In the French West Indies there is an abnormally high frequency of levodopa-resistant parkinsonism, suggested to be caused by consumption of fruit and infusions of tropical plants, especially Annona muricata (corossol, soursop). To determine whether toxic substances from this plant can cause the neuronal degeneration or dysfunction underlying the syndrome, we exposed mesencephalic dopaminergic neurons in culture to the total extract (totum) of alkaloids from Annona muricata root bark and to two of the most abundant subfractions, coreximine and reticuline. After 24 hours, 50% of dopaminergic neurons degenerated with 18 microg/ml totum, 4.3 microg/ml (13 microM) coreximine, or 100 microg/ml (304 microM) reticuline. The effects of the alkaloid totum were not restricted to the population of dopaminergic cells since GABAergic neurons were also affected by the treatment. Nuclei in dying neurons showed DNA condensation or fragmentation, suggesting that neuronal death occurred by apoptosis. Cell death was not excitotoxic and did not require toxin uptake by the dopamine transporter. Neurodegeneration was attenuated by increasing the concentration of glucose in the culture medium, which also reduced the effect of the dopaminergic neurotoxin MPP+, a mitochondrial respiratory chain inhibitor. Toxin withdrawal after short-term exposure arrested cell death. Acute treatment with totum, coreximine, or reticuline reversibly inhibited dopamine uptake by a mechanism that was distinct from that causing neuronal death. GABA uptake was not reduced under the same conditions. This study suggests that alkaloids from A. muricata can modulate the function and the survival of dopaminergic nerve cells in vitro. It is therefore conceivable that repeated consumption could cause the neuronal dysfunction and degeneration underlying the West Indian parkinsonian syndrome.

Eight chemically defined, naturally occurring compounds were extracted from the tropical flora of the Caribbean island of Guadeloupe: pilocarpine, an alkaloid from Pilocarpus racemosus ; heraclenol and isomeranzin, coumarins from Triphasia trifolia; lochnerin, an indole alkaloid from Rauwolfia biauriculata; ibogaine and voacangine, indole alkaloids from Tabernaemontana citrifolia ; texalin, an oxazole from Amyris elemifera; and canellal, a sesquiterpene dialdehyde from Canella winterana. An essential oil fraction from Canella winterana was also tested. The antimycobacterial activity of these substances was tested against Mycobacterium tuberculosis, M. avium and M. kansasii using the Middlebrook 7H11 agar medium, the Bactec 460-TB radiometric methodology, and determination of bacterial viable counts. Three compounds, namely ibogaine, voacangine and texalin, showed antimycobacterial activity. Investigations on the structure-modification and structure-activity relationships of these compounds may help determine new targets for future drug development. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.

In Guadeloupe, three kinds of plants that have the botanical name of Pimenta racemosa var. racemosa (P.Miller) J. W. Moore (Myrtaceae) can be found. They differ from one another by the smell of their leaves: smells similar to those of clove, lemon and anise. An analysis of the essential oils of each type shows differences concerning their physical characteristics and their chemical compositions ; in two chemotypes, major amounts of phenolic ethers (eugenol, chavicol, estragole, methyleugenol) were observed whereas the third one mainly contains acyclic oxygenated monoterpenes such as geranial and neral

Along with the known alkaloid, O-methylhalfordinol, five known coumarins have been isolated from the leaves oiTriphasia trifolia. The structure of a sixth coumarin, the novel substance 3',-dehydroxy-3''-chlorotriphasiol [10] was determined by the interpretation of spectroscopic parameters.La famille des Rutacées est bien représentée dans les regions tropicales et compre de nombreuses especes utilisées en médecine traditionnelle. Dans les Antilles frangaises, des infusions de feuilles de Triphasia trifolia (Burm. f.) P. Wilson, ou citronnelle á épines, sont utilisées comme vermicide.

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