Calotropis procera (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Dye / tannin
Essential oil / exudate
Medicinal
Timber
Fuel
Forage / feed
Auxiliary plant
Fibre
Climate change

Calotropis procera (Aiton) R.Br.

distribution in Africa (wild)

1, part of flowering branch; 2, flower; 3, fruit. Source: Flore analytique du Bénin

Protologue: Hort. kew. 2, 2: 78 (1811).

Family: Asclepiadaceae (APG: Apocynaceae)

Chromosome number: 2n = 22

• Sodom apple, calotropis, French cotton, small crown flower, rubber bush, swallow wort (En).
• Pomme de Sodome, cotton de France, arbre de soie, bois canon (Fr).
• Algodão-de-seda, bombardeira (Po).
• Mpamba mwitu (Sw).

Calotropis procera is widespread in tropical Africa, including the Indian Ocean islands and the northern parts of South Africa. It is very common throughout the drier parts of West and East Africa, but much less common towards southern Africa. It also occurs naturally from northern Africa east throughout continental Asia to South-East Asia. It is occasionally planted outside its natural distribution area; e.g. in subtropical America and Australia where it was introduced possibly as an ornamental but it has since escaped and naturalized.

In Africa, medicinal uses of Calotropis procera are manifold and are rather similar to those of Calotropis gigantea (L.) W.T.Aiton. Roots, stem bark, latex, leaves and flowers are all used in many and varied ways in traditional medicine. A decoction or infusion of the whole plant is taken as a tonic and purgative in small doses, and as an emetic in larger doses. A decoction or infusion of the stem bark and root bark, or the powdered bark in water is taken to cure diarrhoea, dysentery, intestinal worms, colic, spleen complaints, stomach-ache, cardiovascular problems, pneumonia, fever, jaundice, elephantiasis and leprosy. Dried root powder in water is taken to increase milk flow of nursing mothers and is given to women to ease child birth. Ground roots or the ash of the burnt roots are applied as a salve or rubbed in to treat skin rash, skin infections, venereal diseases and leprosy. Root powder mixed with Capsicum pepper is put in a bath to treat rheumatism and arthritis. The root bark with latex is smoked as remedy for cough. The stem bark is considered in some countries as an aphrodisiac. The latex is also used as an antiseptic, vermifuge, emetic and purgative, and is applied to stings, umbilical cords, and in cases of toothache, caries, ringworm, guinea worm, whitlow, boils, sores, leprosy, syphilis, rheumatism and tumours. Leaf juice is used as a poison antidote, rubbed on scorpion stings and wounds infected by poisoned arrows; leaf pulp is taken to treat snakebites. They are sometimes taken by women to induce abortion and as an uterotonic. Latex is used as nose drops to induce sneezing to reduce headache. A leaf decoction or infusion is drunk to treat colds, whooping cough, oedema, intestinal worms, psychosis and absence of menstruation. A leaf extract is taken as a cardiotonic, and also to treat high blood pressure and palpitations. Fresh leaves ground in milk are taken to treat guinea worm infections and a leaf infusion is taken to treat dysentery. Pounded fresh leaves are put under the pillow to treat insomnia. Leaves are used as mattress stuffing to keep insects away. Dried leaf powder is sprinkled on wounds to improve healing and burnt ground leaves effectively reduce pain and swellings in rheumatic joints. Leaves are heated, grated, mixed with fat and applied as a paste to treat skin diseases and lice. A leaf dressing is applied to the abdomen to ease childbirth and to treat sun stroke. The smoke of dried, burned leaves, and sometimes the stems, is inhaled to calm asthma attacks and severe headache. The flowers are bitter and considered digestive, astringent, anthelmintic, tonic, anti-inflammatory, spasmolytic, stomachic, and useful to treat colds, asthma, catarrh, anorexia, intestinal worms, inflammations and tumours. A decoction of the dried flowers is drunk to treat impotence.

