Actions of quinolizidine alkaloids on Periplaneta americana nicotinic acetylcholine receptors

Natural 3,4-dihydro-2(1h)-quinolinones- Part II: animal, bacterial, and fungal sources

While natural products have undoubtedly played a pivotal role in drug discovery, their potential as lead compounds has been hindered by challenges such as limited accessibility and complex synthesis processes. At the core of numerous natural and synthetic compounds, each exhibiting remarkable biological traits, lies the foundational structure of 3,4-dihydro-2(1H)-quinolinone, also recognised as 2-oxo-tetrahydroquinoline (2 O-THQ). This article extensively examines the occurrence of 2 O-THQ alkaloids across diverse organisms including animals, fungi, and bacteria, exploring their capacity to serve as a source for innovative bioactive natural products. Despite the undeniable significance of these compounds, the existing body of review literature has yet to provide comprehensive coverage, underscoring the pivotal contribution of this present article in investigating their prevalence in nature.

"One-Pot" Method Preparation of Dendritic Mesoporous Silica-Loaded Matrine Nanopesticide for Noninvasive Administration Control of Monochamus alternatus: The Vector Insect of Bursapherenchus xylophophilus

Monochamus alternatus is an important stem-boring pest in forestry. However, the complex living environment of Monochamus alternatus creates a natural barrier to chemical control, resulting in a very limited control effect by traditional insecticidal pesticides. In this study, a stable pesticide dendritic mesoporous silica-loaded matrine nanopesticide (MAT@DMSNs) was designed by encapsulating the plant-derived pesticide matrine (MAT) in dendritic mesoporous silica nanoparticles (DMSNs). The results showed that MAT@DMSNs, sustainable nanobiopesticides with high drug loading capacity (80%) were successfully constructed. The release efficiency of DMSNs at alkaline pH was slightly higher than that at acidic pH, and the cumulative release rate of MAT was about 60% within 25 days. In addition, the study on the toxicity mechanism of MAT@DMSNs showed MAT@DMSNs were more effective than MAT and MAT (0.3% aqueous solutions) in touch and stomach toxicity, which might be closely related to their good dispersibility and permeability. Furthermore, MAT@DMSNs are also involved in water transport in trees, which can further transport the plant-derived insecticides to the target site and improve its insecticidal effect. Meanwhile, in addition, the use of essential oil bark penetrants in combination with MAT@DMSNs effectively avoids the physical damage to pines caused by traditional trunk injections and the development of new pests and diseases induced by the traditional trunk injection method, which provides a new idea for the application of biopesticides in the control of stem-boring pests in forestry.

Cytisine: State of the art in pharmacological activities and pharmacokinetics

Cytisine is a naturally occurring bioactive compound, an alkaloid mainly isolated from legume plants. In recent years, various biological activities of cytisine have been explored, showing certain effects in smoking cessation, reducing drinking behavior, anti-tumor, cardiovascular protection, blood sugar regulation, neuroprotection, osteoporosis prevention and treatment, etc. At the same time, cytisine has the advantages of high efficiency, safety, and low cost, has broad development prospects, and is a drug of great application value. However, a summary of cytisine's biological activities is currently lacking. Therefore, this paper summarizes the pharmacological action, mechanism, and pharmacokinetics of cytisine by referring to numerous databases, and analyzes the new and core targets of cytisine with the help of computer simulation technology, to provide reference for doctors.

Bioactive compounds from Retama raetam (Forssk.) Webb & Berthel. and their insecticidal activity against cotton pests Aphis gosspyii and Amrasca biguttula

Cotton aphids, Aphis gosspyii and cotton jassids, Amrasca biguttula are destructive piercing sucking pests to many strategic crops, especially cotton, not only in Egypt but also all over the world. Using synthetic pesticides to control these pests led to several deleterious impacts. Natural pesticides can be used as a harmless alternative. Nine compounds were isolated from different fractions of Retama raetam using chromatographic techniques and identified by spectroscopic methods as eugenol (1), alpinumisoflavone (2), licoflavone C (3), ephedroidin (4), anagyrine (5), spartiene (6), genistein-8β-C-glucoside (7), isoprunetin (8) and isoprunetin 7-O-β-D-glucopyranoside (9). The methanol crude extract and its fractions (hexane, chloroform, ethyl acetate and butanol), as well as the isolated compounds were examined against A. gosspyii and A. biguttula as insecticides. The results showed that chloroform fraction was the most potent fraction against A. gosspyii and A. biguttula, with LC50 values of 65.66 and 64.43 ppm, respectively. As well, compounds 1, 5 and 6 were found to be more active, with LC50 values of 69.84, 25.49 and 27.22 ppm for A. gosspyii and 65.17, 24.07 and 24.78 ppm for A. biguttula, respectively. The most potent compounds (1, 5 and 6) exhibited AChE inhibition toward A. gosspyii compared with the control. So, it can be concluded that the isolated compounds eugenol 1, anagyrine 5 and spartiene 6 are the active principles due to their capability to inhibit AchE activity.

