Senna obtusifolia

Senna obtusifolia, known by common names including Chinese senna, American sicklepod and sicklepod, is a plant in the genus Senna, sometimes separated in the monotypic genus Diallobus. It grows wild in North, Central, and South America, Asia, Africa, and Oceania, and is considered a particularly problematic weed in many places. It has a long-standing history of confusion with Senna tora and that taxon in many sources actually refers to the present species. In the traditional medicine of Eastern Asia, the seeds are called jué míng zǐ in Chinese (simplified: 决明子; traditional: 決明子), gyeolmyeongja in Korean, and ketsumeishi in Japanese. The green leaves of the plant are fermented to produce a high-protein food product called kawal which is eaten by many people in Sudan as a meat substitute. Its leaves, seeds, and root are also used in folk medicine, primarily in Asia. It is believed to possess a laxative effect, as well as to be beneficial for the eyes. As a folk remedy, the seeds are often roasted, then boiled in water to produce sicklepod tea. The plant's seeds are a commercial source of cassia gum, a food additive usually used as a thickener and named for the Chinese Senna's former placement in the genus Cassia. Roasted and ground, the seeds have also been used as a substitute for coffee. In vitro cultures of S. obtusifolia such as hairy roots may be a source of valuable secondary metabolites with medical applications.

Description

An annual or perennial herb. Often it has a bad smell. It can be a shrub 0.6-2.5 m tall. It has slightly hairy stems. The leaf stalk does not have a gland but the axis of the leaf does. The leaf has leaflets in 3 pairs. They are oval and 1-6 cm long by 0.5-3.9 cm wide. The top of the leaf is rounded but with a sharp tip. It is wedge shaped at the base. The flower stalks have one or 2 flowers. The stalk for the flower cluster is very short, but the stalk for the individual flowers is 1-3.5 cm long. The flower petals are orange-yellow and 1-2 cm long. The fruits are thin slightly curved and tapering pods. They are 13-23 cm long and 4-7 mm wide. The seeds are brown. They are 4.5-6.5 cm long by 2-4 mm wide.

Edible Uses

The young leaves are cooked and used as a vegetable, and are fermented into a high-protein supplement. The fermentation juice is made into stew with okra, beef and salt. The seeds are occasionally dried, ground into powder, cooked and eaten, and are also roasted as a coffee substitute.

Traditional Uses

The young leaves are cooked and used as a vegetable. Caution: Older leaves can cause diarrhoea. The leaves are fermented into a high protein supplement to meat. The juice during fermentation is made into a stew with okra, beef and salt. The seeds are occasionally dried and ground into powder and cooked and eaten. Caution: The seeds are possibly poisonous and should be well cooked. Seeds are also roasted and used as a coffee substitute.

Medicinal Uses

The leaves are anthelmintic, laxative and poultice. They are used to rid the body of parasites and as a treatment against vomiting and stomach-ache. Externally, they are used to treat skin infections, sores, ulcers and insect bites. A decoction of the leaves is used to treat eye complaints. The laxative properties of Senna species are attributed to anthraquinones. The roots are used as a laxative and anthelmintic. The seeds are eaten, combined with a leaf decoction, to treat conjunctivitis.

Known Hazards

Older leaves can cause diarrhoea. The seeds are possibly poisonous and should be well cooked.

Distribution

A tropical plant. It grows throughout the tropics. It is mostly a weed of roadsides and waste places. It grows from sea level to 2,000 m altitude. In Papua New Guinea it grows at about 80 m altitude. It grows along rivers and near lakes. In Africa it grows up to 1,700 m altitude. It can grow in arid places.

