Am J Chin Med. 1995 ; 23(1): 91-9.
Observations on blood pressure responses to injections of medicinal plant extracts in rats.
Department of Biology, Chinese University of Hong Kong, Shatin.
Aqueous extracts of plant species from different families produced dose dependent decreases in blood pressure in rat within the first minute (immediate hypotensive response) and in duration of this hypotensive response following i.v. injection, while the subsequent response could be either hypotensive or hypertensive depending on plant species. The subsequent response was not dose-related in both magnitude and duration. The immediate hypotensive response was not due to the vehicle (NaCl solution) nor the common cations present in the extracts. It represented probably a reflex response with chemicals in the plant extracts acting on the peripheral chemoreceptors, or in the pacemaker and/or cardiac tissue, leading to a decrease in heart rate and tension. The subsequent hypotensive/hypertensive response was due to the chemicals acting on targets in different parts of various body systems.