Chalcones

A compound selected from those having the formula (I):

• ##STR10## in which:
• R.sub.1 represents a hydrogen atom or a lower alkyl radical,
• X represents:
• an oxygen or sulfur atom,
• a CH.sub.2 group, on condition that, in this case,
• Y represents an oxygen or sulfur atom,
• Y represents:
• a single bond or a group CR.sub.7 R.sub.8, where R.sub.7 and R.sub.8, which may be identical or different, represent, independently of one another, a hydrogen atom, a lower alkyl group, a phenyl group, a substituted phenyl group, a phenylalkyl group or a substituted phenylalkyl group,
• an oxygen or sulfur atom, on condition that, in this case, X represents a CH.sub.2 group,
• Z represents (1) a hydrogen atom, and in this case T also represents a hydrogen atom, or (2) Z forms with T a link --CH.sub.2).sub.n --(CH(E)-- or (CH.sub.2).sub.n --CH(CH.sub.2 E') with being n an integer equal to 0, 1, 2 or 3, which, in this case Z is carried by a carbon adjacent to the carbon carrying the acyl group, and E or E' represents a hydrogen atom, a lower alkyl group or a phenyl, thienyl or substituted phenyl group,
• the term "substituted" in relation to the terms phenyl and phenylalkyl in the definition of R.sub.7 and R.sub.8 and E and E' meaning that these groups may be substituted with one or more substituents selected from lower alkyl, lower alkoxy, halogen, trifluoromethyl or hydroxyl,
• R.sub.2, R.sub.3 and R.sub.4, which may be identical or different, represent, independently of one another, a hydroxyl or lower alkoxy group or a lower alkyl group,
• its enantiomers, epimers and diastereoisomers as well as, when R.sub.1 represents a hydrogen atom or when at least one of the groups R.sub.2, R.sub.3 and R.sub.4 represents a hydroxyl group, its addition salts with a pharmaceutically acceptable base,
• on the lower alkyl or lower alkoxy being understood to mean linear or branched groups comprising from 1 to 6 carbon atoms.