Biopesticides Research Articles

N-acetylglucosamine kinase (BbHxk1) has pleiotropic effects on vegetative growth, cell wall integrity, morphological transition, cuticle infection, and metabolic modulation in the biological pesticide Beauveria bassiana

Beauveria bassiana is a popular and eco-friendly biopesticide. During its pathogen-pest interaction, both N-acetylglucosamine (GlcNAc) catabolism and anabolism are crucial for nutrient supply and cell-wall construction. The initiation of GlcNAc metabolism relies on the catalysis of GlcNAc kinase, which has been extensively studied in the human pathogen Candida albicans. However, the physiological function of GlcNAc kinase remains poorly understood in entomopathogenic fungi. In the present study, a GlcNAc kinase homolog was identified and designated as BbHxk1 in B. bassiana. Deletion of BbHxk1 resulted in viable but reduced vegetative growth on various carbon sources. ΔBbHxk1 mutants displayed severe defects in cell wall integrity, making them more susceptible to cell wall stress cues. Furthermore, the absence of BbHxk1 resulted in an increase in conidial yield and blastospore production, and a faster rate of germination and filamentation, potentially attributed to higher intracellular ATP levels. BbHxk1 deficiency led to a reduction in the activities of cuticle-degrading enzymes, which might contribute to the attenuated pathogenicity specifically through cuticle penetration rather than hemocoel infection towards Galleria mellonella larvae. Being different from C. albicans Hxk1, which facultatively acts as a catalyzing enzyme and transcriptional regulator, BbHxk1 primarily acts as a catalyzing enzyme and metabolic regulator. The altered metabolomic profiling correlated with the phenotypic defects in ΔBbHxk1 mutants, further implicating a potential metabolism-dependent mechanism of BbHxk1 in mediating physiologies of B. bassiana. These findings not only unveil a novel role for GlcNAc kinase in B. bassiana, but also provide a solid theoretical basis to guide metabolic reprogramming in order to maintain or even enhance the efficiency of fungi for practical applications.

Giants' cooperation: a draft genome of the giant ciliate Muniziella cunhai suggests its ecological role in the capybara's digestive metabolism.

Several hundred ciliate species live in animals' guts as a part of their microbiome. Among them, Muniziella cunhai (Trichostomatia, Pycnotrichidae), the largest described ciliate, is found exclusively associated with Hydrochoerus hydrochaeris (capybara), the largest known rodent reaching up to 90 kg. Here, we present the sequence, structural and functional annotation of this giant microeukaryote macronuclear genome and discuss its phylogenetic placement. The 85 Mb genome is highly AT rich (GC content 25.71 %) and encodes a total of 11 397 protein-coding genes, of which 2793 could have their functions predicted with automated functional assignments. Functional annotation showed that M. cunhai can digest recalcitrant structural carbohydrates, non-structural carbohydrates, and microbial cell walls, suggesting a role in diet metabolization and in microbial population control in the capybara's intestine. Moreover, the phylogenetic placement of M. cunhai provides insights on the origins of gigantism in the subclass Trichostomatia.

The Public Health Leader Who Brought Antisepsis to William Halsted.

William Halsted wrote to aging surgeon, Stephen Smith, in 1919, that he remembered the lessons Smith had taught him, "when I walked with you through the wards of Bellevue Hospital." Smith was an early advocate of Joseph Lister's antiseptic method, and because of his public health work, he was also an early advocate of environmental hygiene and microbial control based on the unproved germ theory. While Lister's work at the time emphasized germ-killing around the operative site with carbolic acid (antisepsis), Smith adopted and encouraged surgical practices at Bellevue that would be hallmarks of the germ-preventing (asepsis) surgical approach that fully developed after German bacteriologic discoveries in the mid-1880s, and with which Halsted is historically identified. Some physicians and historians have emphasized temporal and conceptual differences between Lister's antisepsis and German asepsis, but Smith and Halsted's experiences argue that surgical asepsis was the evolutionary outcome of germ theory-based surgical changes that began well before scientific proof arrived.

