Purpose:
To evaluate the effects of the methanol extract of
Acanthus montanus
on guinea pig
trachealis muscle.
Methods:
Guinea pig tracheae were set up in 10 ml organ baths. The effect of the methanol extract
of
Acanthus montanus (0.5 - 8 mg/ml) on the spontaneous tone of the trachea and carbacholprecontracted
trachea in the absence and presence of propranolol, glibenclamide and procaine was
studied.
Results:
The extract (0.5 – 8.0 mg/ml) produced a concentration-dependent relaxation of the intrinsic
tone in tracheal preparations which was completely blocked by propranolol (3 x 10
-7 M), glibenclamide
(10
-7 M) and procaine (10
-3 M). The extract (0.5 - 8 mg/ml) produced a concentration-dependent
relaxation of carbachol (10
-5M)-precontracted trachea. This effect of the extract was partially blocked by
propranolol (3 x 10
-7M), procaine (10
-3M) and glibenclamide (10
-7M) with a progressive increase in the
median effective concentration (EC
50) values as follows: control, 0.66mg/ml > propranolol, 1.42mg/ml >
glibenclamide, 1.54mg/ml > procaine, 2.04 mg/ml.
Conclusion:
The results obtained suggest that the extract produces a non-specific smooth muscle
relaxant effect mediated via ß-adrenergic receptor mechanism or potassium channels.