Über das Vorkommen and die Bedeutung von Flavonen, Flavonolen and Flavanonen in Lebensmitteln

Effects of the flavonoids extracted from Spergularia purpurea Pers. on arterial blood pressure and renal function in normal and hypertensive rats

The antihypertensive and diuretic effects of the flavonoids extracted from Spergularia purpurea Pers. (SP) were studied both in normotensive (NTR) and spontaneously hypertensive conscious rats (SHR). Daily oral administration of the flavonoid mixture (5 mg/kg for 1 week) exhibited a significant decrease in blood pressure with variation coefficient (Delta) of 20 in SHR rats and 11 in NTR rats. The systolic and diastolic blood pressure decreased significantly and respectively with 17 and 24% in SHR, and with 11 and 16% in NTR. The flavonoid mixture enhanced significantly the water excretion in hypertensive (P<0.001) and normal rats (P<0.001). Furthermore, oral administration of flavonoids mixture at a dose of 5 mg/kg produced a significant increase of urinary excretion of sodium (P<0.01), potassium (P<0.05) and chlorides (P<0.05) in SHR. Similarly, the flavonoid administration induced a significant increase of urinary electrolytes elimination in NTR (P<0.01 versus controls). No significant changes were noted on heart rate after flavonoids treatment in SHR as well as in NTR. While, glomerular filtration rate showed a significant increase after administration of flavonoids in all groups (P<0.05). These results suggest that oral administration of flavonoids obtained from Spergularia purpurea exhibited antihypertensive and diuretic actions.

The effect of grapefruit juice on cyclosporine and prednisone metabolism in transplant patients

OBJECTIVE

To estimate the effect of grapefruit juice on cyclosporine and prednisone metabolism.

METHODS

This was an open, placebo-controlled, two-way crossover study performed in the academic departments of clinical pharmacology and nephrology. On two study occasions, 12 kidney transplant patients with stable cyclosporine trough levels received either grapefruit juice or water every 3 hours for a period of 30 hours. The main outcome measures were peak concentration and time to peak, area under the concentration-time curve, the ratio of the area under the curve of the metabolites/area under the curve of the parent drug, terminal half-life, and 24-hour trough levels of cyclosporine.

RESULTS

Grapefruit juice increased the peak concentration of cyclosporine by 185 ng/ml (95% confidence interval, 60 to 310; p = 0.008). The ratio of the area under the curve of the metabolites of cyclosporine to the area under the curve of cyclosporine was reduced by 0.137 on the grapefruit day (95% confidence interval, -0.221 to -0.054; p = 0.004). After grapefruit juice, no significant changes were observed in the area under the curve and the time to peak of cyclosporine, prednisone, and prednisolone. Cyclosporine trough levels were unchanged by grapefruit juice.

CONCLUSIONS

Grapefruit juice inhibits the metabolism of cyclosporine for a brief period after administration, which may be explained by the inhibition of cytochrome P450 enzymes in the gut wall and to a lesser extent by inhibition of these enzymes in the liver. Grapefruit juice can be one of the factors leading to intraindividual variability in the pharmacokinetics of cyclosporine. Grapefruit juice had no significant effect on the metabolism of prednisone or prednisolone.

[Review on nonessential constituents of vegetables. I. Cumcumbers, melons, squashes and pumpkins, bell peppers, eggplants, peas, beans, and broad beans (author's transl)]

In this paper the known constituents of the vegetables mentioned in the title are reviewed, except for proteins, carbohydrates, triglyceride-fatty acids, and vitamins, with particular emphasis on volatiles, organic acids, phenolics, crotenoids, sterols, bitter principles, nonprotein-N-compounds.

[The phenolics of fruits. VIII. Changes in flavonol concentrations during fruit development (authors transl)]

In black currants the contents of quercetin- and especially of myricetin glycosides increased during ripeness very considerably. The myricetin level in ripe fruits of cultivated blueberries and the quercetin level in ripe berries of privet was higher than in unripe. However, the concentrations of kaempferol and quercetin glycosides were in most of the fruits (e.g. red and white currants, sour cherries, plums, cultivated blueberries, elderberries) smaller than in unripe fruits. Anthocyanin formation is therefore not combined with an accumulation of flavonols (perhaps with the exception of myricetin).