Instar Larvae Of Aedes Aegypti Research Articles

Eco-friendly synthesis of silver nanoparticles and its larvicidal property against fourth instar larvae of Aedes aegypti.

In this study, larvicidal activity of silver nanoparticles (AgNPs) synthesised using apple extract against fourth instar larvae of Aedes aegypti was determined. As a result, the AgNPs showed moderate larvicidal effects against Ae. aegypti larvae (LC50 = 15.76 ppm and LC90 = 27.7 ppm). In addition, comparison of larvicidal activity performance of AgNPs at high concentration prepared using two different methods showed that Ae. aegypti larvae was fully eliminated within the duration of 2.5 h. From X-ray diffraction, the AgNP crystallites were found to exhibit face centred cubic structure. The average size of these AgNPs as estimated by particle size distribution was in the range of 50-120 nm. The absorption maxima of the synthesised Ag showed characteristic Ag surface plasmon resonance peak. This green synthesis provides an economic, eco-friendly and clean synthesis route to Ag.

Magnesium incorporated hydroxyapatite nanoparticles: Preparation, characterization, antibacterial and larvicidal activity

Mosquito-borne diseases cause several deaths every year in tropical and subtropical climate countries. Control of vectors is an alarming problem in today’s world due to the resistance matters. In this study magnesium incorporated hydroxyapatite nanoparticles have been synthesized by microwave irradiation method. Magnesium chloride hexahydrate (MgCl2·6H2O) calcium nitrate tetra hydrate (Ca (NO3)2·6H2O) and disodium hydrogen phosphate (Na2HPO4) were used as magnesium, calcium and phosphorous sources to prepare hydroxyapatite nanoparticles. The FT-IR studies show the presence of hydroxyl and phosphate functional groups. The structural properties have been studied using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (HRTEM). The energy dispersive X-ray analysis (EDAX) revealed the presence of Ca, Mg, P and O in the prepared samples. The antibacterial activity of the as-synthesized nanoparticles was evaluated against two prokaryotic strains, the gram negative bacteria Escherichia coli for three different concentrations of as-synthesized nanoparticles and they showed excellent antibacterial activity. The as-synthesized Mg-HAp nanoparticles were tested against fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus and the nanoparticles exhibited significant mortality against the selected mosquitoes. The observed results suggest that the magnesium incorporated hydroxyapatite nanoparticles have the potential to be used as an effective mosquito larvae control agent against Ae. aegypti, An. stephensi, and Cx. quinquefasciatus. From the detailed literature review it has been observed that no work has been carried out so far on the larvicidal activity using hydroxyapatite (HAp) nanoparticles and magnesium substituted hydroxyapatite (Mg-HAp) nanoparticles.

Larvicidal Activity of A Mixture of Cashew Nut Shell Liquid and Water-Soluble Extract of Soap Nut Fruit (Sapindus rarak DC.) Against 3rd Instar Larvae of Aedes aegypti

<p>Cashew Nut Shell Liquid (CNSL) which has been known as a waste of processing cashew fruits which is contain phenolic compounds have activity as larvicides. Cashew nut shell liquid is not soluble in the water where the larvae grow. Cashew nut shell liquid mixed with water-soluble extract of soapnut fruit which serves as a natural surfactant that can emulsify oil in water. The test subjects were larvae of <em>Aedes aegypti </em>third instar. Test subjects were divided into treatment group and control group. In the treatment group, test subjects were the mixture of CNSL and Ethylacetat Soluble Extract (ESE) in tap water. The Larvae mortality observations were done 24 hours after the treatment. LC<sub>50</sub> and LC<sub>90 </sub>as final test data were analyzed using probit analysis. Extract constituents of CNSL and Water Soluble Extract of SoapNut fruit (WSEoSN) were investigated using Thin Layer Chromatography (TLC) method. The effect of CNSL as larvicides against third instar larvae of <em>Ae. aegypti </em>with were LC<sub>50</sub> of 14,12 ppm, while the LC<sub>90</sub> of 24,85 ppm.</p>

Bioassay guided isolation of mosquito larvicidal compound from acetone leaf extract of Elaeagnus indica Servett Bull and its in-silico study

