Larvicidal Potential Research Articles

Exploiting the combination of entomopathogenic fungi and Illicium verum essential oil against Aedes aegypti larvae

Here, the effectiveness of Beauveria bassiana LCM S19 and Metarhizium anisopliae LCM S01, combined with Illicium verum essential oil (EO) against Aedes aegypti larvae was investigated. The EO compounds were first identified through gas chromatography, with the primary compound being (E)-anethole. Subsequently, in silico analysis was employed to predict the biological activity of (E)-anethole, revealing 89 molecular targets, which included insecticidal activity. Next the impact of EO on fungal viability and colony growth was examined and the EO had no effect on fungal development. Next, we investigated the influence of EO on fungal viability and colony growth, revealing that the EO had no discernible impact on fungal development. Following this, individual assessments were carried out to determine larval susceptibility to EO at concentrations of 40, 60, 80, and 100 ppm, as well as with both fungal isolates at conidial concentrations of 1 × 106, 1 × 107, and 1 × 108 conidia/mL. Larval survival was then monitored over a period of seven days. To further optimize the larvicidal potential, EO at a concentration of 40 ppm was combined with both isolates at a conidial concentration of 1 × 106 conidia/mL and tested against mosquito larvae, as described earlier. The combination of M. anisopliae and EO resulted in a substantial decrease, with only 20 % of larvae surviving over a seven-day period, in contrast to approximately 50 % survival observed in the pure M. anisopliae or EO treatments. B. bassiana, whether used alone or in combination with EO, exhibited a 50 % reduction in larval survival. The combination of M. anisopliae and EO exhibited a synergistic effect in targeting Ae. aegypti larvae, whereas B. bassiana, in conjunction with EO, had an additive effect. Notably, the combination achieved its impact in just 3 days, whereas the pure fungus required 7 days to yield similar results. These findings underscore the substantial potential of combining I. verum essential oil with both fungal isolates against Ae. aegypti larvae.

Bioactive components in Psidium guajava extracts elicit biotoxic attributes and distinct antioxidant enzyme modulation in the larvae of vectors of lymphatic filariasis and dengue

Control of mosquito vectors, which have caused a global disease burden, has employed various methods. However, the challenges posed by current physical and chemical methods have raised concerns about vector control programs, leading to the search for alternative methods that are less toxic, eco-friendly, and cost-effective. This study investigated the larvicidal potential of aqueous, methanol, and ethylacetate extracts of Guava (Psidium guajava) against Aedes aegypti and Culex quinquefasciatus larvae. Functional group and phytochemical characterization were performed using Fourier-Transform Infrared Spectroscopy (FTIR) and GC-MS analysis to identify the bioactive compounds in the extracts. Larval bioassays were conducted using WHO standard procedures at concentrations of 12.5, 25, 50, 125, and 250 mg/L, and mortality was recorded after 24, 48, and 72 h. Additionally, antioxidant enzyme profiles in the larvae were studied. All of the solvent extracts showed larvicidal activity, with the methanol extract exhibiting the highest mortality against Ae. aegypti and Cx. quinquefasciatus larvae, followed by aqueous and ethylacetate extracts. FTIR spectroscopic analysis revealed the presence of OH, C–H of methyl and methylene, CO and CC. The GC-MS analysis indicated that the methanol, aqueous, and ethylacetate extracts all had 27, 34, and 43 phytoactive compounds that were effective at causing larvicidal effects, respectively. Different concentrations of each extract significantly modulated the levels of superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione in larvae. This study's findings indicate the potential for developing environmentally friendly vector control products using the bioactive components of extracts from P. guajava leaves.

Efficacy of maturase K and rpL20 protein extracted from C. procera leaves on Anophelesstephensi

