Alkaloids Overview and Functions

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary characteristic of alkaloids that is reflected in their name?

They contain a high proportion of carbon.

They are always found in monocot plants.

They are acidic in nature.

They are derived from 'al kaly,' meaning basic or soda. (correct)

Which plant family is NOT known to be rich in alkaloids?

Solanaceae

Labiatae (correct)

Apocynaceae

Papaveracea

Which of the following best describes the principal function of alkaloids in plants?

Facilitating water transport throughout the plant.

Structural component of plant cell walls.

Defense mechanism against herbivores. (correct)

Primary energy storage.

Which type of amine is LEAST commonly found within alkaloid structures?

Primary amines (C) Signup and view all the answers

An alkaloid is classified as having a 'sympathomimetic' effect. What does this imply about its pharmacological activity?

It mimics the effects of the sympathetic nervous system. (B) Signup and view all the answers

Which alkaloid is known for its local anesthetic properties and is sometimes used as a drug of abuse?

Tropane (A) Signup and view all the answers

What is the primary use of pilocarpine, an imidazole alkaloid?

Treatment of glaucoma (B) Signup and view all the answers

Which class of alkaloids is noted for being potentially toxic to humans?

Quinolizidine alkaloids (A) Signup and view all the answers

Which alkaloid, found in tobacco, is used in nicotine patches to assist in quitting smoking?

Nicotine (B) Signup and view all the answers

Which of the following is a modified benzyltetrahydro-isoquinoline alkaloid known for its powerful analgesic and narcotic effects?

Codeine (C) Signup and view all the answers

Which alkaloid is known for its activity against the AIDS virus HIV?

Swainsonine (C) Signup and view all the answers

What is the primary use of papaverine, a benzyltetrahydroisoquinoline alkaloid?

As an expectorant and for male impotence (C) Signup and view all the answers

Which of the following is a common purine alkaloid known for its smooth muscle relaxant properties?

Theophylline (A) Signup and view all the answers

Which alkaloid is associated with inflammatory, rheumatic and gastrointestinal disorders?

Acetyl-lycopsamine (A) Signup and view all the answers

Which of the following is a basic skeleton for indole alkaloids?

Indole (C) Signup and view all the answers

Study Notes

Alkaloids

Alkaloids are natural organic nitrogenous bases
Primarily found in plants, but also in microorganisms and animals
Contain at least one nitrogen atom in a heterocyclic ring
Physiologically active
Nitrogen atoms are typically secondary, tertiary, or quaternary amines (rarely primary amines)
Classified based on the basic nitrogen-containing structures from which they are derived (e.g., piperidine, quinoline, indole)
Dicots tend to contain more alkaloids than monocots
Rich alkaloid families include Apocynaceae, Rubiaceae, Solanaceae, and Papaveraceae
Families lacking alkaloids include Rosaceae and Labiatae

Alkaloid Functions

Defense mechanisms (nitrogen source or waste)
Pharmacological activities
Central Nervous System (CNS) effects: depressants (morphine), stimulants (caffeine)
Autonomic Nervous System (ANS) effects: sympathomimetic (ephedrine), sympatholytic (yohimbine), parasympathomimetic (pilocarpine), anticholinergic (atropine), ganglioplegic (nicotine)
Used in:
- Anesthesia (cocaine)
- Treating fibrilation (quinidine)
- Antitumor agents (vinblastine)
- Antimalarial agents (quinine)
- Antibacterial agents (berberine)
- Antiamebic agents (emetine)
Starting materials for drug synthesis

Alkaloid Classification

Biogenetic classification is based on the pathways: acetate or shikimate
Classification by botanical source
Classification by type of amines (primary, secondary, tertiary)

Basic Alkaloid Skeletons

Diagrams of various alkaloid skeletons (quinoline, quinazoline, isoquinoline, pyrrolidine, purine, indole, imidazole, indolizidine, pyridine, tropane) are shown

Tropane Alkaloids

Include compounds like hyoscyamine, scopolamine, and cocaine
Hyoscyamine and scopolamine have anticholinergic activity and are used for antispasmodic and motion sickness prevention.
Cocaine is a local anesthetic
Tropane alkaloids are often derived from the Erythroxylaceae family
Mostly used as drugs to generate stimulation and euphoria, but can lead to dependence and depression

Piperidine Alkaloids

Lobeline: Relieves asthma and bronchitis
Lobelia inflata (Indian tobacco) is a source.

Pyrrolizidine Alkaloids

Pyrrolizidine alkaloids can cause inflammatory, rheumatic, and gastrointestinal (GI) disorders
Examples are present in the slide

Quinoline Alkaloids

Potentially toxic to humans (e.g., sparteine, cytisine, lupinine)

Indoline Alkaloids

Active against HIV

Pyridine Alkaloids

Nicotine is a respiratory stimulant/depressant
Used in nicotine patches to assist with smoking cessation
Tobacco is a source

Tetrahydroisoquinoline Alkaloids

Anhalamine, anhalonidine and anhalomine are variations
Lophocerine is a component.

Benzyltetrahydroisoquinoline Alkaloids

Papaverine is used as an expectorant and for impotence

Modified Benzyltetrahydroisoquinoline Alkaloids

Morphine, codeine, and thebaine/paramorphine are potent analgesics and narcotics

Indole Alkaloids

Reserpine, deserpidine, vinblastine and vincristine are examples
From plants like Vinca minor

Ergot Alkaloids

Contain compounds like lysergic acid, ergometrine, and ergotamine

Imidazole Alkaloids

Pilocarpine is used for glaucoma treatment

Purine Alkaloids

Caffeine is a CNS stimulant and weak diuretic
Theobromine has diuretic and smooth muscle relaxant properties
Theophylline is a smooth muscle relaxant and diuretic that provides relief from bronchospasm

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating world of alkaloids, natural organic compounds primarily found in plants and known for their physiological effects. This quiz covers their classification, sources, and important functions in defense mechanisms and pharmacology. Test your knowledge of various alkaloid families and their impacts on the Central and Autonomic Nervous Systems.