The present study reports first-time for the isolation of pure mosquito larvicidal compound from Elaeagnus indica (Elaeagnaceae). Crude acetone leaf extract of E. indica was subjected to isolation of larvicidal principle through bioassay guided method using chromatography techniques. Based on the spectral analysis (UV, FT-IR, LC-MS, CHNS analysis, 1H, 13C, DEPT, HSQC and HMBC-NMR) the isolated compound was identified as (−)-α-thujone. The Larvicidal potential of isolated thujone was assessed against 4th instar larvae of Aedes aegypti (LC50=4.23mg/L) and Anopheles stephensi (LC50=3.30mg/L). In silico molecular docking study results reflects thujone show good interactions with Aedes aegypti Sterol Carrier Protein-2 with significant docking score (–8.2693) and Glide energy (–42.44kcal/mol). The present study demonstrates that isolated thujone from the leaf acetone extract of E. indica possesses remarkable mosquito larvicidal potential and strong interactions with AeSCP-2.

Evaluation of silver nanoparticles toxicity of Arachis hypogaea peel extracts and its larvicidal activity against malaria and dengue vectors.

Silver nanoparticles (AgNPs) were successfully synthesised from aqueous silver nitrate using the extracts of Arachis hypogaea peels. The synthesised SNPs were characterized by Fourier transform-infrared spectroscopy analysis, X-ray diffraction, transmission electron microscopy analysis and high-resonance scanning electron microscopy, and energy dispersive X-ray spectroscopy. AgNPs were well defined and measured 20 to 50 nm in size. The nanoparticles were crystallized with a face-centered cubic structure. Larvicidal activity of synthesised AgNPs from A. hypogaea peels was tested for their larvicidal activity against the fourth instar larvae of Aedes aegypti (Yellow fever), Anopheles stephensi (Human malaria). The results suggest that the synthesised AgNPs have the potential to be used as an ideal eco-friendly resource for the control of A. aegypti and A. stephensi. This study provides the first report on the mosquito larvicidal activity of synthesised AgNPs from A. hypogaea peels against vectors of malaria and dengue.

Phytochemical profile and larvicidal properties of seed essential oil from Nigella sativa L. (Ranunculaceae), against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

The present study deals with investigation of larvicidal activity and their chemical constituents of the essential oil from the seeds of Nigella sativa L. (Ranunculaceae). Totally, 18 chemical compounds were identified by GC and GC-MS analysis. Thymol (19.13 %) and α-phellandrene (14.9 %) were identified as major chemical components followed by camphor (12.14 %), borneol (11.31 %), and carvacrol (8.65 %). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that the essential oil were evaluated against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC50 = 196.9 and LC90 = 523.5 ppm (A. aegypti), LC50 = 88.1 and LC90 = 272.4 ppm (A.stephensi), and LC50 = 241.6 and LC90 = 545.4 ppm (C. quinquefasciatus), and the larvicidal activities after 24 h of exposure period were LC50 = 99.9 and LC90 = 300.8 ppm (A. aegypti), LC50 = 53.9 and LC90 = 172.6 ppm (A. stephensi), and LC50 = 141.7 and LC90 = 364.0 ppm (C. quinquefasciatus). The results of the present study showed that the essential oil from seeds of N. sativa is inexpensive food formulation and new source of natural larvicidal agent.

Larvicidal activity of a novel isoquinoline type pigment from Fusarium moniliforme KUMBF1201 against Aedes aegypti and Anopheles stephensi

The aim of this study is to isolate a novel fungal pigment from Fusarium moniliforme, so F. moniliforme KUMBF1201 a soil isolate from paddy field has been selected in this study. A new 2-(4-((3E,5E)-14-aminotetradeca-3,5-dienyloxy)butyl)-1,2,3,4-tetrahydroisoquinolin-4-ol (ATDBTHIQN) compound was isolated and characterized from the ethyl acetate extract of a fungal strain F. moniliforme KUMBF1201. The structure of ATDBTHIQN compound was established by detailed spectroscopic analysis by UV, FTIR, MS and NMR. This compound exhibited potent mosquito larvicidal activity against third and fourth instar larvae of Aedes aegypti (LC50=237.0 and 276.4ppm, r2=0.972 and 0.975) and Anopheles stephensi (LC50=335.6 and 258.1ppm, r2=0.987 and 0.977). The outcome suggests that the use of F. moniliforme KUMBF1201 can be rapid, environment friendly mosquito larvicides, which can form a novel approach to development of effective biolarvicides for controlling the target vector.