The latex is toxic and can cause rash, blisters and serious inflammations in sensitive persons and it may lead to blindness. Ingesting larger doses of latex produce toxic symptoms like burning in the throat, irritation of the stomach, nausea, vomiting, diarrhoea, tremors, vertigo and convulsions. The latex has been used as a hunting poison and fish poison, and sometimes used for criminal purposes, often in combination with Strophanthus spp. In northern Sudan accidental death of women have been reported, who inserted tampons with the latex to induce abortion. A decoction of the bark or the latex or the ash from the stem is used in veterinary medicine for treating parasitic skin diseases and scabies in cattle, camels and goats. The stem bark is considered to stimulate lactation in cattle.

Sheep, goats and camels eat the leaves, young pods and flowers during droughts, but consumption is low. If the leaves are chopped and mixed with other feed, consumption improves without toxic side effects. The nectar of the flowers is considered toxic, and gives honey a bad taste. Beekeepers therefore often cut the plants nearby hives.

In Benin Peul women make highly prized cheese using the latex as a coagulant. The cheese is fried before being eaten. A macerated stem bark extract is used for removing hairs from hides and also for tanning; it can also be used as a dye. The stem fiber is strong and durable and used to make ropes, bow strings and fishing nets. The seed floss is used for mattress stuffing. In the past both Calotropis procera (French cotton or Akund) and Calotropis gigantea (Madar fibre) were cultivated and used as a source of a strong stem fibre, and their seed floss was used for packing, as it was too short, smooth and light for spinning. The seed floss has been mixed successfully with longer fibres, e.g. cotton, for spinning. Both species have been tested for use in the paper pulp fabrication, and as a source of methane through anaerobic fermentation for biofuel production, although its potential is limited due to its invasive properties. Recently in Iran, commercial interest has grown for the use of the fibers as reinforcement agent for thermoplastics composites. The stems are used as firewood and charcoal in impoverished areas. The coal is also used to polish bull’s horns. The stems produce a smoky fire, suitable for drying fish. The stem pith makes good tinder. The stems are termite proof and used for roofing and building huts. The very light wood can also be used as fishing net floats. Calotropis procera leaves can be used for mulching and green manure. It is planted to prevent soil erosion and is occasionally grown as an ornamental in dry or coastal areas. In Australia Calotropis procera is considered an invasive plant.

In Africa Calotropis procera is only used on a local scale for medicinal purposes. In Nigeria it is sometimes planted as a forage shrub on a small scale. No statistics are available on production or traded volumes or value.

A vast number of publications have been written on the chemical and pharmacological properties of Calotropis procera. All plant parts are toxic, due to the presence of cardiac glycosides (cardenolides). The latex is by far the most rich in cardenolides, with 162 mg/g at dry weight, compared to 2 mg/g of the total leaf dry weight. The latex contains as main cardenolides uscharin (which has been patented to combat uncontrolled cell proliferation), calotropagenin, uscharidin, uzarigenin, calotropin, calotroposide, calactin, calotoxin, voruscharin, ascleposide, coroglaucigenin, proceroside, proceragenin and syriogenin. Some of these compounds might actually be artefacts, formed as a result of hydrolysis during extraction. The quantities of cardenolides in the stem, fruit, leaves and root bark are different from the quantities found in the latex. The main cardenolides of the latex are uscharin and calotropagenin, of the stem uscharidin, calotropin and proceroside, of the leaves calotropin and calotropagenin, of the fruit pericarp coroglaucigenin, uzarigenin and calactin, and of the root bark calotoxin and calactin. The seeds contain 0.23–0.47% cardenolides, mainly coroglaucigenin (sample from Eritrea) or frugoside (sample from Malawi).

