654

19: Essential-oil plants

Cananga odorata (Lamk) Hook.f. & Thomson

Fl. ind. 1: 130 (1855).

ANNONACEAE

2n = 16

Uvaria odorata Lamk (1785), Canangium odoratum (Lamk) Baillon (1868), Cananga scortechinii King (1922).

Ylang-ylang, cananga, perfume tree (En). Ylang-ylang, cananga (Fr). Indonesia: kananga (general), kenanga (Javanese), sepalen (Moluccas). Malaysia: kenanga, chenanga, kenanga utan (wild forms). Philippines: ylang-ylang, ilang-ilang, alangilang. Burma (Myanmar): kadatngan, kadapgnam, sagasein. Cambodia: chhkè srèng. Thailand: kradangnga-thai (central), kradangnga-songkhla (central, var. fruticosa), sabannga-ton (northern). Vietnam: ng[oj]c lan t[aa]y, ho[af]ng lan, ylang ylang.

Cananga odorata is thought to originate from South-East Asia and occurs naturally throughout South-East Asia, Australia and several Pacific islands. It has been introduced into China, India, Africa and the Americas. Commercial cultivation of Cananga odorata for the production of ylang-ylang oil started in the Philippines, later followed by the production of cananga oil in Indonesia. The First World War almost destroyed ylang-ylang cultivation in the Philippines, only one plantation continuing cultivation until the Second World War. In the Philippines Cananga odorata is now a smallholder crop grown almost exclusively for local use. In 1770 Cananga odorata was brought from the Philippines to Réunion, where commercial production of ylang-ylang oil started a century later. Production grew steadily, but declined sharply during the First World War; it never recovered and production virtually ceased during the economic depression of the 1930s. In the beginning of the 20th Century Cananga odorata was introduced into the Comoro Islands, where an important industry developed. Production peaked during the 1980s, but then declined due to the development of tourism and expansion of food production. Similarly, an ylang-ylang industry developed in the northern Madagascan island Nosy Bé; it peaked around 1950 and then gradually declined. In Guangdong Province in southern China, production started recently and is still expanding. Indonesia, the Comoro Islands and Nosy Bé are the main exporters of ylang-ylang oil. Java is the main producer of cananga oil; outside Java, the production of cananga oil is only important in Fiji.

The fragrant flowers of Cananga odorata are used for personal adornment and decoration at festivities and other celebrations. Malaysians and Indonesians are very fond of the scent, and the women like to hide a flower in their hair. Fresh flowers of Cananga odorata mixed with flowers of Jasminum sambac (L.) Aiton, Rosa spp., Michelia champaca L. and leaves of Pandanus amaryllifolius Roxb. are used in various ceremonies in Java and Bali. The flowers are also put away with clothes, or scattered about the bed. The Thai apply an infusion of the flowers on the body after bathing. Two forms of Cananga odorata are grown commercially: cv. group Ylang-ylang, which produces ylang-ylang oil and cv. group Cananga yielding cananga oil. Both oils are distilled from the flowers. Ylang-ylang oil and cananga oil are used to supply the dominant odour note of many perfumes. 'Extra' quality ylang-ylang oil is much used in high-class perfumery; 'Third' grade ylang-ylang oil and cananga oil have a harsher, more tenacious odour and are mainly used in soaps and toiletries for men. Both oils are sometimes used in foods and beverages. Cananga oil mixed with coconut oil is used as a hair oil named Macassar oil (this oil differs from the seed oil from Schleichera oleosa (Lour.) Oken that is also called Macassar oil).
Cananga odorata has several uses in traditional medicine. The dried flowers are used in Java against malaria and the fresh flowers are made into a paste for treating asthma. In Perak the leaves are rubbed on the skin against itch, and in West Java the bark is applied against scurf. The seed used to be used externally to cure intermittent fever.
In Malaysia, Cananga odorata is mainly planted as a roadside shade tree. The timber is white to grey, non-durable and mainly used for boxes. It has potential for making small drums and matchsticks. The bark can be beaten to make coarse ropes; this is done in Sulawesi.

In the late 1980s the value of world production of ylang-ylang oil was about US$ 7 million, compared with about US$ 1.35 million for cananga oil. Indonesia is by far the most important exporter of cananga oil, and the oil is known in international trade as Java cananga oil. In 1995 Indonesia cultivated about 160 000 ha cananga, producing 120 t oil. In many countries flowers are the main product and they are traded only locally.

