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| VITORIA, A. P.; MAZZAFERA, P.. |
| The coffee species Coffea dewevrei and Coffea arabica have marked differences in caffeine metabolism and the control of the caffeine content during fruit ripening and leaf aging is still not clear. The aim of this work was a detailed investigation on the alkaloid degradation in young and aged leaves, and immature and mature fruits of these species. Young and aged leaves, and immature and mature fruits were fed with (2-14 C) caffeine. After an incubation period they were extracted for (2-14 C) caffeine and metabolites and analysed by reversed-phase liquid chromatography and radiocounting of collected fraction. In leaves and fruits of Coffea dewevrei there were higher degradation rates of caffeine. In both species, compared to young tissues, aged leaves and... |
| Tipo: Artigo em periódico indexado (ALICE) |
Palavras-chave: Metabolismo da cafeina; Cafe; Metilxantinas; Caffeine metabolism; Coffee; Methylxanthines. |
| Ano: 1998 |
URL: http://www.alice.cnptia.embrapa.br/handle/doc/86984 |
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| Sartor,Rosana Mary; Mazzafera,Paulo. |
| The low caffeine content in leaves of C. dewevrei (~ 0.5 mg/g) is due to a low biosynthesis associated with a fast degradation. On the other hand, high biosynthesis and low degradation confer a higher content (~ 8 mg/g) in leaves of C. arabica. In this work it was observed that cell cultures of C. dewevrei recovered the ability to synthesize caffeine almost in similar levels of C. arabica cultures. Tracer experiments with labelled carbon dioxide showed a significant accumulation of radioactivity in caffeine and metabolites, indicating an active biosynthesis. When the cultures were fed with labelled caffeine most of the radioactivity was recovered in caffeine, indicating that although active, degradation was not so efficient as in leaves, and therefore,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffee; Caffeine; Cell suspension culture; Methylxanthines. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132000000100009 |
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| Mota,A.; Silva,P.; Neves,D.; Lemos,C.; Calhau,C.; Torres,D.; Martel,F.; Fraga,H.; Ribeiro,L.; Alçada,M.N.M.P.; Pinho,M.J.; Negrão,M.R.; Pedrosa,R.; Guerreiro,S.; Guimarães,J.T.; Azevedo,I.; Martins,M.J.. |
| Alkaline phosphatase (ALP) is important in calcification and its expression seems to be associated with the inflammatory process. We investigated the in vitro acute effects of compounds used for the prevention or treatment of cardiovascular diseases on total ALP activity from male Wistar rat heart homogenate. ALP activity was determined by quantifying, at 410 nm, the p-nitrophenol released from p-nitrophenylphosphate (substrate in Tris buffer, pH 10.4). Using specific inhibitors of ALP activity and the reverse transcription-polymerase chain reaction, we showed that the rat heart had high ALP activity (31.73 ± 3.43 nmol p-nitrophenol·mg protein-1·min-1): mainly tissue-nonspecific ALP but also tissue-specific intestinal ALP type II. Both ALP isoenzymes... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart; Alkaline phosphatase; Polyphenol-rich beverages; Steroid hormones; Methylxanthines. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000700009 |
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| Angelucci,M.E.M.; Cesário,C.; Hiroi,R.H.; Rosalen,P.L.; Cunha,C. Da. |
| We studied some of the characteristics of the improving effect of the non-specific adenosine receptor antagonist, caffeine, using an animal model of learning and memory. Groups of 12 adult male Wistar rats receiving caffeine (0.3-30 mg/kg, ip, in 0.1 ml/100 g body weight) administered 30 min before training, immediately after training, or 30 min before the test session were tested in the spatial version of the Morris water maze task. Post-training administration of caffeine improved memory retention at the doses of 0.3-10 mg/kg (the rats swam up to 600 cm less to find the platform in the test session, P<=0.05) but not at the dose of 30 mg/kg. Pre-test caffeine administration also caused a small increase in memory retrieval (the escape path of the rats... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Memory; Learning; Caffeine; Methylxanthines; Adenosine receptor antagonist; Morris water maze. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001000013 |
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