Abstract Guarana (Paullinia cupana) is a native plant from the Amazon whose seeds contain a high concentration of caffeine. Aqueous extract of guarana is widely used in the world. In this study, the objective was to develop and validate a High-Performance Liquid Chromatography method for the determination of caffeine in extracts and commercial beverages based on guarana. A sensitive, simple, and viable high performance liquid chromatographic method without the need of an analyte extraction procedure was developed and validated according to Brazilian and international requirements. The method presented high performance, fulfilling Brazilian and international requirements, in addition to allowing product compliance tests. Results confirmed high selectivity and linearity (>0.999) between 5 to 135 ug/mL, with no significant matrix effect. Detection and quantification limits were 0.02 µg/mL and 2 µg/mL, respectively. Precision was less than 4 %, and accuracy varied from 99.9-120 %. Applicability of the method was demonstrated by conducting a limited evaluation in products containing caffeine. Commercial extracts showed quite different caffeine levels, while carbonated drinks follow Brazilian and American recommendations. Our results indicate that the developed method can be used to evaluate the quality of the guarana extract and of products containing caffeine.

The medicinal plants Panax ginseng C. A. Meyer (Araliaceae) and Heteropterys tomentosa A. Juss (Malpighiaceae) are widely and separately used by the Brazilian population as phytotherapeutics for the same medicinal purposes as tonics and to improve cognition. A chemical analysis was carried out on hydroethanolic extracts of powdered roots from P. ginseng and H. tomentosa using HPLC-DAD-ESI-MS/MS (High Performance Liquid Chromatography coupled to Diode-Array Detector and Electrospray Ionization - Mass Spectrum/Mass Spectrum). The ginsenosides Rg1, Rf, mRg and mRf were the main constituents in a hydroethanolic extract from P. ginseng, while in the hydroethanolic extract from H. tomentosa, caffeoylquinic acid derivatives and astilbin isomers were the main constituents. Concentration-time-effect curves were generated in cultures of astrocytes that were incubated with hydroethanolic extracts of these species to elucidate their toxicities. The P. ginseng extract was nontoxic at all of the tested times and concentrations. The hydroethanolic extract from H. tomentosa demonstrated toxicity at a concentration of 1000 µg/mL. P. ginseng extract had no protective effect against staurosporine. Many studies have demonstrated the neuroprotective effect of ginsenosides, caffeoylquinic derivatives and flavonoids.

RESUMO Objetivo Avaliar a composição fitoquímica do extrato hidroetanólico das partes aéreas de Turnera diffusa Willd (Turneraceae; T. diffusa) e sua toxicidade em astrócitos. Métodos Análises químicas do extrato hidroetanólico de partes aéreas de T. diffusa foram feitas por HPLC-DAD-ESI-MS/MS. Os ensaiosin vitro utilizaram culturas de astrócitos para avaliar morte celular. Resultados Flavonas-C, O-diglicosídeos, como, luteolina-8-C-[6-deoxi-2-O-raminosil]-xilo-hexos-3-ulosideo, apigenina-8-C-[6-deoxi-2-O-raminosil]-xilo-hexos-3-ulosideo e apigenina-7-O-6”-p-cumaroilglucosídeo foram os principais constituintes encontrados neste extrato hidroetanólico. Uma curva tempo-concentração demonstrou toxicidade desse extrato na concentração de 1.000µg/mL, na cultura de astrócitos após 6 e 24 horas de incubação. Conclusão Nas análises fitoquímicas, importantes antioxidantes, sobretudo flavonoides, foram observados. Extratos de T. diffusa apresentaram efeitos citotóxicos em altas concentrações, ocasionando aumento de morte celular em cultura de astrócitos.

ABSTRACT Objective To evaluate the phytochemical composition of hydroethanolic extracts from powdered aerial parts of Turnera diffusa Willd (Turneraceae; T. diffusa), as well as its toxicity in astrocytes. Methods Chemical analyses of hydroethanolic extract from powdered aerial parts ofT. diffusa were carried out using HPLC-DAD-ESI-MS/MS.In vitro assays using astrocytes culture were performed to evaluate cell death. Results Flavone-C, O-diglycosides, such as, luteolin-8-C-[6-deoxy-2-O-rhamnosyl]-xylo-hexos-3-uloside, apigenin-8-C-[6-deoxy-2-O-rhamnosyl]-xylo-hexos-3-uloside and apigenin-7-O-6”-p-coumaroylglucoside were the main compounds found in this hydroethanolic extract. Concentration time-effect demonstrated the toxicity of this extract at a concentration of 1,000µg/mL in astrocyte culture, after 6 and 24 hours of incubation. Conclusion In phytochemical analyses, important antioxidants (mainly flavonoids) were observed. T. diffusa extracts presented cytotoxic effect in high concentrations, leading to increased cell death in astrocyte culture.

