O. Parry et al., THE SKELETAL-MUSCLE RELAXANT ACTION OF PORTULACA-OLERACEA - ROLE OF POTASSIUM-IONS, Journal of ethnopharmacology, 40(3), 1993, pp. 187-194
An aqueous extract of the stems and leaves of Portulaca oleracea aboli
shes the twitch contraction of the directly stimulated rat hemidiaphra
gm preparation. The effects of the extract mimic qualitatively the act
ion of potassium oxalate - a known constituent of Portulaca oleracea -
on the diaphragm. Removal of K+ ions from the methanol extract by pas
sing it through a cation exchange resin reduced the inhibitory effect
of the extract. There was a positive correlation between the concentra
tion of K+ ions in the extract and the effects of potassium chloride o
f similar molarity. It is concluded that the K+ ion content of Portula
ca oleracea is at least partly responsible for the relaxant effect obs
erved on the isolated rat diaphragm.