Jasmine, which occupies the first place among perfumery flowers, is a product of great value. Its olfactory qualities are due to the essential oils which are located in its flowers. France is an important producer of perfumes, and in the 17th century the centre of the jasmine industry was transferred to Grasse in the Alpes Maritimes.
Jasmine belongs to the family Oleaceae and order Gentianella of the dicotyledons. It is a shrub which has leaves with seven leaflets. It thrives in light, fresh soil and sheltered places. It is a species found in countries with much sunshine and hot dry summers. Almost 100 species are identified. Jasminum nudiflorum, with yellow flowers, is ornamental. Two perfumed species with white flowers are: (1) Jasminum officinale, which came from Iran in 1597 and survives low temperatures, and (2) J. grandiflorum, which has large flowers and came from Nepal in 1624 to the shores of the Mediterranean.
In France, J. grandiflorum is grafted on J. officinale, which is better acclimatized to low temperatures in winter. The thermic and light requirements of J. grandiflorum were determined at the phytotron of Gif-sur-Yvette in France. At a mean temperature of 22 °C, its cultivation is only possible when days are long, while at 12 or 17 °C it appears as a plant which prefers long days.
The produce per ha of J. grandiflorum varies from 5000 to 5500 kg flowers with 8000 to 8500 flowers per kg. The grafted jasmine J. grandiflorum on J. of ficinale produces less flowers per ha (3000 to 3500 kg), but its yield is the same as the ungrafted jasmine and its quality is better. In 1985 at Grasse, the price of the grafted jasmine for the flowers and “absolute” was given as 130F/kg and 40000 F/kg respectively; however, these figures seem to be exaggerated.
Only the flowers are aromatic and used for the extraction of essential oils, which are very volatile and are contained in the cytoplasm of the petal cells. The flowers are treated immediately after harvesting the crop, as their perfume cannot be kept by any distillation or maceration processes known. Two techniques can be used. (1) In the old process the flowers are thrown on a frame with a glass bottom coated with grease, piled in closed rooms. The grease absorbs the perfume and every day the flowers are replaced by new ones to saturate the fat. After 3 months “the jasmine pomatum” is obtained, which, when mixed with alcohol at 95 °C, gives an alcoholic perfumed solution, “the washing”. This concentrated solution under vacuum gives the “potatum absolute”. (2) The present process is quick and in a few minutes, the flowers are treated in a volatile liquid (petroleum ether or n hexane) at 60-80°C, and three fast (10 min) successive extractions are carried out.
The solvent dissolves perfume, wax and colour. These washings are evaporated at normal pressure and the solvent distillation forms a concentrated and perfumed solution which is redistilled under vacuum, and gives a solid and waxy concentrate called “concrete”. The concrete is mixed several times with ethyl alcohol at 95 °C and gives wax, and the aromatic dissolved constituents are separated by filtration. The alcoholic washings are frozen at -18 °C to make the wax particles partially dissolved in alcohol; under vacuum a yellow liquid product is obtained, the “absolute” of commercial interest. Thus 1000 kg of flowers will give 3 kg of “concrete” and 1.5 to 1.7 kg of “absolute”.
In Vitro Cultivation
Biotechnology has greatly helped to mass propagate a number of plant species of commercial interest. Primarily two approaches have been followed: (1) In vitro vegetative multiplication – jasmine plants are contaminated with a number of viruses. First it has been of interest to isolate disease-free plants and then to multiply them with the in vitro microcutting, and (2) callus and cell cultures for the in vitro production of refined essential oil of jasmine.
Essential Oils of Jasmine
In the jasmine flower there is an augmentation of the quantity of essential oils at the time of opening; the relative proportions of the aromatic compounds are greatly modified during the 2 or 3 h which follow the plucking of an opened flower. The increased biosynthesis of the compounds of the essential oil which is found in the petals is provoked by the disruption of correlation between the corolla and rest of the plant. Two hours must lapse between the picking of the flower and its immersion in the extraction solvent if we want to obtain volatile and aromatic products of sufficient strength.
Moreover, the composition of the essential oils shows large differences according to the conditions of temperature and photoperiod. The essential oil of jasmine is very complex and there are more than 100 compounds belonging to different chemical classes, i.e. sugars, alcohols, esters, ketones, phenols etc.. According to Ramachandraiah (1984) the “absolute” of jasmine contains an odiferous and volatile fraction consisting of jasmine, linalol, eugenol, acetate and benzoate of benzyl. Each compound has its odour and participates in the final perfume. A minor volatile and non-odorous fraction representing 20% to 30% of the essential oil with three diterpenic alcohols: phytol, isophytol and geranyl-linalol. Sugars in the essential oils are weak compared with those of other essential oils.
The molecules from which the volatile and non-volatile compounds are synthesized are little known at the moment; whether terpenes are derived from mevalonic acid and the aromatic molecules from skikinic acid and the forms at the precursors of the level of petals is not known.
Jasminum spp. (Jasmine): Conclusions
The best explant for obtaining disease-free plants is the apex grown on MS medium (sometimes diluted) with a mixture of NAA or IBA (1 mg/1) and kin (1 mg/1) or BAP (0.5 to 10 mg/1). Intensive multiplication can be realized from internodes or petiolate leaves on Miller’s medium containing NAA (1 mg/1) and BAP (1 mg/1) at the beginning, and after 30 days transfer to Miller’s medium containing only NAA. For obtaining callus, petals and anthers give good results on Miller’s medium with NAA (1 mg/1) and BAP (1 mg/1).
The jasmine is a floral species which is very much used in perfumery. Its essential oil is very complex, and the “concrete” or “absolute” represent luxury products. For the production of the secondary metabolites by cell suspensions at present no results are available. However, in July 1985, the French firm SANOFI undertook developing biotechnologies in the area of aromas and perfumes, and in Japan, the firm Kanebo made the first experiments in 1985-1986. These interesting perspectives might help to a better understanding of the biosynthesis, and reduce the cost of production and make the product more competitive on the market.
Selections from the book: “Medicinal and Aromatic Plants II”, 1989.