Aglycons

Aglycon compounds corresponding to the general formula IV below:

• ##STR34## in which:
• R.sub.1, R.sub.2, R.sub.3, and R.sub.5, which can be identical or different, represent a hydrogen atom or a group OH, OMetal or OR.sub.4, R.sub.4 being a substituted or unsubstituted C.sub.1 to C.sub.6 alkyl group,
• R represents a hydrogen atom or a group COCH.sub.2 R', R' being hydrogen or an alkyl, hydroxyl, alkoxy or aryl group,
• R.sub.6 and R.sub.7, which are always different, represent either a hydrogen atom or an OH group, and
• R.sub.8, which is located on the A ring in the compound of formula IV, represents a hydrogen atom or the group CH.sub.3 CO--, with the proviso that:
• (a) R.sub.1, R.sub.2 and R.sub.3 are never simultaneously hydrogen when R.sub.7 and R.sub.8 represent the hydrogen atom and R is the group COCH.sub.2 R', and
• (b) if R.sub.1, R.sub.2, R.sub.3 and R.sub.6 are hydrogen, R.sub.5 is other than hydrogen and OCH.sub.3.