RESUMO
Bioassay-guided fractionation of a methanol extract of Albizia subdimidiata using the engineered yeast strains 1138, 1140, 1353, and Sc7 of Saccharomyces cerevisiae as the bioassay tool resulted in the isolation of the two active saponins 1 and 2; one of these, albiziatrioside A (1), is described for the first time. The structures of 1 and 2 were established on the basis of HRMS, 1D and 2D NMR spectral data, and GC--MS analysis of the sugar units. Both isolated compounds showed significant cytotoxicity against the A2780 cell line.
Assuntos
Rosales/química , Saponinas/isolamento & purificação , Configuração de Carboidratos , Sequência de Carboidratos , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Saponinas/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , SurinameRESUMO
Bioactivity-directed fractionation of an EtOAc extract from the leaves of Miconia lepidota afforded the two benzoquinones 2-methoxy-6-heptyl-1,4-benzoquinone (1) and 2-methoxy-6-pentyl-1,4-benzoquinone (primin) (2). This is the first reported isolation of 1. Both quinones 1 and 2 exhibited activity toward mutant yeast strains based on Saccharomyces cerevisiae, indicative of their cytotoxicity and potential anticancer activity. A number of previously synthesized and new analogues were prepared and tested in the same strains. Compounds 1, 2, 2-methoxy-6-butyl-1,4-benzoquinone (5), and 2-methoxy-6-decyl-1,4-benzoquinone (6) were tested in two cytotoxicity assays. In the M109 tumor cell lines, quinones 1, 2, and 6 had an IC(50) value of 10 microg/mL. In the A2780 cell line, compounds 1, 2 and 5 had IC(50) values of 7.9, 2.9, and 3.2 microg/mL, respectively.
Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Benzoquinonas/química , Benzoquinonas/farmacologia , Plantas Medicinais/química , Antineoplásicos Fitogênicos/isolamento & purificação , Benzoquinonas/isolamento & purificação , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Espectroscopia de Ressonância Magnética , Extratos Vegetais/química , Espectrometria de Massas por Ionização por Electrospray , Relação Estrutura-Atividade , Suriname , Células Tumorais Cultivadas , Leveduras/efeitos dos fármacosRESUMO
Bioassay-guided fractionation of the MeOH extract of Swartzia schomburgkii using the engineered yeast strains 1138, 1140, and 1353 as the bioassay tool resulted in the isolation of five active (2, 4-7) and three inactive (1, 3, 8) saponins. Saponins 4 and 6 are previously unreported. The structures of all of the saponins were established based on 1D and 2D NMR spectral analysis, on acid and alkaline hydrolysis followed by TLC and GC-MS, and by comparison with literature data for known compounds. Three of the isolated compounds (4-6) showed weak cytotoxicity against the M-109 cell line.
Assuntos
Plantas Medicinais/química , Saponinas/análise , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Hidrólise , Espectroscopia de Ressonância Magnética , Saponinas/farmacologia , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Suriname , Células Tumorais CultivadasRESUMO
Continuation of a previous study on Renealmia alpinia resulted in the isolation of the new labdane diterpenoid 3, together with two known diterpenoids. The structure of the new diterpenoid was determined by a combination of NMR techniques and HRFABMS.
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Diterpenos/isolamento & purificação , Zingiberales/química , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrometria de Massas de Bombardeamento Rápido de Átomos , SurinameRESUMO
Continuation of a previous study on Renealmia alpinia resulted in the isolation of the new labdane diterpenoid 3, together with two known diterpenoids. The structure of the new diterpenoid was determined by a combination of NMR techniques and HRFABMS. (AU)
Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Diterpenos/isolamento & purificação , Zingiberales/química , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrometria de Massas de Bombardeamento Rápido de Átomos , SurinameRESUMO
Bioassay-guided fractionation of an extract of a mixture of Microphilis guyanensis and Genipa americanacollected in the rainforest of Suriname yielded the known alkaloid cryptolepine (2) as the major active compound in a yeast bioassay for potential DNA-damaging agents; the same compound was later reisolated from M. guyanensis. The structure of cryptolepine was identified unambiguously by spectral data and by its total synthesis. Several cryptolepine derivatives (3-29, 32-41) were synthesized based on modifications of the C-2, N-5, N-10, and C-11 positions. Two cryptolepine dimers (30, 31) were also prepared. The structure modifications did not result in compounds with a higher potency than the parent compound cryptolepine in the yeast assay system, although some derivatives did show significant activity. Selected compounds (6, 7, 17, 22, 23, 26, and 27) were also tested for cytotoxicity in mammalian cell culture, and two compounds showed significant cytotoxic activity.
