Senna obtusifolia, popularly known as sicklepod or Chinese senna, is a sprawling, herbaceous perennial plant in the genus Senna, sometimes separated in the monotypic genus Diallobus and Fabaceae / Leguminosae (Pea family). The plant is native to Northern, southern and eastern USA, Mexico, Africa, Central America, the Caribbean and tropical South America. It is also widely naturalized in other parts of the world including south-eastern Asia (i.e. the Philippines, Papua New Guinea, Indonesia, Malaysia and Vietnam) and Oceania (i.e. the Galapagos Islands, Palau and Hawaii). It is considered a particularly serious 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. Some well-known common names of the plants are Chinese senna, coffee weed, habucha, java bean, sicklepod, American Sicklepod, sicklepod senna, arsenic weed, foetid cassia, sickle senna, African foetid cassia, Low senna, Slimming Plant, blunt-leaved senna and foetid senna.
Senna obtusifolia has been treated under a wide range of different scientific names and common names. The Plant List currently itemizes a number of synonyms for this species including Cassia obtusifolia, Cassia tora var. obtusifolia and Diallobus tora. Specific epithet obtusifolia comes from the Latin words obtusus meaning dull or blunt and folium meaning leaf in reference to leaf shape. Common name of sicklepod is in reference to its curved, slender seed pods which are 4-6 inches long. 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. In Asia its leaves, seeds, and root are used in folk medicine. As a traditional cure, the seeds are often roasted, and then boiled in water to produce a tea. Roasted and ground, the seeds have also been used as a substitute for coffee.
|Scientific Name||Senna obtusifolia|
|Native||Northern, southern and eastern USA, Mexico, Asia, Africa, Oceania, Central America, the Caribbean and tropical South America. It is also widely naturalized in other parts of the world including south-eastern Asia (i.e. the Philippines, Papua New Guinea, Indonesia, Malaysia and Vietnam) and Oceania (i.e. the Galapagos Islands, Palau and Hawaii). It is considered a particularly serious weed in many places|
|Common Names||Chinese senna, coffee weed, habucha, java bean, sicklepod, American Sicklepod, sicklepod senna, arsenic weed, foetid cassia, sickle senna, African foetid cassia, Low senna, Slimming Plant, blunt-leaved senna, foetid senna|
|Name in Other Languages||Arabic: Kasia hadat al’awraq (كاسيا حادة الأوراق), Tukhme panwar
Assamese: Bon medelua, medeluwa
Australia: Chinese senna, coffee weed, Java bean, sicklepod senna
Bengali: Chakunda, Panevar
Bolivia: Aya-poroto, mamuri
Brazil: Fedegoso, fedegoso-branco, mata pasto, matapasto liso
Burmese: Tan kywe, Tan kywe: ka le, Mo: kya.lak-hpak
Chinese: Jue ming (決明), Xiao jue ming
Colombia: Bicho, bichomacho, chilinchil
Dominican Republic: Brusca cimarrona, brusca hembra
El Salvador: Comida de murcielago, frijolillo
English: African foetid cassia, American sicklepod, Java-bean, Low senna, Sicklepod, Sicklepod senna, Coffeeweed, Slimming Plant, Chinese senna, arsenic weed, blunt-leaved senna, foetid senna, sickle senna
Finnish: Soijasenna, soijasenna
French: Séné, Pistache marron, Casse fétide, Cassie, cafe zerb pian, pistache marron, Cassier Sauvage, Pois puant
Guatemala: Ejote de invierno, ejotil
Hebrew: Senna keha, סנ, senei keheh, סֶנֶא קֵהֶה
Hindi: Chakunda, Chakwar, Panevar, Puadia, Pumaria, Punwad, chakavad (चकवड़), Chirauta choked, chakwar, Chakavat, Chakod, Chakunda, Chakvad, Chakwand, Charota, Edgaj, Prapunat, Tarkil
Japanese: Ebisu-gusa (エビスグサ)
Kannada: Dundu thangadi, Gandutagase, Sagace, Tagace, Tagarasi, Vanavarike, Gandutogache, Tagache
Korean: Gyeol myeong (결명), gyeolmyeongcha (결명차) Gyeol myeong ja, ho gyeol myeong, Gin gang nam cha
Laotian: Lap mun, Nha lap meun
Malayalam: Sakramardakam, Takara, cakrattakara (ചക്രത്തകര), Chakramardakam
Maori (Cook Islands): Pī ‘aungakino
Marathi: Takala (टाकळा), Takla, Tankli, Tarota, Tarva
Mauritius: Cassepuante, herbe pistache
Nepali: Cakamake, Cakramandi, Carkor, Taper, Tapre
Pacific Islands: Coffeeweed, habucha, peanut weed
Paraguay: Taperva, taperva moroti, taperva sayju
Polish: Stracze egipskie, straczyniec
Portuguese: Mata-pasto, Fedegoso branco
Puerto Rico: Dormidera
Russian: Kassiya ostrolistnaya (кассия туполистная), senna tupolistnaya (сенна туполистная)
Sanskrit: Avudham, Chakramarda, Chakramardaka, Chakramardakah (चक्रमर्दकः), Dadmari, Dadrughna, Edgajah (एडगजः), Kharjjuana, Padmatah, Taga, Tarkil, Uranakhyaka, Uranaksha, Uranakshakah (उरणक्षकः), Vimardaka, Vimardakh (विमर्दकः), prapunnata
Spanish: Bicho, Brusca Cimarrona, Brusca hembra, Charamazca, Matapasto, Ororuz, Taperiva, dormidera, ejotillo, sambran, yerba hedionda, ejote de invierno, bicho, brusca hembra, guanine
Tamil: Ciru takarai, cenavu (சேநாவு), Sirudagarai, Tagarai, Thagarai, Vanamavaram, Vindu
Thai: Chumhet thai
Telugu: Tagirise, Tantemu, Tantiyamu
Vietnamese: Thảo quyết minh, Cay Muong ngu, Muong lac, Muong ngu, Muong dong tien, Muong Hoe, Thao quyet minh
|Plant Growth Habit||Erect, bushy, short-lived, upright to sometimes sprawling, annual, herbaceous to semi-woody plant|
|Growing Climates||Grassland, forest edges, riparian habitats, floodplains, disturbed sites, cropped land, pastures, waterways, roadsides, waste land, open woodland and natural grasslands, drainage channels, fallow land, tropical and subtropical environments|
|Soil||Grow in a range of soil types, including well drained fertile soils, heavy-textured and well aerated or sandy soils. It is also well suited for cleared coastal forest countries|
|Plant Size||About 1.5-2.5 m tall and 1 m wide|
|Root||Robust taproot is about 1 m long, with several descending laterals. Unlike many legumes, the roots of S. obtusifolia and S. tora do not support nodules of nitrogen-fixing bacteria.|
|Stem||Plants produce numerous, branched, sprawling stems that are 1.5-2 m long. These stems are usually velvet-hairy when young, but become mostly hairless with age|
|Leaf||Plants produce numerous, branched, sprawling stems that are 1.5-2 m long. These stems are usually velvet-hairy when young, but become mostly hairless with age|
|Flowering season||March to August|
|Flower||Yellow flowers 10-15 mm across are borne on 7-28 mm long stalks. These flowers usually occur in pairs in the leaf forks and are generally located near the tips of the branches. They have five green sepals that are 5.5-9.5 mm long and five yellow or pale yellow petals that are 8-15 mm long|
|Fruit Shape & Size||slender, sickle-shaped, pod that is 6-18 cm long and 2-6 mm wide that is almost cylindrical in cross-section and sometimes slightly flattened or four-angled and curved downwards|
|Fruit Color||Initially green when young turning to brownish-green as they mature|
|Seed||Seeds are 3-6 mm long, yellowish brown to dark red in color, shiny in appearance, and either diamond-shaped (i.e. rhomboid) or irregular in shape|
|Taste||Sweet, bitter, salty|
|Plant Parts Used||Leaves, seeds, roots, fruits|
Sicklepod is an erect, bushy, short-lived, upright to sometimes sprawling, annual herbaceous to semi-woody plant of the pea/bean family that normally grows about 1.5-2.5 m tall and 1 m wide. The lower stems often sprawl along the ground in open areas. Plants produce numerous, branched, sprawling stems that are 1.5-2 m long. These stems are usually velvet-hairy when young, but become mostly hairless with age. The plant is found growing in grassland, forest edges, riparian habitats, floodplains, disturbed sites, cropped land, pastures, waterways, roadsides, waste land, open woodland and natural grasslands, drainage channels, fallow land, tropical and subtropical environments. The plant grow in a range of soil types, including well drained fertile soils, heavy-textured and well aerated or sandy soils. It is also well suited for cleared coastal forest countries.
Compound leaves 8 to 12 cm long are alternately arranged along the stems and are borne on relatively short stalks that are 15-20 mm long. They have two or three pairs of leaflets that are 17-65 mm long and 10-40 mm wide, with those further from the leaf stalk usually being larger. Leaflets are obovate to oblong-obovate with asymmetrical bases, increasing in size from the base to the apex of the leaf, up to 6 cm long and 4 cm wide. The tips of the leaflets are bluntly oval to round, with a very small point at the tip of the main vein. Their surfaces may be either hairless or sparsely hairy and the entire margins are usually edged with tiny hairs. There is a small elongated structure (i.e. gland) 1-3 mm long located on the main leaf axis between the lowest pair of leaflets (occasionally also between the second pair of leaflets as well). There is an extra-floral nectary close to the lowest pair of leaflets on the upper side of each compound leaf. This nectary resembles a small brown spike. The foliage has a slightly rank odor.
The yellow flowers 10-15 mm across are borne on 7-28 mm long stalks. These flowers usually occur in pairs in the leaf forks and are generally located near the tips of the branches. They have five green sepals that are 5.5-9.5 mm long and five yellow or pale yellow petals that are 8-15 mm long. Each flower also has 10 stamens of which seven are fertile with anthers about 3-5 mm long that have a short narrow projection (i.e. beak) on one end and three are staminodes. Flowering occurs mostly from late summer through to late winter (i.e. from March to August).
The fruit is a slender, sickle-shaped, pod that is 6-18 cm long and 2-6 mm wide that is almost cylindrical in cross-section and sometimes slightly flattened or four-angled and curved downwards. These pods are initially green turning to brownish-green as they mature and are slightly concave between each of the numerous seeds. The seeds are 3-6 mm long, yellowish brown to dark red in color, shiny in appearance, and either diamond-shaped (i.e. rhomboid) or irregular in shape. The areole (marking on the seed coat) is very narrow about 0.3 to 0.5 mm wide.
The plant is utilized locally for a variety of reasons, principally as food and medicine, and it is occasionally cultivated for these purposes. The flowers are decorative and the plant is commonly planted as an ornamental near towns.
Health benefits of Sicklepod
In herbal medicine, sicklepod may be used in a tea, or combined with other herbs for superior effect. It can be prepared by crushing the seeds into a powder, or be used as an extract, seed oil, or as noted, as a tea. Modern research has reported few health benefits after using sicklepod which are listed below
1. Cardiovascular Health
The cholesterol-lowering effect of Sicklepod supports the traditional use to support the heart and even the eyes. In humans, a Korean research evaluated Sicklepod in diabetic patients. Cholesterol levels fell as did LDL and triglycerides.
2. Lowers Cholesterol
Researchers have recognized a protein in sicklepod that particularly targets and lowers cholesterol. The protein has been observed to prevent cholesterol creation similar to statins. The benefit noted by researchers is that this particular protein doesn’t lead to the adverse sides effects that statins often cause in muscle tissue.
3. Mild Laxative Effect
Sicklepod provide some reasonable laxative effects. In one research, it has been shown to provide up to 89% of the effect of the more popular drug based on senna. Researcher noted the milder effect could make Sicklepod a potential laxative option for children and pregnant women who should not use the stronger senna.
4. Supports the Liver
Research of anthraquinones shared by S. obtusifolia showed antioxidant activity that improved the liver’s response to ethanol-induced hepatotoxicity.
5. Antioxidant Protection of DNA
The same anthraquinone compounds that supported the liver also showed an ability to protect DNA from damage. Glycosides, another compound in the herb, have also confirmed antioxidant effects.
6. Prevents Infection
Anthraquinones like those in Senna may be known for their laxative effects, but they also supply anti-microbial properties. Studies have confirmed these compounds help prevent bacterial and viral infection.
Traditional uses and benefits of Sicklepod
- Whole plant, especially the root, has purgative and anti-helminthic properties.
- Leaves are used to treat ringworm and other skin diseases.
- In French Guiana root tincture is rubbed on rheumatic areas.
- Leaf infusion is effective for renal calculi.
- It is favorable in the prevention of eye diseases.
- It comforts stomach ache and completely cures it.
- It serves as laxative and promotes the removal of the bowels.
- It softens the stool and cures constipation.
- It overcomes fatigue.
- It provides relief from headache.
- Due to liver tonic effect, it tonifies the Liver and stimulates its functions.
- It has anti-inflammatory properties which efficiently heals the inflammation within the body.
- It is beneficial in purifying and eliminating the impurities from the blood.
- It impacts as cardio tonic within the body to maintain the Heart functions, thus, it reduces the risk of Heart Diseases.
- Fruit is a good remedy for curing arthritis and herpes.
- It promotes strength and calms the nervous system.
- The leaves are used to make a tea-like infusion.
- 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.
- Decoction of the leaves is used to treat eye complaints.
- Seeds are eaten, combined with a leaf decoction, to treat conjunctivitis.
- Decoction of the leaves is used to treat eye complaints in Senegal and Zanzibar.
- Leaves and seeds are used as a remedy for ringworm and scabies.
- Decoction of seeds is used for hepatitis, edema associated with liver problems, hypertension, infantile convulsion, night blindness due to fever, habitual constipation.
- Infusions of the leaves are used for intestinal disorders.
- Poultice of the seeds and leaves are used for scabies, psoriasis, ringworm and eczema.
- Paste of the root is used for ringworm.
- Decoction of leaves is used in children suffering from fever while teething.
- Leaves fried in castor oil are used as application to foul ulcers.
- In Africa and India it is used for the treatment of ulcers.
- Pounded fermented leaves added to food or local gin and taken orally as purgative or anthelmintic.
- Leaves are used to hasten suppuration.
- Malays use decoction of leaves as a mild purgative or as cure for coughs.
- In Ayurveda, seeds and leaves are used for cough, leprosy, ringworm, colic, flatulence, dyspepsia and bronchitis.
- In India, it is used for rheumatism and gout.
- In Indo-china, pods are used for dysentery and Ophthalmia.
- Seeds, ground with sour buttermilk are used to relieve irritation of itchy eruptions.
Ayurvedic Health benefits of Sicklepod
- Colic: Make an infusion of Cassia Obtusifolia leaves. Take it, twice a day.
- Skin Disease: Make a poultice of Cassia Obtusifolia leaves and the seeds. Apply it gently on the affected skin.
- Fever: Prepare a decoction of Cassia Obtusifolia fruit. Keep it for 5 minutes. Take it twice a day.
- Eczema: Make an alcoholic or vinegar maceration of pounded fresh Cassia Obtusifolia leaves. Use it, externally on the affected skin.
- Fermented leaves are used as a meat substitute in Sudan.
- Young, tender leaves are occasionally used as a vegetable throughout Africa and elsewhere.
- Powdered and fermented leaves are used as a condiment.
- Fermented leaves can be made into a high protein food, known as ‘kawal’ in Sudan.
- Pale yellowish juice produced in the fermentation process is skimmed off and make into a stew with okra etc.
- Roasted seeds have been used as a substitute for coffee.
- Leaves are used to make a tea-like infusion.
- In Uganda the seeds are occasionally dried and ground into powder, which is cooked and eaten as a staple food in moderate amounts.
- Seeds have been eaten in times of famine in the Sahel region as well.
- It is used as a mineral and vitamin supplement by certain tribes in Kenya and Senegal.
- Leaves are high in protein (14.4%) and are highly palatable to poultry but excessive consumption can be detrimental.
- Seeds can be used as a mordant in dyeing.
- Seeds, the macerated leaves and the roots provide black, blue, yellow and orange dyes.
- Yellow phenolic pigment, cassiaxanthone, has been isolated from the roots of Senna species.
- Stems are used to make mats and fences.
- Fish poison is made from the crushed leaves in DR Congo.
- Seeds are collected from the wild for the industrial extraction of gums for the food industry in India.
- Roasted seeds are used for tea, coffee or food additives.
- It is also used as a thickener and the seeds are used for commercial cassia gum.
Prevention and Control
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product’s label.
Control of Sicklepod is difficult and can be obtained only with a sustained combination of all available methods. Although repeated discing of summer fallows favors germination and emergence, and tends to reduce seed numbers in the soil, cultivation usually spreads rather than controls these weeds. Hence, single plants should be grubbed out before flowering. Hand pulling is difficult because of the deep, curved taproot, and plants can regrow from underground buds in the crown region. Larger colonies can be slashed but this does not eliminate Sicklepod. Slashing reduces plant vigor which, with a program of top dressing and restricted grazing, enables re-establishment of native pastures. As shading severely limits Sicklepod growth, late emerging seedlings can be somewhat suppressed by young soybean if the rows are narrow enough for rapid canopy closure.
Sicklepod has been a target weed for biological control, mostly in the USA. Alternaria cassiae, formulated as a mycoherbicide, has given >96% control of Sicklepod and increased the yields of soybean. Granular formulations of A. cassiae mycelia with sodium alginate + kaolin, applied pre-emergence, gave 50% control of Sicklepod in soybeans within 14 days and considerably increased crop yield. In greenhouse trials, an inoculum concentration of 10,000 spores/ml of A. cassiae gave 100% control of Sicklepod. Pseudocercospora nigricans has also been identified as a potential biological control agent. Walker and Tilley recognized Myrothecium verrucaria as a potential mycoherbicide agent although it does affect a number of plant species including some economically important crops.
Herbicides that give control of Sicklepod, either alone or in mixtures with other products include: 2,4-D amine (rice); 2,4-DB (groundnuts, soybean); acifluorfen; atrazine; butylate; chlorimuron; chloroxuron; clopyralid; dicamba; dichlorprop; diuron; EPTC; flumetsulam; fluometuron; fluridone; glufosinate; glyphosate and glyphosate trimesium; imazaquin; linuron; metribuzin; MSMA and vernolate.
Hicks et al. show that a mixture of pyridate and 2, 4-DB acts synergistically on Sicklepod without increased damage to groundnut. It occurs in flushes, seedlings emerge after rainfall events, and few herbicides, including etribuzin, imazaquin, chlorimuron, flumetsulam, and glyphosate, provide adequate control and their efficacy can depend heavily on environmental conditions.