Chemical constituents and strong larvicidal activity of Solanum xanthocarpum among selected plants extracts against the malaria, filaria, and dengue vectors

Background & objectives: The role of mosquitoes is instrumental in the transmission of various diseases. Mosquitoeborne diseases account for a significant share of the global burden of total infectious diseases. Vector control is the principal method for the control of these mosquito-borne diseases. Plant-derived insecticides serve as an effective alternative to chemical insecticides. The present study has been undertaken to assess the larvicidal potential of methanol and petroleum ether extracts of leaves of Solanum xanthocarpum, Parthenium hysterophorus, Manihot esculenta, and Chamaecyparis obtusa. Methods: Larvicidal activity was tested against the early four-stage instar larvae of laboratory-reared susceptible strains of the malaria vector, Anopheles stephensi, dengue fever vector, Aedes aegypti, and the lymphatic filariasis vector, Culex quinquefasciatus at 20 to 120 ppm concentrations. Further, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectroscopy (GC-MS) analyses were carried out to identify the bioactive compounds present in the methanolic leaf extracts of Solanum xanthocarpum for designing a larvicidal product in future. Results: After 72 h of exposure high larvicidal activities were observed in methanolic and petroleum ether leaves extract of S. xanthocarpum against An. stephensi, Ae. aegypti and Cx. quinquefasciatus. The larvicidal activities for methanol and petroleum ether leaf extract of S. xanthocarpum with LC50 = 09.201 and 12.435 ppm and LC90 = 21.578 and 27.418 ppm for An. stephensi; LC50 = 11.450 and 10.026 ppm and LC90 = 26.328 and 22.632 ppm for Ae. aegypti and LC50 = 12.962 and 13.325 ppm and LC90 = 26.731 and 30.409 ppm for Cx. quinquefasciatus, respectively, were found to be most effective. GC-MS analysis revealed 43 compounds, amongst these phytol (13.09%), 3-allyl-2- methoxy phenol (9.55%), (9Z, 12Z)-9, 12-octadecadienoyl chloride (7.93%), linoleic acid (5.45%), alpha-tocospiro B (5.08%) and hexadecanoic acid (4.35%) were identified as major compounds. Interpretation & conclusion: Present work showed that leaf extracts of S. xanthocarpum are a source of potential natural candidate that possess several phytochemicals which can be explored further for the development of ecologically safer mosquito control products.

Larvicidal activity of the pericarp extract of Garcinia mangostana against dengue vector Aedes aegypti in Sri Lanka

To assess the larvicidal activity of mangosteen (Garcinia mangostana) against larval stages of Aedes aegypti mosquitoes. Methods: A crude extract was prepared in ethanol from powdered mangosteen pericarps. A concentration gradient (0.01-4.92 g/ L) was prepared from the stock solution. Seven batches of 25 third instar larvae of Aedes aegypti were used for larval bioassays. Larval mortality rates were observed after one and 24 hours. Cholesterol and total lipid contents in 20 randomly selected dead larvae at each trial were assessed by colorimetric method. The experimental setup was repeated five times. The General Linear Model and Probit analysis were used to evaluate the relationship of mortality with cholesterol level, total lipid level and cholesterol to total lipid ratio. Results: The percentage mortalities significantly varied with different concentrations (F7,32=385.737; P<0.001). The LC50 and LC99 values were (0.041 0.006) g/L and (10.616 1.758) g/ L, respectively after 24 hours. There was no mortality recorded within the one-hour exposure time. Only the cholesterol content (F5,24=173.245; P<0.001) in larvae exposed to different concentrations denoted a significantly decreasing trend within 24- hour exposure. Larvae that were exposed to the lowest concentration (0.55 g/L) showed a higher cholesterol level (22.67 1.33) g. Conclusions: The Garcinia mangostana extract acts as an effective sterol carrier protein inhibitor that inhibits cholesterol uptake in Aedes aegypti mosquitoes. Hence, it could be explored for use as a key source for the development of an environment-friendly plantbased larvicide.

