Search Results (409)

The Asian medicinal plant Cipadessa baccifera (Roth) Miq., also known as C. fruticosa or C. cinerascens (Ranabili or Nalbila), has long been used in Ayurvedic medicine to treat dysentery, skin disorders, rheumatism and parasitic infections. Extracts prepared from the leaves, seeds or fruits of the plant have revealed activities against mosquito vectors of parasitic diseases, notably marked larvicidal activities. Plant extracts have shown insecticidal and antibacterial activities, in addition to antioxidant effects. Numerous natural products at the origin of these pharmacological effects have been identified from all parts of the plant, from roots to leaves and seeds. The phytochemical survey presented here led to the identification of about 200 natural products isolated from C. baccifera, including a large majority of limonoids (>170), in addition to steroids, terpenoids, and a few other products. The panel of limonoids is extremely diversified with multiple groups of compounds: cipacinerasins, cipacinoids, cipacyclonone, cipadesins, cipadessains, cipadessalide, cipadonoids, cipafera, cipaferens, cipaferoids, ciparasins, cipatrijugins, cineracipadesins, cinerascenoids, and cipacinerasins. There are a few interesting bioactive products in Cipadessa, such as the anticancer agents cipaferen G and cipacyclonone, and the anti-inflammatory molecules cipadessain D and methyl-angolensate. Other bioactive products are discussed, such as cryptomeridiol, khayasin T, and febrifugin. An overview of Cipadessa phytochemicals is provided here to shed light on this under-valued medicinal plant. Full article

Spodoptera frugiperda is a major pest affecting maize production worldwide, and its control relies heavily on synthetic insecticides, which generate environmental risks and resistance. Essential oils (EOs) represent a promising alternative due to their biodegradability and the biological activity of their terpenoid constituents. This study evaluated the chemical composition, larvicidal activity, and acetylcholinesterase (AChE) inhibitory potential of the EOs from Origanum vulgare, Lavandula dentata, and Mentha piperita against S. frugiperda larvae at the L1, L2, and L4 instars. Chemical characterization by GC–MS revealed distinct chemotypes: a phenolic/terpenoid profile in O. vulgare, a 1,8-cineole-type profile in L. dentata, and a menthol-rich composition in M. piperita. Larvicidal assays showed dose- and stage-dependent responses, and M. piperita EO tended to produce the most robust mortality across instars and times, consistently producing high mortality (75%) at 90 µg·mL⁻¹ air concentration. AChE inhibition assays revealed that carvacrol and menthone were the most active constituents with IC₅₀ values of 312–330 µg·mL⁻¹. Molecular docking supported these results, as carvacrol and menthone showed the most favorable interactions with amino acid residues of the AChE catalytic site. These data support their suitability as candidates for integrated pest management programs targeting S. frugiperda. Future research should focus on formulation strategies, synergistic combinations, detoxification mechanisms, and field validation. Full article

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an agricultural pest of global economic importance. Its ability to reproduce, adapt, and develop resistance necessitates the creation of effective and environmentally friendly alternative control strategies. This study aimed to evaluate the larvicidal activity of three nanoformulations (NFs) based on the essential oil (70% safrole) of Piper auritum Kunth (Piperales: Piperaceae), nanoemulsion (NE), microemulsion (ME), and silver nanoparticles (AgNPs), against second-instar larvae of S. frugiperda. The NFs were prepared using a combination of low- and high-energy methods, using Tween 80 and Span 80 as stabilizing agents. The droplet sizes of the NFs ranged from 19 to 48 nm. Stability analysis of the formulations maintained for 60 days in open systems at room temperature allowed the identification of remaining oxidized sesquiterpenes and phenylpropanoids. In in vitro bioassays, the NE demonstrated the highest larvicidal activity, with an LD₅₀ of 0.97 µg cm⁻², outperforming the other formulations by a factor of ten. Observations of morphological damage to larval and pupal tissues, along with deformation of adult specimens, confirming the toxicity of the NFs. These findings highlight the potential of essential oil-based NFs derived from P. auritum as sustainable biopesticides for integrated pest management. Full article

