Plant toxins that affect nicotinic acetylcholine receptors: a review

Acute death as a result of poisoning tropical (Bos taurus indicus) but not temperate (Bos taurus taurus) cattle after oral dosing with Lupinus leucophyllus (velvet lupine)

Due to climate change and increasing summer temperatures, tropical cattle may graze where temperate cattle have grazed, exposing tropical cattle to toxic plants they may be unfamiliar with. This work compared the toxicity of Lupinus leucophyllus (velvet lupine) in temperate and tropical cattle. Orally dosed velvet lupine in tropical cattle caused death. If producers opt to graze tropical cattle, additional care must be taken on rangelands where toxic lupines like velvet lupine grow.

MultiToxPred 1.0: a novel comprehensive tool for predicting 27 classes of protein toxins using an ensemble machine learning approach

Protein toxins are defense mechanisms and adaptations found in various organisms and microorganisms, and their use in scientific research as therapeutic candidates is gaining relevance due to their effectiveness and specificity against cellular targets. However, discovering these toxins is time-consuming and expensive. In silico tools, particularly those based on machine learning and deep learning, have emerged as valuable resources to address this challenge. Existing tools primarily focus on binary classification, determining whether a protein is a toxin or not, and occasionally identifying specific types of toxins. For the first time, we propose a novel approach capable of classifying protein toxins into 27 distinct categories based on their mode of action within cells. To accomplish this, we assessed multiple machine learning techniques and found that an ensemble model incorporating the Light Gradient Boosting Machine and Quadratic Discriminant Analysis algorithms exhibited the best performance. During the tenfold cross-validation on the training dataset, our model exhibited notable metrics: 0.840 accuracy, 0.827 F1 score, 0.836 precision, 0.840 sensitivity, and 0.989 AUC. In the testing stage, using an independent dataset, the model achieved 0.846 accuracy, 0.838 F1 score, 0.847 precision, 0.849 sensitivity, and 0.991 AUC. These results present a powerful next-generation tool called MultiToxPred 1.0, accessible through a web application. We believe that MultiToxPred 1.0 has the potential to become an indispensable resource for researchers, facilitating the efficient identification of protein toxins. By leveraging this tool, scientists can accelerate their search for these toxins and advance their understanding of their therapeutic potential.

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.

Biomarkers and their potential for detecting livestock plant poisonings in Western North America

The United States National Cancer Institute defines a biomarker as: "A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease." In Veterinary Medicine, biomarkers associated with plant poisonings of livestock have great utility. Since grazing livestock poisoned by toxic plants are often found dead, biomarkers of plant poisoning allow for a more rapid postmortem diagnosis and response to prevent further deaths. The presence and concentration of toxins in poisonous plants are biomarkers of risk for livestock poisoning that can be measured by the chemical analysis of plant material. More difficult is, the detection of plant toxins or biomarkers in biological samples from intoxicated or deceased animals. The purpose of this article is to review potential biomarkers of plant poisoning in grazing livestock in the Western North America including recently investigated non-invasive sampling techniques. Plants discussed include larkspur, lupine, water hemlock, swainsonine-containing plants, selenium-containing plants, and pyrrolizidine alkaloid containing plants. Other factors such as animal age and sex that affect plant biomarker concentrations in vivo are also discussed.

Poisonous Piperidine Plants and the Biodiversity of Norditerpenoid Alkaloids for Leads in Drug Discovery: Experimental Aspects

There are famous examples of simple (e.g., hemlock, Conium maculatum L.) and complex (e.g., opium poppy, Papaver somniferum L., Papaveraceae) piperidine-alkaloid-containing plants. Many of these are highly poisonous, whilst pepper is well-known gastronomically, and several substituted piperidine alkaloids are therapeutically beneficial as a function of dose and mode of action. This review covers the taxonomy of the genera Aconitum, Delphinium, and the controversial Consolida. As part of studying the biodiversity of norditerpenoid alkaloids (NDAS), the majority of which possess an N-ethyl group, we also quantified the fragment occurrence count in the SciFinder database for NDA skeletons. The wide range of NDA biodiversity is also captured in a review of over 100 recently reported isolated alkaloids. Ring A substitution at position 1 is important to determine the NDA skeleton conformation. In this overview of naturally occurring highly oxygenated NDAs from traditional Aconitum and Delphinium plants, consideration is given to functional effect and to real functional evidence. Their high potential biological activity makes them useful candidate molecules for further investigation as lead compounds in the development of selective drugs.

Comparative transcriptome analysis of Lupinus polyphyllus Lindl. provides a rich molecular resource for research on coloration mechanism

Lupinus polyphyllus is rich in color, making it a well-known horticultural ornamental plant. However, little is known about the genes related to anthocyanin and carotenoid biosynthesis in L. polyphyllus. In this study, transcriptome sequencing was performed on eight different colors of L. polyphyllus. A total of 1.13 billion clean reads were obtained and assembled into 89,124 unigenes, which were then aligned with six databases, resulting in the identification of 54,823 annotated unigenes. Among these unigenes, 76 and 101 were involved in the biosynthetic pathway of carotenoids and anthocyanins, respectively. In addition, 505 transcription factors were revealed, which belonged to the MYB, R2R3-MYB, NAC, bHLH, and WD40 families. A total of 6,700 differentially expressed genes (DEGs) were obtained by comparative transcriptome analysis. Among them, 17 candidate unigenes (four carotenoid genes, seven anthocyanin genes, and six TFs) were specifically up-regulated for one or more colors of L. polyphyllus. Eight representative candidate unigenes were analyzed by qRT-PCR. The findings enrich the transcriptome database of lupine, and provide a rich molecular resource for research on the coloration mechanism of L. polyphyllus.

