Development and validation of HILIC-UHPLC-ELSD methods for determination of sugar alcohols stereoisomers and its application for bioconversion processes of crude glycerin.

The recent increase in the production of crude glycerin through the manufacture of biodiesel has imputed a commercial issue, the excess of this raw material in the market and its constant devaluation, which resulted in the need for new technologies for its use. Crude glycerin can be used in biotechnological processes for the production of high value-added compounds. This study presents novel, simple and fast methods based on ultra-high performance liquid chromatography (UHPLC) using evaporative light scattering detection (ELSD) for simultaneous analysis of ten sugar alcohols with a hydrophilic interaction chromatography (HILIC) column. The selected compounds and their possible stereoisomers have major commercial importance and they can be obtained by biotechnological routes. Under optimized conditions, threitol, erythritol, adonitol, xylitol, arabitol, iditol, sorbitol, mannitol, dulcitol and volemitol can be analyzed simultaneously within 15.0 min. The use of different column temperatures was a key parameter to reach the selectivity during the separation of some stereoisomers. Regression equations revealed a good linear relationship (R > 0.995) over the range from 50.0 to 800.0 ng. Limits of detection (LOD) and quantification (LOQ) ranged from 30.0 to 45.0 ng and 50.0-75.0 ng, respectively. The HILIC-UHPLC-ELSD methods showed good precision with low coefficient of variation (CV%) for the intra- and inter-assays experiments (≤ 5.1%) and high repeatability in terms of retention times for each analyte (≤ 0.5%). The accuracy was confirmed with an average recovery ranging from 92.3 to 107.3%. The developed methods employ an analytical technique more accessible and suitable for routine analyzes and have shown to be suitable for simultaneous analysis of sugar alcohols present in crude bioconverted glycerin samples using different classes of microorganisms.

Determination of catechin diastereomers from the leaves of Byrsonima species using chiral HPLC-PAD-CD.

When catechins are found in plant extracts, they are almost always identified as catechin and/or epicatechin probably due to stereoselectivity of the enzymes involved in the biosynthesis of these substances. However, the lack of reports regarding to ent-catechin as well as ent-epicatechin does not necessarily mean that these compounds have not been produced. In fact, most of the previous reports used chromatographic conditions not suitable for such separation. This article describes a simple and reliable analytical HPLC-PAD-CD method for simultaneous determination of catechin diastereomers both in infusions and extracts from the leaves of Byrsonima species. The direct separation of catechin, ent-catechin, epicatechin, and ent-epicatechin was obtained in normal phase by HPLC-PAD-CD using Chiralcel OD-H as chiral stationary phase and n-hexane/ethanol with 0.1% of TFA as mobile phase.

Isolated flavonoids against mammary tumour cells LM2.

The purpose of the present study was to investigate antitumour and anti-inflammatory activities of flavonoids isolated from Byrsonima crassa, Davilla elliptica and Mouriri pusa. The antitumour activity was measured by the MTT assay in murine mammary tumour cells (LM2) and the IC50 values of the flavonoids tested ranged from (31.5 +/- 2.97) to (203.1 +/- 5.9) microg/ml. The flavonoids 1 (myricetin-3-O-alpha-L-rhamnopyranoside) and 3 (quercetin-3-O-galactopyranoside) from D. elliptica were the most active ones against the tumour cells. The same samples were tested to determine the inhibition of the release of nitric oxide (NO) and of the tumour necrosis factor-alpha (TNF-alpha) in murine macrophages by the Griess and ELISA sandwich assay, respectively. Almost all the samples showed inhibitory activity to the release of NO but not of TNF-alpha. Of all substances tested, flavonoids 2 (quercetin) and 6 (myricetin) may show promising activity in the treatment of murine breast cancer by immunomodulatory and antiproliferative activities.

High-performance liquid chromatographic separation and identification of polyphenolic compounds from the infusion of Davilla elliptica St. Hill.

The isolation of polyphenolic compounds from an infusion of the Brazilian plant Davilla elliptica (Dilleniaceae), used as tea by virtue of its digestive properties, is described. An improved preparative HPLC method was used in order to isolate pure polyphenols from the complex mixture. Liquid-liquid extraction and solid-phase extraction were employed to minimise the interference of polymeric compounds and to provide an enriched fraction of the compounds of interest. The identification of the isolated compounds was performed using analytical HPLC as well as direct injection electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MS/MS). The high flavonoid content suggests that D. elliptica may be a promising source of compounds to produce natural phytomedicines.

Identification of ellagic acid derivatives in methanolic extracts from Qualea species.