The present work is carried out to protein isolation, purification, and characterization from leaves, stem, and seed of C. procera and to evaluate the larvicidal potential on Anopheles stephensi. The whole protein was isolated using protein extraction buffer and precipitated by ammonium sulphate and larvicidal active protein was purified by the column chromatography. The homogeneity of larvicidal protein was confirmed by the SDS-PAGE. The identification of protein was done by the HPLC and LC-MS/ESI-MS.The crude protein from leaves showed 100% mortality of 3rd instar larvae of An. stephensi at the concentration of 5.5 mg/ml after 24 h of exposure. The crude protein from stem showed 25% mortality and no mortality observed was observed in seed protein. The leaves crude protein was further purified by ion exchange chromatography and eluted fractions were tested for larvicidal potential. The purified single protein fractions L2 and L3 from C. procera leaves showed 100% mortality at concentration of 0.06 mg/ml. The homogeneity of purified protein was confirmed by SDS-PAGE and two bands of 26 kDa and 15 kDa protein were observed. The peptide sequence “R.SQMLENSFLIENVMKR.L” was identified in the trypsin digested homogenous protein fraction L2 and “R.DRGSQKR.N” peptide sequence in L3 fraction by LC-MS/ESI-MS. The CprL2 peptide showed the sequence similarity with the protein maturase K and CprL3 peptide showed the sequence similarity with ribosomal protein L20 of C. procera. The conserved functional domain was also identified in both the CprL2 and CprL3 peptide. The identified proteins showed strong larvicidal efficacy at very low concentration. The identified proteins are novel and natural larvicidal agents against An. stephensi and hence can be used to control the malaria.

Therapeutic Potential of Dicentrine in Human Disorders: A Review On Medicinal Importance and Pharmacological Activities of Aporphine Alkaloid

Backgrounds: Plants have always been an important source of food and drugs, in addition to their application in medical and cosmetic sectors. The popularity of herbal remedies has increased in many countries in recent decades. Herbal medicines contain numerous active phytocomponents with different biological activities. Alkaloid class phytochemicals have diverse chemical structures and pharmacological activities in nature. Additionally, Aporphinoids are an important class of plant secondary metabolites that have been used for the treatment of numerous human disorders for a long time in traditional medicine. Dicentrine is an aporphine class phytochemical isolated from numerous medicinal plants, including Actinodaphne sesquipedalis and Lindera megaphylla. Methods: The biological potential of dicentrine, an aporphine alkaloid derivative, has been described in the present work. Scientific data on dicentrine were collected here from different scientific databases and presented in this paper in order to know the biological importance of dicentrine in medicine for the treatment of human complications. Further, detailed pharmacological activities and scientific data on dicentrine were also analyzed in order to determine its therapeutic potential in medicine. Moreover, its analytical aspects were also described in this work to understand its separation and isolation methods. Results: The present work described the biological potential of dicentrine in medicine and its analytical aspects. It signified the biological potential of dicentrine in cancer, breast cancer, oral squamous cell carcinoma, lung adenocarcinoma, blood pressure, inflammatory disorders, hyperlipidaemia, arrhythmia, stomach muscle, and glomerulonephropathy. Further, its effectiveness in medicine was found to be mainly because of its antiplatelet, alpha 1-adrenoceptor, epidermal growth factor, antiprotozoal, larvicidal, antimicrobial, topoisomerase II, and acetylcholinesterase inhibitory potential. Moreover, other scientific data also signified its metabolism and pharmacokinetic parameters in terms of its analytical aspects in medicine. Conclusion: The present review gives us an updated summary of the scientific information for pharmacological activities and analytical aspects of dicentrine in medicine. It also signified the potential contribution of dicentrine in medicine for the development of a newer class of drug molecules for human disorders.

Deciphering the therapeutic, larvicidal, and chemical pollutant degrading properties of leaves-mediated silver nanoparticles obtained from Alpinia purpurata

The aim of the study was to synthesize silver nanoparticles (AgNPs) from Alpinia purpurata leaves and evaluate their cytotoxic, antimicrobial, antibiofilm, dye degradation, and larvicidal potentials. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, Fourier transform infrared, and high-resolution transmission electron microscopy, which confirmed AgNPs synthesis and revealed nanoparticle size (10 to 30 nm) and the presence of silver. Cytotoxicity tests showed IC50 values of 4.59 ± 0.6 µg/mL in A549 cells and 3.48 ± 0.4 µg/mL in PA1 cells, inducing apoptosis and DNA fragmentation. Flow cytometry revealed cell cycle arrest at G0-G1 phase. AgNPs exhibited significant antimicrobial activity, with maximum inhibition zones against K. pneumoniae (23 ± 2 mm) and F. oxysporum (17 ± 2 mm), and minimum inhibitory concentration (MIC) values ranging from 12.5 ± 0.25 to 75 ± 2.5 µg/mL. They also reduced bacterial and fungal biomass and showed antibiofilm effects. Photocatalytic activity degraded methylene blue dye by 88.4 ± 1.4% in 60 minutes. Larvicidal activity resulted in 100% mortality of A. aegypti larvae after 48 hours exposure to AgNPs (10 mg/L), additionally reducing chemical oxygen demand (55.1 ± 2.1% to 63.8 ± 1.5%) and microbial load in wastewater (2.5 to 10 ppm).