Tetradenia riparia leaves, flower buds, and stem essential oils to control of Aedes aegypti larvae

Abstract Tetradenia riparia (Hochst.) Codd (Lamiaceae) is a species native to the African continent and used as an insect repellent. The objective of the study was to evaluate the larvicidal potential of essential oils (EOs) from the leaves, flower buds, and stem of T. riparia, collected in winter against Aedes aegypti larvae. The EOs were extracted by hydrodistillation (3 h) and identified by GC/MS. The EOs were tested against larvae of A. aegypti at concentrations ranging from 12500 to 1.5 µg/mL for 24 h. The insecticide activity was evaluated by probit analysis, and the anticholinesterase activity was determined by bioautographic method. The results of the class projection indicated sesquiterpenes as the majority class, corresponding to 60.66% (leaves), 64.70% (flower buds) and 83.99% (stem), and the bioassays on A. aegypti larvae indicated LC50 of 1590, 675 and 665 µg/mL, respectively. The anticholinesterase activity indicated that the EO of the leaves inhibited the enzyme at a concentration of 780 µg/mL, and those from the flower buds and stem inhibited up to 1560 µg/mL. The results indicated weak activity of essential oils against A. aegypti larvae.

Larvicidal activity of plants from Myrtaceae against Aedes aegypti L. and Simulium pertinax Kollar (Diptera)

Abstract INTRODUCTION: Despite their widespread usage, synthetic insecticides and larvicides are harmful for controlling disease-causing mosquitoes owing to the development of resistance. The leaves of Eugenia astringens, Myrrhinium atropurpureum, and Neomitranthes obscura were collected from Marambaia and Grumari restingas. The safety and larvicidal efficacy of their extracts were tested against Aedes (Stegomyia) aegypti L. and Simulium (Chirostilbia) pertinax Kollar. METHODS: The dry leaves were subjected to static maceration extraction using 90% methanol. A. aegypti and S. pertinax larvae were exposed to 7.5, 12.5, and 25.0 µL/mL of the extracts (n= 30). The larvicidal activity after 24 h and 48 h, and the mortality, were determined. The median lethal concentration (CL50) was estimated by a Finney's probit model. RESULTS: M. atropurpureum and E. astringens extracts exhibited the strongest larvicidal effects against A. aegypti. M. atropurpureum extracts (25 µL/mL) caused mortalities of over 50% and 100% after 24 h and 48 h, respectively (CL50 = 11.10 and 9.68 ppm, respectively). E. astringens extracts (25 µL/mL) caused mortalities of 50% and 63.33% after 24 h and 48 h, respectively. High concentrations of N. obscura extracts induced a maximum mortality of 46.66% in A. aegypti larvae after 48 h (CL50= 25 ppm). The larvae of S. pertinax showed 100% mortality following exposure to all the plant extracts at all the tested concentrations after 24 h. CONCLUSIONS: The extracts of M. atropurpuerum exhibited the strongest larvicidal activity against A. aegypti. The larvae of S. pertinax were sensitive to all the extracts at all the tested concentrations.

Larvicidal efficacy of temephos impregnated onto kenaf cellulose nanofibre to control Aedes aegypti (Diptera: Culicidae) larvae

@# Larviciding is an effective control method in managing mosquito-borne diseases. However, most of the current larvicide formulations have raised environmental concerns due to the presence of non-biodegradable inert or carrier materials. Therefore, the utilisation of biodegradable natural cellulosic fibres has created much attention. This study aims to evaluate the application of biodegradable kenaf cellulose nanofibre (KCNF) in larvicide formulation where the larvicide, namely temephos, is impregnated onto the fibre matrix (KCNF+T). The bioefficacy of the formulation was evaluated against Aedes aegypti (A. aegypti) mosquito larvae. The presence of the temephos on the KCNF was evaluated through micromorphological analysis using a field emission scanning electron microscope (FESEM) and a transmission electron microscope (TEM), while the quantity of temephos impregnated, released, and retained on the fibres upon dispersion in water were determined using high performance liquid chromatography (HPLC). It was observed that 97% of the temephos (0.1 mg) were impregnated on the KCNF. Upon dispersion in water, 53% of the temephos were released from the KCNF+T and the retention of temephos on the KCNF+T gradually decreased to 30%, 17%, and 7% on the first, third, and fifth month, respectively. Exposure of the A. aegypti larvae to the KCNF+T at concentrations ranging between 0.006 to 0.01 mg/L was effective in killing A. aegypti larvae at 17–25 folds as compared to using the temephos without KCNF. Microscopic examination revealed the accumulation of the KCNF on the larval appendages. In conclusion, this study demonstrated that the utilisation of KCNF in pesticide formulation is an effective way of delivering the temephos to control A. aegypti mosquito larvae.

