Antioestrogenic effect of trans-dehydrocrotonin, a nor-clerodane diterpenefrom Croton cajucara Benth. in rats

This study examined trans-dehydrocrotonin (t-DCTN), a nor-clerodane diterpe ne isolated from the Brazilian medicinal plant Croton cajucara Benth., for a possible antioestrogenic activity using immature rats as a model system f or bioassay of oestrogen, and for an antiimplantation effect in regularly c ycling rats of proven fertility, In the antioestrogen test, t-DCTN (25 and 50 mg/kg) effectively prevented oestrogen-induced increases of uterine wet weights. In addition, the vaginal openings provoked by oestrogen were compl etely prevented by t-DCTN, However, blastocyst-implantation was only insign ificantly affected in t-DCTN pretreated animals, These results suggest that t-DCTN may be an antioestrogen and warrants further studies with regard to its mechanism of action. Copyright (C) 1999 John Whey & Sons, Ltd.