Jatropha curcas (PROTA)
|Geographic coverage Africa|
|Geographic coverage World|
|Cereal / pulse|
|Spice / condiment|
|Dye / tannin|
|Forage / feed|
- Protologue: Sp. pl. 2: 1006 (1753).
- Family: Euphorbiaceae
- Chromosome number: 2n = 22, 33, 44
- Jatropha afrocurcas Pax (1909).
- Jatropha, physic nut, purging nut, Barbados nut (En).
- Pourghère, purghère, grand pignon d’Inde, fève d’enfer, gros ricin, médicinier purgatif (Fr).
- Purgueira, pinhao, rícino major, grão de maluco, galamaluco (Po).
- Mbono (Sw).
Origin and geographic distribution
Jatropha curcas probably originated in Mexico or neighbouring parts of Central America, which are the only areas where it has often been collected from undisturbed vegetations. Portuguese seafarers took it to Cape Verde, where it became an export crop, at one time representing 60% of the total value of agricultural exports. It was distributed all over the world long ago and is now naturalized throughout the tropics and subtropics.
Throughout tropical Africa, different parts of Jatropha curcas are used for a range of medicinal purposes. It is a source of oil that is traditionally used for soap production and as a source of energy; it is also an important hedge plant. The oil-rich seeds and seed oil (called ‘oleum ricini majoris’ or for good reason ‘oleum infernale’ or ‘hell oil’) are used as purgative and to expel internal parasites, although their application often leads to strong irritation of the gastro-intestinal tract or even poisoning. The leaves and bark have the same purgative effect. The oil is also applied internally and externally as an abortifacient, and externally as a rubefacient to treat rheumatic conditions and a variety of skin infections, although its use on the skin may also cause an irritative rash. The oil is used as an ingredient of hair conditioners. The latex has a widespread reputation for healing wounds, as a haemostatic and for curing skin problems; it is applied externally to treat infected wounds, ulcers, ringworm, eczema, dermatomycosis, scabies and sarcoptic mange in sheep and goats. Upon drying, the initially viscous latex forms an airtight film, resembling that produced by collodion. The latex has a styptic effect and is used against pains and stings of bees and wasps. Dried and pulverized root bark is made into poultices and is taken internally to expel worms and to treat jaundice. Leaves are also applied on wounds and in decoction they are used against malaria in Mali and Madagascar, while in Benin and Réunion a decoction is taken against hypertension. The leaf sap is used externally to treat haemorrhoids in Benin and Madagascar. In Guinea Bissau a hot water extract of the leaves is taken orally to accelerate secretion of milk in women after childbirth. Fresh stems are used as chew sticks to strengthen the gums, and to cure bleeding, spongy gums or gum boils. A decoction of the roots is a cure for diarrhoea and gonorrhoea. In Madagascar a decoction of the leaves and roots is taken to treat malaria. Jatropha curcas is also used in the preparation of arrow poison and in the Philippines the bark is used to prepare a fish poison. The seeds are often a source of accidental poisoning, both in animals and humans.
The seed oil is not edible as it contains toxic compounds. Traditionally, it is used for the manufacture of candles and soap, as lamp oil and as fuel for cooking. It is a poor lubricant as it dries quickly. Throughout the tropics and warm subtropics Jatropha curcas is increasingly planted for bio-fuel purposes. The oil is either used directly in adapted engines powering local grain mills, oil presses, water pumps and small generators, or first refined by trans-esterification with methanol or ethanol to produce regular fuel suitable for high-performance diesel engines.
The seed cake left after oil extraction is too toxic to be used as animal feed, but constitutes a valuable organic fertilizer rich in nitrogen. Some accessions of Jatropha curcas found e.g. in Mexico are almost free of toxins and the seed cake from such selections would provide a nutritious feedstock on account of the high protein content. Their seeds are sometimes boiled or roasted and eaten as a snack, and young leaves as a vegetable.
Leaf sap yields a black dye or ink that is said to be indelible; the bark yields a dark blue dye, which, however, is not fast. Ash from the roots and branches is used as cooking salt, and as lye in dyeing. Jatropha curcas is widely cultivated in the tropics as a living fence, for erosion control, demarcation of boundaries and for protection of homesteads, gardens and fields against browsing animals. In Madagascar and elsewhere in Africa it serves as a support for vanilla, black pepper and yams. The wood is very poor as fuelwood. Hybrids of Jatropha curcas and other Jatropha species are grown as ornamentals.
