Larvicidal Activity Research Articles

Design, Synthesis, and Evaluation of 7-Vinylcoumarin Derivatives as Agrochemicals: Biological Activities and Molecular Docking Insights.

The agricultural bioactivity of 7-alkenylcoumarin derivatives was investigated by synthesizing a series of coumarin derivatives containing 7-styryl fragments by introducing a styryl group at the 7-position of the coumarin scaffold through Pechmann cyclization, substitution, bromination, and Wittig reaction. The insecticidal effects and antifungal activities of these compounds against plant pathogenic fungi were evaluated. Bioactivity assessments revealed that compound 5i exhibited the highest larvicidal activity against Aedes aegypti, with a mortality rate of 96% after 24 h of treatment. Compounds 5i, 5e, and 5a displayed the strongest antifungal activity against Colletotrichum musae, with EC50 values of 0.42, 3.44, and 3.67 mg/L, respectively, outperforming the commercial fungicide bromothalonil (9.31 mg/L) and comparable to chlorothalonil (0.74 mg/L). Structure-activity relationship analysis indicated that the presence of a chlorine atom at the 4-position of the phenyl ring was critical for the bioactivity of the compounds. Docking results indicated that compound 5i exhibited the strongest binding affinity for succinate dehydrogenase, providing insights for further mechanistic studies. These findings suggest the significant potential of these compounds as lead candidates for in-depth research and development.

Natural Biphenyl-Type Neolignans as Resources of Pesticide Candidates: Assembly, Insecticidal Potency, and Cytotoxicity of Honokiol/Magnolol Analogues of Isoxazoline Hybridization via [3 + 2] Dipolar Cycloaddition.

Currently, the development of novel pesticides remains a crucial initiative to address the challenges of agricultural pest management. In pursuit of agrochemical candidates derived from plant natural products (NPs), 76 novel isoxazoline-hybridized honokiol/magnolol analogues were assembled via a [3 + 2] dipolar cycloaddition reaction, and their pesticidal potency and cytotoxicity were evaluated. Bioassays revealed that 13 compounds (5d, 6k, 7b-d, 7f, 7g, 8d-f, 13f, 15d, and 16h) exhibited superior larvicidal activity against Plutella xylostella Linnaeus with LC50 values in the range of 1.75-5.87 μg/mL, outperforming the botanical insecticide rotenone (LC50 = 26.7 μg/mL). Particularly, compounds 7c, 8d, and 15d showed over 11-fold higher larvicidal activity against P. xylostella than against rotenone. Meanwhile, compounds 5i, 6g, 7a, and 8a displayed better growth inhibitory effects on Mythimna separata Walker (LC50 = 0.13, 0.25, 0.34, and 0.35 mg/mL, respectively) compared to rotenone (LC50 = 0.53 mg/mL). Further greenhouse potted-plant assays revealed that compounds 8d and 15d showed superior in vivo control efficacy against P. xylostella compared to rotenone and comparable to tolfenpyrad and also demonstrated good protective effects on plants. Toxicity tests disclosed that these potent compounds exhibited moderate cytotoxicity to the human keratinocyte cell line (HaCaT), indicating a considerably favorable safety profile for skin exposure. Structure-activity relationship (SAR) analysis illustrated the importance of the exposed hydroxyls and newly introduced isoxazoline scaffolds in enhancing the insecticidal activity of these compounds. The novel scaffold, excellent insecticidal potency, and good safety profile position these compounds reported herein as promising leads for further pesticide candidates development. Furthermore, the present work offers valuable insights for advancing the NP-inspired agrochemical innovation.

Biosynthesis, characterization, and multifaceted applications of Elytraria acaulis synthesized silver and gold nanoparticles: Anticancer, antibacterial, larvicidal, and photocatalytic activities.

