Cinnamomum is a large genus, many species of which yield a volatile oil on distillation. The composition of the oil, and therefore its value and the use to which it is put, depends very much on the species that is distilled as well as the part of the plant which is utilized. The most important Cinnamomum oils in world trade are those from C. verum (cinnamon bark and leaf oils), C. cassia (cassia oil) and C. camphora (sassafras and Ho leaf oils). The latter species provides oils which are utilized as sources of chemical isolates.
However, a number of other Cinnamomum species are distilled on a much smaller scale and the oils used either locally or exported to regional markets. Given the large number of Cinnamomum species that exist, their widespread distribution in Asia, and the number still not characterised in terms of essential oil content and composition, the genus has much potential for providing new tree crops in developing countries.
The spice oils cinnamon and cassia are discussed first. An indication is then given of the types of oil found in other Cinnamomum species, including C. camphora, and those with the greatest perceived potential for future use.
Cinnamon bark oil possesses the delicate aroma of the spice and a sweet and pungent taste. Its major constituent is cinnamaldehyde but other, minor components impart the characteristic odour and flavour. It is employed mainly in the flavouring industry where it is used in meat and fast food seasonings, sauces and pickles, baked goods, confectionery, cola-type drinks, tobacco flavours and in dental and pharmaceutical preparations. Perfumery applications are far fewer than in flavours because the oil has some skin-sensitizing properties, but it has limited use in some perfumes.
Cinnamon leaf oil has a warm, spicy, but rather harsh odour, lacking the rich body of the bark oil. Its major constituent is eugenol rather than cinnamaldehyde. It is used as a flavouring agent for seasonings and savory snacks. As a cheap fragrance it is added to soaps and insecticides. The oil's high eugenol content also makes it valuable as a source of this chemical for subsequent conversion into iso-eugenol, another flavouring agent.
Cassia oil is distilled from a mixture of leaves, twigs and fragments of bark. Cinnamaldehyde is the major constituent and it is used mainly for flavouring cola-type drinks, with smaller amounts used in bakery products, sauces, confectionery and liqueurs. Like cinnamon bark oil, its use as a fragrance is limited by its skin sensitizing properties.
Cinnamon bark oil is a high-value essential oil but the volumes traded are very low. In the ten years since 1983 exports from Sri Lanka, virtually the only supplier of the oil, have never been more than 2.8 tonnes. Exports from Sri lanka for the six years 1987-92, together with their destinations, are shown in Table 1.
The major market is the EC, within which France is the biggest importer. In recent years the United States has emerged as the second largest importing country.
World demand for cinnamon leaf oil has been around 120-150 tonnes pa in recent years, met almost entirely by Sri Lanka. Sri Lankan exports (Table 2) have averaged about 120 tonnes pa for the period 1987-92, but this includes an exceptionally low output in 1990.
The United States and Western Europe are the largest markets for cinnamon leaf oil. Imports into France and the UK have fallen in the last few years, as they have slightly for India. Hong Kong is a significant importer although most of the oil is re-exported.
The ready availability of eugenol ex clove leaf oil has led to some loss in markets for cinnamon leaf oil. When eugenol is required for further conversion into iso-eugenol, that produced from cinnamon leaf oil possesses a more desirable aroma and flavour than when derived from clove leaf oil. For most other purposes, however, the cheaper eugenol ex clove leaf oil is preferred.
Estimation of world demand for cassia oil is complicated by the fact that export data are not available from the People's Republic of China, the major producer. Furthermore, the oil is only separately specified in import statistics of the USA and Japan, although these are known to be the major markets.
The levels of imports of cassia oil into the USA are shown in Table 3 for the period 1987-93.
Imports into the USA have risen in recent years and, with a soft drinks market which shows no sign of weakening, demand for cassia oil is expected to remain strong. Imports from Japan and Hong Kong are almost entirely re-exports of Chinese oil.
