title: Presence of blood-pressure lowering and spasmolytic constituents in Buddleja crispa.
abstract: 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.
authors.affiliation: 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
authors.forename: Anwarul H
authors.initials: AH
authors.lastname: Gilani
authors.forename: Ishfaq A
authors.initials: IA
authors.lastname: Bukhari
authors.forename: Rafeeq A
authors.initials: RA
authors.lastname: Khan
authors.forename: Abdul J
authors.initials: AJ
authors.lastname: Shah
authors.forename: Ijaz
authors.initials: I
authors.lastname: Ahmad
authors.forename: Abdul
authors.initials: A
authors.lastname: Malik
mesh_terms: 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
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D010276:Parasympatholytics; D010936:Plant Extracts; D002084:Butylated Hydroxytoluene; C006008:BH 3; D002118:Calcium