV–vis spectroscopy, Transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The fabricated Ag nanocomposites were crystalline and spherical shaped. Our experimental results indicated that minimal doses of H. fomes extract and H. fomes-AgNPs exhibited excellent toxicity against Anopheles stephensi as well as the Aedes aegypti with the LC50 of AgNPs ranging from 7.44 ppm (I instar) to 15.61 ppm (pupae) for A. stephensi and 8.39 ppm (I instar) to 17.66 ppm for A. aegypti. In antibacterial assays, then mangrove fabricated-AgNPs also highly inhibited the growth of B. subtilis, K. pneumoniae, and S. typhi in low doses. Overall, this study highlighted that H. fomes extracts and H. fomes-mediated Ag nanomaterials could be potentially applied for dengue, Zika and malaria vector control operations. [ABSTRACT FROM AUTHOR]

Mosquitoes are insects of huge public health importance, since they act as vectors for important pathogens and parasites. Here, we focused on the possibility of using the neem cake in the fight against mosquito vectors. The neem cake chemical composition significantly changes among producers, as evidenced by our HPTLC (High performance thin layer chromatography) analyses of different marketed products. Neem cake extracts were tested to evaluate the ovicidal, larvicidal and adulticidal activity against the rural malaria vector Anopheles culicifacies. Ovicidal activity of both types of extracts was statistically significant, and 150 ppm completely inhibited egg hatching. LC50 values were extremely low against fourth instar larvae, ranging from 1.321 (NM1) to 1.818 ppm (NA2). Adulticidal activity was also high, with LC50 ranging from 3.015 (NM1) to 3.637 ppm (NM2). This study pointed out the utility of neem cake as a source of eco-friendly mosquitocides in Anopheline vector control programmes. [ABSTRACT FROM AUTHOR]

Mosquitoes act as vectors of devastating pathogens and parasites, representing a key threat for millions of humans and animals worldwide. The control of mosquito-borne diseases is facing a number of crucial challenges, including the emergence of artemisinin and chloroquine resistance in Plasmodium parasites, as well as the presence of mosquito vectors resistant to synthetic and microbial pesticides. Therefore, eco-friendly tools are urgently required. Here, a synergic approach relying to nanotechnologies and biological control strategies is proposed. The marine environment is an outstanding reservoir of bioactive natural products, which have many applications against pests, parasites, and pathogens. We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles (AgNP) using the spongeweed Codium tomentosum, acting as a reducing and capping agent. AgNP were characterized by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In mosquitocidal assays, the 50 % lethal concentration (LC) of C. tomentosum extract against Anopheles stephensi ranged from 255.1 (larva I) to 487.1 ppm (pupa). LC of C. tomentosum-synthesized AgNP ranged from 18.1 (larva I) to 40.7 ppm (pupa). In laboratory, the predation efficiency of Mesocyclops aspericornis copepods against A. stephensi larvae was 81, 65, 17, and 9 % (I, II, III, and IV instar, respectively). In AgNP contaminated environment, predation was not affected; 83, 66, 19, and 11 % (I, II, III, and IV). The anti-plasmodial activity of C. tomentosum extract and spongeweed-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. Fifty percent inhibitory concentration (IC) of C. tomentosum were 51.34 μg/ml (CQ-s) and 65.17 μg/ml (CQ-r); C. tomentosum-synthesized AgNP achieved IC of 72.45 μg/ml (CQ-s) and 76.08 μg/ml (CQ-r). Furthermore, low doses of the AgNP inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi, using the agar disk diffusion and minimum inhibitory concentration protocol. Overall, C. tomentosum metabolites and spongeweed-synthesized AgNP may be potential candidates to develop novel and effective tools in the fight against Plasmodium parasites and their mosquito vectors. The employ of ultra-low doses of nanomosquitocides in synergy with cyclopoid crustaceans seems a promising green route for effective mosquito control programs. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the ovicidal, larvicidal and adulticidal potential of neem cake fractions of different polarity against the rural malaria vector Anopheles culicifacies (An. culicifacies). Methods: Neem cake fractions' total methanol extract (NTMeOH), total ethyl acetate extract (NTAcOEt), ethyl acetate fraction after repartition with NTMeOH (NRAcOEt), butanol fraction after repartition with NTMeOH (NRBuOH), and aqueous fraction after repartition of NTMeOH (NRH2O) were tested against An. culicifacies eggs, fourth instar larvae and adults. Results: In larvicidal experiments, NTMeOH, NTAcOEt, NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 1.32, 1.50, 1.81, 1.95 and 2.54 mg/L, respectively. All fractions tested at 150 mg/L were able to reduce egg hatchability of more than 50%, with the exception of NTAcOEt and NRAcOEt. In adulticidal assays, NTMeOH, NTAcOEt, NRAcOEt, NRBuOH and NRH2O achieved LC50 values of 3.01, 2.95, 3.23, 3.63 and 3.00 mg/L, respectively. Conclusions: Overall, this study suggests that the methanolic fractions of neem cake may be considered as a new and cheap source of highly effective compounds against the rural malaria vector An. culicifacies. [ABSTRACT FROM AUTHOR]

