CA-SCOPARIA EXTRACT(+ CHANNEL BLOCKING ACTIVITY OF ARTEMISIA)

Intravenous administration of a hydro-methanolic extract of Artemisia scoparia (3-30 mg/kg) produced hypotensive and bradycardiac effects. T hese effects remained unaltered in atropine treated animals and the pr esence of the extract did not modify the vasoconstrictor response of n orepinephrine, indicating that cardiovascular effects of the plant ext ract are not mediated through activation of muscarinic receptors or ad renoceptor blockade. In the in vitro studies, it suppressed the sponta neous movements of rabbit jejunum in a concentration-dependent (0.1-1 mg/mL) manner. The plant extract inhibited K+-induced tonic contractio n in a manner similar to that of verapamil. Exposure of tissue to Ca+-free Kreb's solution abolished the spontaneous movements which were r estored on addition of Ca++. In tissue pretreated with plant extract o r verapamil, addition of Ca++ (50 mu M) failed to restore spontaneous contractions. These data indicate that Artemisia scoparia cntains Ca+ channel blocker-like constituent(s) which may explain the hypotensive effect observed in vivo and the traditional use of the plant as a spa smolytic.