Production and international trade
Official statistics on areas planted and production are still lacking. In recent years, Jatropha curcas has become the focus of large planting programmes in several tropical countries on account of its potential as a bio-fuel crop with low agro-ecological demands. Most of these are still in the pilot stage of development, together probably not exceeding 100,000 ha. India alone may have more than 10 million ha of small-scale and large plantations by 2030, mostly on reclaimed wastelands. Countries in tropical Africa with major development projects for jatropha bio-fuel production include Mali, Burkina Faso, Ghana, Tanzania, Malawi, Zambia and Madagascar. The total length of jatropha hedges in tropical Africa is estimated at 75,000 km, yielding potentially 60,000 t of seeds per year.
Prices of jatropha seeds vary between countries. Where seeds were used for manufacturing soap (Mali, Tanzania) the price per kg was close to US$ 0.10. Once the demand for seeds for bio-fuel increases, the prices of seeds will rise. In India a price of US$ 0.40 per l of jatropha-based fuel is expected to be realistic (cost price plus modest profit margin). To this price tax has to be added and the value of carbon- credit-certificates deducted. Prices for gasoil in landlocked countries of West Africa were US$ 0.80–0.97 in 2007. It is estimated that large-scale plantations and oil extraction mills could produce jatropha bio-fuel in West Africa at a price 5–12% cheaper than current gasoil prices. In remote areas, small-scale production and use of bio-fuel from Jatropha curcas is obviously more promising than the modest margins predict.
Decorticated seeds (kernels) contain per 100 g: water 3–6 g, energy 3100–3300 kJ (740–790 kcal), protein 23–29 g, fat 53–70 g, neutral detergent fibre 4 g, acid detergent fibre 0.1–0.2 g, ash 3.8 g. Fat content of whole seeds is 32–45%, since the seed coat constitutes 35–40% of total seed weight. The fatty acid composition of the oil is: palmitic acid 3.5–15.6%, palmitoleic acid 0.7–0.9%, stearic acid 6.7–7.5%, oleic acid 34.3–46.3%, linoleic acid 30.8–43.1%, linolenic acid 0.2% and traces of myristic, pentadecanoic, margaric, margaroleic, arachidic, gadoleic, behenic, lignoceric and nurvonic acids. Depending on the origin, either the oleic or linoleic acid content is higher. The bio-fuel produced after trans-esterification of the oil has characteristics similar to petro-diesel. The energy balance (the total energy inputs into the crop : the energy output) of jatropha bio-fuel is estimated at 1 : 4–5, which is considerably better than for rapeseed (Canola) oil. Protein content of the seed cake after oil extraction is about 60% with a composition in essential amino acids similar to soya bean protein, but higher in sulphur-containing amino acids.
The toxic compounds in the seed and seed-oil are esters of the diterpenoid 12-deoxy-16-hydroxy-phorbol; in toxic cultivars up to 2.7 mg/g has been found, in non-toxic ones 0.1 mg/g. As they are thermo-stable, the oil and seed cake cannot be detoxified by heating. Quantitative toxicity assessment studies have been effected in many animal models. The irritant properties of the seed oil have been evaluated in the mouse irritation test. Another study showed that the oil does not have mutagenic properties, so that there is no danger for workers handling the cake; however, after initiation with 7,12-dimethylbenz(a)anthracene, the oil induced skin tumours. The seeds also contain a toxic protein fraction: ‘curcin’. Purified proteins from this fraction have been shown to inhibit protein synthesis in vitro in a way similar to that of ricin from castor (Ricinus communis L.). However, curcin lacks the protein-moiety that allows ricin to pass cell membranes, making curcin a much less dangerous toxin. Curcin has a significant antitumour effect in several tumour cell lines and its mechanisms are related to the N-glycosidase activity. The anti-metastatic potential of curcusone B, a diterpene isolated from the aerial parts, was investigated against 4 human cancer cell lines. Treatment with non-cytotoxic doses of curcusone B effectively suppresses the metastatic processes. Extracts from the seeds showed pregnancy-terminating effects in rodents, but it is unclear whether this is due to a specific action or a result of general toxicity.