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum strains resistant to chloroquine. There is an urgent need to investigate new and effective sources of antimalarial drugs. This research proposed a novel method of fern-mediated synthesis of silver nanoparticles (AgNP) using a cheap plant extract of Pteridium aquilinum, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Phytochemical analysis of P. aquilinum leaf extract revealed the presence of phenols, alkaloids, tannins, flavonoids, proteins, carbohydrates, saponins, glycosides, steroids, and triterpenoids. LC/MS analysis identified at least 19 compounds, namely pterosin, hydroquinone, hydroxy-acetophenone, hydroxy-cinnamic acid, 5, 7-dihydroxy-4-methyl coumarin, trans-cinnamic acid, apiole, quercetin 3-glucoside, hydroxy-L-proline, hypaphorine, khellol glucoside, umbelliferose, violaxanthin, ergotamine tartrate, palmatine chloride, deacylgymnemic acid, methyl laurate, and palmitoyl acetate. In DPPH scavenging assays, the IC value of the P. aquilinum leaf extract was 10.04 μg/ml, while IC of BHT and rutin were 7.93 and 6.35 μg/ml. In mosquitocidal assays, LC of P. aquilinum leaf extract against Anopheles stephensi larvae and pupae were 220.44 ppm (larva I), 254.12 ppm (II), 302.32 ppm (III), 395.12 ppm (IV), and 502.20 ppm (pupa). LC of P. aquilinum-synthesized AgNP were 7.48 ppm (I), 10.68 ppm (II), 13.77 ppm (III), 18.45 ppm (IV), and 31.51 ppm (pupa). In the field, the application of P. aquilinum extract and AgNP (10 × LC) led to 100 % larval reduction after 72 h. Both the P. aquilinum extract and AgNP reduced longevity and fecundity of An. stephensi adults. Smoke toxicity experiments conducted against An. stephensi adults showed that P. aquilinum leaf-, stem-, and root-based coils evoked mortality rates comparable to the permethrin-based positive control (57, 50, 41, and 49 %, respectively). Furthermore, the antiplasmodial activity of P. aquilinum leaf extract and green-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. IC of P. aquilinum were 62.04 μg/ml (CQ-s) and 71.16 μg/ml (CQ-r); P. aquilinum-synthesized AgNP achieved IC of 78.12 μg/ml (CQ-s) and 88.34 μg/ml (CQ-r). Overall, our results highlighted that fern-synthesized AgNP could be candidated as a new tool against chloroquine-resistant P. falciparum and different developmental instars of its primary vector An. stephensi. Further research on nanosynthesis routed by the LC/MS-identified constituents is ongoing. [ABSTRACT FROM AUTHOR]