The methanolic extract from the barks of the medicinal plant Qualea parviflora (Vochysiaceae) was fractionated by column chromatography over silica gel followed by gel permeation over Sephadex LH-20 to give 3,3'-di-O-methylellagic acid-4-O-beta-D-glucopyranoside (1), 3-O-methylellagic acid-4'-O-alpha-L-rhamnopyranoside (2), 3,3',4-tri-O-methylellagic acid-4'-O-beta-D-glucopyranoside (3), and 3,3'-di-O-methylellagic acid (4), together with triterpenes and saponins. We also performed comparative analyses among this species and Q. grandiflora and Q. multiflora using high-pressure liquid chromatography. The biological assays showed that, when compared to the standard ellagic acid, compounds 1-4 are less cytotoxic but have a lower capacity of stimulating murine peritoneal macrophages to release nitric oxide and tumoural-alpha necrose factor.

Metabolic fingerprinting using direct flow injection electrospray ionization tandem mass spectrometry for the characterization of proanthocyanidins from the barks of Hancornia speciosa.

Direct flow injection electrospray ionization ion trap tandem mass spectrometry (ESI-IT-MS/MS) was used to investigate the polyphenolic compounds present in an infusion from the barks of Hancornia speciosa Gom. (Apocynaceae), a native Brazilian plant popularly known as 'mangabeira', used as a source of nutrition and against gastric disorders. After a simple sample filtration pretreatment the characteristic fingerprint of the infusion was performed in negative ion ESI mode in a few minutes. At low capillary-voltage activation, the deprotonated molecules ([M--H]-) were observed and using collision-induced dissociation the product ion spectra showed the presence of a homologous series of B-type proanthocyanidins, as well as another series containing their respective C-glycosylated derivatives, with a degree of polymerization from 1 up to 6 units of interlinked catechins. Therefore, direct flow injection allowed us to identify the key compounds without preparative isolation of the components.

Mutagenic evaluation and chemical investigation of Byrsonima intermedia A. Juss. leaf extracts.

Byrsonima intermedia is a native species of the cerrado formation (tropical American savannah). In Brazil, this plant has been used for the treatment of fever, in ulcers, as a diuretic, as antiasthmatics and in skin infections. Members of the genus Byrsonima (Malpighiaceae) are employed not only in the folk medicine but also as food to make juice, jellies and liquor. The aim of this work was to evaluate the mutagenic effects of Byrsonima intermedia, common name 'murici'. Phytochemical analysis of methanol extract furnished (+)-catechin, (-)-epicatechin, quercetin-3-O-beta-d-galactopyranoside, methyl gallate, gallic acid, quercetin-3-O-alpha-l-arabinopyranoside, amentoflavone, quercetin, quercetin-3-O-(2''-O-galloyl)-beta-galactopyranoside and quercetin-3-O-(2''-O-galloyl)-alpha-arabinopyranoside. Methanol, hydromethanol and chloroform extracts were evaluated in mutagenic assay with Salmonella typhimurium (Ames test) and mice (Micronucleus test). The methanolic extract presented signs of mutagenic activity for the strains TA98 and TA100 in the Ames assay. Mutagenicity was not observed in vivo.

Application of preparative high-speed counter-current chromatography for the separation of flavonoids from the leaves of Byrsonima crassa Niedenzu (IK).

The methanolic extract of the leaves of the medicinal plant Byrsonima crassa (Malpighiaceae) contain flavonoids with antioxidant activity. They were separated in a preparative scale using high-speed counter-current chromatography. The optimum solvent system used was composed of a mixture of ethyl acetate-n-propanol-water (140:8:80 (v/v/v)) and led to a successful separation between monoglucosilated flavonoids (quercetin-3-O-alpha-L-arabinoside, quercetin-3-O-beta-D-galactoside) and the biflavonoid amentoflavone in only 3.5 h. The purities of quercetin-3-O-alpha-L-arabinoside (95 mg), quercetin-3-O-beta-D-galactoside (16 mg) and the biflavonoid amentoflavone (114 mg) were all isolated at purity over 95%. Identification was performed by 1H NMR, 13C NMR and UV analyses.

Quantification of sex pheromone from Anocentor nitens by gas chromatography-mass spectrometry-selected ion monitoring.

Two highly sensitive and selective methods based on gas chromatography coupled to mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode have been developed for the quantification of 2,6-dichlorophenol (2,6-DCP), a sex pheromone of the tick females of Anocentor nitens. Standard addition method and calibration curve techniques using 5-bromine-4-hydroxy-3-methoxybenzaldehyde (5-BrV) as internal standard (IS) afforded detection limit of 0.1ngml(-1). The calibration curve was linear over the concentration range from 0.5 to 500ngml(-1) for 2,6-DCP. Results show that the concentration range of sex pheromone in the extracts samples was 1.08-10.35ngml(-1). The methods developed provided reliable procedures to determine amounts of 2,6-DCP present in ticks.