Willian Ferreira da Costa

Development of a green chromatographic method for determination of colorants in food samples.

A green chromatographic analytical method for determination of Tartrazine, Brilliant Blue and Sunset Yellow in food samples is proposed. The method is based on the modification of a C18 column with a 0.25% (v/v) Triton X-100 aqueous solution at pH 7 and in the usage of the same surfactant solution as mobile phase without the presence of any organic solvent modifier. After the separation process on the chromatographic column, the colorants are detected at 430, 630 and 480 nm, respectively. The chromatographic procedure yielded precise results and is able to run one sample in only 8 min, consuming 15.0mg of Triton X-100 and 38.8 mg of phosphate. When the flow rate of the mobile phase is 1 ml min(-1) the retention times are 2.1, 3.6 and 7.0 min for Tartrazine, Brilliant Blue and Sunset Yellow, respectively; and all peak resolutions are ca. 2. The analytical curves present the following linear equations: area=7.44 10(5)+2.71 10(5) [Tartrazine] (R=0.998, n=7); area=1.09 10(5)+3.75 10(5) [Brilliant] (R=0.9995, n=7) and area=-7.34 10(4)+2.33 10(5) [Sunset] (R=0.998), n=7) and, the limits of detection for Tartrazine, Brilliant Blue and Sunset Yellow were estimated as 0.125, 0.080 and 0.143 mg l(-1). When the proposed method is applied to food samples analysis, precise results are obtained (R.S.D.<5%, n=3) and in agreement with those obtained by using the classical spectrophotometric method. The traditional usage of organic solvent as mobile phase in HPLC is not used here, which permits to classify the present method as green.

Preparation and characterization of activated carbon from a new raw lignocellulosic material: Flamboyant (Delonix regia) pods

Activated carbons were prepared from flamboyant pods by NaOH activation at three different NaOH:char ratios: 1:1 (AC-1), 2:1 (AC-2), and 3:1 (AC-3). The properties of these carbons, including BET surface area, pore volume, pore size distribution, and pore diameter, were characterized from N(2) adsorption isotherms. The activated carbons obtained were essentially microporous and had BET surface area ranging from 303 to 2463 m(2) g(-1).(13)C (CP/MAS and MAS) solid-state NMR shows that the lignocellulosic structures were completely transformed into a polycyclic material after activation process, thermogravimetry shows a high thermal resistance, Boehm titration and Fourier-transform infrared spectroscopy allowed characterizing the presence of functional groups on the surface of activated carbons. Scanning electron microscopy images showed a high pore development. The experimental results indicated the potential use of flamboyant pods as a precursor material in the preparation of activated carbon.

Synthesis and antitumoral activity of novel 3-(2-substituted-1,3,4-oxadiazol-5-yl) and 3-(5-substituted-1,2,4-triazol-3-yl) β-carboline derivatives

Several novel 1-substituted-phenyl beta-carbolines bearing the 2-substituted-1,3,4-oxadiazol-5-yl and 5-substituted-1,2,4-triazol-3-yl groups at C-3 were synthesized and evaluated for their in vitro anticancer activity. The assay results pointed thirteen compounds with growth inhibition effect (GI(50)<100 microM) for all eight different types of human cancer cell lines tested. The beta-carbolines 7a and 7h, bearing the 3-(2-metylthio-1,3,4-oxadiazol-5-yl) group, displayed high selectivity and potent anticancer activity against ovarian cell line with GI(50) values lying in the nanomolar concentration range (GI(50)=10 nM for both compounds). The 1-(N,N-dimethylaminophenyl)-3-(5-thioxo-1,2,4-triazol-3-yl) beta-carboline (8g) was the most active compound, showing particular effectiveness on lung (GI(50)=0.06 microM), ovarian and renal cell lines. The potent anticancer activity presented for synthesized compounds 7a, 7h, and 8g, together with their easiness of synthesis, makes these compounds promising anticancer agents.

pKa determinations of xanthene derivates in aqueous solutions by multivariate analysis applied to UV-Vis spectrophotometric data.

Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the pKa determination and the attribution of each group to the corresponding pKa value is a very important feature. Attempts to obtain reliable pKa through the potentiometry titration and the electronic absorption spectrophotometry using the first and second orders derivative failed. Due to the close pKa values allied to strong UV-Vis spectral overlap, multivariate analysis, a powerful chemometric method, is applied in this work. The determination was performed for eosin Y, erythrosin B, and bengal rose B, and also for other synthesized derivatives such as 2-(3,6-dihydroxy-9-acridinyl) benzoic acid, 2,4,5,7-tetranitrofluorescein, eosin methyl ester, and erythrosin methyl ester in water. These last two compounds (esters) permitted to attribute the pKa of the phenolic group, which is not easily recognizable for some investigated dyes. Besides the pKa determination, the chemometry allowed for estimating the electronic spectrum of some prevalent protolytic species and the substituents effects evaluation.