Mosquitoes (Diptera: Culicidae) serve as important vectors for a wide number of parasites and pathogens of huge medical and veterinary importance. Aedes aegypti is a primary dengue vector in tropical and subtropical urban areas. There is an urgent need to develop eco-friendly mosquitocides. In this study, silver nanoparticles (AgNP) were biosynthesized using neem cake, a by-product of the neem oil extraction from the seed kernels of Azadirachta indica. AgNP were characterized using a variety of biophysical methods, including UV-vis spectrophotometry, FTIR, SEM, EDX, and XRD analyses. Furthermore, the neem cake extract and the biosynthesized AgNP were tested for acute toxicity against larvae and pupae of the dengue vector Ae. aegypti. LC values achieved by the neem cake extract ranged from 106.53 (larva I) to 235.36 ppm (pupa), while AgNP LC ranged from 3.969 (larva I) to 8.308 ppm (pupa). In standard laboratory conditions, the predation efficiency of a Carassius auratus per day was 7.9 (larva II) and 5.5 individuals (larva III). Post-treatment with sub-lethal doses of AgNP, the predation efficiency was boosted to 9.2 (larva II) and 8.1 individuals (larva III). The genotoxic effect of AgNP was studied on C. auratus using the comet assay and micronucleus frequency test. DNA damage was evaluated on peripheral erythrocytes sampled at different time intervals from the treatment; experiments showed no significant damages at doses below 12 ppm. Overall, this research pointed out that neem cake-fabricated AgNP are easy to produce, stable over time, and can be employed at low dosages to reduce populations of dengue vectors, with moderate detrimental effects on non-target mosquito natural enemies. [ABSTRACT FROM AUTHOR]

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological niche of Cx. quinquefasciatus. [ABSTRACT FROM AUTHOR]

Mosquitoes (Diptera: Culicidae) are a key threat for millions of people worldwide, since they act as vectors for devastating pathogens and parasites. The standard method of utilisation of morphological characters becomes challenging due to various factors such as phenotypical variations. We explored the complementary approach of CO1 gene-based identification, analysing ten species of mosquito vectors belonging to three genera, Aedes, Culex and Anopheles from India. Analysed nucleotide sequences were found without pseudo genes and indels; they match with high similarity in nucleotide Basic Local Alignment Search Tool (BLASTn) search. The partial CO1 sequence of Anopheles niligricus was the first time record submitted to National Center for Biotechnology Information (NCBI). Mean intra- and interspecies divergence was found to be 1.30 and 3.83 %, respectively. The congeneric divergence was three times higher than the conspecifics. Deep intraspecific divergence was noted in three of the species, and the reason could be explained more accurately in the future by improving the sample size across different locations. The transitional and transversional substitutions were tested individually. Ts and Tv substitutions in all the 1st, 2nd and 3rd codons were estimated to be (0.44, 99.51), (40.35, 59.66) and (59.16, 40.84), respectively. Saturation of the sequences was resolved, since both the Ts and Tv exhibited a linear relationship suggesting that the sequences were not saturated. NJ and ML tree analysis showed that the individuals of the same species clustered together based on the CO1 sequence similarity, regardless of their collection site and geographic location. Overall, this study adds basic knowledge to molecular evolution of mosquito vectors of medical and veterinary importance and may be useful to improve biotechnological tools employed in Culicidae control programmes. [ABSTRACT FROM AUTHOR]

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. However, the use of synthetic insecticides to control Culicidae may lead to high operational costs and adverse non-target effects. Plant-borne compounds have been proposed for rapid extracellular synthesis of mosquitocidal nanoparticles. Their impact against biological control agents of mosquito larval populations has been poorly studied. We synthesized silver nanoparticles (AgNP) using the aqueous leaf extract of Mimusops elengi as a reducing and stabilizing agent. The formation of AgNP was studied using different biophysical methods, including UV-vis spectrophotometry, TEM, XRD, EDX and FTIR. Low doses of AgNP showed larvicidal and pupicidal toxicity against the malaria vector Anopheles stephensi and the arbovirus vector Aedes albopictus. AgNP LC against A. stephensi ranged from 12.53 (I instar larvae) to 23.55 ppm (pupae); LC against A. albopictus ranged from 11.72 ppm (I) to 21.46 ppm (pupae). In the field, the application of M. elengi extract and AgNP (10 × LC) led to 100 % larval reduction after 72 h. In adulticidal experiments, AgNP showed LC of 13.7 ppm for A. stephensi and 14.7 ppm for A. albopictus. The predation efficiency of Gambusia affinis against A. stephensi and A. albopictus III instar larvae was 86.2 and 81.7 %, respectively. In AgNP-contaminated environments, predation was 93.7 and 88.6 %, respectively. This research demonstrates that M. elengi-synthesized AgNP may be employed at ultra-low doses to reduce larval populations of malaria and arbovirus vectors, without detrimental effects on predation rates of mosquito natural enemies, such as larvivorous fishes. [ABSTRACT FROM AUTHOR]

