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Isabelle D B Arthaud,
Felipe A R Rodrigues,
Paula C Jimenez, Raquel C Montenegro,
Alysson L Angelim,
Vânia M M Maciel,
Edilberto R Silveira,
Hozana P S Freitas,
Thiciana S Sousa,
Otília D L Pessoa,
Tito M C Lotufo,
Letícia V Costa-Lotufo
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ABSTRACT: Continuing search for anticancer compounds from the marine environment, we have studied microorganisms that inhabit intertidal sediments of the northeastern Brazilian coast. Of the 32 strains isolated, 13 were selected for biological evaluation of their crude extracts. The acetate extract obtained from a Gram-negative bacterium was strongly active against cancer cell lines with IC(50) values that ranged from 0.04 (HL60 leukemia cells) to 0.26 μg/ml (MDA MB-435 melanoma cells). The bacterium was identified as a Pseudoalteromonas sp. based on 16S rRNA gene sequencing. A bioassay-guided fractionation of the active extract led to the isolation of prodigiosin, a well-known tripyrrole red pigment with immunosuppressive and anticancer activities. Further experiments with ErbB-2 overexpressing cell lines, including HB4a-C3.6 (moderate overexpression), HB4a-C5.2 (high overexpression), and the parental HB4a cell line, were performed. Prodigiosin was moderately active toward HB4a cells with an IC(50) of 4.6 μg/ml, while it was 115 and 18 times more active toward HB4a-C3.6 cells (IC(50) of 0.04 μg/ml) and HB4a-C5.2 (IC(50) of 0.26 μg/ml) cells, respectively. These data suggest that, in spite of its previously described apoptosis-inducing properties, prodigiosin can selectively recognize cells overexpressing ErbB-2, which could be highly appealing in human breast cancer therapy.
Chemistry & Biodiversity 02/2012; 9(2):418-27. · 1.80 Impact Factor
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ABSTRACT: A synthetic method to obtain α- and β-pyran naphthoquinones 10 and 11 with a hydroxyl substituent on the aromatic ring was developed. Two series of α- and β-pyran naphthoquinones were obtained from the 8-hydroxy-lawsone, and their anticancer properties were evaluated against four tumor cell lines. In general, the new compounds displayed good activity, possibly indicating that these compounds have increased pro-oxidant capacity. The 9-hydroxy-α-lapachone and 7-hydroxy-β-lapachone analogues of the natural products α-lapachone and β-lapachone were successfully produced by this methodology.
Organic & Biomolecular Chemistry 06/2011; 9(11):4315-22. · 3.70 Impact Factor
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ABSTRACT: The antiproliferative effects of twenty-eight tetrasubstituted olefins bearing a ferrocenyl group, including six never-reported compounds, were evaluated against SF-295 (human glioblastoma), HCT-8 (human colon cancer), MDA-MB-435 (human melanoma) and HL-60 (human promyelocytic leukemia) using the MTT test. IC(50) values were determined for twenty-three active compounds and of these, ten compounds had IC(50) values lower than 2 μM on one or more cell lines. Of all the compounds, only two produced significant amounts of ROS on HL-60 cells, and ROS production and growth inhibition could not be correlated. The ten most antiproliferative compounds were tested for their hemolytic activity on mouse erythrocytes. Five compounds showing high antiproliferative activity and low hemolytic activity were thus identified for further study.
European journal of medicinal chemistry 05/2011; 46(9):3778-87. · 3.27 Impact Factor
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ABSTRACT: Biflorin, an ortho-naphthoquinone, is an active compound found in the roots of Capraria biflora L. It has been reported that biflorin presents anticancer activity, inhibiting both tumor cell line growth in culture and tumor development in mice. The aim of this study was to examine the effectiveness of biflorin treatment using both in-vitro and in-vivo melanoma models. Biflorin displayed considerable cytotoxicity against all tested cell lines, with half maximal inhibitory concentration values ranging from 0.58 μg/ml in NCI H23 (human lung adenocarcinoma) to 14.61 μg/ml in MDA-MB-231 (human breast cancer) cell lines. In a second set of experiments using B16 melanoma cells as a model, biflorin reduced cell viability but did not cause significant increase in the number of nonviable cells. In addition, the DNA synthesis was significantly inhibited. Flow cytometry analysis showed that biflorin may lead to an apoptotic death in melanoma cells, inducing DNA fragmentation and mitochondria depolarization, without affecting membrane integrity. In B16 melanoma-bearing mice, administration of biflorin (25mg/day) for 10 days inhibited tumor growth, and also increased the mean survival rate from 33.3±0.9 days (control) to 44.5±3.4 days (treated). Our findings suggest that biflorin may be considered as a promising lead compound for designing new drugs to be used in the treatment of melanoma.
