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Metabolites Apr 2023Alkaloids are the most diversified nitrogen-containing secondary metabolites, having antioxidant and antimicrobial properties, and are extensively used in... (Review)
Review
Alkaloids are the most diversified nitrogen-containing secondary metabolites, having antioxidant and antimicrobial properties, and are extensively used in pharmaceuticals to treat different types of cancer. Nicotiana serves as a reservoir of anti-cancer alkaloids and is also used as a model plant for the de novo synthesis of various anti-cancer molecules through genetic engineering. Up to 4% of the total dry weight of Nicotiana was found to be composed of alkaloids, where nicotine, nornicotine, anatabine, and anabasine are reported as the dominant alkaloids. Additionally, among the alkaloids present in Nicotiana, β-carboline (Harmane and Norharmane) and Kynurenines are found to show anti-tumor effects, especially in the cases of colon and breast cancers. Creating new or shunting of existing biosynthesis pathways in different species of Nicotiana resulted in de novo or increased synthesis of different anti-tumor molecules or their derivatives or precursors including Taxadiane (~22.5 µg/g), Artemisinin (~120 μg/g), Parthenolide (~2.05 ng/g), Costunolide (~60 ng/g), Etoposide (~1 mg/g), Crocin (~400 µg/g), Catharanthine (~60 ng/g), Tabersonine (~10 ng/g), Strictosidine (~0.23 mg/g), etc. Enriching the precursor pool, especially Dimethylallyl Diphosphate (DMAPP), down-regulating other bi-product pathways, compartmentalization or metabolic shunting, or organelle-specific reconstitution of the precursor pool, might trigger the enhanced accumulation of the targeted anti-cancer alkaloid in .
PubMed: 37233664
DOI: 10.3390/metabo13050623 -
F1000Research 2015Secondary metabolites in floral nectar have been shown to reduce parasite load in two common bumble bee species. Previous studies on the effects of nectar secondary...
Secondary metabolites in floral nectar have been shown to reduce parasite load in two common bumble bee species. Previous studies on the effects of nectar secondary metabolites on parasitized bees have focused on single compounds in isolation; however, in nature, bees are simultaneously exposed to multiple compounds. We tested for interactions between the effects of two alkaloids found in the nectar of Nicotiana spp. plants, nicotine and anabasine, on parasite load and mortality in bumble bees ( Bombus impatiens) infected with the intestinal parasite Crithidia bombi. Adult worker bees inoculated with C. bombi were fed nicotine and anabasine diet treatments in a factorial design, resulting in four nectar treatment combinations: 2 ppm nicotine, 5 ppm anabasine, 2ppm nicotine and 5 ppm anabasine together, or a control alkaloid-free solution. We conducted the experiment twice: first, with bees incubated under variable environmental conditions ('Variable'; temperatures varied from 10-35°C with ambient lighting); and second, under carefully controlled environmental conditions ('Stable'; 27°C incubator, constant darkness). In 'Variable', each alkaloid alone significantly decreased parasite loads, but this effect was not realized with the alkaloids in combination, suggesting an antagonistic interaction. Nicotine but not anabasine significantly increased mortality, and the two compounds had no interactive effects on mortality. In 'Stable', nicotine significantly increased parasite loads, the opposite of its effect in 'Variable'. While not significant, the relationship between anabasine and parasite loads was also positive. Interactive effects between the two alkaloids on parasite load were non-significant, but the pattern of antagonistic interaction was similar to that in the variable experiment. Neither alkaloid, nor their interaction, significantly affected mortality under controlled conditions. Our results do not indicate synergy between Nicotiana nectar alkaloids; however, they do suggest a complex interaction between secondary metabolites, parasites, and environmental variables, in which secondary metabolites can be either toxic or medicinal depending on context.
PubMed: 26998225
DOI: 10.12688/f1000research.6870.2 -
NPJ Biofilms and Microbiomes Nov 2020Sunbirds feed on tobacco tree nectar which contains toxic nicotine and anabasine secondary metabolites. Our aim was to understand the effect of nicotine and anabasine on...