Both cananga oil and ylang-ylang oil are obtained by distillation of the flowers of Cananga odorata; cananga oil from cv. group Cananga (forma macrophylla), ylang-ylang oil from cv. group Ylang-ylang (forma genuina). In the Comoro Islands and Nosy Bé ylang-ylang concrete is produced by petroleum ether extraction of the flowers. A volatile oil can be distilled from the leaves but it has no economic value. Whereas cananga oil is traded as a complete oil, ylang-ylang oil is fractionated into different grades; in Madagascar 4 qualities are recognized: 'Extra', 'First'', 'Second' and Third'. An additional grade, 'Premier' quality, is only produced to order. 'Extra' and 'First' are used mostly in fine perfumery, 'Second' and 'Third' in soap perfumery; 'Extra' and 'Third' are most important in trade.
Ylang-ylang oil 'Extra' is the first and most volatile fraction containing 20—40% of the total distillate. It is a stable, pale yellow, mobile liquid. It has a floral top note, a floral, fruity, spicy body, and a light flowery, balsamic powdery dry-out lasting about 48 hours. The main chemical components are: (E,E)-farnesene, benzyl acetate, linalool, 'DELTA'-cadinene, p-methylanisole, 'BETA'-caryophyllene, methyl benzoate, benzyl benzoate, geranyl acetate. It is used as a lifting agent in high-quality perfumes of floral, floral aldehydic, chypre and Oriental types. 'Third' grade ylang-ylang is a clear, yellow, somewhat oily liquid. Its odour is tenacious, sweet and floral and different from 'Extra' quality oil for which it is not a substitute. Its main chemical components are: (E,E)-farnesene, 'BETA'-caryophyllene, 'ALFA'-humulene, 'DELTA'-cadinene, 'GAMMA'-cadinene, benzyl benzoate, linalool, geranyl acetate, (E)-nerolidol. Several samples of ylang-ylang oil from Yunnan, southern China were found to be remarkably rich in 'GAMMA'-muurolene.
Cananga oil is a stable, yellow to greenish-yellow, mobile liquid. It has a floral, woody, medicated top note, a sweet, floral, medicated body and a sweet floral dry-out lasting 24 hours. Its main chemical components are: 'BETA'-caryophyllene, 'ALFA'-humulene, (E,E)-farnesene, 'GAMMA'-cadinene, 'DELTA'-cadinene, benzyl benzoate, linalool, geranyl acetate. It is used largely in soap perfumery, in floral fragrances such as jasmine, lilac and hyacinth and also in Oriental-type perfumes.
Ylang-ylang oil blends well with bois de rose oil, methyl salicylate, phenylethyl cinnamate and vetiver oil. It is much used as a modifier in artificial violet and lilac perfumery products. It may be fixed with any of the synthetic or natural plant gums and resins. Important minor components contributing to the odour of ylang-ylang oil and cananga oil are p-cresol, eugenol and isoeugenol. Hypersensitivity to cosmetics containing ylang-ylang or cananga oils attributed to eugenol and related compounds has been reported.
Commercial ylang-ylang absolute is usually a mixture of 2 types of absolutes obtained from the flowers. The first type is obtained by alcohol washing the concrete obtained by solvent extraction. The exhausted flowers from this extraction are steam distilled and the essential oil obtained is washed with alcohol to produce the second type. Both the absolute and the concrete have the true scent characteristics of the flowers. The absolute is very powerful, intense sweet floral and is used in very small concentrations in high-quality perfumes. The taste is bitter, but can be modified for use in sweets and drinks. The main chemical components of the absolute are: (E,E)-farnesene, linalool, benzyl benzoate, 'DELTA'-cadinene, 'BETA'-caryophyllene, benzyl salicylate, geranyl acetate, methyl benzoate, 'ALFA'-humulene. The Food and Drug Administration of the United States has given ylang-ylang and cananga oil the 'generally recognized as safe' (GRAS) status in alcoholic beverages, bakery products, candies, chewing gum, puddings and soft drinks at levels up to 5 ppm for ylang-ylang oil (GRAS No 3119) and 32 ppm for cananga oil (GRAS No 2232). See also: Composition of essential-oil samples and the Table on standard physical properties.