Green synthesis of metal nanoparticles using plant extracts has emerged as an eco-friendly alternative to conventional methods, offering potential applications in biomedicine and environmental remediation. This study demonstrates the successful biosynthesis of silver nanoparticles (SNPs) and gold nanoparticles (GNPs) using Euphorbia acaulis leaf extract as a reducing and capping agent. The nanoparticles were thoroughly characterized using UV-Vis spectroscopy, HR-SEM, EDX, TEM, AFM, XRD, and FTIR analyses, confirming their successful synthesis and revealing their predominantly spherical morphology with sizes ranging from 1 to 100nm. SNPs and GNPs exhibited significant anticancer activity against MCF-7 breast cancer cells, with IC50 values of 59.87μg/mL and 91.074μg/mL, respectively. The nanoparticles induce apoptosis and DNA damage in cancer cells, as evidenced by propidium iodide staining, DAPI staining, and comet assay. In antibacterial studies, SNPs demonstrated superior activity against both E. coli (17.00mm zone of inhibition) and S. aureus (10.77mm zone of inhibition) compared to GNPs. The nanoparticles also showed promising larvicidal activity against Aedes aegypti, with SNPs exhibiting higher potency (LC50: 20.81mg/L) than GNPs (LC50: 51.10mg/L). Histopathological analysis revealed significant tissue damage in SNP-treated larvae, particularly in the midgut, hindgut, muscles, and nerve ganglia. Additionally, both nanoparticles demonstrated photocatalytic activity in degrading methylene blue dye, with SNPs showing superior performance. These findings suggest that biofunctionalized SNPs and GNPs synthesized using E. acaulis possess multiple biological applications, making them promising candidates for various biomedical and environmental applications.

Activity of Essential Oils From Pentanema indicum (L.) Y. Ling and Chromolaena odorata (L.) R.M.King & H. Rob Against Three Mosquito Species

ABSTRACTMosquitoes act as biological carriers spreading numerous vector borne diseases globally. The present research aimed to study the effect of essential oils (EOs) from Pentanema indicum (L.) Y. Ling and Chromolaena odorata (L.) R.M. King & H. Rob against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes. Concentrations of 3.125, 6.25, 12.5 25 and 50 ppm were tested for their mosquitocidal properties. The essential oil (EO) from P. indicum demonstrated promising ovicidal activity, achieving 100% efficacy against Ae. aegypti and Cx. quinquefasciatus and 76% efficacy against An. stephensi at a concentration of 50 ppm within 24 h. Similarly, C. odorata exhibited significant activity at higher concentrations, with ovicidal rates of 72% for Ae. aegypti, 79% for An. stephensi and 64% for Cx. quinquefasciatus at 300 ppm after 72 h. In terms of larvicidal activity, P. indicum showed potent toxicity with LC50 values of 4.28 ppm for Ae. aegypti, 14.01 ppm for An. stephensi and 5.47 ppm for Cx. quinquefasciatus. Additionally, C. odorata exhibited considerable mosquito larvicidal activity at higher concentrations, with LC50 values of 95.28 ppm for Ae. aegypti, 98.95 ppm for An. stephensi and 89.05 ppm for Cx. quinquefasciatus after 24 h. However, no significant pupicidal activity was observed for both EOs. GC–MS analysis identified β‐Pinene (14.31%), D‐Limonene (13.48%) and Caryophyllene (25.48%) as the main components in P. indicum. The EO from C. odorata contained α‐Pinene (12.10%), Geijerene (11.62%) and Caryophyllene (10.64%) as the primary components; probably these compounds were responsible for the observed activities. Toxicity studies indicated that the EOs from both plants had no adverse effects on natural predators. The EOs were then formulated for field application and tested in a laboratory setting; they demonstrated promising mosquitocidal activity without harming natural predators. This study suggests that EOs from P. indicum and C. odorata offer an effective alternative to synthetic pesticides.

Larvicidal and adulticidal activity of irradiated Thuja orientalis essential oil by gamma radiation for controlling Culexpipiens.

Culex pipiens mosquitoes are the primary vector of the West Nile virus worldwide and have a wide distribution. To avoid the development of resistance in insect pests to conventional synthetic pesticides, there have been many attempts to study botanical pesticides. The increasing resistance of insect pests to synthetic pesticides is a threat to the diversity of ecosystems, which makes the study of botanical pesticides all the more important. The study aimed to determine the efficacy of Thuja orientalis essential oil irradiated with 1, 3 and 5KGy compared to unirradiated T. orientalis as larvicidal agents against the third instar larvae of C. pipiens using six different concentrations (15, 20, 25, 30, 35 and 40ppm) and as an adulticidal agent against approximately three-day-old female adults 0.2, 0.4, 0.6, 1 and 2%. The results generally showed that the irradiated essential oil with 5KGy had the highest efficacy by LC50 (20.16ppm) followed by essential oil irradiated with 3 and 1KGy (LC50, 23.16 and 26.00ppm, respectively) compared to unirradiated ones (LC50, 27.28ppm) after 24h from the exposure for the third instar larvae. The knockdown effect for adults increased significantly with higher concentrations of the oil, across different exposure times ranging from 5 to 60min. The time to knock down 100% of mosquito population to Thuja orientalis essential oils at the highest concentration 2% were 20min at 0, 1, and 3KGy and 10min at 5KGy. Our results indicate that gamma irradiation of T. orientalis fruit improves the efficacy of their essential oil against Culex pipiens and the irradiated oil could be successfully used for management of these insects. The head capsule, antenna, and the last abdominal segments of the 3rd instar larvae exposed to the essential oil of unirradiated or irradiated Thuja orientalis unripe were examined by the scanning electron microscope (SEM).