Besides the cardenolides, other alkaloids, saponins, sterols, triterpenes, coumarins, tannins and flavonoids were isolated from the whole plant. The major flavonoid is rutin (quercetin-3-rutinoside): roots contained 1.7%, stem 4.8%, leaves 5.0%, flowers 7.6% and latex 9.7%. The whole plant is furthermore rich in resins, fatty acids, proteases, hydrocarbons, amino acids and minerals. The latex contains 11–23% rubber, the triterpenoids α- and β-amyrine, lupeol, taraxasteryl acetate, α- and β-calotropeol, 3-epimoretenol, multiflorenol, cyclosadol, several triterpene esters, the sterols β-sitosterol and stigmasterol, the non-toxic cysteine proteases calotropain, procerain and procerain-B and the alkaloid choline From the root bark several digitanol glycosides were isolated, which lack cardiac activity. From the flowers, cyanidin-3-rhamnoglucose and the triterpene calotropenyl acetate have been isolated. From the leaves a polysaccharide was isolated. The polyphenol content in different plant parts varied from 3.3% (leaf) to 4.9% (stem).

Calotropin is a quick-acting heart stimulant, and is known to be 15–20 times more poisonous than strychnine: minute amounts can cause death. In the cat, the cardiotonic actions of calotroposide, calotoxoside and uscharin are 83%, 76% and 58% of the action of ouabain, respectively. The lethal dose for calotropin is 0.12 mg/kg. Calotropin inhibited spermatogenesis in male rats and rabbits and induced abortion in female rats and rabbits.

Different root bark, stem bark, leaf, flower and latex extracts showed significant anti-ulcer, anti-inflammatory, anticoagulant, analgesic, antidiarrhoeal, spermicidal, antioxidant, hepatoprotective, wound-healing, cough-suppressing, smooth muscle-contracting and neuromuscular blocking activity in various experimental models with rodents; they showed weak antipyretic activity. Different extracts also showed larvicidal, molluscicidal, antimycoplasmal, anthelmintic, antiviral, antibacterial and antifungal activities in vitro and in vivo, as well as dose-dependent inhibitory effects on chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. Different plant extracts displayed highly significant cytotoxic activity against a panel of 57 human cancer cell lines, as well as significant cell division inhibition capacity in cancer cells.

In a feeding trial using the flowers as a substitute of sorghum (Sorghum bicolor L.) hay in a diet for lambs, it was found that the flowers can represent up to 16.5% of the total food ingestion or 33% of the roughage, without significant reduction of weight gain. Shade-dried Calotropis procera leaves contain 94.6% dry matter: 20.9% ash, 19.6% crude protein, 2.2% fat, 43.6% acid detergent fibre, 19.5% neutral detergent fibre, 5% magnesium, 2% oil, 0.59% phosphorus, 0.2% zinc, 0.04% iron and 0.02% calcium.

Calotropis procera has been tried for cultivation in vitro in order to obtain active molecules. Anti-inflammatory and anti-nociceptive proteins were present in callus and root extracts; however, these proteins did not possess cytotoxic or anti-tumorigenic activity. Larvicidal proteins were present, but they were not related to others that have been reported previously in latex.

The diameter of the fiber from the stem bark ranges from 30 to 50 μm and the fiber length ranges from 9.5 to 30 mm.

Alkaloids and cardenolides similar to those of Calotropis procera have been found in Calotropis gigantea and several other Asclepiadaceae.

Lemon juice is sometimes used as a substitute for the latex as a coagulant for making soft white cheese.