Dengue is the most concerning mosquito-borne neglected tropical disease globally. The disease is caused by the dengue virus (DENV) and transmitted by the vector mosquito species belonging to the genus Aedes Meigen, 1818, particularly Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1895). In 2024, global cases of dengue exceeded 7.6 million, with India reporting 233,519 cases. These statistics underscore the ongoing challenge of managing dengue outbreaks worldwide. For generations, tribal communities across India have employed medicinal plant-based extracts as mosquito and other insect repellents. Plant-based phytochemicals are largely preferred over synthetic insecticides due to their perceived safety, non-toxicity to non-target organisms, and environmental sustainability. This review provides a comprehensive overview of various phytochemicals extracted from Indian medicinal plants for their larvicidal activity against Aedes mosquitoes. Furthermore, the article also reviews the mode of action of these phytochemicals, including neurotoxicity, mitochondrial dysfunction, sterol carrier protein-2 inhibition, midgut cytotoxicity, insect growth regulation disruption, and antifeedant activity, which aids in formulating dengue vector control strategies. Based on this review, Ecbolin B from Ecbolium viride, Alizarin from Rubia cordifolia, and Azadirachtin from Azadirachta indica exhibited better larval mortality rates against Ae. aegypti, with LC50 values recorded at 0.70, 1.31, and 1.7 ppm, respectively. Full article

The frequent and indiscriminate use of all classes of synthetic anthelmintics to deworm small ruminants has decreased their effectiveness in a worldwide problem of anthelmintic resistance. Using active plant metabolites with anthelmintic properties has become a suggested alternative to control parasitic helminths. The present study investigated the ovicidal and larvicidal activity of a fraction (CnF4) containing protocatechuic acid (3,4-dihydroxybenzoic acid) from Chamaecrista nictitans (Fabaceae) and a commercial standard of protocatechuic acid against strains of the parasitic nematode Haemonchus contortus susceptible (HcIVM-S) and resistant (HcIVM-R) to ivermectin, using egg hatch inhibition (EHI) and L3 larval mortality assays. The CnF4 fraction showed an EHI greater than 90% at 0.8 mg/mL against HcIVM-S and an EHI = 88.39% at 1.6 mg/mL against HcIVM-R. The commercial standard of protocatechuic acid displayed an EHI of 97.49% at 0.25 mg/mL against HcIVM-S and an EHI greater than 98% at 0.5 mg/mL. In the larval mortality assays, protocatechuic acid caused 72.4% larval mortality of HcIVM-S at 8 mg/mL and 53.2% mortality of HcIVM-R at 16 mg/mL. These results indicate that protocatechuic acid was more effective in inhibiting egg hatching and causing larval mortality against HcIVM-S compared to HcIVM-R. Full article

Mtx1 is a mosquitocidal protein that exhibits high toxicity toward Culex species. It is produced during the vegetative phase of Lysinibacillus sphaericus but at very low levels and is rapidly degraded. The low expression appears to result from a weak promoter and a potential regulatory stem-loop structure in the 5′ untranslated region. To investigate this regulation, promoter variants of mtx1 were constructed to disrupt stem-loop formation, and promoter activity was assessed using green fluorescent protein (GFP) as a reporter. Disruption of the inverted repeat resulted in approximately twofold higher fluorescence compared with the wild-type promoter in L. sphaericus 2297, indicating partial derepression of translation. To improve protein stability, Bacillus subtilis WB800N, a protease-deficient host, was employed for heterologous expression. Truncated Mtx1 (tMtx1) was secreted into the culture medium, and no obvious degradation products were detected by Western blot analysis under the conditions tested. Although the overall yield was low and not quantitatively determined, the secreted protein retained biological activity. Larvicidal assays showed elevated mortality in tMtx1-containing culture supernatants, with an estimated LC₅₀ at approximately a 1:83 dilution and detectable activity up to a 1:512 dilution relative to control cultures. These results demonstrate that the upstream inverted repeat contributes to partial repression of mtx1 expression in L. sphaericus and that protease-deficient B. subtilis can be used as a host for producing biologically active tMtx1, although further optimization will be required to improve yield. Full article

