Trigonelline inhibits intestinal microbial metabolism of choline and its associated cardiovascular risk.

Gut microbiota based metabolism of choline produces trimethylamine (TMA) which is further converted to a pro-atherosclerotic metabolite, trimethylamine-N-oxide (TMAO) by flavin monooxygenase (FMO3). Trigonelline from the plant Trigonella foenum-graecum has been reported for the treatment of CVD. Aim of the present study was to check the effect of trigonelline on the gut microbiota based conversion of TMA to TMAO. Trigonelline was isolated from hydroalcoholic extract of seeds of Trigonella foenum-graecum. The isolated trigonelline was characterized through TLC and UPLC-MS. Anaerobic microbe responsible for the metabolism of choline to TMA was isolated by culturing the human gut microbiota in choline enriched medium. The isolated bacteria was identified at molecular level based on PCR amplification of 1500bp of 16S rRNA gene sequence. Isolated FMO3 was used for ex vivo conversion of TMA to TMAO. Further, we investigated the effect of trigonelline in isolated gut microbe based metabolism of choline, lipid profile and TMAO levels in mice with or without suppression of gut microbiota with antibiotics. Liquid-liquid purification and chromatographic analysis confirmed the trigonelline purity (87.26%) and which was also confirmed by mass spectroscopy with m/z 137.4 in positive ionization mode. A total of 30 anaerobic microbes responsible for TMA production were isolated and Citrobacter freundii was the superior among others for the production of TMA. In vitro culture of C. freundii in choline enriched medium supplemented with trigonelline resulted in significantly reduction TMA and followed by TMAO production. In ex vivo, a maximum of 85.3% TMAO production was reduced by trigonelline at concentration of about 300 µg/mL. Serum level of lipids and TMAO were significantly altered in choline fed animals with or without suppression of gut microbiota and this phenomenon was reversed upon the oral administration of trigonelline in a dose-dependent manner. This study demonstrates the effect of trigonelline on gut microbiota responsible for choline metabolism and this can be used as a model for evaluation of herbal drugs and its effect in gut microbiota prompted cardiovascular disorders.

Evaluation of Thr6-bradykinin purified from Polybia occidentalis wasp venom in the choline uptake of mammal cortices.

CONTEXT: Thr6-bradykinin is a peptide found in the venom of social and solitary wasps. This kinin, along with other bradykinin-like peptides, is known to cause irreversible paralysis in insects by presynaptic blockade of cholinergic transmission. However, this activity has never been tested in mammals. OBJECTIVE: As such, the objective of this study was to evaluate the effect of Thr6-bradykinin on the cholinergic system of rats. MATERIALS AND METHODS: The peptide was isolated from the venom of the Neotropical social wasp Polybia occidentalis Olivier (Vespidae). After correct identification and quantification by ESI-MS and MS/MS, the peptide was tested in [14C]-choline uptake using rat cortical synaptosomes. Each uptake assay was accompanied by lactic acid dehydrogenase (LDH) activity measurement to evaluate synaptosome integrity in the presence of six increasing concentrations of BK or Thr6-BK (0.039, 0.156, 0.625, 2.500, 10.000 and 40.000 µM). RESULTS: Data revealed that neither BK nor Thr6-BK at any of the six concentrations tested (from 0.039 to 40.000 µM) affected [14C]-choline uptake in synaptosomes. Moreover, there was no increase in LDH in the supernatants, indicating that BK and Thr6-BK did not disrupt the synaptosomes. DISCUSSION AND CONCLUSION: In contrast to previous reports for the insect central nervous system (CNS), Thr6-BK had no effect on mammalian cholinergic transmission. Nevertheless, this selectivity for the insect CNS, combined with its irreversible mode of action may be relevant to the discovery of new sources of insecticides and could contribute to understanding the role of kinins in the mammalian CNS.

Psoralea corylifolia extracts stimulate cholinergic-like psoralen receptors of tadpole-tail melanophores, leading to skin darkening.

The present work was carried out to determine the effects of lyophilized seed extracts of Psoralea corylifolia along with pure psoralen, its active ingredient on the isolated tail-piece melanophores of Bufo melanostictus, a type of disguised smooth muscle cells, which offer excellent in vitro opportunities for studying the effects of pharmacological and pharmaceutical agents. In the present study, it was found that lyophilized extract of P. corylifolia and its active ingredient psoralen induced powerful, dose-dependent, physiologically significant melanin dispersal effects in the isolated tail melanophores of B. melanostictus, which were completely blocked by atropine as well as hyoscine. The per se melanin dispersal effects of lyophilized extracts of P. corylifolia and its active ingredient psoralen were highly potentiated by neostigmine. It appears that the melanin dispersal effects of the extracts of P. corylifolia and psoralen are mediated by cholino-muscarinic or cholino-psoralen like receptors having similar properties that need to be studied further.

Piperine, the main alkaloid of Thai black pepper, protects against neurodegeneration and cognitive impairment in animal model of cognitive deficit like condition of Alzheimer's disease.