Shrub or small tree up to 2.5(–6) m tall, stems erect, simple or branched, woody at base, bark grey or pale brown, fissured, corky, slash yellowish-white, latex copious; young branches densely white hairy, soon almost glabrous. Leaves opposite, decussate, simple and entire, almost sessile; stipules absent; blade oblong-obovate to broadly obovate, 5–30 cm × 2.5–15 cm, apex abruptly and shortly acuminate, base cordate, succulent, densely white short-hairy below when young, pinnately veined with 6–10 pairs of lateral veins. Inflorescence an axillary umbellate cyme up to 10 cm in diameter. Flowers bisexual, regular, 5-merous; pedicel 1–3 cm long; calyx lobes ovate, 4–7 mm × 3–4 mm; corolla pale whitish-green with large lilac to purple patches on the lobes, campanulate, 2–3 cm in diameter, lobes broadly triangular, 11–20 mm × 9–10 mm, united at base for 6–7 mm; corona with 5 compressed lobes, 6.5–11 mm × 3–4.5 mm, adnate to the staminal column, purple; ovary superior, 2-celled, gynostegium c. 6 mm long, stigma head 5-pointed. Fruit a pair of follicles, each follicle ovoid, fleshy, inflated, 6–10 cm × 3–7 cm, many-seeded. Seeds ovoid, flattened, c. 6 mm long, with 3–4 cm long white coma at one end.

Calotropis comprises 3 species and originates in the Old World tropics. Calotropis procera can best be distinguished from Calotropis gigantea by the length of the staminal corona, which is up to 5 mm in Calotropis procera and up to 11 mm in Calotropis gigantea.

Calotropis procera flowers and fruits throughout the year. Growth is rapid during the wet months but slows down during the dry season. Age at first flowering is 2 years. Each flower remains open for 10–12 days; they are mainly pollinated by insects. The seeds are dispersed by wind. Growth can be up to 1 m during the first year after emergence. Senescence of individual stems takes place after about 5 years but plants often resprout afterwards, also after burning or cutting.

Calotropis procera is common in semi-arid conditions on deep, sandy soils, sand dunes, roadsides, rubbish heaps, cultivated and fallow land, disturbed land and waste places, from sea-level up to 1300 m altitude. It is generally regarded as an indicator of overgrazed land and exhausted soil. It grows mostly in dry habitats with mean annual rainfall of 300–400 mm, but also occurs in areas with up to 1000 mm/year. It has even been recorded in excessively drained soils in areas with as much as 2000 mm/year. It favours open habitat with little competition, as competition with tall weeds, bush and grass weakens existing plants, and shade by trees often eliminates it. Calotropis procera is drought-resistant and highly salt-tolerant.

Calotropis procera is propagated by seed, root suckers, root cuttings and stem cuttings. Each year hundreds to thousands of seeds may be produced per plant. There are about 100,000 seeds/kg, half the seed weight being in the coma (seed floss). Seeds do not have dormancy; germination of fresh seed is 55–90% and varies from 1 to 9 weeks. Pretreatment of seeds is not necessary. The seeds can be sown into seedbeds at a depth of 3–4 cm, but sowing directly into pots is also possible because of the high germination rate. An alternating temperature regime of 35–40°C and 20–22°C improves germination. The seeds are not initially responsive to light, but are affected by light quality and become responsive after long exposure to far-red radiation, such as under dense canopy, which inhibits germination.

Mature fruits should be collected just before the dehiscence and the hairs should be removed from the seeds. The seeds should be dried in the sun for 3–4 days before storage. Seeds lose their viability after about one year. Vegetative propagation through stem and root cuttings is very useful in large-scale multiplication of preferred genotypes.

Calotropis procera is well-suited for intensive energy farming in arid or semi-arid regions where frost is not a limiting factor. Cultural practices in plantations include regular weeding, coppicing and fertilization. It has been cultivated in South America and the Caribbean Islands for the production of fibers. A single harvest per season is preferable to a double harvest, as a single harvest saves energy input both on the farm and in the processing plant. Economically sustainable biofuel production plantations require well-drained soils of reasonable physical and chemical quality and at least 500 mm annual rainfall or supplementary irrigation. Where water is not limiting, 10,000 plants/ha at 1 m × 1 m distance is feasible, but usually 5,000 plants/ha at 2 m × 1 m is recommended. During the first year after planting watering is every week, during the second year every two weeks and after the second year every month and no irrigation in rainy season. Nutrient requirements for maximum biofuel production are not yet well-defined, although it reacts very well to organic and inorganic fertilizers. Leaf litter and prunings from the plantation can also contribute to improving the organic matter content of the soil.

