Browsing by Autor "Olov Sterner"

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1,3,7-TRIMETHYLGUANINE FROM THE LICHEN STEREOCAULON RAMULOSUM
(Universidad Autónoma del Estado de México, 2008) José Vila; Patricia Mollinedo; Yonny Flores; Olov Sterner
"Chromatographic fractionation of an acetone extract of the lichen Stereocaulon ramulosum afforded 1,3,7- trimethylguanine (1), perlatolic acid (2), methyl β-orcinolcarboxylate (3), atranorin (4) and galactitol (5). The structures were elucidated using NMR spectroscopy and mass spectrometry./ Cinco compuestos fueron aislados del extracto acetónico del Stereocaulon ramulosum, 1,3,7-trimetilguanina (1), acido perlatólico (2), β- orcinolcarboxilato de metilo (3), atranorina (4) y galactitol (5). Las estructuras moleculares fueron elucidadas por métodos espectroscópicos de RMN y espectrometría de masas."
A 5-methylcoumarin glucoside and a coumestan derivative from Mutisia orbignyana.
(Lund University, 2009) Yonny Flores; Gloria Rodrigo; Patricia Mollinedo; Björn Åkesson; Olov Sterner; Giovanna R. Almanza
The ethanolic extract of the aerial parts from Mutisia orbignyana afforded two major compounds: mutisifurocoumarin (1) and 5-methylcoumarine-4-β-glucoside (2). The completely assignment of 1H and 13C NMR data of compound (2) is presented for the first time as well as some reassignments of 13C NMR spectrum for compound (1), applying 2D NMR techniques. In addition, the antiproliferative effect on colon cancer cells (CaCo2) and the scavenging effect using the ABTS test were measured The results showed an interesting scavenging activity and a non proliferative effect on colon cancer cells./El extracto etanólico de las partes aéreas de Mutisia orbignyana presentó dos compuestos mayoritarios: mutisifurocumarina (1) y 5-metilcumarina-4-β-glucosilada (2). El asignamiento completo de RMN de 1H y 13C del compuesto (2) es presentado por primera vez, así como también algunos reasignamientos del espectro de RMN13C del compuesto (1), en ambos casos se aplico técnicas de RMN 2D. Además, se midió el efecto antiproliferativo sobre células cancerosas de colon (CaCo2) y el efecto como inhibidores de radicales libres usando la prueba ABTS, tanto de extractos como de compuestos puros. Los resultados muestran un interesante efecto antiradicalario en ABTS y un efecto no-proliferativo sobre células cancerosas de colon.
A new facile and efficient synthesis of trans-(+)-sobrerol by biotransformation of α-pinene using extremophiles microorganisms
(Thieme Medical Publishers (Germany), 2009) LA Vilaseca; J Quillaguamán; Lorena Román Fuentes; Olov Sterner
Trans-(+)-sobrerol is a hydroxyl containing monocyclic terpenoid resulting from the autoxidation of α-pinene in presence of air and water. It presents pharmacological properties as mucolytic agent and clinical trials have confirmed its efficacy in relieving obstructive symptoms in patients suffering from chronic bronchitics [1].