Two of the most important challenges facing humanity in the 21st century comprise food production and disease control. Eco-friendly control tools against mosquito vectors and agricultural pests are urgently needed. Insecticidal products of marine origin have a huge potential to control these pests. In this research, we reported a single-step method to synthesize silver nanoparticles (AgNP) using the aqueous leaf extract of the seaweed Hypnea musciformis , a cheap, nontoxic and eco-friendly material, that worked as reducing and stabilizing agent during the biosynthesis. The formation of AgNP was confirmed by surface plasmon resonance band illustrated in UV–vis spectrophotometer. AgNP were characterized by FTIR, SEM, EDX and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and their mean size was 40–65 nm. Low doses of H. musciformis aqueous extract and seaweed-synthesized AgNP showed larvicidal and pupicidal toxicity against the dengue vector Aedes aegypti and the cabbage pest Plutella xylostella . The LC 50 value of AgNP ranged from 18.14 to 38.23 ppm for 1st instar larvae (L1) and pupae of A. aegypti , and from 24.5 to 38.23 ppm for L1 and pupae of P. xylostella . Both H. musciformis extract and AgNP strongly reduced longevity and fecundity of A. aegypti and P. xylostella adults. This study adds knowledge on the toxicity of seaweed borne insecticides and green-synthesized AgNP against arthropods of medical and agricultural importance, allowing us to propose the tested products as effective candidates to develop newer and cheap pest control tools. [ABSTRACT FROM AUTHOR]

Malaria, the most widespread mosquito-borne disease, affects 350-500 million people each year. Eco-friendly control tools against malaria vectors are urgently needed. This research proposed a novel method of plant-mediated synthesis of silver nanoparticles (AgNP) using a cheap seaweed extract of Ulva lactuca, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The U. lactuca extract and the green-synthesized AgNP were tested against larvae and pupae of the malaria vector Anopheles stephensi. In mosquitocidal assays, LC values of U. lactuca extract against A. stephensi larvae and pupae were 18.365 ppm (I instar), 23.948 ppm (II), 29.701 ppm (III), 37.517 ppm (IV), and 43.012 ppm (pupae). LC values of AgNP against A. stephensi were 2.111 ppm (I), 3.090 ppm (II), 4.629 ppm (III), 5.261 ppm (IV), and 6.860 ppm (pupae). Smoke toxicity experiments conducted against mosquito adults showed that U. lactuca coils evoked mortality rates comparable to the permethrin-based positive control (66, 51, and 41 %, respectively). Furthermore, the antiplasmodial activity of U. lactuca extract and U. lactuca-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. Fifty percent inhibitory concentration (IC) values of U. lactuca were 57.26 μg/ml (CQ-s) and 66.36 μg/ml (CQ-r); U. lactuca-synthesized AgNP IC values were 76.33 μg/ml (CQ-s) and 79.13 μg/ml (CQ-r). Overall, our results highlighted out that U. lactuca-synthesized AgNP may be employed to develop newer and safer agents for malaria control. [ABSTRACT FROM AUTHOR]

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 research, silver nanoparticles (AgNP) were synthesized using the aqueous extract of the seaweed Sargassum muticum. The production of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometry. AgNP were characterized by FTIR, SEM, EDX, and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and mean size was 43-79 nm. Toxicity of AgNP was assessed against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. In laboratory, AgNP were highly toxic against larvae and pupae of the three mosquito species. Maximum efficacy was observed against A. stephensi larvae, with LC ranging from 16.156 ppm (larva I) to 28.881 ppm (pupa). In the field, a single treatment with AgNP (10 × LC) in water storage reservoirs was effective against the three mosquito vectors, allowing complete elimination of larval populations after 72 h. In ovicidal experiments, egg hatchability was reduced by 100 % after treatment with 30 ppm of AgNP. Ovideterrence assays highlighted that 10 ppm of AgNP reduced oviposition rates of more than 70 % in A. aegypti, A. stephensi, and C. quinquefasciatus (OAI = −0.61, −0.63, and −0.58, respectively). Antibacterial properties of AgNP were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. AgNP tested at 50 ppm evoked growth inhibition zones larger than 5 mm in all tested bacteria. Overall, the chance to use S. muticum-synthesized AgNP for control of mosquito vectors seems promising since they are effective at low doses and may constitute an advantageous alternative to build newer and safer mosquito control tools. This is the first report about ovicidal activity of metal nanoparticles against mosquito vectors. [ABSTRACT FROM AUTHOR]

Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is the primary vector of dengue. The use of synthetic insecticides to control Aedes mosquitoes lead to high operational costs and adverse nontarget effects. In this scenario, eco-friendly control tools are a priority. We proposed a novel method to synthesize silver nanoparticles using the aqueous leaf extract of Phyllanthus niruri, a cheap and nontoxic material. The UV-vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 420 nm corresponding to the surface plasmon resonance band of nanoparticles. SEM analyses of the synthesized nanoparticles showed a mean size of 30-60 nm. EDX spectrum showed the chemical composition of the synthesized nanoparticles. XRD highlighted that the nanoparticles are crystalline in nature with face-centered cubic geometry. Fourier transform infrared spectroscopy (FTIR) of nanoparticles exhibited prominent peaks 3,327.63, 2,125.87, 1,637.89, 644.35, 597.41, and 554.63 cm. In laboratory assays, the aqueous extract of P. niruri was toxic against larval instars (I-IV) and pupae of A. aegypti. LC was 158.24 ppm (I), 183.20 ppm (II), 210.53 ppm (III), 210.53 ppm (IV), and 358.08 ppm (pupae). P. niruri-synthesized nanoparticles were highly effective against A. aegypti, with LC of 3.90 ppm (I), 5.01 ppm (II), 6.2 ppm (III), 8.9 ppm (IV), and 13.04 ppm (pupae). In the field, the application of silver nanoparticles (10 × LC) lead to A. aegypti larval reduction of 47.6 %, 76.7 % and 100 %, after 24, 48, and 72 h, while the P. niruri extract lead to 39.9 %, 69.2 % and 100 % of reduction, respectively. In adulticidal experiments, P. niruri extract and nanoparticles showed LC and LC of 174.14 and 6.68 ppm and 422.29 and 23.58 ppm, respectively. Overall, this study highlights that the possibility to employ P. niruri leaf extract and green-synthesized silver nanoparticles in mosquito control programs is concrete, since both are effective at lower doses if compared to synthetic products currently marketed, thus they could be an advantageous alternative to build newer and safer tools against dengue vectors. [ABSTRACT FROM AUTHOR]

Mosquitoes (Diptera: Culicidae) represent an important threat to millions of people worldwide, since they act as vectors for important pathogens, such as malaria, yellow fever, dengue and West Nile. Control programmes mainly rely on chemical treatments against larvae, indoor residual spraying and insecticide-treated bed nets. In recent years, huge efforts have been carried out to propose new eco-friendly alternatives, with a special focus on the evaluation of plant-borne mosquitocidal compounds. Major examples are neem-based products ( Azadirachta indica A. Juss, Meliaceae) that have been proven as really effective against a huge range of pests of medical and veterinary importance, including mosquitoes. Recent research highlighted that neem cake, a cheap by-product from neem oil extraction, is an important source of mosquitocidal metabolites. In this review, we examined (i) the latest achievements about neem cake metabolomics with special reference to nor-terpenoid and related content; (ii) the neem cake ovicidal, larvicidal and pupicidal toxicity against Aedes, Anopheles and Culex mosquito vectors; (iii) its non-target effects against vertebrates; and (iv) its oviposition deterrence effects on mosquito females. Overall, neem cake can be proposed as an eco-friendly and low-cost source of chemicals to build newer and safer control tools against mosquito vectors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hazardous waste (cigarettes butts) was utilized for the synthesis of AC-Ag nanocomposite. • AC-Ag nanocomposite was confirmed by UV–vis, XRD, FTIR, HRTEM-EDAX and BET. • AC-Ag nanocomposite were extremely toxic against bacterial pathogens and mosquito vectors at lethal doses. The thread of resistance development among insects and bacterial pathogens has created the need for developing highly effective and safe drugs. In this research, we studied the toxicity of AC-Ag nanocomposite prepared from cigarette butts (CBs) on key mosquito vectors, Anopheles stephensi , Aedes aegypti and Culex quinquefasciatus , and gram-negative, gram-positive bacteria respectively. They were extremely toxic against IInd and IVth instar larvae of An. stephensi , Ae.aegypti and Cx. quinquefasciatus, notably, with LC 50 of 5.892 (IInd instar), 8.701 (IVth instar), 8.657 (IInd instar), 13.324 (IVth instar), and 13.448 (IInd instar), 17.248 μg/ml (IVth instar) on An. stephensi , Ae. aegypti and Cx. quinquefasciatus. In antibacterial assays, low doses of the CBs derived AC-Ag nanocomposite inhibited the growth of Escherichia coli and Staphylococcus aureus. The surface damage, ROS production and protein leakage are the antibacterial mechanisms of AC-Ag. This study proved that a CBs derived AC-Ag nanocomposite could be given at ultra-low doses to reduce the bacterial and mosquito larval population. [ABSTRACT FROM AUTHOR]

