Browsing by Autor "Sophie Manner"

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Cytotoxicity of New Damsin Derivatives in Breast Cancer Cells
(Lund University, 2019) Maribel Lozano; Wendy Soria; Giovanna R. Almanza; Sophie Manner; Stina Oredsson; Juan R V Villagomez; Olov Sterner
Abstract As a follow-up of a previous investigation in which semisynthetic damsin derivatives were shown to possess up to 10 times higher cytotoxicity in JIMT-1 breast cancer cells compared to normal breast epithelial MCF-10A cells, a range of new derivatives were prepared and assayed toward the same cells. Damsin, a natural plant metabolite containing a??-methylene-?-lactone (or 3-methylenedihydrofuran-2(3H)-one) moiety, was modified in position 3 by Claisen-Schmidt condensations with aromatic aldehydes, mainly mono- or disubstituted benzaldehydes, without affecting the α-methylene-γ-lactone function. This lactone ring is a Michael acceptor that is known to affect biological processes such as cell proliferation, death/apoptosis, and cell migration, by interfering with nucleophilic sites in cell signalling pathways. However, although Michael acceptors are reactive, the Michael addition is reversible and it can be assumed that also other parts of the molecules will moderate the binding to and the release from any given nucleophilic site in a protein, and thereby moderate a specific biological activity. In this investigation, the cytotoxicity of 20 α-methylene-γ-lactones towards normal breast epithelial MCF-10A cells as well as breast cancer JIMT-1 cells is compared, by determining the inhibitory concentration 50 (IC50) from dose response curves. The IC50 values in the two cell lines were found to depend on the overall structure of the assayed compounds, although less in this subset of compounds compared to a previous investigation. Structure-activity relationships that may explain the observed differences in potency and selectivity are discussed.
SAR:s for the Antiparasitic Plant Metabolite Pulchrol. 1. The Benzyl Alcohol Functionality
(Multidisciplinary Digital Publishing Institute, 2020) Paola Terrazas; Efraín Salamanca; Marcelo Dávila; Sophie Manner; Alberto Giménez; Olov Sterner
Pulchrol (1) is a natural benzochromene isolated from the roots of Bourreria pulchra, shown to possess potent antiparasitic activity towards both Leishmania and Trypanozoma species. As it is not understood which molecular features of 1 are important for the antiparasitic activity, several analogues were synthesized and assayed. The ultimate goal is to understand the structure-activity relationships (SAR:s) and create a QSAR model that can be used for the development of clinically useful antiparasitic agents. In this study, we have synthesized 25 2-methoxy-6,6-dimethyl-6H-benzo[c]chromen analogues of 1 and its co-metabolite pulchral (5a), by semi-synthetic procedures starting from the natural product pulchrol (1) itself. All 27 compounds, including the two natural products 1 and 5a, were subsequently assayed in vitro for antiparasitic activity against Trypanozoma cruzi, Leishmania brasiliensis and Leishmania amazoniensis. In addition, the cytotoxicity in RAW cells was assayed, and a selectivity index (SI) for each compound and each parasite was calculated. Several compounds are more potent or equi-potent compared with the positive controls Benznidazole (Trypanozoma) and Miltefosine (Leishmania). The compounds with the highest potencies as well as SI-values are esters of 1 with various carboxylic acids.
SARs for the Antiparasitic Plant Metabolite Pulchrol. 3. Combinations of New Substituents in A/B-Rings and A/C-Rings
(Multidisciplinary Digital Publishing Institute, 2021) Paola Terrazas; Efraín Salamanca; Marcelo Dávila; Sophie Manner; Alberto Giménez; Olov Sterner
The natural products pulchrol and pulchral, isolated from the roots of the Mexican plant Bourreria pulchra, have previously been shown to possess antiparasitic activity towards Trypanosoma cruzi, Leishmania braziliensis and L. amazonensis, which are protozoa responsible for Chagas disease and leishmaniasis. These infections have been classified as neglected diseases, and still require the development of safer and more efficient alternatives to their current treatments. Recent SARs studies, based on the pulchrol scaffold, showed which effects exchanges of its substituents have on the antileishmanial and antitrypanosomal activity. Many of the analogues prepared were shown to be more potent than pulchrol and the current drugs used to treat leishmaniasis and Chagas disease (miltefosine and benznidazole, respectively), in vitro. Moreover, indications of some of the possible interactions that may take place in the binding sites were also identified. In this study, 12 analogues with modifications at two or three different positions in two of the three rings were prepared by synthetic and semi-synthetic procedures. The molecules were assayed in vitro towards T. cruzi epimastigotes, L. braziliensis promastigotes, and L. amazonensis promastigotes. Some compounds had higher antiparasitic activity than the parental compound pulchrol, and in some cases even benznidazole and miltefosine. The best combinations in this subset are with carbonyl functionalities in the A-ring and isopropyl groups in the C-ring, as well as with alkyl substituents in both the A- and C-rings combined with a hydroxyl group in position 1 (C-ring). The latter corresponds to cannabinol, which indeed was shown to be potent towards all the parasites.