Larvicidal and Ovicidal Properties of Essential Oils Derived from Origanum minutiflorum and Salvia dorystoechas against the Aedes aegypti

This study assessed the larvicidal and ovicidal effects of essential oils extracted from the above ground of Origanum minutiflorum and Salvia dorystoechas, belonging to the Lamiaceae plant family, on Aedes aegypti mosquito larvae and eggs. The research utilized essential oil concentrations ranging from 1 to 100 ppm. Larvicidal activity was evaluated 6 hours post-exposure and subsequently at 24-hour intervals over a period of 5 days while ovicidal activity was monitored every 2 days for a total of 10 days. Findings indicated that both essential oils demonstrated significant larvicidal effects at 50 and 100 ppm concentrations against Ae. aegypti larvae. In contrast, ovicidal effects were not observed to be statistically significant. Throughout the experiment, O. minutiflorum essential oil consistently showed higher larvicidal potency compared to S. dorystoechas. Therefore, while essential oils from both O. minutiflorum and S. dorystoechas effectively target Ae. aegypti larvae, especially at elevated concentrations, they did not exhibit ovicidal properties.

Elytrigia Repens Extracts Control Urban Mosquito Vectors with a Larvicidal Potential

There is over 17% of global illnesses due to Vector-borne diseases and more than a million fatalities annually found as a significant public health challenge globally. Traditional methods of mosquito control are relied heavily on chemical insecticides, and led to ecological disruptions, pesticide resistance, and adverse effects on human health and the environment. Consequently, there is a persistent need for alternative and eco-friendly strategies mosquito control. Method: In this study, we investigated the efficacy of extracts from Eragrostis repens (E. repens) against the larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Plant extracts were prepared using different solvents, and their phytochemical profiles were analyzed. The larvicidal activity of these extracts was evaluated through susceptibility tests over a 24-hour period. Results: Methanol extracts exhibited significant larvicidal activity against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, with LC50 values ranging from 43,173 ppm to 58,234 ppm. GC-MS analysis identified 11 bioactive compounds in methanol extracts, highlighting their potential insecticidal activity. Conclusion: Our findings suggest that E. repens holds promise as a natural larvicide against mosquito vectors. The study highlights the importance of exploring botanical alternatives for mosquito control, offering a sustainable and environmentally friendly approach to combatting mosquito-borne diseases.

Biological, biochemical and genotoxicological alterations of Benzylamine on Biomphalaria alexandrina snails and its Schistosoma mansoni larvicidal potential

Biomphalaria spp. snails are freshwater gastropods that responsible for Schistosoma mansoni transmission. Schistosomiasis is a chronic illness that occurred in underdeveloped regions with poor sanitation. The aim of the present study is to evaluate the molluscicidal activity of benzylamine against B. alexandrina snails and it larvicidal effects on the free larval stages of S. mansoni. Results showed that benzylamine has molluscicidal activity against adult B. alexandrina snails after 24 h of exposure with median lethal concentration (LC50) 85.7 mg/L. The present results indicated the exposure of B. alexandrina snails to LC10 or LC25 of benzylamine resulted in significant decreases in the survival, fecundity (eggs/snail/week) and reproductive rates, acetylcholinesterase, albumin, protein, uric acid and creatinine concentrations, levels of Testosterone (T) and 17β Estradiol (E), while alkaline phosphatase levels were significantly increased in comparison with control ones. The present results showed that the sub lethal concentration LC50 (85.7 mg/L) of benzylamine has miracidial and cercaricidal activities, where the Lethal Time (LT50) for miracidiae was 17.08 min while for cercariae was 30.6 min. Also, results showed that were decreased significantly after exposure to sub lethal concentrations compared with control. The present results showed that the expression level of NADH dehydrogenase subunit 1 (ND1) genes and cytochrome oxidase subunit I (COI) in B. alexandrina snails exposed to LC10 or LC25 concentrations benzylamine were significantly decreased compared to the control groups. Therefore, benzylamine could be used as effective molluscicide to control schistosomiasis.

