Prota 11(1): Medicinal plants/Plantes médicinales 1
Adansonia 1: 105 (1861).
Synadenium pereskiifolium (Houllet ex Baill.) Guillaumin (1935).
Origin and geographic distribution
Euphorbia pereskiifolia occurs in Kenya and Tanzania.
In Kenya Euphorbia pereskiifolia is used by traditional doctors in the preparation of an anti-asthma drug. Although it is a highly poisonous plant, traditional doctors have used a leaf decoction, mixed with lemon juice, baking soda and honey, effectively in the treatment of asthma for decades with no adverse effects. The leaves are reported to be a strong purgative. In Tanzania women suffering from excessive menstruation drink the juice of fresh crushed leaves. Leprosy is treated with the ash of dried burnt leaves. The latex is highly irritating to the skin and mucous membranes, causing blisters and pain. Several peanuts dipped into the latex are eaten as a drastic purgative. Boils are treated with the latex. Roots also contain the strong latex, and a cold water extract of peeled roots is mixed with sugar and left standing for three days, after which it is drunk against heavy coughs and tuberculosis.
In addition to medicinal uses, the latex is an ingredient in arrow poison in Kenya. In Kenya and Tanzania the latex is used as fish poison.
Preliminary phytochemical screening of the aqueous extract of the leaves and stems revealed the presence of glycosides, terpenoids, flavonoids and other phenolic compounds.
An aqueous extract of the stems and leaves contracted the isolated guinea pig ileum. A glycoside, 2-O-β-D-glucopyranosyl-L-malic acid was isolated from the aqueous extract, but this was found to be inactive.
Monoecious, succulent shrub up to 5 m tall, laxly branched; stems cylindrical, with copious latex. Leaves arranged spirally, simple and usually entire; stipules modified into small brown glands; petiole winged, c. 1 cm long; blade obovate, up to 19 cm × 10 cm, base cuneate, apex obtuse to rounded, fleshy, glabrous, pinnately veined, midvein prominent beneath. Inflorescence an axillary false umbel, composed of 2–5 cymes, consisting of clusters of flowers, each cluster called a ‘cyathium’; peduncle up to 4 cm long and branches c. 2 cm long; bracts broadly ovate, c. 3.5 mm × 3 mm, short-hairy; cyathia with a funnel-shaped involucre c. 2.5 mm × 6 mm, densely short-hairy below, glandular rim c. 1 mm wide, deeply furrowed, greenish yellow, lobes c. 1.5 mm in diameter, margin hairy, each cyathium containing 1 female flower surrounded by several male flowers. Flowers unisexual; male flowers sessile with fan-shaped, fringed bracteoles, perianth absent, stamen c. 3 mm long; female flowers with pedicel up to 6 mm in fruit, perianth obtusely 3-lobed, ovary superior, 3-celled, styles 3, c. 2 mm long, fused to halfway, deeply bifid at apex. Fruit a 3-lobed capsule c. 7 mm × 7 mm, short-hairy, 3-seeded. Seeds ovoid, c. 2.5 mm × 2 mm, obtusely 4-angled, minutely rough, pale brownish grey, caruncle minute.
Euphorbia comprises about 2000 species and has a worldwide distribution. Synadenium (about 15 species in continental Africa) has classically been kept separate from Euphorbia, mainly because the glands of the cyathia form a ring in Synadenium, whereas the glands in Euphorbia are separate or only touching. However, recent molecular analyses found Synadenium to be nested within Euphorbia section Monadenium, and it is therefore now included in Euphorbia. Several other Euphorbia spp., belonging to section Monadenium, have medicinal uses. Euphorbia cupularis Boiss. (‘dead man’s tree’; synonym: Synadenium cupulare (Boiss.) L.C.Wheeler) occurs in Mozambique and South Africa. The latex is extremely toxic, irritant and blistering, and never taken internally. In South Africa ground dry leaves or ground leaves in water are sniffed to treat headache, catarrh and flu. Dried leaves are eaten to treat asthma. Latex is placed in a hollow tooth to treat toothache; latex is also rubbed on infected wounds. The burnt roots are used with other plants to treat paralysis. The bark is employed in a potent sorcery charm. An ethanolic leaf extract significantly inhibited prostaglandin-synthesis. Euphorbia neoglaucescens Bruyns (synonym: Synadenium glaucescens Pax) is a succulent tree endemic to Tanzania and morphologically similar to Euphorbia pereskiifolia; it has similar medicinal uses. The juice of fresh, crushed leaves is drunk to treat excessive menstruation and as a purgative; a leaf decoction with lime juice, baking soda and honey added is drunk to treat asthma. The ashes of dried leaves are mixed with water and applied to treat leprosy. A root bark extract is taken with sugar to treat severe cough and tuberculosis; a root extract is used as ear drops to treat earache. A few drops of latex are put on 1–2 peanuts and eaten as a purgative. The latex is also used as a fish poison.
Euphorbia pereskiifolia occurs on sandy soil or on rocks in coastal or riverine woodland, from sea-level up to 250 m altitude.
Euphorbia pereskiifolia is easily and quickly propagated by stem cuttings, which should be at least 20 cm long. After cutting they should be allowed to lie in a shaded place for at least a week for a callus to form on the cut end. Care should be taken that the latex does not touch the skin or mucous membranes because of its irritating properties. Euphorbia pereskiifolia can also be grown from seed. Mostly wild plants are used, or a few trees planted near villages, and no management practices are required.
Genetic resources and breeding
Although Euphorbia pereskiifolia only occurs in Kenya and Tanzania, there are no signs that it is threatened by genetic erosion. As a (semi-)succulent Euphorbia species, its trade is controlled under CITES appendix 2.
The use of Euphorbia pereskiifolia as a medicinal plant is not recommended because of its very toxic latex. Unless interesting pharmacological compounds are isolated, the species will remain of local importance as a medicine against asthma.
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Correct citation of this article:
Newton, L.E., 2008. Euphorbia pereskiifolia Houllet ex Baill. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(1): Medicinal plants/Plantes médicinales 1. [CD-Rom]. PROTA, Wageningen, Netherlands.