Smooth Muscle Relaxing Compounds from Dodonaea viscosa ⁵

Abstract

Bioassay-directed fractionation of the chloroform-methanol (1:1) extract of Dodonaea viscosa (L.) Jacq. (Sapindaceae) resulted in the isolation of four active spasmolytic principles: sakuranetin (1), 6-hydroxykaempferyl 3,7-dimethyl ether (2)hautrivwic acid(3), and ent-15,16-epoxy-9 αH-labda-13(16)14-diene-3β,8α-diol (4). All the isolated compounds elicited a concentration-dependent inhibition of the spontaneous and electrically-induced contractions of guinea-pig ileum. Sakuranetin and the ent-labdane inhibited the ileum contractions evoked by acetylcholine (Ach), histamine, and barium chloride. In addition, both substances were capable of relaxing contractions of rat uterus induced by Ca²⁺ in K⁺-depolarizing solution, displacing to the right the concentration-response curves to Ca²⁺. These results suggest that sakuranetin and ent-15,16-epoxy-9αH-labda-13(16)14-diene-3β,8α-diol produce an interference with calcium metabolism in smooth muscle cells. The spasmolytic activity exhibited by the active principles from D. viscosa, provides the pharmacological basis for the traditional use of the plant as an antispasmodic agent.

Key words

Dodonaea viscosa - Sapindaceae - sakuranetin - 6-hydroxykaempferyl 3,7-dimethyl ether - hautriwaic acid - ent-15,16-epoxy-9αH-labda-13(16)14-diene-3β,8α-diol - smooth muscle relaxation - spasmolytic effect - calcium blocker - isolated guinea-pig ileum - rat uterus