Senna (genus)

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Senna
Senna sp. inflorescence in Costa Rica
Senna sp. inflorescence in Costa Rica
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Fabales
Family: Fabaceae
Subfamily: Caesalpinioideae
Genus: Senna
Mill.

Selected species
See text

Senna is a large genus of about 250–260 species of flowering plants in the family Fabaceae, subfamily Caesalpinioideae. This diverse genus is native throughout the tropics, with a small number of species reaching into temperate regions.

Typically Senna species have yellow flowers. Some species of Senna are notable for being host to particular butterfly species — for instance Cloudless Sulphur butterflies.

Senna alexandrina is a small shrub, about 0.5-1 m high, with a pale green smooth erect stem, long spreading branches, bearing four or five pairs of leaves. The flowers are small and yellow, the pods broadly oblong and containing about six seeds.

Senna is an Arabian name, and the plant is grown mostly in Nubia. Twice a year the plants are cut down, dried in the sun, stripped and packed in palm-leaf bags and sent on camels to Essouan and Darao then up the Nile to Cairo or else to Red Sea ports.

It is a purgative, similar to aloe and rhubarb in having as active ingredients anthraquinone derivatives and their glucosides. Its action is on the lower bowel, and is especially useful in alleviating constipation. It increases the peristaltic movements of the colon.

Another species of senna, Cassia obovata, is used as a hair treatment with effects similar to henna, but without the red color. The active component is an anthraquinone derivative called chrysophanic acid, which is also found in higher concentrations in rhubarb root. It adds a slight yellow color. Cassia obovata is often called "neutral henna".

Selected species

File:Senna.png

Candle Bush (Senna alata) flowers
S.candolleana

Uses

Medicinal Use

Because of the presence of anthraquinones, senna species are used as the primary ingredient in certain commercial stimulant laxatives. It is also the primary ingredient found in most "dieter's tea." The combination of acting as a stimulant which reduces a dieter's appetite, and the laxative properties that cause food to move through their system before as many calories can be absorbed is a combination that can lead to rapid and even dangerous weight loss.

The stimulant action of Sennosides, the active ingredient in teas and tablets, should be taken into account for those who suffer from any conditions where stimulants are contraindicated, such as past heart disease, high blood pressure, anxiety attacks, etc.

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Culinary use

In some Southeast Asian cuisines (particularly those of Thailand and Laos), the leaves and flowers of Siamese Cassia (Senna siamea, called khi-lek in Thai), either fresh or pickled in brine, are used in cooking, particularly in gaeng khi-lek (khi-lek curry).[1][2]

External links