0000000000241142
AUTHOR
Benjamin Wiench
showing 18 related works from this author
Anticancer activities of six selected natural compounds of some Cameroonian medicinal plants.
2011
BACKGROUND: Natural products are well recognized as sources of drugs in several human ailments. In the present work, we carried out a preliminary screening of six natural compounds, xanthone V(1) (1); 2-acetylfuro-1,4-naphthoquinone (2); physcion (3); bisvismiaquinone (4); vismiaquinone (5); 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone (6) against MiaPaCa-2 pancreatic and CCRF-CEM leukemia cells and their multidrug-resistant subline, CEM/ADR5000. Compounds 1 and 2 were then tested in several other cancer cells and their possible mode of action were investigated. METHODOLOGY/FINDINGS: The tested compounds were previously isolated from the Cameroonian medicinal plants Vismia laurentii (1,…
Activity of the antiestrogenic cajanin stilbene acid towards breast cancer
2014
Antiestrogenic therapy is a mainstay for estrogen receptor (ERα)-positive breast cancer. Due to the development of resistance to established antihormones such as tamoxifen, novel compounds are required. The low abundant cajanin stilbene acid (CSA) recently isolated by us from Pigeon Pea (Cajanus cajan) has structural similarities with estrogen. We analyzed the cytotoxic and anticancer activity of CSA in ERα-positive and -negative human breast cancer cells in vitro, in vivo and in silico. CSA exerts anticancer and antiestrogenic activities towards ERα-positive breast cancer, and it showed cytotoxicity towards tamoxifen-resistant MCF-7 cells, implying that CSA may be active against tamoxifen-…
Utilizing inherent fluorescence of therapeutics to analyze real-time uptake and multi-parametric effector kinetics.
2011
Abstract The precise detection of pharmaceutical drug uptake and knowledge of a drug’s efficacy at the single-cell level is crucial for understanding a compound’s performance. Many pharmaceutical drugs, like the model substances Doxorubicin, Mitoxantrone or Irinotecan, have a distinctive natural fluorescence that can be readily exploited for research purposes. Utilizing this respective natural fluorescence, we propose a method analyzing simultaneously in real-time the efficiency, effects and the associated kinetics of compound-uptake and efflux in mammalian cells by flow cytometry. We show that real-time flow cytometric quantification of compound-uptake is reliably measured and that analyzi…
Cytotoxicity and modes of action of four naturally occuring benzophenones: 2,2′,5,6′-Tetrahydroxybenzophenone, guttiferone E, isogarcinol and isoxant…
2012
Abstract Introduction The emergence of drug-resistant cancer cells drastically reduces the efficacy of many antineoplasic agents and, consequently, increases the frequency of therapeutic failure. Benzophenones are known to display many pharmacological properties including cytotoxic activities. The present study was aimed at investigating the cytotoxicity and the modes of action of four naturally occurring benzophenones 2,2′,5,6′-tetrahydroxybenzophenone ( 1 ), isogarcinol ( 2 ), isoxanthochymol ( 3 ) and guttiferone E ( 4 ) on a panel of eleven cancer cell lines including various sensitive and drug-resistant phenotypes. Methods The cytotoxicity of the compounds was determined using a resazu…
Cytotoxicity and modes of action of four Cameroonian dietary spices ethno-medically used to treat cancers: Echinops giganteus, Xylopia aethiopica, Im…
2013
Abstract Ethnopharmacological relevance. Echinops giganteus , Imperata cylindrica , Piper capense and Xylopia aethiopica are four medicinal spices used in Cameroon to treat cancers. Aim of the study The above plants previously displayed cytotoxicty against leukemia CCRF-CEM and CEM/ADR5000 cell lines as well as human pancreatic MiaPaCa-2 cells. The present study aims at emphasizing the study of the cytotoxicity and the modes of action of the above plants on a panel of ten cancer cell lines including various sensitive and drug-resistant phenotypes. The study has been extended to the isolation of the bioactive constituents from Echinops giganteus . Materials and methods The cytotoxicity of th…
Cytotoxicity of a naturally occurring furoquinoline alkaloid and four acridone alkaloids towards multi-factorial drug-resistant cancer cells
2015
Abstract Introduction Chemotherapy is one of the preferred mode of treatment of malignancies, but is complicated by the expression of diverse resistance mechanisms of cancer cells. Methods In the present study, we investigated the cytotoxicity of five alkaloids including a furoquinoline montrofoline (1) and four acridones namely 1-hydroxy-4-methoxy-10-methylacridone (2), norevoxanthine (3), evoxanthine (4), 1,3-dimethoxy-10-methylacridone (5) against 9 drug-sensitive and multidrug-resistant (MDR) cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle, mitochondrial …
Abstract 4662: Shikonin causes cancer cell death by inducing mitochondrial dysfunction
