The Aqueous Calyx Extract of Hibiscus sabdariffa Lowers Blood Pressure and Heart Rate via Sympathetic Nervous System...

Area of Science:

• Cardiovascular Physiology
• Pharmacology
• Herbal Medicine Research

Background:

• The known antihypertensive effects of Hibiscus sabdariffa (HS) in humans and animals warrant further investigation into its underlying mechanisms.
• Previous research suggests a potential role for the sympathetic nervous system in mediating the hypotensive effects of HS.

Purpose of the Study:

• To test the hypothesis that the blood pressure-lowering effect of Hibiscus sabdariffa is mediated by the sympathetic nervous system.
• To evaluate the impact of HS on sympathetic nervous system activation during physiological stress.

Main Methods:

• Twenty healthy subjects participated in the study.
• Subjects underwent the cold pressor test (CPT) and handgrip exercise (HGE) before and after oral administration of 15mg/Kg of HS.
• Blood pressure (BP) and heart rate (HR) responses, including mean arterial pressure (MAP), were digitally measured.

Main Results:

• Both CPT and HGE significantly increased MAP and HR from basal levels without HS.
• In the presence of HS, the increases in MAP and HR induced by CPT and HGE were significantly reduced compared to when HS was absent.
• HS administration notably dampened the sympathetic response to both cold stress and isometric exercise.

Conclusions:

• The significant reduction in sympathetic nervous system-mediated increases in blood pressure and heart rate by HS provides indirect evidence for its mechanism of action.
• Hibiscus sabdariffa may exert its hypotensive effect through the attenuation of sympathetic nervous system discharge.
• These findings support the use of Hibiscus sabdariffa as a natural intervention for managing hypertension.