Assessment of cytisine as an insecticide candidate for Hyphantria cunea management: Toxicological, biochemical, and control potential insights

In the present study, the toxicological effects of cytisine on the H. cunea larvae were investigated, and the potential of cytisine as a botanical insecticide through field simulation experiments was evaluated. The results showed that cytisine treatment (0.25-2.5%) exerted significant biotoxic effects on the H. cunea larvae, including diminished weight, disruption of both positive (HcCKS1, HcPLK, HcCCNA) and negative (HcGADD and HcCDKN) regulatory genes associated with larval growth, increased mortality, and heightened oxidative damage (H2O2 and MDA). Cytisine treatment significantly reduced glucose content and inhibited the expression of key rate-limiting enzyme genes (HcPFK, HcPK, HcHK1, HcCS, and HcIDH2) within glycolysis and the tricarboxylic acid cycle pathways. Under cytisine treatment, detoxification enzyme activities (CarE and GST) and expression of detoxification genes (HcCarE1, HcCarE2, HcCarE3, HcGST1, and HcGST3) were inhibited in H. cunea larvae. An increased contents of SOD, CAT, ASA and T-AOC, as well as expression of antioxidant enzyme genes HcSOD1 and HcCAT2, was found in cytisine-treated H. cunea larvae. Simultaneously, this is accompanied by a significant reduction in the expression of four antioxidant enzyme genes (e.g., HcPOD1 and HcPOD2). In the field experiment, a cytisine aqueous solution (25 g/L) with pre-sprayed and directly sprayed ways demonstrated potent insecticidal activity against H. cunea larvae, achieving a mortality rate of 53.75% and 100% at 24 h, respectively. Taken together, cytisine has significantly weight inhibition and lethal toxicity on the H. cunea larvae, and can be developed as a botanical insecticide for H. cunea control.

Ormosianines A-P, Structurally Diverse Quinolizidine Alkaloids with AChE Inhibitory Effects from Ormosia yunnanensis

Sixteen new quinolizidine alkaloids (QAs), named ormosianines A-P (1-16), and 18 known congeners (17-34) were isolated from the stems and leaves of Ormosia yunnanensis. The structures were elucidated based on spectroscopic analyses and electron circular dichroism (ECD) calculations. Structurally, ormosianines A (1) and B (2) are the first examples of cytisine and Ormosia-type alkaloids with the cleavage of the piperidine ring. Results of the acetylcholinesterase (AChE) inhibitory assay revealed that the pentacycline Ormosia-type QAs, including 1, 16, 24, and 27-29, are good AChE inhibitors. Ormosianine A (1) exhibited more potent AChE inhibitory activity with an IC50 value of 1.55 μM. Molecular docking revealed that 1 might bind to the protein 1DX4, forming two hydrogen bonds with residues SER-238 and HIS-480.

Discovery of 1,2,4-Oxadiazole Derivatives Containing Haloalkyl as Potential Acetylcholine Receptor Nematicides

Plant-parasitic nematodes pose a serious threat to crops and cause substantial financial losses due to control difficulties. Tioxazafen (3-phenyl-5-thiophen-2-yl-1,2,4-oxadiazole) is a novel broad-spectrum nematicide developed by the Monsanto Company, which shows good prevention effects on many kinds of nematodes. To discover compounds with high nematocidal activities, 48 derivatives of 1,2,4-oxadiazole were obtained by introducing haloalkyl at the 5-position of tioxazafen, and their nematocidal activities were systematically evaluated. The bioassays revealed that most of 1,2,4-oxadiazole derivatives showed remarkable nematocidal activities against Bursaphelenchus xylophilus, Aphelenchoides besseyi, and Ditylenchus dipsaci. Notably, compound A1 showed excellent nematocidal activity against B. xylophilus with LC50 values of 2.4 μg/mL, which was superior to that of avermectin (335.5 μg/mL), tioxazafen (>300 μg/mL), and fosthiazate (436.9 μg/mL). The transcriptome and enzyme activity results indicate that the nematocidal activity of compound A1 was mainly related to the compound which affected the acetylcholine receptor of B. xylophilus.