A novel cytotoxic terpenoid from the flowers of Kaunia lasiophthalma Griseb
(Elsevier BV, 2014) Eliana M. Maldonado; Daniel Svensson; Stina Oredsson; Olov Sterner
Anti-cancer stem cell activity of a sesquiterpene lactone isolated from Ambrosia arborescens and of a synthetic derivative
(Public Library of Science, 2017) Wendy Soria Sotillo; Rodrigo Villagomez; Sandra Smiljanic; Xiaoli Huang; Atena Malakpour; Sebastian Kempengren; Gloria Rodrigo; Giovanna R. Almanza; Olov Sterner; Stina Oredsson
New regimens are constantly being pursued in cancer treatment, especially in the context of treatment-resistant cancer stem cells (CSCs) that are assumed to be involved in cancer recurrence. Here, we investigated the anti-cancer activity of sesquiterpene lactones (SLs) isolated from Ambrosia arborescens and of synthetic derivatives in breast cancer cell lines, with a specific focus on activity against CSCs. The breast cancer cell lines MCF-7, JIMT-1, and HCC1937 and the normal-like breast epithelial cell line MCF-10A were treated with the SLs damsin and coronopilin, isolated from A. arborescens, and with ambrosin and dindol-01, synthesized using damsin. Inhibitory concentration 50 (IC50) values were obtained from dose-response curves. Based on IC50 values, doses in the μM range were used for investigating effects on cell proliferation, cell cycle phase distribution, cell death, micronuclei formation, and cell migration. Western blot analysis was used to investigate proteins involved in cell cycle regulation as well as in the NF-κB pathway since SLs have been shown to inhibit this transcription factor. Specific CSC effects were investigated using three CSC assays. All compounds inhibited cell proliferation; however, damsin and ambrosin were toxic at single-digit micromolar ranges, while higher concentrations were required for coronopilin and dindol-01. Of the four cell lines, the compounds had the least effect on the normal-like MCF-10A cells. The inhibition of cell proliferation can partly be explained by downregulation of cyclin-dependent kinase 2. All compounds inhibited tumour necrosis factor-α-induced translocation of NF-κB from the cytoplasm to the nucleus. Damsin and ambrosin treatment increased the number of micronuclei; moreover, another sign of DNA damage was the increased level of p53. Treatment with damsin and ambrosin decreased the CSC subpopulation and inhibited cell migration. Our results suggest that these compounds should be further investigated to find efficient CSC-inhibiting compounds.
Antileishmanial metabolites from Lantana balansae
(Springer Science+Business Media, 2016) Eliana M. Maldonado; Efraín Salamanca; Alberto Giménez; Olov Sterner
Eleven compounds, 12-oxo-phytodienoic acid (1), persicogenin (2), eriodictyol 3′,4′,7-trimethyl ether (3), phytol (4), spathulenol (5), 4-hydroxycinnamic acid (6), onopordin (7), 5,8,4′-trihydroxy-7,3′-dimethoxyflavone (8), quercetin (9), jaceosidin (10), and 8-hydroxyluteolin (11), were isolated from an ethanol extract of Lantana balansae Briq., Verbenaceae, that was found to possess antileishmanial activity. The structures of the compounds were determined by NMR spectroscopy and HR mass spectrometry, and 1, 2, 3, 7, 8 and 9 were investigated for antiprotozoal activity toward promastigotes of Leishmania amazonensis and Leishmania braziliensis. Compound 1 was shown to be the most potent, with the IC50 values 2.0 μM toward L. amazonensis and 0.68 μM toward L. braziliensis, although less potent than the positive control Amphotericin B. All compounds have been reported previously, but this is the first report of the isolation of a cyclopentenone fatty acid (1) and flavanones (2 and 3) from a Lantana species.
Antileishmanial metabolites from Trixis antimenorrhoea
(Elsevier BV, 2014) Eliana M. Maldonado; Efraín Salamanca; Alberto Giménez; Gloria Saavedra; Olov Sterner
Antioxidant and Antimutagenic Polyisoprenylated Benzophenones and Xanthones from Rheedia acuminata
(SAGE Publishing, 2011) Giovanna R. Almanza; Raúl Quispe; Patricia Mollinedo; Gloria Rodrigo; Ery Odette Fukushima; Rodrigo Villagomez; Björn Åkesson; Olov Sterner
Dichloromethane extract of the stem bark of Rheedia acuminata yielded three benzophenones with antioxidant activity, the new one named acuminophenone A (1), guttiferone K (2) and isoxanthochymol (3), along with the known xanthones formoxanthone C (4) and macluraxanthone (5). The structures were established through interpretation of their spectroscopic data, the stereochemistry of compounds (1) and (2) were resolved by experimental and computational experiments and their antioxidant activities were measured using the DPPH, ABTS and TEAC assays. The antioxidant results showed that metabolites 1, 4 and 5 had a better antioxidant activity than the reference compound quercetin. In addition, we evaluate the mutagenicity and antimutagenicity of the CH2Cl2 extract as well as of the free radical scavenger compounds 1, 4 and 5 by the AMES Salmonella/microsomal test. No mutagenicity was found in the CH2Cl2 extract using Salmonella typhimurium strains TA98, TA100, TA102, TA1537 and TA1538, with or without S9 metabolic activation. The pure compounds neither showed mutagenicity in TA 102 strain and the most important result was the strong reduction of mutagenic effect induced by hydrogen peroxide in S. typhimurium TA102, with or without S9, showed by the compounds 1 (more than 93%) and 4 (more than 88%) at 0.02 microg/plate.