Sunbirds feed on tobacco tree nectar which contains toxic nicotine and anabasine secondary metabolites. Our aim was to understand the effect of nicotine and anabasine on the gut microbiota composition of sunbirds. Sixteen captive sunbirds were randomly assigned to two diets: artificial nectar either with (treatment) or without (control) added nicotine and anabasine. Excreta were collected at 0, 2, 4 and 7 weeks of treatment and samples were processed for bacterial culture and high-throughput amplicon sequencing of the 16S rRNA gene. The gut microbiome diversity of the treated and control birds changed differently along the seven-week experiment. While the diversity decreased in the control group along the first three samplings (0, 2 and 4 weeks), it increased in the treatment group. The microbiota composition analyses demonstrated that a diet with nicotine and anabasine, significantly changed the birds' gut microbiota composition compared to the control birds. The abundance of nicotine- and anabasine- degrading bacteria in the excreta of the treated birds, was significantly higher after four and seven weeks compared to the control group. Furthermore, analysis of culturable isolates, including Lactococcus, showed that sunbirds' gut-associated bacteria were capable of degrading nicotine and anabasine, consistent with their hypothesised role as detoxifying and nutritional symbionts.
Topics: Anabasine; Animal Feed; Animals; Bacteria; DNA, Bacterial; DNA, Ribosomal; Feces; Gastrointestinal Microbiome; Nicotine; Passeriformes; Phylogeny; Plant Extracts; Pyridines; RNA, Ribosomal, 16S; Secondary Metabolism; Sequence Analysis, DNA; Nicotiana
PubMed: 33188208
DOI: 10.1038/s41522-020-00161-9 -
JMIR Research Protocols Oct 2022Tobacco harm reduction (THR) aims to reduce the health burden of cigarettes by encouraging smokers to switch to using alternative tobacco or nicotine products. Nicotine...
BACKGROUND
Tobacco harm reduction (THR) aims to reduce the health burden of cigarettes by encouraging smokers to switch to using alternative tobacco or nicotine products. Nicotine pouches (NPs) are smokeless, tobacco-free, oral products that may be beneficial as part of a THR strategy.
OBJECTIVE
This 2-center, cross-sectional confinement study conducted in Denmark and Sweden aimed to determine whether biomarkers of exposure (BoEs) to tobacco toxicants and biomarkers of potential harm (BoPHs) in exclusive users of NPs show favorable differences compared with current smokers.
METHODS
Participants were healthy NP users (target n=100) and current, former, or never smokers (target n=40 each), as confirmed by urinary cotinine and exhaled carbon monoxide concentrations. During a 24-hour confinement period, participants were asked to use their usual product (NP or cigarette) as normal, and BoEs and BoPHs were measured in blood and 24-hour urine samples, with compliance determined using anabasine, anatabine, and N-(2-cyanoethyl)valine. BoEs and BoPHs were compared between NP users and current, former, and never smokers. Urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (BoE to nicotine-derived nitrosamine ketone) and urinary 8-epi-prostaglandin F2α type III, exhaled nitric oxide, blood carboxyhemoglobin, white blood cell count, soluble intercellular adhesion molecule-1, and high-density lipoprotein cholesterol (BoPHs) were evaluated as primary outcomes. Other measures included urinary 11-dehydrothromboxane B2, forced expiratory volume, carotid intima-media thickness, self-reported quality of life, and oral health.
RESULTS
The results of this study were received in mid-2022 and will be published in late 2022 to early 2023.
CONCLUSIONS
The results of this study will provide information on toxicant exposure and biomarkers associated with the development of smoking-related diseases among users of NPs compared with smokers, as well as on the potential role of NPs in THR.
TRIAL REGISTRATION
International Standard Randomised Controlled Trial Number (ISRCTN) ISRCTN16988167; https://www.isrctn.com/ISRCTN16988167.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)
DERR1-10.2196/39785.
PubMed: 36201395
DOI: 10.2196/39785 -
Food and Chemical Toxicology : An... Aug 2021Mitochondria are among the first responders to various stress factors that challenge cell and tissue homeostasis. Various plant alkaloids have been investigated for...