Japanese imports of cassia oil have averaged 60 tonnes pa for the six years 1988-93, virtually all of it coming directly from the People's Republic of China. A significant proportion of the imports are re-exported (to the USA, for example, above).
Sri Lanka is the only regular supplier of cinnamon bark and leaf oils. With the exception of 1990, when both oils were in short supply, production (as reflected in exports) has remained very constant for bark oil, with a slight downward trend for leaf oil. Internal consumption is small so that production levels are not much greater than exports.
Madagascar and the Seychelles have been intermittent suppliers of leaf oil on a very minor scale in the past. India produces very small amounts of leaf oil for domestic use.
Most cassia oil in international trade is of Chinese origin. There is believed to be significant domestic consumption so total annual production may be in excess of 500 tonnes.
Small quantities of cassia oil are produced in Indonesia, Viet Nam, India and Nepal but these are obtained from species of Cinnamomum other than C. cassia (see PLANT SOURCES) and are much less widely traded than Chinese oil.
There is no international standard for cinnamon bark oil although batches containing cinnamaldehyde at the higher end of the range fetch the higher price. In the United States, an EOA standard specifies an aldehyde content of 55-78 percent.
International (ISO) standards exist for cinnamon leaf and cassia oils. For cinnamon leaf oil, ranges between which the major constituent, eugenol, should fall are specified in terms of total phenol content for oils of different origin. Oil from the Seychelles used to be preferred because of its high eugenol content (ca 90 percent). In practice, Sri Lanka now accounts for almost all of the oil in international trade and the standard specifies a 75-85 percent phenol content. Another constituent of the oil which contributes to its aromatic character is cinnamaldehyde and for Sri Lankan oil a maximum level of 5 percent is specified. Physico-chemical requirements are also given.
In the United States an FMA monograph, which replaces the old EOA standard, specifies the eugenol content of cinnamon leaf oil in terms of its solubility in potassium hydroxide (80-88 percent).
For cassia oil, cinnamaldehyde is the major constituent and a minimum content of 80 percent is specified in the ISO standard. Again, physico-chemical data are provided.
Cinnamon bark oil is considerably more expensive than the leaf oil and probably the most highly priced of all essential oils. During 1992 it was being offered at around US$385/kg, largely reflecting the high raw material cost. In 1993 and early 1994 dealers in London were only quoting prices on request.
Cinnamon leaf oil, in contrast, has been in the range US$6.50-7.50/kg for most of the last three years. Its price fell gradually from about US$7.50 in early 1991 to US$6.50 in mid-1993. In late 1993 it had risen again to US$7.30/kg and in early 1994 it was US$8.25/kg. Although it is a comparatively low-priced oil it is still more expensive than clove leaf oil as a source of eugenol (which was approximately US$2.70/kg in early 1994).
Cassia oil, too, has remained fairly level in price over the last few years. In the period early 1991 to mid-1993 it fetched US$33-35/kg. It then fell slightly and in early 1994 it was about US$29/kg. These prices are significantly lower than those which prevailed in the early and mid-1980s, when there was a shortage of cassia bark in the People's Republic of China. Any appreciable rise in price above the US$30-35/kg level is likely to encourage end-users to blend cheaply available synthetic cinnamaldehyde with natural cassia oil.
|Cinnamomum verum Presl (syn. C. zeylanicum Nees)||True or Ceylon cinnamon|
|C. cassia Presl||Cassia, Chinese cinnamon, "Cassia lignea"|
|C. burmannii Blume||Indonesian cassia|
|C. loureirii Nees||Vietnamese cassia|
|C. tamala (Buch.-Ham.) Nees & Eberm.||Indian cassia|
The genus Cinnamomum comprises several hundred species which occur naturally in Asia and Australia. They are evergreen trees and shrubs and most species are aromatic. C. verum, the source of cinnamon bark and leaf oils, is a tree indigenous to Sri Lanka, although most oil now comes from cultivated areas. Smaller areas of wild trees are found in southwestern parts of India. C. cassia, the source of internationally traded cassia oil, occurs wild as a bush in the mountains of southern China but is now cultivated for oil production, mainly in the provinces of Kwangsi and Kwangtung.