Compatibility between Leptolegnia chapmanii and diflubenzuron and neem oil for the control of Aedes aegypti / Compatibilidad de Leptolegnia chapmanii con diflubenzurón y aceite de neem parael control de Aedes aegypti

Abstract Leptolegnia chapmanii is pathogenic to mosquito larvae. The compatibility betweenL. chapmanii and two insect growth regulators (IGR), diflubenzuron and neem oil, was evaluated. L. chapmanii was grown on culture media containing different concentrations of eachIGR. The mycelial growth was significantly reduced with the highest concentrations of IGR(F6,98= 268, p < 0.05). However, the production of zoospores (F6,56= 0.93, p > 0.05) and the lar-val mortality of Aedes aegypti (F6,56= 0.95, p > 0.05) were not significantly different amongtreatments. Furthermore, the percentage of adult emergence in the presence of different con-centrations of diflubenzuron or a neem formulation was determined, and the pathogenic activityof zoospores was evaluated at the concentrations that inhibit the emergence at 30, 50 and 90%.The pathogenicity of zoospores was not significantly different among treatments (F6,14= 0.54,p > 0.05), and the larval mortalities were above 90% in all cases.

Resumen Leptolegnia chapmanii es un patógeno de larvas de mosquitos. Se evaluó la com-patibilidad entre L. chapmanii y dos reguladores del crecimiento de insectos (IGR, por sus siglasen inglés), diflubenzurón y aceite de neem. L. chapmanii creció en medios de cultivo con diferentes concentraciones de estos IGR. El crecimiento micelial fue menor con las concentraciones más altas (F6,98= 268; p < 0,05). No hubo diferencias significativas en la producción de zoosporas (F6,56= 0,93; p > 0,05) ni en la mortalidad de las larvas de Aedes aegypti (F6,56= 0,95; p > 0,05).Se determinó el porcentaje de emergencia de adultos en presencia de diferentes concentra-ciones de diflubenzurón o de un formulado a base del aceite de neem. También se evaluó lapatogenicidad de las zoosporas a las concentraciones de los IGR que inhibieron la emergenciadel 30, 50 y 90% de adultos. No hubo diferencias significativas en la actividad de las zoosporasal comparar los tratamientos (F6,14= 054; p > 0,05). La mortalidad de las larvas fue superior al90%.

Chemical composition and larvicidal activities of essential oil of Cinnamomum camphora (L. ) leaf against Anopheles stephensi

Abstract INTRODUCTION Anopheles stephensi is the main malaria vector in Southeast Asia. Recently, plant-sourced larvicides are attracting great interests. METHODS: The essential oil was extracted from the leaf of Cinnamomum camphora (L.), and a bioassay was conducted to determine the larvicidal efficacy. The chemical composition of the essential oil was determined by GC-MS analysis. RESULTS: The oil showed strong, dose-dependent larvicidal activities. The onset of larvicidal efficiency was rapid. The LC50 and LC95 were determined as 0.146% and 1.057% at 1 h, 0.031% and 0.237% at 12 h, 0.026% and 0.128% at 24 h, respectively. The oil contains 32 compounds. CONCLUSIONS The essential oil of C. camphora leaf has an excellent larvicidal potential for the control of A. stephensi.

Efficacy of Garlic Solution (Allium sativum) in Killing of Aedes SP Larva

@#Introduction: Aedes sp can transmit various diseases including dengue fever, chikungunya whose symptoms are almost similar to dengue fever. In the recent times a new case is the virus outbreak of Zika. Many efforts have been made to suppress the density of the vector populations with the control of Aedes sp mosquitoes. One of them is by using vegetable larvicides namely garlic solution (Allium sativum). Methods: This research is a pseudo experiment with posttest design with a control group. The aim of this research study is to know the effectiveness of garlic solution in killing the larva Aedes sp. This research sample is 484 tails that are bred by the researchers themselves. The concentrations used in this study were 0%, 60%, 70%, 80% and 90% with 5 repetitions. The free variable in this study is the concentration of garlic solution and the bound variable is the larva Aedes sp. Results: The results of the study using one-way ANOVA test (p = 0.001) indicate that there are differences in the larvae deaths between each concentration. Observation by using the Abbot formula at a concentration of 60% it is found to be susceptible in killing of Aedes sp larvae due to the death of larvae at 100%. Conclusion: This means there is a direct relation between the increasing concentration of garlic solution and the number of dead larvae of Aedes sp. So, garlic can be one of the alternatives in vector control that is safe for the environment.

