title: Bacopa monnieri and its constituents is hypotensive in anaesthetized rats and vasodilator in various artery types.
abstract: BACKGROUND
  Bacopa monnieri (Brahmi) provides traditional cognitive treatments possibly reflecting improved cerebral hemodynamics. Little is known about the cardiovascular actions of Brahmi. We sought to assess its effects on blood pressure and on isolated arteries, thus providing insights to clinical applications.
  
  
  METHODS
  Intravenous Brahmi (20-60 mg/kg) was tested on arterial blood pressure and heart rate of anaesthetized rats. In vitro vasorelaxation was assessed in arteries, with and without blockers of nitric oxide synthase (L-NAME), cyclooxygenase (indomethacin), and mechanical de-endothelialisation. The effects of Brahmi on Ca(2+) influx and release from stores were investigated.
  
  
  RESULTS
  Intravenous Brahmi extract (20-60 mg/kg) decreased systolic and diastolic pressures without affecting heart rate. Brahmi evoked relaxation in isolated arteries in order of potency: basilar (IC50=102 ± 16 μg/ml)>mesenteric (171 ± 31)>aortae (213 ± 68)>renal (IC50=375 ± 51)>tail artery (494 ± 93)>femoral arteries (>1,000 μg/ml). Two saponins, bacoside A3 and bacopaside II, had similar vasodilator actions (IC50=8.3 ± 1.7 and 19.5 ± 6.3 μM). In aortae, without endothelium or in L-NAME (10-4M), Brahmi was less potent (IC50=213 ± 68 to 2170 ± 664 and 1192 ± 167 μg/ml, respectively); indomethacin (10-5M) was ineffective. In tail artery, Brahmi inhibited K(+)-depolarization induced Ca(2+) influx and Ca(2+) release from the sarcoplasmic reticulum by phenylephrine (10-5M) or caffeine (20mM).
  
  
  CONCLUSIONS
  Brahmi reduces blood pressure partly via releasing nitric oxide from the endothelium, with additional actions on vascular smooth muscle Ca(2+) homeostasis. Some Brahmi ingredients could be efficacious antihypertensives and the vasodilation could account for some medicinal actions.
authors.affiliation: Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Natakorn
authors.initials: N
authors.lastname: Kamkaew
authors.forename: C Norman
authors.initials: CN
authors.lastname: Scholfield
authors.forename: Kornkanok
authors.initials: K
authors.lastname: Ingkaninan
authors.forename: Putcharawipa
authors.initials: P
authors.lastname: Maneesai
authors.forename: Helena C
authors.initials: HC
authors.lastname: Parkington
authors.forename: Marianne
authors.initials: M
authors.lastname: Tare
authors.forename: Krongkarn
authors.initials: K
authors.lastname: Chootip
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D034681:Bacopa / Q000737:chemistry; D001794:Blood Pressure / Q000187:drug effects*; D020013:Calcium Signaling / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D007262:Infusions, Intravenous; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D014665:Vasodilator Agents; D019001:Nitric Oxide Synthase; D011451:Prostaglandin-Endoperoxide Synthases