The other cassias occur wild on the islands of Sumatra and Java, Indonesia (C. burmannii); in Viet Nam (C. loureirii); and India and Nepal (C. tamala). In all cases the trees are also cultivated.
Effects of oil production on the natural resource
Most of the above oils are now derived almost entirely from cultivated sources and there is no longer pressure on the wild resource.
Cinnamomum usually coppices well and commercial production of the bark spices entails cutting the stems low down after an initial establishment period and harvesting the bushy re-growth stems at regular intervals thereafter. In Sri Lanka, a first harvest may be obtained after 3-4 years, although both quality and yields improve with subsequent cutting. The stems are cut during the rainy season to facilitate peeling of the bark. Details of harvesting practice differ slightly from country to country but the basic principles are the same. Strips of bark are then formed into the familiar compound quills (cinnamon) or hollow quills (cassia) of the spices.
In Sri Lanka, cinnamon bark oil is produced by distillation of chips and variable amounts of featherings (pieces of inner bark from twigs and twisted shoots) and quillings (broken fragments of quills). In many cases the older form of hydro-distillation is used in which chips and water are placed together in the distillation vessel which is heated by direct fire. The oil distils over in two fractions, one lighter and one heavier than water, and a form of cohobation is used to recover residual oil from the distillation waters. More modern methods involve steam distillation.
The leaves left after trimming the cut stems, as well as those obtained from pruning operations, provide the raw material for production of cinnamon leaf oil. They are usually allowed to dry for a few days before distillation. Traditional stills in Sri Lanka are large wooden vessels capable of holding up to 200 kg of leaves, on top of which is fitted a copper still head. Steam is introduced from a separate wood-fired boiler. In some cases, all-metal vessels are used and water-steam distillation is employed.
Chinese cassia oil is produced by hydro-distillation of leaves, twigs and fragments of bark.
For cinnamon and cassia oils there is more potential than usual for variation in oil yields and quality and this makes it difficult to cite typical data. Not only is there the expected intrinsic variation due to different geographical origins of the source raw material, but the composition of the charge that is distilled is liable to vary, particularly in the case of cinnamon bark oil and cassia oil. The method of distillation used (steam vs water-steam vs hydro-distillation) and other differences in distillation practice give rise to further causes of variation.
Cinnamon and cassia oils are both normally rectified within the importing country before sale to end-users in order to give a cleaner product or to provide an oil with more uniform composition. Rectification is also required to produce feedstock eugenol for subsequent derivative manufacture.
The major incentive to cultivation of C. verum and C. cassia has been their value as spice crops, for which world demand is considerable (tens of thousands of tonnes of bark annually). Indonesian cassia (C. burmanii) is much more important as a spice than as a source of oil and enters international trade along with Chinese cassia. There is some production of oleoresin for flavouring purposes, chiefly in North America from the cheaper Indonesian cassia. Bark also finds local use medicinally, particularly in the People's Republic of China.
For the cinnamon and cassia oils of international commerce, production of oil is secondary to the production of the spice. The establishment of new areas of these particular Cinnamomum species will depend upon demand for the spice and economic returns to the farmer. Whether "waste" material from spice production is then utilized for oil production is, again, dependent on demand, prevailing oil prices and economic returns. The close relationship between the two commodities makes it unlikely that production of oil will shift, geographically, from the traditional centres of spice production.
Apart from improvements in distillation practice, the greatest advances in productivity and quality will come from breeding programmes aimed at producing superior germplasm for planting. Some progress has already been made in identifying mother plants which give high yields of oil and high cinnamaldehyde and eugenol contents in the bark and leaves (GURUSINGHE and KIRINDE, 1985) and this work needs to be continued.