Melanoma Research 03/2011; 21(2):106–114. · 2.19 Impact Factor
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ABSTRACT: Biflorin, an ortho-naphthoquinone, is an active compound found in the roots of Capraria biflora L. It has been reported that biflorin presents anticancer activity, inhibiting both tumor cell line growth in culture and tumor development in mice. The aim of this study was to examine the effectiveness of biflorin treatment using both in-vitro and in-vivo melanoma models. Biflorin displayed considerable cytotoxicity against all tested cell lines, with half maximal inhibitory concentration values ranging from 0.58 μg/ml in NCI H23 (human lung adenocarcinoma) to 14.61 μg/ml in MDA-MB-231 (human breast cancer) cell lines. In a second set of experiments using B16 melanoma cells as a model, biflorin reduced cell viability but did not cause significant increase in the number of nonviable cells. In addition, the DNA synthesis was significantly inhibited. Flow cytometry analysis showed that biflorin may lead to an apoptotic death in melanoma cells, inducing DNA fragmentation and mitochondria depolarization, without affecting membrane integrity. In B16 melanoma-bearing mice, administration of biflorin (25mg/day) for 10 days inhibited tumor growth, and also increased the mean survival rate from 33.3±0.9 days (control) to 44.5±3.4 days (treated). Our findings suggest that biflorin may be considered as a promising lead compound for designing new drugs to be used in the treatment of melanoma.
Melanoma research 02/2011; 21(2):106-14. · 2.06 Impact Factor
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Raísa da R Reis,
Elisa C Azevedo,
Maria Cecília B V de Souza,
Vitor Francisco Ferreira, Raquel C Montenegro,
Ana Jérsia Araújo,
Cláudia Pessoa,
Letícia V Costa-Lotufo,
Manoel O de Moraes,
José D B M Filho,
Alessandra M T de Souza,
Natasha C de Carvalho,
Helena C Castro,
Carlos R Rodrigues,
Thatyana R A Vasconcelos
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ABSTRACT: A series of 2-(benzo[d]thiazol-2-yl)-8-substituted-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones (3a-g) have been synthesized and evaluated for their in vitro antiproliferative activities against four human cancer cell lines: MDA-MB-435 (breast), HL-60 (leukemia), HCT-8 (colon) and SF-295 (central nervous system). The results showed that the compounds 3b (2-(benzo[d]thiazol-2-yl)-8-methyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) and 3c (2-(benzo[d]thiazol-2-yl)-8-bromo-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) exhibited good cytotoxicity for three cell lines with IC(50) values lower than 5 μg/mL. Analysis of theoretical toxicity risks have shown medium tumorigenic and irritant risks related to 3b and 3c in contrast to doxorubicin, the positive control.
European journal of medicinal chemistry 02/2011; 46(4):1448-52. · 3.27 Impact Factor
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ABSTRACT: Clerodane diterpenes have demonstrated cytotoxic, antiplasmodial and anti-ulcer properties. In the present work, we determined the cytotoxic effect of casearin L (Cas L), O (Cas O) and X (Cas X) and (-)-hardwickiic acid isolated from Casearia sylvestris leaves, and investigated the underlying mechanisms involved in in vitro cell death induced by Cas X in HL-60 leukemia cells (0.7, 1.5 and 3.0μM). Cytotoxicity tests demonstrated that Cas X was the most active compound studied, showing greater cytotoxic effects against CEM and HL-60 lines (IC(50) of 0.4μM) and human peripheral blood mononuclear cells (PBMC, IC(50) of 1.2μM). After 24h exposure, Cas X caused a decrease in 5-bromo-20-deoxyuridine (BrdU) incorporation (36.6 and 24.5% labeling at 0.7 and 1.5μM, respectively), reduction in viability, and increase in apoptotic and necrotic leukemia cells in a dose-dependent manner evidenced by the trypan blue and AO/EB (acridine orange/ethidium bromide) assays. Moreover, Cas X-treated cells exhibited nuclear fragmentation and cytoplasmic vacuolization depending on the concentration tested. These characteristics of apoptosis or secondary necrosis were confirmed by flow cytometry which revealed DNA fragmentation, phosphatidylserine externalization, activation of the effector caspases 3/7 and mitochondrial depolarization. We then found evidence that Cas X causes cell death via apoptotic pathways, corroborating the potential of casearins as compounds with promising antitumor-related properties.
