acetogenins and chamuvarinin

The need for new treatments for the neglected tropical diseases African sleeping sickness, Chagas disease and Leishmaniasis remains urgent with the diseases widespread in tropical regions, affecting the world's very poorest. We have previously reported bis-tetrahydropyran 1,4-triazole analogues designed as mimics of the annonaceous acetogenin natural product chamuvarinin, which maintained trypanocidal activity. Building upon these studies, we here report related triazole compounds with pendant heterocycles, mimicking the original butenolide of the natural product. Analogues were active against T. brucei, with a nitrofuran compound displaying nanomolar trypanocidal activity. Several analogues also showed strong activity against T. cruzi and L. major. Importantly, select compounds gave excellent selectivity over mammalian cells with a furan-based analogue highly selective while remaining active against all three cell lines, thus representing a potential lead for a new broad spectrum kinetoplastid inhibitor.

Topics: Acetogenins; Cell Survival; Drug Design; Furans; HeLa Cells; Humans; Leishmania major; Structure-Activity Relationship; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

Neglected tropical diseases remain a serious global health concern. Here, a series of novel bis-tetrahydropyran 1,4-triazole analogues based on the framework of chamuvarinin, a polyketide natural product isolated from the annonaceae plant species are detailed. The analogues synthesized display low micromolar trypanocidal activities towards both bloodstream and insect forms of Trypanosoma brucei, the causative agent of African sleeping sickness, also known as Human African Trypanosomiasis (HAT). A divergent synthetic strategy was adopted for the synthesis of the key tetrahydropyran intermediates to enable rapid access to diastereochemical variation either side of the 1,4-triazole core. The resulting diastereomeric analogues displayed varying degrees of trypanocidal activity and selectivity in structure-activity relationship studies. Together, the biological potency and calculated lipophilicity values indicate that while there is room for improvement, these derivatives may represent a promising novel class of anti-HAT agents.

Topics: Acetogenins; HeLa Cells; Humans; Models, Molecular; Stereoisomerism; Structure-Activity Relationship; Triazoles; Trypanocidal Agents; Trypanosoma brucei brucei

A highly stereocontrolled synthesis of (+)-chamuvarinin has been completed in 1.5% overall yield over 20 steps. The key fragment coupling reactions were the addition of alkyne 8 to aldehyde 7 (under Felkin-Anh control), followed by the two step activation/cyclization to close the C20-C23 2,5-cis-substituted tetrahydrofuran ring and a Julia-Kocienski olefination at C8-C9 to introduce the terminal butenolide. The inherent flexibility of our coupling strategy led to a streamlined synthesis with 17 steps in the longest sequence (2.2% overall yield), in which the key bond couplings are reversed. In addition, a series of structural analogues of chamuvarinin have been prepared and screened for activity against HeLa cancer cell lines and both the bloodstream and insect forms of Trypanosoma brucei, the parasitic agent responsible for African sleeping sickness.

Topics: Acetogenins; Aldehydes; Cell Survival; Cyclization; HeLa Cells; Humans; Molecular Structure; Stereoisomerism; Trypanosoma brucei brucei

A stereocontrolled total synthesis of (+)-chamuvarinin, isolated from the root extract of Uvaria Chamae, utilizes a convergent modular strategy to construct the adjacently linked C15-C28 ether array, followed by a late-stage Julia-Kocienski olefination to append the butenolide motif. This constitutes the first total synthesis of (+)-chamuvarinin, defining the relative and absolute configuration of this unique annonaceous acetogenin.

Topics: Acetogenins; Molecular Structure; Plant Roots; Stereoisomerism; Uvaria

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.

Topics: Acetogenins; Annonaceae; Antineoplastic Agents, Phytogenic; Apoptosis; Fatty Alcohols; Furans; Lactones; Molecular Structure; Plants, Medicinal; Pyrans

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.

Topics: Acetogenins; Antineoplastic Agents, Phytogenic; Drug Screening Assays, Antitumor; Furans; Humans; Inhibitory Concentration 50; KB Cells; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Plant Roots; Plants, Medicinal; Pyrans; Senegal; Structure-Activity Relationship; Tumor Cells, Cultured; Uvaria