SMOOTH-MUSCLE RELAXING COMPOUNDS FROM DODONAEA-VISCOSA

Bioassay-directed fractionation of the chloroform-methanol (1:1) extra ct of Dodonaea viscose (L.) Jacq. (Sapindaceae) resulted in the isolat ion of four active spasmolytic principles: sakuranetin (1), 6-hydroxyk aempferyl 3,7-dimethyl ether (2) hautriwaic acid(3), and ent-15,16-epo xy-9 alpha H-labda-13(16)14-diene-3 beta,8 alpha-diol (4). All the iso lated compounds elicited a concentration-dependent inhibition of the s pontaneous and electrically-induced contractions of guinea-pig ileum. Sakuranetin and the ent-labdane inhibited the ileum contractions evoke d by acetylcholine (Ach), histamine, and barium chloride. In addition, both substances were capable of relaxing contractions of rat uterus i nduced by Ca2+ in K+-depolarizing solution, displacing to the right th e concentration-response curves to Ca2+. These results suggest that sa kuranetin and ent-15,16-epoxy-9 alpha H-labda-13(16)14-diene-3 beta,8 alpha-diol produce an interference with calcium metabolism in smooth m uscle cells. The spasmolytic activity exhibited by the active principl es from D. viscosa, provides the pharmacological basis for the traditi onal use of the plant as an antispasmodic agent.