Pharmacological Studies on Platycodon grandiflorum A. DC. III. Activities of Crude Platycodin on Respiratory and Circulatory Systems and Its Other Pharmacological Activities

Abstract

Pharmacological studies on crude platycodin, a saponin fraction extracted from the roots of Platycodon grandifiorum A. DC., were carried out in addition to previous studies which revealed antihistaminic, anticholinergic, and potent anti-inflammatory effect. Results obtained from the present study were as follows : In guinea-pigs, a median antitussive dose (AtD₅₀) of crude platycodin is 6.4 mg/kg, i.p., and the permeability of Evans Blue into the respiratory tract fluid was increased significantly by its divided oral administrations. A transient hypotension, a decrease in heart rate, and depression of respiration were observed by its intravenous administration in anesthetized rats. The femoral and coronary blood flows in anesthetized dogs were considerably increased by its close arterial injections and these effects were found to be more potent than those of papaverine hydrochloride. In the isolated atrium of guinea-pigs, a negative inotropic effect was exhibited only in the high concentrations of crude platycodin, and its antagonism against acetyl-choline was observed. A mydriatic effect, inhibition of intestinal propulsion, and lack of local anesthetic effect were also found. It is, therefore, concluded that crude platycodin has antitussive, expectorant, hypotensive, and vasodilative effects, and the anticholinergic effect was reconfirmed.