Antispasmodic effects of Pycnocycla spinosa seed and aerial part extracts on rat ileum and uterus smooth muscle contractions

Abstract

Background and the purpose of study: Hydroalcoholic extract of Pycnocycla spinosa has a relaxant effect on ileum and inhibits castor oil induced diarrhoea in mice. However, effects of P. spinosa seed extracts on ileum and uterus hasn't been investigated.  The aim of this study was to investigate effect of P. spinosa seed and extracts of the aerial part on rat ileum and uterus smooth muscle contraction.

Methods: A 70% ethanol extract of seed and aerial parts of P. spinosa was prepared by a percolation method. Uterine horns or ileum were dissected from non-pregnant female Wistar rats (200-230g) and cut into longitudinal strips and mounted for isotonic recording under 1g tension in Tyrode's solution. Effects of the extracts were examined on tonic contractions induced by KCl (80mM) on both tissues and on phasic spasm induced by oxytocin (0.002iu/ml) on the uterus.

Results: The aerial part extract inhibited rat ileum contractions induced by 80mM KCl (IC₅₀=42±3.4mg/ml) in a concentration dependent manner and it also inhibited rat uterus contraction induced by 80 mM KCl. However, its inhibitory effects were observed with higher concentration of the extract (IC₅₀=420±90mg/ml) and at concentration of 1.28mg/ml of the extract in the bath the response was 19±7%. 

The aerial part extract (40-640mg/ml) also reduced the evoked phasic response of uterus by oxytocin (IC₅₀=71±17.3mg/ml). The seed extract reduced the uterus response to oxytocin in a concentration-dependent manner, and inhibited tissue response completely at 160mg/ml (IC₅₀=27±4mg/ml). 

Major conclusion: From this study it was concluded that the seed extract of P. spinosa have similar inhibitory properties on rat isolated uterus and ileum contractions, while the extract of the aerial part of P. spinosa is more selective inhibitor of ileum contraction, and at higher concentrations it also inhibits uterus spasm.