[Show abstract][Hide abstract] ABSTRACT: Two new friedelane-type compounds 1 and 2 and five known pentacyclic triterpenes were
isolated from branches of Maytenus robusta. Their structures were identified as 3,16-dioxo-
29-hydroxyfriedelane (1), 3-oxo-16b,29-dihydroxyfriedelane (2), 3-oxofriedelane (3),
3b-friedelinol (4), 3,16-dioxofriedelane (5), 3-oxo-29-hydroxyfriedelane (6), and 3,16-dioxo-
12a-hydroxyfriedelane (7). The structures and the stereochemistry of triterpenes 1 and 2 were
established through infrared (IR), 1D/2D nuclear magnetic resonance (NMR), high-resolution
atmospheric pressure chemical ionization mass spectrometry (HR-APCIMS) spectral data and
powder X-ray diffraction. The in vitro cytotoxic property of triterpenes 1 to 6 on 4T1 murine
breast cancer cells was evaluated. The triterpenes 1 and 2 showed cytotoxic activity against 4T1
cells at a lower concentration.
Full-text · Article · May 2014 · Journal of the Brazilian Chemical Society
[Show abstract][Hide abstract] ABSTRACT: Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single-crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer.
[Show abstract][Hide abstract] ABSTRACT: The effect of 2-pyridinecarboxylic acid (picolinic acid) on trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus was determined in this study. Picolinic acid, at 50¿g mL-1, inhibited epimastigote growth by 99% after 12 days incubation. In addition, trypomastigote motility decreased by 50% after 6h and completely after 24h in the presence of 50 Mg mL-1 picolinic acid. The 50% cytotoxic concentration on HEp-2 cell line was 275 Mg mL-1 after 4 days incubation. Altogether, these results indicate higher toxicity against trypanosomes. The inhibitory effect of picolinic acid on epimastigote growth can be partially reversed by nicotinic acid and L-tryptophan, suggesting a competitive inhibition. Furthermore, two anti-Trypanosoma (Schizotrypanum) cruzi drugs were also evaluated with regard to bat trypanosome growth. Benznidazole, at 50 Mg mL-1, inhibited epimastigote growth by 90% after 12 days incubation. Nifurtimox, at the same concentration, caused 96% growth inhibition after four days incubation. Corroborating a previous study, bat trypanosomes are a good model for screening new trypanocidal compounds. Moreover, they can be used to study many biological processes common to human pathogenic trypanosomatids.
[Show abstract][Hide abstract] ABSTRACT: The chemical investigation of Salacia elliptica allowed to the isolation of 20 constituents: two polyols, one xanthone, a mixture of long chain hydrocarbons, one carboxylic acid, one polymer, two steroidal compounds, one aromatic ester and eleven pentacyclic triterpenes. These triterpenes include 3β-stearyloxy-oleanane, 3β-stearyloxy-ursane, one seco-friedelane, and eight compounds of the friedelane serie. The chemical structure and the relative configuration of a new triterpene 1,3-dioxo-16α-hydroxyfriedelane (15) were established through 1H and 13C NMR including 2D experiments (HMBC, HMQC, COSY and NOESY) and herein reported for the first time.
[Show abstract][Hide abstract] ABSTRACT: The volatile oil from the leaves of E. urograndis was analyzed by GC and GC-MS. It was identified 10 compounds in which, orto-cimene (41.4%) and 1,8-cineol (25.8%) were the main constituents. The induction of deleterious effect to aquatic organisms due to the presence of volatile oil lixiviated from E. urograndis leaves was studied using Daphnia laevis and D. similis as bioindicators. Through the results of toxicological tests it was possible to show that the litterbag of E. urograndis represents a risk factor for the aquatic ecosystem of lakes and rivers that are in the surrounding area of large scale Eucalyptus plantations. The method can be used for monitor the quality of these types of aquatic environments.
[Show abstract][Hide abstract] ABSTRACT: Friedelin (1), 3beta-friedelinol (2), 28-hydroxyfriedelin (3), 16alpha-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16alpha,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl(3) solution, 16alpha-hydroxyfriedelin (4) reacted turning into 3-oxo-16-methylfriedel-16-ene (7). This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl(3) solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY) spectroscopy and mass spectrometry (GC-MS). It is also the first time that all the (13)C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.
