Grapefruit concentrated

Bronner WE, Beecher GR. Extraction and measurement of prominent flavonoids in orange and grapefruit concentrates. J Chromatogr A 1995 705 247-256. 

Reverse phase procedures were used for the separation of the major flavonoid disaccharide glycosides in orange and grapefruit concentrates, and anion-exchange columns with pulsed amperometric detection allowed the separations of the oligosaccharides of honeys. From this, fingerprints were developed for the types of honeys none of the constituent oligomers was identified," ... 

P Schmeidlin-Ren, DJ Edwards, ME Fitzsimmons, K He, KS Lown, PM Woster, A Rahman, KE Thummel, JM Fisher, PF Hollenberg, PB Watkins. Mechanisms of enhanced oral availability of CYP3A4 substrates by grapefruit constituents decreased enterocyte CYP3A4 concentration and mechanism-based inactivation by furanocoumarins. Drug Metab Dispos 25 1228-1233, 1997. 

Kantola, T., Kivisto, K. T., Neuvonen, P. J., Grapefruit juice greatly increases serum concentrations of lovastatin and lovastatin add, Clin. Pharmacol. Ther. 1998, 63, 397—402. 

Cyclosporine is an immunomodulating agent used mainly to inhibit rejection after transplantations and it has a narrow therapeutic interval. Grapefruit juice is a strong inhibitor of the cyclosporine metabolism (CYP 3A4) and increases the blood concentration of cyclosporine. This can lead to toxicity but can also be used to reduce the doses and decrease the costs of the cyclosporine treatment. 

In general, the direct response of plants to all oxidant pollutants has been in the foliage. In several cases of long-term exposure (grapefruit after several months of exposure to ambient oxidants) or high ozone concentration over a shorter period (apple,peach ), injury has been reported on fruit itself. 

In an attempt to influence flavor characteristics, CHS antisense and overexpression constructs were introduced into grapefruit by Agrobacterium tumefaciens [16, 59]. CHS overexpression constructs were shown to lead to morphological abnormalities and frequently to death, while a number of CHS antisense constructs resulted in a statistically significant reduction in flavonoid content in the transgenic plants even though there was a large variation in the flavonoid concentration [16]. 

Bioavailability of felodipine is not affected by food, but increased more than 2-fold when taken with doubly concentrated grapefruit juice vs water or orange juice. High-fat meals and grapefruit juice with nisoldipine should be avoided. 

Coadministered grapefruit juice has been reported to increase tacrolimus blood trough concentrations in liver transplant patients. 

Drug/Food interactions Administration of food with A/eora/decreases the ADC and Cmax of cyclosporine. A high-fat meal consumed within 30 minutes of Neoral administration decreased the AUC by 13% and Cmax by 33%. The effects of a low-fat meal were similar. In addition, do not take cyclosporine simultaneously with grapefruit juice unless specifically instructed to do so trough cyclosporine concentrations may be increased. 

The concomitant intake of grapefruit juice increases the concentration of many drugs (e.g., testosterone, sildenafil) in humans. Such actions appear to be mediated mainly by the suppression of the cytochrome P450 enzyme CYP3A4 in the small intestine. The resultant diminished first-pass metabolism and increased bioavailability can lead to increased drug levels in the blood. Because sildenafil is metabolized by CYP3A and to a... 

Avoid taking cilostazol with grapefruit juice because it may increase the drug s blood concentration and risk of toxicity... 

Verapamil, diltiazem, erythromycin, and itraconazole all increase the plasma concentration of buspirone. The plasma concentration is decreased almost 10-fold by rifampicin. Grapefruit juice increases the overall subjective effect of the drug (Mahmood and Saha-jwalla, 1999). 

The clinical relevance of data obtained from studies with single compounds is questionable, because most studies were performed in in vitro systems, limiting the predictability of the effects of the examined compounds in vivo. Moreover, some polyphenolics, such as quercetin, were shown to interact with the absorption or metabolism of drugs only at very high concentrations (50-100 pmol/L), which are likely to exceed the expected in vivo concentration after the consumption of a moderate amount of a grapefruit/ citrus product. Also, flavonoids have been demonstrated to potentially induce apoptosis in cell lines at concentrations comparable to those used for some in vitro drug interaction studies (64-66). This potentially could have impaired the investigation of enzyme and transporter activities. 

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