Considering C. aurantium contains biologically active adrenergic amines, it may exert sympathomimetic activity.
An in vivo study found no significant effects on blood pressure when two concentrations of C. aurantum tincture (standardised to 4% synephrine or 6% synephrine) were administered (Calapai et al 1999). However, analysis of myocardial electrical activity showed ECG alterations such as ventricular arrhythmias with enlarged QRS complex. The effect was present after 5 days of treatment and became significant at day 10 and was still evident after 1 5 days. These effects may be explained by the positive chronotropic activity of synephrine, which has been observed on isolated atria from reserpinised guinea pigs due to beta-,-adrenoceptor agonist activity, but could also be due to other constituents.
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