Bioactivity-guided isolation of spasmolytic components of Pycnocycla spinosa Decne ex Boiss

Hydroalcoholic extract of Pycnocycla spinosa has spasmolytic effect in vitro and antidiarrhoeal action in vivo. The aim of this research was to separate fractions of total hydroalcoholic extract of P. spinosa guided by their spasmolytic activity. Aerial parts of P. spinosa were extracted with ethanol. The concentrated extract was subjected to column chromatography and thin layer chromatography. Initially four fractions were obtained (F1, F2, F3, and F4) and their spasmolytic activities were determined on ileum contraction induced by KCl (80 mM). The more active fraction was subjected to further isolation and tested to find its most active components. The active component was phytochemically characterized using phytochemical methods including ultraviolet and infrared spectroscopy. Hydroalcoholic extract of P. spinosa (10-320 mg/ml) in a concentration dependent manner inhibited ileum contraction with the IC50 value of 47 ± 8.1 ?g/ml (mean ± S.E.M., n=6). Fraction F2 was the most potent inhibitor of ileum contraction (IC50= 3.4 ± 0.33 ?g/ml). From five sub-fractions separated from fraction F2 (F2a, F2b, F2c, F2d, and F2e, respectively), F2c was a more active component with the IC50 value of 2.6 ± 0.27 ?g/ml. The primary results of target fraction (F2c) showed sugar moiety in its structure or in one of its components. In this research we have isolated pharmacological active fraction which is most likely responsible for antispasmodic action of P. spinosa hydroalcoholic extract.