The latex from Jatropha curcas has shown proteolytic activity that may be responsible for some of its therapeutic effects, e.g. healing wounds and haemostatic (coagulating effect). The diluted latex however shows anticoagulant activities. Analysis of the latex resulted in the isolation of the protease ‘curcain’. The wound-healing properties of curcain were investigated in a mouse model. Application of curcain in a hydrophilic ointment (0.5–1%) showed better wound-healing properties than observed for nitrofurazone, a common drug for wound healing. The latex also contains the cyclic octapeptide ‘curcacycline A’ and the cyclic nonapeptide ‘curcacycline B’. Curcacycline A showed a moderate dose-dependent inhibition of human T cell proliferation, while no direct cytotoxic effects were observed. In a clinical trial common warts treated with the latex disappeared completely after 16–20 days. Curcacycline B enhances the rotamase activity of human cyclophilin B. The leaves of Jatropha curcas have a potent cardiovascular action, somewhat similar to that of β-blockers. A methanol extract of the leaves showed moderate protection of human cell-lines in vitro against HIV, while a water extract from the branches strongly inhibited the HIV-induced cytopathic effects with low cytotoxicity. The methanol extract of the roots showed significant activity against castor oil- and magnesium sulfate-induced diarrhoea in mice through inhibition of prostaglandin biosynthesis and reduction of osmotic pressure. The latex shows significant antibacterial action against a variety of gram-positive bacteria. Ground seeds showed molluscicidal activity against different species that are host for human diseases. The seed oil has pesticidal properties comparable to that of neem (Azadirachta indica A.Juss.) against insects such as the cotton bollworm (Helicoverpa armigera) and the cowpea weevil (Callosobruchus maculatus). It is also effective against termites. The latex is strongly inhibitory to several fungal diseases of crops, e.g. Phytophthora palmivora and Fusarium solani and also to watermelon mosaic virus. Steroids (stigmasterol, β-sitosterol, β-sitosterol-β-D-glucoside) and flavonoids have been found to be present too.
Deciduous, somewhat succulent, monoecious shrub or small tree up to 5(–8) m tall; stem arising from a thick, perennial rootstock, with watery to whitish latex; bark smooth, grey or reddish, shiny, peeling off in papery scales. Leaves alternate, simple; stipules minute, soon falling; petiole (3–)10–15(–20) cm long, glabrous; blade broadly ovate in outline, usually shallowly 5-lobed, 7–14(–18) cm × 5.5–14(–18) cm, base shallowly to deeply cordate, apex acute, margins usually entire, glabrous, 5–7-veined from the base. Inflorescence a terminal or axillary umbel-like cyme, often paired, with a solitary female flower terminating each major axis and many male flowers on lateral branches; peduncle up to 5(–7) cm long, hairy; bracts elliptical-lanceolate, c. 1 cm long, acuminate. Flowers unisexual, regular, 5-merous, greenish yellow; male flower with ovate calyx lobes c. 2 mm long, petals fused in lower half, lobes oblong to ovate, c. 3 mm long, disk composed of 5 free glands, stamens 8, in 2 distinct whorls, the 5 outer fused at base, the 3 inner with filaments completely fused; female flower with ovate-lanceolate calyx lobes 4–5 mm long, hairy, petals c. 6 mm long, free, disk composed of 5 free glands, ovary superior, ovoid-ellipsoid, 3-celled, styles 3, fused at base, stigmas 2-lobed, staminodes 10. Fruit a broadly ellipsoid capsule 2.5–3 cm × c. 2 cm, smooth-skinned, initially fleshy and green, turning yellow and eventually dry and black, late dehiscent, 3-seeded. Seeds ellipsoid, 1–2 cm long, mottled black and coarsely pitted. Seedling with epigeal germination, forming a taproot and 4 peripheral roots; hypocotyl elongated; cotyledons broadly oblong and emergent; first 2 leaves alternate.
Other botanical information
Jatropha belongs to the tribe Jatropheae of the subfamily Crotonoideae. The genus comprises about 170 species, most of them in warm temperate and subtropical regions and seasonally dry tropics. Africa counts about 70 native species, Madagascar 1 endemic. Jatropha curcas belongs to subgenus Curcas. Several Jatropha species are widely grown in the tropics as medicinal or ornamental plants; they sometimes escape from cultivation.
The seeds of Jatropha mahafalensis Jum. & H.Perrier, endemic to Madagascar, contain an oil called ‘huile de Betrata’ with similar properties as Jatropha curcas and with similar traditional uses. The oil is also used for lighting and applied as hair oil against lice. A root decoction is taken as an invigorating drink. The latex contains a cyclic heptapeptide, named mahafacyclin A.
