“Senna” plants in The Sudan
Prof. Gamal E.B. El Ghazali,
Medicinal And Aromatic Plants & Traditional Medicine Research Institute, National Centre for Research, Khartoum, Sudan.
“Senna” is a name of a diverse number of plants throughout the tropics. The name is of Arabic origin meaning brightness, derived from the distinctive appearance of the bright yellow flowers of these plants. Senna plants are named according to their geographical distribution e.g. Indian senna, Italian senna, Alexandrian senna etc., or according to specific shapes they possess e.g. Sickle-pod senna, ring-worm senna etc., or according to their folkloric uses e.g. coffee senna, purging senna etc. These senna plants are legumes and belong to the flowering plant genus Senna.
The genus Senna occurs naturally in the tropics and subtropics with an estimated number of species in the range of 260 to 350. It is an important genus due to its various economical uses especially for medical purposes.
According to the Swedish botanist Carl Linnaeus, the genus was included in the genus Cassia, but latter, the English botanist Philip Miller (1754) segregated the genus Senna from the genus Cassia.
In Sudan, the genus Senna is represented by 12 species distributed mainly in Northern, Central and western Sudan with an outstanding widespread presence of Senna alexandrina Mill. (Alexandrian or Indian senna), Senna italica Mill. (Italian or Senegal senna) and Senna occidentalis (L.) Link. (Coffee senna).
Both Senna alexandrina and Senna italica have oblong fruits or pods and are named locally as “Senna Maka” or “Senna Senna”, whereas Senna occidentalis has cylindrical fruits or pods and is named “Sorieb”. Senna alexandrina possesses horned flat fruits and leaflets with acute apexes, whereas Senna italica has curved corrugated fruits and leaflets with obtuse apexes.
In The Sudan, both Senna alexandrina and Senna italica are widely used as laxatives, in addition to other folkloric medicinal uses such as giargiasis, as anthelmintic, anti-rheumatic and for wounds. On the other hand, Senna occidentalis is used as a substitute for coffee, against ringworm, as diuretic, for wounds and in the treatments of jaundice.
The laxative properties possessed by various species of the genus Senna are well-known worldwide, for a long time and is included in several herbal pharmacopeias. However, in many countries, the standardized common name “senna” refers to Senna alexandrina.
Hydroxyl Anthrancene Glycosides are considered to be the primary active components of Senna. These compounds consist of Dianthrone Glycosides (including sennosides A, B, C, D), and Anthraquinone Glycosides. The sennosides, particularly sennosides A and B, which are present with varying ratios on the fresh and dried leaves and pods, are thought to be primarily responsible for the laxative effects of senna. These sennosides softening stool by increasing fluid secretion, stimulate bowel movement (Stimulant) and decrease intestinal transit time.
Senna leaves and senna pods are included in volume one of WHO Monograph and are considered as safe and effective stimulant laxative and approved as non-prescriptive medicine for short term relief of constipation.
Senna plants specially those belonging to Senna alexandrina may be considered as one of the promising medicinal plants of The Sudan, in terms of economic importance in local, regional and international markets and thus constitute a very important national resource. Beyond their direct use in traditional medicine, they can be exported as crude or purified extracts or can be used in domestication of herbal drug industry in The Sudan.