Aromatic polyenic compounds and pharmaceutical/cosmetic compositions comprised thereof

An aromatic polenic compound having the structural formula (I):

• ##STR4## in which R.sub.1 is a --CH.sub.3 radical, a radical --CH.sub.2 --O--R.sub.9, a radical --CH.sub.2 --O--CO--R.sub.10, or a radical --CO--R.sub.11, wherein R.sub.9, R.sub.10, and R.sub.11 are as defined below;
• R.sub.2 is a hydrogen atom or a lower alkyl radical having 1 to 6 carbon atoms;
• R.sub.3 is a hydrogen atom or a lower alkyl radical having 1 to 6 carbon atoms;
• R.sub.5 is a hydrogen atom or a lower alkyl radical having 1 to 6 carbon atoms;
• R.sub.7 and R.sub.8 independently are each (i) a hydrogen atom, (ii) a linear or branched alkyl radical having from 1 to 20 carbon atoms, (iii) a cycloaliphatic radical selected from the group consisting of 1-methylcyclohexyl and 1-adamantyl, (iv) a radical --O--CH.sub.2 --O--CH.sub.2 --CH.sub.2 --O--CH.sub.3, (v) a radical --O--R.sub.13, or (vi) a radical --S(O).sub.n R.sub.13, wherein R.sub.13 and n are as defined below, R.sub.4 and R.sub.6 together form, with the carbon atoms from which they depend and with the adjacent benzene ring, a naphthalene ring, and at least one of R.sub.7 and R.sub.8 has the above definition (ii) or (iii);
• R.sub.9 is a hydrogen atom or a lower alkyl radical having 1 to 6 carbon atoms;
• R.sub.10 is a lower alkyl radical having 1 to 6 carbon atoms;
• R.sub.11 is (a) a hydrogen atom, (b) a lower alkyl radical having 1 to 6 carbon atoms, (c) a radical of formula:
• ##STR5## in which R' and R" independently are each a hydrogen atom, a lower alkyl radical having 1 to 6 carbon atoms, a mono- or polyhydroxyalkyl radical respectively having 2 to 3 carbon atoms or 3 to 6 carbon atoms containing 2 to 5 hydroxyl groups, or an optionally substituted phenyl radical which if substituted, is substituted with at least one halogen atom, hydroxyl or nitro group, or (d) a radical --OR.sub.12, wherein R.sub.12 is a hydrogen atom, a linear or branched alkyl radical having from 1 to 20 carbon atoms, an alkenyl radical having 2 to 5 carbon atoms and at least one site of ethylenic unsaturation, a mono- or poly-hydroxyalkyl radical respectively having 2 to 3 carbon atoms or 3 to 6 carbon atoms and 2 to 5 hydroxyl groups, or an optionally substituted phenyl or radical benzyl or pheneyl radical wherein, if substituted, are substituted by at least one halogen atom, hydroxyl or nitro functional group;
• R.sub.13 is a hydrogen atom or a linear or branched alkyl radical having from 1 to 20 carbon atoms;
• and n is an integer equal to 0, 1 or 2;
• or a pharmaceutically/cosmetically acceptable salt or optical or geometric isomer thereof.