Growth and development
Growth in Jatropha curcas is intermittent and sympodial; it follows the architectural model of Leeuwenberg. Dormancy is induced by fluctuations in rainfall, temperature and light. Not all plants respond simultaneously; in a hedge plants without leaves may be found besides ones full of green leaves. Flowers of Jatropha curcas produce nectar and are scented. The nectaries are hidden in the corolla and only accessible to insects with a long proboscis or tongue. The sweet, heavy perfume at night and greenish yellow colour of the flowers suggest that they are pollinated by moths. In inflorescences, the female flowers open one or two days before the male ones or at the same time as the earliest male flowers. Male flowers last only one day. Seed never sets in indoor cultivation unless the flowers are pollinated by hand. Plants raised from seed are more resistant to drought than those raised from cuttings, because they develop a taproot. Fruit development from flowering to seed maturity takes 80–100 days. Plants from cuttings produce seeds earlier than plants grown from seed. Full production is achieved in the 4th or 5th year. Mycorrhizae have been observed on the roots; they promote growth, especially where phosphate is limiting. The potential lifespan of Jatropha curcas is 30–50 years.
Jatropha curcas occurs in semi-arid tropical and warm subtropical climates with mean daily temperatures of 20–30°C and annual rainfall of 300–600 mm. It does not withstand frost, but is resistant to periods of drought of up to 7 months. It will grow on degraded, sandy or gravelly and even saline soils with low nutrient content, but cannot survive in waterlogged terrain. However, economically sustainable oil production requires well-drained soils of reasonable physical and chemical quality, and at least 750 mm annual rainfall, or supplementary irrigation.
Propagation and planting
Propagation is done by seeds or cuttings. The 1000-seed weight is 400–730 g. Seed storage behaviour is orthodox. The average germinating capacity after 7 years storage at 16°C is about 50%. Seeds are sown at the beginning of the rainy season. Soaking overnight improves germination. Under good conditions seeds germinate in about 10 days. Seeds can also be sown in seedbeds or containers and 4–6 months later transplanted into the field. Nursery-grown seedlings have a higher survival rate than direct-seeded ones. Hedges around homesteads or fields are mostly grown from cuttings. Branch cuttings of 30 cm length planted directly in the field a few weeks before the beginning of the rainy season will root and regrow easily, as a wax coat protects the cuttings from drying out. However, raising plants in a nursery from rooted cuttings with only 2–3 nodes, prior to field planting, has the advantage of a much larger multiplication rate for valuable selections intended for high-yielding plantations. Clonal propagation by tissue culture, starting from hypocotyl-, petiole- or leaf-explants, is technically possible but rather expensive for mass-propagation.
In plantations established for oil production, spacings applied are 2–3 m between and 2–2.5 m within rows, giving plant densities of 1350–2500 plants/ha.
Cultural practices in new plantations include regular weeding, pruning and fertilization. Recently planted seedlings have to be protected against ruminants, because they have not yet developed the repellent toxins in leaves and shoots. Pruning starts 3–4 months after field planting to induce a frame with up to 25 branches for increased flowering and fruit set; maintenance pruning of mature shrubs aims at inducing growth of new laterals and restricting height to facilitate harvesting. When grown as a protective hedge, regular pruning is needed to reduce shade on neighbouring crops. Nutrient requirements for maximum oil production are not yet well-defined for Jatropha curcas, but it appears to respond particularly well to organic fertilizers, including the composted fruit walls and seed cake. Leaf litter and prunings from the plantation will also contribute to improving the organic matter content of the soil. Addition of N, P and K fertilizers to the planting hole will boost early establishment and rapid growth of new plantations. Where climatic and soil conditions are favourable and the plants are spaced more widely, intercropping with vegetables or pulses is possible. Fertilization of the intercrop will then also benefit the jatropha crop.
Diseases and pests
Jatropha curcas is rarely attacked by diseases or pests. Powdery mildew may damage leaves and flowers, while Alternaria may cause leaf fall. Caterpillars of Spodoptera litura feed on the leaves, while several species of beetles feed on the leaves of young plants. These pests may also affect intercrops grown together with Jatropha curcas. It is an alternative host for cassava viruses, so it should not be planted as a fence around cassava fields.