A herbal oil in water nano-emulsion prepared through an ecofriendly approach affects two tropical disease vectors

ABSTRACT Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson, Verbenaceae, is considered a great source of a bioactive volatile oil. Due to the wide range of known chemotypes, its chemical analysis is very important. Among the several activities of this volatile oil, a potential larvicidal action against Culicidae species is highlighted. However, the low water miscibility of volatile oils limits their application in aqueous media. Oil in water nano-emulsions are in the spotlight of novelty to solve this main problem. Thus, the aim of the present study was to obtain this nanostructured system with L. alba volatile oil (citral chemotype) and evaluate its larvicidal activity against Aedes aegypti and Culex quinquefasciatus larvae. The major compounds were geranial (30.02%) and neral (25.26%). Low mean droplet size (117.0 ± 1.0 nm) and low polydispersity index (0.231 ± 0.004) were observed and no major changes were observed after seven days of storage. LC50 values against C. quinquefasciatus and A. aegypti third-instar larvae were respectively 38.22 and 31.02 ppm, while LC90 values were, respectively, 59.42 and 47.19 ppm. The present study makes use of a low energy, solvent-free and ecofriendly method with reduced costs. Thus, this paper contributes significantly to phyto-nanobiotechnology of larvicidal agents, opening perspectives for the utilization of L. alba volatile oil in integrated practices of vector control.

Biocidal potential of Eugenia pyriformis essential oil in the control of Rhipicephalus (Boophilus) microplus in the free-living cycle / Potencial biocida do óleo essencial de Eugenia pyriformis Cambess no controle de Rhipicephalus (Boophilus) microplus no ciclo de vida livre

Brazil has one of the largest commercial cattle herds in the world, which naturally coexist with an enormous number of parasitic species. Southern cattle tick, Rhipicephalus (Boophilus) microplus, is among these species, interfering with animal productivity and causing losses to the beef and dairy cattle sector. The use of chemical acaricides in the control of this mite has resulted in the emergence of resistant populations. In this sense, alternative control measures using plants as sources of botanical acaricides have shown to be effective. Eugenia pyriformis Cambess is a Brazilian plant with antioxidant and antimicrobial activity; however, there are no reports on its acaricidal activity in the literature. The present study aimed to evaluate the acaricidal and larvicidal potential of E. pyriformis leaf essential oil (EO) on southern cattle tick at different stages of the reproductive cycle. E. pyriformis leaves were collected and dried, and had their EO extracted by hydrodistillation (3h) using a modified Clevenger apparatus. Chemical analysis was performed by gas chromatography coupled with mass spectrometry (GC/MS), and 32 compounds belonging to the sesquiterpene class were identified: hydrocarbons (17.98%) and oxygenated forms (81.96%), with spathulenol (43.65%) and caryophyllene oxide (12.17%) as the most common. The EO was evaluated by the Adult Immersion Test at the concentrations (500.00 to 3.12mg/mL) in which the following parameters were measured: mortality of females (%), hatchability of eggs (%), and product efficiency (%). Larvae were assessed by the Larval Packet Test at concentrations ranging from 25.00 to 0.00004mg/mL. Lethal concentrations (LC) required for killing 50 and 99.9% of adult females and larvae were determined using Probit analysis. LC50 and LC99.9 of EO were 0.06 and 24.60mg/mL and 1,208.80 and 2,538mg/mL for larvae and adult females, respectively. Action of the EO in the free-living cycle of R. (B.) microplus larvae was another parameter assessed. To this end, the larvae were deposited in pots containing Brachiaria decumbens and, after migration to the leaf apex, a solution containing LC99.9 (24.60mg/mL) of the EO was sprayed. After 24h, 72.25% of the larvae had died, indicating stability of the EO when subjected to uncontrolled temperature and humidity conditions. The mechanism of action through which the EO killed the larvae and adult females was investigated by the Bioautographic Method, which showed inhibition of 3.15mg/mL of the EO on the acetylcholinesterase (AChE) enzyme. The results found in the present experiment indicate that E. pyriformis essential oil is an alternative in the control of southern cattle tick in the larval (parasitic) and free-living cycle (non-parasitic) stages under field conditions.(AU)

