Acute oral intake of a higenamine-based dietary supplement increases circulating free fatty acids and energy expenditure in human subjects

BACKGROUND: Higenamine, also known as norcoclaurine, is an herbal constituent thought to act as a beta-2 adrenergic receptor agonist—possibly stimulating lipolysis. It was the purpose of this study to determine the impact of a higenamine-based dietary supplement on plasma free fatty acids and energy expenditure following acute oral ingestion. METHODS: Sixteen healthy subjects (8 men; 26.1 ± 2.5 yrs; 8 women 22.4 ± 3.1 yrs) ingested a dietary supplement containing a combination of higenamine, caffeine (270 mg), and yohimbe bark extract or a placebo, on two separate occasions in a double-blind, randomized, cross-over design, separated by 6–8 days. Blood samples were collected immediately before ingestion, and at 30, 60, 120, and 180 minutes post ingestion, and analyzed for plasma free fatty acids (FFA) and glycerol. Breath samples were collected at the same times for a measure of kilocalorie expenditure and respiratory exchange ratio (RER) using indirect calorimetry. Heart rate and blood pressure were recorded at all times. Data collection occurred in the morning following a 10 hour overnight fast. RESULTS: A condition effect was noted for both FFA (p < 0.0001) and kilocalorie expenditure (p = 0.001), with values higher for supplement compared to placebo at 60, 120, and 180 minutes post ingestion. No statistically significant effects were noted for glycerol or RER (p > 0.05). A condition effect was noted for heart rate (p = 0.03) and systolic blood pressure (p < 0.0001), with values higher for supplement compared to placebo. CONCLUSION: Ingestion of a higenamine-based dietary supplement stimulates lipolysis and energy expenditure, as evidenced by a significant increase in circulating FFA and kilocalorie expenditure. The same supplement results in a moderate increase in heart rate (~3 bpm) and systolic blood pressure (~12 mmHg), which is consistent with previous studies evaluating moderate doses of caffeine and yohimbine, suggesting that higenamine contributes little to the increase in these hemodynamic variables. These findings are in reference to young, healthy and active men and women.