The aim of this study was to test the usefulness of the metabolite/caffeine ratio for the evaluation of hepatic dysfunction. Subjects with liver cirrhosis and chronic hepatitis, as well as healthy volunteers, were given the oral dose of 300 mg caffeine. Blood samples were collected after 4, 8, and 12 hours. Concentrations of caffeine (CA) and its three metabolites-paraxanthine (PX), theobromine (TB), and theophylline (TP)-were determined by high-performance liquid chromatography. Pharmacokinetic parameters of caffeine and PX/CA, TB/CA, and TP/CA ratios were calculated. Elimination of caffeine was decreased in cirrhotics in comparison with healthy volunteers, as proved by the values of clearance (0.035 vs. 0.094 L/h/kg), elimination coefficient (0.061 vs. 0.153 h(-1)), and half-life (11.4 vs. 4.3 h). Serum metabolite/caffeine ratios were significantly reduced in cirrhotic patients: PX/CA by more than 80%, TB/CA by 50% to 70%, and TP/CA by 40% to 70%. The reduction of the ratios in chronic hepatitis patients was lower and did not occur at all time points. A high correlation was found between caffeine clearance and metabolite/caffeine ratios. Metabolite/caffeine ratios calculated in a single blood sample collected 8 or 12 hours after caffeine administration could provide a practical assessment of hepatic function in cirrhotic patients. The value of the test for the chronic hepatitis patients is limited.

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Polyphenolics can act as prooxidants leading to the generation of reactive oxygen species and electrophilic metabolites which bind to DNA, protein and glutathione. The aim of the present study was to evaluate potential adverse effects of the long-term dietary administration of freeze-dried chokeberry juice to rats. Groups of 8 males and 8 females were exposed via diet to 0; 2; 6; 10 g juice/kg feed for 90 days. Mean food consumption and mean body weight gain of treated animals were comparable with controls. Changes in some hematological parameters were sporadic and non-dose-responsive. Several statistically significant changes in clinical chemistry parameters were considered no toxicologically relevant since they were of small magnitude and lacked correlating findings in histopathology. Histopathological examination did not reveal any changes that could be attributed to chokeberry juice intake. Determination of oxidative damage markers in the liver demonstrated no damage of lipids, proteins and DNA. Chokeberry juice intake improved antioxidant status of rats as evidenced by a decrease in the level of lipid peroxidation, an increase in reduced glutathione concentration and an increase in some antioxidant enzymes activity. It could be concluded that freeze-dried chokeberry juice is safe at doses tested and can be used as a component of food supplements.

No abstract