Background and Clinical Significance: Furuncular myiasis is a tropical parasitic skin infestation caused by dipterous fly larvae, most commonly affecting travellers to endemic regions. While returning travellers typically present with one or few lesions, extensive parasitism is rare. Increased global mobility and expanding ecological range of myiasis-causing species underscores the need for clinicians in endemic and non-endemic regions to recognise, diagnose, and manage this condition promptly. Awareness of exposure risks—including soil contact, infested clothing, and poor living conditions—is essential to reducing morbidity and preventing complications like secondary bacterial infection. Case Presentation: A healthy male in his forties returned to the UK after a month-long visit to rural Ethiopia, during which he slept on dirt floors and hung his washing on a line. He developed pruritic papular lesions that progressed to erythematous furuncles with central puncta and purulent discharge, accompanied by sensations of movement. The patient self-extracted 12 larvae in Ethiopia and subsequently sought local medical attention, receiving Albendazole, after which emerging larvae were non-motile. On UK presentation, he had 27 lesions at varying stages, 3 with signs of secondary infection. Laboratory investigations revealed elevated inflammatory markers, and wound swabs grew scanty Streptococcus pyogenes. Management included wound occlusion and systemic antibiotics. No further larvae were retrieved, precluding definitive speciation. All lesions improved over subsequent reviews. Conclusions: This case illustrates an unusually extensive presentation of presumed Cordylobia spp. myiasis in a returning traveller, highlighting potential complications following larvicidal therapy. Clinicians should maintain a high index of suspicion for myiasis in patients with compatible cutaneous lesions and relevant history. Increasing travel and shifting vector distributions make familiarity with tropical dermatoses and provision of effective safety measures essential in clinical practice. Full article

Gastrointestinal nematodes are among the most significant parasites affecting livestock health and productivity, leading to major economic losses and contributing to the global increase in resistance to anthelmintics. Biological control using fungi with ovicidal and nematophagous activity offers an environmentally friendly alternative. This trial represents the first long-term field evaluation in cattle of the commercial combination of D. flagrans and P. chlamydosporia under natural infection conditions. Eighteen Holstein × Zebu males (12–15 months old) were divided into three groups (n = 6): T1 (D. flagrans), T2 (D. flagrans + P. chlamydosporia), and control. Treatments were administered orally daily (6 g/100 kg BW of each fungus; 10⁶ chlamydospores/g) for nine months. Fecal egg counts (EPG) and infective larvae in pasture (L3) were monitored. Groups T1 and T2 showed significantly lower EPG values than the control during most of the experimental period. Haemonchus spp. was identified as the predominant nematode, supporting its epidemiological relevance. The combined fungal treatment exhibited enhanced effectiveness, enhancing parasite suppression through complementary ovicidal and larvicidal mechanisms. This approach offers a sustainable alternative to the excessive use of chemical compounds and has the potential to contribute to integrated animal health and livestock production. Full article

A series of novel triazone derivatives containing acylhydrazone and phenoxypyridine motifs were designed, synthesized, and evaluated for their biological activities. The bioassay results indicated that most of the target compounds exhibited excellent insecticidal activities against bean aphids. In particular, compounds 3i and 3e showed excellent aphicidal activities comparable to pymetrozine, thus emerging as novel insecticidal lead compounds. Additionally, compounds 3c (60%), 3e (60%), and 3f (60%) exhibited good larvicidal activities against C. pipiens pallens at 0.5 mg/kg. Further fungicidal activity tests revealed that most derivatives exhibited broad-spectrum fungicidal activities. A total of twelve compounds exhibited better fungicidal activities against cercospora arachidicola hori than carbendazim, and eight compounds exhibited better fungicidal activities against fusarium moniliforme than carbendazim. This work suggests that compound 3e could serve as an insecticidal lead compound for further structural optimization. Full article