The diversity of Cinnamomum as a genus, although not as great as, say, Eucalyptus, has analogies with the latter in terms of the variety of chemical types of volatile oil that may be distilled from the plants. Like Eucalyptus, the same species of Cinnamomum can afford oils with quite different compositions according to the population being studied, i.e. it may exist as different chemotypes. C. camphora is a well-known example and the wood from different groups of trees may yield camphor, linalool, safrole or cineole as the major chemical upon distillation.
This diversity, coupled with the ability of most Cinnamomum to respond to coppicing (a system of management which enables it to be harvested on a sustainable basis), and a market that is always receptive to new, alternative sources of natural aroma chemicals, makes Cinnamomum one of the most promising areas for research. The increasing number of reports in the scientific literature describing the oil characteristics of Cinnamomum species is evidence of the attention they are receiving in screening programmes.
Table 4 gives some examples of Cinnamomum species which are, or might be, used as sources of commercially valuable chemical isolates.
C. camphora was heavily exploited as a source of camphor in Japan and Taiwan until the Second World War. Trees were felled and logs, stumps and branches distilled to give crystalline camphor and camphor oil. The species was introduced into India during the 1950s. Although yields of camphor are greater for old trees, leaves and woody material can be harvested regularly from plants over five years of age which are kept in a bushy form by coppicing. This form of harvesting is carried out in the People's Republic of China. The availability of cheap synthetic camphor (ex turpentine), however, has meant that there is now only modest international demand for the natural form. This, combined with the availability of competitively priced Chinese camphor (US$3.65/kg in early 1994) does not make its production elsewhere particularly attractive.
The use of C. camphora as a source of Ho leaf oil, on the other hand, has expanded in recent years and it is now an important source of natural linalool (which is still preferred over the synthetic form for some fragrance applications). Chinese Ho oil has largely displaced the use of rosewood as a source of natural linalool.
Fractionation of the camphor-free oil obtained from C. camphora provides an oil rich in safrole. This is usually described as Chinese sassafras oil (see SASSAFRAS OIL).
Other Cinnamomum speciesThe ease with which essential oils can be obtained from plant material (and subsequently analyzed in the laboratory) makes them ideal candidates for study as potential cash crops. A screening programme currently underway at the Forest Research Institute of Malaysia focuses on essential oils of indigenous flora and has already examined several Cinnamomum species. Some are considered to have economic potential in providing raw materials for local industry and income to farmers who might grow them. C. mollissimum leaves, for example, contain an oil which is rich in benzyl benzoate and could find application in insecticidal preparations. The trunkwood could possibly be harvested for mucilage on a coppice system (for mosquito coil manufacture), in the same way as C. iners is already being grown in Malaysia.
Cinnamomum species other than C. camphora which contain safrole in their leaves have potential for utilization, providing oil yields and safrole content are high enough to make its recovery worthwhile from an economic point of view.
Leaves of C. tamala (tejpat) are widely used in northern India as a spice but also furnish an essential oil on distillation and this finds some local use. Several chemotypes exist, producing oils rich in cinnamaldehyde or eugenol, but the existence of cheap supplies of these chemicals from other sources (eugenol-rich clove leaf oil from Indonesia, for example) means that C. tamala oil is unlikely to find wider international use.
Similarly, cineole-rich oils from Cinnamomum cannot compete with Eucalyptus oils.
The oils of some other Cinnamomum species are employed in whole form for perfumery use although this is usually in a domestic, rather than international context (e.g. C. porrectum oil, which is rich in neral/geranial, is distilled in the People's Republic of China). Nevertheless, the existence of a local market may be sufficient to encourage small-scale production of such oils. C. osmophloeum is being studied in Taiwan as a possible substitute for cassia oil in the food industry.