Chemico-biological interactions 12/2010; 188(3):497-504. · 2.46 Impact Factor
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Edmundo L R Pereira,
Patrícia D L Lima,
André S Khayat,
Marcelo O Bahia,
Franciglauber S Bezerra,
Manoel Andrade-Neto, Raquel C Montenegro,
Cláudia Pessoa,
Letícia V Costa-Lotufo,
Manoel O Moraes,
France K N Yoshioka,
Giovanny R Pinto,
Rommel R Burbano
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ABSTRACT: Despite the remarkable progress in the characterization of the molecular pathogenesis of glioblastoma multiforme (GBM), these tumors remain incurable and, in most cases, refractory to aggressive cytotoxic treatments. We conducted a morphological and cytogenetic study in two GBM cell lines (U343 and AHOL1), before and after treatment with pisosterol (at 0.5, 1.0 and 1.8 µg ml(-1) ), a triterpene isolated from the fungus Pisolithus tinctorius. No significant alteration was observed in the morphology and frequency of chromosomal abnormalities in the cell lines analyzed after treatment with pisosterol. Using fluorescence in situ hybridization analysis with a locus-specific probe for C-MYC showed that 72% of U343 and 65% of AHOL1 cells contained more than two alleles of C-MYC before treatment. After treatment, no effects were detected at lower concentrations of pisosterol (0.5 and 1.0 µg ml(-1) ). However, at 1.8 µg ml(-1) of pisosterol, only 33% of U343 cells and 15% of AHOL1 cells presented more than two fluorescent signals, suggesting that pisosterol blocks the cells with gene amplification. Cells that do not show a high degree of C-MYC gene amplification have a less aggressive and invasive behavior and are easy targets for chemotherapy. Therefore, further studies are needed to examine the use of pisosterol in combination with conventional anti-cancer therapy. Copyright © 2010 John Wiley & Sons, Ltd.
Journal of Applied Toxicology 11/2010; · 2.48 Impact Factor
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Marne C Vasconcellos,
Dinara J Moura,
Renato M Rosa,
Miriana S Machado,
Temenouga N Guecheva,
Izabel Villela,
Bruna F Immich, Raquel C Montenegro,
Aluísio M Fonseca,
Telma L G Lemos,
Maria Elisabete A Moraes,
Jenifer Saffi,
Letícia V Costa-Lotufo,
Manoel O Moraes,
João A P Henriques
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ABSTRACT: Biflorin is a natural quinone isolated from Capraria biflora L. Previous studies demonstrated that biflorin inhibits in vitro and in vivo tumor cell growth and presents potent antioxidant activity. In this paper, we report concentration-dependent cytotoxic, genotoxic, antimutagenic, and protective effects of biflorin on Salmonella tiphymurium, yeast Saccharomyces cerevisiae, and V79 mammalian cells, using different approaches. In the Salmonella/microsome assay, biflorin was not mutagenic to TA97a TA98, TA100, and TA102 strains. However, biflorin was able to induce cytotoxicity in haploid S. cerevisiae cells in stationary and exponential phase growth. In diploid yeast cells, biflorin did not induce significant mutagenic and recombinogenic effects at the employed concentration range. In addition, the pre-treatment with biflorin prevented the mutagenic and recombinogenic events induced by hydrogen peroxide (H(2)O(2)) in S. cerevisiae. In V79 mammalian cells, biflorin was cytotoxic at higher concentrations. Moreover, at low concentrations biflorin pre-treatment protected against H(2)O(2)-induced oxidative damage by reducing lipid peroxidation and DNA damage as evaluated by normal and modified comet assay using DNA glycosylases. Our results suggest that biflorin cellular effects are concentration dependent. At lower concentrations, biflorin has significant antioxidant and protective effects against the cytotoxicity, genotoxicity, mutagenicity, and intracellular lipid peroxidation induced by H(2)O(2) in yeast and mammalian cells, which can be attributed to its hydroxyl radical-scavenging property. However, at higher concentrations, biflorin is cytotoxic and genotoxic.
