Bioassay-guided isolation of potent aphicidal Erythrina alkaloids against Aphis gossypii from the seed of Erythrina crista-galli L

Flupyradifurone negatively affects survival, physical condition and mobility in the two-spotted lady beetle (Adalia bipunctata)

Lady beetles play a crucial role in natural ecosystems and agricultural settings. Unfortunately, these insects and more specifically the two-spotted lady beetle (Adalia bipunctata) are currently facing a severe decline in populations due to various stressors, with pesticide exposure being a significant threat. Flupyradifurone is a relatively newly introduced insecticide and as existing research is mainly elucidating its effects on bees there remains a limited understanding of its effects on non-hymenopteran insects, including lady beetles. In this study we investigated the impact of acute orally applied flupyradifurone doses on survival and sublethal parameters such as physical condition and mobility on A. bipunctata. Our findings revealed a significant increase in mortality among individuals subjected to flupyradifurone doses of 19 ng/individual (corresponding to >1.5-2.0 ng active substance (a.s.)/mg body weight (bw). The calculated LD50 of flupyradifurone at 48 h was 2.11 ng a.s./mg bw corresponding to an amount of 26.38 ng/individual. Sublethal consequences were observable immediately after pesticide application. Even at doses as low as 2 ng/individual (corresponding to >0.0-0.5 ng a.s./mg bw), flupyradifurone induced trembling and temporary immobility in treated animals. Furthermore, pesticide intoxication led to hypoactivity, with less distance covered and a decline in straightness of locomotion. In conclusion, our study underscores the harmful effects of flupyradifurone on the two-spotted lady beetle at doses notably lower than those affecting bees. These findings stress the importance of additional research to attain a more holistic understanding of pesticide impacts not only on a broader range of non-target arthropods species, but also on various exposure routes as well as lethal and sublethal effects.

Metabolomic study of the estrogenic and anti-osteoporotic potential of Erythrina bidwillii leaf

Erythrina bidwillii Lindl., Leguminosae, constitutes a valuable crop for horticulture and medicine; however, it is rarely investigated. Menopause is a crucial transitional period in women's health. Women worldwide consider the use of phytoestrogens as a safe hormone replacement therapy to alleviate detrimental menopausal symptoms. Thus, the discovery of novel phytoestrogens is highly demanded. The present study aimed to investigate, for the first time, the metabolomic profile and the estrogenic potential of E. bidwillii Lindl. leaf. Ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry and gas chromatography-mass spectrometry metabolite profiling revealed the prevalence of alkaloids, flavonoids, isoflavonoids and fatty acids. Additionally, five erythrinan alkaloids, cristanine A (1), 8-oxoerythraline (2), (+)-erythrinine (3), (+)-erythraline (4) and 8-oxoerythrinine (5), along with the isoflavonoid genistin (6), were isolated. Erythrina bidwillii leaf extract exhibited significant in vivo estrogenic, anti-osteoporotic, anti-hyperlipidemic, hepatoprotective, and nephroprotective activities, utilizing ovariectomized rat model. Moreover, ethyl acetate and hexane fractions possessed significant in vitro estrogeic potential on MCF-7 cell lines. An in silico study of the isolated metabolites revealed that (+)-erythrinine (3) and 8-oxoerythrinine (5) exhibited the highest affinity for ERα and ERβ, respectively, modeling them as potential estrogenic lead metabolites. Therefore, E. bidwillii leaf could be employed as promising hormone replacement therapy for postmenopausal women after thorough clinical trials.

RNA interference of NADPH-cytochrome P450 reductase increases the susceptibility of Aphis gossypii Glover to sulfoxaflor

NADPH-cytochrome P450 reductase (CPR) is essential for the detoxification of endogenous and exogenous substances mediated by cytochrome P450. While several insect CPRs have been found to be associated with insecticide resistance, the CPR of Aphis gossypii has not been characterized, and its functional role in insecticide resistance remains undefined. In this study, we cloned and characterized the full-length sequence of A. gossypii CPR (AgCPR). The deduced amino acid sequence of AgCPR contains all conserved domains of CPR, which shows high similarity to other insect CPRs and was clustered into a same branch of aphids according to phylogenetic analysis. The transcript of AgCPR was present in all developmental stages, with the highest expression in the adult stage. Furthermore, the expression of AgCPR could be induced by sulfoxaflor, a commonly used insecticide, in a time- and dose-dependent manner. Further silencing of AgCPR by feeding dsRNA significantly increased the susceptibility of A. gossypii to this insecticide. These findings suggest that AgCPR may play a significant role in the susceptibility of A. gossypii to sulfoxaflor and in the development of P450-mediated resistance to sulfoxaflor.