The flowers of climbing ylang-ylang (Artabotrys uncinatus (Lamk) Merrill) are sometimes mixed with true ylang-ylang flowers as adulterants. They bear some resemblance to true Cananga odorata flowers and are also fragrant.

An evergreen tree, 10—40 m tall, in cultivation often pruned to 3 m; trunk up to 75 cm in diameter, without buttresses; bark pale grey or silvery, smooth. Branches drooping, or slightly erect with dangling leafy twigs; young twigs minutely pubescent, glabrescent. Leaves alternate, distichous, simple, exstipulate; petiole slender, 1—2 cm long, narrowly grooved, glabrous; blade elliptical to ovate-oblong, 13—29 cm x 4—10 cm, base often oblique, rounded cordate, margin more or less undulating, apex acutely acuminate, membranous, midrib and lateral veins mostly whitish-pubescent on both sides, secondary veins in 8—9 pairs, clearly visible on both sides, often with small, hairy, pitted glands in vein axils. Inflorescence a raceme, 1—4 cm long, with 2—6 flowers on short, leafless, axillary shoots, dangling in clusters of 1—3 from the older branches behind the leaves; flowers 5—7.5 cm long, bisexual, green turning light dull yellow, overpoweringly fragrant when mature; pedicel 2—5 cm long; sepals 3, ovate, 5—7 mm x 5 mm, reflexed; petals 6, in 2 whorls of 3, linear-lanceolate, 3—9 cm x 5—16 mm, often curled or wavy, with purple brown spot at the base inside; stamens numerous, closely arranged, linear, 2—3 mm long, with a broad, cone-shaped appendix of the connective; staminodes absent; carpels many, with slender style and discoid stigma. Fruit pendulous, consisting of many (7—16) separate, globose-obovoid monocarps, about 2.5 cm x 1.5 cm on stalk 1—2 cm long; monocarp dark green, ripening blackish, 2—12-seeded, with seeds embedded in yellow oily pulp arranged in 2 rows. Seed flattened, ellipsoid, 9 mm x 6 mm x 2.5 mm, pale brown, surface pitted, hard, with a rudimentary aril.

At sea-level, saplings of cultivated trees of Cananga odorata flower when 1.5—2 years old and 2 m tall; at 500 m altitude flowering may start only after 7 years. Wild trees do not flower until they are 9—12 m tall. When the buds open, the flowers are not yet fragrant and the petals are green and covered with white hairs; the petals enlarge, become glabrous and turn from green to yellow after 15—20 days and then the flowers emit their powerful and agreeable odour, discernable at a distance. Both cultivated and wild trees flower throughout the year, but with marked seasonal peaks after periods of dry weather. In Peninsular Malaysia there is regular flowering for several weeks between February and May and often a second flowering between August and October. In Java there are 3—4 peaks in flowering; flowering is most abundant at the end of the rainy season, while flowers are richer in oil during the dry season. The oily fruits are eaten by squirrels, bats, monkeys and birds, by which means the seed is dispersed. A well managed plantation may remain productive for 50 years.

The habit of Cananga odorata is typically a straggling, pendulous tree: branches and leaves droop, long leafy sprays may dangle for a length of 3—6 m, flowers hang in loose bunches, and the petals are flaccid. Although the trunk continues to the top of the tree, it is commonly bent. A dwarf variety of Cananga odorata known as var. fruticosa (Craib) Sinclair, is often seen in tropical gardens. It is a bush 1—1.5 m tall, with frequently supernumerary, very curly petals. It flowers throughout the year, but never sets fruits. It probably originates from Thailand. Two groups can be distinguished in cultivated Cananga odorata: cv. group Cananga (forma macrophylla Steenis), flowers are the source of cananga oil; branches perpendicular to the stem; leaves 20 cm x 10 cm; cultivated in Java, Fiji and Samoa; and cv. group Ylang-ylang (forma genuina Steenis), the source of ylang-ylang oil; branches more drooping; leaves smaller; probably originating from the Philippines and cultivated throughout the tropics.

