A simplified procedure for determination of clofentezine residues in fruits by liquid chromatography with UV detection

A rapid and sensitive method is described for the determination of clofentezine residues in apple, papaya, mango and orange. The procedure is based on the extraction of the sample with a hexane:ethyl acetate mixture (1:1, v/v) and liquid chromatographic analysis using UV detection. Mean recoveries from 4 replicates of fortified fruit samples ranged from 81% to 96%, with coefficients of variation from 8.9% to 12.5%. The detection and quantification limits of the method were of 0.05 and 0.1 mg kg-1, respectively.

In vitro propagation of Maytenus ilicifolia (Celastraceae) as potential source for antitumoral and antioxidant quinomethide triterpenes production. A rapid quantitative method for their analysis by reverse-phase high-performance liquid chromatography

Cell culture of Maytenus ilicifolia were established in order to produce and to quantify the antitumoral and antioxidant quinonemethide triterpenes. In vitro calli were induced from leaf explants of native plants and cultured in semi-solid medium under controlled conditions of humidity, temperature and photoperiod. The quinonemethide triterpenes showed maximum accumulation in the logarithmic phase growth of the cell culture. A rapid, sensitive and reliable reverse-phase HPLC method was used for quantitative determination of the antitumoral and antioxidant quinonemethide triterpenes, 22β-hydroxymaytenin and maytenin in callus of Maytenus ilicifolia. Well resolved peaks with good detection response and linearity in the range 1.0 - 100 μg/mL were obtained. This quantitative work was performed by an external standard method.

Determination of flutamide in tablets by high-performance liquid chromatography

Flutamide is a potent antiandrogen used for the treatment of prostatic cancer. A simple, sensitive and accurate high-performance liquid Chromatographic (HPLC) method is presented for quantitative determination of flutamide in tablets, using a reversed-phase technique and UV detection at 240 nm. The isocratic elution was used to quantify the analyte. The samples were chromatographed on Luna-C18 column and the mobile phase was 0.05 M phosphate buffer pH 4.0 - acetonitrile (50:50, v/v). The method was linear between 2.9 - 11.6 mg L -1. Over the tested concentration range the intra-day relative standard deviation for replicate analysis in tablets ranged from 0.44 to 0.78%. It was also found that the excipients in the commercial tablets did not interfere with the method.

A comparison of mycolic acid analysis for nontuberculous mycobacteria identification by thin-layer chromatography and molecular methods

The development of fast, inexpensive, and reliable tests to identify nontuberculous mycobacteria (NTM) is needed. Studies have indicated that the conventional identification procedures, including biochemical assays, are imprecise. This study evaluated a proposed alternative identification method in which 83 NTM isolates, previously identified by conventional biochemical testing and in-house M. avium IS1245-PCR amplification, were submitted to the following tests: thin-layer chromatography (TLC) of mycolic acids and PCR-restriction enzyme analysis of hsp65 (PRA). High-performance liquid chromatography (HPLC) analysis of mycolic acids and Southern blot analysis for M. avium IS1245 were performed on the strains that evidenced discrepancies on either of the above tests. Sixty-eight out of 83 (82%) isolates were concordantly identified by the presence of IS1245 and PRA and by TLC mycolic acid analysis. Discrepant results were found between the phenotypic and molecular tests in 12/83 (14.4%) isolates. Most of these strains were isolated from non-sterile body sites and were most probably colonizing in the host tissue. While TLC patterns suggested the presence of polymycobacterial infection in 3/83 (3.6%) cultures, this was the case in only one HPLC-tested culture and in none of those tested by PRA. The results of this study indicated that, as a phenotypic identification procedure, TLC mycolic acid determination could be considered a relatively simple and cost-effective method for routine screening of NTM isolates in mycobacteriology laboratory practice with a potential for use in developing countries. Further positive evidence was that this method demonstrated general agreement on MAC and M. simiae identification, including in the mixed cultures that predominated in the isolates of the disseminated infections in the AIDS patients under study. In view of the fact that the same treatment regimen is recommended for infections caused by these two species, TLC mycolic acid analysis may be a useful identification tool wherever molecular methods are unaffordable.

