980 resultados para HPLC-PDA


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Prior to obtain a standardized dried extract from V. ferruginea, lupeol was first time isolated from leaves and used as chemical maker. An analytical method using HPLC-PDA for lupeol determination in V. ferruginea intermediate products was developed using a C8 reverse-phase column, acetonitrile-acetic acid (99.99:0.01, v/v) as mobile phase at 0.8 mL min-1, oven temperature at 23-25 ºC, sample injection volume at 30 µL and detection at 210 nm. The method presented linearity from 10 to 160 µg mL-1, accuracy, precision, robustness and suitable sensitivity proving to be a useful tool to the obtainment process of lupeol standardized dried extracts of V. ferruginea.

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A perceção, as opiniões e os desejos dos consumidores têm um enorme impacto na indústria alimentar. Na perceção visual, a cor torna-se um fator fundamental e, neste campo, os corantes alimentares assumem uma extrema importância. A cor pode ser considerada um dos atributos mais impressionantes dos géneros alimentícios, que influencia diretamente a preferência e a seleção dos consumidores[1]. Existem muitos corantes naturais utilizados na indústria alimentar, tais como carotenóides, antocianinas e betalaínas. As betalaínas incluem compostos com cores que vão do vermelho-violeta (betacianidinas) ao amarelo-laranja (betaxantinas). As betalaínas não têm sido tão extensamente estudadas como as antocianinas, mas possuem uma capacidade corante três-vezes maior. A única betalaína autorizada como corante natural deriva da beterraba(E-162)[2], mas existem outras fontes alternativas de betacianidinas ,como a que se apresenta neste trabalho: Gomphrenaglobosa L., vulgarmente designada por perpétua roxa.

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As propolis is a highly valued bee product, we aimed to verify the quality of aged propolis, investigating their phenolic and flavonoid composition, levels of toxic metals, radical scavenging and antimicrobial activities. Samples of fresh and aged propolis of six different beekeepers, from the same geographical location, were investigated in terms of their phenolic and flavonoid composition and levels of Pb, Cd, and Cr, as well as radical scavenging and antimicrobial activities. The two groups of propolis had similar qualitative composition by HPLC-PDA and ESI(-)-MS. Fresh propolis and aged propolis show no differences when average values of extraction yield, flavonoids, EC50, or MIC were compared and both types of propolis showed good antimicrobial activity at low concentrations. Only levels of phenolic compounds were higher in fresh propolis. The propolis samples considered in this study, aged or fresh, had similar qualitative composition, although they were collected in different periods. Samples only differed in their levels of total phenolic content. Moreover, aged propolis conserves significant radical scavenging and antimicrobial properties. We suggest that aged propolis should not be discarded but explored for alternative applications.

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Ceylon gooseberry is a deep-purple exotic berry that is being produced in Brazil with great market potential. This work aimed to determine major phenolic compounds in this specie by HPLC-PDA-ESI/MS. Samples were collected in two different seasons. Pulp and skin were analyzed separately. Non-acylated rutinoside derivatives of delphinidin (∼60-63%) and cyanidin (∼17-21%) were major anthocyanins tentatively identified. All anthocyanins had higher concentration in skin than in pulp (64-82 and 646-534mg of cyaniding-3-glucoside equivalents/100g skin and pulp, respectively). Moreover, anthocyanin profile changed between sampling dates (p<0.05). Mainly for delphinidin-3-rutinoside which could be a result of season variation. In this specie, non-anthocyanin polyphenols represent less than 35% of total extracted polyphenols. The tentative identification proposed a flavonol and three ellagitannins as major compounds of the non-anthocyanin phenolics fraction. Finally, anthocyanin is the major phenolic class in this fruit and its composition and content are significantly affected by season.

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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.