Enhancing microbial control in poultry processing: A comprehensive study on carcass washing systems

AbstractIn the poultry industry, the evisceration stage often sees the highest microbial load on chicken carcasses. While manual trimming has traditionally been employed to remove gastrointestinal contamination, Brazilian legislation allows the use of a carcass washing system as an alternative. This study aimed to establish and validate a protocol for the use of a chicken carcass washing system as a replacement for manual trimming in a major poultry processing facility in southern Brazil. The methodology followed international standards for microbial analysis such as total mesophilic counts and Enterobacteriaceae. Comparing contamination levels before and after treatments, significant reductions are seen. Manual trimming reduced contamination by 39.43% (gastric), 53% (fecal), and 50% (biliary). Washing achieved greater reductions, with a 96.37% drop in gastric contamination and complete elimination (100%) of fecal contamination. These results met statistical significance. Both procedures reduced contamination levels. Manual trimming maintained 50% of samples below the mean value without exceeding upper control limits (UCL). Washing increased the percentage of samples below the mean value from 46% to 54%, demonstrating its superior efficiency. For Enterobacteriaceae, trimming maintained 44% of samples below the mean value, and washing increased it from 46% to 48%. In conclusion, the carcass washing system effectively removes visible gastrointestinal contents, meeting regulatory standards and receiving authorization from the Federal Inspection Service for use in the facility.

Optimization of acetic acid – infused insecticide from avocado (persea americana) seed extract using microwave – assisted extraction method

Abstract Insecticides are widely used in households to control and manage pest populations. Biological insecticides are a more sustainable alternative, but they are often less effective. This study evaluated the effectiveness of avocado seed oil extract with added acetic acid as a bio-insecticide against Aedes aegypti mosquitoes. The researchers used microwave-assisted extraction to obtain the avocado seed oil. Avocado oil and acetic acid were formulated in different volume concentrations: 10%, 30%, 50%, 70%, and 90% (v/v) avocado seed oil extract-infused acetic acid. Assessment of its effectiveness is performed by directly spraying it on Aedes aegypti mosquitoes in a 70x70x70 cm glass cylinder setup and conducting knockdown and mortality tests. The avocado seed oil insecticide showed significant knockdown effectiveness (p= 2.07E-7, α= 0.95) against Aedes aegypti mosquitoes compared to both the positive control (Neem Oil) and negative control (acetic acid). At 1 mL application, all the concentrations have significant differences (p= 0.0044, α= 0.95). The 50% and 90% concentration show the highest efficacy, showing no significant difference (p-value= 0.0527, α= 0.95), the % Knockdown is 25.00% and 20.00%, respectively, while 30% is the lowest at 13.33% within 60 minutes. However, none of the test samples reached 50% knockdown in 60 minutes. At a 3 mL rate, all concentrations resulted in 100% mortality, and the 50% concentration was the fastest in 6 minutes but had no significant difference (p= 0.9746, α= 0.95) with 90% concentration at 10 minutes. All concentrations yield higher efficacy compared to the positive control in both 1 mL and 3 mL rates. In the 1 mL and 3 mL tests, there were no recorded instances of mortality in the pure acetic acid sample. Based on the results, the optimum product among all the formulated concentrations is 50% (v/v) avocado seed oil extract-infused acetic acid having a significant difference (p=2.83E-13, α= 0.95).

Microbial agents for the control of ticks Rhipicephalus microplus.

Ticks are ectoparasites responsible for the transmission of various pathogens to vertebrates. They represent one of the major threats to livestock production worldwide due to their impact on the health, production and welfare of livestock destined for human consumption. The development of resistance to the main families of ixodicides used for their control has led to the search for new alternatives, where microbial control is an option. The use of microbial control agents against the tick Rhipicephalus microplus is reviewed in this paper. Bacteria such as Bacillus thuringiensis, Serratia marcescens and Staphylococcus spp. the nematodes Steinernema spp. and Heterorhabditis spp. as well as the fungi Metarhizium anisopliae and Beauveria bassiana are the most studied organisms for use as biological control agents against ticks. Laboratory, stable and field trials with free-living and parasitised ticks have shown that microbial agents can control both susceptible and ixodicide-resistant tick populations. However, multidisciplinary studies using novel tools like genomics, transcriptomics and proteomics should be carried out to understand the virulence factors which microbial agents use to induce pathogenesis and virulence in ticks. In addition, applied research will be carried out with the aim of improving techniques for large-scale application, as well as the improvement of cultivation, storage, formulation and application methods.

Exploring Efficacy and Safety: Comparative Evaluation of Different Irrigation Solutions in Root Canal Therapy at a Tertiary Care Setting.