O Brasil dispõe de um dos maiores rebanhos bovinos comerciais do mundo, sendo natural que junto a esse rebanho, coexista uma enorme quantidade de espécies parasitárias; dentre estes o carrapato Rhipicephalus (Boophilus) microplus que interfere na produtividade animal, causando prejuízos à pecuária de corte e leite. A utilização de acaricidas químicos no controle deste ácaro tem causado o surgimento de populações resistentes e neste sentido, controles alternativos utilizando plantas como fontes de acaricidas botânicos têm se mostrado eficazes. Eugenia pyriformis Cambess é uma planta brasileira com atividades antioxidante e antimicrobiana, entretanto não há relatos da atividade acaricida. O objetivo do presente estudo consistiu na avaliação do potencial acaricida e larvicida do óleo essencial das folhas de E. pyriformis sobre o carrapato bovino nos diferentes estágios do ciclo reprodutivo. As folhas foram coletadas, secas e o OE extraído por hidrodestilação (3 horas) em aparelho Clevenger modificado. A análise química foi realizada por cromatografia gasosa acoplada à espectrometria de massas (CG/EM) sendo identificados 32 compostos, pertencentes à classe sesquiterpenos: hidrocarbonetos (17.98%) e oxigenados (81.96%); tendo como majoritários o spathulenol (43,65%) e caryophylene oxide (12,17%). O OE foi avaliado pelo teste de imersão de adultos nas concentrações (500,00 a 3,12mg/mL) onde foram mensurados os parâmetros: mortalidade das fêmeas (%), eclodibilidade dos ovos (%) e eficiência do produto (%). As larvas foram avaliadas pelo teste de imersão larval (Larval Packet Test) nas concentrações que variaram de 25,00 a 0,00004mg/mL. Foram determinadas as concentrações letais (CLs) necessárias para matar 50 e 99,9% das fêmeas adultas e das larvas utilizando a análise de Probitos. As CL50 e CL99,9 do OE foram (0,06 e 24,60mg/mL) para as larvas e (1.208,80 e 2.538mg/mL) para as fêmeas adultas, respectivamente. Outro parâmetro avaliado em nossa pesquisa foi mensurar a ação do OE no ciclo de vida livre das larvas de R.(B.) microplus; onde as larvas foram depositadas em vasos com Brachiaria decumbens e após migração destas para o ápice das folhas, foi aspergido solução contendo a CL99,9 (24,60mg/mL) do OE. Após 24 horas, 72,25% das larvas morreram indicando que houve estabilidade do OE quando submetido a condições de temperatura e umidade não controladas. O mecanismo de ação pelo qual o OE matou as larvas e fêmeas adultas foi investigado pelo método bioautográfico, indicando uma inibição de 3,15mg/mL do óleo essencial sobre a enzima acetilcolinesterase (AChE). Os resultados encontrados no presente experimento indicaram que o óleo essencial de E. pyriformis é uma alternativa no controle do carrapato bovino no estágio larval (parasitário) e no ciclo de vida livre (estágio não parasitário) em condições de campo.(AU)

Wild chive oil is an extremely effective larvicide against malaria mosquito vector Anopheles stephensi

Objective: To assess the chemical composition and mosquito larvicidal potentials of essential oil of wild chive (Allium schoenoprasum L.) against Anopheles stephensi. Methods: In the search for an environmentally safer alternative mosquitoes control, the larvicidal efficacy of essential oil obtained from the leaves of Allium schoenoprasum L. against Anopheles stephensi was determined. The composition of chive essential oil was analyzed by gas chromatography-mass spectrometry. Results: In toxicity assays, the essential oil demonstrated substantial larvicidal activity against larvae of Anopheles stephensi with LC