Exploring the larvicidal potential and phytochemical composition of Solanum incanum extracts: Insights from molecular docking and GC–MS analysis

AbstractDespite continuous efforts to control mosquito populations and disease vectors, they remain prevalent globally and pose significant health risks. Botanicals have garnered increasing attention as alternatives to synthetic insecticides due to their broad‐spectrum insecticidal properties, biodegradability, and environmental compatibility. This study aimed to evaluate the larvicidal efficacy of Solanum incanum Soxhlet extracts using various solvents. Additionally, we conducted a phytochemical analysis of the methanol extracts using gas chromatography–mass spectrometry (GC–MS) and performed molecular docking studies. The methanol extract of S. incanum demonstrated significant larvicidal activity, with LC50 values of 266.75, 214.52, and 90.15 μg/mL at 24, 48, and 72 hours post‐treatment, respectively. GC–MS analysis identified several compounds in the methanol extract, with trans‐9‐Octadecenoic acid, pentyl ester (17.99%) and propanoic acid, 2‐(3‐acetoxy‐4,4,14‐trimethylandrost‐8‐en‐17‐yl) (14.42%) being the most abundant. The methanol extract exhibited the highest phenolic content, with 1.44 mg GAE/g. The IC50 values for the DPPH assay were 1.69 mg/mL for the ethyl acetate extract and 6.7 mg/mL for the methanol extract. Furthermore, molecular docking supported the findings, with propanoic acid, 2‐(3‐acetoxy‐4,4,14‐trimethylandrost‐8‐en‐17‐yl) emerging as the top compound for all targets tested, including AChE (−9.4 kcal/mol), GABA‐T (−8 kcal/mol), and ATPase (−7.9 kcal/mol). These results provide valuable insights into the potential application and development of bioinsecticides.

Evaluation of the antimicrobial and larvicidal activities of n-hexane root extract of Ixoria coccinea L. (Rubiaceae)

The antimicrobial as well as the larvicidal activities of n-hexane root extract of Ixoria coccinea against Aedes aegypti was evaluated in this work. The extraction was done using maceration method. Agar well diffusion method was used to assess the antimicrobial activity of the extract against different clinical isolates of gram positive and gram-negative bacteria. The larvicidal activity was evaluated according to World Health Organization (WHO) guideline for larvicidal assay as follow: a stock solution of 10mg/ml was prepared for each extract from which five different concentrations (1.0, 2.0, 3.0, 4.0 and 5mg/ml in 100ml) were made and used for the test. A control was also prepared for each extract. A total of 20 larvae were used for each of the concentration and mortality was recorded at 24, 48 and 72 hours. The result of the antimicrobial assay showed that at 100mg/ml concentration, the extract gave an inhibition zone diameter of 17±1.41mm for Staphylococcus aureus, 8±0.82mm for Bacillus spp, 2±0.00mm for Stapylococcus epidermidis, 4±0.58mm for Pseudomonas aeruginosa and 6±1.29mm for Escherichia coli. The extract was most active against Staphylococcus aureus with an MIC of 50mg/ml. The extract is not active against all the fungi species used in the test. Examination of the result for larvicidal assay against Aedes aegypti larvae showed that the LC50 after 24, 48 and 72 hours are 1.782, 1.376 and 0.686mg/ml respectively. At concentration of 3mg/ml there was 100% mortality after 72 hours. The results showed that the n-hexane root could serve as a source of both antibiotic and mosquito larvicides

