Prota 14: Vegetable oils/Ol้agineux
Flora 24(1): 370 (1841).
Origin and geographic distribution
Cephalocroton cordofanus occurs naturally in northern Nigeria, and from eastern Sudan east to Ethiopia and Eritrea, and south to north-eastern Tanzania.
The seeds, locally called dingili seeds, are eaten in eastern Sudan. They are rich in a highly unsaturated oil, which is occasionally extracted and used in cooking.
The seeds contain 42% oil, the kernel about 56%. The oil has a pleasant odour and taste. It consists chiefly of cis-12:13-epoxyoleic acid (62%) along with saturated acids (7%), oleic acid (10%), linoleic acid (17%) and 12:13-dihydroxyoleic acid (4%).
Monoecious, perennial much-branched shrub up to 3 m tall; taproot stout; bark dark grey; all parts covered with stellate hairs, young parts somewhat viscid. Leaves alternate, simple; stipules irregularly cleft with filiform segments, c. 2 mm long; petiole 12.5 cm long; blade broadly ovate-oblong to elliptical-ovate, (0.5)1.54(6) cm ื (0.5)12.5(4) cm, base rounded or shallowly cordate, apex acute to rarely obtuse, margins entire to toothed, papery, 57- veined from the base. Inflorescence a terminal raceme, with male flowers in a dense terminal globose cluster and 14 female flowers at base of peduncle; peduncle 26 cm long; bracts up to 3 mm long. Flowers unisexual, regular; petals absent; male flowers with pedicel up to 5 mm long and with 4 glabrous, elliptical-ovate sepals c. 2 mm ื 11.5 mm, white to pale greenish white, stamens 45, free, filaments c. 5 mm long, bright yellow, pistillode cylindrical, 2-lobed; female flowers sweet-scented, with pedicel up to c. 1.5 cm long and with 6 sepals, bipinnately lobed, c. 5 mm long, strongly enlarging in fruit, lobes linear, with side lobes, often flushed purplish red, ovary superior, c. 2 mm in diameter, 3-lobed and 3-celled, styles 3, fused at base, c. 7 mm long, cleft into many lobes, lime-yellow to ochre. Fruit a deeply 3-lobed capsule c. 12 mm in diameter, hairy, 3-seeded. Seeds ovoid to nearly globose, c. 7.5 mm ื 6 mm, smooth, evenly greyish or dark brown flecked and mottled, somewhat shiny.
Cephalocroton comprises 3 species in tropical Africa and South Africa. It is closely related to Adenochlaena (1 species from Madagascar and the Comoros and 1 from Sri Lanka) and Cephalocrotonopsis (1 species from Socotra), which are commonly included in Cephalocroton.
Cephalocroton cordofanus usually occurs on sandy soils, less often on clayey soils (including black cotton soil), in dried-out river beds, in seasonally waterlogged, open grassland and in mixed open bushland, up to 1200 m altitude.
The seeds are mainly collected from the wild, but occasional cultivation has also been reported.
Genetic resources and breeding
Cephalocroton cordofanus occurs only sparsely in its wide area of distribution. However, there are no indications that it is threatened by genetic erosion.
The presence of epoxy and hydroxy fatty acids in high concentrations make the oil an interesting raw material in chemistry. The physiology which leads to these high concentrations deserves research attention.
Bharucha, K.E. & Gunstone, F.D., 1956. Vegetable oils. V. Component acids of Cephalocroton cordofanus seed oil. Journal of the Science of Food and Agriculture 7: 606609.
Gilbert, M.G., 1995. Euphorbiaceae. In: Edwards, S., Mesfin Tadesse & Hedberg, I. (Editors). Flora of Ethiopia and Eritrea. Volume 2, part 2. Canellaceae to Euphorbiaceae. The National Herbarium, Addis Ababa University, Addis Ababa, Ethiopia and Department of Systematic Botany, Uppsala University, Uppsala, Sweden. pp. 265380.
Mansfeld, R., 1986. Verzeichnis landwirtschaftlicher und gไrtnerischer Kulturpflanzen (ohne Zierpflanzen). 2nd edition, revised by J. Schultze-Motel. 4 volumes. Springer Verlag, Berlin, Germany. 1998 pp.
Morris, L.M. & Holman, R.T., 1961. Naturally occurring epoxy acids: 2. Detection and measurement of long-chain epoxy acids by near infrared spectrophotometry. Journal of Lipid Research 2(1): 7782.
Radcliffe-Smith, A., 1987. Euphorbiaceae (part 1). In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 407 pp.
Bharucha, K.E. & Gunstone, F.D., 1956. Fatty acids. IV. Preparation of eight 9,10,12,13 tetrahydroxystearic acids. Journal of the Chemical Society 1956: 16111619.
Eckey, E.W., 1954. Vegetable fats and oils. Reinhold Publishing, New York, United States. 835 pp.
Gilliland, H.B., 1952. The vegetation of eastern British Somaliland. Journal of Ecology 40(1): 91124.
Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A., 2000. World checklist and bibliography of Euphorbiaceae (with Pandaceae). Royal Botanic Gardens, Kew, Richmond, United Kingdom. 1620 pp.
Henry, A.J. & Grindley, D.N., 1943. Investigation of the oil of the seeds of Cephalocroton cordofanus. Journal of the Society of Chemical Industry, London 62: 60.
Radcliffe-Smith, A., 1973. An account of the genus Cephalocroton Hochst. (Euphorbiaceae). Kew Bulletin 28(1): 123132.
Radcliffe-Smith, A., 2001. Genera Euphorbiacearum. Royal Botanic Gardens, Kew, United Kingdom. 455 pp.
Correct citation of this article:
Oyen, L.P.A., 2007. Cephalocroton cordofanus Hochst. In: van der Vossen, H.A.M. & Mkamilo, G.S. (Editors). PROTA 14: Vegetable oils/Ol้agineux. [CD-Rom]. PROTA, Wageningen, Netherlands.