The present study was carried out on Solanum xanthocarpum fruit extract and copepods Mesocyclops thermocyclopoides, which were assessed for the control of dengue vector, Aedes aegypti, under laboratory conditions. The medicinal plants were collected from the outskirts of Bharathiar University, Coimbatore, Tamil Nadu, India. The shade-dried fruit materials were extracted by employing the Soxhlet apparatus with methanol (organic solvent) 8 h and the extracts were filtered through a Buchner funnel with Whatman number 1 filter paper. The fruit extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4°C. S. xanthocarpum fruit extract (SXFE) at 100, 150, 200, 250, and 300 ppm caused significant mortality of Ae. aegypti. The LC and LC of S. xanthocarpum against the first to fourth instar larvae and pupae were 170.91, 195.07, 221.45, 253.18, and 279.52 ppm and 320.62, 366.48, 410.20, 435.16, and 462.10 ppm, respectively. A study was conducted to test whether the predatory efficiency of copepods on first instars changed in the presence of SXFE. The percentage of predatory efficiency of copepod was 6.5 % in treatments without SFXE and the percentage of predatory efficiency increased up to 8.7 % when copepods were combined with SFXE. This increase in predation efficiency may be caused by detrimental effects of the SFXE active principle compound (solanocarpine and solanocarpidine) on the mosquito larvae. Repeated application of fruit extract of S. xanthocarpum does not cause changes in copepod populations because fruit extract is highly degradable in the environment. Therefore, the present investigation clearly exhibits that the fruit extract of S. xanthocarpum and copepod M. thermocyclopoides could serve as a potential of highest mortality rate against the mosquito larvae under laboratory conditions. This is a new eco-friendly approach for the control of Ae. aegypti mosquito as target species. Therefore, this study provides the first report on the combined effect of mosquitocidal activity of this fruit extract and copepods of M. thermocyclopoides against dengue vector Ae. aegypti from India. [ABSTRACT FROM AUTHOR]

The development of parasites and pathogens resistant to synthetic drugs highlighted the needing of novel, eco-friendly and effective control approaches. Recently, metal nanoparticles have been proposed as highly effective tools towards cancer cells and Plasmodium parasites. In this study, we synthesized silver nanoparticles (EW–AgNP) using Eudrilus eugeniae earthworms as reducing and stabilizing agents. EW–AgNP showed plasmon resonance reduction in UV–vis spectrophotometry, the functional groups involved in the reduction were studied by FTIR spectroscopy, while particle size and shape was analyzed by FESEM. The effect of EW–AgNP on in vitro HepG2 cell proliferation was measured using MTT assays. Apoptosis assessed by flow cytometry showed diminished endurance of HepG2 cells and cytotoxicity in a dose-dependent manner. EW–AgNP were toxic to Anopheles stephensi larvae and pupae, LC 50 were 4.8 ppm (I), 5.8 ppm (II), 6.9 ppm (III), 8.5 ppm (IV), and 15.5 ppm (pupae). The antiplasmodial activity of EW–AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum . EW–AgNP IC 50 were 49.3 μg/ml (CQ-s) and 55.5 μg/ml (CQ-r), while chloroquine IC 50 were 81.5 μg/ml (CQ-s) and 86.5 μg/ml (CQ-r). EW–AgNP showed a valuable antibiotic potential against important pathogenic bacteria and fungi. Concerning non-target effects of EW–AgNP against mosquito natural enemies, the predation efficiency of the mosquitofish Gambusia affinis towards the II and II instar larvae of A. stephensi was 68.50% (II) and 47.00% (III), respectively. In EW–AgNP-contaminated environments, predation was boosted to 89.25% (II) and 70.75% (III), respectively. Overall, this research highlighted the EW–AgNP potential against hepatocellular carcinoma, Plasmodium parasites and mosquito vectors, with little detrimental effects on mosquito natural enemies. [ABSTRACT FROM AUTHOR]

