Bioactive bicyclic aromatic compounds and pharmaceutical/cosmetic compositions comprised thereof

A bicyclic aromatic compound having the structural formula (I):

• ##STR6## in which R.sub.1, is a radical --CO--R.sub.10, R.sub.3 is a hydrogen atom or a lower alkyl radical, R.sub.2 and R.sub.4 together form, with the benzene ring from which they depend, a naphthalene ring member, in which R.sub.7 is as defined below;
• R.sub.5 is a hydrogen atom, a halogen atom, a lower alkyl radical, an NO.sub.2 radical, a hydroxyl radical, a radical --OR.sub.7, or a radical:
• ##STR7## in which R.sub.7, R.sub.13 and R.sub.14 are as defined below;
• X is --O--, or --S(O).sub.t --, wherein t is as defined below;
• Y and Z, which may be identical or different, are each --CR.sub.13 R.sub.14 --, --O-- or --S(O).sub.t --, with the proviso that Y and Z cannot simultaneously be an oxygen atom and cannot simultaneously be a radical --S(O).sub.t --, wherein t, R.sub.13 and R.sub.14 are as defined below;
• R.sub.7 is a lower alkyl radical;
• R.sub.10 is ##STR8## a radical --O--R.sub.11, wherein R.sub.11 is a hydrogen atom, a linear or branched alkyl radical having from 1 to 20 carbon atoms, an alkenyl radical, a mono- or polyhydroxyalkyl radical, an optionally substituted aryl or aralkyl radical, a sugar radical, or an amino acid residue or peptide residue;
• R.sub.13, and R.sub.14 are each a hydrogen atom, or a lower alkyl radical;
• t is 0, 1 or 2;
• or a pharmaceutically/cosmetically acceptable salt or optical or geometric isomer thereof.