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Cultivar, growing conditions and geographical origin are factors that influence the carotenoid composition in fruits. Because the loquat cultivars evaluated in this study, CentenAria, Mizauto, Mizuho, Mizumo and Nectar de Cristal, have not previously been investigated, the present work was carried out to determine and compare the carotenoid composition of these five loquat cultivars, by applying high-performance liquid chromatography connected to a photodiode array and mass spectrometry detectors (HPLC-PDA-MS/MS). Twenty-five carotenoids were separated on a C(30) column, and 23 of them were identified. All-trans-beta-carotene (19-55%), all-trans-beta-cryptoxanthin (18-28%), 5,6:5`,6`-diepoxy-beta-cryptoxantilin (9-18%) and 5,6-epoxy-beta-cryptoxanthin (7-10%) were the main carotenoids. The total carotenoid content ranged from 196 mu g/100 g (cv. Nectar de Cristal) to 3020 mu g/100 g (CV. Mizumo). The carotenoid profile of cv. Nectar de Cristal was different from the other cultivars, which was in agreement with its cream pulp colour, in contrast to the other four cultivars with orange pulp colour. Cultivars Mizauto, Mizuho, Mizumo and CentenAria showed provitamin A values between 89 and 162 mu g RAE/100 g, and can be considered good source of this provitamin. (C) 2009 Elsevier Inc. All rights reserved.

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(+/-)-Licarin A (1), a neolignan obtained by the oxidative coupling reaction of isoeugenol, had in this study its enantiomers resolved. A novel, quick and efficient enantiomeric resolution of 1 was directly performed by chiral high-performance liquid chromatography (HPLC-PDA) protocol (CHIRALPACK (R) AD column; 9:1 (v/v) n-hexane:2-propanol; 1.0 mL/min). This method provided a chromatogram profile with a well-resolved peak separation. After isolation of each enantiomer with ee >99.9%, they were analysed in a polarimeter. Compound 2, which showed a retention time (t(r)) of 12.13 min, was the (+)-enantiomer and compound 3 (t(r) =18.90 min) was the (-)-enantiomer. (C) 2011 Elsevier B.V. All rights reserved.

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The reactive oxygen species (ROS) produced by neutrophils are involved in the pathogenesis of several diseases, for which the intake of antioxidants could benefit patients either as a prophylactic or therapeutic treatment. Propolis is among the known antioxidants, and its chemical composition may vary under the influence of seasonality, which may interfere in its biological properties. This work evaluates the role of seasonality on the production of some important compounds of propolis samples produced monthly from November 2001 through October 2002 as well as the effect of these samples on the oxidative metabolism of stimulated neutrophils, by using both luminol and lucigenin to produce chemiluminescence (CLlum and CLluc, respectively). The cytotoxicity of the most active extracts to neutrophils was also investigated. The inhibitory effect of the propolis samples varied significantly during the studied period for both assays (3.4 +/- 1.1 to 16.0 +/- 1.1 mu g/mL for CLlum and 6.2 +/- 2.0 to 30.0 +/- 5.0 mu g/mL for CLluc), which was also observed in the quantitative profile of the main analyzed compounds (aromadendrin-4`-methyl ether, artepillin C, and baccharin). This effect started to become more prominent during the fall and, among all the studied extracts, the one obtained in May displayed the highest inhibitory effect on CL production (3.4 +/- 1.1 mu g/mL for alum and 6.2 +/- 2.0 mu g/mL for CLluc). The HPLC qualitative profiles of the extracts of propolis samples were quite similar, but there was a huge variation in terms of quantitative profile. It seems that aromadendrin-4`-methyl ether and baccharin play an essential role in the antioxidant activity, while artepillin C is not very important for this effect. The extracts presenting the highest antioxidant activity were produced in May, June, and August, and they did not display cytotoxicity at 25 mu g/mL; quercetin, used as control, was not toxic to neutrophils at 8.5 mu g/mL (C) 2010 Elsevier B.V. All rights reserved.

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Acai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in Acai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of Acai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The Acai pulp doses selected were 3.33, 10.0 and 16.67 g/kg b.w. administered by gavage alone or prior to DXR (16 mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with acai pulp (24 h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic. and flavonoids in Acai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH > 13) comet assay. There were no statistically significant differences (p > 0.05) between the negative control and the groups treated with the three doses of Acai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of Acai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in Acai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of Acai as a health promoter. (C) 2009 Elsevier B.V. All rights reserved.