Archive für Toxikologie 10/2010; 84(10):799-810. · 4.67 Impact Factor
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José Delano B Marinho-Filho,
Daniel P Bezerra,
Ana J Araújo, Raquel C Montenegro,
Claudia Pessoa,
Jaécio C Diniz,
Francisco A Viana,
Otília D L Pessoa,
Edilberto R Silveira,
Manoel O de Moraes,
Letícia V Costa-Lotufo
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ABSTRACT: (+)-Cordiaquinone J is a 1,4-naphthoquinone isolated from the roots of Cordia leucocephala that has antifungal and larvicidal effects. However, the cytotoxic effects of (+)-cordiaquinone J have never being explored. In the present study, the effect of (+)-cordiaquinone J on tumor cells viability was investigated, showing IC(50) values in the range of 2.7-6.6muM in HL-60 and SF-295 cells, respectively. Studies performed in HL-60 leukemia cells indicated that (+)-cordiaquinone J (1.5 and 3.0muM) reduces cell viability and 5-bromo-2-deoxyuridine incorporation after 24h of incubation. (+)-Cordiaquinone J showed rapid induction of apoptosis, as indicated by phosphatidylserine externalization, caspase activation, DNA fragmentation, morphologic changes, and rapid induction of necrosis, as indicated by the loss of membrane integrity and morphologic changes. (+)-Cordiaquinone J altered the redox potential of cells by inducing the depletion of reduced GSH intracellular content, the generation of reactive oxygen species and the loss of mitochondrial membrane potential. However, pre-treatment of cells with N-acetyl-l-cysteine abolished most of the observed effects related to (+)-cordiaquinone J treatment, including those involving apoptosis and necrosis induction.
Chemico-biological interactions 12/2009; 183(3):369-79. · 2.46 Impact Factor
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Eufrânio N. da Silva Júnior,
Clara F. de Deus,
Bruno C. Cavalcanti,
Cláudia Pessoa,
Letícia V. Costa-Lotufo, Raquel C. Montenegro,
Manoel O. de Moraes,
Maria do Carmo F. R. Pinto,
Carlos A. de Simone,
Vitor F. Ferreira,
Marilia O. F. Goulart,
Carlos Kleber Z. Andrade,
Antônio V. Pinto
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ABSTRACT: Several 3-arylamino and 3-alkoxy-nor-β-lapachone derivatives were synthesized in moderate to high yields and found to be highly potent against cancer cells SF295 (central nervous system), HCT8 (colon), MDA-MB435 (melanoma), and HL60 (leukemia), with IC50 below 2 μM. The arylamino para-nitro and the 2,4-dimethoxy substituted naphthoquinones showed the best cytoxicity profile, while the ortho-nitro and the 2,4-dimethoxy substituted ones were more selective than doxorubicin and similar to the precursor lapachones, thus emerging as promising new lead compounds in anticancer drug development.
11/2009;
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Eufrânio N da Silva,
Clara F de Deus,
Bruno C Cavalcanti,
Cláudia Pessoa,
Letícia V Costa-Lotufo, Raquel C Montenegro,
Manoel O de Moraes,
Maria do Carmo F R Pinto,
Carlos A de Simone,
Vitor F Ferreira,
Marilia O F Goulart,
Carlos Kleber Z Andrade,
Antônio V Pinto
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ABSTRACT: Several 3-arylamino and 3-alkoxy-nor-beta-lapachone derivatives were synthesized in moderate to high yields and found to be highly potent against cancer cells SF295 (central nervous system), HCT8 (colon), MDA-MB435 (melanoma), and HL60 (leukemia), with IC(50) below 2 microM. The arylamino para-nitro and the 2,4-dimethoxy substituted naphthoquinones showed the best cytoxicity profile, while the ortho-nitro and the 2,4-dimethoxy substituted ones were more selective than doxorubicin and similar to the precursor lapachones, thus emerging as promising new lead compounds in anticancer drug development.