Larvicide activity of ethanol extracts from Zodia (Evodia suaveolens S.) leaves and Cananga (Cananga odorata) flowers on Aedes aegypti larvae

Controlling Aedes aegypti population in Dengue management programs is often carried out using high doses of synthetic insecticides, such as temephos, that may lead to resistances. An alternative of natural ingredient such as Zodia (Evodia suaveolens S.) leaves, that containing evodiamine and Cananga (Cananga odorata) flower that containing linalool, appears to be a promising larvicide. This study aims to determine the effectivity of ethanol extracts from Zodia leaves and Cananga flowers on the mortality of Aedes aegypti larvae. This experimental study using Aedes aegypti larvae at stage of III-IV. Each ingredient was extracted by the maceration method and then prepared at concentration of 2.5% and 5%. PEG 400 was also added as a diluent. Observations performed every 6 hours, for 24 hours. Data analysis using Kruskal Wallis test and Dunn's test. Within 24 hours, in each of study group, there was 100% larval mortality. The Kruskal Wallis test resulting p-value of <0.05. From Dunn’s test, comparisons between each study group and the negative and positive control groups yielded p-values <0.05 and 1.000, respectively. Thus, it can be said that ethanol extracts from Zodia leaves and Cananga flowers are as effective as temephos as larvicide on Aedes aegypti larvae

Larvicidal activity, phytochemical and GC-MS analysis of crude extract derived from <i>Ceriop decandra</i> (Griff) against <i>Aedes aegypti</i> (Linnaeus)

Larvicidal activity, phytochemical and GC-MS analysis of crude extract derived from <i>Ceriop decandra</i> (Griff) against <i>Aedes aegypti</i> (Linnaeus)

Synthetic Strategies for the Development of Novel Heterocycles as Larvicides Targeting Aedes aegypti Linn.

Owing to their extensive utilization as pesticides, heterocycles assume a fundamental role in the management of vector-borne diseases. Despite the presence of numerous heterocyclic compounds in commercial insecticides and larvicides, resistance to pesticides still demands novel strategies to current pest control methods. Considering these facts, this review aims to survey the synthesis and SAR of heterocyclic molecules with larvicidal activity against Aedes aegypti Linn. Comprehensive searches across the major databases were conducted to identify heterocyclic compounds exhibiting larvicidal efficacy against Ae. aegypti with the goal to unveil the main characteristics that are essential for exhibiting larvicidal activity. Active compounds display LC50 values varying from 0.36 to 2907 μM. Fifteen heterocyclic compounds displayed larvicidal activities below 20 μM. Five-membered ring molecules containing nitrogen and oxygen have displayed larvicidal activity according to the position of heteroatoms in the ring. Molecules bearing 1,2,4-oxadiazole and 1,2-oxazole moieties have been shown to be more active than 1,3,4-oxadiazole derivatives. Compounds possessing the indole scaffold have proven to be more potent than isatin and pyrimidine derivatives. Structural characteristics other than a heterocyclic moiety, such as the presence of halogens and less ionized and polar molecules, may also play a role in determining the final larvicidal activity. The rationale behind this review is to stimulate the discovery of innovative heterocyclic larvicides. Thus, it is important to continue synthesizing new scaffolds to comprehensively elucidate the structure-activity relationship for each heterocyclic moiety outlined in this investigation.

Chemical structure-biological activity of 1,4-naphthoquinone analogs as potential Aedes aegypti larvicides.

1,4-Naphthoquinone compounds have shown pesticidal activity against Aedes aegypti larvae, a key vector of diseases such as dengue and Zika. However, limited knowledge of their structure-activity relationships has hindered their optimization for pesticide development. This study investigates the structure-activity relationships of 1,4-naphthoquinone, particularly 2-hydroxy-1,4-naphthoquinone and its derivatives. A series of 1,4-naphthoquinones with modifications at the C-2, C-5, and C-8 positions were synthesized and tested for larvicidal activities against Ae. aegypti. The presence of chlorine substituents at the C-2 position significantly increased mosquito larval mortality. In contrast, 2-hydroxy and 2-methoxy groups were less effective, highlighting the importance of the C-2 substituent in determining larvicidal activity. The compounds were tested on both pyrethroid-susceptible Orlando 1952 (ORL1952) and permethrin-resistant Puerto Rico (PR) strains of Ae. aegypti. While compound 1d exhibited the lowest median lethal concentration (LC50) against ORL1952 larvae, it showed minimal activity against the PR strain, which is resistant. The most promising compounds, 1 and 4a, showed LC50 values of 2.764 and 4.916 ppm in the ORL strain, and 2.548 and 4.878 ppm in the PR strain, respectively. Chlorine substitution at the C-2 position of 1,4-naphthoquinones enhances larvicidal activity against Ae. aegypti, while 2-hydroxy and 2-methoxy substitutions reduce efficacy. Certain compounds, such as 1 and 4a, show potential as broad-spectrum agents effective against both susceptible and resistant strains of Ae. aegypti, highlighting their promise for further development as mosquito control agents. © 2025 Society of Chemical Industry.

