The abortifacient effects from the seeds of Coix lachryma-jobi L. var. ma-yuen Stapf.

This study evaluated the abortifacient effects of the extracts of seeds of Coix lachryma-jobi L. var. ma-yuen Stapf (adlay) in pregnant rats. Pregnant rats were treated with oral administration of adlay seed extracts on d 6 of pregnancy and their fetuses were examined for growth and malformations on d 20 of pregnancy. Following oral administration of 1 g/kg body weight of water extracts but not methanolic extracts, fetal resorptions were significantly increased and mortality of postimplantation was increased. There were no significant differences in the uterine and fetal weight compared to control. Fetal malformations were not observed in the adlay seed extracts-treated pregnant rats. The contractile activity of uteri isolated from rats on d 20 of pregnancy was assessed. The spontaneous uterine contractions were significantly enhanced in rats treated with water extracts of adlay seeds (1 g/kg body weight). Immunoblotting of uteri from rats treated with water extracts of adlay seeds demonstrated an induction of cyclooxygenase-2 (COX-2) protein expression. The water extracts of adlay seeds also enhanced extracellular signal-regulated protein kinase (ERK) 1/2 phosphorylation and protein kinase C (PKC)-alpha translocation from cytosolic to particulate fractions in uteri. These results indicate that the water extracts of adlay seeds are capable of inducing embryotoxicity and enhancing uterine contractility during pregnancy. The enhanced activities of PKC-alpha, ERK1/2, and COX-2 may contribute to these responses.