Zinc oxide nanoparticles fabricated with phytoextracts for the control of mosquito vectors- A systemic Review

Transmission of pathogens by mosquito vectors pose serious challenges to public health. Controlling the vectors is a promising option in preventing the spread of infectious agents. Several chemical approaches though effectively control mosquitoes, proved to cause side effects including resistant mosquito species and environmental contamination. Green chemistry mediated nanoparticles synthesis is simple, quick, economically modest and environmentally safe and hence could be a safe alternative. The purpose of this review is to categorise, analyse, and organise the main findings from research papers on plant extract mediated zinc oxide nanoparticles (ZnO-NPs) with potential larvicidal properties. The investigation involved analysing the published literature from different scientific databases. The main focus was on identifying scientific reports on the green synthesized ZnO-NPs that showed the larvicidal potency (LC50) less than 25 μg/mL. Further, the review discusses the various methods of synthesis of ZnO-NPs and their mechanism of toxicity against mosquito larvae. The consolidated and organized information presented in this review can be effectively utilized for the design, development, and optimization of phyto-mediate nanoparticles synthesis with potential larvicidal activity. The summarized data provides a foundation for further research and application in the field of herbal insecticides, particularly focusing on their larvicidal properties.

Evaluation of larvicidal potential of Eritrean medicinal plants against Aedes aegypti.

Larvicidal activity of three Eritrean medicinal plants was evaluated against Aedes aegypti by conducting the bioassay using WHO methods. Efficacy of the plant extracts of O. hadiense, R. officinalis and C. spinarum was evaluated against 3rd instar Aedes aegypti larvae and mortality was recorded. LC50 and LC90 of the various plant extracts were also calculated using probit analysis. The morphological analysis of treated larvae was also performed. Extracts of O. hadiense, C. spinarium and R. officinalis were prepared using different solvents viz chloroform, 70% ethanol and water. Of the screened extracts, the chloroform extracts of O. hadiense exhibited the highest larvicidal activities and has the minimum LC50 and LC90 (24mg/ml and 198.411mg/ml respectively). Chloroform extract of C. spinarium exhibited the least larvicidal activity with maximum LC50 and LC90 (736.883mg/ml and 1188.699mg/ml respectively). Microscopic analysis confirmed the changes in the Aedes aegypti larvae caused by various plants extracts. An accumulation of dark pigmentation was observed in abdominal region and in the anal papillae after contact and also showed major structural damage such as destruction of the gut.

Chemical Composition of Piper nigrum L. Cultivar Guajarina Essential Oils and Their Biological Activity.

The essential oils and aroma derived from the leaves (L), stems (St), and spikes (s) of Piper nigrum L. cv. Guajarina were extracted; the essential oils were extracted using hydrodistillation (HD), and steam distillation (SD), and the aroma was obtained by simultaneous distillation and extraction (SDE). Chemical constituents were identified and quantified using GC/MS and GC-FID. Preliminary biological activity was assessed by determining the toxicity against Artemia salina Leach larvae, calculating mortality rates, and determining lethal concentration values (LC50). The predominant compounds in essential oil samples included α-pinene (0-5.6%), β-pinene (0-22.7%), limonene (0-19.3%), 35 linalool (0-5.3%), δ-elemene (0-10.1%), β-caryophyllene (0.5-21.9%), γ-elemene (7.5-33.9%), and curzerene (6.9-31.7%). Multivariate analysis, employing principal component analysis (PCA) and hierarchical cluster analysis (HCA), revealed three groups among the identified classes and two groups among individual compounds. The highest antioxidant activity was found for essential oils derived from the leaves (167.9 41 mg TE mL-1). Larvicidal potential against A. salina was observed in essential oils obtained from the leaves (LC50 6.40 μg mL-1) and spikes (LC50 6.44 μg mL-1). The in silico studies demonstrated that the main compounds can interact with acetylcholinesterase, thus showing the potential molecular interaction responsible for the toxicity of the essential oil in A. salina.

Unveiling the Antimicrobial and Larvicidal Potential of Butyrolactones and Orsellinic Acid Derivatives from the Morus alba-derived Fungus Aspergillus terreus via Integrated In vitro and In silico Approaches.