Development of a green chromatographic method for determination of fat-soluble vitamins in food and pharmaceutical supplement.

A green chromatographic analytical method for determination of fat-soluble vitamins (A, E, D3 and K1) in food and pharmaceutical supplement samples is proposed. The method is based on the modification of a C18 column with a 3.00% (w/v) sodium dodecyl sulphate (SDS) aqueous solution at pH 7 (0.02 mol L(-1) phosphate buffer solution) and in the usage of the same surfactant solution as mobile phase with the presence of 15.0% (v/v) butyl alcohol as an organic solvent modifier. After the separation process, the vitamins are detected at 230 nm (K1, D3 and E), 280 nm (A, E, D3 and K1) and 300 nm (K1, D3 and E). The chromatographic procedure yielded precise results (better than 5%) and is able to run one sample in 25 min, consuming 1.5 g of SDS, 90 mg of phosphate and 7.5 mL of butyl alcohol. When the flow rate of the mobile phase is 2 mL min(-1) the retention times are 4.0, 9.6, 13.0 and 22.7 min for D3, A, E and K1 vitamins, respectively; and all peak resolutions are higher than 2. The analytical curves present the following linear equations: area=6290+34852 (vitamin A), R2=0.9998; area=4092+36333 (vitamin E), R2=0.9997; area=-794+30382 (vitamin D3) R2=0.9998 and area=-7175+82621 (vitamin K1), R2=0.9996. The limits of detection and quantification for vitamins A, E, D(3) and K(1) were estimated for a test pharmaceutical vitamin supplement sample as 0.81, 1.12, 0.91 and 0.83 mg L(-1) and 2.43, 3.36, 2.73 and 2.49, respectively. When the proposed method was applied to food and pharmaceutical sample analysis, precise results were obtained (R.S.D.<5% and n=3) and in agreement with those obtained by using the classical chromatographic method that uses methanol and acetonitrile as mobile phase. Here, the traditional usage of toxic organic solvent as mobile phase is avoided, which permits to classify the present method as green.

Synthesis and antitumor activity of novel 1-substituted phenyl 3-(2-oxo-1,3,4-oxadiazol-5-yl) β-carbolines and their Mannich bases.

A series of novel 1-(substituted phenyl)-3-(2-oxo-1,3,4-oxadiazol-5-yl) β-carbolines (4a-e) and the corresponding Mannich bases 5-9(a-c) were synthesized and evaluated for their in vitro antitumor activity against seven human cancer cell lines. Compounds of 4a-e series showed a broad spectrum of antitumor activity, with GI50 values lower than 15μM for five cell lines. The derivative 4b, having the N,N-dimethylaminophenyl group at C-1, displayed the highest activity with GI50 in the range of 0.67-3.20μM. A high selectivity and potent activity were observed for some Mannich bases, particularly towards resistant ovarian (NCI-ADR/RES) cell lines (5a, 5b, 6a, 6c and 9b), and ovarian (OVCAR-03) cell lines (5b, 6a, 6c, 9a, 9b and 9c). In addition, the interaction of compound 4b with DNA was investigated by using UV and fluorescence spectroscopic analysis. These studies indicated that 4b interact with ctDNA by intercalation binding.

Determination by GC-MS-SIM of furanoditerpenes in Pterodon pubescens Benth.: development and validation.

The crude hydroalcoholic extract from fruits of P. pubescens is widely used because of its anti-rheumatic, antinociceptive and anti-inflammatory activities. Furanoditerpenes have a vouacapan skeleton and are involved with the pharmacological activity of the oil extracted from P. pubescens fruits. Furanoditerpenes methyl 6α-acetoxy-7β-hydroxyvouacapan-17β-oate and methyl 6α-hydroxy-7β-acetoxyvouacapan-17β-oate from P. pubescens were isolated and identified. The present study developed and validated a GC-MS-SIM method for the separation and quantification of vouacapan constituents in a semipurified extract from P. pubescens fruits. The GC-MS analyses were carried out using a system equipped with a HP-5 capillary column (30 m × 0.25 mm). Temperature program: 100°C (4°C min(-1))-270°C (5 min), injector 260°C, detector 270°C. Helium was used as the carrier gas (0.7 bar, 1 mL min(-1)). The MS was taken at 70 eV. Scanning speed was 0.5 scans s(-1), from 50 to 650. Sample volume was 1 μL. Split 1:20. Analyses for validation of methodology were conducted by GC-MS-SIM (Single Ion Monitoring), where the ions monitored were 131, 145 and 146 (between 43 and 44.5 min), 105, 145 and 197 (from 44.5 to 45.3 min) and 131, 178 and 312 (from 45.3 to 48.5 min).Validation of the analytical method was based on the following parameters: linearity, robustness, limits of detection and quantification, precision (within-day and between-day variabilities), recovery and stability. The method was linear over a range of 12.81-2.56 μγμΛ(-1) of vouacapan 1, 112.78-22.56 μg mL(-1) of vouacapan 2, and 333.34-66.67 μg mL(-1) of vouacapans 3 and 4, with detection limits of 0.39, 3.45 and 9,44 μg mL(-1) and quantification limits of 1.19, 10.47 and 28.62 μg mL(-1), respectively. Recovery values were 100.69%, 97.48% and 96.98% for vouacapans 1, 2 and 3-4, respectively. Thus, the method was efficient to separate and quantify furanoditerpenes in the extract or fraction.