In order to completely remove bacteria and debris from the root canal system, root canal treatment (RCT) calls for efficient irrigation methods. There is still a lack of research on the relative safety and efficacy of various irrigation systems in tertiary care settings. Patients receiving RCT at a tertiary care endodontic clinic were included in a prospective comparison research of 150 subjects. One of four irrigation solutions-sodium hypochlorite, chlorhexidine, ethylenediaminetetraacetic acid (EDTA), or a combination of the three-was given to patients at random. Following surgery, microbial decrease and patient-reported pain levels were evaluated. The analysis showed that there were significant differences (P < 0.05) in microbial decrease between the irrigation solution groups. EDTA, sodium hypochlorite, and chlorhexidine were the next three groups with the biggest mean log decrease in microbial counts, after the combination group. Nonetheless, there were no appreciable variations in the groups' patient-reported pain levels (P > 0.05). Our results imply that microbial reduction in RCT is highly influenced by the irrigation solution selection. Without having an impact on the pain sensations reported by the patients, the combination of irrigation solutions showed higher efficacy in microbial control. These findings highlight how crucial it is to choose an irrigation solution carefully in order to maximize endodontic outcomes in tertiary care settings.

SWOT analysis of risk prevention and control of microorganism pollution in shopping malls and supermarkets

To understand the status and problems of microbial pollution in shopping malls and supermarkets in China. Microbial pollution in shopping malls and supermarkets was assessed by literature search, key information extraction and analysis. The strengths, weaknesses, opportunities and threats(SWOT) of risk control of pathogenic microorganisms in shopping malls and supermarkets were analyzed by SWOT analysis. Common bacteria in the indoor air of shopping malls and supermarkets included staphylococcus and Bacillus, and common fungi include Aspergillus and Penicillium. The bacteria detected in dust samples, escalator surfaces and floor surfaces were mainly Proteobacteria and Actinomyces. The complete public places laws and regulations, standards and health supervision system were the advantages of the risk prevention and control countermeasures of microbial contamination in shopping malls and supermarkets. At the same time, it also had the disadvantages of incomplete microbial-related indexes in the premises, and insufficiently detailed countermeasures for prevention and control in the premises. There were opportunities for multi-sectoral participation and post-licensing risk prevention, and it was also facing challenges brought by many factors affecting the health microenviroment and over-disinfection. The main sites for microbial risk prevention and control in superstore-type public places included high-frequency contact areas, key public supplies and utensils, indoor air, etc. , which could be prevented and controlled through a variety of measures such as controlling the release of the source, dilution and reduction, disinfection and denaturation, etc. , and exploring a comprehensive prevention and control system that involves the autonomy of the organization, industry self-regulation, collaboration of multi-government departments, and participation of the whole society.

Valorization of the Caragana waste via two-stage bioaugmentation: Optimizing nutrition composition, palatability, and microbial contaminant control

Caragana korshinskii kom. (CKK) waste, a common forestry byproduct in northwest of China, presents challenges in its transformation into alternative ruminant feed due to its initial nutritional limitations and unappealing palatability. Conventional strategies, such as ensiling and fungal-based solid-state fermentation (SSF) cannot effectively address this issue in practice. Herein, a two-stage bioaugmentation (TBA) process was devised, leveraging the benefits of ensiling and SSF. During the anaerobic ensiling phase, CKK waste was inoculated with Lactiplantibacillus plantarum LP1, effectively suppressing potential animal pathogens such as Aspergillus and Nocardiopsis while enriching the material with potential probiotics like Pediococcus and Lactiplantibacillus, reaching an abundance of 95.7%. In the subsequent aerobic SSF stage, the ensiled CKK underwent inoculation with the white-rot fungus Irpex lacteus F17, which became enriched to 87.9%. Comprehensive multi-omics analysis identified Irpex as the key taxon, possessing an extensive redox enzyme system that led to the improvement in nutrient composition, reduction of astringent phenolic substances, and mitigation of mycotoxins. As a result, the crude protein content of the CKK increased by 39.2%, while lignin, total phenolic substances, and tannic acid content decreased by 24.4%, 52.2%, and 51.4%, respectively. The mycotoxin levels, including aflatoxin B1, zearalenone, and vomitoxin, were rendered negligible, confirming the safety. Overall, this study demonstrates the TBA strategy can successfully transform challenging and unpalatable CKK waste into a nutrient-enriched and safe mycelium-based bioproduct, thereby enabling the valorization of a previously underutilized forestry resource as a promising alternative feed.

Enriched advanced platelet-rich fibrin plus gold nanoparticles against Enterococcus faecalis for its potential use in revascularization for necrotic immature permanent teeth.

