Tuberose: for ornamental use and in essential oils

Among the wide diversity of native plants that Mexico has provided to ornamental horticulture, the tuberose stands out for its beauty, fragrance, and ease of propagation.

Familiar to agaves, the tuberose belongs to the genus Polianthes, which includes a few wild herbaceous species, all endemic to Mexico and with restricted distribution. They can be found in small populations or as isolated individuals in forest and grassland areas where, due to the damage to these habitats by human activity, some of these species have irrigated status.

Since pre-Hispanic times, the tuberose was already highly appreciated by the Aztecs where it was grown for ceremonial, ornamental, and medicinal purposes. The Aztecs called it "Omixochitl" in Nahuatl, a name that referred to its white flowers (since the Spanish translation is "bone flower"); however, because the bulbs of this species along with other wild species of the genus present some soapy substances, it was also called "Amole" (soap) because of the use they gave it as a substitute for soap, although this last name also includes another bulbous species related to the genus Manfreda and Prochnianthes. The Aztecs also recognized in the tuberose antiseptic, analgesic, anti-inflammatory, and antispasmodic activities.

After the Spanish conquest, the tuberose was brought to Europe from where it was distributed to different parts of the world from the 16th century onwards. Nowadays it is one of the most popular cut flowers in tropical and subtropical climates. In Mexico, the use of the tuberose is as a cut flower, is produced mainly in the states of Morelos, Puebla, and the State of Mexico, where it is grown in the open and handled in an unscrupulous way during its harvest and transport because its flower stems are incredibly resistant to handling and long vase life in relation to other cut flowers.

Under proper management and climatic conditions, tuberose grows efficiently in the open, and only in regions with extreme winter can the bulbs go dormant and reactivate in early spring. If the winter is mild, the plants can produce flower stems year-round, with an abundant flow of flowers in the summer, lowering the production and quality of flowers in the winter and remaining so for several years. However, because it is attacked by a picudo (the same insect that attacks its more popular relative Agave tequilana, read more about picudos) that also interacts with some diseases, plantations are maintained until management costs are economically sustainable.

Due to the high content of essential oils in its flowers, tuberose is also used in the perfume industry, in countries like France and India it is an industry of equal or even greater magnitude than ornamental use. The flowers of the tuberose present high contents of methyl benzoate, methyl salicylate, methyl isoeugenol, and benzyl benzoate, as well as some terpenes such as 1,8-cineole, farnesene, and germacrene, these components, make the essential oil of tuberose one of the most valuable in the perfumery, many of the current luxury perfumes count as the main ingredient or as part of its notes essential oil of tuberose. Another use for tuberose essential oil is in aromatherapy; however, because of the high cost of the essential oil, it is restrictive. Some properties that have been attributed to the fragrances of nardo are relaxing effects on the brain, nerves, and muscles; antidepressant, aphrodisiac, and even narcotic.

In addition to being the organ used for the propagation of the tuberose, tuberose bulbs (corms) also contain compounds of interest mainly saponins, such as thioguanine and hecogenin which have been shown to have a molluscicidal effect (pesticides used to control mollusks, for example, snails), as well as spirostanol and other sapogenins which have been shown to have an effect on human diseases such as leukemia and oral cancer. A polysaccharide that can be used as a sanitizer is also reported to be obtained from tissue culture.

In this way, after more than 500 years of being cultivated by the Aztecs, the tuberose has an important place in world floriculture, it presents important chemical qualities that are already being used in the perfumery, but it can also be considered an important source of other compounds with potential that needs to be further studied.

Source: CIATEJ