TROPANE ALKALOID PRODUCTION BY DATURA

Atropine and scopolamine, extracted from a variety of plants such as Datura and Scopolla, are among the ten most prescribed medicines derived from plant sources. Increased yields of pharmaceuticals from appropriate plant sources may be effected in a number of ways such as the detailed biochemical analysis Involving the Identification of the rate limiting step(s) in the biosynthesis of the alkaloids followed by manipulation of the plant cell's genome so as to induce constitutive overproducers of alkaloids. Of particular importance to the project was the development of reliable methods for the detection and quantification of the alkaloids extracted from a variety of Datura stramonium tissues. IIPLC and GC methods were developed and were found to be useful for the routine analysis of whole plant extracts. It was difficult to purify tissue culture extracts sufficiently for GC or HPLC analysis and therefore for these types of extracts TLC combined with TLC-scanning was employed. Callus cultures Increased in fresh weight between 300 - 500% over the monthly growth period. Cell culture doubling time was found to be about 3 days. Neither callus nor cell suspension cultures produced appreciable amounts of tropane alkaloids (<lug/gDW). Root cultures were far more productive (about 1000 ug/gDW total alkaloids). It was shown that the Increase in tropane alkaloid biosynthesis in cultured roots ran parallel with root elongation. Possible explanations for this phenomenon have been discussed. Radloactively labelled phenylalanine and ornithine (both precursors to tropane alkaloids) were employed to investigate the biosynthesis of the alkaloids In root and cell cultures. Tn both cell and root cultures precursors were rapidly taken up from the medium and were incorporated into both proteins and alkaloids. Root cultures incorporated vastly more labelled precursors into both proteins and alkaloids than the cell cultures. It was found that crown gall bearing Datura plants possessed an altered tropane alkaloid biosynthetic potential. Differences were found in total alkaloids, distribution of alkaloids and relative proportions of atropine to scopolamine between crown gall bearing and control plants. It Is suggested that plant growth regulators could be the causative agent.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

1988

Author dc:creator

• Walsma, Jan

Licence

• https://dora.dmu.ac.uk/bitstreams/67c6c4dc-d197-4673-84a9-f8958065d869/download