MORINGA OLEIFERA AND ANNONA MURICATA SEED OIL EXTRACTS AS BIOPESTICIDES AGAINST THE SECOND AND FOURTH LARVAL INSTAR OF AEDES AEGYPTI L. (DIPTERA: CULICIDAE)

Laboratory bioassay was conducted on the 2nd and 4th instar larvae of Aedes aegypti (Diptera:Culicidae) to investigate the efficacy of Moringa oleifera seed oil (MOSO) and Annona muricata seed oil (AMSO) (200, 100, 50, 25, 12.5 and 6.25 µL/mL) along with a control. Inhibition of emergence (IE) and larval mortality were monitored at 3-hours intervals for a period of 24 hrs. Results showed that MOSO at the highest concentration caused 94% and 70% mortality for both 2nd and 4th instar larvae respectively while AMSO gave 100% for both 2nd and 4th instar larvae. The level of IE was 100% for both toxicants after post-exposure culture for 10 days. Nevertheless, the 2nd instar larvae were more susceptible than the 4th instar. The LD50 values against the 2nd and 4th instar larvae were 18.19 µL/mL and 54.50 µL/mL for MOSO while AMSO were 9.49 µL/mL and 16.11 µL/mL respectively. AMSO was found to be more effective about twice at all stages than MOSO, therefore both oils show promise as biopesticides against Ae. aegypti mosquito larvae although further evaluations need to be carried out especially on the other mosquito genera and species.

Effects of the P20 protein from Bacillus thuringiensis israelensis on insecticidal crystal protein Cry4Ba

The accessory protein P20 from Bacillus thuringiensis israelensis has been defined as an important molecular chaperone for forming crystal Cyt1Aa, and enhancing Cry11Aa and Cry4Aa expression. To investigate its putative role in Cry4Ba delta-endotoxin production and toxicity, a p20 gene was cloned and introduced into B. thuringiensis recombinant strain expressing cry4Ba type gene (cry4BLB). The delta-endotoxin synthesis was enhanced by 262%. The generated inclusions were assayed against third instar larvae of Aedes aegypti. The combination of P20 protein with Cry4BLB delta-endotoxin led to a stable mortality rate of 25% with doses ranging from 0.2mgl−1 to 0.6mgl−1. Cry4BLB crystals produced in the presence of P20 were much less soluble than those produced by the control strain lacking P20 at pH lower than or equal to 10.5. The observed toxicity perturbation correlates with a decrease of Cry4BLB inclusions solubility. The presence of P20 protein has affected Cry4BLB crystallization and altered greatly its solubility properties. Cry4Ba effectiveness against A. aegypti larvae is related to the solubilization step in larval guts environment.

Extract of Bowdichia virgilioides and maackiain as larvicidal agent against Aedes aegypti mosquito

The larvicidal activities of extracts of three hardwood species (Hymenaea stigonorcapa, Anadenanthera colubrina and Bowdichia virgilioides) against 4th instar larvae of Aedes aegypti were evaluated using WHO guidelines. Extracts of H. stignocarpa and A. colubrina showed weak activity. The highest larvicidal effect was obtained with the cyclohexane extract of the heartwood of B. virgilioides, which caused 100% mortality at concentrations at 50 and 100 µg/mL. Fraction toluene/EtOAc (8:2) from this extract showed larvicidal activity (LC50 = 34.90 ± 1.27 µg/mL). A mixture of two compounds identified as medicarpin and maackiain exhibited a very good larvicidal activity (sub-fraction 2, LC50 = 17.5 ± 1.87 µg/mL) and maackiain showed to be a strong larvicidal compound (LC50 = 21.95 ± 1.34 µg/mL). This result can be of value in the search for new natural larvicidal compounds from other hardwood plant extracts and presents the first report of B. virgilioides being used to control a mosquito vector.