[Show abstract][Hide abstract] ABSTRACT: Through instrumental neutron activation analysis (INAA) the elemental chemical composition of Salvinia auriculata and Ouro Preto city public water was determined. Elements Ce, Th, Cr, Hf, Sb, Se, Rb, Fe, Zn, Co, An, La and Br were quantified. High chromium concentration was determined in this plant. But, chromium was determined only in low concentrations in the water. The results indicate the great capacity of this plant to absorb and accumulate inorganic elements. (C) 2007 Published by Elsevier Ltd.
No preview · Article · Jun 2008 · Applied Radiation and Isotopes
[Show abstract][Hide abstract] ABSTRACT: PHYTOCHEMICAL STUDY OF THE DECOCT FROM THE LEAVES OF Maytenus truncata Reissek AND THE EVALUATION OF THE ANTINOCICEPTIVE, ANTIEDEMATOGENIC AND ANTIULCEROGENIC ACTIVITIES OF THE DECOCT EXTRACTS. The present paper describes the phytochemical investigation and biological activities of the chloroform, ethyl acetate and methanol extracts of leaf decocts of M. truncata Reiss (Celastraceae). Our studies afforded two flavonoid glycosides, quercetin-3-O- rhamnopyranosyl-O-glucopyranosyl-O-rhamnopyranosyl-O-galactopyranoside (1) and kampferol-3-O-rhamnopyranosyl-O- glucopyranosyl-O-rhamnopyranosyl-O-galactopyranoside (2) from the methanolic extract and dulcitol (3) from the ethyl acetate extract. Ethyl acetate and methanol extracts exhibited considerable antiulcerogenic and analgesic activities. The results of the phytochemical studies suggest that the healing activity of methanol extracts can be related to the presence of glycosyl flavonoids.
[Show abstract][Hide abstract] ABSTRACT: The triterpene ester (3 beta)-olean-18-en-3-yl stearate (1), together with (3 beta)-urs-12-en-3-yl stearate (2), and (3 beta)-lup-20(29)-en-3-yl stearate (3) were isolated from leaves of Maytenus salicifolia REISSEK (Celastraceae). The structure of 1, a new compound, including its configuration, was established by H-1, C-13, and DEPT-135 NMR data, including 2D experiments (HSQC, HMBC, COSY, and NOESY). The molecular mass (692 Da) was confirmed by gas chromatography coupled with mass spectrometry (CG/MS).
[Show abstract][Hide abstract] ABSTRACT: A pentacyclic triterpene, 3,30-dihydroxy-lup-20(29)-ene, was isolated from the powder extract of Maytenus imbricata. The structure and stereochemistry of the compound were established by spectroscopic techniques and unambiguously determined by single crystal X-ray crystallography. The crystal structure shows one molecule in the asymmetric unit. The crystal packing is stabilized by O–H···O intermolecular hydrogen bonds, which give rise to infinite helical chains along the c unit cell axis. The intra-molecular geometry was analyzed using MOGUL, a knowledge base of molecular geometry derived from the Cambridge Structural Database (CSD).
Full-text · Article · Feb 2006 · Structural Chemistry
[Show abstract][Hide abstract] ABSTRACT: Four lupane pentacyclic triterpenes were isolated from the hexane extract of stems and branches of Maytenus imbricata Mart.ex Reissek: 3-oxolup-20(30)-en-29-al (1), 30-hydroxylup-20(29)-en-3-one (2), (11)-11-hydroxylup-20(29)-en-3-one (3), and (3β)-lup-20(30)-ene-3,29-diol (4). The structural identification of 1–4 was achieved by 1H- and 13C-NMR techniques, including 2D experiments (HSQC, HMBC, and NOESY).
Full-text · Article · May 2005 · Helvetica Chimica Acta
[Show abstract][Hide abstract] ABSTRACT: Four pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20alpha-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.
Preview · Article · Apr 2002 · Revista do Instituto de Medicina Tropical de São Paulo
[Show abstract][Hide abstract] ABSTRACT: Folhas de Austroplenckia populnea (mangabarana, marmelinho do campo) foram submetidos a estudo fitoquímico. Do extrato hexânico foram isolados e identificados três triterpenos pentacíclicos e um sesquiterpeno agarofurânico inédito. Realizou-se testes de atividade antiespermatogência utilizando parte deste extrato. Os resultados mostraram uma redução significativa do número de espermatozóides no epidídimo.
Full-text · Article · Jan 2002 · Revista Brasileira de Farmacognosia