Tropanalkaloide, tropanes, tropeine
Tropane alkaloids are esters of tropanal combined
with various acids. They occur primarily in
nightshades (Solanaceae), especially the psychoactive
ones. The most important psychoactive
tropane alkaloids are atropine, scopolamine, and
hyoscyamine. These substances are "quickly
absorbed through the mucous membranes but
also through the intact skin" (Roth et al. 1994,
944*). For this reason, plant preparations in the
form of ointments with these tropane alkaloids
can induce psychoactive effects (cf. Datura
innoxia, witches' ointments). Atropine, scopolamine,
and hyoscyamine are found in the genera
Atropa, Brugmansia, Datum, Hyoscyamus, Iochroma,
]uanulloa, Mandragora, Solandra, and Scopolia.
The psychoactive tropane alkaloid hyoscyamine
(cf. Hyoscyamus niger) occurs in the following
nightshades in concentrations that appear to make
them useful for psychoactive purposes (Festi 1995,
132 f.*): Anthoceris littorea Labill. (herbage),
Crenedium spinescens Haegi (leaves), Cyphanthera
anthocercidea (Ev. Muel!.) Haegi (leaves),
Mandragora caulescens C.B. Clarke (entire plant;
cf. Mandragora spp.), Physochlaina praealta
(Decne.) Miers (entire plant), and Scopolia lurida
Dunal (roots; cf. Scopolia carniolica). As a plant
dries, the hyoscyamine it contains is usually
transformed into its analog scopolamine. The
profile of effects of hyoscyamine is essentially the
same as that of scopolamine.
Tropanes and cocaine are chemically related
and can under certain conditions elicit similar
pharmacological effects (Sauerwein et al. 1993).
The tropane alkaloid 2-tropanone is a metabolic
product of cocaine. Tropane alkaloids occur in
most if not all Erythroxylum species (AI-Said et al.
1989). The bark of Erythroxylum zambesiacum N.
Robson has been found to contain various
tropanes (Christen et al. 1993). The root bark of
Erythroxylum hypericifolium Lam., a species indigenous
to Mauritius that is used in folk medicine
to treat kidney problems, contains large amounts
of hygrine as well as other tropanes (e.g., cuscohygrine)
(AI-Said et al. 1989). Both hygrine and
cuscohygrine are also found in the leaves and bark
of the two coca species Erythroxylum coca and
Erythroxylum novogranatense (AI-Said et al. 1989,
672). The leaves of the Southeast Asian species
Erythroxylum cuneatum (Wall.) Kurz, which is
used in Malaysia as a tonic, were found to contain as their primary alkaloid (±)-3<X,613-dibenzoyloxytropane;
another major constituent in the leaves is
nicotine. The main alkaloid in the leaves of
another ethnomedicinally useful Southeast Asian
species, Erythroxylum ecarinatum Burck., is tropacacaine.
The root bark of the Australian species
Erythroxylum australe Ev. Muell. also contain
numerous tropanes (meteloidine) (EI-Imam et al.
Tropane alkaloids also appear to be present in
the Proteaceae Family, e.g., in the species Knightia
strobolina (EI-Imam et aL 1988:2182). In Australia,
several members of the genera Hakea and Banksia
are used to produce wine.
The recent discovery of tropane alkaloids
(tropine, tropinone, cuscohygrine, hygrine) in
field bindweed (Convolvulus arvensis 1.; cf. Convolvulus
tricolor) is very interesting; the species
also contains ergot alkaloids (Todd et al. 1995).
Tropane alkaloids have also been found in the
hedge bindweed Calystegia sepium (1.) R. Br. [syn.Convolvulus sepium] (Goldmann et al. 1990).
See also the entries for atropine and scopolamine.
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Alkaloide in pharmakognostisch wichtigen
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Evans. 1993. Recent aspects of tropane alkaloid
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