Unique biochemical and molecular biological mechanism of synergistic actions of formamidine compounds on selected pyrethroid and neonicotinoid insecticides on the fourth instar larvae of Aedes aegypti (Diptera: Culicidae)

We recently reported that formamidine pesticides such as amitraz and chlordimeform effectively synergize toxic actions of certain pyrethroid and neonicotinoid insecticides in some insect species on the 4th instar larvae of Aedes aegypti. Here we studied the biochemical basis of the synergistic actions of the formamidines in amplifying the toxicity of neonicotinoids and pyrethroids such as dinotefuran and thiamethoxam, as well as deltamethrin-fenvalerate type of pyrethroids. We tested the hypothesis that their synergistic actions are mediated by the octopamine receptor, and that the major consequence of octopamine receptor activation is induction of trehalase to increase glucose levels in the hemolymph. The results show that formamidines cause a significant up-regulation of the octopamine receptor and trehalase mRNA expressions. Furthermore, formamidines significantly elevate levels of free glucose when co-treated with dinotefuran, deltamethrin and fenvalerate, but not with permethrin or fenitrothion, which showed no synergistic toxic effects with formamidines. These results support the conclusion that the main mode of synergism is based on the ability to activate the octopamine receptor, which is particularly effective with insecticides causing hyperexcitation-induced glucose release and consequently leading to quick energy exhaustion.

Identification of Metarhizium strains highly efficacious against Aedes, Anopheles and Culex larvae

Entomopathogenic fungi, such as Metarhizium anisopliae and Beauveria bassiana, have been shown to be efficacious in killing mosquito larvae of different mosquito species. The current study compared the pathogenicity and efficacy of two formulations of three fungal strains against different instars of three mosquito species with the aim of identifying the most virulent strain for use under field conditions. Three strains of Metarhizium, ARESF 4556, ARSEF 3297 and V275, were assayed against early (L2−3) and late (L3–4) instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Two formulations of the fungi were tested, dry conidia and aqueous suspensions (i.e. ‘wet’ conidia). Effects of all combinations of conidia, mosquito species, instar, fungal strain and concentration on mosquito mortality were analysed using Cox regression and Kaplan–Meier analyses. Strain ARSEF 4556 was more virulent than ARSEF 3297 and V275, with LT50 values ranging from 0.3 to 1.1 days, with Anopheles and Culex being more susceptible than Aedes. Early and late instars were equally susceptible independent of species. Although the formulation did influence mortality rates, both ‘wet’ and ‘dry’ conidia applications were highly effective in killing mosquito larvae. Viable spores were more efficacious than heat killed spores. The latter did cause mortality but only at high concentrations. Metarhizium sp. has proved to be effective in reducing survivability of all larval stages of Aedes, Anopheles and Culex under laboratory conditions. Aedes larvae were generally more tolerant than Anopheles and Culex irrespective of fungal strain.

Larvicidal activity of <i>Murraya koenigii</i> (L.) Spreng (Rutaceae) hexane leaf extract isolated fractions against <i>Aedes aegypti</i> Linnaeus, <i>Anopheles stephensi</i> Liston and <i>Culex quinquefasciatus</i> Say (Diptera: Culicidae)

Mosquitoes are significant public health pests and act as a vector of several diseases viz ., malaria, filariasis, Japanese encephalitis, dengue fever and chikungunya, which are transmitted by the three genera of mosquitoes, viz ., Anopheles, Culex and Aedes . Mosquito control strategies have depended primarily on the use of synthetic chemical insecticides but resulted in rebounding vectorial capacity, environmental and human health concerns. Plants may be a source of alternative agents to replace the synthetic insecticides for mosquito control. In the present study, the isolated fractions of Murraya koenigii hexane leaf extracts were evaluated for larvicidal activity against vector mosquitoes viz., Aedes aegypti , Anopheles stephensi and Culex quinquefasciatus . Six fractions viz., A, B, C, D, E and F were obtained from the residue of hexane extract by column chromatography. Standard WHO protocol with minor modifications was adopted for the larvicidal bioassay. Larvicidal activity was evaluated against the isolated fractions at concentrations of 25, 50, 75 and 100 ppm. Larval mortality was observed 24 hours post exposure. Amongst the isolated fractions tested, fraction ‘D’ showed 100.0, 97.6 and 99.2% mortality against third instar larvae of Aedes aegypti , Culex quinquefasciatus and Anopheles stephensi at 100 ppm, respectively and LC50 values were 35.06, 27.20 and 42.51 ppm respectively. Further investigations are needed to explore the larvicidal activity of the isolated fraction ‘D’ of hexane leaf extract of this plant and also the active principle(s) responsible for larvicidal activity.

