Scientific Name(s): Cassia acutifolia Delile, Cassia angustifolia Vahl
Common Name(s): Senna
C. acutifolia is native to Egypt and the Sudan, while C. angustifolia is native to Somalia, the Middle East, and India. Plants known as wild senna (Cassia hebecarpa Fern. and Cassia marilandica L.) grow on moist banks and in wooded areas in the eastern United States. This plant should not be confused with cassia, a common name for cinnamon. Senna is a low-branching shrub that grows to about 1 m tall. It has a straight, woody stem and yellow flowers. The top parts are harvested, dried, and graded. Tinnevelly senna is hand-collected, while Alexandria senna is harvested and graded mechanically. There are more than 400 known species of Cassia.1, 2 A synonym is Cassia senna L.
Senna was first used medicinally by Arabian physicians in the 9th century AD.1 The plant's name is derived from the Arabic word sena and the Hebrew word cassia, which means "peeled back," a reference to its peelable bark. Senna has long been used in traditional Arabian and European medicine, primarily as a cathartic. The leaves were brewed into a tea and administered as a strong laxative.
Because it is often difficult to control the concentration of active ingredients in the tea, its effects may be unpredictable. Standardized commercial dosage forms have been developed and are available as liquids, powders, and nonprescription tablets in over-the-counter laxatives.3, 4
Senna contains anthraquinones, including dianthrone glycosides (1.5% to 3%), sennosides A and B (rhein dianthrones), and sennosides C and D (rhein aloe-emodin heterodianthrones). Numerous minor sennosides have been identified and appear to contribute to senna’s laxative effect. The plant also contains free anthraquinones in small amounts, including rhein, aloe-emodin, chrysophanol, and their glycosides. Senna pods contain the same rhein dianthrone glycosides as the leaves.
Carbohydrates in the plant include 2% polysaccharides and approximately 10% mucilage, consisting of galactose, arabinose, rhamnose, and galacturonic acid. Other carbohydrates include mannose, fructose, glucose, pinitol, and sucrose. Senna’s flavonols include isorhamnetin and kaempferol. Glycosides 6-hydroxymusizin and tinnevellin are also present.
Uses and Pharmacology
Senna has been studied for laxative effects in rats, although the widespread use and acceptance of senna make data from animal studies irrelevant.7
Quality clinical trials evaluating the efficacy and safety of senna in the treatment of constipation, as well as comparative trials comparing senna with other laxatives, are generally lacking.3, 8, 9, 10 However, a 2014 double-blind, randomized, active-comparator trial (N = 56 intent-to-treat; n = 43 protocol) found senna (2 capsules daily for 6 days) to be as effective as lubiprostone (Amitiza) for improving constipation-related symptoms and quality of life in adults who experienced opioid-induced constipation following orthopedic surgery.33
Widespread use of senna and older clinical studies have led to the acceptance of senna as an effective laxative in adult populations for the treatment of chronic constipation, constipation due to other medicines (such as opioids), and in preparing the bowel for diagnostic procedures, although alternative laxatives may be safer and more effective.3, 8, 11
Senna leaves or pods have been used as a stimulant laxative at dosages of 0.6 to 2 g/day, with a daily dose of sennoside B from 20 to 30 mg.3, 4 A bitter tea can be made containing senna 0.5 to 2 g (0.5 to 1 teaspoon). Senna should not be used at high doses or for extended periods of time.
Senna may be standardized according to sennoside content and is available in multiple forms commercially, as well as in combination with other laxatives.3
Senna should not be used at high doses or for extended periods of time,3, 4 and should not be used in children younger than 2 years without consulting a health care provider. In children younger than 12 years and in elderly patients, alternative laxatives may be more effective.3
Pregnancy / Lactation
Category C. The use of senna during pregnancy is controversial. Because of the minimal absorption of senna glycosides by the intestines, a teratogenic effect is not expected. Some data suggest endometrial stimulation, as well as mutagenic and genotoxic effects with senna use.3, 12 In a 2009 case-control epidemiological study, the use of senna was not associated with a higher risk of congenital abnormalities in the offspring of pregnant women with constipation.13
Patients with intestinal obstruction should avoid senna, and it should be used with caution in patients with hemorrhoids or inflammatory bowel conditions.3
Long-term use of any laxative, particularly stimulant laxatives such as senna, may result in laxative dependency, characterized by poor gastric motility in the absence of repeated laxative administration.3
Allergies, including occupational asthma, have been reported.3
Long-term use of senna and its anthraquinone glycosides has been associated with pigmentation of the colon (melanosis coli). Case reports exist of reversible finger clubbing (enlargement of the ends of the fingers and toes) following long-term abuse of senna-containing laxatives.19, 20, 21, 22, 23, 24, 25
Senna abuse has been associated with the development of cachexia and reduced serum globulin levels after long-term ingestion.24
An association between long-term laxative use and colon cancer has been reported. In vitro and animal studies regarding the genotoxicity of senna extracts have produced conflicting data.3, 24, 29, 30, 31, 32
This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.
This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.
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- Drug class: laxatives
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