Characterization of some selected macroalgae extracts and assessment of their insecticidal and genotoxicity in Culex pipiens L. mosquito larvae

The continual use of synthetic insecticides to control mosquito larvae has severe implications for human health and the ecosystem, highlighting the need for alternative natural insecticides. Macroalgae may be a good alternative because of their biologically active metabolites with distinctive chemical structures that have been reported for their insecticidal properties. The study aimed to investigate the potential of different extracts from Jania rubens (Linnaeus) J.V.Lamouroux and Colpomenia sinuosa (Mertens ex Roth) Derbès & Solier as genotoxic and larvicidal agents against Culex pipiens Linnaeus larvae. The algae thallus was subjected to extraction using methanol, acetone, and methylene chloride. The phytochemical composition was quantified. The larvicidal activity of the different algae extracts was assessed against the third instar larvae of Culex pipiens. Genotoxic evaluation through comet assays and compound characterization by GC/MS was done. The results demonstrated that J. rubens methylene chloride extract exhibited the highest contents of phenolics, alkaloids, flavonoids, terpenoids, and tannins while C. sinuosa methanol extract demonstrated the highest levels of flavonoids, alkaloids, phenolics, and saponins. The larvicidal activity results revealed that J. rubens methylene chloride extract was the most toxic for C. pipiens larvae with LC50 = 9.30 ppm followed by C. sinuosa acetone extract with LC50 = 82.58 ppm after 72 h of exposure. At 50 and 250 ppm, J. rubens methylene chloride and C. sinuosa acetone extracts maintained 100 and 93.33% larval mortality rates, respectively. Comet assay results demonstrated the genotoxicity of both algae extracts in C. pipiens larvae. This study would be a beginning towards replacing chemical insecticides with algae-based bioinsecticides against C. pipiens mosquitos.

Evaluation of hesperidin as a potential larvicide against Culex pipiens with computational prediction of its mode of action via molecular docking

Hesperidin, a natural flavanone glycoside predominantly found in citrus fruits, has gained attention for its wide-ranging biological activities, including potential insecticidal properties. Culex pipiens, commonly known as the northern house mosquito, is a major vector of several human pathogens, such as the West Nile virus and filariasis, making it a key target in the fight against vector-borne diseases. In this study, we evaluated the larvicidal activity of Hesperidin against Culex pipiens larvae, assessing its potential as an alternative to chemical insecticides. Hesperidin demonstrated potent larvicidal effects, with a lethal concentration 50 (LC50) of 570.3 ± 0.04 µg/mL, outperforming the conventional insecticide Chlorpyrifos 588.3 ± 0.28 µg/mL in efficacy. Molecular docking simulations revealed a strong binding affinity between Hesperidin and crucial neuroreceptors in Culex pipiens, particularly acetylcholinesterase (AChE), a key enzyme involved in nerve signal transmission. The interaction between Hesperidin’s hydroxyl groups and the AChE enzyme’s active site suggests that AChE inhibition is the primary mechanism driving Hesperidin’s insecticidal action. These findings position Hesperidin as a promising, environmentally friendly alternative to synthetic insecticides. However, further research is needed to assess its toxicity to non-target organisms and optimize its formulation for broader application in mosquito control.

Enhanced Mosquito Larvicidal Efficacy and Dehairing Properties of Bacillus thuringiensis Serovar israelensis Strain VCRC-B649 Isolated from Malabar Coast, India.

