Methylxanthines are alkaloids found in natural products such as tea, coffee and guaraná. These alkaloids are commonly used in cola drinks and pharmaceutical products due principally to their stimulant and diuretic effects on the human organism. In this work, experimental data on the supercritical CO2 extraction of caffeine, theophylline and theobromine from herbal maté tea, a beverage traditionally consumed by the gauchos of southern Brazil, the Argentine, Paraguay and Uruguay, were obtained using high pressure extraction equipment that allows adequate control of temperature and pressure. The continuous extraction/fractionation of maté tea leaves, Ilex paraguariensis in natura using carbon dioxide was carried out at 313.2 and 343.2 K and pressures of 13.8 and 25.5 MPa. Extraction/fractionation curves revealed the large influence of temperature and pressure on extraction yield. CO2 was also found to show a higher selectivity for caffeine than for theophylline and theobromine.

São apresentados dados sobre a conjugação de cafeína e seu derivado cafeinidina com albumina de soro bovino e sua utilização para a produção de anticorpos. Galinhas poedeiras foram imunizadas e as globulinas extraídas das gemas dos ovos. Por ensaios de imunoprecipitação pode-se verificar que ambos anticorpos reagiram com seus respectivos antígenos, cafeína e cafeinidina. Também verificou-se que a posição do radical metil em mono e dimetilxantinas era importante para o reconhecimento antígeno-anticorpo. Metilação na posição N-3 pareceu ser determinante para o reconhecimento pelo anticorpo produzido para o conjugado cafeinidina-BSA. Por outro lado, metilação na posição N-7 foi importante para o conjugado cafeína-BSA. Discute-se as vantagens de um anticorpo sobre o outro e a possibilidade de seu emprego em testes imunológicos para determinação de alcalóides purínicos totais em material vegetal e seus derivados alimentícios.

Data on the conjugation of caffeine and its derivative caffeinidine with bovine serum albumin and their use to produce antisera are reported here. Chickens were immunized with the conjugates and antisera were extracted from egg yolks. In immunoprecipitation assays it was verified that both antisera were efficient against their respective antigens. It was also observed that the methyl position in mono and dimethylxanthines played a role in the recognition by the antisera. Methyl at N-3 position seemed to be important for the precipitation by the antisera produced to caffeinidine-BSA conjugate. On the other hand, methylation at N-7 position was important for caffeine-BSA conjugate. The advantages of each antisera and their potential application in imunological tests as a tool to determine total purine alkaloids in plant material and derived foodstuffs are discussed.

Comercialmente, bulbos de Hippeastrum hybridum são propagados por escamas duplas, as quais são mantidas em vermiculita umedecida e no escuro até o aparecimento do bulbilho. No presente trabalho demonstrou-se que escamas duplas mantidas sob luz solar plena produziram bulbilhos que uma vez transferidos para condições de campo não sofreram o estresse imposto pela luz. Tais bulbilhos possuíam maior peso seco de bulbo e, devido a presença de folhas verdes, cresceram mais rápido do que bulbilhos produzidos no escuro. Um tratamento intermediário, em que as escamas foram mantidas na escuridão por um período e depois transferidas para a luz, confirmou as vantagens em se produzir bulbilhos na luz. Muito provavelmente, bulbilhos produzidos no escuro tiveram seu desenvolvimento atrasado devido a forte competição entre folhas e raízes por nutrientes e fotoassimilados.

Commercially bulbs of Hippeastrum hybridum are propagated by twin scales, which are cultured in wet vermiculite in the darkness until bulbil appearance. We showed that twin scales kept under sun light produced bulbils, that once transferred to the field, did not undergo severe light stress. They had higher bulb dry weight and due to the presence of green leaves they grew faster when transplanted to the field than bulbils produced from scales kept in the darkness. An intermediary treatment (a period of darkness followed by transference to light) confirmed the advantages of producing bulbils under sun light conditions. It appears that in the field, growth of bulbs from dark grown bulbils was retarded due to the strong competition among leaves and roots for nutrients and assimilates.