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International Journal of Medical Sciences

.: Home > International Journal of Medical Sciences > 2011 > Volume 8 Number 3 > John G. Seifert1ƒx, Aaron Nelson2, Julia Devonish2, Edmund R. Burke3, and Sidney J. Stohs4

Effect of Acute Administration of an Herbal Preparation on Blood Pressure and Heart Rate in Humans

John G. Seifert1ƒx, Aaron Nelson2, Julia Devonish2, Edmund R. Burke3, and Sidney J. Stohs4
1. Movement Science/Human Performance Laboratory, Montana State University, Bozeman, MT, USA 2. Human Performance Laboratory, St. Cloud State University, St. Cloud, MN, USA 3. Dept of Biology, Colorado University – Colorado Springs, Colorado Springs, CO, USA 4. School of Pharmacy and Health Professions, Creighton University Medical Center, Omaha, NE, USA
Abstract :

Confusion and controversy exist regarding the cardiovascular effects of dietary supplements containing caffeine and Citrus aurantium (bitter orange) extract. The primary protoalkaloidal ingredient in bitter orange extract is p-synephrine which has some structural similarities to ephedrine and nor-epinehrine, but exhibits markedly different pharmacokinetic and receptor binding properties. The goal of this study was to investigate the cardiovascular effects of a product containing caffeine, bitter orange extract (p-synephrine) and green tea extract in mildly overweight individuals. Fourteen female and nine male subjects (age 24.7 +7.4 yrs, BMI: 26.6 +3.8) volunteered in this randomized, placebo-controlled, crossover, double-blind de-signed study. On day one, subjects entered the laboratory following an overnight fast. Heart rate and blood pressure were recorded at 60 min. Expired air was analyzed for the next 10 min of the session. At each of three meals, subjects ingested one capsule that was either a non-caloric placebo or a dietary supplement that contained 13 mg p-synephrine and 176 mg caffeine. On the following day, the subjects returned and repeated the protocol for data collection beginning 60 min after consuming one capsule of the placebo or the dietary sup-plement. No effects of the dietary supplement on heart rate, systolic and diastolic blood pressure or mean arterial pressure were observed. No between or within group differences were observed when data were analyzed for gender and caffeine usage. A small but significant decrease in resting respiratory exchange ratio was observed for the low caffeine user group in response to the product containing caffeine and p-synephrine. The results of this study in-dicate that ingestion of a product containing bitter orange extract, caffeine and green tea extract does not lead to increased cardiovascular stress and that fat oxidation may increase in certain populations.

Keywords :
Citrus aurantium, p-synephrine, blood pressure, heart rate, bitter orange, caffeine, green tea

Date Deposited : 04 Jul 2011 10:57

Last Modified : 04 Jul 2011 10:57

Official URL:

Volume 8, Number 3, - 2011 , ISSN 1449-1907

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