The emergence of multi-drug-resistant microbial strains spurred the search for antimicrobial agents; as a result, two distinct approaches were combined: four in vitro studies and four corresponding molecular docking investigations. Antituberculosis, anti-methicillin-resistant Staphylococcus aureus (anti-MRSA), antifungal, and larvicidal activities of the crude extract, two fractions, and seven isolated compounds from Aspergillus terreus derived from Morus alba roots were explored. The isolated compounds (5 butyrolactones and 2 orsellinic acid derivatives) showed potent to moderate antitubercular activity with MIC values ranging from 1.95 to 62.5 μg/mL (compared to isoniazid, 0.24 μg/mL) and promising anti-MRSA potential with inhibition zone diameters ranging from 8 to 25 mm. Additionally, the in silico study proved that the isolated compounds bind to the two corresponding proteins' active sites with high to moderate -(C-Docker interaction energies) and stable interactions. The isolated compounds displayed antifungal activities against different fungal strains at diverse degrees of activity, among them compound (8"S,9")-dihydroxy-dihydrobutyrolactone I eliciting the best antifungal activity. Meanwhile, all isolated compounds, fractions, and the crude extract demonstrated extremely selective potent to moderate activity against Cryptococcus neoformans. The isolated five butyrolactone derivatives could develop potential mosquito larvicidal agents as a result of promising docking outcomes in the larval enzyme carboxylesterase.

Insecticidal activities of the ethanolic extract of citrus fruit seeds for the control of Culex mosquitoes

Mosquitoes are among the significant vectors of public health concern. Culex mosquitoes have been implicated in spreading disease pathogens that inflicted both animal and man. The Hazards caused by using synthetic insecticide in controlling this vector cannot be overlooked. Thus, there is need to find alternative control method that is harmless and environment friendly. This research aimed to study the insecticidal activities of extract from four Citrus species seeds in the control of larval and adult stages of Culex mosquitoes. Different concentrations (1.0, 1.5, 2.0, 2.5, and 3.0%) of the extract was prepared using extraction solvent (ethanol) The highest percentage mortality of Culex larval was observed from application of 3.0% concentration of C. paradisi seeds extract within the period of exposure, 35.00%, 58.33%, 80.00%, and 100.00% larval mortality was recorded respectively. There is a significant difference (p < 0.05) comparing control and all the concentrations of Citrus seeds extract. Larvicidal potency of 3.0% seed extract concentration of C.sinensis, C.aurantium, C.aurantifolia, and C.paradisi are not statistically different (p > 0.05). The adulticidal potency of the seed oil varies with Citrus species. Citrussinesis seed oil gave higher percentage of adult Culex mortality in all the period of exposure. Statistically, the adulticidal potency of 2.5% concentration of all the Citrus seed oil are not different significantly (p > 0.05), expect the potency of C.aurantium seed extract. The lethal concentration requires for 50% (LC50) and 90% (LC90) of Citrus seeds oil extract varies with respect to period of exposure. Extract from Citrus seeds should be adopted for the control and management of insect vectors and it should be incorporated to integrated vector management (IVM) program.

Casearia tomentosa fruit extracts exposed larvicidal activity and morphological alterations in Culex quinquefasciatus and Aedes albopictus under in vitro and semi field conditions

Mosquitoes are notorious insects that transmit a wide range of infectious diseases, including zika, malaria, chikungunya, filariasis, and dengue. The overuse and incorrect application of synthetic pesticides to control mosquitoes has resulted in resistance development and environmental contamination, both of which have had a negative impact on human health. To address this issue, the larvicidal and pupicidal potential of acetone extract from Casearia tomentosa fruits was investigated. The extract was evaluated in a lab setting against all larval instars and pupa of Culex quinquefasciatus and Aedes albopictus, as well as against third instar larvae in a semi-field condition. Purified compounds through TLC were also tested against 3rd instar larvae of both mosquito and non-target organisms. The FT-IR and GC-MS analyses were used to characterise the extract. Morphological aberration caused by the acetone extract was observed using FESEM. The anal gills and respiratory siphon of both mosquitoes showed significant deformation from their normal state. 100 ppm was found to cause 100% larval mortality at 24 h of exposure in case of Cx. quinquefasciatus and at 72 h of exposure in Ae. albopictus larvae. After 72 h of exposure under in vitro conditions, the extract demonstrated considerable larvicidal activity with LC50 values of 38.33 and 47.56 against 3rd instar larvae of Culex quinquefasciatus and Aedes albopictus, respectively. The acetone extract can be considered as a highly effective mosquito larvicidal agent that is safe for the environment.Graphical abstract