Nanoemulsified Formulation of Cedrela odorata Essential Oil and Its Larvicidal Effect against Spodoptera frugiperda (J.E. Smith)

Cedrela odorata L. is a plant species from the Meliaceae family that is cultivated for timber production. Although the C. odorata essential oil (EO) contains mainly sesquiterpenes, its insecticidal potential is unknown. The lipophilic properties and high degradation capacity of EOs have limited their application for use in pest control. However, the currently available knowledge on the nanoemulsification of EOs, in addition to the possibility of improving their dispersion, would allow them to prolong their permanence in the field. The objective of the present work was to develop a nanoemulsion of the C. odorata EO and to evaluate its larvicidal activity against Spodoptera frugiperda. The EO was obtained by the hydrodistillation of C. odorata dehydrated leaves, and the nanoemulsion was prepared with non-ionic surfactants (Tween 80 and Span 80) using a combined method of agitation and dispersion with ultrasound. The stability of the nanoemulsion with a droplet diameter of <200 nm was verified in samples stored at 5 °C and 25 °C for 90 days. Both the C. odorata EO and its corresponding nanoemulsion presented lethal properties against S. frugiperda. The results obtained provide guidelines for the use of wood waste to produce sustainable and effective insecticides in the fight against S. frugiperda. In addition, considering that a phytochemical complex mixture allows the simultaneous activation of different action mechanisms, the development of resistance in insects is slower.

Mineral-salt supplementation to ameliorate larkspur poisoning in cattle

Larkspurs (Delphinium spp.) are native forbs that are poisonous to cattle and cost livestock producers millions of dollars in losses each year. Macro and micro minerals are required for normal functioning of essentially all metabolic processes in ruminants. The role that mineral status may play in larkspur poisoning in cattle is not clear. In this study, we seek to determine the effects a mineral-salt supplement, commonly used by cattle producers, to potentially reduce cattle losses to larkspur. The ability of mineral-salt supplementation to alter susceptibility to larkspur toxicosis was evaluated in a pen study. Animals supplemented with mineral-salt were found to be less susceptible to larkspur poisoning than the non-supplemented animals. A separate group of animals were then grazed on larkspur infested rangelands. One group was supplemented with a mineral-salt mix and the other group did not receive any mineral-salt. Supplementing cattle with the mineral-salt mix did not alter larkspur consumption (P > 0.05). However, overall larkspur consumption was low and averaged 3 ± 1.0% and 2 ± 1.1% for cattle supplemented with mineral and non-supplemented, respectively. Serum was collected from animals once a week during the grazing study. Average and maximum serum concentrations of toxic larkspur alkaloids were numerically higher in mineral-salt supplemented cattle compared with the non-supplemented animals. Results from the pen study suggest that a good mineral supplementation program will provide a protective effect for animals grazing in larkspur-infested ranges. The mineral-salt supplemented steers, in the grazing study, were not observed to consume less larkspur than the non-supplemented animals; however, the mineral-salt supplemented animals had higher concentrations of larkspur alkaloids in their serum indicating they may be able to tolerate higher larkspur consumption. The data also indicate that mineral-salt supplementation must be continuous throughout the time the animals are grazing these rangelands as the positive effects can be lost within 30 d post supplementation.

Biological Activity of Phytochemicals from Agricultural Wastes and Weeds on Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) is a polyphagous insect pest native to America. Due to its capacity for adaptation and migration, it is currently located in Africa, Asia, and Oceania, where it threatens agricultural crops. The ability of S. frugiperda to develop resistance to insecticides is one of the reasons for the continuous search for more effective, low-cost, and environmentally friendly control products. In the present work, the insecticidal activity of ethanolic and hexane extracts obtained from fresh and dehydrated leaves of Piper auritum Kunth (Piperales: Piperaceae), Piper umbellatum L. (Piperales: Piperaceae), and Cedrela odorata L. (Sapindales: Meliaceae) was studied against first instar larvae of S. frugiperda. The ethanolic extracts of the dehydrated leaves of C. odorata and P. auritum presented insecticidal activity as high (100% mortality at a concentration of 92 mg/cm2) as that obtained with the positive control, Melia azedarach L. (Sapindales: Meliaceae). The GC-MS analysis of the extracts revealed the presence of phytochemicals classified mainly into the groups of monoterpenes, sesquiterpenes, diterpenes, phenylpropanoids, alcohols, and fatty acids. P. auritum grows and propagates rapidly. In addition, due to its low toxicity in mammals and non-target insects, it is a plant with the potential to be used as a botanical insecticide. The exposure of S. frugiperda larvae to low concentrations of ethanolic extract of P. auritum allowed us to observe their biological activity in the development of this insect. The LC50 was 22.1 mg/cm2. At sublethal concentrations (LC21 and LC35) the low fertility of the emerging adults was noticeable.

