Seville (sour) orange juice: Synephrine content and cardiovascular effectsin normotensive adults

The Seville orange extract Citrus aurantium contains m-synephrine (phenylep hrine) and octopamine; it causes cardiac disturbances in animals and is use d by humans for weight loss. Juice from the orange (Seville orange juice [S OJ]) is used to "knockout" intestinal cytochrome P450 (CYP) 3A4 in bioavail ability studies, The purpose of this study was to determine synephrine and octopamine concentrations in SOJ and SOJ's cardiovascular effects in normot ensive humans. Subjects consumed 8 ounces of SOJ and water in crossover fas hion followed by a repeat ingestion 8 hours later. Hemodynamic (heart rate; systolic, diastolic, and mean arterial pressure) measurements followed. Sy nephrine and octopamine were determined by high-performance liquid chromato graphy. Hemodynamics did not differ significantly between water and SOJ gro ups. Mean synephrine concentration of SOJ samples was 56.9 +/- 0.52 mug/ml; octopamine was not detected. SOJ ingestion by normotensive subjects is exp ected to be safe. Individuals with severe hypertension, tachyarrhythmias, a nd narrow-angle glaucoma and monoamine oxidase inhibitor recipients should avoid SOJ consumption. Persons taking decongestant-containing cold preparat ions should also refrain from SOJ intake. (C) 2001 the American College of Clinical Pharmacology.