Este trabalho avaliou a interferência da origem e do teor de compostos fenólicos de óleo essencial de orégano (OEO) de cinco marcas comerciais provenientes de diferentes regiões do mundo, na atividade inibitória frente à Salmonella Enteritidis (SE). A composição de cada OEO foi determinada por cromatografia gasosa acoplada ao espectrômetro de massas (CG-IE-MS). A atividade inibitória frente SE in vitro foi avaliada pela técnica de difusão em poços, empregando-se soluções alcoólicas a 0,1; 0,2; 0,5; 1,0; ou 2,0%, observando-se a formação de halo de inibição após incubação a 30 °C por 24 horas. Como resultado da análise por CG-IE-MS, foram identificados dezessete componentes voláteis. Todos OEO analisados neste trabalho possuíam carvacrol como componente principal e apresentaram atividade antimicrobiana frente a SE nas cinco concentrações testadas. A ação inibitória das cinco marcas comerciais avaliadas não apresentou diferença estatística significativa (p > 0,05), porém o OEO proveniente da região do Mediterrâneo com p-cimeno e γ-terpineno, além de carvacrol, apresentou maiores halos de inibição de SE que os demais OEO. Concluiu-se que a multiplicação de Salmonella Enteritidis in vitro pode ser inibida por OEO cuja ação antimicrobiana independe da região produtora de orégano. No entanto, óleos essenciais que possuem p-cimeno e γ-terpineno, além de carvacrol, podem ter o seu efeito antimicrobiano potencializado.

This study evaluated the influence of the origin and content of phenolic compounds in five Oregano Essential Oil (OEO) brands, from different part of the world, on the inhibitory activity against Salmonella Enteritidis (SE). The composition of each OEO was determined by gas chromatography coupled to mass spectrometry (GC-MS-IE). The inhibitory activity on SE was evaluated by the agar well diffusion test using alcoholic solutions at 0.1, 0.2, 0.5, 1.0, or 2.0%, observing the formation of inhibition halos after 24 hours of incubation at 30 °C. Using a GC-MS-IE seventeen volatile components were identified. Carvacrol was the major component of all OEO samples. They were active against SE in all tested concentrations. The differences in the inhibitory activity presented by the five brands were not significant (p > 0.05), but the OEO from the Mediterranean, which contained p-cymene and γ-terpinene besides carvacrol, resulted in larger inhibition halos than the other OEO. It was concluded that the in vitro growth of Salmonella Enteritidis can be inhibited by OEO, regardless the region in which oregano is produced. However, the essential oils that contain carvacrol, p- cymene, and γ-terpinene may present a more effective antimicrobial effect.

A atividade antioxidante de extratos de frutas (acerola, amora, açaí e morango) e compostos puros foi avaliada por meio de dois métodos: sistema beta-caroteno/ácido linoléico e método de seqüestro de radicais livres (DPPH• - 2,2-difenil-1-picrilhidrazila). As metodologias foram previamente adaptadas para a realização em microplacas, de forma a reduzir a quantidade de reagentes e amostras necessárias, aumentar o número de análises simultâneas e permitir a automatização das leituras de absorbância. Os resultados mostraram que a atividade antioxidante dos extratos metanólicos dos frutos estava de acordo com a apresentada pelos compostos puros, isto é ácido ascórbico e compostos fenólicos, nos dois sistemas. O extrato de acerola, devido ao seu alto conteúdo de vitamina C, comportou-se como pró-oxidante e os de açaí, amora e morango como antioxidantes no sistema beta-caroteno/ácido linoléico. Entretanto, quando avaliado pelo método de seqüestro de radicais livres, o extrato de acerola apresentou a maior atividade antioxidante, seguido pelos extratos de amora, açaí e morango. As adaptações realizadas nos métodos de avaliação de atividade antioxidante utilizando microplaca permitiram a realização de múltiplas análises simultâneas, além de minimizar significativamente o uso de reagentes e amostras.

The antioxidant activity of fruit extracts (acerola, açaí, black-berry and strawberry) and pure compounds has been analysed by two methods: beta-carotene/linoleic acid and DPPH•(2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. First, those methodologies were adapted to be performed in microplates, in order to reduce the sample and reagent amounts, to increase the number of simultaneous analyses and to automate absorbance lectures. The results showed that the antioxidant activity of the fruit extracts was in accordance with those of pure ascorbic acid and phenolic compounds, in the two systems. The acerola extract, due to its high vitamin C content, acted as pro-oxidant, but açaí, black-berry and strawberry extracts acted as antioxidants in -carotene/linoleic acid system. However, by the DPPH• radical scavenging assay the acerola extract presented the highest antioxidant activity, followed by açaí, black-berrry and strawberrry. The adaptation of methods to evaluate the antioxidant activity using microplate allowed the realization of multiple analyses simultaneously and minimized significantly the use of reagents and samples.