INDENOINDOLE COMPOUNDS

Compounds of formulae (IA) and (IB), wherein R is hydrogen or a lower alkyl group, R?1 and R?2 are independently selected from hydrogen or a lower alkyl group, R?3, R?4 and R?6 are independently selected from hydrogen, halogen or a lower alkyl group, R?5 is hydrogen, hydroxy, halogen, a lower alkyl group, a lower alkoxy group, a mono- or di-lower alkylamino group, NH2? or NR?11 COR?12, R?7, R?8, R?9 and R?10 are independently selected from hydrogen, hydroxy, a lower alkyl group, a lower alkoxy group, a mono- or di-lower alkylamino group, NH2? or NR?11 COR?12, R?11 is a hydrogen or a lower alkyl group, R?12 is a lower alkyl group, with the proviso that when R is hydrogen then at least one of the substituents R?1 to R?10 is not hydrogen, or a salt thereof, are useful as antioxidants, within the medical and non-medical field, and that when R is hydrogen, methyl or neopentyl in formula (IA), then at least one of R?1 to R?10 is not hydrogen. Many of the compounds of formulae (IA) and (IB) are new and various methods for preparing them are described.