2012
Abstract Shikonin, a naturally occurring napthoquinone, has been used in herbal formulations for the treatment of several inflammatory diseases in Traditional Chinese Medicine since decades. In recent studies, shikonin revealed remarkable anticancer activities and thereby is a promising candidate for cancer chemotherapy. However, the underlying cellular mechanisms and targets of shikonin are still unknown. Here, we showed that shikonin indeed exhibits strong cytotoxic effects on a panel of 15 different cancer cell lines also containing multi-drug resistant cells. The strongest effects were obtained on U937 leukemia cells. To better understand the underlying mechanisms, we performed a whole …
Intralaboratory validation of four in vitro assays for the prediction of the skin sensitizing potential of chemicals
2011
Abstract Allergic contact dermatitis is induced by repeated skin contact with an allergen. Assessment of the skin sensitizing potential of chemicals, agrochemicals, and especially cosmetic ingredients is currently performed with the use of animals. Animal welfare and EU legislation demand animal-free alternatives reflected in a testing and marketing ban for cosmetic ingredients beginning in 2013. The underlying mechanisms of induction and elicitation of skin sensitization are complex and a chemical needs to comply several properties being skin sensitizing. To account for the multitude of events in the induction of skin sensitization an in vitro test system will consist of a battery of vario…
Cytotoxicity and modes of action of three naturally occurring xanthones (8-hydroxycudraxanthone G, morusignin I and cudraxanthone I) against sensitiv…
2014
Abstract Background Resistance of cancer to chemotherapy remains a challenging issue for scientists as well as physicians. Naturally occurring xanthones possess a variety of biological activities such as anti-inflammatory, anti-bacterial, and anti-cancer effects. The present study was aimed at investigating the cytotoxicity and the modes of action of three naturally occurring xanthones namely, morusignin I (1), 8-hydroxycudraxanthone G (2) and cudraxanthone I (3) against a panel of nine cancer cell lines, including various sensitive and drug-resistant phenotypes. Methods The cytotoxicity of the compounds was determined using a resazurin reduction assay, whereas the caspase-Glo assay was use…
Activity of three cytotoxic isoflavonoids from Erythrina excelsa and Erythrina senegalensis (neobavaisoflavone, sigmoidin H and isoneorautenol) towar…
2013
Abstract Introduction Resistance of cancer cells to chemotherapy has become a worldwide concern. Naturally occuring isoflavonoids possess a variety of biological activities including anti-cancer effects. The present study was aimed at investigating the cytotoxicity and the modes of action of three naturally occuring isoflavonoids, neobavaisoflavone ( 1 ), sigmoidin H ( 2 ) and a pterocarpan that is a special type of isoflavonoid, isoneorautenol ( 3 ) against a panel of nine cancer cell lines, including various sensitive and drug-resistant phenotypes. Methods The cytotoxicity of the compounds was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect t…
Cytotoxicity and modes of action of five Cameroonian medicinal plants against multi-factorial drug resistance of tumor cells
2013
Abstract Ethnopharmacological relevance Beilschmiedia acuta Kosterm, Clausena anisata (Willd) Hook, Fagara tessmannii Engl., Newbouldia laevis Seem., and Polyscias fulva (Hiern) Harms. are medicinal plants used in Cameroonian traditional medicine in the treatment of various types of cancers. The present study aims at investigating 11 methanolic extracts from the above Cameroonian medicinal plants on a panel of human cancer cell lines, including various drug-resistant phenotypes. Possible modes of action were analyzed for two extracts from Beilschmiedia acuta and Polyscia fulva and alpha-hederin, the representative constituent of Polyscia fulva. Materials and methods Cytotoxicity was determi…
Cell cycle arrest and induction of apoptosis by cajanin stilbene acid from Cajanus cajan in breast cancer cells
2015
Abstract Background: The low abundant cajanin stilbene acid (CSA) from Pigeon Pea ( Cajanus cajan ) has been shown to kill estrogen receptor α positive cancer cells in vitro and in vivo . Downstream effects such as cell cycle and apoptosis-related mechanisms have not been analyzed yet. Material and methods: We analyzed the activity of CSA by means of flow cytometry (cell cycle distribution, mitochondrial membrane potential, MMP), confocal laser scanning microscopy (MMP), DNA fragmentation assay (apoptosis), Western blotting (Bax and Bcl-2 expression, caspase-3 activation) as well as mRNA microarray hybridization and Ingenuity pathway analysis. Results: CSA induced G2/M arrest and apoptosis …
Laurus nobilis L. Seed Extract Reveals Collateral Sensitivity in Multidrug-Resistant P-Glycoprotein-Expressing Tumor Cells.