Benzochromenes from the roots of Bourreria pulchra
(Elsevier BV, 2009) Gilda J. Erosa-Rejón; Alejandro Yam-Puc; Manuel Jesús Chan-Bacab; Alberto Giménez-Turbax; Efraín Salamanca; Luis M. Peña-Rodrı́guez; Olov Sterner
Bioactive alkenylphenols from Piper obliquum
(Elsevier BV, 2008) Carola Valdivia; Nieves Márquez; John Eriksson; Antonio Vilaseca; Eduardo Muñóz; Olov Sterner
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.
Discovery of a potent and long-acting bronchorelaxing capsazepinoid, RESPIR 4-95
(Elsevier BV, 2007) Staffan Skogvall; María F. Dalence-Guzmán; Magnus Berglund; Katrin J. Svensson; Admira Mesic; Per Jönsson; C. G. A. Persson; Olov Sterner
Effect of Natural and Semisynthetic Pseudoguianolides on the Stability of NF-κB:DNA Complex Studied by Agarose Gel Electrophoresis
(Public Library of Science, 2015) Rodrigo Villagomez; Rajni Hatti‐Kaul; Olov Sterner; Giovanna R. Almanza; Javier A. Linares‐Pastén
The nuclear factor κB (NF-κB) is a promising target for drug discovery. NF-κB is a heterodimeric complex of RelA and p50 subunits that interact with the DNA, regulating the expression of several genes; its dysregulation can trigger diverse diseases including inflammation, immunodeficiency, and cancer. There is some experimental evidence, based on whole cells studies, that natural sesquiterpene lactones (Sls) can inhibit the interaction of NF-κB with DNA, by alkylating the RelA subunit via a Michael addition. In the present work, 28 natural and semisynthetic pseudoguianolides were screened as potential inhibitors of NF-κB in a biochemical assay that was designed using pure NF-κB heterodimer, pseudoguianolides and a ~1000 bp palindromic DNA fragment harboring two NF-κB recognition sequences. By comparing the relative amount of free DNA fragment to the NF-κB - DNA complex, in a routine agarose gel electrophoresis, the destabilizing effect of a compound on the complex is estimated. The results of the assay and the following structure-activity relationship study, allowed the identification of several relevant structural features in the pseudoguaianolide skeleton, which are necessary to enhance the dissociating capacity of NF-κB-DNA complex. The most active compounds are substituted at C-3 (α-carbonyl), in addition to having the α-methylene-γ-lactone moiety which is essential for the alkylation of RelA.
Effects of capsazepine on human small airway responsiveness unravel a novel class of bronchorelaxants
(Elsevier BV, 2006) Staffan Skogvall; Magnus Berglund; María F. Dalence-Guzmán; Katrin J. Svensson; Per Jönsson; C. G. A. Persson; Olov Sterner
Leishmanicidal activity of onopordopicrin isolated from the leaves of Brachylaena discolor
(University of Bern, 2018) Julião Monjane; Diandra Capusiri; Alberto Giménez; Olov Sterner
Brachylaena discolor (Asteraceae) is a medicinal plant used in Mozambique to treat stomachache, tuberculosis, and diabetes. To discover new lead compounds with leishmanicidal activity, a methanolic extract of the leaves of this plant was investigated. Through fractionation, employing several chromatographic methods, two sesquiterpene lactones onopordopicrin (1) and its germacronolide epoxide derivative (2), together with other ten know phenolic compounds derivatives (3-12) were isolated. The structures of the isolated compounds were determined by spectroscopic methods, mainly 1D and 2D NMR experiments, as well as by comparing their spectroscopic data as reported in the literature. Compounds 1 and 2 were evaluated for their leishmanicidal activity using the Colorimetric method-XXT. Compound 1 showed a significant leishmanicidal activity against Leishmania amazonensis and L. braziliensis (IC50 values 39.6 and 27.9 μM, respectively) as compared to miltefosine (12.5 and 12.0 μM, respectively), a currently used agent to treat leishmaniosis. While compound 2 was inactive against both stains tested with IC50 values >50μM compared with the same agent. Compounds 3-12 were not assayed for leishmanicidal activity. This is the first study reporting the above-mentioned activity of onopordopicrin (1). The results could suggest that compound 1 is a promising lead structure to treat leishmaniosis.
