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Crocus sativus L.

Protologue
Sp. pl. 1: 36 (1753).
Family
Iridaceae
Chromosome number
2n = 24
Vernacular names
Saffron, crocus (En). Safran, safran vrai (Fr). Açafrão, açaflor, croco (Po).
Origin and geographic distribution
Crocus sativus is known only as a cultivated plant. It probably originated in Greece and western Asia, where some wild species occur which are possibly related. In very ancient times it was spread eastward to Kashmir in India. Later its cultivation spread to European temperate countries, western Asia, northern India and China. In tropical Africa saffron is rarely cultivated, but there are reports from the Hoggar area in southern Algeria and northern Mali. Its bulbs are imported occasionally, e.g. they are for sale on markets in Mauritius.
Uses
The dried upper part of the yellow style with 3 red stigmas attached, picked from the flowers of Crocus sativus, is the saffron of commerce, which is used mainly to colour and flavour foods. Saffron was also applied in textile dyeing, but only rarely and only for precious silks and special uses (e.g. women’s underwear).
Medicinally, saffron is considered an anodyne, antispasmodic, aphrodisiac, diaphoretic, emmenagogue, expectorant and sedative, but the many therapeutic properties of saffron are disputed. In traditional medicine it is used against scarlet fever, smallpox, colds, insomnia, depression, asthma and tumours. Saffron is an important ingredient in Ayurvedic and other systems of medicine in India. In Mauritius a paste of the bulb is applied to skin affections. Crocus sativus is widely planted as an ornamental in gardens.
Production and international trade
Crocus sativus is by far the world’s most expensive fooddye and spice. Spain has long been the main producer, accounting for 90% of the world’s production, but a large proportion of the export of Spain originates from plants actually grown in Iran. Other exporting countries are India (Kashmir), France, Italy and Algeria. The annual production in India at the beginning of the 1980s was estimated at 9–10 t. The international market price in that period was about US$ 1000 per kg.
Properties
The chief colorants of Crocus sativus are the yellowishred carotenoid glycoside crocin and the bitter glycoside picrocrocin. On hydrolysis crocin yields the sugar gentiobiose and crocetin. Saffron also contains the pleasantly smelling safranal, which develops during the drying process by enzymatic or thermal dissociation of picrocrocin.
In animal tests crocetin improved oxygenation in cases of haemorrhage, showed positive results in the treatment of atherosclerosis and arthritis, and inhibited the development of chemically induced skin tumours. In a pilot double-blind randomized clinical trial in Iran, saffron was found to be effective in a way similar to imipramine in the treatment of mild to moderate depression.
Botany
Small stemless perennial herb up to 30 cm tall, having a more or less globular subterranean corm 3–5 cm in diameter, surrounded by a finely reticulatefibrous tunic and rooting at base. Leaves linear, 1.5–2(–3) mm broad, with a white median stripe above, keeled below. Flowers 1–3, bisexual, regular, each on a short subterranean pedicel, subtended by membranous bracts; perianth with a long cylindrical tube and 6 segments 2.5–5 cm × 1–2 cm, deep lilacpurple or mauve coloured with darker veins, white or lilac in the throat; stamens 3; ovary inferior, style divided into 3 brilliant orangered stigmas 2.5–3.5 cm long.
Crocus comprises about 80 species and occurs from Europe to central Asia. Crocus sativus is a sterile triploid which reproduces only vegetatively. The corms reproduce annually, giving rise to new young cormlets. Being very expensive saffron is often adulterated in a variety of ways. Not only is very impure saffron consisting of floral parts other than stigmas sold, but parts of other plant species with dyeing properties are also offered under the name ‘saffron’, such as powdered rhizomes of turmeric (Curcuma longa L.), and flowers of safflower (Carthamus tinctorius L.). The dyeing substances from these plants can be used in the same way as true saffron, and are much cheaper. In East and southern tropical Africa the yellow dye obtained from the flowers of Crocosmia aurea (Pappe ex Hook.) Planch. can be used as a substitute for saffron. Crocosmia aurea is also used in traditional medicine, e.g. leaf sap and a decoction of the corm is drunk to treat malaria, and a root decoction is drunk to treat arthritic rheumatism, for which purpose the ash of the plant with Ricinus oil is also embrocated into scarifications.