Harvesting and separation of seeds from the fruits is done manually. The best pickers can harvest about 30 kg fruit per hour, which is approximately 18 kg of seeds. Since the fruits stay on the branches for quite some time, they have to be picked or knocked down with a stick.
Annual seed production of mature plants, raised from seedlings, may vary from 300 g to 3(–6) kg, depending on the growing conditions and inherent production capacity. Available data from pilot plantations show the following seed yields per ha: 0.5 t within 1 year after field planting, 1.2–1.5 t in year 2 and further increasing to 2.5–3.0 t from year 5 onwards when the plantation is in full production. Yields of 5 t of seeds/ha, which is equivalent to 1.6–2.0 t of oil plus 3.0–3.4 t of seed cake, have been claimed for jatropha plantations under optimum agro-ecological conditions (e.g. India and Nicaragua).
Old and dense hedges in and around villages or towns may produce 2 kg of seeds per m and per year (height 5–6 m, good soil, 800 mm annual rainfall), pruned hedges around gardens and fields usually not more than 0.8 kg.
Handling after harvest
Seeds for planting should be carefully dried in the shade until 6–9% moisture content and stored cool in airtight containers. Traditional oil extraction involves boiling of roasted and ground seeds until the floating oil can be skimmed off the surface. More efficient methods are based on oil extrusion by hand-operated or mechanized screw presses. The extraction efficiency of this cold method of oil extraction is increased considerably by prior crushing of the seeds in a hammer mill. The remaining seed cake requires composting before use as organic fertilizer. The oil may be refined in a continuous trans-esterification reactor to produce bio-fuel of diesel-oil quality and glycerol as a valuable by-product. The bio-fuel represents about 92% in weight of the initial oil.
Several types of Jatropha curcas are known. A non-toxic type is grown in Mexico (no phorbol esters in the seeds). In Nicaragua a type exists with larger leaves with rounded lobes, and larger but fewer fruits and seeds. Male sterile types exist, which produce more fruits than normal types. A provenance trial in the late 1980s showed that different selections from Africa showed significant differences in vegetative development, but not in morphological characters. Wageningen University (Netherlands) has started a programme to collect and evaluate germplasm of Jatropha curcas, maintain it in field gene banks and initiate breeding work.
The Banco Nacional de Germoplasma Vegetal, Departamento de Fitotecnia, Universidad Autónoma de Chapingo, Chapingo, Mexico and the Departamento de Biología, Universidad Nacional Autónoma de Nicaragua, León, Nicaragua both hold about 100 accessions of Jatropha curcas, but collection, characterization and maintenance of germplasm covering the full variation of the species is still very much needed.
Most plant material used so far is derived from simple selection within semi-wild populations or landraces. Between-plant variation for vigour and seed yield is tremendous and great genetic improvement in seed yields and other important characteristics may, therefore, be expected from systematic breeding. Breeding programmes have been initiated recently in several countries, e.g. at Wageningen University (Netherlands), but information on progress is not yet available. Obviously, oil yield per ha will dominate breeding objectives for Jatropha curcas cultivars for bio-fuel production. Cultivars with compact growth would facilitate harvesting.
The multiple traditional uses of Jatropha curcas, as medicinal, nonfood-vegetable oil and auxiliary plant, have been well exploited in the tropics and subtropics for hundreds of years. Its considerable potential as an oil crop for bio-fuel purposes at relatively low costs and modest demands on the local agro-ecosystem has received much attention in recent years. Prospects are that within the next decade or so, Jatropha curcas will become a major source of renewable energy in the drier rural areas of (sub)tropical Asia, Africa and America. Much agronomic and breeding work needs still to be done to maximize the oil production potential per ha and thus improve the economic sustainability of jatropha oil production. Rapid multiplication techniques and facilities have to be developed to make improved planting material available in adequate amounts. This is especially urgent as planting of unimproved material not only leads to low returns on investments, but may also lead to a loss of interest in this crop. More research should also be initiated on medicinal properties of different plant parts, e.g. wound healing, antimalarial and anti-HIV effects. Investigation of the agronomic and medicinal potential of other Jatropha species would be valuable as well.
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Correct citation of this article
Henning, R.K., 2007. Jatropha curcas L. In: van der Vossen, H.A.M. & Mkamilo, G.S. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 11 November 2020.
- See the Prota4U database.