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In the present study, the ethanolic extracts of fourteen edible mushrooms were investigated for their anti-inflammatory potential in LPS (lipopolysaccharide) activated RAW 264.7 macrophages. Furthermore the extracts were chemically characterized in terms of phenolic acids and related compounds. The identified molecules (p-hydroxybenzoic, p-coumaric and cinnamic acids) and their glucuronated and methylated derivatives obtained by chemical synthesis were also evaluated for the same bioactivity, in order to establish structure-activity relationships and to comprehend the effects of in vivo metabolism reactions in the activity of the compounds. The extracts of Pleurotus ostreatus, Macrolepiota procera, Boletus impolitus and Agaricus bisporus revealed the strongest anti-inflammatory potential (EC50 values 96 ± 1 to 190 ± 6 µg/mL, and also the highest concentration of cinnamic acid (656 to 156 µg/g), which was also the individual compound with the highest anti-inflammatory activity. The derivatives of p-coumaric acid revealed the strongest properties, specially the derivative methylated in the carboxylic group (CoA-M1) that exhibited similar activity to the one showed by dexamethaxone used as anti-inflammatory standard; by contrast, the derivatives of p-hydroxybenzoic revealed the lowest inhibition of NO production. All in all, whereas the conjugation reactions change the chemical structure of phenolic acids and may increase or decrease their activity, the glucuronated and methylated derivatives of the studied compounds are still displaying anti-inflammatory activity.

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An efficient screening strategy for the identification of potentially interesting low-abundance antifungal natural products in crude extracts that combines both a sensitive bioautography assay and high performance liquid chromatography (HPLC) microfractionation was developed. This method relies on high performance thin layer chromatography (HPTLC) bioautography with a hypersusceptible engineered strain of Candida albicans (DSY2621) for bioactivity detection, followed by the evaluation of wild type strains in standard microdilution antifungal assays. Active extracts were microfractionated by HPLC in 96-well plates, and the fractions were subsequently submitted to the bioassay. This procedure enabled precise localisation of the antifungal compounds directly in the HPLC chromatograms of the crude extracts. HPLC-PDA-mass spectrometry (MS) data obtained in parallel to the HPLC antifungal profiles provided a first chemical screening about the bioactive constituents. Transposition of the HPLC analytical conditions to medium-pressure liquid chromatography (MPLC) allowed the efficient isolation of the active constituents in mg amounts for structure confirmation and more extensive characterisation of their biological activities. The antifungal properties of the isolated natural products were evaluated by their minimum inhibitory concentration (MIC) in a dilution assay against both wild type and engineered strains of C. albicans. The biological activity of the most promising agents was further evaluated in vitro by electron microscopy and in vivo in a Galleria mellonella model of C. albicans infection. The overall procedure represents a rational and comprehensive means of evaluating antifungal activity from various perspectives for the selection of initial hits that can be explored in more in-depth mode-of-action studies. This strategy is illustrated by the identification and bioactivity evaluation of a series of antifungal compounds from the methanolic extract of a Rubiaceae plant, Morinda tomentosa, which was used as a model in these studies.

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The genus Plumbago belongs to the family Plumbaginaceae, order Plumbaginales. Comparative chemical profile of P. scandens (native) and P. auriculata (cultivated) was obtained by normal and reversed-phase high performance liquid chromatography with photodiode array detector. Comparison of the ultraviolet espectra and the retention times for the compounds allowed to find similar metabolic patterns in roots, stems and leaves. Four flavonoids, one phenolic acid or derivative and the naphtoquinone plumbagin were comparatively identified to standards.

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The main analytical variables of a modified Folin-Ciocalteu method were studied by UV-Vis and gradient HPLC-PDA methods, using purified (PC) and technical grade (TGC) casein. Rutin and an aqueous extract of Psidium guajava L. leaves were used as models. The best results were ascribed to TGC. Certainly PC bonds the polyphenols of the P. guajava extract better than TGC, but TGC afforded better precision. A lack of specificity occurred when rutin was analyzed together with the P guajava extract. Additional analyses performed with the flavonoid fraction of P. guajava extract by HPLC-PDA had confirmed that casein was able to bind catechin, gallic acid and P. guajava flavonoids in a non-specific way.

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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.