Ecology
Crocus sativus thrives best in temperate and fairly dry climates. In the areas of Spain where saffron is cultivated, annual rainfall only rarely exceeds 400 mm. Two periods of heavy rainfall are adequate for good yields, one in spring for the production of new corms and a second at the end of summer to promote flowering. Crocus sativus flowers in autumn. Frosts or rains during flowering are harmful and can damage the crop.
Management
Propagation is by means of corms. Cultural practices vary for the different producing countries. Once planted, corms may remain in the field for 3–12 years, but sometimes saffron is grown as an annual crop. The flowering and harvesting season lasts for about 4 weeks. The flowers must be picked in the early morning, and the stigmas should be removed on the same day. The 3 stigmas are dried, along with about 5 cm of the style attached, and constitute the pure saffron of commerce. An average yield is about 1 million flowers per ha, which in turn produces 10 kg dried saffron. Firedried saffron is more valuable than sundried. Saffron is marketed both as a powder and as the much less dense ‘hay saffron’, i.e. loose stigmas. Quality is maintained by storage at low humidity.
Genetic resources and breeding
Crocus sativus has been shown to be genetically homogeneous throughout its region of cultivation, from Spain to China, as a result of continued vegetative propagation of a single clone.
Prospects
As it is not suited to tropical and highrainfall climates, Crocus sativus does not have good prospects in tropical Africa. However, as saffron is valued in parts of the region and as products from other plant resources are often confused with true saffron, it seemed useful to give some attention to this species.
Major references
• Basker, D. & Negbi, M., 1983. Uses of saffron. Economic Botany 37(2): 228–236.
• 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.
• Wessel-Riemens, P.C., 1991. Crocus sativus L. In: Lemmens, R.H.M.J. & Wulijarni-Soetjipto, N. (Editors). Plant Resources of South-East Asia No 3. Dye and tannin producing plants. Pudoc, Wageningen, Netherlands. pp. 67–69.
Other references
• Adjanohoun, E.J., Aké Assi, L., Eymé, J., Gassita, J.N., Goudoté, E., Guého, J., Ip, F.S.L., Jackaria, D., Kalachand, S.K.K., Keita, A., Koudogbo, B., Landreau, D., Owadally, A.W. & Soopramanien, A., 1983. Médecine traditionelle et pharmacopée - Contribution aux études ethnobotaniques et floristiques à Maurice (Iles Maurice et Rodrigues). Agence de Coopération Culturelle et Technique, Paris, France. 216 pp.
• Akhondzadeh, S., Fallah-Pour, H., Afkham, K., Jamshidi, A.H. & Khalighi-Cigaroudi, F., 2004. Comparison of Crocus sativus L and imipramine in the treatment of mild to moderate depression: a pilot double-blind randomized trial. BMC Complementary and Alternative Medicine 4(1): 12.
• Giaccio, M., 2004. Crocetin from saffron: an active component of an ancient spice. Critical Reviews in Food Science and Nutrition 44(3): 155–172.
• Sampathu, S.R., Shivashankar, S. & Lewis, Y.S., 1984. Saffron (Crocus sativus Linn.). Cultivation, processing, chemistry and standardization. CRC Critical Reviews in Food Science and Nutrition 20(2): 123–157.
Sources of illustration
• Wessel-Riemens, P.C., 1991. Crocus sativus L. In: Lemmens, R.H.M.J. & Wulijarni-Soetjipto, N. (Editors). Plant Resources of South-East Asia No 3. Dye and tannin producing plants. Pudoc, Wageningen, Netherlands. pp. 67–69.
Author(s)
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Based on PROSEA 3: ‘Dye and tannin-producing plants’.

Editors
P.C.M. Jansen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
D. Cardon
CNRS, CIHAM-UMR 5648, 18, quai Claude-Bernard, 69365 Lyon, Cedex 07, France
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Jansen, P.C.M., 2005. Crocus sativus L. In: Jansen, P.C.M. & Cardon, D. (Editors). PROTA 3: Dyes and tannins/Colorants et tanins. [CD-Rom]. PROTA, Wageningen, Netherlands.
1, plant habit; 2, opened flower; 3, style and stigmas; 4, stigma
Source: PROSEA