Assuntos
Alcaloides/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Indóis , Plantas Medicinais/química , Quinolinas , Alcaloides/síntese química , Alcaloides/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Dano ao DNA , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Alcaloides Indólicos , Testes de Sensibilidade Microbiana , Saccharomyces cerevisiae/efeitos dos fármacos , Suriname , Células Tumorais CultivadasRESUMO
Bioassay-guided fractionation of the MeOH extract of Eclipta alba using three yeast strains (1138, 1140, and 1353) resulted in the isolation of eight bioactive steroidal alkaloids (1-8), six of which are reported for the first time from nature. The major alkaloid was identified as (20S)(25S)-22,26-imino-cholesta-5,22(N)-dien-3beta-ol (verazine, 3), while the new alkaloids were identified as 20-epi-3-dehydroxy-3-oxo-5,6-dihydro-4,5-dehydroverazine (1), ecliptalbine [(20R)-20-pyridyl-cholesta-5-ene-3beta,23-diol] (4), (20R)-4beta-hydroxyverazine (5), 4beta-hydroxyverazine (6), (20R)-25beta-hydroxyverazine (7), and 25beta-hydroxyverazine (8). Ecliptalbine (4), in which the 22,26-imino ring of verazine was replaced by a 3-hydroxypyridine moiety, had comparable bioactivity to verazine in these assays, while a second alkaloid (8) showed good activity against Candida albicans. All the alkaloids showed weak cytotoxicity against the M-109 cell line.
Assuntos
Alcaloides/farmacologia , Asteraceae/química , Dano ao DNA , DNA/efeitos dos fármacos , Fitosteróis/farmacologia , Plantas Medicinais/química , Alcaloides/isolamento & purificação , Candida albicans/efeitos dos fármacos , Linhagem Celular , Índia , Espectroscopia de Ressonância Magnética , Fitosteróis/isolamento & purificação , Saccharomyces cerevisiae/efeitos dos fármacos , SurinameRESUMO
Bioassay-guided fractionation of Eschweilera coriacea collected in the lowland wet forest of Suriname yielded the new but only weakly active ellagic acid derivative eschweilenol A (1) and the two new but inactive ellagic acid derivatives eschweilenol B (2) and eschweilenol C (3). The four known compounds, sucrose, ellagic acid, 3-O-galloylepigallocatechin, and epigallocatechin, were also isolated. The structures of the three new compounds were determined by spectrometric methods, primarily from the HMQC, HMBC, NOESY, and ROESY NMR techniques, and chemical methods, including methylation and triethylsilylation. The location of a hydroxyl group in one ellagic acid derivative was determined by a new technique involving an NOE correlation of the protons of a triethylsilyl derivative with a proton on a neighboring aromatic ring.
Assuntos
Ácido Elágico/análogos & derivados , Epiderme Vegetal/química , Plantas Medicinais/química , Antifúngicos/farmacologia , Sequência de Carboidratos , Cromatografia em Camada Fina , Ácido Elágico/isolamento & purificação , Ácido Elágico/farmacologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Suriname , Leveduras/efeitos dos fármacosRESUMO
The preservation of tropical rainforests is an important goal both for the intrinsic value of their cultural and biological diversity as well as for the well-being of the peoples who make these forests their home. In addition, tropical forests are potential sources of new pharmaceutical products that can only be found by chemical prospecting in Nature's genetically encoded combinatorial library. As part of an effort to integrate biodiversity conservation and drug discovery with economic development, we have initiated a collaborative program to discover potential pharmaceuticals in the rainforest of Suriname. The plant Renealmia alpinia (Zingiberaceae) was selected for investigation based on its ethnomedical use as a febrifuge, but testing in the yeast Sc-7 assay gave a positive response, indicative of cytotoxic activity. Using this bioassay, the two new labdane diterpense, 11-hydroxy-8(17),12(E)-labdadien-15,-16-dial 11,15-hemiacetal (1) and 16-oxo-8(17),12(E)-labdadien-15-oic acid (2), and the known diterpene, 8(17),12(E)-labdadien-15,16-dial (3), have been isolated. Their structures were elucidated by 1D and 2D NMR techniques (DEPT, COSY, HETCOR, HMBC, and NOESY) and IR, UV, and MS spectra, and the absolute stereochemistry of 1 was established by CD spectroscopy and by the formation and NMR analysis of alpha-methoxyphenylacetyl esters. The hemiacetal 1 was cytotoxic to M109 cells, with an IC50 value of 2.6 micrograms/mL.