Where It Grows

Africa, Angola, Argentina, Asia, Australia, Bahamas, Bangladesh, Belgium, Belize, Benin, Bolivia, Botswana, Brazil, Burkina Faso, Burundi, Cameroon, Caribbean, Central Africa, Central African Republic, CAR, Central America, Chad, Colombia, Comoros, Congo DR, Congo R, Costa Rica, Côte d'Ivoire, Dominican Republic, East Africa, Ecuador, El Salvador, Equatorial-Guinea, Ethiopia, Fiji, French Guiana, Gabon, Gambia, Ghana, Guatemala, French Guiana, Guianas, Guinea, Guinée, Guinea-Bissau, Guyana, Haiti, Hawaii, Honduras, India, Indochina, Indonesia, Ivory Coast, Jamaica, Kenya, Laos, Liberia, Libya, Madagascar, Malawi, Malaysia, Mali, Mauritania, Mauritius, Mexico, Middle East, Mozambique, Myanmar, Namibia, Nicaragua, Niger, Nigeria, North Africa, North America, Oman, Pacific, Pakistan, Palestine, Panama, Papua New Guinea, PNG, Paraguay, Peru, Puerto Rico, Reunion, Rwanda, Sao Tome and Principe, Saudi Arabia, SE Asia, Senegal, Sierra Leone, Socotra, Somalia, South Africa, Southern Africa, South America, S Sudan, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Trinidad-Tobago, Uganda, USA, Venezuela, Vietnam, West Africa, West Indies, Yemen, Zambia, Zimbabwe,

Cultivation

It can be grown from seed.

Propagation

Seed - pre-soaking for 12 hours in warm water, or abrading the seed with sand can improve germination rates and reduce germination time.

Other Uses

The seeds, the macerated leaves and the roots provide black, blue, yellow and orange dyes. A yellow phenolic pigment, cassiaxanthone, has been isolated from the roots of Senna species. Myrothecium verrucaria, a fungus isolated from sicklepod, is used for control of nematodes in food crops and ornamental plants and is widely tested as a herbicide against weeds like water hyacinth (Eichhornia crassipes), Chenopodium album and Senna obtusifolia itself. Strains of Fusarium oxysporum and Alternaria cassiae were similarly obtained and showed considerable control of Senna species if applied at the pre-emergence stage. The stems are used to make mats and fences. A natural pioneer within its native range, where it can rapidly colonize open land in the first stage of it returning to forest.

Production

The tender leaves are plucked off the plant.

Other Information

It is not known if they are used in Papua New Guinea. It is cultivated as a vegetable. Young leaves, flowers and seeds are commonly eaten in some places.

Notes

There are 100 Cassia species. This group has been revised to a smaller more consistent group. Also as Caesalpinaceae.

Nutrition

Synonyms

Also Known As

Ajada, Bamdisa, Banikonoka tiga, Brusca cimarrona, Brusca hembra, Charamazca, Cheporon, Coffeeweed, Danfurindo, Djambaduro, Ebisu-gusa, Eedo, Elekmari, Emang, Emany, Gelenggang kechil, Gelenggang nasi, Gelenggang sayor, Godach, Kalahan, Ketepeng, Kilikili, Lapirondyek, Low senna, Luga, Luge, Matapasto, Mpala-ntanga, Muong la-ta, Nachanocu, Ombokodriek, Oyado, Palapantin, Pintcheira-do-mato, Pumaria, Riyer, Sicklepod, Tafasa, Tchunta, Thakara, Ubangue, Ulodje

References (55)

• Abbiw, D.K., 1990, Useful Plants of Ghana. West African uses of wild and cultivated plants. Intermediate Technology Publications and the Royal Botanic Gardens, Kew. p 41 (As Cassia obtusifolia)
• Achigan-Dako, E, et al (Eds), 2009, Catalogue of Traditional Vegetables in Benin. International Foundation for Science.
• Addis, G., Asfaw, Z & Woldu, Z., 2013, Ethnobotany of Wild and Semi-wild Edible Plants of Konso Ethnic Community, South Ethiopia. Ethnobotany Research and Applications. 11:121-141
• Agea, J. G., et al 2011, Wild and Semi-wild Food Plants of Bunyoro-Kitara Kingdom of Uganda: etc. Environmental Research Journal 5(2) 74-86
• Andabati, B., & Muyonga, J., 2014, Phenolic content and antioxidant activity of selected Ugandian traditional medicinal foods. African Journal of Food Science. 8(8), pp 427-434 (As Cassia obtusifolia)

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