J.W. Fairbairn

Alkaloidal storage, metabolism and translocation in the vesicles of Papaver somniferum latex

Abstract After centrifuging stem and capsule latex of Papaver somniferum at 1000 g , 95–99% of the alkaloids were found in the pellet, which consists m

Alkaloid biosynthesis and metabolism in an organelle fraction in Papaver somniferum

Abstract The pellet produced by centrifuging suitably diluted latex at 1000–3000 g has been shown capable of synthesizing morphine from dihydroxyphenylalanine in vitro and preliminary studies indicate that a lutoid-like organelle is involved in this synthesis. Evidence is also produced to show that the further metabolism of morphine (described earlier 1 ) takes place in the stem latex and its 3000 g fraction rather than in the capsule latex.

The alkaloids ofPapaver somniferum L.—VI.: “Bound” morphine and seed development

Abstract Vigorous acid hydrolysis or pepsin digestion of ground poppy seeds led to the production of alkaloid-like substances including codeine. Fermentation of ground seeds or germination of whole seeds for 1 to 2 days also led to the production of similar compounds as well as papaverine. Radioactive morphine was fed to the latex of the capsule and the seeds collected later were germinated in similar conditions and the alkaloid-like substances shown to be radioactive. Furthermore the ovules were shown to contain radioactive alkaloid-like substances (without degradative treatment) as well as radioactive non-alkaloidal compounds similar to those already reported. It is suggested that morphine is rapidly metabolised in the latex into a series of compounds some of which are alkaloid-like and others non-alkaloidal, ethanol insoluble, “bound” forms. The bound forms are stored in the seeds and broken down into smaller alkaloid-like substances during germination. An attempt was made to produce seeds deficient in these compounds by depriving the capsule of much of its latex at a critical stage in development. The seeds produced showed remarkable differences from controls; their germination rate and root hair and chlorophyll production were significantly reduced, thus indicating that the latex contents are essential to the production of viable seeds. The possible pharmacological effect of bound forms of alkaloids in poppy seeds is also discussed.

The alkaloids of Papaver somniferum L.—VII : Biosynthetic activity of the isolated latex

Abstract Earlier work on the biosynthesis of alkaloids by poppy latex has been criticised on the grounds that the final products owed their radioactivity to contamination with the precursor. In the present work, not only has the extent of contamination been studied, but radioactive 3,4-dihydroxyphenylalanine has been found to be much more efficiently incorporated into the alkaloids than is tyrosine or glucose. It was therefore possible to isolate substantial quantities of radioactive morphine whose purity was established by radioactive measurements after re-crystallisation, formation of diacetyl derivative and picrate, and by radioisotope dilution techniques. Four other alkaloids were also shown to be radioactive though not with such certainty. The fact that such sophisticated syntheses take place in isolated latex indicates that the latter is cytoplasmic with adequate organelle activity.

Biosynthetic and metabolic activities of some organelles in Papaver somniferum latex

Abstract The biosynthesis of the five major alkaloids of the opium poppy ( Papaver somniferum L. from radioactive dihydroxyphenylalanine has been studied in the 1000 g , 10 000 g , 100 000 g pellets and the 100 000 g supernatant fractions of the capsule latex. A normal poppy variety as well as one which produces only traces of alkaloids were used. Definite evidence of biosynthesis was obtained for both varieties but only in the 1 000 g pellet (as previously reported . None was found in the other fractions although electron microscopy showed that organelles, including vesicles, were present. The amounts of alkaloid biosynthesized however were very small relative to the amounts involved in the rapid changes already reported for the developing capsules. In contrast, all fractions of the latex were able to metabolize T-morphine in vitro , with the 100 000 g supernatant showing the highest activity and the amounts involved were also consistent with the changes found in the living plant.

The biosynthesis and metabolism of anthraquinones in Rumex obtusifolius

Abstract Radioactive acetate was fed to Rumex obtusifolius plants and after 7 days aloe-emodin, chrysophanol and emodin were isolated and found to be radioactive. Each was degraded to phthalic acids and the proportion of radioactivity present in the acids shown to be consistent with the acetate-malonate route earlier established for a related species of Rumex . The subsequent fate of the anthraquinones was studied by observing the changes in glycosidic and free anthraquinones in developing fruits and by feeding radioactive aglycones to the inflorescences. The results indicate a rapid utilization of the anthraquinones in the early stages of fruit formation, followed by a more gradual use, and coincide well with similar work on the developing fruits of Cassia acutifolia .

Bound forms of alkaloids in Papaver somniferum and P. Bracteatum

Abstract The polysaccharide fraction of the pericarp and seed of Papaver somniferum were shown to contain bound forms of morphine which were derived from radioactive morphine fed to living plants. Bound forms of codeine, thebaine and some unidentified alkaloid-like compounds were also detected in the pericarp and bound thebaine occurred in the pericarp of Papaver bracteatum . The complexity and molecular weight of the bound alkaloids seemed to increase during ripening, and it is suggested that these substances represent transitional forms in the metabolism and transiocation of morphine from latex to seed.

In vitro conversion of morphine to its N-oxide in Papaver somniferum latex

Abstract Radio active morphine ( 14 C- and 3 H-labelled) was fed in vitro to freshly collected samples of capsules and stem latex of Papaver somniferum and it was shown that some of it was converted to radioactive N -oxide. Although metabolic activity and variation between samples of latex collected at different times were much less marked than those previously found using in vivo methods, the results do confirm that the isolated latex is a metabolically viable tissue.

The alkaloids of hemlock (Conium maculatum L.)—III : The presence of bound forms in the plant

Abstract Evidence is produced to indicate that the major alkaloids of hemlock, coniine and γ-coniceine, occur as bound forms as well as the normal free salts. These bound forms vary from ethanol-soluble substances which readily break down into coniine or γ-coniceine, to larger, more resistant, water-soluble complexes which on vigorous treatment break down to alkaloid-like compounds. The quantities vary during fruit development and it is suggested that the alkaloids are built up into a series of compounds of increasing complexity which may play an important part in the metabolism of the fruit.

Meconic acid as a chemotaxonomic marker in the papaveraceae

Abstract Of 48 species of Papaveraceae examined representing 12 genera, 24 were shown to contain meconic acid and of these, 21 were Papaver species. Meconopsis cambrica was also found to contain meconic acid, in contrast to other species of Meconopsis examined. One recent rearrangement of the Papaveraceae includes a grouping of Papaver, Roemeria and Stylomecon together with M. cambrica and our further discovery of meconic acid in two Roemaria species examined leads to the conclusion that meconic acid may be a distinctive taxonomic feature of this new grouping. Some attempt has also been made to correlate meconic acid occurrence with that of certain types of alkaloids, and of chelidonic acid.