Evaluation of phytochemical properties and larvicidal activities of Cynodon dactylon, Clerodendrum viscosum, Spilanthes acmella and Terminalia chebula against Aedes aegypti

Objective: To investigate the phytochemical, antioxidant and larvicidal property of Cynodon dactylon, Clerodendrum viscosum, Spilanthes acmella and Terminalia chebula against Aedes aegypti. Methods: Antioxidant capacity of methanolic extract of the plants was studied by 2,2- Diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay, ferric reducing antioxidant power assay, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) assay (ABTS), thiobarbituric acid reactive substance (TBARS) assay, superoxide anion scavenging activity and total antioxidant activity assay following standard protocol. Total phenolic content, total flavonoid content, carbohydrate, and plant protein were also estimated following standard protocols. Larvicidal property of plant extracts were determined following World Health Organization standard protocol. Additionally, glutathione-s-transferase (GST) and acetylcholinesterase (AchE) inhibitory property was also tested biochemically. Results: Phytochemically, high protein, carbohydrate and phenolic were found in Terminalia chebula, while Cynodon dactylon showed high flavonoid contents. Similarly, high antioxidant activity was found in Terminalia chebula with IC

Wild chive oil is an extremely effective larvicide against malaria mosquito vector Anopheles stephensi

Objective: To assess the chemical composition and mosquito larvicidal potentials of essential oil of wild chive (Allium schoenoprasum L.) against Anopheles stephensi. Methods: In the search for an environmentally safer alternative mosquitoes control, the larvicidal efficacy of essential oil obtained from the leaves of Allium schoenoprasum L. against Anopheles stephensi was determined. The composition of chive essential oil was analyzed by gas chromatography-mass spectrometry. Results: In toxicity assays, the essential oil demonstrated substantial larvicidal activity against larvae of Anopheles stephensi with LC50 and LC90 values of 2.60, and 7.31 ppm after 24 h of exposure, respectively. Gas chromatography-mass spectrometry analysis of chive essential oil identified 35 components representing more than 97.31% of the total essential oil. The main constituents were sulfur compounds, including diallyl trisulfide (13.72%), 2-ethyl[1,3]dithiane (8.93%), allyl methyl trisulfide (8.77%), and trimethylene trisulfide (6.64%), respectively. Conclusions: This study demonstrated that wild chive essential oil has a rich source of eco-friendly bioactive compounds for use as a mosquito larvicide. The main reason for its extraordinary properties may be related to the high percentage of sulfur compounds.

Evaluation of phytochemical properties and larvicidal activities of Cynodon dactylon, Clerodendrum viscosum, Spilanthes acmella and Terminalia chebula against Aedes aegypti

Objective: To investigate the phytochemical, antioxidant and larvicidal property of Cynodon dactylon, Clerodendrum viscosum, Spilanthes acmella and Terminalia chebula against Aedes aegypti. Methods: Antioxidant capacity of methanolic extract of the plants was studied by 2,2- Diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay, ferric reducing antioxidant power assay, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) assay (ABTS), thiobarbituric acid reactive substance (TBARS) assay, superoxide anion scavenging activity and total antioxidant activity assay following standard protocol. Total phenolic content, total flavonoid content, carbohydrate, and plant protein were also estimated following standard protocols. Larvicidal property of plant extracts were determined following World Health Organization standard protocol. Additionally, glutathione-s-transferase (GST) and acetylcholinesterase (AchE) inhibitory property was also tested biochemically. Results: Phytochemically, high protein, carbohydrate and phenolic were found in Terminalia chebula, while Cynodon dactylon showed high flavonoid contents. Similarly, high antioxidant activity was found in Terminalia chebula with IC50 values at 13.7, 2.9, 45.2 and 46.0 μg/mL in DPPH, ABTS, TBARS and superoxide anion scavenging activity, respectively. Larvicidal study showed strongest activity in Spilanthes acmella followed by Cynodon dactylon, and Clerodendrum viscosum and Terminalia chebula. GST and AchE of Aedes aegypti larvae showed reduced enzyme activity when pre-incubated with Cynadon dactylon and Spilanthes acmella. Conclusions: The methanolic crude extracts of Cynodon dactylon, Clerodendrum viscosum, Spilanthes acmella and Terminalia chebula possess strong antioxidant and larvicidal property against Aedes aegypti and therefore, may be further investigated for the molecular mode of action.