New Bioinsecticide Granules Toxin from Ectract of Papaya (Carica Papaya) Seed and Leaf Modified Against Aedes Aegypti Larvae

The epidemic of dengue hemorrhagic fever (DBD) in Indonesia, which occurs every year, has become a problem for the Indonesian society. Aedes aegypti mosquito is a vector of this disease. During this time the larvae of Aedes aegypti only has one exterminator is abate. In the long time exposure of single type insecticide will cause resistance. Therefore, it is necessary to find new bioinsectiside which is expected to have effects such as abate. The aims of this study are to offer technology, dosage, formulation and toxicity of new bioinsecticide granules toxin from ectract of papaya (Carica papaya) seed and leaf modified against Aedes aegypti larvae. Methodpreparation of the extract by percolation method with 70% ethanol for seeds, and with water-ethanol 70% for leaf. Bioassay with active ingredients with thin layer chromatography. Formulation for 300g Granules are: active substances papaya seed and leaf modified: 90%, seed flour 5%, filler: 5%. This was an experiment using a completely randomized design with 6 treatment groups. Each group contained 20 third instar larvae of Aedes aegypti. Concentrations of granules are 0, 30, 60, 90. 120, 150ppm, with Temephos 1% as a positive control. Data was analyzed using Probit analysis. ResultsThe result of phytochemical analysis contains secondary metabolites compounds of saponin, flavonoid and triterpenoid. Toxicity (LC50) in this study is reported 107ppm; 48hours and LC90: 150ppm, 48hours. ConclusionNew Bioinsecticide Granules Toxin from extract of Papaya (Carica papaya) Seed and leaf Modified Against Aedes aegypti larvae possess technology, dosage, formulation, and larvicidal remarkable. Further investigations are needed to elucidate active ingredient responsible for larvacidal activity should be identified and utilized in preparing a commercial product.

Green Synthesis of Silver Nanoparticles from Ocimum sanctum against Mosquito Vectors for Malaria and Dengue

Vector-borne diseases such as malaria, filariasis, yellow fever, dengue, and Japanese encephalitis are major illnesses in in tropical countries. The main objective of this study was to investigate the larvicidal activity of synthesized silver nanoparticles (AgNPs) utilizing aqueous leaf extract of Ocimum sanctum against fourth instar larvae of Aedes aegypti and Anopheles stephensi. The present study was carried out to establish the larvicidal activity of synthesized silver nanoparticles (AgNPs) using leaf aqueous extract of Ocimum sanctum against fourth instar larvae of dengue and malaria vector. The larval mortality was observed after different time of exposures. Further, characterization such as XRD and SEM analysis were carried out for the synthesized silver nanoparticles. The mortality values were obtained using the probit analysis. The larvae of Aedes aegypti and Anopheles stephensi were found to be highly susceptible for the silver nanoparticles. The larvae have shown 100% mortality against the silver nanoparticles, whereas fourth instar larvae have shown efficacy (LC50) after 24 and 48 hr. The characterization studies of synthesized AgNPs by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), of silver nanoparticles along with stability. In conclusions, the findings revealed that synthesized AgNPs possess excellent mosquito larvicidal activity. These results suggest that the green synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of head lice and vectors.

Relative Toxicity of Leaf Extracts of Eucalyptus globulus and Centella asiatica against Mosquito Vectors Aedes aegypti and Anopheles stephensi

The larvicidal activity of different solvent leaf extracts (hexane, diethyl ether, dichloromethane, and methanol) of Eucalyptus globulus and Centella asiatica against two geographically different strains of Aedes aegypti and Anopheles stephensi was investigated. The extracts were tested against the late third instar larvae of Aedes aegypti and Anopheles stephensi, and larval mortality was observed after 24 hours of treatment. LC50 and LC90 were calculated. The LC50 values of hexane extract of Eucalyptus globulus against the late third instar larvae of the BSN and JPN strains of Aedes aegypti and the DLC and KNG strains of Anopheles stephensi were 225.2, 167.7, 118.8, and 192.8 ppm, while those of the hexane extract of Centella asiatica were 246.5, 268.7, 50.6, and 243.5 ppm, respectively. The LC50 values of diethyl ether extract of Centella asiatica were 339.6, 134.5, 241, and 14.7 ppm. The hexane extracts of both plants and the diethyl ether extract of C. asiatica presented the highest potential for the control of Aedes aegypti and Anopheles stephensi. The present findings also reveal the necessity of assaying multiple strains of a species to fully comprehend the larvicidal efficacy of a compound.

