Possible mechanisms of action of the neutral extract from Bidens pilosa L. leaves on the cardiovascular system of anaesthetized rats.
The aim of this study was to investigate the hypotensive and cardiac effects of the neutral extract from Bidens pilosa leaves. Intravenous administration of the extract resulted in a biphasic dose-related hypotensive activity. In normotensive rats (NTR), B. pilosa decreased systolic blood pressure by 18.26%, 42.5% and 30% at doses of 10, 20 and 30 mg/kg, respectively. In spontaneously hypertensive rats (SHR), the decrease in systolic blood pressure was 25.77%, 38.96% and 28.64% at the above doses, respectively. These doses induced hypotension by 27%, 34.13% and 18.73% respectively in salt-loaded hypertensive rats. In NTR, B. pilosa reduced heart rate by 23.68% and 61.18% at doses of 20 and 30 mg/kg, respectively. The force of contraction of the heart was only affected at 30 mg/kg. The initial phase of hypotensive response was partially inhibited by atropine while propranolol increased this effect. These results suggest that B. pilosa exhibited its fi rst hypotensive effects by acting on the cardiac pump efficiency and secondly through vasodilation.
Dimo
T
T
Department of Animal Biology and Physiology, Faculty of Sciences, PO Box 812, University of Yaounde I, Yaounde, Cameroon.
Nguelefack
T B
TB
Tan
P V
PV
Yewah
M P
MP
Dongo
E
E
Rakotonirina
S V
SV
Kamanyi
A
A
Bopelet
M
M
D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D031176:Bidens; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced / Q000517:prevention & control; D007262:Infusions, Intravenous; D009200:Myocardial Contraction / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride
D000959:Antihypertensive Agents; D010936:Plant Extracts; D012965:Sodium Chloride