CROTON-RUIZIANUS - PLATELET PROAGGREGATING ACTIVITY OF 2 NEW PREGNANEGLYCOSIDES

The MeOH extract of the aerial parts of Croton ruizianus afforded two new pregnane glycosides 1 and 2, together with the morphinandienone al kaloids flavinantine (3) and O-methylflavinantine (4). Their structure s were elucidated by NIR experiments including H-1-H-1 (1D TOCSY and 2 D DQF-COSY) and H-1-C-13 (HSQC, HMBC) spectroscopy. The proaggregating activity of the MeOH extract and the isolates were evaluated. Althoug h the MeOH extract and pregnane glycosides (at different doses) were f ound to promote platelet aggregation, flavinantine (3) and O-methylfla vinantine (4) showed only slight activity. The ability of the MeOH ext ract and the four compounds to act synergistically with thrombin was a lso evaluated. All the tested compounds were successful in augmenting the aggregating effect of thrombin, although to different degrees.