Nanosuspension of quercetin: preparation, characterization and effects against Aedes aegypti larvae

Abstract Aedes aegypti (Diptera: Culicidae) is the main vector of some neglected diseases, including dengue. It is very important to develop formulations that increase effectiveness of vector control with low toxicity. Quercetin is a plant-derived flavonoid that modulates the development of some insects. The low water solubility of quercetin impairs the development of water-dispersible commercial products. To circumvent this problem, the preparation of nanoformulations is considered promising. Thus, this study aimed to evaluate the effect of bulk and quercetin nanosuspension against A. aegypti larvae and also to investigate their ecotoxicity. Quercetin nanosuspension was produced by a solvent displacement method followed by solvent evaporation and was maintained in two different temperatures (4 and 25 ºC). Its size distribution and zeta potential were monitored along 30 days. The influence of quercetin nanosuspension and bulk-quercetin was investigated at various concentrations against A. aegypti and the green algae Chlorella vulgaris. The quercetin nanosuspension presented higher stability at 4 ºC and negative zeta potential values. Quercetin nanosuspension and bulk-quercetin adversely affected the larvae development, especially at the highest concentrations. Larvae mortality was between 44% and 100% (48 h) for quercetin nanosuspension at 100 and 500 ppm, respectively. The bulk-quercetin induced around 50% mortality regardless the concentration used at this same time-period. Absence of emerging mosquitoes from water was observed on the survival larvae of all the treated groups. Quercetin nanosuspension was less toxic than bulk-quercetin against C. vulgaris, especially at higher concentrations. These data indicate that quercetin nanosuspension may represent a potential larvicide for A. aegypti control, once they induced larvae death and inhibited the survival ones to emerge from water. In addition, it did not demonstrated ecotoxicity against a non-target organism, highlighting its better properties, when compared to the bulk-quercetin.

Ginger oil (Zingiber officinale) in the fight against larvae of Contracaecum sp. that cause human zoonoses / Óleo de gengibre (Zingiber officinale) no combate a larvas de Contracaecum sp. causadoras de zoonoses humanas

Anisakid nematode helminths have great importance in public health, with several reports of human infections causedby larvae of these parasites in several countries of the world. These parasites are common in freshwater and marine fish,with man as an accidental host. Contamination occurs when humans feed on raw fish in the form of sushi, sashimi, andceviche, which are infected by the larval stages of these nematodes. In Brazilian rivers there are records of these larvaein Astyanax altiparanae (lambaris) and Geophagus brasiliensis (pearl cichlid), which are species widely distributed in theNeotropical region, especially in Brazil. These diseases are little-known by Brazilian health professionals because theirfrequency is still low, mainly due to the population's low fish consumption and the difficulties medical professionals havein diagnosing them. The present study aimed to evaluate the larvicidal action of ginger essential oil (Zingiber officinale) onlarvae of Contracaecum sp. removed from the visceral cavity of pearl cichlid and lambaris collected from the lake at IngáPark, Maringá, PR, in the year 2016. Two hundred and thirty-four fish specimens were necropsied, and their larvae weretested to verify the larvicidal effect of ginger. Of these fish, 123 were parasitized, equivalent to 52.5%, of which 181 larvaewere collected, all from the coelomic cavity. Ginger essential oil proved to be a promising larvicide, promoting larvaldeath in vitro. This larvicidal action was observed at different times and concentrations, showing the efficacy of ginger oilin combating this zoonosis. It is suggested that new natural products be tested for this purpose, as the number of peoplewho consume raw fish in Brazil continues to increase