In areas where Calotropis procera is not wanted, mechanical and chemical control is difficult, expensive and often impractical. Nevertheless, the quickest way to deal with single plants or small colonies is uprooting or repeated spraying with herbicides. In localized areas some biological control has been reported, e.g. in Sudan, where the fruit fly Dacus longistylus destroyed most of the fruits, and in India where the root parasite Cistanche tubulosa (Schenk) Hook.f. weakened the plants. However, both are not host-specific.

Calotropis procera is rather susceptible to pests. Caterpillars are the main pest but aphids, fruit flies, grasshoppers and other insects also eat or suck the leaves and fruits despite the toxic latex within. The oleander aphid (Aphis nerii) and the caterpillars of the tiger butterfly (Danaus chrysippus) feed on the leaves, using the cardenolides as a chemical defence mechanism. Termites may be a problem locally. Calotropis procera is a host for sandalwood, Santalum album L., a partial root parasite. In India the nematodes Meloidogyne incognita and Meloidogyne javanica are found on the roots, although the leaf extract kills them.

Roots, leaves and bark of young and older plants alike are harvested throughout the year according to need and availability. In some cases, plants are completely uprooted after which the roots are separated from the rest of the plant and both parts are separately processed.

In order to obtain the seed floss, ripe but green and unopened fruits are picked and opened. When the seeds are rubbed lightly against the palm of the hand, they fall off readily from the floss. Stem bark is peeled by hand or mechanically in processing plants to obtain long strips.

Statistics on yield are difficult to obtain as Calotropis procera is often collected from the wild. Reports from India, where it is planted as biofuel suggest that it has a potential crop yield of about 90 t/ha twice a year, although other reports mention 2–40 t/ha of dry material, depending on the agro-climatic conditions of growth. Annual yields of up to 500 kg/ha fibers are reported.

The aerial parts, bark and roots are cleaned, after which they can be used directly or dried in the shade, powdered and stored for future use.

Calotropis procera is widespread in the tropics and subtropics and is certainly not endangered. Selection of superior genotypes is only done on a small scale and no overview is available.

Breeding programs have been initiated recently in e.g. India, but information on progress is not yet available. Most plant material used so far is derived from simple selection within wild populations. Variation between plants for vigour and fruit yield is tremendous and great genetic improvement may therefore be expected from breeding.

Calotropis procera is a very important plant in traditional medicine. Several of the traditional uses have been validated by research, and much pharmacological research has been effected including its anticancer, anti-ulcer, anti-inflammatory, analgesic, anti-diarrhoeal, spermicidal, antioxidant, hepatoprotective, wound-healing, cough-suppressing, smooth muscle-contracting and neuromuscular blocking activity as well as larvicidal, molluscicidal, anthelmintic, antiviral, antibacterial and antifungal activities in vitro and in vivo. However, there is need for more research on the link between activity and particular compounds.

It is probable that Calotropis procera will remain a major medicinal plant and become an even more important multipurpose crop in Africa than it is at present. The industrial demand for Calotropis procera is likely to increase as novel applications are developed. More agronomic and breeding work needs to be done to maximize the biofuel production potential per hectare. Rapid multiplication techniques and facilities have to be developed to make improved planting material available in adequate amounts. The risk of Calotropis procera becoming a weed should be taken into account in areas where it does not occur naturally.