In recent years, there has been a global threat from emerging vector-borne diseases (VBD), despite the implementation of several vector control programs. Considering the benefits of bacterial pesticides, the present study aimed to isolate potential mosquitocidal bacteria from the various soil types collected from the Kasaragod (12.5°N, 75.0°E) district of Kerala, India. One bacterial strain was isolated from the coastal alluvium soil and showed promising mosquitocidal activity. The mosquitocidal isolate was identified as Bacillus thuringiensis serovar israelensis strain VCRC-B649 through phylogenetic analysis of whole genome sequence. LC50 values against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi larvae were determined as 0.0064, 0.0072, and 0.0101mg/L, and LC90 values were 0.0127, 0.0140, and 0.019mg/L. Comparative analysis of larvicidal activity of this strain has revealed more efficacy than the WHO reference strain of B. thuringiensis var. israelensis (H14) The cry and cyt gene profile of this isolate is found to be similar to WHO reference strain of B. thuringiensis var. israelensis (H14). This new isolate has not shown any adverse effects against aquatic non-target organisms. Further evaluation of its morphological, biochemical characteristics and growth kinetics revealed similarities with already reported B. thuringiensis strains. Sporulated culture at 72h showed maximum (20.6 ± 1.5mm) proteolytic activity and animal skin (goat skin) dehairing property and revealed the industrial applications of this new strain. This is the first report on the isolation of mosquitocidal bacterial strain with enzyme-producing property from the Malabar coastal region and it was proven to be a more suitable alternative biocontrol agent for controlling the disease transmitting mosquito vectors with translational value.

Synthesis and Insecticidal/Fungicidal Activities of Triazone Derivatives Containing Acylhydrazone Moieties.

A series of novel triazone derivatives containing aldehyde hydrazone or ketone hydrazone moieties were designed, synthesized and their biological activities were investigated against Aphis craccivora, Culex pipiens pallens, Helicoverpa armigera, Ostrinia nubilalis, Mythimna separata and 14 Kinds of fungi. Most of the aldehyde hydrazone exhibited excellent insecticidal activities against A. craccivora. In particular, the aphicidal activities of compounds 3t (35%) and 3w (30%) were equivalent to pymetrozine (30%) at 5 mg/kg. The aphicidal activities of derivatives 3p, 3u, 3y, 5g, 5i, 5l, 5q and 5u against C. pipiens pallens were higher than that of pymetrozine. Compound 3u (100%) exhibited good larvicidal activities against C. pipiens pallens at 0.25 mg/kg. Most derivatives exhibited broad-spectrum fungicidal activities against 14 kinds of plant fungi at 50 mg/kg. Thirty-nine compounds exhibited a more than 50% inhibition rate against Physalospora piricola. Compounds 3h, 3t and 3w were expected to be the leading structure for the development of new triazone insecticides agents.

Exploration of Secondary Metabolites in Platostoma menthoides (L.) Using Ethyl Acetate Extract and Its Antibacterial, Antioxidant, and Larvicidal Activities.

Recently, there has been a growing demand for plant-based products to treat a range of health conditions. Platostoma menthoides (L.), a member of the Lamiaceae family, is widely known for its versatile therapeutic properties. The primary aim of this study is to analyze and identify the secondary metabolites found in the extract of P. menthoides obtained using ethyl acetate and to assess its antioxidant, antimicrobial, and mosquito larvicidal properties for the first time. For the chemical profiling, a GC-MS analysis of the extract was conducted, and it showed the presence of various phytoconstituents, and the FT-IR spectrum revealed the functional groups associated with them. The quantitative phytochemical estimations revealed values of 34.87 ± 0.53 mg of GAE equivalents/g and 22.19 ± 1.11 mg of QUE equivalents/g, respectively, for total phenolic and flavonoid content. The biological studies of P. menthoides extract showed potent mosquito larvicidal activity against fourth instar larvae of Aedes aegypti at a 100 µg/mL concentration with LC50 and LC90 values of 81.328 and 161.471 µg/mL, respectively. Moreover, the DPPH and FRAP radical scavenging potentials were evaluated, and the results revealed their ability to scavenge the free radicals. The extract also showed higher antibacterial effects against gram-negative bacteria when compared to gram-positive bacteria. All these findings suggest that P. menthoides is a rich source of phytoconstituents with various medicinal applications and can be used as an antioxidant, antibacterial, and mosquito-larvicidal agent.