Journal of Medicinal Chemistry 11/2009; 53(1):504-8. · 4.80 Impact Factor
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Ellen C C Silva,
Bruno C Cavalcanti,
Rodrigo C N Amorim,
Jorcilene F Lucena,
Dulcimar S Quadros,
Wanderli P Tadei, Raquel C Montenegro,
Letícia V Costa-Lotufo,
Cláudia Pessoa,
Manoel O Moraes,
Rita C S Nunomura,
Sergio M Nunomura,
Marcia R S Melo,
Valter F de Andrade-Neto,
Luiz Francisco R Silva,
Pedro Paulo R Vieira,
Adrian M Pohlit
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ABSTRACT: In the present study, in vitro techniques were used to investigate a range of biological activities of known natural quassinoids isobrucein B (1) and neosergeolide (2), known semi-synthetic derivative 1,12-diacetylisobrucein B (3), and a new semi-synthetic derivative, 12-acetylneosergeolide (4). These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti, haemolytic activity in mouse erythrocytes and antimalarial activity against the human malaria parasite Plasmodium falciparum. Compounds 1 and 2 exhibited the greatest cytotoxicity against all the tumor cells tested (IC50 = 5-27 microg/L) and against multidrug-resistant P. falciparum K1 strain (IC50 = 1.0-4.0 g/L) and 3 was only cytotoxic toward the leukaemia HL-60 strain (IC50 = 11.8 microg/L). Quassinoids 1 and 2 (LC50 = 3.2-4.4 mg/L) displayed greater lethality than derivative 4 (LC50 = 75.0 mg/L) toward A. aegypti larvae, while derivative 3 was inactive. These results suggest a novel application for these natural quassinoids as larvicides. The toxicity toward A. franciscana could be correlated with the activity in several biological models, a finding that is in agreement with the literature. Importantly, none of the studied compounds exhibited in vitro haemolytic activity, suggesting specificity of the observed cytotoxic effects. This study reveals the biological potential of quassinoids 1 and 2 and to a lesser extent their semi-synthetic derivatives for their in vitro antimalarial and cytotoxic activities.
Memórias do Instituto Oswaldo Cruz 03/2009; 104(1):48-56. · 2.15 Impact Factor
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Dênis Pires de Lima,
Rodrigo Rotta,
Adilson Beatriz,
Maria Rita Marques, Raquel C Montenegro,
Marne C Vasconcellos,
Cláudia Pessoa,
Manoel O de Moraes,
Letícia V Costa-Lotufo,
Alexandra Christine Helena Frankland Sawaya,
Marcos Nogueira Eberlin
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ABSTRACT: This work deals with the preparation of stilbene-based resveratrol analogs by employing the Perkin reaction, aiming at synthesizing potential antitumor lead compounds and evaluating their pharmacological activities. The proliferation inhibitor test against tumor cell lines identified analogs 9 and 11 as the most active among all synthesized derivatives, presenting IC(50) in micromolar range for certain cell lines. For study on the embryonic development, compounds 8 and 9 at the lowest tested concentration (41.7 microM) that inhibited sea urchin egg development, but only after third cleavage were used. Both the compounds inhibited 100% of normal development since first cleavage. These data partially corroborated the results obtained with MTT assay using tumor cell lines. None of the tested compounds revealed hemolytic action in assay with mouse erythrocytes.
European journal of medicinal chemistry 06/2008; 44(2):701-7. · 3.27 Impact Factor
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ABSTRACT: A detailed study on the cytotoxic effects of five known constituents isolated from the flowers and roots of Eupatorium betonicaeforme is reported, including 2,2-dimethyl-6-vinylchroman-4-one (1), 2-senecioyl-4-vinylphenol (2), 6-acetyl-2,2-dimethylchroman-4-one (3), (4E)-8beta-angeloyloxy-9beta,10beta-dihydroxy-1-oxogermacra-4,11(13)-dien-12,6alpha-olide (4), and 3beta-hydroxyicosan-1,5beta-olide (5). The sesquiterpene lactone 4 exhibited the highest cytotoxicity, with IC50 values ranging from 3.9 to 9.9 microM, showing some degree of cell selectivity. The antiproliferative activity of 4 was examined towards HL-60 cells, and found to diminish cell viability in a dose-dependent manner. Moreover, at all concentrations tested, there was a decrease in the number of cells capable of incorporating 5-bromo-2'-deoxyuridine (BrdU), indicating disruption of DNA synthesis. The morphological changes induced by 4 were compatible with apoptotic cell death. This work, thus, corroborates the anticancer potential of Eupatorium secondary metabolites.