Mitochondria are among the first responders to various stress factors that challenge cell and tissue homeostasis. Various plant alkaloids have been investigated for their capacity to modulate mitochondrial activities. In this study, we used isolated mitochondria from mouse brain and liver tissues to assess nicotine, anatabine and anabasine, three alkaloids found in tobacco plant, for potential modulatory activity on mitochondrial bioenergetics parameters. All alkaloids decreased basal oxygen consumption of mouse brain mitochondria in a dose-dependent manner without any effect on the ADP-stimulated respiration. None of the alkaloids, at 1 nM or 1.25 μM concentrations, influenced the maximal rate of swelling of brain mitochondria. In contrast to brain mitochondria, 1.25 μM anatabine, anabasine and nicotine increased maximal rate of swelling of liver mitochondria suggesting a toxic effect. Only at 1 mM concentration, anatabine slowed down the maximal rate of Ca-induced swelling and increased the time needed to reach the maximal rate of swelling. The observed mitochondrial bioenergetic effects are probably mediated through a pathway independent of nicotinic acetylcholine receptors, as quantitative proteomic analysis could not confirm their expression in pure mitochondrial fractions isolated from mouse brain tissue.
Topics: Alkaloids; Animals; Brain; Energy Metabolism; Membrane Potential, Mitochondrial; Mice; Mitochondria; Plants; Proteomics; Receptors, Nicotinic
PubMed: 34089800
DOI: 10.1016/j.fct.2021.112316 -
Chemical Research in Toxicology Mar 2016Nicotine is the most abundant alkaloid in tobacco accounting for 95% of the alkaloid content. There are also several minor tobacco alkaloids; among these are...
Nicotine is the most abundant alkaloid in tobacco accounting for 95% of the alkaloid content. There are also several minor tobacco alkaloids; among these are nornicotine, anatabine, and anabasine. We developed and applied a 96 well plate-based capillary LC-tandem mass spectrometry method for the analysis of nornicotine, anatabine, and anabasine in urine. The method was validated with regard to accuracy and precision. Anabasine was quantifiable to low levels with a limit of quantitation (LOQ) of 0.2 ng/mL even when nicotine, which is isobaric, is present at concentrations >2500-fold higher than anabasine. This attribute of the method is important since anatabine and anabasine in urine have been proposed as biomarkers of tobacco use for individuals using nicotine replacement therapies. In the present study, we analyzed the three minor tobacco alkaloids in urine from 827 smokers with a wide range of tobacco exposures. Nornicotine (LOQ 0.6 ng/mL) was detected in all samples, and anatabine (LOQ, 0.15 ng/mL) and anabasine were detected in 97.7% of the samples. The median urinary concentrations of nornicotine, anatabine, and anabasine were 98.9, 4.02, and 5.53 ng/mL. Total nicotine equivalents (TNE) were well correlated with anatabine (r(2) = 0.714) and anabasine (r(2) = 0.760). TNE was most highly correlated with nornicotine, which is also a metabolite of nicotine. Urine samples from a subset of subjects (n = 110) were analyzed for the presence of glucuronide conjugates by quantifying any increase in anatabine and anabasine concentrations after β-glucuronidase treatment. The median ratio of the glucuronidated to free anatabine was 0.74 (range, 0.1 to 10.9), and the median ratio of glucuronidated to free anabasine was 0.3 (range, 0.1 to 2.9). To our knowledge, this is the largest population of smokers for whom the urinary concentrations of these three tobacco alkaloids has been reported.
Topics: Adolescent; Alkaloids; Anabasine; Chromatography, High Pressure Liquid; Humans; Molecular Structure; Nicotine; Pyridines; Smoking; Tandem Mass Spectrometry; Nicotiana
PubMed: 26825008
DOI: 10.1021/acs.chemrestox.5b00521 -
Pharmacology, Biochemistry, and Behavior Aug 2021Zebrafish provide a valuable emerging complementary model for neurobehavioral research. They offer a powerful way to screen for the potential therapeutic effects of...