Synthesis of Halopyrazole Matrine Derivatives and Their Insecticidal and Fungicidal Activities

Matrine is a traditional botanical pesticide with a broad-spectrum biological activity that is widely applied in agriculture. Halopyrazole groups are successfully introduced to the C13 of matrine to synthesize eight new derivatives with a yield of 78–87%. The insecticidal activity results show that the introduction of halopyrazole groups can significantly improve the insecticidal activity of matrine on Plutella xylostella, Mythimna separata and Spodoptera frugiperda with a corrected mortality rate of 100%, which is 25–65% higher than matrine. The fungicidal activity results indicate that derivatives have a high inhibitory effect on Ceratobasidium cornigerum, Cibberella sanbinetti, Gibberrlla zeae and Collectot tichum gloeosporioides. Thereinto, 4-Cl-Pyr-Mat has the best result, with an inhibition rate of 23–33% higher than that of matrine. Therefore, the introduction of halogenated pyrazole groups can improve the agricultural activity of matrine.

Design, Synthesis, and Insecticidal Activity of Novel Pyrido[1, 2-a]pyrimidinone Mesoionic Compounds Containing an Indole Moiety as Potential Acetylcholine Receptor Insecticides

In this study, a series of novel mesoionic pyrido[1,2-a]pyrimidinone compounds containing a natural skeleton indole were designed and synthesized, and the insecticidal activities of the target compounds were tested. The results showed that the target compounds had good to excellent insecticidal activities against white-backed planthoppers (Sogatella furcifera) and bean aphids (Aphis craccivora). Among them, compound 7 showed outstanding insecticidal activities against both S. furcifera and A. craccivora, with LC₅₀ values of 0.86 and 0.85 μg/mL, respectively. The insecticidal activity against bean aphids (A. craccivora) was superior to that of triflumezopyrim (LC₅₀ = 3.67 μg/mL). Proteomics and quantitative real-time polymerase chain reaction (qRT-PCR) results revealed that compound 7 may interact with α1 and α7 nAChR subunits of S. furcifera. The results of enzyme activities indicated that compound 7 was an inhibitor of AChE in S. furcifera. This study provides new ideas for the discovery of new mesoionic pyrido[1,2-a]pyrimidinone insecticides.

Research Progress on the Natural Product Aloperine and Its Derivatives

In this review, an effort towards the presentation of an all-around account of the recent progress on the natural product, aloperine is made, and the antivirus structure-activity relationship of its derivatives is also summarized comprehensively. In addition, the principal pharmacological effects and corresponding molecular mechanisms of aloperine are discussed. Some new modification directions of aloperine are given in the end, which might be brief guidance for further investigations on the natural product aloperine.

Synergistic Interaction between the Entomopathogenic Fungus Akanthomyces attenuatus (Zare & Gams) and the Botanical Insecticide Matrine against Megalurothrips usitatus (Bagrall)

The excessive use of synthetic chemicals for Megalurothrips usitatus (Bagrall) management has resulted in the development of insecticide resistance as well as adverse effects to the natural ecosystem. This has driven the need to develop alternative pest control strategies. This study reports a synergistic interaction between the entomopathogenic fungus Akanthomyces attenuatus (Zare & Gams) and the botanical insecticide matrine against M. usitatus. The results revealed that the germination rate and colony growth of A. attenuatus were inhibited by higher matrine concentrations. Percentage mortalities of M. usitatus following application of A. attenuatus and matrine showed a dose mortality effect. After five days of treatment, all concentrations of matrine combined with different concentrations of A. attenuatus, except one combination (matrine 0.25 mg/mL + 1 × 10⁷ conidia/mL), showed synergistic effect. The activities of acetylcholinesterase and antioxidant enzymes (superoxide dismutase, catalase and peroxidase) in M. usitatus, in response to individual or combined application of A. attenuatus and matrine at the end of the experimental period, were significantly lower than controls. The findings confirm the synergistic action of A. attenuatus and matrine against M. usitatus along with the biochemical phenomenon possibly regulating the synergistic effect.