Recently, numerous medicinal plants possessing profound central nervous system effects and antioxidant activity have received much attention as food supplement to improve cognitive function against cognitive deficit condition including in Alzheimer's disease condition. Based on this information, the effect of piperine, a main active alkaloid in fruit of Piper nigrum, on memory performance and neurodegeneration in animal model of Alzheimer's disease have been investigated. Adult male Wistar rats (180-220 g) were orally given piperine at various doses ranging from 5, 10 and 20mg/kg BW at a period of 2 weeks before and 1 week after the intracerebroventricular administration of ethylcholine aziridinium ion (AF64A) bilaterally. The results showed that piperine at all dosage range used in this study significantly improved memory impairment and neurodegeneration in hippocampus. The possible underlying mechanisms might be partly associated with the decrease lipid peroxidation and acetylcholinesterase enzyme. Moreover, piperine also demonstrated the neurotrophic effect in hippocampus. However, further researches about the precise underlying mechanism are still required.

Effects of supplemental choline on extracellular acetylcholine in the nucleus accumbens during normal behavior and pharmacological acetylcholine depletion.

Brain microdialysis was used to determine whether systemic or local application of choline would modify the extracellular concentration of acetylcholine (ACh) in the nucleus accumbens (NAc) of freely moving rats. Supplemental choline given intraperitoneally or into the NAc of normal rats did not increase extracellular ACh. When local ACh interneurons in the NAc were treated pharmacologically to deplete the intracellular stores of ACh, then systemic choline (80 mg/kg) was an effective treatment. Specifically, 1) blockade of the high-affinity choline transporter with hemicholinium-3 (HC-3) to reduce ACh synthesis caused a decrease in extracellular ACh, but choline supplementation restored ACh toward its normal level in the NAc. 2) Local bicuculline treatment released ACh to the point of depletion, but systemic choline or locally infused choline helped maintain normal ACh levels. These results suggest that choline supplementation might be useful in preventing depletion of ACh in the nucleus accumbens during pathological conditions.

[Relationship between the choline-blocking and protective actions of m-cholinolytics in chlorophos poisoning]. / Sviaz' mezhdu kholinoblokiruiushchim i zashchitnym deistviem m-kholinolitikov pri otravlenii khlorofosom.

It was established in experiments on mice that the protective effect of metacine and atropine iodomethylate during chlorophos and acetylcholine intoxication is directly proportional to the peripheral m-cholinolytic activity of the drugs. The protective effect of the doses of metacine and atropine iodomethylate equieffective by the choline-blocking effect was equal during acetylcholine intoxication but differed during chlorophos intoxication. Atropine iodomethylate exhibited a stronger selective peripheral m-cholinolytic action than metacine.

Effects of cholinomimetic agents given into the brain of fowls.

1 Effects of cholinomimetic agents, given into the IIIrd ventricle of adult fowls (Gallus domesticus) or infused into the hypothalamus of young chicks, were tested on behaviour, respiratory rate and body temperature.2 Carbachol evoked behavioural and electrocortical arousal but lacked postural and respiratory effects. Contrariwise, pilocarpine increased respiratory rate and induced postural changes, i.e. abduction of the wings, but lacked other behavioural effects and did not alter electrocortical activity. Benzoylcholine induced tachypnoea, postural changes and brief electrocortical arousal. Acetylcholine was ineffective unless given with physostigmine, when electrocortical arousal, postural changes and tachypnoea developed. Methacholine induced tachypnoea and postural changes.3 Effects of carbachol and pilocarpine were prevented by hyoscine and those of benzoylcholine by pempidine; hyoscine and pempidine were required together to prevent the effects of methacholine and to attenuate those of acetylcholine with physostigmine.

A comparison between the blocking actions of 2-(4-phenylpiperidino) cyclohexanol (AH 5183) and its N-methyl quaternary analogue (AH 5954).

1. The neuromuscular blocking activities of AH 5183 (2-(4-phenylpiperidino) cyclohexanol) and its N-methyl quaternary analogue (AH 5954) were compared in rapidly stimulated nerve-skeletal muscle preparations of the rat, chicken and cat.2. The evidence indicated that in isolated preparations the neuromuscular block produced by both AH 5183 and AH 5954 was primarily pre-junctional in origin. That produced by AH 5954 was readily reversible either by washing the tissue or by reducing the stimulation frequency, whereas that produced by AH 5183 was difficult to reverse in these ways.3. Low doses of AH 5954 sensitized the rat hemidiaphragm preparation to the neuromuscular blocking action of choline. The neuromuscular block produced by choline was reversible by tetraethylammonium but not by neostigmine. This suggested that the blocking action of choline is at least partly pre-junctional in nature.4. In anaesthetized cats AH 5954 possessed a biphasic neuromuscular blocking action. The initial phase was rapid in onset, suggestive of a post-junctional action, whereas the second phase was prolonged and reversible by choline, suggestive of a prejunctional inhibitory action on the choline transport mechanism. AH 5183 produced no initial blocking action and was irreversible by choline.5. Both AH 5183 and AH 5954 possessed local anaesthetic and alpha-adrenoceptor blocking actions. These actions and the neuromuscular blocking action were affected to different degrees by quaternization, suggesting that the three main actions of the two drugs are independent.6. It was concluded that AH 5954 and AH 5183 act at different pre-junctional sites at the neuromuscular junction, AH 5954 acting extraneuronally by inhibiting choline transport and AH 5183 intraneuronally at the level of the synaptic vesicle membrane.