Larvicidal potential of silver nanoparticles synthesized from Ocimum gratissimum leaf extracts against anopheles’ mosquito

Despite recent improvements in the methods used to eradicate and minimize mosquito populations, they still pose severe threats to human health. This study aimed to investigate the Larvicidal potentials of silver nanoparticles of Ocimum gratissimum on wild Anopheles larvae from Lagos. The plant used in this study was collected from the southeastern part of Nigeria, Ibite-Olo in Ezeagu Local Government Area of Enugu State. Wild Anopheles mosquito larvae were collected from a field at Kosofe Local Government Area of Lagos State, Nigeria where resistant Anopheline populations have been reported in and around Lagos State were brought to the laboratory and kept under standard insectary conditions (25–29 ℃;78–82% relative humidity). Aqueous extract of Ocimum gratissimum was made and subsequently into the silver nanoparticles. A bioassay test was performed according to WHO guidelines, with six different concentrations to assess the larvicidal activity and values obtained were subjected to log prohibit regression analysis to obtain LC50 and values with 95% confidence limit. The results of the larvicidal activities of the silver nanoparticles of Ocimum gratissimum showed that the mortality rate was dose-dependent with the percentage mortality increasing at a direct proportional rate as with dose and time of exposure. Ocimum gratissimum gave LC50 at 0.5 ppm and LC95 at 2.5 ppm respectively. The biosynthesized silver nanoparticles augmented the larvicidal activity of the silver nanoparticles of Ocimum gratissimum on wild Anopheles larvae from Lagos. Therefore, this study showed that the silver nanoparticles of Ocimum gratissimum have the potency to be used against an insecticide-resistant mosquito vector and are a suitable candidate for the development of novel natural insecticides.

Biosynthesis of selenium nanoparticles using cell-free extract of Xenorhabdus cabanillasii GU480990 and their potential mosquito larvicidal properties against yellow fever mosquito Aedes aegypti

Nanomaterials are successful due to their numerous applications in various domains such as cancer treatment, environmental applications, drug and gene delivery. Selenium is a metalloid element with broad biological activities and low toxicity especially at the nanoscale. Several studies have shown that nanoparticles synthesized from microbial and plant extracts are effective against important pests and pathogens. This study describes the bio fabrication of selenium nanoparticles using cell free extract of Xenorhabdus cabanillasii (XC-SeNPs) and assessed their mosquito larvicidal properties. Crystallographic structure and size of XC-SeNPs were determined with UV-a spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Energy-dispersive X-ray spectroscopy (EDAX), Zeta potential and Transmission electron microscopy (TEM). The significant surface plasmon resonance at 275 nm indicated the synthesis of XC-SeNPs from the pure cell-free extract of X. cabanillasii. The XRD result exhibits the crystalline nature of XC-SeNPs. The Zeta potential analysis confirmed that the surface charge of XC-SeNPs was −24.17 mV. TEM analysis revealed that synthesized XC-SeNPs were monodispersed, spherically shaped, and sized about 80–200 nm range. In addition, the larvicidal potentials of the bio-fabricated XC-SeNPs were assessed against the 4th-instar Ae. aegypti. XC-SeNPs displayed a dose-dependent larvicidal effect; the larval mortality was 13.3 % at the minimum evaluated concentration and increased to 72 % at higher dose treatments. The LC50 and LC90 concentration of XC-SeNPs against mosquito larvae were 79.4 and 722.4 ppm, respectively.

Biological evaluation of 1,3-benzodioxole acids points to 3,4-(methylenedioxy) cinnamic acid as a potential larvicide against Aedes aegypti (Diptera: Culicidae)

Aedes aegypti serves as the primary vector for viruses like dengue, Chikungunya, Zika, and yellow fever, posing a significant public health challenge in Brazil. Given the absence of approved vaccines for these diseases, effective mosquito control becomes paramount in preventing outbreaks. However, currently available chemical insecticides face issues related to toxicity and the emergence of resistance, necessitating the exploration of new active compounds. Drawing inspiration from natural products, we identified the 1,3-benzodioxole group as a key pharmacophore associated with insecticidal activity. Therefore, this study aimed to synthesize and assess the larvicidal activity of 1,3-benzodioxole acids against Ae. aegypti, as well as their toxicity in mammals. Among the compounds evaluated, 3,4-(methylenedioxy) cinnamic acid (compound 4) demonstrated larvicidal activity. It exhibited LC50 and LC90 values of 28.9 ± 5.6 and 162.7 ± 26.2 μM, respectively, after 24 h of exposure. For reference, the positive control, temephos, displayed both LC50 and LC90 values below 10.94 μM. These findings underline the significance of the 3,4-methylenedioxy substituent on the aromatic ring and the presence of a double bond in the aliphatic chain for biological activity. Furthermore, compound 4 exhibited no cytotoxicity towards human peripheral blood mononuclear cells, even at concentrations up to 5200 μM. Lastly, in mice treated with 2000 mg kg−1, compound 4 showed mild behavioral effects and displayed no structural signs of toxicity in vital organs such as the kidney, liver, spleen, and lungs.