SARs for the Antiparasitic Plant Metabolite Pulchrol. Part 2: B- and C-Ring Substituents
(Multidisciplinary Digital Publishing Institute, 2020) Paola Terrazas; Sophie Manner; Olov Sterner; Marcelo Dávila; Alberto Giménez; Efraín Salamanca
Neglected tropical diseases affect most of the underprivileged populations in tropical countries. Among these are chagas and leishmaniasis, present mainly in South and Central America, Africa and East Asia. Current treatments are long and have severe adverse effects, therefore there is a strong need to develop alternatives. In this study, we base our research on the plant metabolite pulchrol, a natural benzochromene which has been shown to possess antiparasitic activity against Trypanosoma and Leishmania species. In a recent study, we investigated how changes in the benzyl alcohol functionality affected the antiparasitic activity, but the importance of B- and C-ring substituents is not understood. Fifteen derivatives of pulchrol with different substituents in positions 1, 2, 3, and 6 while leaving the A-ring intact, were therefore prepared by total synthesis, assayed, and compared with pulchrol and positive controls. The generated series and parental molecule were tested in vitro for antiparasitic activity against Trypanosoma cruzi, Leishmania braziliensis, and L. amazonensis, and cytotoxicity using RAW cells. Substantial differences in the activity of the compounds synthesized were observed, of which some were more potent towards Trypanosoma cruzi than the positive control benznidazole. A general tendency is that alkyl substituents improve the potency, especially when positioned on C-2.
Selective Cytotoxicity of Dams in Derivatives in Breast Cancer Cells
(2019) Maribel Lozano; Maribel Lozano; Wendy Soria; Wendy Soria; Giovanna R. Almanza; Sophie Manner; Stina Oredsson; Rodrigo Villagomez; Olov Sterner
Cancer is the leading cause of death worldwide, and there is a constant need for new treatment strategies. Sesquiterpene lactones containing a 3-methylenedihydrofuran-2(3H)-one (or a-methylene-g-lactone) moiety, for example damsin (1), are Michael acceptors that affect biological processes such as cell proliferation, death/apoptosis, and cell migration, by interfering with cell signalling pathways. Although the reactivity of the α-methylene-γ-lactone moiety is important for these effects, the Michael addition is reversible and it can be assumed that also other parts of the molecules will moderate any given biological activity. In this investigation, the cytotoxicity of 23 a-methylene-g-lactones towards normal breast epithelial MCF-10A cells as well as breast cancer JIMT-1 cells is compared. Most of the investigated compounds are semisynthetic derivatives prepared by the condensation of the natural product damsin (1) with aldehydes. The two cell lines were treated with various concentrations of the compounds in dose response assays, and the 50 % inhibitory concentration (IC50) was determined from dose response curves. The IC50 values were found to depend strongly on the overall structure. The ratio between the IC50 values for MCF-10A and JIMT-1 cells, as a measure for the selectivity of a compound to kill cancer cells, was calculated, and found to vary between just over 1 to more than 10. The most potent derivatives formed from the condensation of 1 with aromatic aldehydes towards JIMT-1 cells are 3a and 3i, both with ratios between the IC50 values for MCF-10A and JIMT-1 cells close to 5. Also some aldol condensation products with acyclic aldehydes, i.e. 3r and 3u, were equally potent, and the latter showed the highest selectivity (ratio > 10). Structure-activity relationships that may explain the observed differences in potency and selectivity are discussed.
Trichilianones A-D, Novel Cyclopropane-Type Limonoids from Trichilia adolfi
(Multidisciplinary Digital Publishing Institute, 2021) Ivan Limachi; Mariela González-Ramírez; Sophie Manner; Juan C. Ticona; Efraín Salamanca; Alberto Giménez; Olov Sterner
The fractionation of an ethanol extract of the bark of Trichilia adolfi yielded four novel limonoids (trichilinones A-D, 1-4), with five fused rings and related to the hortiolide-type limonoids. Starting with an ε-lactone, which is α,β-unsaturated in trichilinones A and D (1 and 4), attached to a tetrahydrofuran ring that is connected to an unusual bicyclo [5.1.0] hexane system, joined with a cyclopentanone with a 3-furanyl substituent [(2-oxo)-furan-(5H)-3-yl in trichilinone D (4)], the four compounds isolated display a new 7/5/3/5/5 limonoid ring system. Their structures were established based on extensive analysis of NMR spectroscopic data. As the crude extract possessed anti-leishmanial properties, the compounds were assayed for cytotoxic and anti-parasitic activities in vitro in murine macrophages cells (Raw 264.7) and leishmania promastigotes (L. amazoniensis and L. braziliensis), respectively. The compounds showed moderate cytotoxicity (approximately 70 μg/mL), but are not responsible for the leishmanicidal effect of the extract.
Trichilones A–E: New Limonoids from Trichilia adolfi
(Multidisciplinary Digital Publishing Institute, 2021) Mariela González-Ramírez; Ivan Limachi; Sophie Manner; Juan C. Ticona; Efraín Salamanca; Alberto Giménez; Olov Sterner
In addition to the trichilianones A-D recently reported from Trichilia adolfi, a continuing investigation of the chemical constituents of the ethanol extract of the bark of this medicinal plant yielded the five new limonoids 1-5. They are characterized by having four fused rings and are new examples of prieurianin-type limonoids, having a ε-lactone which in 4 and 5 is α, β- unsaturated. The structures of the isolated metabolites were determined by high field NMR spectroscopy and HR mass spectrometry. The new metabolites were shown to have the ε-lactone fused with a tetrahydrofuran ring which is connected to an oxidized hexane ring joined with a cyclo-pentanone having a 3-furanyl substituent. As the crude extract possesses antileishmanial activity, the compounds were assayed for cytotoxic and antiparasitic activities in vitro in murine macrophage cells (raw 264.7 cells) and in Leishmania amazoniensis as well as L. braziliensis promastigotes. Metabolites 1-3 and 5 showed moderate cytotoxicity (between 30-94 µg/mL) but are not responsible for the antileishmanial effect of the extract.