Fast preparative separation of flavones from capitula of Eriocaulon ligulatum (Vell.) L.B.Smith (Eriocaulaceae) by High-speed countercurrent chromatography (HSCCC)

High-speed countercurrent chromatography (HSCCC) is a leading method for the fast separation of natural products from plants. It was used for the preparative isolation of two flavone monoglucosides present in the capitula of Eriocaulon ligulatum (Veil.) L.B.Smith (Eriocaulaceae). This species, known locally as botão-dourado, is exported to Europe, Japan and North America as an ornamental species, constituting an important source of income for the local population of Minas Gerais State, Brazil. The solvent system, optimized in tests prior to the HSCCC run, consisted of the two phases of the mixture ethyl acetate: n-propanol: water (140:8:80, v/v/v), which led to the successful separation of 6-methoxyluteolin-7-O-β-D-allopyranoside and 6-methoxyapigenin-7-O-β-D-allopyranoside in only 3 hours. The two flavonoids were identified by NMR (1-D and 2-D) and ESI-MS, comparing their spectra with published data.

High-performance liquid chromatography determination of praziquantel in tablets and raw materials

A specific and sensitive high-performance liquid chromatographic method was developed for the assay of praziquantel in raw materials and tablets. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay in the wavelenght selected. The method validation yielded good results and included the range, linearity, precision, accuracy, specificity and recovery.

Isolation of lignans glycosides from Alibertia sessilis (Vell.) K. Schum. (Rubiaceae) by preparative high-performance liquid chromatography

Enantiomeric aglycone lignans contained in a mixture were separated from a fraction of the extract of the stems of Alibertia sessilis (Vell.) K. Schum. (Rubiaceae) by preparative high-performance liquid chromatography. An efficient and fast separation can be achieved with methanol-water (30:70, v/v). Their structures were identified as (+)-lyoniresinol 3α-O-β-glucopyranoside and (-)-lyoniresinol 3α-O-β-glucopyranoside, being reported for the first time in Rubiaceae.

Separation of the toxic zierin from Zollernia ilicifolia by high speed countercurrent chromatography

Preliminary pharmacological assays of the 70% methanol extract from the leaves of the Brazilian medicinal plant Zollernia ilicifolia Vog. (Fabaceae) showed analgesic and antiulcerogenic effects. Previous analyses have shown that this extract contains, besides flavonoid glycosides and saponins, a toxic cyanogenic glycoside. Flavonoids and saponins are compounds reported in literature with antiulcerogenic activity. In this work, we developed a methodology to separate the cyanogenic glycoside from these compounds in order to obtain enough amount of material to perform pharmacological assays. The cyanogenic glycoside zierin (2S)-β-D-glucopyranosyloxy-(3-hydroxy-phenyl)- acetonitrile was separated from the other components by high speed countercurrent chromatography (HSCCC). The solvent system used was composed of chloroform-methanol-n-propanol-water (5:6:1:4, v/v/v/v). This technique led to the separation of zierin from the possible active compounds of Zollernia ilicifolia.

Determination of disease biomarkers in Eucalyptus by comprehensive two-dimensional gas chromatography and multivariate data analysis

In this paper is reported the use of the chromatographic profiles of volatiles to determine disease markers in plants - in this case, leaves of Eucalyptus globulus contaminated by the necrotroph fungus Teratosphaeria nubilosa. The volatile fraction was isolated by headspace solid phase microextraction (HS-SPME) and analyzed by comprehensive two-dimensional gas chromatography-fast quadrupole mass spectrometry (GC. ×. GC-qMS). For the correlation between the metabolic profile described by the chromatograms and the presence of the infection, unfolded-partial least squares discriminant analysis (U-PLS-DA) with orthogonal signal correction (OSC) were employed. The proposed method was checked to be independent of factors such as the age of the harvested plants. The manipulation of the mathematical model obtained also resulted in graphic representations similar to real chromatograms, which allowed the tentative identification of more than 40 compounds potentially useful as disease biomarkers for this plant/pathogen pair. The proposed methodology can be considered as highly reliable, since the diagnosis is based on the whole chromatographic profile rather than in the detection of a single analyte. © 2013 Elsevier B.V..

Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by flow injection analysis - Electrospray ionization ion trap tandem mass spectrometry and liquid chromatography/electrospray ionization mass spectrometry

The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

Dereplication of phenolic derivatives of qualea grandiflora and qualea cordata (vochysiaceae) using liquid chromatography coupled with ESI-QToF-MS/MS

A rational and selective method using on-line high-performance liquid chromatography (HPLC) coupled with electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QToF-MS/MS) was established for the dereplication of phenolic derivatives from Qualea grandiflora and Qualea cordata. The selection of the extracts was based on the antioxidant capacity measured by in vitro DPPH assay. The HPLC-ESI-QToF-MS/MS analysis was conducted by on-flow detection, using high-resolution mass/ratio ions as well as collision induced MS/MS experiments for selected protonated ions. The dereplication of the EtOAc fraction from the hydro alcohol extract from the stem bark of Q. grandiflora allowed the detection of the flavonoids: 3',4',5',5,6,7-hexahydroxy- 8 methylflavanone, 8-methyl-naringenine and 3',7-dimethoxy-8 methyl-4',5,7- trihydroxyflavanone, as well as a benzophenone derivatives: bis(4,6-dimethoxy-2- hydroxy-3-methylphenyl)- metanone, 3',4'-dimethoxy-8-methyl-5,6,7 trihydroxyflavanone, 7-methoxy-6-methyl- 3',4',5 trihydroxyflavanone, 6,8-dimethyl-3' methoxy-4',5,7 trihydroxyflavanone and 3',5'-dimethoxy-6,8- dimethyl-4',5,7 trihydroxyflavanone were detected in the EtOAc fraction from the hydro-alcohol extract from the leaves of Q. cordata. © 2013 Sociedade Brasileira de Química.

Matrix Effects on Water Analysis for Alkylphenols Using Solid Phase Extraction Gas Chromatography-Mass Spectrometry

Gas chromatography with mass spectrometry is frequently used for the quantification of many classes of substances, including alkylphenols. Alkylphenol polyethoxylates are nonionic surfactants used in a wide variety of industrial and consumer applications. Alkylphenol polyethoxylates can degrade to alkylphenols, which are endocrine disruptors. In analytical validation procedures, the most common parameters studied are the detection and quantification limits, linearity, and recovery; however, the matrix effects are sometimes neglected. Although some investigators have evaluated matrix effects, there is no consensus on how to evaluate them during method validation. In this study, the matrix effects of alkylphenol polyethoxylates (nonylphenol monoethoxylate, nonylphenol diethoxylate, octylphenol monoethoxylate, octylphenol diethoxylate) and alkylphenols (nonylphenol and octylphenol) were studied using solid phase extraction and gas chromatography-mass spectrometry analysis. For alkylphenol polyethoxylates, the matrix effects ranged from 16 to 4692%, whereas for alkylphenols (nonylphenol and octylphenol), the effects were insignificant. Therefore, constructing an analytical curve in the matrix for alkylphenol polyethoxylates is essential. © 2013 Copyright Taylor and Francis Group, LLC.

Continuous vs. segmented second-dimension system gradients for comprehensive two-dimensional liquid chromatography of sugarcane (Saccharum spp.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comprehensive two-dimensional gas chromatography combined to multivariate data analysis for detection of disease-resistant clones of Eucalyptus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)