A Review on Recent Advances in Aloperine Research: Pharmacological Activities and Underlying Biological Mechanisms

Aloperine, a quinolizidine-type alkaloid, was first isolated from the seeds and leaves of herbal plant, Sophora alopecuroides L. Empirically, Sophora alopecuroides L. is appreciated for its anti-dysentry effect, a property that is commonly observed in other Sophora Genus phytomedicines. Following the rationale of reductionism, subsequent biochemical analyses attribute such anti-dysentry effect to the bactericidal activity of aloperine. From then on, the multiple roles of aloperine are gradually revealed. Accumulating evidence suggests that aloperine possesses multiple pharmacological activities and holds a promising potential in clinical conditions including skin hyper-sensitivity, tumor and inflammatory disorders etc.; however, the current knowledge on aloperine is interspersed and needs to be summarized. To facilitate further investigation, herein, we conclude the key pharmacological functions of aloperine, and most importantly, the underlying cellular and molecular mechanisms are clarified in detail to explain the functional mode of aloperine.

Biological Impact and Enzyme Activities of Spodoptera litura (Lepidoptera: Noctuidae) in Response to Synergistic Action of Matrine and Beauveria brongniartii

Matrine, a naturally occurring heterocyclic compound, has been shown to enhance the pathogenicity of the entomopathogenic fungus Beauveria brongniartii against Spodoptera litura. In the current study, the biological impacts and synergism activities of these two agents on nutritional efficiency and antioxidant enzymes in S. litura were explored. Our results showed a high antifeedant activity of B. brongniartii and matrine on S. litura. The S. litura larvae were unable to pupate and emerge when treated with combinations of matrine and B. brongniartii. Following on, we measured the activities of five important antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acetylcholinesterase (AChE), and glutathione-S-transferase (GST)] when treated with B. brongniartii SB010 (1 × 109 spores/ml), matrine (0.5 mg/ml), and B. brongniartii SB010 (1 × 109 spores/ml) + matrine (0.5 mg/ml). The results indicated the detoxification activity of the five enzymes in the fat body and hemolymph of S. litura when facing a combined B. brongniartii and matrine challenge. The activities of the enzymes were significantly lower than that of the control group 7 days post-treatment, indicating the inhibitory effect of the two xenobiotics. Matrine had better inhibition effects than B. brongniartii in a majority of the trials. The improved detoxification activity of the five enzymes may be the internal mechanism of synergism of matrine on B. brongniartii.

Evaluation of Botanicals for Management of Piercing-Sucking Pests and the Effect on Beneficial Arthropod Populations in Tea Trees Camellia sinensis (L.) O. Kuntze (Theaceae)

The tea green leafhopper Empoasca onukii Matsuda (Hemiptera: Cicadellidae), the orange spiny whitefly, Aleurocanthus spiniferus (Quaintanca) (Hemiptera: Aleyrodidae), and the green plant bugs Apolygus lucorum Meyer-Dür (Hemiptera: Miridae) are the important piercing-sucking herbivores in tea trees Camellia sinensis (L.) O. Kuntze (Theaceae). The goal of this study was to evaluate the laboratory toxicities and field control efficacies of botanical insecticides including matrine, azadirachtin, veratrine, and pyrethrin to three tea pests. Via leaf-dip bioassay, toxicity tests with botanical insecticides indicated that there were significant differences between the LC50 values for botanical insecticides within the same insect species. Matrine had the highest toxicity to E. onukii, A. spiniferus, and A. lucorum with the LC50 values of 2.35, 13.10, and 44.88 mg/liter, respectively. Field tests showed that, among four botanical insecticides, matrine at dose of 9 g a.i. ha-1 can significantly reduce the numbers of E. onukii and A. spiniferus and the infestation of A. lucorum on the tea plants. Furthermore, botanical insecticides matrine and azadirachtin had no obvious influence on the coccinellids, spiders, and parasitoids densities in tea plantations. The results of this study indicated that use of botanical insecticides, such as matrine, has the potential to manipulate the population of E. onukii, A. spiniferus, and A. lucorum and will be an effective and environmentally compatible strategy for the control of tea pests.

Preparation of Matrinic/Oxymatrinic Amide Derivatives as Insecticidal/Acaricidal Agents and Study on the Mechanisms of Action against Tetranychus cinnabarinus

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and β3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.