Influence of the pesticide flupyradifurone on mobility and physical condition of larval green lacewings

Global pesticide use in agriculture is one reason for the rapid insect decline in recent years. The relatively new pesticide flupyradifurone is neurotoxic to pest insects but considered harmless to bees according to previous risk assessments. With this study, we aim to investigate lethal and sublethal effects of flupyradifurone on larvae of the beneficial arthropod Chrysoperla carnea. We treated the animals orally with field-realistic concentrations of flupyradifurone and examined lethality as well as effects on condition, mobility and locomotion. For the lethal dose 50, we determined a value of > 120-200 ng/mg (corresponding to a mean amount of 219 ng/larva) after 168 h. Abnormal behaviors such as trembling and comatose larvae were observed even at the lowest concentration applied (> 0-20 ng/mg, 59 ng/larva). Mobility analysis showed impaired activity patterns, resulting in acute hypoactivity at all pesticide concentrations and time-delayed hyperactivity in larvae treated with > 40-60 ng/mg (100 ng/larva) and > 80-100 ng/mg (120 ng/larva), respectively. Even locomotion as a fundamental behavioral task was negatively influenced throughout larval development. In conclusion, our results demonstrate that flupyradifurone impacts life and survival of lacewing larvae and may pose-despite its status as bee-friendly-a major threat to insect fauna and environment.

Characterization, expression, and functional analysis of TRPV genes in cotton aphid, Aphis gossypii Glover

Transient receptor potential vanilloid (TRPV) channels have been found to be the molecular target of afidopyropen, a novel insecticide that is highly effective in controlling Aphis gossypii Glover in the field. However, the TRPV genes of A. gossypii has not yet been characterized. In this study, two TRPV genes of A. gossypii (AgNan and AgIav) were cloned and their expression levels were determined by quantitative real-time PCR (RT-qPCR). The deduced amino acids of AgNan and AgIav contain all conserved domains of TRPV and share very high amino acid identity with other insect TRPVs. AgNan and AgIav expressed in all developmental stages and their expression can be induced by afidopyropen in a dose- and time-dependent manner. Moreover, we found that silencing of AgNan and AgIav by RNA interference resulted in a significant mortality increase of adult A. gossypii compared to the control, which was even higher than 93 % at five days after feeding with dsAgIav, suggesting that knockdown of AgNan and AgIav have great effects on the survival of A. gossypii. The results of this study would be helpful for determining the reasonable use of afidopyropen in the integrated pest management programs of A. gossypii and provide useful information for further functional study of TRPVs in insects.

Potent insecticidal activity of Eleocharis dulcis (Burm. f.) Trin peel extract and its main components against aphids

BACKGROUND

Aphids are significant pests of cash crops and food farm crops. Botanical insecticides are safe for aphid control, especially for organic farming. In this study, Eleocharis dulcis (Burm. f.) Trin. peel extract (EDPE), a new botanical insecticide, was investigated for its active compositions against several agricultural aphids.

RESULTS

The results showed that the EDPE had high insecticidal activity against Sitobion avenae Fabricius, Aphis gossypii Glover, Megoura crassicauda Mordvilko, and Acyrthosiphon pisum Harris, with half-lethal concentration (LC₅₀ ) values of 95.92, 81.04, 140.31, and 255.73 mg/L after 48 h of treatment. In the pot culture assay, the aphicidal effects of 25% EDPE soluble liquid (SL) at a concentration of 0.016% were 68.98 ± 5.61%, 79.33 ± 8.27%, and 88.82 ± 3.91% after the first, third, and seventh days of treatment, respectively. Nine compounds were identified by bioactivity-directed fractionation: 4',5'-dimethoxy-6,6-dimethylpyranoisoflavone (1), 3-methoxy-4-hydroxylonchocarpin (2), 4-hydroxylonchocarpin (3), 4-methoxylonchocarpin (4), barbigerone (5), lonchocarpusone (6), 6a,12a-dehydrodeguelin (7), 13-homo-13-oxa-6a, 12a-dehydrodeguelin (8) and deguelin (9). Among them, 4-hydroxylonchocarpin (3) showed the highest aphidicidal activity against M. crassicauda, S. avenae, and A. pisum, with LC₅₀ values of 97.24, 140.63, and 112.31 mg/L, respectively.

CONCLUSION

These data contribute to a better understanding of the aphicidal activity of EDPE and its main component, 4-hydroxylonchocarpin. This will help to develop new botanical insecticides to contro aphids. © 2022 Society of Chemical Industry.

