Pharmacognosy - 5.2 Cardiotonics
Cardiotonics
By Mr. Bhosale, SKCP, Kasbe Digraj
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Introduction
- Cardiotonic agents, also known as cardiac glycosides (though the term isn\'t exclusively limited to glycosides), are a category of drugs with a specific action on the heart.
- These agents work by increasing the force of the heart\'s contractions, which can improve the heart\'s efficiency and help control the heart rate. They are often used in the treatment of various heart conditions, such as heart failure and certain types of irregular heartbeat.
- Cardiotonic agents are typically derived from certain types of plants. One of the most well-known sources is the foxglove plant (Digitalis purpurea), from which the cardiotonic drug digoxin is derived. Other sources include Strophanthus gratus, and Convallaria majalis (Lily of the Valley).
- It\'s important to note that while cardiotonic agents can be highly effective, they must be used with caution due to their potential for toxicity and the narrow margin between therapeutic and toxic doses.
Examples of Cardiotonic Drugs
Digitalis
Synonyms
Digitalis, purple foxglove, finger flower, lady’s glove, Fox-glove Leaves, Folia Digitalis, Nilkanthi(Hindi, Marathi).
Biological Sources
Digitalis consists of dried leaves of Digitalis purpurea. Digitalis purpurea is not indigenous to India
Family
Scrophulariaceae.
Chemical constituents
- Primary Glycosides of Digitalis:
- Digoxin: This is the most well-known and frequently used glycoside derived from Digitalis. It\'s used in the treatment of various heart conditions.
- Digitoxin: This glycoside is similar to digoxin but is less commonly used today due to its longer half-life and higher risk of toxicity.
- Secondary Glycosides of Digitalis: Produced when primary glycosides are metabolized in the body. In the case of Digitalis, these include:
- Digoxigenin: This is the aglycone derivative of digoxin, produced when the sugar molecules are removed from digoxin in the body.
- Digitoxigenin: This is the aglycone (sugar-free) derivative of digitoxin. It\'s produced when the sugar molecules are removed from digitoxin in the body.
- Other constituents include flavonoids, saponins, tannins, and phenolic acids.
Uses
- Historically, Digitalis purpurea has been used as a treatment for dropsy, a condition that involves swelling due to the accumulation of fluid in the body.
- The cardiac glycosides, particularly digoxin, are used in the treatment of heart conditions such as congestive heart failure and atrial fibrillation. They work by increasing the force of the heart\'s contractions and slowing the rate of the heartbeat.
Arjuna
Synonyms
Arjuna tree, Arjun, Terminalia, Arjun bark, Arjuna(Hindi), Sadada, Sadaru(Marathi)
Biological Sources
Arjuna consists of dried stem bark of the plant known as Terminalia arjuna. Tree native to India.
Family
Combretaceae
Chemical constituents
- Major Chemical Constituents:
- Triterpenoid saponins: Arjunic acid, Arjunolic acid
- Flavonoids: Arjunone, Arjunolone, Luteolin
- Minor Chemical Constituents:
- Other constituents include tannins, ellagic acid, gallic acid, oligomeric proanthocyanidins, phytosterols, calcium, magnesium, zinc, and copper.
Uses
- Traditionally in Ayurvedic medicine for centuries, primarily for heart conditions. It is also used for ulcers, asthma, hypertension, and kidney stones.
- The bark of Terminalia arjuna is used in the treatment of cardiovascular ailments, reducing heart failure and reducing the risk of heart attacks. It\'s also used as an antioxidant, anti-inflammatory, and antibacterial agent.