Zebrafish provide a valuable emerging complementary model for neurobehavioral research. They offer a powerful way to screen for the potential therapeutic effects of neuroactive drugs. A variety of behavioral tests for zebrafish have been developed and validated for assessing neurobehavioral function. The novel tank diving test is a straightforward, reproducible way of measuring anxiety-like behavior in zebrafish. When introduced into a novel tank, zebrafish normally dive to the bottom of the tank and then gradually explore the higher levels of the water column as time progresses. Buspirone is an effective anxiolytic drug in humans, which has been found, with acute administration, to reduce this anxiety-like response in zebrafish. The current study used the zebrafish model to evaluate the potential anxiolytic effects of alkaloids, commonly found in Solanaceae plants, with known neuropharmacology relevant to mood regulation. In line with previous findings, acute treatment with anxiolytic positive controls buspirone and the plant alkaloid nicotine reduced the anxiety-like diving response in the zebrafish novel tank diving test. Further, both buspirone and nicotine continued to produce anxiolytic-like effects in zebrafish after 5 days of exposure. In the same treatment paradigm, the effects of five other alkaloids-cotinine, anatabine, anabasine, harmane, and norharmane-were investigated. Cotinine, the major metabolite of nicotine, also caused anxiolytic-like effects, albeit at a dose higher than the effective dose of nicotine. Nicotine's anxiolytic-like effect was not shared by the other nicotinic alkaloids, anabasine and anatabine, or by the naturally present monoamine oxidase inhibitors harmane and norharmane. We conclude that nicotine uniquely induces anxiolytic-like effects after acute and subchronic treatment in zebrafish. The zebrafish model with the novel tank diving test could be a useful complement to rodent models for screening candidate compounds for anxiolytic effects in nonclinical studies.
Topics: Alkaloids; Anabasine; Animals; Anti-Anxiety Agents; Anxiety; Behavior, Animal; Buspirone; Carbolines; Cotinine; Disease Models, Animal; Female; Harmine; Humans; Male; Nicotine; Pyridines; Solanaceae; Zebrafish
PubMed: 34197843
DOI: 10.1016/j.pbb.2021.173223 -
The Journal of Pharmacology and... Mar 2014Nicotine was recently shown to engender d-methamphetamine (MA)-like discriminative-stimulus effects in rats, which may be indicative of shared psychomotor stimulant...
Nicotine was recently shown to engender d-methamphetamine (MA)-like discriminative-stimulus effects in rats, which may be indicative of shared psychomotor stimulant properties. To further investigate such overlapping discriminative-stimulus effects, nicotinic agonists varying in efficacy and selectivity were studied in squirrel monkeys that discriminated a moderate intramuscular dose of MA (0.1 mg/kg) from vehicle. These included α4β2-selective ligands that may vary in efficacy from relatively high [nicotine, (+)- and (-)-epibatidine] to relatively low [isoarecolone, varenicline, (-)-cytisine, (-)-lobeline] and the α7-selective ligands anabaseine and anabasine. Results show that nicotine, (+)-epibatidine, and (-)-epibatidine substituted fully for MA, whereas the highest doses of other nicotinic agonists produced intermediate levels of MA-like effects (isoarecolone, anabaseine, anabasine, and varenicline) or did not substitute for MA [(-)-cytisine and (-)-lobeline]. The relative potencies of nicotinic agonists, based on effective dose50 (ED50) values, corresponded more closely with their relative affinities at α4β2 than at α7 receptors. Regardless of selectivity or efficacy, nicotinic agonists also were observed to produce untoward effects, including salivation and emesis during or after experimental sessions. In pretreatment studies, the α4β2-selective antagonist dihydro-β-erythroidine hydrobromide (DHβE) (0.032 and 0.1 mg/kg) and the partial agonists varenicline (0.0032-0.1 mg/kg) and (-)-cytisine (0.032 and 0.1 mg/kg) surmountably antagonized (>10-fold rightward shift) nicotine's MA-like effects but were ineffective in blocking nicotine's emetic effects. Overall, our results show that 1) MA-like discriminative-stimulus effects of nicotinic agonists likely are mediated through α4β2 nicotinic acetylcholine receptor actions, and 2) nicotinic α4β2 partial agonists, like the nicotinic antagonist DHβE, can reduce MA-like behavioral effects of nicotine.
