Datura belongs to the family Solanaceae, and is a rich source of numerous alkaloids. Various species range from herbs, shrubs to trees, and they are thus annuals as well as perennials. D. metel with its five varieties originated in India, its fruit is a wart-covered verrucosely hanging capsule. Datura innoxia () originated from Mexico. Safford (1921) and later Danert (1954) dealt with the systematics of these plants. Verzar-Perti and Sarkany (1960) studied the characteristic morphological and anatomical differentiating features, i.e. shape and colour of the seed, and type of trichomes. They can be well differentiated by the corolla as well. Datura metel has five peaks on calices, whereas D. innoxia has ten, which are long and curved like claws. The leaves of D. metel have three lobes, which are almost awnless, whereas the leaves of D. innoxia are very asymmetrical, being heart-shaped and pilous. Various varieties (stramonium L, tatula Torr., inermis Jacq., godronii Danert) of D. stramonium have the shortest growing season.
Datura stramonium and D. innoxia have been extensively tested, especially for their scopolamine and hyoscyamine contents respectively. More than 30 alkaloids have been observed in Datura (), the important ones being the tropanes. Tropane alkaloids are listed as one of the ten substances of plant origin most used in drugs in the USA. Large plantations of Datura have been raised in Brazil, for use in the production of scopolamine and its derivatives. The structure and biosynthetic pathways of tropanes have been extensively studied.
In this post work on in vitro culture of cells and tissues, and the production of tropanes, especially scopolamine and hyoscyamine, in callus cultures is reviewed.
Alkaloid Production in Datura
More than 30 alkaloids have been found in Datura (), the important ones being the tropanes. A few decades ago among various species, Datura stramonium was in the centre of focus, as it is a species supplying hyoscyamine; however, during the last 10-15 years Datura has come to the forefront, primarily as a possible source of scopolamine for the pharmaceutical industry, and interest has increasingly shifted towards D. innoxia. Tropane alkaloids have been used for a variety of pharmaceutical purposes. In addition to other uses, alkaloid extract from flowers of D. innoxia has been employed for anaesthesizing (Shanghai Traditional Medicine Anesthesia Research Coordinating Group 1975).
Datura spp.: Summary and Conclusions
Datura species contain more than 30 alkaloids, and are an important source of tropanes, especially hyoscyamine and scopolamine. In vitro technology for Datura has been well defined for the establishment of tissue cultures, regeneration of plants, production of haploids, somatic hybridization and the induction of mutations in cell cultures. These studies should eventually enable the isolation of high alkaloid-producing cell lines/plants, and their subsequent conservation through cryopreservation.
Of the various factors studied, the root-derived callus cultured in a medium containing kin and 2,4-D and incubated in the dark showed the highest amount of cell biomass and alkaloids. Moreover the incorporation of 214C Na-acetate had a positive effect and caused an appreciable increase in alkaloids. This, if further coupled with the culture of Agrobacterium transformed hairy roots, as in Atropa (), is likely to cause a tremendous increase in the production of alkaloids. Although much needs to be done for the large-scale production of medicinal components, nevertheless these biotechnological approaches have far-reaching implications in the pharmaceutical industry.
Use in traditional medicine:
- in India, datura has long been used for asthma symptoms;
- the Zuni once used datura as an analgesic;
- the Chinese also used it in this manner.
Selections from the book: “Medicinal and Aromatic Plants II”, 1989.