Anti-inflammatory and Antioxidant Activities of Randia Hebecarpa. and Major Constituents

Abstract The methanol extract of Randia hebecarpa. Benth. (Rubiaceae) leaves was evaluated for anti-inflammatory activity using carrageenan- and dextran-induced rat paw edema models. Antioxidant activities of the methanol extract and of the fractions resulting from its partition were also measured using the 1,1-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and the linoleic acid peroxidation method. The methanol extract, ethyl acetate fraction, and hydromethanol fraction exhibited percent inhibition of lipid peroxidation comparable to that of commercial antioxidant butylated hydroxytoluene (BHT). Fractionation of the ethyl acetate and hydromethanol fractions through chromatographic methods yielded kaempferol-3, 7-O.-α.-L-dirhamnoside, kaempferol-3-O.-β.-D-galactoside, quercetin-3-O.-β.-D-galactoside, myricetin-3-O.-α.-L-rhamnoside, kaempferol-3-O.-α.-L-rhamnosyl-(1 → 6)-β.-D-galactosyl-7-O.-α.-L-rhamnoside, quinovic acid-3-O.-β.-D-quinovopyranosil-28-O.-β.-D-glucopyranoside, cincholic acid 3-O.-β.-D-quinovopyranosil-28-O.-β.-D-glucopyranoside, and the sugar D-mannitol.

Chemical Composition and Cytotoxic Activity of the Root Essential Oil from Jatropha ribifolia (Pohl) Baill (Euphorbiaceae)

The essential oil of roots of Jatropha ribifolia, obtained by hydrodistillation, was characterized in terms of its chemical composition by chromatographic method with flame ionization detection (GC-FID) and gas chromatography coupled to electron ionization mass spectrometry (GC-MS). The analyses and identification pointed by mass fragmentation pattern and retention index revealed the presence of 49 compounds, representing 91.4% of the total oil, with 39.5% of monoterpenes, 43.0% of sesquiterpenes and 8.5% of phenylpropanoids. The major compounds of the oil were β-pinene (9.2%), isoeugenol methyl ether (8.5%), vatirenene (8.4%), α-gurjunene (7.0%), endo-8-hydroxy-cycloisolongifolene (6.6%), α-pinene (6.4%) and p-menth-1-en-8-ol (5.2%). The fractionation by preparative thin layer chromatography (TLC) allowed obtaining five fractions (F1-F5) with different compound contents from the original oil. Some essential oil components showed a significant increase in their levels after fractionation, as borneol (17.9%, F1), 3-thujopsanone (19.1%, F4), isoeugenol methylether (21.2%, F2), 8-oxo-9H-cycloisolongifolene (21.4%, F4), 8-cis-5(1H)-azulenone,2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-(1-methylethylidene) (23.1%, F4) e endo-8-hydroxy-cycloisolongifolene (38.6%, F2). These fractions and oil were tested in vitro against nine human cancer cell lines by sulforhodamine B assay. The Jatropha oil was more effective in inhibiting the growth of cells NCI-H460 (drug resistant ovarian; GI50 6.2 µg mL–1) and OVCAR-3 (ovarian; GI508.0 µg mL–1). The cancer cells line PC-3 (prostate) was more sensitive to the effects of the fractions showing significant values of GI50 such as for fraction F1, F2 and F4 (< 0.25 µg mL–1). In general the antiproliferative activity of the fractions was more pronounced than that of crude oil.

Development of a green microwave assisted extraction method for triazine herbicides determination in soil samples

It was developed a green microwave-assisted extraction method for determination of triazine herbicides in soil samples. The extraction strategy was based on micellar medium associated to microwaves followed by the herbicides determination by HPLC in such way that the procedure could be considered as green. Two portions (10 and 8 mL) of aqueous SDS (sodium dodecyl sulphate) 0.06% (m/v) were used as extracting solutions associated to 0.500 g of sample and the following microwave oven program: 540 W (6 min), 0 W (1 min), 630 W (2 min). The analytical curves were linear in the analytical range of 0.05 up to 10.0 mg L-1 for atrazine, ametryne and simazine. The limits of detection and quantification were estimated as 0.90, 0.57 and 0.235 µg g-1 and 3.1, 1.9 and 0.8 µg g-1 for atrazine, ametryne and simazine, respectively. The proposed method is precise (RSD < 8%, n = 3) and the obtained results are in agreement with the classical one. Recovery tests for soil samples indicated that the percentage of recuperation were between 82.0 e 94.0%.