Plant-Derived Pesticides as an Alternative to Pest Management and Sustainable Agricultural Production: Prospects, Applications and Challenges

Pests and diseases are responsible for most of the losses related to agricultural crops, either in the field or in storage. Moreover, due to indiscriminate use of synthetic pesticides over the years, several issues have come along, such as pest resistance and contamination of important planet sources, such as water, air and soil. Therefore, in order to improve efficiency of crop production and reduce food crisis in a sustainable manner, while preserving consumer's health, plant-derived pesticides may be a green alternative to synthetic ones. They are cheap, biodegradable, ecofriendly and act by several mechanisms of action in a more specific way, suggesting that they are less of a hazard to humans and the environment. Natural plant products with bioactivity toward insects include several classes of molecules, for example: terpenes, flavonoids, alkaloids, polyphenols, cyanogenic glucosides, quinones, amides, aldehydes, thiophenes, amino acids, saccharides and polyketides (which is not an exhaustive list of insecticidal substances). In general, those compounds have important ecological activities in nature, such as: antifeedant, attractant, nematicide, fungicide, repellent, insecticide, insect growth regulator and allelopathic agents, acting as a promising source for novel pest control agents or biopesticides. However, several factors appear to limit their commercialization. In this critical review, a compilation of plant-derived metabolites, along with their corresponding toxicology and mechanisms of action, will be approached, as well as the different strategies developed in order to meet the required commercial standards through more efficient methods.

Change the channel: CysLoop receptor antagonists from nature

Vertebrate and invertebrate ligand-gated ion channels (LGICs) exhibit significant structural homology and often share ligands. As a result, ligands with activity against one class can be brought to bear against another, including for development as insecticides. Receptor selectivity, metabolism and distribution must then be optimized using chemical synthesis. Here we review natural products (NPs) that ligate and inhibit the Cys-loop family of LGICs, which benefit from the unique physicochemical properties of natural product space but often present a high synthetic burden. Recent advances in chemical synthesis, however, have opened practical entries into these complex structures, several of which are highlighted. © 2020 Society of Chemical Industry.

Structure-Function of Neuronal Nicotinic Acetylcholine Receptor Inhibitors Derived From Natural Toxins

Neuronal nicotinic acetylcholine receptors (nAChRs) are prototypical cation-selective, ligand-gated ion channels that mediate fast neurotransmission in the central and peripheral nervous systems. nAChRs are involved in a range of physiological and pathological functions and hence are important therapeutic targets. Their subunit homology and diverse pentameric assembly contribute to their challenging pharmacology and limit their drug development potential. Toxins produced by an extensive range of algae, plants and animals target nAChRs, with many proving pivotal in elucidating receptor pharmacology and biochemistry, as well as providing templates for structure-based drug design. The crystal structures of these toxins with diverse chemical profiles in complex with acetylcholine binding protein (AChBP), a soluble homolog of the extracellular ligand-binding domain of the nAChRs and more recently the extracellular domain of human α9 nAChRs, have been reported. These studies have shed light on the diverse molecular mechanisms of ligand-binding at neuronal nAChR subtypes and uncovered critical insights useful for rational drug design. This review provides a comprehensive overview and perspectives obtained from structure and function studies of diverse plant and animal toxins and their associated inhibitory mechanisms at neuronal nAChRs.

Supramolecular Nano-Encapsulation of Anabasine Reduced Its Developmental Toxicity in Zebrafish

Anabasine (ANA), a major piperidine alkaloid originally isolated from wild tobacco trees (Nicotiana glauca), has been known to induce serious developmental toxicities such as skeletal deformities in livestock and humans. In this study, we thoroughly investigated the supramolecular nano-encapsulations of ANA by an artificial nanocontainer, cucurbit[7] uril (CB[7]), and examined the influences of the nano-encapsulation on ANA's inherent developmental toxicities on a zebrafish model. We have shown that CB[7] formed 1:1 host-guest inclusion complexes with ANA via a relatively high binding strength [K_a of (7.45 ± 0.31) × 10⁴ M⁻¹] in an aqueous solution, via UV-vis and ¹H nuclear magnetic resonance spectroscopic titrations, as well as isothermal titration calorimetry titration. As a consequence, CB[7] significantly attenuated the developmental toxicity of ANA on zebrafish in vivo. In contrast, for a comparative purpose, β-CD didn't exert any influence on the toxicity of ANA due to its weak binding with ANA, which was not even measurable via either spectroscopic methods or ITC titration. This is the first head-to-head comparison of this pair of nanocontainers, CB[7] and β-CD, on their potential roles in influencing the toxicity of guest molecules and the results suggested that CB[7] could become a more promising functional excipient for reducing the inherent toxicities of active pharmaceutical ingredients, particularly alkaloids that may form relatively strong host-guest binding species with the host.

Lupin (Lupinus spp.) seeds exert anthelmintic activity associated with their alkaloid content

The growing range of drug resistant parasitic nematode populations threatens the sustainability of ruminant farming worldwide. In this context, nutraceuticals, animal feed that provides necessary dietary requirements while ensuring parasite control, could contribute to increase farming sustainability in developed and low resource settings. In this study, we evaluated the anthelmintic potential of lupin seed extracts against the major ruminant trichostrongylids, Haemonchus contortus and Teladorsagia circumcincta. In vitro observations showed that seed extracts from commercially available lupin varieties could significantly but moderately inhibit larval migration. This anthelmintic effect was mediated by the seed alkaloid content and was potent against both fully susceptible and multidrug resistant H. contortus isolates as well as a susceptible T. circumcincta isolate. Analytical chemistry revealed a set of four lupanine and sparteine-derivatives with anthelmintic activity, and electrophysiology assays on recombinant nematode acetylcholine receptors suggested an antagonistic mode of action for lupin alkaloids. An in vivo trial in H. contortus infected lupin-fed ewes and goats failed to demonstrate any direct anthelmintic effect of crude lupin seeds but infected lupin-fed goats suffered significantly less parasite-mediated blood losses. Altogether, our findings suggest that the anthelmintic potential of lupin remains limited. However, the potent alkaloids identified could lead to the development of novel drugs or may be used in combination with current anthelmintics to improve their efficacy.