Uji Efektivitas Ekstrak Daun Kemangi Hutan (Ocimum sanctum) Terhadap Kematian Larva Instar III Aedes aegypti

Dengue Haemorrhagic Fever (DHF) is a health problem, especially in countries that have tropical climates, including Indonesia. Eradication for Aedes aegypti as a vector of dengue disease can be did to the larvae by larviciding. One of the larviciding can be made by forest basil (Ocimum sanctum). This study aims to determine the most effective concentration of extract that kills the larvae in the third instar Aedes aegypti, knowing the value of LC50 and LC90, and then knowing the value of LT50 and LT90 of forest basil leaf extract (Ocimum sanctum). Research is using a completely randomized design with factorial, and the first factor is forest basil leaf extract with 5 level concentrations, there are 0,3%, 0,6%, 0,9%, 1,2%, 1,5%, and 0% as control, whereas the second factor is observation period that began after the death of the larvae. Observations were made up to 4320 minutes. The results showed that the influence of forest basil leaf extract against third instar larvae mortality of Aedes aegypti, and the most effective concentration of extract to kill the larvae was 1,5%. LC50 values of this study was 0,97%, and for the LC90 value was 1,42%. Value of LT50 and LT90 of this study is 342,31 and 1021,22 minutes. The conclusion of this study is basil leaf extract forest affect mortality third instar larvae of Aedes aegypti, and the most effective concentration of extract was 1,5%. Keywords: Forest basil (Ocimum sanctum), larvicides, larvae of Aedes aegypti

Larvicidal activity of Persea americana Mill. against Aedes aegypti

ObjectiveTo evaluate the toxicity of the ethanol and hexane extracts of the different parts of Persea americana Mill. (P. americana) toward third and fourth instars larvae of Aedes aegypti (Ae. aegypti) and to characterize the ethanol extract by qualitative phytochemical analysis. MethodsThe seeds, peels and pulp of P. americana were processed for crude extraction using 95% ethanol and n-hexane. Crude extracts were bio-assayed for larvicidal activity against Ae. aegypti following the World Health Organization standard bioassay method. The mortality was observed at 24 h and 48 h after treatment and data were subjected to probit analysis to determine lethal concentrations (LC50 and LC90). The ethanol extract was characterized by phytochemical analysis. ResultsBoth the hexane and ethanol extracts from the different parts of P. americana exhibited evidence of larvicidal toxicity. The hexane extract from the seeds exhibited the highest toxicity with LC50 and LC90 values of 9.82 mg/L and 22.19 mg/L, respectively, while the ethanol seed extract exhibited LC50 of 16.48 mg/L and LC90 45.77 mg/L, respectively. This was closely followed by the ethanol extract of the peels with an LC50 of 10.35 mg/L and LC90 of 26.29 mg/L. The pulp extracted with ethanol also yielded great larvicidal toxicity with LC50 of 21.32 mg/L and LC90 of 59.45 mg/L. Results of the phytochemical analysis of the ethanol seed extract indicated presence of alkaloids, tannins, saponins, unsaturated steroids and triterpenoids, flavonoids (leucoanthocyanins), fats and oils. ConclusionsBoth the hexane and ethanol extracts of P. americana showed promising potential as an alternative source of a more sustainable, non-toxic and environmentally friendly solution for the control of dengue vector, Ae. aegypti.