Natural products-based: Synthesis and antifungal activity evaluation of novel L-pyroglutamic acid analogues

Botanical pesticides are one of the sources of third-generation pesticides, which have received much attention at home and abroad in recent years due to their degradable and pollution-free advantages in nature. This article explored a concise approach toward synthesizing a series of novel L-pyroglutamic acid analogues from L-hydroxyproline. Furthermore, bioassay studies of these sulfonyl ester derivatives against Pyricularia oryzae, Fusarium graminearum, Alternaria brassicae, Valsa mali, and Alternaria alternariae showed moderate antifungal activity. For instance, C08a and C08l provide potential lead agents for controlling Fusarium graminearum because of their inhibitory activity.

Systematic Review of Potential Anticancerous Activities of Erythrina senegalensis DC (Fabaceae)

The objective of this study was to carry out a systematic review of the substances isolated from the African medicinal plant Erythrina senegalensis, focusing on compounds harboring activities against cancer models detailed in depth herein at both in vitro and in vivo preclinical levels. The review was conducted through Pubmed and Google Scholar. Nineteen out of the forty-two secondary metabolites isolated to date from E. senegalensis displayed interesting in vitro and/or in vivo antitumor activities. They belonged to alkaloid (Erysodine), triterpenes (Erythrodiol, maniladiol, oleanolic acid), prenylated isoflavonoids (senegalensin, erysenegalensein E, erysenegalensein M, alpinumisoflavone, derrone, warangalone), flavonoids (erythrisenegalone, senegalensein, lupinifolin, carpachromene) and pterocarpans (erybraedine A, erybraedine C, phaseollin). Among the isoflavonoids called "erysenegalensein", only erysenealenseins E and M have been tested for their anticancerous properties and turned out to be cytotoxic. Although the stem bark is the most frequently used part of the plant, all pterocarpans were isolated from roots and all alkaloids from seeds. The mechanisms of action of its metabolites include apoptosis, pyroptosis, autophagy and mitophagy via the modulation of cytoplasmic proteins, miRNA and enzymes involved in critical pathways deregulated in cancer. Alpinumisoflavone and oleanolic acid were studied in a broad spectrum of cancer models both in vitro and in preclinical models in vivo with promising results. Other metabolites, including carpachromen, phaseollin, erybraedin A, erysenegalensein M and maniladiol need to be further investigated, as they display potent in vitro effects.

Combining Multi-Dimensional Convolutional Neural Network (CNN) With Visualization Method for Detection of Aphis gossypii Glover Infection in Cotton Leaves Using Hyperspectral Imaging

Cotton is a significant economic crop. It is vulnerable to aphids (Aphis gossypii Glovers) during the growth period. Rapid and early detection has become an important means to deal with aphids in cotton. In this study, the visible/near-infrared (Vis/NIR) hyperspectral imaging system (376-1044 nm) and machine learning methods were used to identify aphid infection in cotton leaves. Both tall and short cotton plants (Lumianyan 24) were inoculated with aphids, and the corresponding plants without aphids were used as control. The hyperspectral images (HSIs) were acquired five times at an interval of 5 days. The healthy and infected leaves were used to establish the datasets, with each leaf as a sample. The spectra and RGB images of each cotton leaf were extracted from the hyperspectral images for one-dimensional (1D) and two-dimensional (2D) analysis. The hyperspectral images of each leaf were used for three-dimensional (3D) analysis. Convolutional Neural Networks (CNNs) were used for identification and compared with conventional machine learning methods. For the extracted spectra, 1D CNN had a fine classification performance, and the classification accuracy could reach 98%. For RGB images, 2D CNN had a better classification performance. For HSIs, 3D CNN performed moderately and performed better than 2D CNN. On the whole, CNN performed relatively better than conventional machine learning methods. In the process of 1D, 2D, and 3D CNN visualization, the important wavelength ranges were analyzed in 1D and 3D CNN visualization, and the importance of wavelength ranges and spatial regions were analyzed in 2D and 3D CNN visualization. The overall results in this study illustrated the feasibility of using hyperspectral imaging combined with multi-dimensional CNN to detect aphid infection in cotton leaves, providing a new alternative for pest infection detection in plants.

Biologically active indolizidine alkaloids

Indolizidine alkaloids are chemical constituents isolated from various marine and terrestrial plants and animals, including but not limited to trees, fungi, ants, and frogs, with a myriad of important biological activities. In this review, we discuss the biological activity and pharmacological effects of indolizidine alkaloids and offer new avenues toward the discovery of new and better drugs based on these naturally occurring compounds.