Dengue is a mosquito-borne viral disease transmitted by Aedes aegypti, the main vector in the Americas. The lack of effective antiviral treatments, limited vaccine coverage, and the increasing resistance of mosquitoes to conventional insecticides emphasize the need for alternative vector control strategies. Plant-derived larvicides represent a promising and eco-friendly approach. This study characterized the phytochemical profile of Persea americana Mill. (var. Lorena) and evaluated its larvicidal activity against Ae. aegypti (Rockefeller strain). The phytochemical profile was assessed through qualitative screening, UV-Vis spectrophotometry, and UHPLC analysis. Larvicidal activity was evaluated against third-instar larvae of Ae. aegypti (Rockefeller strain) and the median lethal concentration (LC₅₀) values were determined. Preliminary screening of ethanolic extracts revealed the presence of various secondary metabolites of pharmacological relevance, including alkaloids, coumarins, tannins, flavonoids, saponins, triterpenes/sterols, and quinones. UV-Vis spectra displayed distinct absorption patterns, with a prominent peak near 260 nm, consistent with the presence of aromatic compounds. UHPLC profiling revealed high chemical diversity across different plant parts, with 70, 98, 71, and 52 peaks (above 1 × 10⁵ intensity) detected in seed, flower, pulp, and leaf extracts, respectively. Larvicidal bioassays showed significant activity, particularly in the seed extract, with LC₅₀ values (µg/mL) of 3.8 (3.3–4.1) for seeds, 22.4 (21.8–23.9) for flowers, 23.0 (21.5–24.6) for pulp, and 29.7 (28.1–31.2) for leaves. This study highlights the larvicidal potential of ethanolic extracts from P. americana (var. Lorena), with the seed extract exhibiting the highest chemical diversity and bioactivity against Ae. aegypti larvae. The detection of key secondary metabolites, including flavonoids, alkaloids, and saponins, supports the development of an effective, plant-based larvicide for sustainable vector control strategies. Full article

In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease incidence and insecticide resistance (IR) call for a critical appraisal of historical and current control practices. This literature review compiles secondary data produced from 1901 to 2024 obtained from Medline/PubMed, Google Scholar, and governmental notes and reports. Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, microbial larvicides (Bti and Lsp), spinosad, and recently formulations with dual active-ingredient. Ae. aegypti showed widespread resistance to temephos and pyrethroids, decreased susceptibility to pyriproxyfen, and no documented Bti resistance. Anopheles spp. exhibited low to moderate resistance to pyrethroids. Cx. quinquefasciatus resistance is likely influenced by collateral exposure from Aedes control and domestic use. Regarding triatomines and phlebotomines, there was a predominant reliance on pyrethroids; most studies indicate their susceptibility to these compounds. In short, Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. For other species, for which there is no dedicated program for a long period, data on resistance are scarce or nonexistent. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions. Full article

Background/Objectives: Vector-borne diseases like malaria remain a major global health concern, worsened by insecticide resistance in mosquito populations. Quinoline-based compounds have been extensively studied for their pharmacological effects, including antimalarial and larvicidal properties. Modifying quinoline structures with hydrazone groups may enhance their biological activity and physicochemical properties. This study reports the synthesis, structural characterization, and larvicidal testing of a new series of aryl hydrazones (6a–i) derived from 8-trifluoromethyl quinoline. Methods: Compounds 6a–i were prepared via condensation reactions and characterized using ¹H NMR, ¹⁹F-NMR, ¹³C NMR, and HRMS techniques. Their larvicidal activity was tested against Anopheles arabiensis. Single-crystal X-ray diffraction (XRD) was performed on compound 6d to determine its three-dimensional structure. Hirshfeld surface analysis, fingerprint plots, and interaction energy calculations (HF/3-21G) were used to examine intermolecular interactions. Quantum chemical parameters were computed using density functional theory (DFT). Molecular docking studies were performed for the synthesized compounds 6a–i against the target acetylcholinesterase from the malaria vector (6ARY). In silico ADMET properties were also calculated to evaluate the drug-likeness of all the tested compounds. Results: Compound 6a showed the highest larvicidal activity, causing significant mortality in Anopheles arabiensis larvae. Single-crystal XRD analysis of 6d revealed a monoclinic crystal system with space group P2₁/c, stabilized by N–H···N intermolecular hydrogen bonds. Hirshfeld analysis identified H···H (22.0%) and C···H (12.1%) interactions as key contributors to molecular packing. Density functional theory results indicated a favorable HOMO–LUMO energy gap, supporting molecular stability and good electronic distribution. The most active compounds, 6a and 6d, also showed strong binding interactions with the target protein 6ARY and satisfactory ADMET properties. The BOILED-Egg model is a powerful tool for predicting both blood–brain barrier (BBB) and gastrointestinal permeation by calculating the lipophilicity and polarity of the reported compounds 6a–i. Conclusions: The synthesized arylhydrazone derivatives demonstrated promising larvicidal activity. Combined crystallographic and computational studies support their structural stability and suitability for further development as eco-friendly bioactive agents in malaria vector control. Full article