Animal and plant factors which affect larkspur toxicosis in cattle: Sex, age, breed, and plant chemotype

Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of western North America. Recent research has shown that both plant and animal-based factors are critical in understanding and mitigating larkspur poisoning in cattle. Non-toxicological factors including sex, age, cattle breed, and plant chemotype affect cattle responses to larkspur. For example, Angus heifers are more susceptible to larkspur intoxication than are steers or bulls. Young cattle appear to be more susceptible to larkspur poisoning than mature animals. Beef breeds of cattle are more susceptible to larkspur intoxication than dairy breeds. In addition to animal factors, plant alkaloid composition (chemotype) affects the potential toxicity for cattle because of differences in the ratios and concentrations of highly toxic N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids compared to less lethal non-MSAL-type alkaloids. Animal- and plant-based factors can provide substantial information to inform livestock producers on management to reduce risk and cattle losses to various larkspur species in western North America.

The effect of alkaloid composition of larkspur (Delphinium) species on the intoxication of Angus heifers1

Cattle losses from larkspur (Delphinium spp.) toxicity are a long-term challenge on the rangelands of western North America. In addition to animal factors that affect livestock poisonings, plant alkaloid composition (chemotype) affects the intoxication of cattle because some chemotypes are significantly more toxic. Differences in larkspur chemotype toxicity are due to the ratios of N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids to non-MSAL-type alkaloids and the concentrations of those alkaloids in the plant material. The objective of this study was to compare the responses of 6 Angus heifers to 6 chemotypes of larkspur using a Latin square study design. These Angus heifers from the USDA-ARS, Meat Animal Research Center in Clay Center, NE, were chosen for this research because they are the most larkspur-susceptible cattle observed to date. The 6 heifers were given an oral dose of dried ground larkspur and tested for muscle weakness with an exercise test (i.e., walk time). The 6 chemotypes of larkspur had non-MSAL to MSAL-type alkaloid ratios ranging from 1.4:1 to 6:1 and were administered at an oral dose of 7.5 mg/kg MSAL-type alkaloids BW. There was a treatment effect due to larkspur chemotype (P < 0.0001), and period effects were not significant (P = 0.6). There were also significant correlations between the length of time walking on a dirt track at 5 to 6 km/h, and total alkaloid dose (r = -0.92, P = 0.0045) and alkaloid ratio (r = -0.81, P = 0.0258). Serum alkaloid concentrations at 24 h after dosing were representative of the relative abundance of the alkaloid in the plant material. Results from this work suggest that total alkaloid concentrations in combination with alkaloid ratios can be used together to accurately predict the plant risk component of larkspur poisoning to grazing cattle. Animal factors such as cattle age, breed, and sex must also be considered to comprehensively manage larkspur risk.

Sex-dependent differences for larkspur (Delphinium barbeyi) toxicosis in yearling Angus cattle1

Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of western North America. Results from preliminary experiments have suggested that differences in larkspur toxicity may exist between heifers and bulls. The objective of this study was to compare the physiological responses of yearling Angus heifers, steers, and bulls with a standardized dose of Delphinium barbeyi and to test the hypothesis that the response is sex dependent. Clinical signs of intoxication, including muscle coordination and function, were measured 24 h after oral dosing with larkspur by walking the cattle at a pace of 5 to 6 km h-1 for up to 40 min on an oval dirt track. Due to the experimental methods used, the variation in susceptibility to larkspur was not quantifiable for walking times of 0 or 40 min or more. Larkspur susceptible animals that were not able to walk (0 min; 36% of the animals) or larkspur resistant animals that walked the entire test period of 40 min (9% of the animals) resulted in censored or truncated data. The statistical methods (censReg and lmec) were used to adjust for data truncation or censoring. The heifers were only able to walk -8.9 ± 3.9 min (65.5% censored on the left) compared with 13.2 ± 3.7 min for bulls and 15.9 ± 2.7 min for steers. When heifers were compared with bulls and steers together, heifers walked 23.4 ± 4.5 min less (P < 0.0001). Serum alkaloid concentrations were measured immediately before walking, and deltaline concentrations averaged 266 ± 28, 131 ± 20, and 219 ± 28 ng mL-1 for all heifers, steers, and bulls, respectively, and serum methyllycaconitine concentrations averaged 660 ± 46, 397 ± 32, and 612 ± 34 ng mL-1 for all heifers, steers, and bulls, respectively. The relative risk of a zero walk time for yearling heifers is 330% that of yearling bulls (P = 0.0008). These results suggest that yearling Angus heifers are more susceptible to larkspur intoxication and, when possible, heifers should be kept from grazing larkspur-infested rangelands as a simple management tool to reduce the risk of fatal poisoning.