Topics: Animals; Central Nervous System Stimulants; Discrimination, Psychological; Dopamine Agents; Drug Partial Agonism; Male; Methamphetamine; Nicotinic Agonists; Receptors, Nicotinic; Saimiri
PubMed: 24389640
DOI: 10.1124/jpet.113.211235 -
Molecular Pharmacology Jul 2009The nicotinic acetylcholine receptors (nAChRs) are targets for human and veterinary medicines as well as insecticides. Subtype-selectivity among the diverse nAChR family... (Review)
Review
The nicotinic acetylcholine receptors (nAChRs) are targets for human and veterinary medicines as well as insecticides. Subtype-selectivity among the diverse nAChR family members is important for medicines targeting particular disorders, and pest-insect selectivity is essential for the development of safer, environmentally acceptable insecticides. Neonicotinoid insecticides selectively targeting insect nAChRs have important applications in crop protection and animal health. Members of this class exhibit strikingly diverse actions on their nAChR targets. Here we review the chemistry and diverse actions of neonicotinoids on insect and mammalian nAChRs. Electrophysiological studies on native nAChRs and on wild-type and mutagenized recombinant nAChRs have shown that basic residues particular to loop D of insect nAChRs are likely to interact electrostatically with the nitro group of neonicotinoids. In 2008, the crystal structures were published showing neonicotinoids docking into the acetylcholine binding site of molluscan acetylcholine binding proteins with homology to the ligand binding domain (LBD) of nAChRs. The crystal structures showed that 1) glutamine in loop D, corresponding to the basic residues of insect nAChRs, hydrogen bonds with the NO(2) group of imidacloprid and 2) neonicotinoid-unique stacking and CH-pi bonds at the LBD. A neonicotinoid-resistant strain obtained by laboratory-screening has been found to result from target site mutations, and possible reasons for this are also suggested by the crystal structures. The prospects of designing neonicotinoids that are safe not only for mammals but also for beneficial insects such as honey bees (Apis mellifera) are discussed in terms of interactions with non-alpha nAChR subunits.
Topics: Amino Acid Sequence; Anabasine; Animals; Carrier Proteins; Drug Design; Humans; Imidazoles; Insecticide Resistance; Ligands; Molecular Sequence Data; Neonicotinoids; Nicotine; Nitro Compounds; Receptors, Nicotinic; Structure-Activity Relationship
PubMed: 19321668
DOI: 10.1124/mol.109.055186 -
Phytochemistry Sep 2020In this study, we determined the pyridine alkaloid content (nicotine, nornicotine, anabasine, anatabine, cotinine, and myosmine) of 58 species and 2 subspecies of the...
In this study, we determined the pyridine alkaloid content (nicotine, nornicotine, anabasine, anatabine, cotinine, and myosmine) of 58 species and 2 subspecies of the Nicotiana genus by ultra-high-performance liquid chromatography coupled with mass spectrometry. We observed clear correlation between Noctiflorae and Suaveolentes sections and their above average accumulation of anabasine in the genus. In addition, the results demonstrated the presence of not only trace amounts but quantifiable levels of myosmine, an alkaloid previously detected in only minute quantities, in the leaves and roots of 16 species. In this study, analysis of gene expression of 58 species and 2 subspecies from the Nicotiana genus by mRNA sequencing was performed for the first time. Sequencing reads were mapped against annotated genes of a Nicotiana tabacum reference genome and expression values were subsequently calculated. Hierarchical clustering of alkaloid biosynthesis pathway genes and alkaloid content composition revealed patterns clearly segregating Nicotiana sections. Correlation of gene expression with alkaloid accumulation phenotypes was evident, including low putrescine methyltransferase expression for all species in the Suaveolentes section or clear correlation of nicotine demethylase with conversion rates of nicotine to nornicotine in the majority of species. Multiple additional correlations between alkaloid accumulation and gene expression values were identified, which makes this study an important fundament toward future scientific exploration of the Nicotiana genus.
Topics: Alkaloids; Anabasine; Plant Leaves; Nicotiana; Transcriptome
PubMed: 32526514
DOI: 10.1016/j.phytochem.2020.112424