In vitro Antioxidant and Enzymatic Approaches to Evaluate Neuroprotector Potential of Blechnum Extracts without Cytotoxicity to Human Stem Cells.

BACKGROUND: Investigation of selected plant extracts on multi-targets related to neurodegeneration, such as monoamine oxidases (MAO), cholinesterase enzymes, and antioxidant activities (AOA) is a useful tool for identification of new scaffolds. OBJECTIVE: This work investigated biological effects of three Blechnum methanol extracts from Brazil and chemical profile of the most active sample. MATERIALS AND METHODS: AOA included scavenging of hydroxyl and nitric oxide radicals, also lipid peroxidation inhibition. Enzymatic modulation of Blechnum binervatum, Blechnum brasiliense, and Blechnum occidentale extracts on MAO and cholinesterases was conducted. Moreover, total phenol content was performed with all samples, and high-performance liquid chromatography-diode array detection mass spectrometry HPLC-DAD-MS analysis was carried out with B. brasiliense. Possible toxic effects were evaluated on Wistar rats polymorphonuclear cells (PMN) and human stem cells. RESULTS: B. brasiliense extract presented the highest phenolic amount (9.25 g gallic acid equivalent/100 g extract) and lowest IC50 values (112.3 ± 2.61 and 176.1 ± 1.19 µg/mL) against hydroxyl radicals and on lipid peroxidation, respectively, showing strong AO effects. On nitric oxide assay and cholinesterase inhibition, all extracts were considered inactive. MAO-A selective action was evidenced, being B. brasiliense powerful against this enzyme (IC50: 72.7 µg/mL), followed by B. occidentale and B. binervatum (IC50: 130.85 and 165.2 µg/mL). No cytotoxic effects were observed on PMN and human stem cells treated with Blechnum extracts. HPLC-DAD-MS analysis of B. brasiliense allowed the identification of chlorogenic and rosmarinic acids. CONCLUSION: Our results especially highlight B. brasiliense, with pronounced phenols content and strong effects on selected targets related to neurodegeneration, being characterized as a natural safe source of bioactive hydroxycinnamic acids. SUMMARY: Blechnum crude extracts showed high phenolic amounts and valuable IC50 values on targets related with neurodegenerative disordersBlechnum brasiliense was the most active sample, with strong radical scavenging and lipid peroxidation inhibition, also with monoamine oxidases: A selective modulationNo cytotoxic effects were observed on polymorphonuclear cells rat cells and human stem cells treated with Blechnum extractsHigh-performance liquid chromatography-diode array detection-mass spectrometry analysis of Blechnum brasiliense allowed the identification of hydroxycinnamic derivatives: Chlorogenic and rosmarinic acids. Abbreviations used: IC50: half maximal inhibitory concentration; MAO: monoamine oxidase; MAO-A: monoamine oxidase isoform A; MAO-B: monoamine oxidase isoform B; HO•: hydroxyl radical.

Reversed-phase-liquid chromatography method for separation and quantification of gallic acid from hydroalcoholic extracts of Qualea grandiflora and Qualea parviflora.

BACKGROUND: Qualea parviflora and Qualea grandiflora (Vochysiaceae), commonly known in Brazil as "pau-terra" and "pau-terrinha," respectively, have been widely used in the treatment of ulcer and gastritis. These therapeutic effects are attributed to various compounds present in the plants, including phenolic compounds such as gallic acid, due to their important antioxidant activity. OBJECTIVE: The aim of the present study was to validate a high performance liquid chromatography with diode array detection (HPLC-DAD) method for the quantitative determination of gallic acid in the stem bark of Q. parviflora and Q. grandiflora hydroalcoholic extracts. MATERIALS AND METHODS: The chromatography analysis was successfully achieved on a Dionex column, Acclaim(®) 120 (250 mm × 4.60 mm, 5 µm) with a gradient elution of water and methanol at a flow rate of 0.8 mL/min and ultraviolet detection at 280 nm. RESULTS: The validation data, including linearity, precision, specificity, accuracy and robustness of this method demonstrated good reliability and sensitivity. CONCLUSION: The method is able to quantify gallic acid in the stem bark of both species. What is more, the chromatographic peaks showed good resolution and there are also the advantages of easy sample preparation and a short time between each injection.

Liquid chromatography with diode array detection and multivariate curve resolution for the selective and sensitive quantification of estrogens in natural waters.

Following the green analytical chemistry principles, an efficient strategy involving second-order data provided by liquid chromatography (LC) with diode array detection (DAD) was applied for the simultaneous determination of estriol, 17ß-estradiol, 17α-ethinylestradiol and estrone in natural water samples. After a simple pre-concentration step, LC-DAD matrix data were rapidly obtained (in less than 5 min) with a chromatographic system operating isocratically. Applying a second-order calibration algorithm based on multivariate curve resolution with alternating least-squares (MCR-ALS), successful resolution was achieved in the presence of sample constituents that strongly coelute with the analytes. The flexibility of this multivariate model allowed the quantification of the four estrogens in tap, mineral, underground and river water samples. Limits of detection in the range between 3 and 13 ng L(-1), and relative prediction errors from 2 to 11% were achieved.

Determination of five pesticides in juice, fruit and vegetable samples by means of liquid chromatography combined with multivariate curve resolution.

The aim of this work was to quantify five commonly used pesticides (propoxur, carbaryl, carbendazim, thiabendazole and fuberidazole) in real samples as: tomato, orange juice, grapefruit juice, lemon and tangerine. The method used for the determination of these analytes in the complex matrices was high-performance liquid chromatography with diode array detection. In order to work under isocratic conditions and to complete each run in less than 10 min, the analysis was carried out applying multivariate curve resolution coupled to alternating least-squares (MCR-ALS). The flexibility of this applied multivariate model allowed the prediction of the concentrations of the five analytes in complex samples including strongly coeluting analytes, elution time shifts, band shape changes and presence of uncalibrated interferents. The obtained limits of detection (in µg L(-1)) using the proposed methodology were 2.3 (carbendazim), 0.90 (thiabendazole), 12 (propoxur), 0.46 (fuberidazole) and 0.32 (carbaryl).

Three-phase hollow-fiber liquid-phase microextraction combined with HPLC-UV for the determination of isothiazolinone biocides in adhesives used for food packaging materials.

The present study deals with the development of a liquid microextraction procedure for enhancing the sensitivity of the determination of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one in adhesives. The procedure involves a three-phase hollow-fiber liquid-phase microextraction using a semipermeable polypropylene membrane, which contained 1-octanol as the organic phase in the pores of the membrane. The donor and acceptor phases are aqueous acidic and alkaline media, respectively, and the final liquid phase (acceptor) is analyzed by HPLC coupled with diode array detection. The most appropriate conditions were extraction time 20 min, stirring speed 1400 rpm, extraction temperature 50°C. The quantification limits of the method were 0.123 and 0.490 µg/g for 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, respectively. Three different adhesive samples were successfully analyzed. The procedure was compared to direct analysis using ultra high pressure liquid chromatography coupled with TOF-MS, where the identification of the compounds and the quantification values were confirmed.