Complete inhibition of fetal movement in the day 40 pregnant goat model by the piperidine alkaloid anabasine but not related alkaloids

Four chemically similar alkaloids, anabasine, anabaseine, epibatidine and dimethylphenylpiperazinium (DMPP), are potent nicotinic acetylcholine receptor agonists of fetal muscle nicotinic acetylcholine receptors in human TE-671 cells. Based on results with these cells, we hypothesized that the alkaloids would completely inhibit ultrasound-monitored fetal movement in a goat model. Different, single doses of anabasine, anabaseine, epibatidine, DMPP, or saline control were administered I.V. to pregnant goats on day 40 of gestation and the number of fetal movements per 5 min sample was measured by ultrasound at times 0, 0.5, 1, 2, 4 and 8 h. The differences among does in fetal movements were more consistent at dosing and following recovery for doses of anabasine above 0.125 mg/kg compared to the other compounds and dosages. Anabasine actions were dose-dependent with an IC₅₀ value of ∼0.1 mg/kg, and, at a dose of 0.8 mg/kg, completely inhibited fetal movement for 1.5 h after dosing. Anabaseine, epibatidine, and DMPP failed to completely inhibit fetal movement in day 40 pregnant goats at doses predicted to be effective. These results suggest that while experiments with TE-671 cells provide valuable information and predictions of the actions of plant alkaloids on fetal movement, in vivo experiments are still required in order to determine the ability of an alkaloid to inhibit fetal movement in livestock species. Moreover, other pharmacological properties such as receptor differences between mammalian species and differences in the pharmacokinetic properties of the alkaloids also are likely to weaken teratologic predictions based solely on the in vitro data.

Inhibition on cholinesterase and tyrosinase by alkaloids and phenolics from Aristotelia chilensis leaves

It is reported in this study the effect of isolates from leaves of Aristotelia chilensis as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes. The aim of the paper was to evaluate the activity of A. chilensis towards different enzymes. In addition to pure compounds, extracts rich in alkaloids and phenolics were tested. The most active F5 inhibited AChE (79.5% and 89.8% at 10.0 and 20.0 μg/mL) and against BChE (89.5% and 97.8% at 10.0 and 20.0 μg/mL), showing a strong mixed-type inhibition against AChE and BChE. F3 (a mixture of flavonoids and phenolics acids), showed IC₅₀ of 90.7 and 59.6 μg/mL of inhibitory activity against AChE and BChE, inhibiting the acetylcholinesterase competitively. Additionally, F3 showed and high potency as tyrosinase inhibitor with IC₅₀ at 8.4 μg/mL. Sample F4 (anthocyanidins and phenolic composition) presented a complex, mixed-type inhibition of tyrosinase with a IC₅₀ of 39.8 μg/mL. The findings in this investigation show that this natural resource has a strong potential for future research in the search of new phytotherapeutic treatments for cholinergic deterioration ailments avoiding the side effects of synthetic drugs. This is the first report as cholinesterases and tyrosinase inhibitors of alkaloids and phenolics from A. chilensis leaves.

Anagyrine desensitization of peripheral nicotinic acetylcholine receptors. A potential biomarker of quinolizidine alkaloid teratogenesis in cattle

Anagyrine, a teratogenic quinolizidine alkaloid found in Lupinus spp., is proposed to undergo metabolism by pregnant cattle to a piperidine alkaloid which inhibits fetal movement, the putative mechanism behind crooked calf syndrome. The objective of this study was to test the hypothesis that anagyrine but not lupanine or sparteine can directly, without metabolism, desensitize nicotinic acetylcholine receptors (nAChR) in a cell culture model. SH-SY5Y cells expressing autonomic nAChR, and TE-671 cells expressing fetal muscle-type nAChR were exposed to lupine alkaloids or Dimethylphenylpiperazinium (DMPP) in log₁₀ molar increments from 10nM to 100μM and then to a fixed concentration of acetylcholine (ACh) (10μM for SH-SY5Y cells and 1μM for TE-671 cells) and the responses measured with a membrane potential sensing dye to assess nAChR activation and desensitization. The selective ganglionic nAChR agonist DMPP used as a positive control, was a potent activator and desensitizer of nAChR expressed by SH-SY5Y cells. Lupanine was a weak agonist and desensitizer in SH-SY5Y cells and sparteine was without effect. Anagyrine acted as a partial agonist in both cell lines with EC₅₀ values of 4.2 and 231μM in SH-SY5Y and TE-671 cells, respectively. Anagyrine was a desensitizer of nAChR with DC₅₀ values of 6.9 and 139μM in SH-SY5Y and TE-671 cells, respectively. These results confirm the hypothesis that anagyrine is a potent and effective desensitizer of nAChR, and that anagyrine can directly, without metabolism, desensitize nAChR. Moreover, serum anagyrine concentrations may be a potential biomarker for lupine teratogenicity in cattle.

Intravenous Poison Hemlock Injection Resulting in Prolonged Respiratory Failure and Encephalopathy

BACKGROUND

Poison hemlock (Conium maculatum) is a common plant with a significant toxicity. Data on this toxicity is sparse as there have been few case reports and never a documented poisoning after intravenous injection.

OBJECTIVES

We present a case of intravenous poison hemlock injection encountered in the emergency department.

CASE REPORT

We describe a 30-year-old male who presented to the emergency department after a brief cardiac arrest after injecting poison hemlock. The patient had return of spontaneous circulation in the emergency department but had prolonged muscular weakness and encephalopathy later requiring tracheostomy.