Assuntos
Diterpenos/isolamento & purificação , Plantas Medicinais/química , Animais , Diterpenos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Extratos Vegetais/química , Saccharomyces cerevisiae/efeitos dos fármacos , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Suriname , Células Tumorais CultivadasRESUMO
Bioassay-guided fractionation of the EtOAc extract of both Allamanda cathartica and Himatanthus fallax (Apocynaceae) using the Sc-7 yeast strain resulted in the isolation of the weakly cytotoxic isoplumericin and plumericin. In addition, the new lignan 7(R)-methoxy-8-epi-matairesional and three known compounds, plumieride, matairesinol, and pinoresinol, were isolated from H. fallax.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Furanos/isolamento & purificação , Lignanas/isolamento & purificação , Plantas Medicinais/química , Compostos de Espiro/isolamento & purificação , Animais , Antineoplásicos Fitogênicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Furanos/farmacologia , Lignanas/farmacologia , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Saccharomyces cerevisiae/efeitos dos fármacos , Compostos de Espiro/farmacologia , Suriname , Células Tumorais CultivadasRESUMO
Between March 1986 and March 1988, 47 consecutive patients, whose paraquat intoxication was confirmed by urine testing, were enrolled in a prospective study on the treatment of paraquat poisoning. Fourteen received a standard treatment regimen consisting of fluid replacement and oral absorbents, and 33 received high-dose cyclophosphamide and dexamethasone, in addition to standard therapy. The case fatality rate in both treatment groups (63 and 61%) was similar. In addition, all 26 patients whose paraquat serum concentrations were measured and who had a probability of survival of less than 65% according the survival curve of Hart et al. died, regardless of therapy. These included four in the cyclophosphamide/dexamethasone group and two in the standard treatment group who had prior survival probabilities between 50 and 65%. This indicated that the cut-off curve relating mortality and paraquat serum concentrations was similar in both treatment groups. High-dose cyclophosphamide/dexamethasone treatment is unlikely to improve the prognosis of paraquat poisoning.
Assuntos
Ciclofosfamida/administração & dosagem , Dexametasona/administração & dosagem , Paraquat/intoxicação , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paraquat/sangue , Intoxicação/tratamento farmacológico , Estudos ProspectivosRESUMO
Hematological and hemoglobin composition data are presented for 14 members of a Surinam family (and for 1 unrelated subject) with either a beta-thalassemia heterozygosity [5 with the -29 (A----G) beta + mutation and 5 with the IVS II-849 (A----G) beta(0) mutation] or a compound heterozygosity (the 5 remaining patients). Identification of the mutation was by hybridization of amplified DNA with 32P-labelled synthetic oligonucleotides. The data indicate distinct differences between the two groups of heterozygotes, mainly in degree of microcytosis and hypochromia, in Hb A2 level, and in the level of G gamma (high in the -29 heterozygotes and low in the IVS II-849 heterozygotes). The 5 compound heterozygotes had a thalassemia intermedia with high Hb F levels (high G gamma), elevated Hb A2, and Hb A levels comparable to those seen in patients with a homozygosity for the -29 mutation or with the combination of this beta(+)-thalassemia and Hb S. An alpha-thalassemia-2 heterozygosity (-3.7 kb deletion) was present in 2 patients. Their hematological data were improved over those for the patients with four alpha globin genes; one was the mother of two sets of twins. The high G gamma value in the Hb F of the compound heterozygotes suggests that the high Hb F production in the condition is mainly directed by the chromosome with the -29 (A----G) mutation.
Assuntos
Talassemia/genética , Adulto , Idoso , Alelos , Criança , Pré-Escolar , Feminino , Testes Hematológicos , Hemoglobinas/análise , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , SurinameRESUMO
Three different hemoglobinopathies, i.e. Hb S, Hb Chad [alpha 23 (B4)Glu----Lys], and alpha-thalassemia-2 (-3.7) have been observed in eight members of a family from Surinam. The proposita had all three abnormalities, while her mother and four of her half-brothers had Hb Chad together with an alpha-thalassemia-2 heterozygosity or homozygosity. Gene mapping and dot-blot analysis of amplified DNA identified a G----A mutation in codon 23 of the alpha 2 alpha 1 hybrid gene resulting in the Glu----Lys substitution. The quantity of the alpha-Chad chain averaged 31.5% in its carriers with an additional alpha-thalassemia-2 heterozygosity [-alpha Chad(-3.7 kb)/alpha alpha], and 43% in the two carriers with an additional alpha-thalassemia-2 homozygosity [-alpha Chad (-3.7 kb)/-alpha (3.7 kb)]. These quantities are considerably higher than those reported for families from Chad, China, and Japan; the low levels of 14.5-24% Hb Chad in members of previously reported cases suggest a mutation on a chromosome with two alpha-globin genes [alpha alpha Chad/alpha alpha or alpha Chad alpha/alpha alpha].