Berberine induces resistance against tobacco mosaic virus in tobacco

BACKGROUND

Plant systemic resistance induced by botanical compounds is a promising alternative method of disease management. The natural product berberine, usually used as an antimicrobial in medicine, has been proven to have antifungal activity in agriculture. To investigate the induced resistance imparted by berberine, the effect of berberine against tobacco mosaic virus (TMV) and the mechanism governing this effect were determined.

RESULT

Berberine exhibited considerable in vivo anti-TMV activity of up to 68.3% but had no in vitro direct effect on TMV. Moreover, berberine could induce immune responses against TMV in tobacco, including the hypersensitive reaction (HR), accumulation of H2 O2 , increases in defense enzymes and overexpression of pathogenesis-related (PR) proteins. In addition, upregulation of salicylic acid (SA) biosynthesis genes PAL, CM1, ICS, PBS3 and the enzyme benzoic acid 2-hydroxylase (BA2H) confirmed that SA was involved in the defensive signals. Berberine can induce crop resistance against TMV, Phytophthora nicotianae, Botrytis cinerea and Blumeria graminis in the greenhouse.

CONCLUSION

This paper highlights the use of berberine in manipulating tobacco to generate defense responses against TMV, which can be attributed to SA-mediated induced resistance. The paper provides a theoretical basis for the application of berberine as a resistance activator and for further research on induced resistance by botanical natural product. © 2019 Society of Chemical Industry.

Toxicity and sublethal effects of two plant allelochemicals on the demographical traits of cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae)

Plant allelochemicals are a group of secondary metabolites produced by plants to defend against herbivore. The mortality of two plant allelochemicals (tannic acid and gossypol) on the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), were investigated using feeding assays and the sublethal effects were evaluated using the age-stage, two-sex life table approach. Tannic acid and gossypol have deleterious effects on A. gossypii, and as the concentrations increased, the mortality of cotton aphid increased. The life history traits of A. gossypii including the developmental duration of each nymph stage, the longevity, oviposition days, total preadult survival rate and adult pre-oviposition period were not significantly affected by sublethal concentration of tannic acid (20 mg/L) and gossypol (50 mg/L), while the population parameters (r, λ and R₀) were significantly affected by these two plant allelochemicals. Furthermore, tannic acid can increase the pre-adult duration time and TPOP but reduce the fecundity of A. gossypii significantly compared to the control and gossypol treatment groups. These results are helpful for comprehensively understanding the effects of plant allelochemicals on A. gossypii.

Alkaloids of genus Erythrina: An updated review

Genus Erythrina (Fabaceae) comprises several species, which are widely distributed in tropical and subtropical regions of the world. The plants of this genus exhibited significant role in traditional medicine targeting different diseases. Alkaloids and flavonoids were reported as the chief bioactive constituents of this genus with a wide range of biological activities. About 143 alkaloids were isolated from Erythrina sp. Anticonvulsant, anxiolytic, curare-like activity, insecticidal and cytotoxic activities were reported for Erythrina sp. alkaloids. The present work is an overview of the isolated alkaloids from Erythrina sp. with their reported biological activities.[Figure: see text]Abbreviations: CHCl3: Chloroform; CNS: Central nervous system; DCM: Methylene chloride; DPPH: 2,2-Diphenyl-1-picrylhydrazyl; E.: Erythrina; ERα/β: Estrogen receptors α/β; EtOAc: Ethyl acetate; EtOH: Ethanol; Hep-G2: Human liver carcinoma cell lines; HIV: Human immunodeficiency virus; HL-60: Human promyelocytic leukemia cells; K-562: Human immortalized myelogenous leukemia cell line; LPS: Lipopolysaccharide; MeOH: Methanol; MOLT-4: Acute lymphoblastic leukemia cell line; nAChRs: nicotinic acetylcholine receptors; NO: Nitric oxide; NREM: non-rapid eye movement; Pet. ether: Petroleum ether; RBA: Receptor binder affinity; TRAIL: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand.

