Senna identifies a genus of plants belonging to the Leguminosae family, subfamily Caesalpiniaceae. This genus includes over 250 species of plants, with the most famous being Cassia angustifolia, also known by the synonyms Cassia acutifolia, Cassia senna, and Senna alexandrina. It is an exotic plant native to East Africa, ranging from Sudan to Mozambique. However, it has been cultivated in Asia for a long time, particularly in southern India, where the famous Indian senna or Tinnevelly is produced. It is one of the most widely used laxative plants worldwide.
In this article, we will explore the botanical characteristics of the Senna plant, its properties, common uses, and contraindications.
Description of Senna
Cassia angustifolia is an upright shrub with a simple, initially unbranched stem that usually does not exceed 2 meters in height. Young branches are densely covered in appressed hairs, which means they adhere closely to the surface.
The leaves of Senna are alternately arranged on the branches and are paripinnate. At the base of the petiole, there are two linear or triangular stipules. The leaflets, ranging from 4 to 9 pairs, are elliptical or lanceolate. They have acute apices, often ending in a mucro, which is a sharp point. The base is rounded and asymmetric. The color is greenish-yellow, lighter on the lower side, where there are few hairs lying flat on the surface. The midrib is sunken on the upper side and raised on the lower side.
The flowers of the Senna plant are arranged in long racemes at the ends of the branches. The calyx is divided at the top into 5 lobes. The corolla consists of 5 yellow, oval petals, with the upper one smaller than the others. There are 10 stamens: the upper 3 are very short, the central 4 are of medium length, and the lower 3 are very long.
The fruit of Cassia angustifolia is a dark green or brown, flat, and very thin legume. It thickens only at the seed section, which is also flat and rough.
Useful Parts and Harvesting
In herbalism, the leaflets of the plant are used as a natural laxative, although the pharmaceutical industry, which uses large quantities of it, also uses the pods. The leaves are harvested when they are still relatively tender, as they are quite tough on their own. After harvesting, they are dried in the shade and then packaged.
If you want to try dried or powdered Senna leaves, you can find them here.
Active Principles of Senna
The main constituents of Senna include anthraquinone compounds and free and combined anthranilic compounds such as heterosides, aloin, rhein, catharticin, mucilages, and essential oil.
These active principles give rise to intestinal regulatory, laxative, and purgative properties.
Properties of Senna
As mentioned, Senna is a plant with highly regarded laxative properties used worldwide, although it is intensively cultivated in only a few countries.
The active substances primarily consist of specific anthraquinone glycosides that exert their action in the colon. They reduce the reabsorption of water in the feces while simultaneously stimulating intestinal contractions, facilitating their expulsion. Preparations made from Senna leaves, either as they are or in powdered form, gently affect the intestinal tract when used in appropriate doses, with initial effects seen after about half a day from ingestion (approximately 8-12 hours).
How to Use Senna
Prolonged use or abuse of Senna-based laxatives can lead to tolerance, resulting in constipation. In general, it is always advisable to use herbal laxatives for short periods and consult a doctor immediately if constipation reoccurs after treatment.
Contraindications of Senna Use
Like all laxatives containing anthraquinone derivatives, Senna should never be used in cases of intestinal, hemorrhoidal, and renal inflammation.
Its use is also discouraged in pregnant and breastfeeding women, children, and individuals suffering from abdominal pain of unknown origin. Some studies have reported rare cases of hepatotoxicity. However, more recent studies, considering the recommended quantities for human use, seem to disprove this theory.
Senna, as a laxative and purgative, can be used in various forms. In powder form, at a dosage of 0.5-1 gram on a wafer, to be taken in the evening before bedtime. In an infusion, using 2 grams of dried leaves in 100 ml of water, to be consumed entirely before going to bed. Lastly, in the form of a wine tincture, which is prepared with 20 grams of leaves in 100 ml of white wine, left to macerate for 5 days and taken in 2-3 teaspoons per day.