Apolar Annonaceous acetogenins from the fruit pulp of Annona muricata.

A methylene chloride extract of the pulp of Annona muricata L. was fractionated in search for scarcely functionalized Annonaceous acetogenins (type E). Previously known C-35 and C-37 mono-epoxy unsaturated compounds, epomuricenins-A and -B (1+2) and epomusenins-A and -B (3+4), were obtained. Two new mono-epoxy saturated C-35 representatives, epomurinins-A and -B (5+6) were also isolated.

Biogenetic relationships between Annonaceous acetogenins: squamocin is not a precursor of chamuvarinin based on a semisynthetic study.

In the course of reactivity studies on squamocin (1), a highly cytotoxic acetogenin from the plant family Annonaceae, two diastereomers, 3 and 4, of chamuvarinin (2) were synthesized. Based on this, a plausible relative configuration was proposed for 2, demonstrating the absence of any biogenetic link between 1 and 2. The new analogues 3, 4, and 7 were also tested for their ability to induce apoptosis.

A new adjacent bis-tetrahydrofuran annonaceous acetogenin from the seeds of Uvaria chamae.

A novel acetogenin, joolanin ( 1), along with eight known acetogenins, squamocin ( 2), desacetyluvaricin ( 3), chamuvarinin ( 4), tripoxyrollin ( 5), diepoxyrollin ( 6), dieporeticanin-1 ( 7), dieporeticanin-2 ( 8) and dieporeticenin ( 9) were isolated from the seeds of Uvaria chamae (Annonaceae). Compound 1, the first adjacent bis-tetrahydrofuranic ring acetogenin bearing a ketone group at C-5, shows significant cytotoxicity towards the KB 3 - 1 cell line (IC (50) = 0.4 nM).

Natural cis-solamin is a mixture of two tetra-epimeric diastereoisomers: biosynthetic implications for Annonaceous acetogenins.

The anti-tumour natural product cis-solamin has been shown to occur as a mixture two of tetra-epimeric diastereoisomers 1A and 1B, whereas solamin (6) was isolated as a single diastereoisomer; the biosyntheses of 1A/B and 6 are likely to involve enzyme-mediated cyclohydrations of the bis-epoxide acetogenins anti-diepomuricanin A2 and syn-diepomuricanin A1 respectively, where addition of water occurs regioselectively at either C15 or C20.

Quantification of acetogenins in Annona muricata linked to atypical parkinsonism in guadeloupe.

Atypical parkinsonism in Guadeloupe has been associated with the consumption of fruit and infusions or decoctions prepared from leaves of Annona muricata L. (Annonaceae), which contains annonaceous acetogenins, lipophilic inhibitors of complex I of the mitochondrial respiratory chain. We have determined the concentrations of annonacin, the major acetogenin in A. muricata, in extracts of fruit and leaves by matrix-assisted laser desorption-ionization mass spectrometry. An average fruit is estimated to contain about 15 mg of annonacin, a can of commercial nectar 36 mg, and a cup of infusion or decoction 140 microg. As an indication of its potential toxicity, an adult who consumes one fruit or can of nectar a day is estimated to ingest over 1 year the amount of annonacin that induced brain lesions in rats receiving purified annonacin by intravenous infusion.

Chamuvarinin, an acetogenin bearing a tetrahydropyran ring from the roots of Uvaria chamae.

A new cytotoxic acetogenin, chamuvarinin (1), containing a tetrahydropyran ring with an adjacent bis-tetrahydrofuran ring, which corresponds to a novel carbon skeleton in this series, was isolated from the roots of Uvaria chamae, together with the previously reported acetogenins squamocin (2), desacetyluvaricin (3), and neoannonin (4). The structure determination of chamuvarinin (1) was based on extensive NMR studies and high-resolution mass spectral measurements. This new compound shows significant cytotoxicity toward the KB 3-1 cell line (IC50 = 8 x 10(-10) M). In addition, a biosynthetic relationship between 1 and 2 is briefly discussed.

Cis-bullatencin, a linear acetogenin from roots of Uvaria chamae.

A novel acetogenin, cis-bullatencin, was isolated by successive chromatography of a cyclohexane extract of Uvaria chamae P. Beauv. roots. The structure was elucidated by a combination of chemical and spectroscopic methods (NMR, MS). Eight known mono-THF acetogenins--bullatencin, annotemoyin-1, solamin, uvariamicin-I, -II, -III, cis-reticulatacin and cis-uvariamicin-I--were also obtained.

Acaricidal activity of tonka bean extracts. Synthesis and structure-activity relationships of bioactive derivatives.

The acaricidal effects of tonka bean, Dipterix odorata, extracts were investigated on Dermatophagoides pteronyssinus, the European house dust mite, and compared with benzyl benzoate as a standard acaricidal compound. A cyclohexane extract was the most effective, with an EC(50) = 0.075 g/m(2) after a 24 h period, as compared with benzyl benzoate (0.025 g/m(2)). Bioassay-guided fractionation of this extract led to the isolation of coumarin (1). Pharmacomodulation of this compound led us to test 20 analogues (2-21), which were either synthesized or purchased.

Annonacin, a lipophilic inhibitor of mitochondrial complex I, induces nigral and striatal neurodegeneration in rats: possible relevance for atypical parkinsonism in Guadeloupe.

In Guadeloupe, epidemiological data have linked atypical parkinsonism with fruit and herbal teas from plants of the Annonaceae family, particularly Annona muricata. These plants contain a class of powerful, lipophilic complex I inhibitors, the annonaceous acetogenins. To determine the neurotoxic potential of these substances, we administered annonacin, the major acetogenin of A. muricata, to rats intravenously with Azlet osmotic minipumps (3.8 and 7.6 mg per kg per day for 28 days). Annonacin inhibited complex I in brain homogenates in a concentration-dependent manner, and, when administered systemically, entered the brain parenchyma, where it was detected by matrix-associated laser desorption ionization-time of flight mass spectrometry, and decreased brain ATP levels by 44%. In the absence of evident systemic toxicity, we observed neuropathological abnormalities in the basal ganglia and brainstem nuclei. Stereological cell counts showed significant loss of dopaminergic neurones in the substantia nigra (-31.7%), and cholinergic (-37.9%) and dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32)-immunoreactive GABAergic neurones (-39.3%) in the striatum, accompanied by a significant increase in the number of astrocytes (35.4%) and microglial cells (73.4%). The distribution of the lesions was similar to that in patients with atypical parkinsonism. These data are compatible with the theory that annonaceous acetogenins, such as annonacin, might be implicated in the aetiology of Guadeloupean parkinsonism and support the hypothesis that some forms of parkinsonism might be induced by environmental toxins.