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Related Concept Videos

Cholinergic Antagonists: Pharmacokinetics01:24

Cholinergic Antagonists: Pharmacokinetics

Cholinergic antagonists—such as antimuscarinics—are available in oral, topical, ocular, parenteral, and inhalational formulations. Most antimuscarinics are oral formulations,  while scopolamine is available as a topical patch, and ipratropium and tiotropium are available as inhalation aerosols or powders. Atropine, tropicamide, and cyclopentolate are topically instilled in the eye. Most antimuscarinics are lipid-soluble and readily absorbed from the gastrointestinal tract and the conjunctiva.
Direct-Acting Cholinergic Agonists: Therapeutic Uses01:11

Direct-Acting Cholinergic Agonists: Therapeutic Uses

Direct-acting cholinergic agonists have many therapeutic uses in various medical fields. Choline esters, including acetylcholine, have limited clinical utility due to their non-selectivity and short duration of action. Still, acetylcholine and carbachol are applied topically during ophthalmologic surgery to induce miosis. Pilocarpine, a muscarinic and ganglionic stimulator, effectively treats open-angle glaucoma and alleviates xerostomia and dry mouth caused by radiotherapy or Sjögren syndrome.
Adrenergic Agonists: Mixed-Action Agents01:28

Adrenergic Agonists: Mixed-Action Agents

Mixed-action adrenergic agonists, like ephedrine and pseudoephedrine, directly and indirectly affect adrenergic receptors. These agents stimulate adrenoceptors and indirectly release stored neurotransmitters, amplifying the adrenergic response.
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
Benzene to Phenol via Cumene: Hock Process01:27

Benzene to Phenol via Cumene: Hock Process

The synthesis of phenol from benzene via cumene and cumene hydroperoxide is called the Hock process. First, a Friedel–Crafts alkylation reaction of benzene with propene gives cumene. Then cumene forms cumene hydroperoxide via a radical chain reaction. In the chain initiation step, the benzylic hydrogen is abstracted to give a benzylic radical. In the chain propagation step, the benzylic radical reacts with an oxygen diradical to form a cumene hydroperoxide radical. The cumene hydroperoxide...
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship01:22

Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship

Cholinergic agonists or cholinomimetics mimic the action of acetylcholine to stimulate the parasympathetic nervous system. They are categorized into direct-acting and indirect-acting agents. The direct-acting cholinergic drugs induce the parasympathetic response by directly binding to the muscarinic or nicotine receptors. In comparison, the indirect-acting cholinergic drugs prevent acetylcholine hydrolysis, indirectly contributing to the extended parasympathetic response.
The direct-acting...
Cholinergic Antagonists: Chemistry and Structure-Activity Relationship01:29

Cholinergic Antagonists: Chemistry and Structure-Activity Relationship

Cholinergic antagonists bind to cholinergic receptors and limit the effects of acetylcholine and other cholinergic agonists. Based on the specific cholinergic receptor affinity, these antagonists are classified as muscarinic or nicotinic. Anticholinergics interrupt parasympathetic innervations while sympathetic innervations remain uninterrupted. Muscarinic antagonists are also called 'muscarinic antagonists', 'antimuscarinics', or 'parasympatholytics'. Nicotinic antagonists are called...

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Related Experiment Videos

Lycopsamine and cumambrin B from Eupatorium maculatum.

H Wiedenfeld1, G Hösch, E Roeder

  • 1Pharmazeutisches Institut der Universität, An der Immenburg 4, D-53121 Bonn, Germany. wiedenfeld@uni-bonn.de

Die Pharmazie
|July 22, 2009
PubMed
Summary

Pyrrolizidine alkaloid lycopsamine and guaianolide cumambrin B were identified in Eupatorium maculatum L. Spectroscopic analysis confirmed the structures of these natural compounds.

Related Experiment Videos

Area of Science:

  • Phytochemistry
  • Natural Product Chemistry
  • Organic Chemistry

Background:

  • Eupatorium maculatum L. is a plant species known for its potential bioactive constituents.
  • Pyrrolizidine alkaloids (PAs) and guaianolides are classes of natural products with diverse biological activities.
  • Understanding the chemical composition of medicinal plants is crucial for drug discovery and development.

Purpose of the Study:

  • To isolate and identify specific chemical compounds from Eupatorium maculatum L.
  • To elucidate the structures of the isolated compounds using advanced analytical techniques.

Main Methods:

  • Phytochemical investigation of Eupatorium maculatum L. extracts.
  • Isolation of target compounds using chromatographic techniques.
  • Structure elucidation employing various spectroscopical methods (e.g., NMR, Mass Spectrometry).

Main Results:

  • The pyrrolizidine alkaloid (PA) lycopsamine was successfully isolated.
  • The guaianolide cumambrin B was identified as another major constituent.
  • The structures of both lycopsamine and cumambrin B were definitively determined through spectroscopic data.

Conclusions:

  • Eupatorium maculatum L. contains the pyrrolizidine alkaloid lycopsamine and the guaianolide cumambrin B.
  • The study successfully elucidated the chemical structures of these isolated compounds.
  • This research contributes to the phytochemical knowledge of Eupatorium maculatum L. and provides reference compounds for further biological studies.