Plant-borne compounds can be employed to synthesize mosquitocidal nanoparticles that are effective at low doses. However, how they affect the activity of mosquito predators in the aquatic environment is unknown. In this study, we synthesized gold nanoparticles (AuN) using the leaf extract of Cymbopogon citratus , which acted as a reducing and capping agent. AuN were characterized by a variety of biophysical methods and sorted for size in order to confirm structural integrity. C. citratus extract and biosynthesized AuN were tested against larvae and pupae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti. LC 50 of C. citratus extract ranged from 219.32 ppm to 471.36 ppm. LC 50 of AuN ranged from 18.80 ppm to 41.52 ppm. In laboratory, the predatory efficiency of the cyclopoid crustacean Mesocyclops aspericornis against A. stephensi larvae was 26.8% (larva I) and 17% (larva II), while against A. aegypti was56% (I) and 35.1% (II). Predation against late-instar larvae was minimal. In AuN-contaminated environment,predation efficiency against A. stephensi was 45.6% (I) and 26.7% (II), while against A. aegypti was 77.3% (I) and 51.6% (II). Overall, low doses of AuN may help to boost the control of Anopheles and Aedes larval populations in copepod-based control programs. [ABSTRACT FROM AUTHOR]

Marine algae contain many bioactive constituents. In the current research, the brown seaweed Sargassum muticum was collected from Red Sea and its extract used as a capping agent for the formulation of biocompatible stable silver nanoparticles (AgNPs). The seaweed-fabricated AgNPs were studied through UV–vis, TEM, XRD, EDX, FTIR and Zeta potential analyses. The chemical constituents of S. muticum extract were evaluated by RP-HPLC and 1H NMR. Both seaweed extract and AgNPs had mosquito larvicidal and adulticidal activities. The seaweed-fabricated AgNPs induced high larval mortality against mosquitoes from both Indian and Saudi Arabian strains when compared to the seaweed extract. The LC 50 values of AgNPs against the Indian strains of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi were 43.9, 35.9 and 27.0 μg/ml, respectively; those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 110.4 and 126.2 μg/ml, respectively. In adulticidal experiments, the LC 50 values of S. muticum -fabricated AgNPs against Indian strains of Cx. quinquefasciatus, Ae. aegypti and An. stephensi were 42.3, 34.3 and 29.7 µg/ml, respectively, whereas those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 86.4 and 120.0 µg/ml, respectively. Minimal doses of seaweed-fabricated AgNPs were highly effective in inhibiting the growth of Bacillus subtilis (11.25 mm inhibition zone), Escherichia coli (13.35 mm) , Klebsiella pneumoniae (14.24 mm) and Salmonella typhi (12.23 mm). Additionally, the seaweed extract was highly efficient to adsorb methylene blue (MB) and methyl orange (MO) dyes. In conclusion, the S. muticum extract revealed to be an effective capping agent to fabricate AgNPs to be industrially used for the control of deadly mosquito vectors and as an antimicrobial and dye adsorbent agent. [Display omitted] • Marine macroalgae, S. muticum was used as a capping agent for the synthesis of biocompatible stable AgNPs. • The phytoconstituents of seaweed extract was examined by RP-HPLC-MS, 1H NMR, and AgNPs were confirmed by UV–vis, FTIR, TEM, XRD, EDX and zeta potential analyses. • Significant larval and adult toxicity was achieved using seaweed extract and AgNPs on key mosquito vectors. • Seaweed extract and AgNPs highly inhibit the growth of all tested bacteria. • Low-cost dye adsorbent ability of seaweed extract at 0.3 g per 10 mL was obtained. [ABSTRACT FROM AUTHOR]