2015
The frequent failure of standard cancer chemotherapy requires the development of novel drugs capable of killing otherwise drug-resistant tumors. Here, we have investigated a chloroform extract of Laurus nobilis seeds. Fatty acids and 23 constituents of the volatile fraction were identified by gas chromotography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS), in good agreement with (1)H NMR (nuclear magnetic resonance) spectrum. Multidrug-resistant P-glycoprotein-expressing CEM/ADR5000 leukemia cells were hypersensitive (collaterally sensitive) toward this extract compared to drug-sensitive CCRF-CEM cells, whereas CEM/ADR5000 cells were 2586-fold resista…
Cytotoxicity, anti-angiogenic, apoptotic effects and transcript profiling of a naturally occurring naphthyl butenone, guieranone A
2012
Abstract Background Malignant diseases are responsible of approximately 13% of all deaths each year in the world. Natural products represent a valuable source for the development of novel anticancer drugs. The present study was aimed at evaluating the cytotoxicity of a naphtyl butanone isolated from the leaves of Guiera senegalensis, guieranone A (GA). Results The results indicated that GA was active on 91.67% of the 12 tested cancer cell lines, the IC50 values below 4 μg/ml being recorded on 83.33% of them. In addition, the IC50 values obtained on human lymphoblastic leukemia CCRF-CEM (0.73 μg/ml) and its resistant subline CEM/ADR5000 (1.01 μg/ml) and on lung adenocarcinoma A549 (0.72 μg/m…
Antibacterial activity and cytotoxicity of selected Egyptian medicinal plants.
2011
Medicinal plants have been used as a source of remedies since ancient times in Egypt. The present study was designed to investigate the antibacterial activity and the cytotoxicity of the organic extracts from 16 selected medicinal plants of Egypt. The study was also extended to the isolation of the antiproliferative compound jaeschkeanadiol p-hydroxybenzoate (FH-25) from Ferula hermonis. The microbroth dilution was used to determine the minimal inhibitory concentration (MIC) of the samples against twelve bacterial strains belonging to four species, Providencia stuartii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli, while a resazurin assay was used to assess the cytoto…
Cytotoxicity and modes of action of 4'-hydroxy-2',6'-dimethoxychalcone and other flavonoids toward drug-sensitive and multidrug-resistant cancer cell…
2014
Abstract Introduction Resistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4′-hydroxy-2′,6′-dimethoxychalcone ( 1 ), cardamomin ( 2 ), 2′,4′-dihydroxy-3′,6′-dimethoxychalcone ( 3 )], and four flavanones [( S )-(–)-pinostrobin ( 4 ), ( S )-(–)-onysilin ( 5 ) and alpinetin ( 6 )] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types. Methods The resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometr…
Cytotoxicity of natural products and derivatives toward MCF-7 cell monolayers and cancer stem-like mammospheres
2015
Abstract Although cancer stem-like cells (CSCs) are rare, they can enter a non-proliferative or dormant state and resist therapy. Furthermore, quiescent CSCs are responsible for metastases that can appear after curative surgical treatment of a primary tumor. Because of drug resistance of CSCs, the development of novel therapies is urgently required that specifically target CSCs. Purpose The aim of the present study was to investigate the potential of a panel of natural products and derivatives to inhibit CSC-enriched mammospheres of MCF-7 breast cancer cells. Methods CD44high/CD24low cells were identified by flow cytometry and maintained as mammospheres. As a control, we used two clinically…
Cytotoxicity and Modes of Action of the Methanol Extracts of Six Cameroonian Medicinal Plants against Multidrug-Resistant Tumor Cells
2013
Introduction. The present study aims at evaluating the cytotoxicity of twelve parts from six Cameroonian medicinal plants on sensitive and drug-resistant cancer cell lines. We also studied the mode of action of the most active plants, Gladiolus quartinianus, Vepris soyauxii, and Anonidium mannii. Methods. The cytotoxicity of the extracts was determined using a resazurin assay. Flow cytometry was used for cell-cycle analysis and detection of apoptosis, analysis of mitochondrial membrane potential (MMP), and measurement of reactive oxygen species (ROS). Results. At 40 g/mL, three extracts showed a growth of CCRF-CEM leukemia cells by less than 50%. This includes the extracts from G. quartinia…