Silvaglins and related 2,3-secodammarane derivatives - unusual types of triterpenes from Aglaia silvestris

The 2,3-secodammarane aglasilvinic acid and the related silvaglines with a five-membered A-ring represented typical chemical features of A. silvestris accompanied by a series of 3,4-secodammaranes, a pregnane steroid and two sesquiterpenes. Comparison of six different plant collections revealed the existence of two chemo-types characterised either by 20R or 20S configuration in all major triterpenes.