Bioactivity of an oxymatrine-based commercial formulation against Brevipalpus yothersi Baker and its effects on predatory mites in citrus groves

The acaricidal bioactivity of an oxymatrine-based commercial formulation against Brevipalpus yothersi Baker (Acari: Tenuipalpidae), a vector mite of the Citrus leprosis virus (CiLV), and its impact on predatory mites were assessed. For this purpose, laboratory and field assays using bioacaricide concentrations ranging from 0.5 to 2.0 mg L^-1 of oxymatrine were performed during the years from 2015 to 2016. Laboratory results showed that the oxymatrine-based commercial formulation does not cause deleterious effects on B. yothersi eggs; however, it causes high larval mortality. For adult females, the bioacaricide caused high acute toxicity and residual effect for at least 5 days after application. In the field, the bioacaricide exhibited high acaricidal activity against B. yothersi, with efficacy levels similar to that of synthetic acaricide spirodiclofen (48 mg L^-1) until 49 days after the application. The application of the bioacaricide did not negatively affect the population levels of phytoseiid predatory mites. Therefore, our results suggest that the oxymatrine-based commercial formulation is an important tool for management of the citrus leprosis mite in citrus groves.

Interference mechanism of Sophora alopecuroides L. alkaloids extract on host finding and selection of the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

Manipulating insect behavior through the deployment of semiochemicals offers a promising opportunity for protecting crops in a sustainable manner. Therefore, there is still a significant opportunity for the development of natural crop protectants as eco-friendly tools in pest management. In this context, the aim of the current investigation is to find a novel prophylactic against the Asian citrus psyllid (ACP) and to gain a better understanding of the host-finding and selection ability of the ACP towards Murraya paniculata seedlings treated with Sophora alopecuroides alkaloids extract (SAAE). Our results indicate that foliar application of SAAE influences the psyllid host-finding and selection process. The behavioral assay with M. paniculata seedlings treated with 15 and 30 mg/mL of SAAE, with masked visual cues, revealed that only 6.6 and 10.4% psyllids were able to locate the host in the vials. The results also indicate that citrus psyllids mainly rely on both visual and olfaction in host-finding and selection. In choice settling experiments, psyllids settled almost completely on control seedlings rather than on seedlings treated with SAAE at a concentration of 30 mg/mL. Chemical analyses of the alkaloids extract revealed the presence of sophocarpine (33.90%), sophoridine (6.23%), anagyrine (2.77%), matrine (2.38%), lupanine (1.68%) aphylline (0.89%), and sophoramine (0.75%). In further behavioral bioassays with the dominant alkaloids sophocarpine and sophoridine, the alkaloids repelled ACP at higher concentrations of 50 and 70 mg/mL as compared to SAAE. Furthermore, the 50 mg/mL (1:1, v/v) combination of sophocarpine and sophoridine displayed a synergistic effect and showed the maximum behavioral effect as compared to the individual alkaloid. Based on our results, SAAE makes M. paniculata seedlings unattractive to the psyllids, and therefore, alkaloids could be used in reducing the colonization of citrus plants, subsequently curtailing HLB infection.

Semisynthesis of Matrinic Acid/Alcohol/Ester Derivatives, Their Pesticidal Activities, and Investigation of Mechanisms of Action against Tetranychus cinnabarinus

To discover new natural-product-based potential pesticides, 85 matrinic acid/alcohol/ester derivatives were synthesized by structural modifications of a quinolizidine alkaloid matrine. N-(4-Methyl)benzylmatrinyl n-decylate (76) and N-(2-chloro)benzylmatrinyl n-undecylate (86) exhibited greater than seven-fold more pronounced acaricidal activity than matrine against Tetranychus cinnabarinus; N-(2-chloro)benzylmatrinyl benzoate (80) showed the most promising insecticidal activity against Mythimna separata. The carboxyl group of matrinic acids and introduction of n-decyl/ n-undecylcarbonyl into matrinic alcohols were important for the acaricidal activity; introduction of alkyloxy into the carboxyl of matrinic acids and introduction of the electron-withdrawing groups on the N-benzyl of matrinic esters were necessary for the insecticidal activity. Through RT-PCR and qRT-PCR analysis, it was shown that the lactam ring of matrine was vital for action on VGSC; opening the lactam ring of matrine and the alkylcarbonyl of side-chain were two important factors for acting with α1, α2, and α4 nAChR subunits; α1, α2, α4, and β3 subunits may be the target of action of compound 86 against T. cinnabarinus.