• Ahmed, K.K.M., Rana, A.C. & Dixit, V.K., 2005. Calotropis species (Asclepiadaceae) - a comprehensive review. Pharmacognosy Magazine 1(2): 48–52.
• Arbonnier, M., 2000. Arbres, arbustes et lianes des zones sèches d’Afrique de l’Ouest. CIRAD, MNHN, UICN. 541 pp.
• Baerts, M. & Lehmann, J., 2011. Calotropis procera. [Internet] Prelude Medicinal Plants Database. Metafro-Infosys, Royal Museum for Central Africa, Tervuren, Belgium http://www.metafro.be/prelude. Accessed September 2011.
• Bagherwal, P., 2011. Immunomodulatory activities of the non-dialyzable latex fraction (NDL) from Calotropis procera (Ait.) R. Br. International Journal of Research in Pharmaceutical & Biomedical Sciences 2(1): 114–119.
• Chavda, R., Vadalia, K.R. & Gokani, R., 2010. Hepatoprotective and antioxidant activity of root bark of Calotropis procera R.Br (Asclepediaceae). International Journal of Pharmacology 6(6): 937–943.
• de Freitas, C.D., Lopes, J.L., Beltramini, L.M., de Oliveira, R.S., Oliveira, J.T. & Ramos, M.V., 2011. Osmotin from Calotropis procera latex: new insights into structure and antifungal properties. Biochimica & Biophysica Acta 1808(10): 2501–2507.
• de Oliveira, J.S., Bezerra, D.P., Teixeira de Freitas, C.D., Barreto Marinho Filho, J.D., de Moraes, M.O., Pessoa, C., Costa-Lotufo, L.V. & Ramos, M.V., 2007. In vitro cytotoxicity against different human cancer cell lines of laticifer proteins of Calotropis procera (Ait.) R.Br. Toxicology in Vitro 21(8): 1563–1573.
• Kiew, R., 2001. Calotropis R.Br. In: van Valkenburg, J.L.C.H. & Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. Backhuys Publishers, Leiden, Netherlands. pp. 133–138.
• Manikandan, M. & Arumugam, R., 2010. Potentiality of Calotropis procera on the yield of biocrudes and biogas production. Journal of Phytology 2(4): 33–40.
• Neuwinger, H.D., 1996. African ethnobotany: poisons and drugs. Chapman & Hall, London, United Kingdom. 941 pp.

