Croton tiglium (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Medicinal
Forage / feed

Croton tiglium L.

Protologue: Sp. pl. 2: 1004 (1753).

Family: Euphorbiaceae

Chromosome number: n = 10

Vernacular names

• Purging croton, croton oil plant, croton (En).
• Croton cathartique (Fr).
• Crotone, crotone tiglio (Po).

Origin and geographic distribution

Croton tiglium originates from tropical Asia and China and has been introduced into many parts of the world, including several countries of tropical Africa, e.g. Ghana, Nigeria, Cameroon and Sudan, but an exact distribution in Africa is not known.

Uses

The seed and seed oil have long been used in tropical Asia as a strong purgative, cathartic and poison. In Malaysia one seed is eaten as a purgative by adults and coconut milk is drunk to stop the effect. The lethal dose for an adult is about 4 seeds and for a horse about 15 seeds. The seed oil was formerly included in several pharmacopoeias as a purgative, but because the oil is not stable, it has proved unreliable and has therefore been excluded. The seed oil and bark were widely used in folk medicine as a remedy for cancerous sores and tumours, carbuncles, colds, dysentery, fever, paralysis, scabies, schistosomiasis, snakebite, sore throat and toothache. The oil is a strong vesicant but diluted it can be employed as a counterirritant for various skin affections. Caution should be taken with all applications in view of its toxicity.

In Ghana the seeds are known to be very poisonous, and are used as fish poison or for criminal purposes. In Sudan the powdered seeds mixed with dates are eaten as a purgative. In South-East Asia the root is used as an abortifacient and purgative. The leaves are mentioned as an ingredient of arrow poison and as a poultice to treat snakebites.

An extract of the seed can be used as an insecticide for field application and in stored cereals and pulses. The seed oil may also be used in the production of soap and candles. However, for illumination it can only be used outdoors as the smoke is toxic. Croton tiglium is grown in southern California as an ornamental.

Production and international trade

Roots, seeds and seed oil of Croton tiglium are locally traded in India and South-East Asia. Trade from Asia to Europe started in the 16^th century and continued to be important until the beginning of the 20^th century. Recent trade statistics, however, are lacking. Market value of seeds fluctuates considerably depending on demand.

Properties

All plant parts are toxic, but only the seeds have been chemically analysed in detail. The seed contains 30–45% of a fixed oil named croton oil and about 20% protein. The composition of the oil varies with the method of extraction. The oil comprises the fatty acids oleic acid 37%, linoleic acid 19%, myristic acid 7.5%, arachidic acid 1.5%, palmitic acid 1%, formic acid 1%, acetic acid 0.5%, stearic acid 0.5% and smaller amounts of butyric acid, lauric acid, tiglic acid and valeric acid. The oil also contains a group of proteins called ‘crotin’, about 3.5% croton resin (‘crotonol’), a glucoside called crotonoside (isoguanosine), and a non-volatile unsaturated fatty acid responsible for the purgative properties. Croton oil causes severe inflammation on the skin; it is commonly used in laboratory tests to induce oedema in test animals. The names crotonol and crotin are also used for other chemical compounds.

Crotin is a mixture of the toxic proteins croton globulin and croton albumin. It has haemolytic and blood coagulant properties with a delayed poisonous effect. In humans erythrocytes are merely deformed and rapid antibody formation is induced. The vesicant and irritant properties of the seed oil are mainly due to croton resin, which contains esters of long-chain fatty acids and the diterpene phorbol. Such phorbol esters also show paradoxical biological activity, some being strongly co-carcinogenic, others having anti-cancer activity. 12-O-tetradecanoylphorbol-13-acetate is a standard tumour-promoting agent; several others are well-established causal agents of nasopharyngeal cancer as they can activate Epstein-Barr viruses. On the other hand, phorbol 12-tiglate-13-decanoate exhibits inhibitory activity against P-388 lymphocytic leukaemia in mice; 12-O-acetylphorbol-13-decanoate and 12-O-decanoylphorbol-13–2-methylbutyrate potently inhibit the HIV-1-induced cytopathic effect on MT-4 cells without activating protein kinase C. Crotonoside shows cytotoxic effect against several tumour cell lines in vitro and in vivo in mice as well.

Aqueous extracts of latex and stem bark showed molluscicidal activity against the freshwater snails Lymnaea acuminata and Indoplanorbis exustus; at high doses these extracts were also lethal to the freshwater fish Channa punctatus.

The seed cake retains its toxicity and is thus not suitable for cattle feed.

Description

Monoecious, evergreen shrub or small tree up to 6(–12) m tall; young branches sparsely stellate hairy, soon glabrous. Leaves alternate, almost opposite at the end of shoots, simple; stipules up to 3.5 mm long; petiole up to 2.5(–6.5) cm long; blade ovate to ovate-lanceolate, 5–17 cm × 2.5–9.5 cm, base cuneate to broadly rounded with 2 stalked or sessile glands, apex obtuse to acuminate, margins shallowly toothed to almost entire, glabrous, metallic green to bronze or orange, sparsely hairy beneath. Inflorescence an axillary or terminal raceme 5–7 cm long, with male flowers in upper half and female flowers in lower half. Flowers unisexual, 5-merous; pedicel 2–4 mm long; sepals triangular to ovate, c. 2 mm long, hairy; male flowers with elliptical-lanceolate petals c. 2 mm long, whitish, stamens 15–20, free; female flowers with petals lacking, ovary superior, rounded, c. 2 mm long, densely stellate hairy, 3-celled, styles 3, deeply 2-fid, c. 4 mm long. Fruit an oblong-obovoid to slightly 3-lobed capsule 2–2.5 cm long, dull yellow, roughly stellate hairy, 3-seeded. Seeds ellipsoid-trigonous, c. 9 mm × 6 mm, greyish brown.