Mosquito larvicidal and silver nanoparticles synthesis potential of plant latex

Silver nanoparticles (AgNPs) were synthesized from the latex of the medicinally important plants <em>Euphorbia milii</em>, <em>Euphorbia hirta</em>, <em>Ficus</em> <em>racemosa</em> and <em>Jatropha</em> <em>curcas</em>. Synthesized AgNPs were characterized by UV-Vis spectrophotometry, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, Fourier transformed infrared spectroscopy, particle size, and zeta potential analysis. Potency of latex and latex-synthesized AgNPs was evaluated against the 2<sup>nd</sup> and 4<sup>th</sup> instar larvae of <em>Aedes</em> <em>aegypti</em> and <em>Anopheles stephensi</em>. The lowest lethal concentration 50 (LC<sub>50</sub>) value among the different types of plant latex studied was observed for latex of <em>E. milii</em> (281.28±23.30 and 178.97±37.82 ppm, respectively) against 2<sup>nd</sup> instar larvae of <em>Ae. aegypti</em> and <em>An. stephensi. E. milii</em> latex-synthesised AgNPs showed a high reduction in LC<sub>50</sub> compared with its latex; <em>i.e.</em>, 8.76±0.46 and 8.67±0.47 ppm, respectively, for 2<sup>nd</sup> instars of <em>Ae. aegypti</em> and <em>An. stephensi</em>. LC<sub>50</sub> values of AgNPs synthesized using the latex of <em>E. hirta</em>, <em>F. racemosa</em> and <em>J. curcas</em> were lower than those of the latex of the respective plants; <em>i.e.</em>, 10.77±0.53, 9.81±0.52, 12.06±0.60 and 8.79±0.51, 9.83±0.52, 9.60±0.51 ppm, respectively, for 2<sup>nd</sup> instars of <em>An. stephensi</em> and <em>Ae. aegypti</em>. Similarly, as compared with the plant latex, lower LC<sub>50</sub> values were reported for latex-synthesized AgNPs against 4<sup>th</sup> instars of <em>Ae. aegypt</em> and <em>An. stephensi.</em> Results showed that all the types of plant latex investigated have the potential to convert silver nitrate into AgNPs showing a spectrum of potent mosquito larvicidal effects, indicating the possibility of further exploration of the bioefficacy of latex and latex-synthesized AgNPs against vectors of public health concerns.

Elemental Analysis and Bioactivities of Ripe and Unripe Pericarp of <i>Polyalthia longifolia</i> (Annonaceae)

Polyalthia longifolia (Annonaceae) is an ornamental street tree having several medicinal values. The plant is used in traditional systems of medicine. The present study was conducted with an aim of estimating the content of minerals and determining bioactivities viz., antibacterial, cytotoxic and larvicidal activity of ripe and unripe pericarp of P. longifolia. The content of major and minor elements in powdered ripe and unripe pericarp was estimated by ICP-OES after microwave digestion using nitric acid. The pericarp powders were extracted using methanol and the extracts were subjected to preliminary phytochemical analysis. Antibacterial activity of pericarp extracts was determined against two Gram positive and three Gram negative bacteria by agar well diffusion assay. Cytotoxic potential of pericarp extracts was determined against two cell lines viz., HT-29 and MDA-MB-231 by MTT assay. Insecticidal activity, in terms of larvicidal activity of pericarp extracts was tested against II instar larvae of Aedes aegypti. The content of all elements except copper was highest in ripe pericarp. The content of potassium and iron was highest among major and minor elements respectively. Pericarp extracts caused dose dependent inhibition of test bacteria. Extract of ripe pericarp caused higher inhibition of test bacteria than extract of unripe pericarp. Both extracts showed concentration dependent cytotoxic effect. The cytotoxic effect of both the extract was pronounced against HT-29 than MDA-MB-231. The extracts exhibited dose dependent larvicidal effect. Among extracts, potent larvicidal activity was observed in case of ripe extract. Preliminary phytochemical analysis revealed the presence of flavonoids, tannins, saponins, steroids and glycosides in both the extracts. In conclusion, the ripe and unripe pericarp extracts of P. longifolia were found to contain various minerals in an appreciable quantity. The observed dose dependent bioactivities viz., antibacterial, cytotoxic and larvicidal activities might be ascribed to the presence of phytoconstituents. There is a great potential for the development of therapeutic agents from ripe and unripe pericarp. Further studies on isolation of active principles from pericarp extracts and their bioactivity determinations are under progress.Keywords: Polyalthia longifolia; Pericarp; Minerals; ICP-OES; Agar well diffusion; MTT;Larvicidal