Os helmintos nematoides anisaquídeos possuem grande importância em saúde pública, havendo vários relatos deinfecções humanas causadas pelas larvas desses parasitos em vários países do mundo. Esses parasitas são comuns empeixes de água doce e marinhos, tendo o homem como hospedeiro acidental. A contaminação ocorre quando os sereshumanos se alimentam de peixes crus na forma de sushi, sashimi e ceviche, infectados pelos estados larvais dessesnematoides. Nos rios brasileiros há registros dessas larvas em Astyanax altiparanae (lambaris) e Geophagus brasiliensis(acará ou papa-terra), que são espécies amplamente distribuídas na região Neotropical, em especial no Brasil. Essasdoenças são pouco conhecidas pelos profissionais da saúde brasileiros, pois sua frequência ainda é pequena, devido aobaixo consumo de peixes pela população e às dificuldades no diagnóstico pela classe médica. O presente estudo tevecomo objetivo avaliar a ação larvicida do óleo essencial de gengibre (Zingiber officinale) em larvas de Contracaecumsp. retirados da cavidade visceral de acarás e lambaris, coletados no lago do Parque do Ingá, Maringá, PR no ano de2016. Nesse sentido, 234 espécimes de peixes foram necropsiados e suas larvas testadas para verificar o efeito larvicidado gengibre. Destes peixes, 123 estavam parasitados, equivalendo a 52,5%, dos quais coletou-se 181 larvas, todas nacavidade celomática. Essas substancias mostraram-se promissores larvicidas, promovendo a morte das larvas no teste invitro do óleo essencial do gengibre. Essa ação larvicida foi observada em tempos e concentrações diferentes, mostrandoa eficácia do óleo de gengibre no combate a essa zoonose. Sugere-se que novos produtos naturais sejam testados comesse objetivo, pois é crescente o aumento no número de pessoas que passaram a se alimentar de peixes crus no Brasil

Larvicidal, pupicidal and oviposition deterrent activities of essential oils from Umbelliferae plants against house fly Musca domestica

Objective:To evaluate the toxicity against house fly Musca domestica L. (M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils (EOs) from five plants: Anethum graveolens L. (A. graveolens), Centratherum anthelminticum L. (C. anthelminticum), Foeniculum vulgare Mill. (F. vulgare), Pimpinella anisum L. (P. anisum), and Trachyspermum ammi L. (T. ammi) Sprague.Methods:Dipping, topical and dual-choice assays were performed by using each EO at three concentrations (1%, 5% and 10%) as well as cypermethrin (positive control) and ethyl alcohol (negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay.Results:All EOs at the highest concentration (10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of -1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LCConclusions:These results indicate that F. vulgare, A. graveolens and T. ammi EOs are effective larvicidal, pupicidal and oviposition deterrent agents against house fly M. domestica.

Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito,Aedes aegypti Linn. (Diptera: Culicidae)

Objective: To evaluate larvicidal, pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga (L.) Willd rhizome, Anethum graveolens L. (An. graveolens)fruit, Foeniculum vulgare Mill. fruit, and Pimpinella anisum L. fruit against Aedes aegypti (Ae. aegypti). Methods: Four essential oils at 1％, 5％ and 10％ concentrations were assessed for insecticidal activity against larvae and pupae of Ae. aegypti, following the procedure of a dipping method assay. Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae. aegypti by a dual-choice oviposition bioassay. Results: The results revealed that An. graveolens oil provided the strongest larvicidal activity against Ae. aegypti among four tested plant essential oils with the highest mortality rate of 100％ and LC50 value of -0.3％. From the pupicidal experiment, An. graveolens also showed the highest toxicity against Ae. aegypti pupae with the highest mortality rate of 100％ at 72 h and LC50 value of 2.9％. In addition, 10％ An. graveolens had an oviposition deterrent effect against Ae. aegypti with effective repellency of 100％ and an oviposition activity index of –1.0. Conclusions: An. graveolens oil has a good potential as a larvicidal, pupicidal and oviposition deterrent agent for controlling Ae. aegypti.

Larvicidal, pupicidal and oviposition deterrent activities of essential oils from Umbelliferae plants against house fly Musca domestica

Objective: To evaluate the toxicity against house fly Musca domestica L. (M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils (EOs) from five plants: Anethum graveolens L. (A. graveolens), Centratherum anthelminticum L. (C. anthelminticum), Foeniculum vulgare Mill. (F. vulgare), Pimpinella anisum L. (P. anisum), and Trachyspermum ammi L. (T. ammi) Sprague. Methods: Dipping, topical and dual-choice assays were performed by using each EO at three concentrations (1%, 5% and 10%) as well as cypermethrin (positive control) and ethyl alcohol (negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay. Results: All EOs at the highest concentration (10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of -1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LC

A potent larvicidal agent against Aedes aegypti mosquito from cardanol

ABSTRACT Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.