Regenerative endodontic procedures allow reinforcement of root canal wall and continuation of root development, opening new therapeutic possibilities. The root canal system of infected teeth is colonized by a variety of microorganisms, which hinder the regenerative process, leading to treatment failure if not adequately addressed, thereby requiring careful attention to microbial control. The aim of the study was to assess the antimicrobial activity of advanced platelet-rich fibrin (A-PRF) and gold nanoparticles (AuNps) against Enterococcus faecalis. Intravenous blood (5-6 ml) was drawn from four healthy individuals, and A-PRF was prepared through centrifugation at 1500 revolutions per minute (rpm) for 14 min. A-PRF was doped with 3 µl of AuNps and centrifuged at 1000 rpm for 1 min. Antimicrobial activity was assessed using disk diffusion; inhibition zones were measured. For minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), A-PRF + AuNps were added to the microbial broth at varying concentrations to determine growth inhibition and microbial death. Disk diffusion assays revealed significant antibacterial effects against E. faecalis. Norfloxacin displayed the highest mean zone of inhibition (20.33 ± 1.53 mm), followed by the Test group (A-PRF + AuNPs) (19.33 ± 0.58 mm). Multiple comparisons indicated significant differences (P < 0.001). MIC of A-PRF + AuNPs against E. faecalis was 0.031 mg/ml, with MBC at 0.015 mg/ml. The addition of AuNPs to A-PRF offers the potential for sustained growth factor release while maintaining the sterility of the canal, leading to successful revitalization and regeneration. The combined use of A-PRF + AuNps shows promise for enhancing revascularization in necrotic immature permanent teeth.

Efficacy of bio pesticides on growth, yield and red ant damage to potato

Efficacy of bio pesticides on growth, yield and red ant damage to potato

Microbial Pesticides and Inoculants Production - A Promising Technology to Chemical Pesticides

Microbial Pesticides and Inoculants Production - A Promising Technology to Chemical Pesticides

Effects of Essential Oils on Biological Characteristics and Potential Molecular Targets in Spodoptera frugiperda.

Spodoptera frugiperda control methods have proved to be inefficient, which justifies the search for new control measures. In this search for botanical insecticides for controlling S. frugiperda, the following were evaluated: (i) the toxicity of essential oils (EOs) from Cinnamodendron dinisii, Eugenia uniflora, and Melaleuca armillaris; (ii) the effect of EOs on life table parameters against S. frugiperda; (iii) the chemical characterization of EOs; and (iv) the in silico interaction of the chemical constituents present in the three EOs with the molecular targets of S. frugiperda. The EO from E. uniflora had the lowest LD50 (1.19 µg of EO/caterpillar). The major compounds bicyclogermacrene (18.64%) in C. dinisii and terpinolene (57.75%) in M. armillaris are highly predicted to interact with the octopamine receptor (OctpR). The compound 1,8-cineole (21.81%) in M. armillaris interacts mainly with a tolerant methoprene receptor (MET) and curzerene (41.22%) in E. uniflora, which acts on the OctpR receptor. Minor compounds, such as nerolidol in C. dinisii and β-elemene in E. uniflora, are highly ranked for multiple targets: AChE, MET, OctpR, and 5-HT1. It was concluded that the EO from E. uniflora negatively affects several biological parameters of S. frugiperda development and is promising as an active ingredient in formulations for controlling this insect pest.

Complete photodynamic inactivation of Pseudomonas aeruginosa biofilm with use of potassium iodide and its comparison with enzymatic pretreatment

Pseudomonas aeruginosa, a gram-negative bacterium, accounts for 7% of all hospital-acquired infections. Despite advances in medicine and antibiotic therapy, P. aeruginosa infection still results in high mortality rates of up to 62% in certain patient groups. This bacteria is also known to form biofilms, that are 10 to 1000 times more resistant to antibiotics compared to their free-floating counterparts. Photodynamic Inactivation (PDI) has been proved to be an effective antimicrobial technique for microbial control. This method involves the incubation of the pathogen with a photosensitizer (PS), then, a light at appropriated wavelength is applied, leading to the production of reactive oxygen species that are toxic to the microbial cells. Studies have focused on strategies to enhance the PDI efficacy, such as a pre-treatment with enzymes to degrade the biofilm matrix and/or an addition of inorganic salts to the PS. The aim of the present study is to evaluate the effectiveness of PDI against P. aeruginosa biofilm in association with the application of the enzymes prior to PDI (enzymatic pre-treatment) or the addition of potassium iodide (KI) to the photosensitizer solution, to increase the inactivation effectiveness of the treatment. First, a range of enzymes and PSs were tested, and the best protocols for combined treatments were selected. The results showed that the use of enzymes as a pre-treatment was effective to reduce the total biomass, however, when associated with PDI, mild bacterial reductions were obtained. Then, the use of KI in association with the PS was evaluated and the results showed that, PDI mediated by methylene blue (MB) in the presence of KI was able to completely eradicate the biofilm. However, when the PDI was performed with curcumin and KI, no additive reduction was observed. In conclusion, out of all strategies evaluated in the present study, the most promising strategy to improve PDI against P. aeruginosa biofilm was the use of KI in association with MB, resulting in eradication with 108 log bacterial inactivation.