Other botanical information

Croton comprises about 1200 species and occurs throughout the warmer regions of the world. It is best represented in the Americas; about 65 species occur in continental Africa and about 125 in Madagascar.

Ecology

Croton tiglium occurs in a wide range of vegetation and soil types, up to 1500 m altitude. In tropical Africa it is usually planted around villages. It tolerates an annual rainfall of 600–1200 mm, an annual temperature of 21–27.5°C and a soil pH of 4.5–7.5.

Management

Croton tiglium is propagated from stem cuttings or seed. There are about 4150 seeds/kg. It may be grown as a pure crop or as an intercrop with cacao or coffee, providing some shade. Plants start flowering after 1.5 years, and seed yield in the 3^rd year may be 200–750 kg seed/ha, and in the 6^th year 750–1000(–2000) kg/ha, when the plant is full-bearing. Seeds ripen in November and December in South-East Asia, and should be collected before the fruits open. Croton tiglium is attacked by several fungi, and also by root-knot nematodes.

Genetic resources

Croton tiglium has a wide distribution from India to Papua New Guinea, and is also cultivated. It is therefore not threatened by genetic erosion. As virtually nothing is known about the distribution of Croton tiglium in tropical Africa, it is not known whether it is genetically diverse there.

Prospects

The seed oil of Croton tiglium is commonly used in laboratories throughout the world for its vesicant properties. The phorbol esters isolated from the oil also have interesting tumour-promoting or tumour-inhibiting properties, and although much research has been done, more is needed to elucidate their future potential. As the other parts of the plant are poisonous as well, it might be worthwhile investigating their chemistry and pharmacology. A large number of pharmaceutical applications of Croton tiglium are being patented in China. The extensive ongoing research may lead to new developments elsewhere too.

Major references

• Burkill, H.M., 1994. The useful plants of West Tropical Africa. 2nd Edition. Volume 2, Families E–I. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 636 pp.

• El Mekkawy, S., Meselhy, M.R., Nakamura, N., Hattori, M., Kawahata, T. & Otake, T., 1999. 12-O-acetylphorbol-13-decanoate potently inhibits cytopathic effects of human immunodeficiency virus type 1 (HIV-1), without activation of protein kinase C. Chemical and Pharmacological Bulletin 47(9): 1346–1347.

• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.

• Philcox, D., 1997. Euphorbiaceae. In: Dassanayake, M.D. & Clayton, W.D. (Editors). A revised handbook of the flora of Ceylon. Volume 11. A.A. Balkema, Rotterdam, Netherlands. pp. 80–283.

• van Welzen, P.C. & Esser, H.-J., 2001. Croton L. 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. 198–203.

Other references

• Abbiw, D.K., 1990. Useful plants of Ghana: West African uses of wild and cultivated plants. Intermediate Technology Publications, London and Royal Botanic Gardens, Kew, Richmond, United Kingdom. 337 pp.

• Duke, J.A., 1983. Croton tiglium L. In: Duke, J.A. (Editor). Handbook of energy crops. [Internet] http://www.hort.purdue.edu/ newcrop/duke_energy/ Croton_tiglium.html. January 2007.

• El Amin, E.M., 1989. Habat-el-Mulluk (Croton spp.): a herbal remedy for internal diseases. Indian Journal of Applied and Pure Biology 4(2): 107–109.

• El Mekkawy, S., Meselhy, M.R., Nakamura, N., Hattori, M., Kawahata, T. & Otake, T., 2000. Anti-HIV-1 phorbol esters from the seeds of Croton tiglium. Phytochemistry 53(4): 457–464.

• Hecker, E. & Schmidt, R., 1974. Phorbolesters - the irritants and carcinogens of Croton tiglium L. Progress in the Chemistry of Organic Natural Products 31: 377–467.

• Kim, J.H., Lee, S.J., Han, Y.B., Moon, J.J. & Kim, J.B., 1994. Isolation of isoguanosine from Croton tiglium and its antitumor activity. Archives of Pharmacal Research 17(2): 115–118.

• Nakamura, N., 2004. Inhibitory effects of some traditional medicines on proliferation of HIV-1 and its protease. Yakugaku Zasshi 124(8): 519–529.

• van Duuren, B.L. & Sivak, A., 1968. Tumor-promoting agents from Croton tiglium L. and their mode of action. Cancer Research 28(11): 2349–2356.

• Yadav, R.P., Singh, D., Singh, S.K. & Singh, A., 2006. Effects of extracts of the bark of the stem of Croton tiglium on the metabolism of the freshwater gastropod Lymnaea acuminata. American Malacological Bulletin 21(1–2): 87–92.

Sources of illustration

• van Welzen, P.C. & Esser, H.-J., 2001. Croton L. 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. 198–203.

Author(s)

• G.H. Schmelzer, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Schmelzer, G.H., 2007. Croton tiglium L. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 18 December 2024.

• See the Prota4U database.