ADHIKARY, S.R., TULADHAR, B.S., SHEAK, A., BEEK, T.A.V., POSTHUMUS, M.A. and LELYVELD, G.P. (1992) Investigation of Nepalese essential oils. I. The oil of Cinnamomum glaucescens (sugandha kokila). Journal of Essential Oil Research, 4(2), 151-159.
BRADU, B.L. and SOBTI, S.N. (1988) Cinnamomum tamala in NW Himalayas. Evaluation of various chemical types for perfumery value. Indian Perfumer, 32(4), 334-340.
DUNG, N.X., KHIEN, P.V., CHIEN, H.T. and LECLERCQ, P.A. (1993) The essential oil of Cinnamomum camphora (L.) Sieb. var. linaloolifera from Viet Nam. Journal of Essential Oil Research, 5(4), 451-453.
EOA (1975) Oil of cinnamon bark Ceylon. EOA No. 87. 1 p. Essential Oil Association of USA.
FANG, J.M., CHEN, S.A. and CHENG, Y.S. (1989) Quantitative analysis of the essential oil of Cinnamomum osmophloeum. Journal of Agricultural and Food Chemistry, 37(3), 744-746.
FMA (1992) Cinnamon leaf oil. 5 pp. FMA Monographs, Volume 1. Washington, DC: Fragrance Materials Association of the United States.
GULATI, B.C. (1982) Essential oils of Cinnamomum species. pp. 607-619. In Cultivation and Utilization of Aromatic Plants. Atal, C.K. and Kapur, B.M. (eds). 815 pp. Jammu, India: Regional Research Laboratory.
GURUSINGHE, P. and KIRINDE, S.T.W. (1985) A review of research on spice crops in Sri Lanka. Newsletter of Medicinal and Aromatic Plants, No. 2, 37-44.
ISO (1974) Oil of cassia. International Standard ISO 3216-1974 (E). 2 pp. International Organization for Standardization.
ISO (1977) Oil of cinnamon leaf. International Standard ISO 3524-1977 (E). 2 pp. International Organization for Standardization.
JANTAN, I. and GOH, S.H. (1990) The essential oils of Cinnamomum mollissimum as natural sources of safrole and benzyl benzoate. Journal of Tropical Forest Science, 2(3), 252-259.
JANTAN, I. and GOH, S.H. (1992) Essential oils of Cinnamomum species from peninsular Malaysia. Journal of Essential Oil Research, 4(2), 161-171.
JI, X.D., PU, Q.L., GARRAFFO, H.M. and PANNELL, L.K. (1991) Essential oils of the leaf, bark and branch of Cinnamomum burmannii Blume. Journal of Essential Oil Research, 3(5), 373-375.
LOCKWOOD, G.B. (1979) Major constituents of the essential oils of Cinnamomum cassia Blume growing in Nigeria. Planta Medica, 36(4), 380-381.
LU, B., LI, Y., MAI, L., SUN, B. and ZHU, L. (1986) Chemical constituents of essential oil from Cinnamomum rigidissimum, a new natural resource of safrole. Chemistry and Industry of Forest Products, 6(4), 39-44.
MANZOOR KHUDA, M., FARUQ, M.O., RAHMAN, M., YUSUF, M., WAHAB, M.A. and CHOWDHURY, J. (1984) Studies on the essential oil bearing plants of Bangladesh. I. A preliminary survey of some indigenous varieties. Bangladesh Journal of Scientific and Industrial Research, 19(1/4), 151-169.
MOESTAFA, A. and BADEGES, F. (1986) Distillation of cassia leaf oils (Cinnamomum burmanii, C. zeylanicum and C. cassia) by cohobation method and the identification of oil components. Warta Industri Hasil Pertanian, Indonesia, 3(1), 22-25.
NATH, S.C., HAZARIKA, A.K., BARUAH, R.N., SINGH, R.S. and GHOSH, A.C. (1994) Major components of the leaf oil of Cinnamomum sulphuratum Nees. Journal of Essential Oil Research, 6(1), 77-78.