Generic viability qPCR for monitoring shelf life of microbial biological control agents coated on seeds based on the nucleic acid intercalating dyes EMA and PMAxx

Biological control of seedborne pathogens and soilborne seedling pathogens through antagonists applied on seeds is an alternative to chemical seed treatments. Information on the viability of inocula on treated seeds is essential for any development and use of beneficial fungi or bacteria on seeds. Generic fungal and bacterial qPCR assays were combined with the nucleic acid intercalating dyes ethidium monoazide (EMA) and propidium monoazide (PMAxx) for the quantification of viable cells of fungi and bacteria on seeds. The applied protocols for generic fungal viability qPCR (v-qPCR) in combination with EMA and PMAxx and for generic bacterial v-qPCR in combination with PMAxx allowed the viability quantification of fungal and bacterial isolates representing a broad range of species with the exception of fungal species with highly melanized conidia. A first application of v-qPCR to coated seeds of onion and spinach indicated a differential plant species effect on survival of a coated fungus and a yeast with a generally better survival on seeds of spinach compared to seeds of onions and a similar good survival of the bacterium L. enzymogenes 3.1T8 on both seed types. The v-qPCR protocols can be applied in screening assays aiming at the selection of new antagonists with higher survival potentials and the development of new seed processing technologies compatible with coated antagonists.

Efficacy of different pesticides in suppressing yellow stem borer in spring rice (Oryza sativa) in Ratuwamai, Morang, Nepal

Rice, a staple food for over half the global population, is crucial for food security, economic stability, and cultural significance. Its production, however, is threatened by pests like the Yellow Stem Borer (YSB), which causes substantial yield losses, especially in rice-dominant regions like Nepal. This study focuses on evaluating the effectiveness of biological, botanical, and chemical pesticides against YSB in spring rice crops of Ratuwamai, Morang, Nepal. For this, we apply biological methods/pathogens like Bacillus thuringiensis, to target YSB; botanical pesticides, derived from plants like Azadirachtin and Mugworth, act as repellents; while chemical pesticides such as Cypermethrin, Chlorpyriphos and Cartap Hydrochloride offer rapid control but come with environmental risks. Among those six pesticides used, the present findings revealed that chlorpyriphos 20% EC have minimum mean dead heart with 4.92% and cypermethrin 10% EC have minimum mean white ear head with 2.44% respectively after application of first and second dose of treatments respectively. Likewise, most plant yield attributes were superior where chlorpyriphos was used. Though bacillus and azadirachtin reduced the dead heart and white ear head symptoms, they couldn’t give good yield than that of chemical pesticides. Thence, through our research we investigated the impacts of different biological, botanical and chemical pesticides in controlling YSB population densities, and influencing yield and yield attributing characters from the field experiment.

The Potential of Forest Betel Weed as Raw Materials for Botanical Pesticides in West Sumatra

Forest betel (Piper aduncum) includes weed plants from the Piperaceae family that can be used as the main ingredient in the manufacture of environmentally friendly pest control technology, also known as botanical pesticides. Botanical pesticides from P. aduncum have the active compound dillapiol, which can control pests in various plants, especially horticulture. Commercialization of botanical pesticides needs to be done because the product meets the standards for pest control and is available in sufficient quantities on the market. The partnership was initiated by involving local communities as providers of raw materials. Surian area, Solok Regency, West Sumatra, Indonesia, has an area where P. aduncum plants dominate, so it has the potential to provide raw materials. Socialization activities about the potential of forest betel fruit or P. aduncum were given to prospective partner communities. Furthermore, training activities on handling P. aduncum fruit were also provided so that partners had sufficient knowledge and skills to proceed. At the same time, an analysis of P. aduncum fruit extract from the Surian area was also carried out. Sampling was carried out in the Surian area, and then the material was sorted, dried, refined, sieved, maserase, and extracted. Identification of dillapiol content was carried out using GC-MS. The analysis results showed that P. aduncum fruit extract was known to have an average yield of 0.1% with a dillapiol content of 12.23% at a retention time of 19.925 minutes.