Seasonal variation of essential oil from Murraya koenigii (Rutaceae) and insecticidal potential against Aedes aegypti (Diptera: Culicidae)

Murraya koenigii is a plant with exploited pharmacological potential and wide traditional use in Asian culture. This research investigated the chemical composition and seasonal variation of essential oil constituents of M. koenigii cultivated in the city of Goiânia, Goiás, region under climatic influence of the Cerrado domain. The larvicidal potential of these essential oils against Aedes aegypti was investigated. The constituents were evaluated by Gas Chromatography coupled to Mass Spectrometry (GC/MS). Climatological information and phenological conditions were also considered. Samples grouped into chemically similar sets were used in bioassays to investigate larvicidal activity. The results show the essential oil characterized by the majority presence of β-phellandrene, z-caryophyllene, α-pinene, sabinene and isodaucene. The phenological stage had more influence on the chemical composition of the essential oil than climatic factors. All essential oil samples were effective against Ae. aegypti, with no significant change in lethal concentrations.

Promising Larvicidal Effects of Nanoliposomes Containing Carvone and Mentha spicata and Tanacetum balsamita Essential Oils Against Anopheles stephensi.

The use of synthetic pesticides to control the spread of mosquito-borne diseases has causedenvironmental pollution and insecticide resistance in mosquitoes. Developments of new green insecticides havethus received more attention to overcome these problems. Nanoliposomes containing carvone and essential oils were first prepared. The nanoliposomephysicochemical characteristics (particle size, morphology, and successful loading) were then evaluated byDynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and the Attenuated Total Reflection-Fourier Transform InfraRed (ATR-FTIR) analyses. Larvicidal effects of carvone, Mentha spicata, and Tanacetumbalsamita essential oils were investigated against the main malaria vector, Anopheles stephensi, in non-formulatedand nanoformulated states. The larvicidal effects of nanoformulated states were significantly more potent (7.2 folds, 3.5 folds, and 8folds) than non-formulated states. Nanoliposomes containing M. spicata and T. balsamita essential oils with particlesizes of 175 ± 8 and 184 ± 5 nm showed the best efficacies (LC50 values = 9.74 and 9.36 μg/mL). The prepared samples could be used as new green potent larvicides against An stephensi mosquito infurther field trials. It is also recommended to investigate their efficacies against other mosquitoes.

Larvicidal and Fungicidal Activity of the Leaf Essential Oil of Five Myrtaceae Species.

Myrtaceae is one of the most diverse and abundant botanical families, exhibiting wide diversity in the chemical composition of essential oils (EOs). EOs have various biotechnological applications such as controlling the populations of organisms that negatively impact humans. This study aimed to extract EOs from Myrtaceae species, chemically characterize them, and evaluate their larvicidal and fungicidal effects. EOs were extracted from the leaves of Eugenia brasiliensis, Eugenia uniflora, Psidium cattleyanum, Psidium guajava, and Syzygium cumini by hydrodistillation for 3 h and characterized by chromatographic analysis. Larvaes of Aedes aegypti and colonies of Fusarium oxysporum were subjected to increasing EO concentrations to determine the larvicidal and fungicidal potential. The EOs of Eugenia and Psidium species are primarily composed of sesquiterpenes (>80 %), whereas S. cumini EO is rich in monoterpenes (more than 60 %). The Eugenia species had similar amounts of oxygenated monoterpenes, which may explain their higher larvicidal potential compared to other species, with CL50 of 86.68 and 147.46 PPM, respectively. In addition to these two study species, S. cumini showed a high inhibition of fungal growth, with more than 65 % inhibition. We demonstrated that the actions of five EOs from Myrtaceae with different biological activities are associated with chemical diversity.