CONCLUSION

Intravenous injection of poison hemlock alkaloids can result in significant toxicity, including cardiopulmonary arrest, prolonged weakness, and encephalopathy.

Digestive system damage in acute poisoning and treatment strategy

Acute intoxication is a common critical clinical condition. Poisoning patients tend to have an urgent onset, critical illness and rapid progression. If timely and reasonable treatment is not given, there will be a serious threat to patients' life. Drugs, alcohol, pesticides, and poisonous chemicals are clinically common toxic substances, and oral suicide is a major cause of poisoning. Therefore, suicidal patients absorb poison mainly through the digestive tract, and digestive system damage is common and serious. Awareness of digestive system damage in patients with acute poisoning and treatment measures has important clinical significance for improving the overall prognosis of these patients. This paper discusses the latest research progress in understanding digestive system damage in acute poisoning and treatment strategy.

Activation and Desensitization of Peripheral Muscle and Neuronal Nicotinic Acetylcholine Receptors by Selected, Naturally-Occurring Pyridine Alkaloids

Teratogenic alkaloids can cause developmental defects due to the inhibition of fetal movement that results from desensitization of fetal muscle-type nicotinic acetylcholine receptors (nAChRs). We investigated the ability of two known teratogens, the piperidinyl-pyridine anabasine and its 1,2-dehydropiperidinyl analog anabaseine, to activate and desensitize peripheral nAChRs expressed in TE-671 and SH-SY5Y cells. Activation-concentration response curves for each alkaloid were obtained in the same multi-well plate. To measure rapid desensitization, cells were first exposed to five potentially-desensitizing concentrations of each alkaloid in log₁₀ molar increments from 10 nM to 100 µM and then to a fixed concentration of acetylcholine (ACh), which alone produces near-maximal activation. The fifty percent desensitization concentration (DC₅₀) was calculated from the alkaloid concentration-ACh response curve. Agonist fast desensitization potency was predicted by the agonist potency measured in the initial response. Anabaseine was a more potent desensitizer than anabasine. Relative to anabaseine, nicotine was more potent to autonomic nAChRs, but less potent to the fetal neuromuscular nAChRs. Our experiments have demonstrated that anabaseine is more effective at desensitizing fetal muscle-type nAChRs than anabasine or nicotine and, thus, it is predicted to be more teratogenic.

Novel multifunctional pharmacology of lobinaline, the major alkaloid from Lobelia cardinalis

In screening a library of plant extracts from ~1000 species native to the Southeastern United States, Lobelia cardinalis was identified as containing nicotinic acetylcholine receptor (nicAchR) binding activity which was relatively non-selective for the α4β2- and α7-nicAchR subtypes. This nicAchR binding profile is atypical for plant-derived nicAchR ligands, the majority of which are highly selective for α4β2-nicAchRs. Its potential therapeutic relevance is noteworthy since agonism of α4β2- and α7-nicAchRs is associated with anti-inflammatory and neuroprotective properties. Bioassay-guided fractionation of L. cardinalis extracts led to the identification of lobinaline, a complex binitrogenous alkaloid, as the main source of the unique nicAchR binding profile. Purified lobinaline was a potent free radical scavenger, displayed similar binding affinity at α4β2- and α7-nicAchRs, exhibited agonist activity at nicAchRs in SH-SY5Y cells, and inhibited [(3)H]-dopamine (DA) uptake in rat striatal synaptosomes. Lobinaline significantly increased fractional [(3)H] release from superfused rat striatal slices preloaded with [(3)H]-DA, an effect that was inhibited by the non-selective nicAchR antagonist mecamylamine. In vivo electrochemical studies in urethane-anesthetized rats demonstrated that lobinaline locally applied in the striatum significantly prolonged clearance of exogenous DA by the dopamine transporter (DAT). In contrast, lobeline, the most thoroughly investigated Lobelia alkaloid, is an α4β2-nicAchR antagonist, a poor free radical scavenger, and is a less potent DAT inhibitor. These previously unreported multifunctional effects of lobinaline make it of interest as a lead to develop therapeutics for neuropathological disorders that involve free radical generation, cholinergic, and dopaminergic neurotransmission. These include neurodegenerative conditions, such as Parkinson's disease, and drug abuse.

Selection of Annonaceae Species for the Control of Spodoptera frugiperda (Lepidoptera: Noctuidae) and Metabolic Profiling of Duguetia lanceolata Using Nuclear Magnetic Resonance Spectroscopy

This study was performed to investigate the activity of 19 dichloromethane-soluble fractions obtained from the methanolic extracts of 10 Annonaceae species against the fall armyworm, Spodoptera frugiperda (J. E. Smith). The stem bark of Duguetia lanceolata A. St.-Hil. showed the highest insecticidal activity, with a median lethal time (LT50) of 61.4 h and a median lethal concentration (LC50) of 946.5 µg/ml of diet. The dichloromethane-soluble fractions from six D. lanceolata specimens were subjected to evaluation of their activities against S. frugiperda and metabolomic analysis using hydrogen (1H) nuclear magnetic resonance (NMR) spectroscopy. Although all of the samples affected S. frugiperda mortality, their insecticidal activities varied according to the sample used in the experiments. Using partial least squares regression of the results, the D. lanceolata specimens were grouped according to their metabolite profile and insecticidal activity. A detailed analysis via uni- and bidimensional NMR spectroscopy showed that the peaks in the 1H NMR spectra associated with increased insecticidal activity could be attributed to 2,4,5-trimethoxystyrene, which suggests that this substance is involved in the insecticidal activity of the stem bark fraction of D. lanceolata.