Thrips Resistance Screening Is Coming of Age: Leaf Position and Ontogeny Are Important Determinants of Leaf-Based Resistance in Pepper

Capsicum is a genus containing important crop species, many of which severely suffer from thrips infestation. Thrips feeding damages leaves and fruits, and often results in virus infections. Only a few insecticides are still effective against thrips, underlining the importance of finding natural resistance in crops. Capsicum is a perennial plant which is usually cultivated for several months, during which time the fruits are harvested. From the young vegetative stage to the mature fruit bearing stage, the plants are at risk to thrips infestation. Constitutive resistance to thrips over the entire ontogenetic development is therefore a key trait for a more sustainable and successful cultivation of the hot and sweet pepper. In addition to ontogeny, leaf position can affect the level of thrips resistance. Pest resistance levels are known to differ between young and old leaves. To our knowledge, no studies have explicitly considered ontogeny and leaf position when screening for constitutive resistance to thrips in Capsicum. In this study we analyze whether ontogeny and leaf position affect leaf-based resistance to Frankliniella occidentalis and Thrips tabaci, in 40 Capsicum accessions, comprising five different species. Our results show that resistance to both thrips species in Capsicum varies with ontogenetic stage. This variation in resistance among ontogenetic stages was not consistent among the accessions. However, accessions with constitutive resistance in both the flowering and fruit ripening stage could be identified. In addition, we found that thrips resistance is overall similar at different leaf positions within the ontogenetic stage. This implies that resistance mechanisms, such as defense compounds, are constitutively present at sufficient levels on all leaf positions. Finally, we found that resistance to F. occidentalis and resistance to T. tabaci were not correlated. This indicates that leaf-based resistance in Capsicum is thrips species-specific. Because of the variation in resistance over ontogeny, identifying Capsicum accessions with resistance over their entire lifespan is challenging. For resistance screening, accounting for leaf position may be less of a concern. To identify the defense mechanisms responsible for thrips resistance, it is important to further analyze and compare resistant and susceptible accessions.

The genus Erythrina L.: A review on its alkaloids, preclinical, and clinical studies

Erythrina L. genus (Fabaceae) comprises about 115 species, and it has been extensively studied, mainly because of its alkaloids, which have pharmacological properties. References demonstrated that Erythrina spp. have a potential to act in the central nervous system, presenting anxiolytic and anticonvulsant properties already established. Phytochemical investigations confirmed the presence of tetracyclic alkaloids as the major compounds. However, other alkaloid classes have also been reported, including dimeric and trimeric substances, coupled through direct polymerization or two erythrinine units via an acetyl glucose. The present review covers the relevant literature from 1990 until 2017 and outlines the current data on chemical composition and preclinical and clinical studies on Erythrina species. Additionally, the quite striking analogy in the biosynthetic route of erythrin, morphinans, and Amaryllidaceae family alkaloids was also discussed.

An Update of Erythrinan Alkaloids and Their Pharmacological Activities

The period of the past 5 years has witnessed a remarkable increase in all of the number, structural variety, and complexity of erythrinan alkaloids reported. This structural diversity seems to be most pronounced in the alkaloids reported from the two species Erythrina arborescens and Erythrina variegata. Between them, work-up of these taxa yielded new polymeric (dimeric and trimeric) erythrinan alkaloids, a first example in one case where a normal 6,5,6,6-membered indoloisoquinoline spirocylic core has rearranged to a spiro-fused 6,5,7,6-skeleton. Furthermore, erythrinan alkaloids with a fifth ring containing a 2H-imidazole functionality were also reported for the first time, together with some new structures having an unusual substitution and with functionalities at positions C-3 and C-7 of the erythrinan core. This contribution has included 40 more erythrinan alkaloids that are either new or were omitted in the most recent major reviews on the same topic, leading to a total of 154 known erythrinan alkaloids to date. There are a few cases where the structures of the new alkaloids are contestable due to insufficient data having been obtained on isolation. To facilitate easier reference and identification, all structures having a common core have been placed in the same table or figure in this chapter.The reported pharmacological activities of the new and known erythrinan alkaloids documented have shown a considerable bias towards central nervous system and related activities. Other prominent activities that have been reported are antifeedant, insecticidal, cytotoxic, antiprotozoal, anti-inflammatory, antioxidant, antifungal, and antiviral effects. Erythrinan alkaloids generally seem to lack antibacterial activity. Several new polymeric alkaloids were found to lack cytotoxicity against a number of human cancer cell lines, although two of them showed moderate aphicidal activity and one exhibited weak to moderate acetylcholinesterase inhibition. The biological activity of erythrinan alkaloids seems to be influenced by basic substructural requirements, such as a conjugated diene (Δ^1,2, Δ^6,7) system and is modulated by the presence (or absence) of other groups in rings A, B, C, and D of the erythrinan core. The erythrinan core may provide potential leads to structures that eventually may be useful therapeutically.In recent years, a number of stereoselective chemical synthesis methods have been applied towards the erythinan alkaloids, and these are described in this contribution.