Toxicological and biochemical basis of synergism between the entomopathogenic fungus Lecanicillium muscarium and the insecticide matrine against Bemisia tabaci (Gennadius)

The sweetpotato whitefly Bemisia tabaci (Gennadius) was challenged with different combinations of matrine (insecticide) and Lecanicillium muscarium (entomopathogenic fungus). Our results revealed a synergistic relationship between matrine and L. muscarium on mortality and enzyme activities of B. tabaci. To illustrate the biochemical mechanisms involved in detoxification and immune responses of B. tabaci against both control agents, activities of different detoxifying and antioxidant enzymes were quantified. After combined application of matrine and L. muscarium, activities of carboxylestrease (CarE), glutathione-s-transferase (GSTs) and chitinase (CHI) decreased during the initial infection period. Acetylcholinestrase (AChE) activities increased during the entire experimental period, whereas those of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) decreased during the later infection period. The increased mortality and suppression of enzymatic response of B. tabaci following matrine and L. muscarium application suggests a strong synergistic effect between both agents. The strong synergistic effect is possibly related to the disturbance of acetylcholine balance and changes in AchE activities of the whitefly as both matrine and L. muscarium target insect acetylcholine (Ach) receptors which in turn effects AchE production. Therefore, our results have revealed the complex biochemical processes involved in the synergistic action of matrine and L. muscarium against B. tabaci.

Acaricidal activity and sublethal effects of an oxymatrine-based biopesticide on two-spotted spider mite (Acari: Tetranychidae)

Lethal and sublethal effects of the biopesticide Kingbo (oxymatrine 0.2 % + psoralen 0.4 %) on the two-spotted spider mite (Tetranychus urticae Koch) were investigated in laboratory bioassays. The biopesticide was applied to bean leaf discs or primary leaves by using a Potter spray tower. Acute toxicity tests showed no significant ovicidal action: toxic effect (LC50 = 55.49 μl/l) was the result of a residual activity against larvae that hatched from the treated eggs. Preovipositional females and female teleiochrysales showed similar susceptibility (LC50 = 52.68 and 59.03 μl/l, respectively), whereas larvae, protonymphs and female deutonymphs were the most susceptible stages (LC50 = 6.88, 13.03, and 8.80 μl/l, respectively). In a choice test, females preferred the untreated halves of leaves over the halves treated with 2,000, 1,000, and 500 μl/l in the first 24 h, and their oviposition in those treatments was significantly greater on the untreated halves after 24 and 48 h, as well as the summed oviposition over 72 h. Viability and reproduction of survivors, as well as population growth, were strongly affected after the treatments of preovipositional females and female teleiochrysales with 100, 50 and 25 μl/l. On the other hand, sublethal effects on the females that survived treatment at the egg stage or reached adulthood from the eggs laid on the treated surface (treatments with 50 and 25 μl/l) were significantly weaker. Acaricidal and sublethal effects of the biopesticide Kingbo were discussed as a starting point for further research aimed to improve management of T. urticae populations. Regulatory issues and safety concerns regarding further commercialization of this biopesticide are addressed as well.

Developmental toxicity and neurotoxicity of two matrine-type alkaloids, matrine and sophocarpine, in zebrafish (Danio rerio) embryos/larvae

Matrine and sophocarpine are two major matrine-type alkaloids included in the traditional Chinese medicine (TCM) Kushen (the root of Sophora flavescens Ait.). They have been widely used clinically in China, however with few reports concerning their potential toxicities. This study investigated the developmental toxicity and neurotoxicity of matrine and sophocarpine on zebrafish embryos/larvae from 0 to 96/120h post fertilization (hpf). Both drugs displayed teratogenic and lethal effects with the EC50 and LC50 values at 145 and 240mg/L for matrine and 87.1 and 166mg/L for sophocarpine, respectively. Exposure of matrine and sophocarpine significantly altered spontaneous movement and inhibited swimming performance at concentrations below those causing lethality and malformations, indicating a neurotoxic potential of both drugs. The results are in agreement with most mammalian studies and clinical observations.

Podophyllotoxin Derivatives Show Activity against Brontispa Longissima Larvae

In an attempt to find biorational insecticides, eleven podophyllotoxin analogues were tested for their insecticidal activity against the fifth-instar larvae of Brontispa longissima in vivo for the first time. Among all of the tested compounds, deoxypodophyllotoxin (3) and β-apopicropodophyllin (4) showed more promising and pronounced insecticidal activity than toosendanin, a commercial insecticide derived from Melia toosendan, and important SAR information has been revealed. Together, these preliminary results may be useful in guiding further modification of podophyllotoxins in the development of potential new insecticides.