Pharmacognosy - 5.1 Laxatives
Laxatives
By Mr. Bhosale, SKCP, Kasbe Digraj
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Introduction
There is a wide availability of pharmacologic agents for maintaining bowel regularity.
Laxatives are generally classified by their mode of action.
Classification of Laxatives
In general, laxatives can be classified into four main categories:
- Bulk laxatives
- Stimulant laxatives
- Osmotic laxatives
- Stool softeners
1. Bulk laxatives
- Bulk laxatives are a type of laxative that work by increasing the volume of stool, which encourages bowel movement.
- They do this by absorbing water into the intestines, making the stool softer and easier to pass.
- They are typically used to treat constipation and are considered gentler than other types of laxatives.
- Crude drugs that fall into this category are often plant-based and rich in fiber.
- Nevertheless, they do not work until after a few days of consumption and patients need to take plenty of fluids.
- Examples: methylcellulose, wheat bran, ispaghula, psyllium.
2. Stimulant laxatives
- Stimulant laxatives, as the name suggests, stimulate the lining of the intestines and trigger muscle contractions that help move stool through your system.
- They have a more rapid onset of action (about 6 to 12 hours) than bulk laxatives, and are usually given at night to help produce a bowel movement the following morning.
- Examples: Senna, Cascara, Aloe, Rhubarb, Castor oil
3. Osmotic laxatives
- Osmotic laxatives are a type of laxative that work by increasing the amount of water in the gut, which softens the stool and makes it easier to pass.
- They do this by drawing water into the bowel from the nearby tissue, hence the term \"osmotic\".
- They are typically used for short-term relief of occasional constipation, but can also be used for long-term issues under the supervision of a healthcare provider.
- Examples: Magnesium Hydroxide (Milk of Magnesia), Lactulose.
4. Stool softeners
- Stool softeners, also known as emollient laxatives, work by increasing the amount of water the stool absorbs in the gut, making the stool softer and easier to pass.
- They are often used for preventing constipation rather than treating it.
- They\'re particularly useful for people who should avoid straining, such as those recovering from surgery or childbirth.
- Docusate is the most common stool softener. It comes in several forms, including sodium docusate (Colace), calcium docusate, and potassium docusate. Docusate is a surfactant; it allows water and fats to mix, softening the stool.
- Mineral oil is another example.
Examples of Laxative Crude Drugs
ALOE
Synonyms
Aloe Vera, Barbados Aloe, Cape Aloe, Aloe Gel, Gheekvar, Ghritkumari, Korafad.
Biological Source
Aloe is the dried juice collected by incision, from the various species of Aloe vera, such as Aloe perryi, Aloe vera, Aloe barbadensis.
Family
belonging to family: Liliaceae.
Chemical Constituents
- Major Chemical Constituents:
- Aloin: This is a major anthraquinone glycoside present in aloe.
- Barbaloin: This is another major anthraquinone glycoside.
- Aloe-emodin: This is a hydroxyanthraquinone derivative, found in aloe.
- Minor Chemical Constituents:
- Various other anthraquinones and their glycosides, such as emodin, chrysophanic acid, and ethereal oil.
- Polysaccharides, notably acemannan.
- Vitamins, enzymes, minerals, sugars, lignin, saponins, salicylic acids, and amino acids.
Uses
- Aloe gel is used in a variety of dermatological preparations for its skin-soothing and hydrating properties.
- The anthraquinones in aloe, notably aloin and barbaloin, have laxative effects and are used in certain over-the-counter constipation drugs.
- Aloe vera has been used in dental products for its anti-inflammatory and antimicrobial properties, which can help in treating periodontal disease.
CASTOR OIL
Synonyms:
Castor Oil, Palma Christi Oil, Arandi ka tel, Erandela tel
Biological Source
Castor oil is the fixed oil obtained by cold expression from the seeds of Ricinus communis.
Family
Euphorbiaceae
Chemical Constituents
- Major Chemical Constituents:
- Ricinoleic Acid: This is a monounsaturated fatty acid that makes up about 90% of the oil. It\'s responsible for most of the oil\'s biological activity.
- Minor Chemical Constituents:
- Other fatty acids present in smaller amounts include oleic acid, linoleic acid, stearic acid, and palmitic acid.
- The oil also contains minor constituents like sterols, tocopherols, and trace minerals.
Uses
- Castor oil is traditionally used as a laxative for temporary relief of constipation. it\'s used in certain over-the-counter constipation drugs.
- In pharmaceuticals, castor oil is used in the formulation of capsules and tablets due to its excellent properties.
- It\'s used in ointments and creams for its skin-soothing properties.
- Castor oil has been used as an excipient in drug delivery systems due to its ability to enhance absorption.
Ispaghula
Synonyms
Ispaghula, Psyllium, Psyllium Husk, Spogel, Isabgol (Hindi, Marathi)
Biological Source
Ispaghula consists of dried seeds of Plantago ovata.
Family
belonging to family: Plantaginaceae.
Chemical Constituents
- Major Chemical Constituents:
- Mucilage: This is a type of soluble fiber that makes up about 25-30% of the seed by weight. It\'s responsible for most of the seed\'s biological activity.
Uses
- In pharmaceuticals, ispaghula is used in the production of bulk-forming laxatives due to its high mucilage content.
- It\'s also used in certain over-the-counter products for its cholesterol-lowering effects.
- Ispaghula has been used in weight management due to its ability to promote a feeling of fullness.
Senna
Synonyms
Senna, Alexandrian Senna, Tinnevelly Senna, Indian Senna, Sonamukhi (Hindi, Marathi)
Biological Source
Senna is derived from the dried leaflets or pods of Cassia angustifolia, commonly known as Indian Senna.
Other varieties: Cassia acutifolia (Alexandrian Senna)
Family
Leguminosae (Fabaceae)
Chemical Constituents
- Major Chemical Constituents:
- Sennosides: Anthraquinone glycosides Sennoside A, B, C and D. Responsible for the laxative effect of senna.
- Minor Chemical Constituents:
- Also contains rhein, kaempferol, aloe emodin, isorhamnetin. Free chrysophanol, emodin and their glycosides and free aloe-emodin, rhein, their monoanthrones, dianthrones and their glycosides.
Uses
- In pharmaceuticals, senna is used in the production of over-the-counter laxatives due to its sennosides content.
- Exhibit gripping/cramping effect.
- As a stimulant cathartic.
- It\'s also used in certain herbal teas for laxative purposes.