Solanaceae alkaloids

In grafting experiments involving Nicotiana rustica or N. tabacum and a nicotine-free stock like potato (Meyer and Schmidt, 1910) or tomato (Schmuk et aL, 1941a,b Dawson, 1944, 1951 Lashuk, 1948 Ill in, 1948, 1955 Solt and Dawson, 1958 Mothes, 1955, 1969 Kuzdowicz, 1955), it was found that the scions were alkaloid-free or had a considerably reduced alkaloid content (Dawson, 1942) (Table 4.2). (The reader is referred to articles by Dawson (1948) and Dawson and Osdene (1972) for more infor- 

Several authors have studied nicotine production (i.e., biosynthesis) in callus tissue cultures (Speake et al., 1964 Benveniste et al., 1966 Furuya et al.y 1966, 1971 Tabata et aL, 1968, 1971 Shiio and Ohta, 1973 and Heinze, 1975). The biosynthesis of nicotine is dependent upon the formation of organized tissue within the callus. Nodule-like structures similar to roots were observed in our laboratories using tobacco variety Maryland-872, which produces 96% of its alkaloids as nicotine. Shoot formation stimulated nicotine production in the callus, and nicotine may have been transported from the callus to the shoot. Nicotine production and tissue differentiation were dependent upon concentrations and types of growth regulators in the culture medium (Tables 4.3 and 4.4). The vegetative buds and leaves (shoots) contained about live times as much nicotine as callus without buds or leaves, which is in agreement with the results of Tabata et al (1968). 

Similar results have been published for other Solanaceae alkaloids, namely, those of the tropane group. Heine (1942) grafted Datura scions upon Nicotiana rustica and found that nicotine accumulated instead of tropane alkaloids. This finding was confirmed by Hills et al, (1946) with Nicotiana-Duboisia grafts. The tobacco scion on Duboisia root was found to accumulate tropane alkaloids. Surprisingly, the tobacco scion accumulated both hyoscine and the unesterified tropine. In all grafts between plants 

Histologic peculiarities of the Solanaceae make it relatively easy to combine different species of these plants in a graft of chimera. The Solanaceae were a good choice for this type of experiments because some species of this plant family contain plants which produce different types of alkaloids and still others are alkaloid-free. Thus the Nicotiana and Datura genera are capable of producing alkaloids derived from ornithine, while 

Leaves that were removed from the callus (above) 335 20 

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The solanaceae alkaloids and other other sources of antimuscarinics affect the CNS. They can produce hallucinations in addition to their effects on the peripheral nervous system. Witchcraft of the Middle Ages produced mixtures of plants - deadly nightshade, monkshood, and hemlock among them - as "flying ointments". The combined toxins disturbed the rhythm of the heart and led to delirium which could create a sensation of rising and falling, that is, flying. 

Cuscohygrine was isolated in 1889 from the leaves of Erythroxylon coca and the structure established by Liebermann. Later, it was reported to be a minor component of many other Solanaceae alkaloids.31 Like related alkaloids, cuscohygrine epimerizes readily so that it has never been obtained as an optically active material. In contrast, naturally occurring dihydrocuscohygrine isolated by Turner in 198132 occurs in different Solanaceae species as the (-)-enantiomer. 

The clinically used Solanaceae-alkaloids hyoscyamine, atropine and scopolamine are esters of tropic acid. Since tropic acid has an asymmetric C-atom, these alkaloids occur in L-, D- and DL-forms, the L-form of which is the also most pharmacologically active. 

A large plant family may produce several groups of structurally diverse alkaloids. One example is the plant family the Solanaceae. Therefore, if a classification based on a Solanaceae alkaloid is used, solanine, isolated from the bud of potato Solamm tuberosum), the tropane alkaloids, are grouped... 

Figure 4.1b. Grafting experiments with Solanaceae. Alkaloid-rich plants grafted on alkaloid-poor roots a—Nicotiana tabacum on Solanum tuberosum b—Lycopersicon esculentum on S. tuberosum (control) c—Datura stramonium on Cyphomandra betacea d—Nicotiana glauca on L. esculentum. Grafts a, b, c, were alkaloid-free graft d produced only anabasine.

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