Chemistry & Biodiversity 01/2008; 4(12):2835-44. · 1.80 Impact Factor
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Eufrânio N da Silva Júnior,
Maria Cecília B V de Souza,
Antônio V Pinto,
Maria do Carmo F R Pinto,
Marilia O F Goulart,
Francisco W A Barros,
Claudia Pessoa,
Letícia V Costa-Lotufo, Raquel C Montenegro,
Manoel O de Moraes,
Vitor F Ferreira
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ABSTRACT: Several arylamino derivatives of nor-beta-lapachone were synthesized in moderate to high yields and found to show very potent cytotoxicity against six neoplastic cancer cells: SF-295 (central nervous system), HCT-8 (colon), MDAMB-435 (breast), HL-60 (leukaemia), PC-3 (prostate), and B-16 (murine melanoma), with IC(50) below 1 microg/mL. Their cytotoxicities were compared to doxorubicin and with their synthetic precursors, beta-lapachone and nor-beta-lapachone. The activity against a normal murine fibroblast L-929 showed that some of the compounds were selective against cancer cells. The absence of hemolytic activity (EC(50)>200 microg/mL), performed with erythrocyte suspensions, suggests that the cytotoxicity of the compounds was not related to membrane damage of mouse erythrocytes. For comparison purposes, one isomeric compound based on nor-alpha-lapachone was also synthesized and showed lower activity than the related ortho-derivative. The modified arylamino quinones appear as interesting new lead compounds in anti-cancer drug development.
Bioorganic & Medicinal Chemistry 11/2007; 15(22):7035-41. · 2.92 Impact Factor
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ABSTRACT: (1a S*,1b S*,7a S*,8a S*)-4,5-Dimethoxy-1a,7a-dimethyl-1,1a,1b,2,7, 7a,8,8a-octahydrocyclopropa cyclopenta[1,2-b]naphthalene-3,6-dione (1), a new meroterpenoid benzoquinone, and microphyllaquinone (2), a known naphthoquinone, have been isolated from roots of Cordia globosa. Both structure determinations were performed by conventional spectroscopic methods, including inverse detection NMR techniques, and by comparison with data from the literature for related compounds. Compound 1 displayed considerable cytotoxic activity against several cancer cell lines with IC50 values in the range of 1.2 to 5.0 microg/mL. The cytotoxic activity seemed to be related to DNA synthesis inhibition, as revealed by the reduction of 5-bromo-2'-deoxyuridine incorporation, and apoptosis induction, as indicated by the acridine orange/ethidium bromide assay and morphological changes after 24 h of incubation on leukemic cells.
Planta Medica 02/2005; 71(1):54-8. · 2.15 Impact Factor
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ABSTRACT: Eleven known compounds and a new prenylated naphthoquinone, lippsidoquinone (13), were isolated from ethanol extracts of Lippia sidoides. Their structures were established by a combination of 1D and 2D NMR, IR, and EIMS spectral data analysis. The cytotoxic properties of compounds 3−13 were evaluated against HL60, SW1573, and CEM cell lines. Only tectol (6) and lippsidoquinone (13) exhibited significant activity against human leukemia cell lines HL60 and CEM.
05/2001;
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ABSTRACT: From roots of Hyptis martiusii Benth. two tanshinone diterpenes were isolated, the new 7beta-hydroxy-11,14-dioxoabieta-8,12-diene (1) in addition to the known 7alpha-acetoxy-12-hydroxy-11,14-dioxoabieta-8,12-diene (7alpha-acetoxyroyleanone) (2). Structures of 1 and 2 were established by spectroscopic means. The cytotoxic activity against five cancer cell lines was evaluated. Compounds 1 and 2 displayed considerable cytotoxic activity against several cancer cell lines with IC50 values in the range of 3.1 to 11.5 microg/ml and 0.9 to 7.6 microg/ml, respectively. The cytotoxic activity seemed to be related to inhibition of DNA synthesis, as revealed by the reduction of 5-bromo-2'-deoxyuridine incorporation and induction of apoptosis, as indicated by the acridine orange/ethidium bromide assay and morphological changes after 24 h of incubation in leukemic cells.
Zeitschrift fur Naturforschung C 61(3-4):177-83. · 0.77 Impact Factor
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ABSTRACT: Capraria biflora L. (Scrophulariaceae) is a perennial shrub widely distributed in several countries of tropical America. The present work verified the cytotoxic and antioxidant potential of biflorin, an o-naphthoquinone isolated from C. biflora collected in the northeast region of Brazil. The cytotoxicity was tested on three different animal cell models: mouse erythrocytes, sea urchin embryos and tumor cells, while the antioxidant activity was assayed by the thiocyanate method. Biflorin lacked activity on mouse erythrocytes as well as on the development of sea urchin eggs, but strongly inhibited the growth of all five tested tumor cell lines, especially the skin, breast and colon cancer cells with IC50 of 0.40, 0.43 and 0.88 micro/ml for B16, MCF-7 and HCT-8, respectively. Biflorin also showed potent antioxidant activity against autoxidation of oleic acid in a water/alcohol system.
Zeitschrift fur Naturforschung C 60(5-6):394-8. · 0.77 Impact Factor
