Antispasmodic and bronchorelaxant activities of Salsola imbricata are mediated through dual Ca+2 antagonistic and β-adrenergic agonistic effects.

CONTEXT: Salsola imbricata Forssk. (Chenopodiaceae) has folkloric repute for the treatment of various gastrointestinal and respiratory ailments.

OBJECTIVE

The present study investigates spasmolytic and bronchorelaxant effects of S. imbricata.

MATERIALS AND

METHODS

The crude aqueous-ethanol extract of the aerial parts of S. imbricata and its fractions, in cumulative concentrations (0.01-10 mg/mL), were tested on contractions of isolated rabbit jejunum and tracheal preparations. Furthermore, concentration response curves (CRCs) of Ca+2 and carbachol were constructed in the absence and presence of the extract. Standard organ bath methods were used.

RESULTS

The crude extract relaxed spontaneous, K+ (80 mM) and carbachol (1 μM)-induced contractions in jejunum preparations with respective EC50 values of 0.40 (0.35-0.46), 0.69 (0.60-0.79) and 0.66 (0.57-0.75) mg/mL. It shifted Ca+2 CRCs rightward in nonparallel manner. In isolated tracheal preparations, the crude extract caused relaxation of K+ (80 mM) and carbachol (1 μM)-induced contractions with EC50 values of 0.86 (0.75-0.98) and 0.74 (0.66-0.84) mg/mL, respectively. It displaced carbachol CRCs rightward with suppression of maximal response. In both tissues, pretreatment with propranolol (1 μM) caused rightward shift in inhibitory CRCs of the extract against carbachol-induced contractions. The ethyl acetate fraction was found more potent in relaxing smooth muscle contractions than the parent extract and its aqueous fraction.

DISCUSSION AND

CONCLUSION

The results suggest that the spasmolytic and bronchorelaxant activities of S. imbricata are related to Ca+2 antagonistic and β-adrenergic agonistic effects, thus justifying some of the traditional uses of the plant.