MORE INVESTIGATIONS IN POTENT ACTIVITY AND RELATIONSHIP STRUCTURE OF THE LICHEN ANTIBIOTIC (+)-USNIC ACID AND ITS DERIVATE DIBENZOYLUSNIC ACID
(Universidad Autónoma del Estado de México, 2008) Marcela Melgarejo; Olov Sterner; Julio Enrique Ocampo Castro; Patricia Mollinedo
"By reacting R-(+)-usnic acid (1) with benzoyl chloride in presence of pyridine gave the dibenzoylusnic acid (2). The antibacterial activity and relationship structure of acid usnic an old lichen drug and its derivate dibenzoylusnic acid was studied against nine ATCC bacteria and one bacterium clinical isolate./ Mediante la reacción del R-(+)-acido úsnico con cloruro de benzoilo en presencia de piridina se obtuvo el acido dibenzoilusnico. Se estudio la relación de actividad antibacteriana y estructura del R-(+)-acido úsnico y su derivado el acido dibenzoilúsnico contra nueve bacterias ATCC y una bacteria clínicamente aislada."
Natural and Semi-Synthetic Pseudoguaianolides as Inhibitors of NF-κB
(Scientific Research Publishing, 2014) Rodrigo Villagomez; Juan A. Collado; Eduardo Muñóz; Giovanna R. Almanza; Olov Sterner
Damsin (1) is a natural pseudoguaianolide sesquiterpene that inhibits NF-κB, a protein complex that controls the transcription of DNA in mammalian cells, and has a potential for standing model for the development of new anti-cancer lead structures. In order to do a preliminary structure-activity study and improve the anti-cancer activity, fourteen derivatives and analogs were prepared and evaluated. These were chosen to represent both structural diversity and structural novelty. The importance of α methylene-γ-lactone moiety for the anti-cancer activity was confirmed, even though other features in the scaffold were shown to be important for the activity. In some cases a new substitution negatively affected the initial activity, however, two analogues, indolo [3,2-c]-4-desoxydamsin (5) and ambrosin (6), were found to be more potent.
Natural Pseudoguaianolides Prepared from Damsin
(Springer Science+Business Media, 2015) Rosa Villagomez; M. Quiroz; A. Tito; Olov Sterner; Giovanna R. Almanza
New pregaliellalactonoids from Galiella rufa
(Elsevier BV, 2015) Zilma Escobar; Headley Williams; Richard P. Phipps; Deepa Karunakaran; Jonathan Steele; Olov Sterner
OLEANANE-TYPE TRITERPENES AND DERIVATIVES FROM SEED COAT OF BOLIVIAN CHENOPODIUM QUINOA GENOTYPE “SALAR”
(Lund University, 2005) Yonny Flores; Carlos Barrera-Díaz; Fidel Garay; Osmar Colque; Olov Sterner; Giovanna R. Almanza
"Bolivia is the first world exporter of quinoa (Chenopodium quinoa Willd) genotype “salar”. In its natural state quinoa has a coating of bitter-tasting (saponins), making it essentially unpalatable. Most of quinoa exported from Bolivia has been processed to remove this coating. These seed coat residues contain a high level of oleanane-type saponins. From those residues two oleanane-type triterpenes were found as the major sapogenins and their structures were identified as: oleanolic acid and deoxyphytolaccagenic acid in base of NMR means. Furthermore, two derivatives of oleanolic acid were obtained: 28-Omethyl and 3-O-acetyloleanolic acid. The importance of oleanolic acid content in this industrial residue is discussed."