Cananga odorata thrives in the more humid lowland tropics with an annual rainfall of (650—)1500—2000(—4000) mm and an average annual temperature of 21—27°C. In Java it grows gregariously in moist evergreen forest and in teak forest. In New Guinea it grows up to 850 m altitude. When planted it is found up to 1200 m. It grows well on light, well-drained soils with pH 4.5—8, preferring rich volcanic or fertile sandy soils. Because of the long taproot, deep soils are required. Waterlogging for prolonged periods, but not permanent marshy conditions are tolerated; saline and alkaline soils should be avoided.

Propagation of Cananga odorata is by seed or wildlings. Fresh seed germinates erratically; after 6—12 months storage the germination rate is higher. Hot water treatment of seed is used successfully in Nosy Bé. Vegetative propagation by stem cuttings and budding have been tried with varying success. Plants may be raised in nursery beds, but should be handled with great care during transplanting to avoid damage to the long taproot. Direct sowing is common and seed is placed 5 cm deep in well-cultivated and fertilized planting pits of at least 50 cm depth. Plant spacing is at least 6 m x 6 m.

Young plantations of Cananga odorata are often intercropped with food crops. Ring weeding and slashing of the inter-rows are important for optimal growth. For ylang-ylang production, trees are usually topped at about 3 m after 2—3 years. Topping promotes the growth of low, drooping branches, which are also tied down to pegs to keep the flowers within easy reach. In traditional production of cananga oil, often in home gardens, the trunk is left to grow. A well-managed plantation may remain productive for 50 years.

Very little is known about diseases and pests of Cananga odorata. Stem borers, flower-eating beetles and insects that cause the leaves to wilt have been reported.

A first small harvest of Cananga odorata may be taken in the second year, but profuse flowering starts in the 4th or 5th year. Flowers are picked individually 15—20 days after opening, when they have turned yellow and their smell has become strong. The appearance of a small purple-brown spot at the base of the petals indicates that flowers are ready for picking. Picking is done early in the morning up to 10 a.m., as strong sunlight rapidly diminishes the oil content. Only ripe flowers should be picked as immature ones have not yet developed their full smell and reduce the quality of the oil. Flowers are picked manually, long-handled cutters being used to reach flowers higher up in the tree. Ladders are needed in large trees; they should be used with great care as the branches are very brittle. Chemical removal of flowers using ethylene is possible, but is not yet practised. Rain has little direct effect on flower quality but diminishes the efficiency of the distillation process.

A fully developed, well managed tree will produce 30—100 kg flowers per year, but topped trees of cv. group Ylang-ylang rarely produce more than 20 kg. The flowers contain about 1—2% volatile oil.

As soon as the flowers of Cananga odorata are plucked they should be distilled. If distillation has to be postponed, flowers should be spread thinly in the shade as it is essential to avoid fermentation. Wilting or delayed distillation reduces oil yield but has little effect on oil composition. Steam distillation is the most common method of extraction; extraction with petroleum ether or benzene is occasionally used. Distillation is mostly done in direct-fired water stills; heating the water to near-boiling point before adding the flowers results in higher quality oil. To avoid spot-fermentation and overheating, stills should not be overcharged. The distillation process of ylang-ylang oil should be carefully controlled so that different fractions match grade standards.
A modern still yields about 2% oil, about 25% being 'Extra' or 'First' grade. Small traditional stills yield about 1% oil. Prolonged distillation may increase yield, but the oil so obtained is of poor quality. Small operators producing cananga oil frequently prolong distillation, merely removing spent flowers and topping up water. This reduces the oil quality, as unwanted compounds react with the desired esters.

No systematic collection work has yet been done and only very small collections of germplasm of Cananga odorata exist. In the Philippines, wild plants are threatened by extinction. No breeding programmes are known to exist.

Artificial cananga and ylang-ylang oil can be compounded at the price of ordinary cananga oil, with many times its strength. Modern perfumes, however, contain only the finest, natural ylang-ylang oil, while the demand for cananga oil, especially for toiletry products, is still growing. If a reliable supply of cananga and ylang-ylang oil can be assured, the demand for both will probably remain strong. Germplasm collection and agronomic research is strongly recommended.

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Umi Kalsom Yusuf & V.O. Sinohin

Yusuf, U.K. & Sinohin, V.O., 1999. Cananga odorata (Lamk) Hook.f. & Thomson. In: L.P.A. Oyen and Nguyen Xuan Dung (Editors): Plant Resources of South-East Asia No 19: Essential-oil plants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea