A multi-screening approach for marine-derived fungal metabolites and the isolation of cyclodepsipeptides from Beauveria felina

Extracts obtained from 57 marine-derived fungal strains were analyzed by HPLC-PDA, TLC and ¹H NMR. The analyses showed that the growth conditions affected the chemical profile of crude extracts. Furthermore, the majority of fungal strains which produced either bioactive of chemically distinctive crude extracts have been isolated from sediments or marine algae. The chemical investigation of the antimycobacterial and cytotoxic crude extract obtained from two strains of the fungus Beauveria felina have yielded cyclodepsipeptides related to destruxins. The present approach constitutes a valuable tool for the selection of fungal strains that produce chemically interesting or biologically active secondary metabolites.

Elimination of dyes from aqueous solutions using iron oxides and chitosan as adsorbents: a comparative study

This work investigates the adsorption of Alizarin, Eriochrome Blue Black R and Fluorescein using chitosan, goethite and magnetite as adsorbents. For Alizarin, the best adsorbent is chitosan with a Langmuir parameter of 15.8 mmol dye/g adsorbent. For Eriochrome Blue Black R only 1.94 mmol dye/g chitosan is adsorbed. Langmuir parameters for the Alizarin adsorption on both iron oxides display one or two orders of magnitude lower than for chitosan and two orders of magnitude lower in the case of Eriochrome Blue Black R. Fluorescein does not adsorb in appreciable amounts on chitosan and it presents the lower affinity on the iron oxides.

Recent research data on the removal of pharmaceuticals from sewage treatment plants (STP)

Pharmaceutical compounds have been detected in sewage treatment plant (STP) effluents, surface waters and, less frequently, in groundwater and drinking water, all over the world. Different sources are responsible for their appearance in the aquatic environment, however, it is widely accepted that the main sources of this type of pollutant are STP effluents. The adverse effects of pharmaceuticals in the environment include aquatic toxicity, development of resistance in pathogenic bacteria, genotoxicity and endocrine disruption. Thus, the discharge of these compounds to the environment in STP effluents should be minimized.

Electrodeposition of gold from formaldehyde-sulfite baths: bath stability and deposits characterization

It was investigated Au(I)-sulfite baths containing formaldehyde. As a result, high stability was achieved for baths containing formaldehyde concentration close to 10 mL L-1 with a lifetime superior to 600 days. On the other hand, cyclic voltammograms indicated that the increase of formaldehyde concentration in the bath promotes decreasing of the maximum cathodic current, so that, if the formaldehyde concentration is high, the surface areal concentration of gold will be low. Also, the lowest surface roughness was obtained for 10 mL L-1 of formaldehyde.

Preparative separation and purification of sesquiterpenoids from tussilago farfara l. by high-speed counter-current chromatography

Preparative high-speed counter-current chromatography (HSCCC) was successfully applied for separation and purification of sesquiterpenoids from an extract of Tussilago farfara L. with a two-phase solvent system composed of n-hexane-ethyl acetate- methanol-water (1:0.5:1.1:0.3, v/v/v/v). The separation produced a total of 32 mg of tussilagone, 18 mg of 14-acetoxy-7β-(3'-ethyl cis-crotonoyloxy)-lα-(2'-methyl butyryloxy)-notonipetranone and 21 mg of 7β-(3'-ethyl cis-crotonoyloxy)-lα-(2'- methyl butyryloxy)-3,14-dehydro-Z-notonipetranone from 500 mg of the crude extract in one step separation with the purity of 99.5, 99.4 and 99.1%, respectively, as determined by HPLC. The structures of these compounds were identified by ESI-MS, ¹H-NMR and 13C-NMR.

Kinetics of oxidation of biodiesel from soybean oil mixed with TBHQ: determination of storage time

Synthetic antioxidants are an alternative to prevent or retard the degradation of biofuels made from vegetable oils. In this study, it was evaluated the oxidative stability of B100 soybean oil biodiesel, in the presence of tercbutylhydroquinone (TBHQ). The results showed that the induction period, that precedes the seeding process, was delayed in the presence of the antioxidant. Moreover, the obtained results suggest that the B100 biodiesel containing TBHQ can present a storage time at 25 ºC, three times longer than the estimated time for the pure B100.

Biochemical characterisation of lipase from a new strain of Bacillus sp. ITP-001

Lipases are characterised mainly by catalytic versatility and application in different industrial segments. The aim of this study was to biochemically characterise a lipase from a new strain of Bacillus sp. ITP-001. The isoelectric point and molecular mass were 3.12 and 54 kDa, respectively. The optima lipase activity was 276 U g-1 at pH 7.0 and a temperature of 80 ºC, showing greater stability at pH 5.0 and 37 ºC. Enzymatic activity was stimulated by various ions and pyridine, and inhibited by Cu+ and ethanol. The values of Km and v max were 105.26 mmol and 0.116 mmol min-1 g-1, respectively determined by the Eadie-Scatchard method.

Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae)

This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.

Preparação de derivados do lapachol em meio ácido e em meio básico: uma proposta de experimentos para a disciplina de Química Orgânica Experimental

In this educational paper we describe the extraction of lapachol from its natural source according to acid-base concepts in organic chemistry and the use of its derivatives β-lapachone and hydroxy-hydrolapachol to exemplify intramolecular cyclization, carbocation stability, Michael addition reaction and chromatography. The experiments were performed during three different undergraduate organic chemistry laboratory classes using low cost material, while avoiding color reagents for TLC visualization, as well as small-scale column chromatography to isolate the mixture of lapachol and β-lapachone.

Preparative separation and purification of bufadienolides from ChanSu by high-speed counter-current chromatography combined with preparative HPLC

Eight bufadienolides were successfully isolated and purified from ChanSu by high-speed counter-current chromatography (HSCCC) combined with preparative HPLC (prep-HPLC). First, a stepwise elution mode of HSCCC with the solvent system composed of petroleum ether - ethyl acetate - methanol - water (4:6:4:6, 4:6:5:5, v/v) was employed and four bufadienolides, two partially purified fractions were obtained from 200 mg of crude extract. The partially purified fractions III and VI were then further separated by prep-HPLC, respectively, and another four bufadienolides were recovered. Their structures were confirmed by ESI-MS and ¹H-NMR spectra.

Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-β-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-β-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR).

Phytotoxic effects of metabolites from Alternaria euphorbiicola against its host plant Euphorbia heterophylla

A bioassay-guided fractionation of culture filtrates of the fungus Alternaria euphorbiicola, a pathogen of the weed Euphorbia heterophylla, led to the isolation of anhydromevalonolactone (1), tyrosol (2), (R)-( - )-mevalonolactone (3), and cycloglycylproline (4). When tested on the punctured leaves of the host plant, these compounds produced bleached lesions with dark brown margins at concentrations as low as 80 µM. When tested on the leaves of other relevant weeds, only cycloglycylproline showed selective activity against E. heterophylla. This is the first report on the isolation of phytotoxins from A. euphorbiicola and on the phytotoxicity of anhydromevalonolactone, (R)-( - )-mevalonolactone, and cycloglycylproline.

Chemical composition of volatiles from male and female specimens of Baccharis trimera collected in two distant regions of southern brazil: a comparative study using chemometrics

GC/MS/FID analyses of volatile compounds from cladodes and inflorescences from male and female specimens of Baccharis trimera (Less.) DC. collected in the states of Paraná and Santa Catarina, Brazil, showed that carquejyl acetate was the primary volatile component (38% to 73%), while carquejol and ledol were identified in lower concentrations. Data were subjected to hierarchical cluster analysis and principal component analysis, which confirmed that the chemical compositions of all samples were similar. The results presented here highlight the occurrence of the same chemotype of B. trimera in three southern states of Brazil.

Biosorption and removal of chromium from water by using moringa seed cake (Moringa oleifera Lam.)

This study evaluated the adsorption capacity of chromium from contaminated aqueous solutions by using Moringa oleifera Lam. seeds. Parameters such as solution pH, adsorbent mass, contact time between solution and adsorbent, isotherms, thermodynamic, kinetics, and desorption were evaluated. The maximum adsorption capacity (Qm) calculated to be 3.191 mg g-1 for the biosorbent. Activated carbon was used for comparison purposes in addition to the biosorbent. The best fit was obtained by the Langmuir model for both adsorbents. The average desorption value indicated that both the biosorbent and activated carbon have a strong interaction with the metal. The results showed that the biosorbent has advantages owing to its low cost and efficiency in Cr3+ removal from contaminated waters.

Ligandless cloud point extraction of trace amounts of palladium and rhodium in road dust samples using Span 80 prior to their determination by flame atomic absorption spectrometry

In this study, a procedure is developed for cloud point extraction of Pd(II) and Rh(III) ions in aqueous solution using Span 80 (non-ionic surfactant) prior to their determination by flame atomic absorption spectroscopy. This method is based on the extraction of Pd(II) and Rh(III) ions at a pH of 10 using Span 80 with no chelating agent. We investigated the effect of various parameters on the recovery of the analyte ions, including pH, equilibration temperature and time, concentration of Span 80, and ionic strength. Under the best experimental conditions, the limits of detection based on 3Sb for Pd(II) and Rh(III) ions were 1.3 and 1.2 ng mL-1, respectively. Seven replicate determinations of a mixture of 0.5 µg mL-1 palladium and rhodium ions gave a mean absorbance of 0.058 and 0.053 with relative standard deviations of 1.8 and 1.6%, respectively. The developed method was successfully applied to the extraction and determination of the palladium and rhodium ions in road dust and standard samples and satisfactory results were obtained.