Larvicidal and adulticidal activities of Cymbopogon citratus synthesized silver nanoparticles in different mosquito vectors

Larvicidal and adulticidal activities of Cymbopogon citratus synthesized silver nanoparticles in different mosquito vectors

Phytochemical evaluation and antioxidant potential of Echinodorus macrophyllus extracts

Abstract Belonging to the Alismataceae family, Echinodorus macrophyllus, known in Brazil as “chapéu de couro”, is popular in the food industry, where it is used in teas and infusions. The objective of this study was to evaluate the active chemical compounds in the powder of E. macrophyllus leaves extracted by two different methods (Soxhlet [SXT] and ultrasound-assisted extraction [UAE]), quantify the total phenolic compound (TPC) and total flavonoid (TFC) content, and evaluate the antioxidant potential and larvicidal activity. The SXT extraction was the most efficient (6.05% yield). Analysis by thin-layer chromatography (TLC) and high-performance liquid chromatography with a diode array detector (HPLC-DAD) evidenced the presence of cinnamic acid derivatives, flavones, and flavanones in the extracts. The TPC was higher in the SXT extract (7.71±0.05 µg GAE/mL). However, there was no significant difference in TFC. The SXT extract exhibited greater antioxidant potential according to the ferric reducing antioxidant power (FRAP) method (IC50=3.37±0.45 µg/mL), while the UAE extract showed higher activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50=42.16±5.79 µg/mL). Both extracts were nontoxic to Artemia salina, suggesting the potential health benefits of this plant, which is rich in phenolic compounds and diverse pharmacological properties.

In-vitro effect of the methanolic extract of Morinda citrifolia against the life cycle of Dermatobia hominis

Background: bovine cutaneous dermatobiosis or furuncular myiasis caused by Dermatobia hominis is a parasitosis that mainly affects bovines in the tropics and represents a particular interest in public health as zoonosis. Its control is based on ivermectins, which have long withdrawal times, affecting the productive dynamics within dairy cattle herds. Objective: to assess the in-vitro effect of the methanolic extract of the M. citrifolia ripe fruit against the life cycle of D. hominis. Methods: D. hominis larvae were taken directly from naturally parasitized bovine skins. These larvae were exposed by immersion to different concentrations of the methanolic extract of M. citrifolia (10, 50, 100, 200, 300, 400, 460 mg/mL) diluted in distilled water. Ivermectin 1% was used as a positive control, and distilled water as a negative control. Subsequently, the larvicidal activity was evaluated in the first 48 hours post-immersion (PI), the pupicidal activity within 10 to 23 days PI, and the inhibition of the imagos emergence as well as their anatomical alterations, were evaluated within 24 to 35 days PI; recreating the pupal development and their hatching in the soil under controlled laboratory conditions. CL50 and CL90 for the larvae phase were estimated through Probit regression analysis. Results: M. citrofolia concentrations of 400 and 460 mg/mL had a significant (p<0.05) larvicidal effect of 40% (95% CI 34.7 - 43.9) and 60% (95% CI 56.8 - 67.3), respectively. The pupicidal effect on the surviving larvae was significant (p<0.05) at 300, 400, and 460 mg/mL: 40% (95% CI 37.9 - 42.3), 60% (95% CI 55.7 - 65.9) and 70% (CI 95% 67.1 – 76.7), respectively. The inhibition of the emergence of imagos was significant (p<0.05) 50% (95% CI 42.3 - 57.8) in all concentrations equal to or greater than 200 mg/mL. Finally, 20% (95% CI 12.6 - 29.3) of the emerging imagos at 460 mg/mL presented morphoananomic alterations (p<0.05). The LC50 and LC90 estimated (larval phase) were 22.36 mg/mL (95%CI 15.06-33.19) and 245.08 mg/mL (95%CI 165.10-363.82), respectively. Conclusions: The methanolic extract of M. citrifolia was effective as larvicide, altering the pupation and the emergence of imagos of D. hominis. In addition, it modified the imagos morphoanatomy; interesting results to promote in-situ and other bioguided fractionation studies of this extract in different D. hominis stages; being M. citrifolia a plant species widely adapted to the conditions of the Meta department, Colombia.

Phyto-synthesis of selenium nanoparticles using Mentha spicata (mint) extract and its larvicidal and antibacterial activities

Phyto-synthesis of selenium nanoparticles using Mentha spicata (mint) extract and its larvicidal and antibacterial activities