The tick Rhipicephalus sanguineus is the most prevalent ectoparasite in dogs, causing discomfort to the animals and acting as a vector for several pathogens, including the bacterium Ehrlichia canis and the protozoa Babesia canis, Babesia gibsoni, and Hepatozoon canis. Control of this parasite is traditionally carried out with synthetic chemical acaricides. However, due to the increasing number of cases of resistance, phytotherapy has been increasingly investigated as a promising alternative. In this study, the larvicidal activity of the crude ethanolic extract and essential oil obtained from the inflorescences of Achyrocline satureioides was evaluated, whose constituents were identified through phytochemical analyses and gas chromatography. The analyses revealed that the extract is rich in flavonoids, tannins, and saponins, while the essential oil is composed mainly of terpenes. In contact tests with impregnated paper, the extract at 100 mg/mL showed a mortality rate of 32.2% in R. sanguineus larvae with LC₅₀ calculated at 249.62 mg/mL, while the essential oil, at the same concentration, resulted in 56.55% mortality, and the LC₅₀ and LC₉₀ were 119.73 mg/mL and 185.53 mg/mL, respectively. These results indicate that the essential oil of A. satureioides has significant larvicidal activity and has potential for use as an alternative, alone or in combination with other extracts or synthetic acaricides. Full article

Control of Aedes aegypti, the primary vector of arboviruses such as dengue, Zika, and chikungunya, is increasingly difficult due to resistance to synthetic insecticides and environmental concerns. Plant essential oils offer sustainable alternatives with multi-target modes of action and rapid biodegradation. This study evaluated the insecticidal potential of the essential oil of Aniba canelilla (EOANIB), its major constituent 1-Nitro-2-phenylethane (NFTANE), and the derivative 1-Nitro-2-phenylethene (NFTENE) against larvae and adults of A. aegypti. Acetylcholinesterase (AChE) inhibition was quantified using enzymes from Electrophorus electricus, Aedes aegypti and Drosophila melanogaster. Pluronic^® F127 (5% w/v) nanoformulations loaded with EOANIB, NFTANE, or NFTENE at 1.5% or 0.34% (w/v) improved efficacy and stability. Formulations remained stable for 120 to 190 days at 25 to 60 °C. Larvicidal assay at 24 h yielded LC₅₀ values of 86.9 (CI 78.2–94.7) ppm for EOANIB, 84.8 ppm (CI 75.6–92.4) for NFTANE and 10.9 (CI 8.0–14.0) ppm for NFTENE. Against adults, EOANIB achieved an LC₅₀ of 33.9 ppm at 1.5 h. Nanoformulation reduced the EOANIB LC₅₀ by 22.2% after 24 h and 40.1% after 48 h. Toxicity assays evaluated selectivity with Artemia salina (EOANIB LC₅₀: 77.2 ppm) and no mortality in D. melanogaster at 100 ppm. The convergence of efficacy, formulation-enhanced performance, and demonstrated storage stability positions Aniba canelilla as a promising source of bioinsecticide candidates for Aedes aegypti control and supports further development of micellar delivery systems for integrated vector management. Full article

Juniperus is one of the vital genera of the Cupressaceae family; many Juniperus species (juniper) have served as traditional folk medicines. The aims of this study are to analyze its chemical composition and to evaluate the mosquito larvicidal activity of leaf essential oil and its constituents. The constituents of leaf essential oil were analyzed by GC-MS. Leaf essential oil is mainly composed of hydrocarbon monoterpenes and, secondly, oxygenated monoterpenes. Leaf essential oil exhibited good brine shrimp lethality activity, which is highly correlated with larvicidal activity, with the LC₅₀ of 49.89 μg/mL. Leaf essential oil showed a strong mosquito larvicidal activity against two Dengue vector mosquitoes, Aedes aegypti and Ae. albopictus, the LC₅₀ values for both species were lower than 50 μg/mL. Among the major constituents of leaf essential oil, compounds limonene, sabinene, and β-myrcene also exhibited a significant larvicidal effect. Through these investigations, it is expected that leaf essential oil from J. chinensis var. kaizuka and its constituents are of potential use as environmental control chemicals against Dengue vector mosquitoes. Full article