Pyrrolizidine alkaloids from Solenanthus lanatus DC. with acetylcholinesterase inhibitory activity

The whole plant ethanolic extract of Solenanthus lanatus was used for the isolation of acetylcholinesterase inhibitors. A new pyrrolizidine alkaloid, 7-O-angeloylechinatine N-oxide, 1, was isolated together with three known compounds of the same class (3'-O-acetylheliosupine N-oxide, 2, heliosupine N-oxide, 3, and heliosupine, 4), by bioassay-guided approach. Their structures were elucidated by spectroscopic methods. All the isolated compounds showed inhibition activity against the AChE, with IC₅₀ 0.53-0.60 mM.

Differences between Angus and Holstein cattle in the Lupinus leucophyllus induced inhibition of fetal activity

Calves with congenital defects born to cows that have grazed teratogenic Lupinus spp. during pregnancy can suffer from what is termed crooked calf syndrome. Crooked calf syndrome defects include cleft palate, spinal column defects and limb malformations formed by alkaloid-induced inhibition of fetal movement. In this study, we tested the hypothesis that there are differences in fetal activity of fetuses carried by Holstein verses Angus heifers orally dosed with 1.1 g/kg dried ground Lupinus leucophyllus. Fetal activity was monitored via transrectal ultrasonography and maternal serum was analyzed for specific lupine alkaloids. There were more (P < 0.05) movements in fetuses of Holstein heifers than those in Angus heifers at eight and 12 h after oral dosing. In addition to serum alkaloid toxicokinetic differences, the Holstein heifers had significantly lower serum concentrations of anagyrine at 2, 4, and 8 h after oral dosing than Angus heifers. Holstein heifers also had significantly greater serum concentrations of lupanine at 12, 18 and 24 h after dosing than the Angus heifers. These results suggest that there are breed differences in susceptibility to lupine-induced crooked calf syndrome. These differences may also be used to discover genetic markers that identify resistant animals, thus facilitating selective breeding of resistant herds.

Biomolecular recognition of antagonists by α7 nicotinic acetylcholine receptor: Antagonistic mechanism and structure-activity relationships studies

As the key constituent of ligand-gated ion channels in the central nervous system, nicotinic acetylcholine receptors (nAChRs) and neurodegenerative diseases are strongly coupled in the human species. In recently years the developments of selective agonists by using nAChRs as the drug target have made a large progress, but the studies of selective antagonists are severely lacked. Currently these antagonists rest mainly on the extraction of partly natural products from some animals and plants; however, the production of these crude substances is quite restricted, and artificial synthesis of nAChR antagonists is still one of the completely new research fields. In the context of this manuscript, our primary objective was to comprehensively analyze the recognition patterns and the critical interaction descriptors between target α7 nAChR and a series of the novel compounds with potentially antagonistic activity by means of virtual screening, molecular docking and molecular dynamics simulation, and meanwhile these recognition reactions were also compared with the biointeraction of α7 nAChR with a commercially natural antagonist - methyllycaconitine. The results suggested clearly that there are relatively obvious differences of molecular structures between synthetic antagonists and methyllycaconitine, while the two systems have similar recognition modes on the whole. The interaction energy and the crucially noncovalent forces of the α7 nAChR-antagonists are ascertained according to the method of Molecular Mechanics/Generalized Born Surface Area. Several amino acid residues, such as B/Tyr-93, B/Lys-143, B/Trp-147, B/Tyr-188, B/Tyr-195, A/Trp-55 and A/Leu-118 played a major role in the α7 nAChR-antagonist recognition processes, in particular, residues B/Tyr-93, B/Trp-147 and B/Tyr-188 are the most important. These outcomes tally satisfactorily with the discussions of amino acid mutations. Based on the explorations of three-dimensional quantitative structure-activity relationships, the structure-antagonistic activity relationships of antagonists and the characteristics of α7 nAChR-ligand recognitions were received a reasonable summary as well. These attempts emerged herein would not only provide helpful guidance for the design of α7 nAChR antagonists, but shed new light on the subsequent researches in antagonistic mechanism.

A study on embryonic death in goats due to Nicotiana glauca ingestion

Numerous plants are known to be teratogenic in livestock. In addition to causing malformations, several plants can also cause embryonic death. These losses decrease the reproductive efficiency of animals exposed to these plants. The aim of this study was to determine if teratogenic plants such as lupines or tobaccos cause embryonic losses. A goat model using the plant Nicotiana glauca was used in this study, as this model has been used to characterize the mechanism of Lupinus, Conium, and Nicotiana-induced terata. Four groups of goats were dosed from gestational day 1-10, 11-20, 21-30, and 31-40. Goats were evaluated via ultrasound imaging for pregnancy after completion of the dosing regimen and kids were evaluated for malformations at the time of parturition. Overall, there was no evidence from this study that N. glauca (anabasine) at this dose (2 g/kg/day) would cause embryonic losses in goats. However, the dose of N. glauca used in this study was at the lower threshold that would be expected to produce terata. Therefore it is possible that higher doses of anabasine could cause embryonic loss. Further work is also needed to characterize the kinetic profile of anabasine, and other teratogenic alkaloids, in the fetal compartments.

