Indenoindolone compounds

A compound selected from those of formula (I):

• 12
• wherein:
• R represents hydrogen, linear or branched (C1-C6)alkenyl or linear or branched (C1-C6)alkyl optionally substituted by carboxy or by a group of formula —NRaRb wherein each of Ra and Rb, which may be identical or different, represents hydrogen or linear or branched (C1-C6)alkyl, or form together with the nitrogen atom carrying them a nitrogen-containing heterocycle,
• each of R1, R2, R3, R4, R5, R6, R7 and R8, which may be identical or different, represents hydrogen, linear or branched (C1-C6)alkyl, linear or branched (C1-C6)alkenyl, hydroxy, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)alkenyloxy, aryl-(C1-C6)alkyl in which the alkyl moiety is linear or branched, aryl-(C1-C6)alkoxy in which the alkoxy moiety is linear or branched, carboxy, linear or branched (C1-C6)-acyloxy, or arylcarbonyloxy,
• or one of R1 to R8 forms with an adjacent one R1 to R8 a (C1-C2)alkylenedioxy group,
• its optical isomers when they exist, and addition salts thereof with a pharmaceutically acceptable acid or base,
• with the proviso that:
• when R does not represent hydrogen, then at least one of R1 to R8 represents hydroxy or linear or branched (C1-C6)acyloxy,
• and the compounds of formula (I) are other than indeno[1,2-b]indol-10(5H)-one,
• it being understood that the term “aryl” is understood to mean “phenyl”, “biphenylyl”, “naphthyl” or “tetrahydronaphthyl”, each of those groups being optionally substituted by one or more identical or different atoms or groups selected from halogen, linear or branched (C1-C6)alkyl, hydroxy, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)polyhaloalkyl, amino (optionally substituted by one or more linear or branched (C1-C6)alkyl), nitro, linear or branched (C1-C6)acyl and (C1-C2)alkylenedioxy.