Determination of phenolic compounds and antioxidant activity of green, black and white teas of Camellia sinensis (L. ) Kuntze, Theaceae / Determinação de compostos fenólicos e atividade antioxidante dos chás, verde, preto, e branco, de Camellia sinensis (L. ) Kuntze, Theaceae

Green, black and white teas are all produced from leaves and shoots of Camellia sinensis, the only difference is how they are processed. The aim of this study was to compare the total phenols and flavonoid contents and antioxidant capacity of green, black and white tea bags of different brands. The morphodiagnosis of leaves was used to identification of plant material. HPLC-DAD fingerprinting coupled with Principal Component Analysis (PCA) was applied to analyze similarities of the tea samples. The results showed considerable variability between tea brands in both total phenols (30.55 to 60.85 mg of pyrogallol/g) and flavonoids (6.35 to 8.92 mg of quercetin/g). Green and white teas demonstrated the highest ABTS and DPPH radical scavenging activities.

Os chás verde, preto e branco são produzidos de folhas e brotos de Camellia sinensis, diferenciando-se pelo processamento. O objetivo deste estudo foi comparar o conteúdo de fenóis totais, flavonoides e capacidade antioxidante dos chás verde, preto e branco de diferentes marcas na forma de sachês. A análise morfo-anatômica das folhas foi realizada para a identificação do material vegetal. Os perfis químicos (fingerprints) obtidos por Cromatografia Líquida de Alta Eficiência (CLAE - DAD) foram analisados por ferramentas quimiométricas de análise exploratória (PCA) para análise comparativa entre as amostras. Os resultados evidenciaram considerável variação entre as marcas de chás, tanto para fenóis totais (30,55 a 60,85 mg de pirogalol/g), quanto para flavonoides (6,35 a 8,92 mg de quercetina/g). As amostras de chá verde e de chá branco apresentaram maior atividade antioxidante contra os radicais ABTS e DPPH.

Solid state evaluation of some thalidomide raw materials.

Thalidomide presents polymorphism and is a problematic drug due to its poor solubility and difficult tablet processability, which is the dosage form available in Brazil. In most cases, the pharmacopoeias specify do not address solid state characterization of drugs precisely. In this work, different thalidomide commercial samples were characterized by infrared spectroscopy, particle size analysis, scanning electron microscopy, and X-ray diffraction. In addition, the polymorphic forms were quantified for Rietveld analysis and their intrinsic dissolution rates were evaluated. The results demonstrated the market availability of different raw materials which lack of homogeneity due to differences related to crystalline constitution, crystal habit and intrinsic dissolution rate.

Characterization of different samples of quercetin in solid-state: indication of polymorphism occurrence.

The present work was designed to compare four commercial samples of quercetin, three of them presenting pharmaceutical grade (QPGa, QPGb and QPGc) and the other one pro-analysi grade (QPA) by means of different techniques. Physical and chromatographic characterization of these samples shows different properties following its origin, especially a clear evidence of polymorphism occurrence.

Carbamazepine/betaCD/HPMC solid dispersions. II. Physical characterization.

Solid dispersions containing carbamazepine (CBZ) associated with beta-cyclodextrin (betaCD) and/or hydroxypropyl methylcellulose were prepared by two different methods, spray-drying or physical mixture, and characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), infrared (IR) spectroscopy, and x-ray powder diffraction analysis (XRPD) studies. Scanning electron microscopy pictures showed that spray-drying produced a mixture of hollow, spherical, and partially shrunken microparticles of homogeneous materials, whereas the physical mixtures yielded heterogeneous systems in which all individual components could be identified. Thermal and IR analyses suggest the existence of a strong interaction between CBZ and excipients in spray-dried solid dispersions, but no CBZ polymorphic transition was detected by either IR spectroscopy or XRPD analysis after the spray-drying process.