Characterization of free and encapsulated cinnamon and clove essential oils for enhancing fresh sausage quality: A natural substitute for synthetic preservatives

This study aims to evaluate the properties of essential oils (EOs) from cinnamon (Cinnamomum cassia) and clove (Eugenia caryophyllus). Mixtures of cinnamon and clove EOs at ratios of 75:25, 50:50, and 25:75 were encapsulated and applied in fresh sausage. The research includes a kinetic examination of active component release and preservation parameter monitoring. Clove EO showed superior antioxidant activity (0.039 mg/mL), while cinamon oil exhibited promising bacterial inhibition (minimum inhibitory concentration lower 1.5). Combinations of cinnamon and clove EOs demonstrated synergistic antioxidant and antimicrobial effects. Encapsulation efficiency for the 25:75 cinnamon and clove oil mixture reached 89.4%, with 80.9% EO retention. The microencapsulated mixture displayed commendable antimicrobial and antioxidant activities, slowing compound release (>50% after 15 days). The encapsulated EOs (25:75) showed comparable results in lipid oxidation (0.194 mg malonaldehyde/kg) and microbial control to traditional curing salt, suggesting substitution potential. By encapsulating cinnamon and clove essential oils and evaluating their efficacy in fresh sausages, this research demonstrates their potential to enhance the safety and quality of meat products while addressing consumer demand for healthier and more natural food options.

Green purification of Acmella oleracea extract by wiped-film short path molecular distillation boosts the insecticidal activity on mosquito larvae

The development of insecticide resistance by mosquito vectors highlighted an urgent need for effective and sustainable botanical insecticides. Acmella oleracea R.K. Jansen (Asteraceae)-derived extracts and the major constituents N-alkylamides have already demonstrated their potential as insecticidal and acaricidal agents. Nowadays, the development of scalable green extraction and purification processes in the manufacture of biopesticides is a topic of great interest. In this context, supercritical fluid extraction and wiped-film short path molecular (WSM) distillation techniques were combined for the first time to obtain an eco-friendly N-alkylamides-enriched fraction (AEF) from A. oleracea. This was characterized by a notably higher content of spilanthol and N-alkylamides than the supercritical fluid extract (SFE), as determined by HPLC-DAD-MS analysis. The AEF also contained free fatty acids (e.g., palmitic, linoleic, and linolenic acids) as revealed by GC-FID analysis. The mosquito larvicidal activity of SFE, AEF, and pure spilanthol was assessed against 3rd instar larvae of Aedes albopictus Skuse, Anopheles stephensi Liston, and An. gambiae Giles. Results showed that AEF exhibited an insecticidal efficacy comparable with that of spilanthol, and higher than that of SFE. These products were tested against human keratinocytes (HaCaT) confirming their dermal safety. The present study paves the way for the utilization of WSM distillation in the agrochemical industry for the manufacture of botanical insecticides. Indeed, this technique allows to avoid the use of organic solvents related to conventional extraction and spilanthol isolation procedures and gives a product devoid of undesired pigments appealing to other industrial application as well.

In-Depth Structural Simplification of Celangulin V: Design, Synthesis, and Biological Activity.

Celangulin V is a novel botanical insecticide with significant bioactivity and a unique molecular target, but its complex polyol ester structure hinders its broader application in agriculture. To discover new analogues of celangulin V with a simpler structure and enhanced biological activities, we initiated a research project aimed at simplifying its structure and assessing insecticidal efficacy. In this study, a series of novel 1-tetralone derivatives were designed via a structure-based rational design approach and synthesized by a facile method. The biological activities of the target compounds were determined against Mythimna separata (M. separata), Plutella xylostella, and Rhopalosiphum padi. The results revealed that most of the synthesized compounds exhibited superior activities compared to celangulin V. Remarkably, the insecticidal activity of compound 6.16 demonstrated 102-fold greater stomach toxicity than celangulin V against M. separata. In addition, certain compounds showed significant contact toxicity against M. separata, a finding not reported previously in the structural optimization studies of celangulin V. Molecular docking analysis illustrated that the binding pocket of compound 6.16 with the H subunit of V-ATPase was the same as celangulin V. This study presents novel insights into the structural optimization of botanical pesticides.