PURSEGLOVE, J.W., BROWN, E.G., GREEN, C.L. and ROBBINS, S.R.J. (1981) Cinnamon and cassia. pp. 100-173. In Spices, Volume 1. 439 pp. London: Longman.
RAO, E.V.V.B. (1987) Characterization and evaluation of genetic resources in plantation crops. Newsletter of the IBPGR Regional Committee for Southeast Asia, Special Issue, 97-98.
RAO, Y.R., PAUL, S.C. and DUTTA, P.K. (1988) Major constituents of essential oils of Cinnamomum zeylanicum. Indian Perfumer, 32(1), 86-89.
SENANAYAKE, U.M. and WIJESEKERA, R.O.B. (1990) The volatiles of the Cinnamomum species. pp. 103-120. In Proceedings of the 11th International Congress of Essential Oils, Fragrances and Flavours, New Delhi, India, 12-16 November, 1989, Volume 4.
SHI, W.Y., HE, W., WEN, G.Y., GUO, D.X., LONG, G.Y. and LIU, Y.G. (1989) Study on chemical constituents of the essential oil and classification of types from Cinnamomum camphora. Acta Botanica Sinica, 31(3), 209-214.
SMITH, A.E. (1986) International Trade in Cloves, Nutmeg, Mace, Cinnamon, Cassia and their Derivatives. TDRI Report G193. 161 pp. London: Tropical Development and Research Institute [now Chatham: Natural Resources Institute].
WANG, C.L. (1987) The yields and composition analyses of essential oils from planting Cinnamomum osmophloeum Kaueh. Bulletin of the Taiwan Forestry Research Institute, 2(2), 129-144.
WU, H. (1992) A study on the chemotypes of Cinnamomum parthenoxylen (Jack) Nees. Journal of Plant Resources and Environment, China, 1(4), 45-49.
YAACOB, K.B., ZAKARIA, Z. and RAMLI, Z. (1990) Major constituents of Cinnamomum parthenoxylon wood oil. Journal of Essential Oil Research, 2(1), 51.
ZHOU, R. (1983) A new species of safrole-containing plant Cinnamomum petrophilum N. Chao. pp. 102-103. In Proceedings of 9th International Congress of Essential Oils, Singapore, 13-17 March, 1983, Book 1. Singapore: Essential Oils Association of Singapore.
ZHU, L.F., LU, B.Y. and LI, Y.J. (1984) Studies on chemical constituents of essential oil from leaves of jiang-zhang [C. porrectum]. Acta Botanica Sinica, 26(6), 638-643.
Table 1: Exports of cinnamon bark oil from Sri Lanka, and
|Of which to:|
Source: Sri Lankan national statistics
Table 2: Exports of cinnamon leaf oil from Sri Lanka, and
|Of which to:|
Source: Sri Lankan national statistics
Table 3: Imports of cassia oil into the United States, and
|Of which from: China, People's Rep. of||195||286||123||241||na||na||na|
Source: American national statistics
Table 4: Cinnamomum species with
actual or potential use as sources ofchemical isolates
|Species||Plant part||Major oil constituent||percent in oil|
|C. camphora||Wood||Camphor, linalool, safrole or cineole|
|C. camphora var.linaloolifera||Leaves||Linalool||91|
|C. mollissimum||Bark, wood||Safrole||93, 99|
|C. mollissimum||Leaves||Benzyl benzoate||78|
|C. tamala||Leaves||Cinnamaldehyde or eugenol|
Chapter 2 - CINNAMOMUM OILS (INCLUDING CINNAMON AND CASSIA)
"Flavours and fragances of plant origin"
NON-WOOD FOREST PRODUCTS 1
FAO - Food and Agriculture Organization of the United Nations
M-37, ISBN 92-5-103648-9, (c) FAO 1995