• Bekele-Tesemma, A., 2007. Useful trees and shrubs for Ethiopia: identification, propagation and management for 17 agroclimatic zones. Technical Manual No 6. RELMA in ICRAF Project, Nairobi, Kenya. 552 pp.
• Bharti, S., Wahane, V.D. & Kumar, V.L., 2010. Protective effect of Calotropis procera latex extracts on experimentally induced gastric ulcers in rat. Journal of Ethnopharmacology 127(2): 440–444.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
• Choedon, T., Mathan, G., Arya, S., Kumar, V.L. & Kumar, V., 2006. Anticancer and cytotoxic properties of the latex of Calotropis procera in a transgenic mouse model of hepatocellular carcinoma. World Journal of Gastroenterology 12(16): 2517–2522.
• de Azevêdo Silva, A.M., da Costa, R.G., Pereira Filho, J.M., Bakke, I.A., da Silva Lôbo, K.M., Lira Filho, G.E. & da Nóbrega, G. H., 2010. Nutritional value of silk flower hay for lambs. Revista Brasileira de Zootecnia 39(1): 2739–2743.
• de Freitas, C.D., de Oliveira, J.S., Miranda, M.R., Macedo, N.M., Sales, M.P. & Villas-Boas, L.A., 2007. Enzymatic activities and protein profile of latex from Calotropis procera. Plant Physiology & Biochemistry 45(10–11): 781–789.
• Hemalatha, R.G. & Padmini, E., 2011. Studies with the latex of the milk weed - Calotropis procera (Ait) R.Br. for spermicidal effect in human. Journal of Pharmacy Research 4(2): 304–307.
• Hong, T.D., Linington, S. & Ellis, R.H., 1998. Compendium of information on seed storage behaviour. Volume 1: A–H. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 400 pp.
• Moustafa, A.M.Y., Ahmed, S.H., Nabil, Z.I., Hussein, A.A. & Omran, M.A., 2010. Extraction and phytochemical investigation of Calotropis procera: effect of plant extracts on the activity of diverse muscles. Pharmaceutical Biology 48(10): 1080–1090.
• Magalhaes, H.I.F., Ferreira, P. M. P., Moura, E.S., Torres, M.R., Alves, A.P.N.N., Pessoa, O.D.L., Costa-Lotufo, L.V., Moraes, M.O. & Pessoa, C., 2010. In vitro and in vivo antiproliferative activity of Calotropis procera stem extracts. Anais da Academia Brasileira de Ciencias 82(2): 407–416.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Nourbakhsh, A., Ashori, A. & Kouhpayehzadeh, M., 2009. Giant milkweed (Calotropis persica) fibers - a potential reinforcement agent for thermoplastics composites. Journal of Reinforced Plastics and Composites 28(17): 2143–2149.
• Orwa, C., Mutua, A., Kindt, R., Jamnadass, R. & Simons, A., 2009. Agroforestree database: a tree reference and selection guide. Version 4.0. [Internet] World Agroforestry Centre (ICRAF), Nairobi, Kenya. http://www.worldagroforestry.org/ resources/databases/ agroforestree. Accessed May 2011.
• Pandey, F.K., Purnima Gopinathan & Tripti Bhatnagar, 2011. In-vitro antimicrobial activity of latex and leaf extract from a common weed Calotropis procera Ait. Environment & Ecology 29(3): 1172–1175.
• Rahman, M.A. & Wilcock, C.C., 1991. A taxonomic revision of Calotropis (Asclepiadaceae). Nordic Journal of Botany 11(3): 301–308.
• Sakthivel, J.C., Mukhopadhyay, S. & Palanisamy, N.K., 2005. Some studies on Mudar fibers. Journal of Industrial Textiles 35(1): 63–75.
• Teixeira, F.M., Ramos, M.V., Soares, A.A., Oliveira, R.S.B., Almeida Filho, L.C.P., Oliveira, J.S., Marinho Filho, J.D.B. & Carvalho, C.P.S., 2011. In vitro tissue culture of the medicinal shrub Calotropis procera to produce pharmacologically active proteins from plant latex. Process Biochemistry 46(5): 1118–1124.
• Tour, N. & Talele, G., 2011. Anti-inflammatory and gastromucosal protective effects of Calotropis procera (Asclepiadaceae) stem bark. Journal of Natural Medicines 65(3–4): 598–605.
• Van Quaquebeke, E., Simon, G., André, A., Dewelle, J., El Yazidi, M., Bruyneel, F., Tuti, J., Nacoulma, O., Guissou, P., Decaestecker, C., Braekman, J.-C., Kiss, R. & Darro F., 2005. Identification of a novel cardenolide (2’’-oxovoruscharin) from Calotropis procera and the hemisynthesis of novel derivatives displaying potent in vitro antitumor activities and high in vivo tolerance: structure-activity relationship analyses. Journal of Medicinal Chemistry 48(3): 849–859.
• Yesmin, M.N., Uddin, S.N., Mubassara, S. & Akond, M.A., 2008. Antioxidant and antibacterial activities of Calotropis procera L. American & Eurasian Journal of Agricultural & Environmental Sciences 4(5): 550–553.

• Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (Editors), 2006. Flore analytique du Bénin. Backhuys Publishers, Leiden, Netherlands. 1034 pp.

• A. Maroyi, Department of Biodiversity, School of Molecular and Life Sciences, University of Limpopo, Private Bag X 1106, Sovenga 0727, South Africa

Maroyi, A., 2012. Calotropis procera (Aiton) W.T.Aiton. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(2): Medicinal plants/Plantes médicinales 2. PROTA, Wageningen, Netherlands. Accessed 3 April 2025.

• See this page on the Prota4U database.