Botanical name

Senna alexandrina Mill.

Family

Fabaceae

Common name

Alexandrian senna, Egyptian Senna, Tinnevelly Senna, True senna

Information about the plant

Originally, two different senna species were used medicinally from the genus Cassia within the subgenus Senna: Cassia senna L. (Syn. Cassia acutifolia Delile - Alexandrian or Khartoum senna) and Cassia angustifolia Vahl. (Tinnevelly senna). The later elevation of the subgenus Senna to genus level also had consequences for these two species. Their generic name is now consistently Senna - the two species are morphologically and microscopically distinguished only marginally by their constituents - and they have been combined as Senna alexandrina Mill. The distribution of Alexandrian senna extends to the warm, dry regions of north-central Africa, including Sudan, Egypt, and eastwards through the Arabian Peninsula to South India.

Alexandrian senna is a shrub 60 cm to 2 m tall with five to nine pairs of pinnate leaves. The leaflets are linear to lanceolate and up to 6 inches long. The original Latin epithets "acutifolius" (= pointed leaves) and "angustifolius" (= small leaved) refer to the shape of these leaflets. The pale-yellow, zygomorphic flowers grow in clusters in the leaf axils. The fruits are pods up to 5cm long.

Medicinally used parts of plants (herbal drug)

The dried leaflets (Sennae foliolum) and dried fruits (Sennae fructus) are used. The commercially available drugs come mainly from Sudan and India.

Constituents of the herbal drug

Senna leaves and fruits contain anthranoids (hydroxyanthracene derivatives, "anthraquinones"), mainly sennosides A to D (dianthrone glucosides).

Quality of the drug

The quality of the following drugs and drug preparations is specified in the European Pharmacopoeia (Ph. Eur.):

• Senna leaves (senna folium)
• Senna fruits (Sennae fructus)
• Standardized dry extract of senna leaflets (Sennae folioli extractum siccum normatum)
• Standardized dry extract of senna fruit prepared with water (Sennae fructus extractum aquosum siccum normatum)
• Standardized dry extract of senna fruit prepared with aqueous-alcoholic mixtures (Sennae fructus extractum hydroalcoholicum siccum normatum)

Medical applications

Recognised medical use

The HMPC has accepted the internal use of senna leaves and senna fruits for the short-term treatment of occasional constipation as a “well-established use”. Another use for senna fruits is for bowel cleansing prior to clinical procedures that require a clean bowel.

ESCOP: Senna leaves and senna fruits for short-term treatment of occasional constipation.

Traditional use

No listing as a traditional herbal medicinal product (Article 16a of Directive 2001/83/EC).

Herbal drug preparations in finished dosage forms

• Cut senna leaves or senna fruits for tea preparation
• Powdered senna leaves or senna fruits in granules, tablets, and coated tablets
• Senna fruit/senna leaf dry extracts standardized to anthranoids (sennoside B) (extraction solvent: water or ethanol 60%) in coated tablets, tablets, and instant teas

Dosage

Finished medicinal products: See patient information leaflet.

Tea: 20 to 30mg of anthranoids per day is sufficient for a laxative effect. This corresponds to a tea infusion prepared from 0.75 to 1.5g of cut senna leaves or senna fruits. The tea should be taken in the evening before bedtime. It is recommended in combination with other herbal drugs such as alder buckthorn (also acts as a laxative) or cumin (for flatulence).

Preparation of a tea

Pour approximately 150ml of hot (not boiling) water over 0.75 to 1.5g of finely chopped senna leaves or senna fruits and strain after 10 to 20 minutes.

Notes

Senna leaves or senna fruits may not be used for longer than 1 to 2 weeks (gut-irritating laxative), long-term use may worsen constipation. It is recommended to take senna leaves or senna fruits only 2 to 3 times per week, in the evening.

Senna leaves or senna fruits should not be used in cases of intestinal obstruction, appendicitis, inflammatory bowel disease (e.g. Crohn's disease, ulcerative colitis), abdominal pain of unknown origin, or severe dehydration. A slight discoloration of the urine may occur during use.

Although there are currently no reports of adverse or harmful effects of senna leaves or senna fruits in pregnant women or the fetus, use during pregnancy is not recommended due to the potential genotoxicity of various anthranoids. Transfer of anthranoids into breast milk cannot be excluded; therefore, use during lactation is not recommended. Children under 12 years of age should not take senna leaves or senna fruits.

Side effects

Rarely, gastrointestinal cramp complaints (reduce dosage!). Prolonged ingestion of senna leaves or senna fruits (laxative abuse) can lead to disturbances in water and electrolyte balance, especially potassium loss. Blood and protein may appear in the urine (hematuria, proteinuria). Chronic use may lead to (reversible) pigmentation of the intestinal mucosa.

Interactions

Chronic use of senna fruits and senna leaves (laxative abuse) can increase the impact of digitalis drugs (drugs with cardiac glycosides) due to potassium deficiency. The effect of antiarrhythmic drugs may also be affected. Concomitant use of thiazide diuretics, adrenal corticosteroids, and licorice root can further increase potassium loss.

References

Herbal drug monographs

HMPC (2020, 2022), ESCOP (2003), WHO (Vol. 1, NIS)

Further literature

Commentary on the European Pharmacopoeia (Senna leaflets, No. 0206; Senna leaf dry extract, 1261; Senna fruit, No. 0207; Adjusted senna leaf dry extract, No. 1261; Adjusted senna fruit dry extract prepared with water, No. 3084; Adjusted senna fruit dry extract prepared with aqueous-alcoholic mixtures, No. 3127)