Eustoma grandiflorum Shinn (Texas Bluebell)

Eustoma belongs to the family Gentianaceae. The taxonomy of this genus has been studied by Shinners (), who distinguished the species Eustoma grandiflorum Shinn. and Eustoma exaltatum (L.) Salisb. Taking into account morphological features of the leaves and growth, the author proposed distinguishing another species – Eustoma barkleyi Standley. Table List of synonyms used in the terminology of the genus Eustoma will help obtain a clear picture of the synonyms used in the nomenclature of the genus Eustoma.

Table List of synonyms used in the terminology of the genus Eustoma. ()

The most popular species, Eustoma grandiflorum, grows in its natural state in the USA, from Nebraska to Louisiana, and Mexico. It is known by its local names of the Texas bluebell, the lira de San Pedro, or the prairie gentian. It is an annual or perennial plant, depending on its range. The species comprises several forms (f.) ():

f. grandiflorum – blue-purple flowers with a dark center,

f. fisheri – white flowers,

f. bicolor – white flowers with purple streaks,

f. roseum – pink flowers,

f. flaviflorum- yellow flowers.

Importance of Eustoma grandiflorum

Thus far, Eustoma grandiflorum is primarily of commercial importance. Because of the colorful flowers (20 to 40 on each plant, blooming for some 25 days), this species is grown for cut and pot flowers (). This ornamental plant was introduced more than 50 years ago in Japan, where over 15 varieties can be found, and has spread under the name of torukogikyo ().

Most popular are three Japanese cultivars: with blue flowers – Murasaki no Mine; pink flowers – Sakuro no Mine (known as Momo no Mine); white flowers -Kiri no Mine (known as Yuki no Mine). Their cultivation has shown that the white variety requires a higher concentration of growth regulators than the other two. Eustoma grandiflorum has also aroused interest in Polish gardening ().

In Eustoma grandiflorum such secondary metabolites have been found as xanthones, secoiridoids, and flavonoids. These groups of compounds have also been reported to occur in many genera of the family Gentianaceae, e.g., Blackstonia, Canscora, Coutoubea, Centaurium, Gentiana, Helenia, and Swertia. Apart from being systematic markers, these compounds are of great significance due to their biological activity. Numerous species of the mentioned genera supply a number of countries with raw materials for phytotherapy (). E. grandiflorum has a set of pharmacologically active compounds and therefore can be a valuable therapeutic material, or can serve as a source of pure chemical compounds, apart from its strictly ornamental uses.

Apart from its ornamental properties, Eustoma grandiflorum can be of medicinal significance due to the occurrence of such biologically active compounds as secoiridoids, flavonoids, and xanthones. Interest is focused on secoiridoids as bitter compounds affecting the immunological system (). In this group of compounds, gentiopicroside metabolites were studied for their anticancer and bacteriostatic activity (). Attention is also paid to the pharmacological properties of flavonoids () as well as the antiamoebic properties of xanthones ().

The propagation of Eustoma grandiflorum by in vitro cultures opens up wide possibilities for horticulture and for obtaining the material for compound isolation. Plants regenerated in vitro can synthesize secoiridoids and flavonoids even in their callus tissues.

Selections from the book: “Medicinal and Aromatic Plants V”, 1993.