Presence of blood-pressure lowering and spasmolytic constituents in Buddleja crispa.
This aim of this study was to investigate the crude extract of Buddleja crispa (Bc.Cr) and its active constituent(s) for their antihypertensive and antispasmodic activities. The Bc.Cr caused a dose-dependent (3-10 mg/kg) fall in mean arterial pressure in rats under anesthesia. In rabbit aorta preparations, Bc.Cr (0.03-1 mg/mL) caused inhibition of high K(+) (80 mM) precontractions. The Bc.Cr (0.03-1 mg/mL) also inhibited spontaneous and high K(+) precontractions in rabbit jejunum preparations, suggestive of calcium channel blocking (CCB) activity. CCB activity was further confirmed when pretreatment of the tissues with Bc.Cr (0.03-0.10 mg/mL) caused a rightward shift in Ca(++) concentration response curves, similar to verapamil. Among the pure compounds, BdI-H3 was more potent against the high K(+) than spontaneous contractions and was around eight times more potent than Bc.Cr against the spontaneous contractions while the other two compounds, BdI-2 and BH-3 were inactive. Activity-directed fractionation revealed that the hexane fraction was more potent against K(+) precontractions. These data indicate that Bc.Cr possesses a blood-pressure lowering effect, mediated possibly through CCB, though additional mechanism(s) cannot be ruled out. Among the pure compounds, Bdl-H3 is likely to be the active compound involved in the spasmolytic and possibly BP lowering effect of the parent crude extract.
Gilani
Anwarul H
AH
Drug Discovery and Natural Products Research Unit, Department of Biological and Biomedical Sciences, Aga Khan University Medical College, Karachi-74800, Pakistan. anwar.gilani@aku.edu
Bukhari
Ishfaq A
IA
Khan
Rafeeq A
RA
Shah
Abdul J
AJ
Ahmad
Ijaz
I
Malik
Abdul
A
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D032861:Buddleja / Q000737:chemistry*; D002084:Butylated Hydroxytoluene / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007583:Jejunum / Q000187:drug effects; D015394:Molecular Structure; D009119:Muscle Contraction / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D010276:Parasympatholytics; D010936:Plant Extracts; D002084:Butylated Hydroxytoluene; C006008:BH 3; D002118:Calcium