Pharmacological basis for the use of Borago officinalis in gastrointestinal, respiratory and cardiovascular disorders.
OBJECTIVE
In this study, we investigated the crude extract of Borago officinalis leaves (Bo.Cr) for its antispasmodic, bronchodilator, vasodilator and cardio-depressant activities to rationalize some of the traditional uses.


METHODS
Bo.Cr was studied using different isolated tissue preparations including rabbit jejunum, trachea, aorta, and guinea-pig atria.


RESULTS
Bo.Cr which was tested positive for flavonoids, coumarins, sterols and tannins produced a concentration-dependent relaxation of spontaneous and K+ (80mM)-induced contractions in isolated rabbit jejunum preparations, suggestive of Ca++ antagonist effect, which was confirmed when pretreatment of the tissue with Bo.Cr produced a rightward shift in the Ca++ concentration-response curves like that caused by verapamil. In rabbit tracheal preparations, Bo.Cr relaxed the carbachol (1microM) and K+-induced contractions. Verapamil also produced non-specific inhibitory effect. In rabbit aorta preparations, Bo.Cr exhibited vasodilator effect against phenylephrine and K+-induced contractions similar to verapamil. When tested in guinea-pig atria, Bo.Cr caused inhibition of both atrial force and rate of contractions.


CONCLUSIONS
These results suggest that the spasmolytic effects of Bo.Cr are mediated possibly through Ca++ antagonist mechanism, which might explain the traditional use of Borago officinalis in hyperactive gastrointestinal, respiratory and cardiovascular disorders.
Gilani
Anwarul Hassan
AH
Department of Biological and Biomedical Sciences, Aga Khan University Medical College, Karachi 74800, Pakistan. anwar.gilani@aku.edu
Bashir
Samra
S
Khan
Arif-ullah
AU
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D029683:Borago; D002118:Calcium / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005767:Gastrointestinal Diseases / Q000188:drug therapy*; D006168:Guinea Pigs; D007583:Jejunum / Q000187:drug effects / Q000502:physiology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology; D011817:Rabbits; D012140:Respiratory Tract Diseases / Q000188:drug therapy*; D014132:Trachea / Q000187:drug effects / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
D010936:Plant Extracts; D014700:Verapamil; D002118:Calcium