Biopesticides from plants: Calceolaria integrifolia s.l

The effects of persistent organic pollutants (POPs) on humans and biodiversity are multiple and varied. Nowadays environmentally-friendly pesticides are strongly preferred to POPs. It is noteworthy that the crop protection role of pesticides and other techniques, i.e. biopesticides, plant extracts, prevention methods, organic methods, evaluation of plant resistance to certain pests under an integrated pest management (IPM), could improve the risks and benefits which must be assessed on a sound scientific basis. For this directive it is crucial to bring about a significant reduction in the use of chemical pesticides, not least through the promotion of sustainable alternative solutions such as organic farming and IPM. Biopesticides are derived from natural materials such as animals, plants, bacteria, and certain minerals. Most of them are biodegradable in relatively short periods of time. On this regard, substances from Calceolaria species emerge as a strong alternative to the use of POPs. The American genus Calceolaria species are regarded both as a notorious weeds and popular ornamental garden plants. Some have medicinal applications. Other taxa of Calceolaria are toxic to insects and resistant to microbial attack. These properties are probably associated with the presence of terpenes, iridoids, flavonoids, naphthoquinones and phenylpropanoids previously demonstrated to have interesting biological activities. In this article a comprehensive evaluation of the potential utilization of Calceolaria species as a source of biopesticides is made. The chemical profile of selected members of the Chilean Calceolaria integrifolia sensu lato complex represents a significant addition to previous studies. New secondary metabolites were isolated, identified and tested for their antifeedant, insect growth regulation and insecticidal activities against Spodoptera frugiperda and Drosophila melanogaster. These species serve as a model of insect pests using conventional procedures. Additionally, bactericidal and fungicidal activity were determined. Dunnione mixed with gallic acid was the most active fungistatic and fungicidal combination encountered. Several compounds as isorhamnetin, combined with ferulic and gallic acid quickly reduced cell viability, but cell viability was recovered quickly and did not differ from that of the control. The effect of these mixtures on cultures of Aspergillus niger, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes, was sublethal. However, when fungistatic isorhamnetin and dunnione were combined with sublethal amounts of both ferulic and gallic acid, respectively, strong fungicidal activity against theses strains was observed. Thus, dunnione combined with gallic acid completely restricted the recovery of cell viability. This apparent synergistic effect was probably due to the blockade of the recovery process from induced-stress. The same series of phenolics (iridoids, flavonoids, naphthoquinones and phenylpropanoids) were also tested against the Gram-negative bacteria Escherichia coli, Enterobacter agglomerans, and Salmonella typhi, and against the Gram-positive bacteria Bacillus subtilis, Sarcinia lutea, and Staphylococcus aureus and their effects compared with those that of kanamycin. Mixtures of isorhamnetin/dunnione/kaempferol/ferulic/gallic acid in various combinations were found to have the most potent bactericidal and fungicidal activity with MFC between 10 and 50 μg/ml. Quercetin was found to be the most potent fungistatic single compound with an MIC of 15 µg/ml. A time-kill curve study showed that quercetin was fungicidal against fungi assayed at any growth stage. This antifungal activity was slightly enhanced by combination with gallic acid. The primary antifungal action of the mixtures assayed likely comes from their ability to act as nonionic surfactants that disrupt the function of native membrane-associated proteins. Hence, the antifungal activity of isorhamnetin and other O-methyl flavonols appears to be mediated by biophysical processes. Maximum activity is obtained when the balance between hydrophilic and hydrophobic portions of the molecules of the mixtures becomes the most appropriate. Diterpenes, flavonoids, phenylpropanoids, iridoids and phenolic acids were identified by chromatographic procedures (HPLC-DAD), ESI-MS, and NMR hyphenated techniques.

Studies on the teratogenicity of anabasine in a rat model

A number of plant toxins have been shown to be teratogenic to livestock. The teratogenic action of some of these alkaloids is mediated by nicotinic acetylcholine receptors (nAChR). However, for many of these alkaloids it is difficult to obtain sufficient quantities of individual alkaloids to perform teratology studies in livestock species. Therefore the objective of this study was to determine if a rat model can be utilized to characterize the teratogenic nature of individual plant toxins that are nAChR agonists. In this study, we evaluated the teratogenicity of anabasine by feeding pregnant rats anabasine-containing rodent chow from gestational day (GD) 6-21. On GD21, the dams were euthanized and the gravid uteri were removed. The gravid uteri and individual pups were weighed. The pups were evaluated for bone malformations including cleft palate and scoliosis. Overall, the results of this study suggest that the rat is not a good model to study the teratogenicity of plant toxins that are nAChR agonists. It is possible that in the rat model, anabasine administered orally via the chow may not result in sufficient reduction in fetal movement to cause the significant malformations observed in livestock species.

Bioactive marine drugs and marine biomaterials for brain diseases

Marine invertebrates produce a plethora of bioactive compounds, which serve as inspiration for marine biotechnology, particularly in drug discovery programs and biomaterials development. This review aims to summarize the potential of drugs derived from marine invertebrates in the field of neuroscience. Therefore, some examples of neuroprotective drugs and neurotoxins will be discussed. Their role in neuroscience research and development of new therapies targeting the central nervous system will be addressed, with particular focus on neuroinflammation and neurodegeneration. In addition, the neuronal growth promoted by marine drugs, as well as the recent advances in neural tissue engineering, will be highlighted.