Rubber compound for preparing pneumatic tyre parts comprising a cross-linkable unsaturated chain polymer base, a filler, a vulcanization system and one or more antioxidant agents. The antioxidant agents comprise functionalized lignin with –OR groups, where R is a terpene group with a total number of carbon atoms of between 6 and 16. The –OR groups deriving from the functionalization of 10 to 60% of the lignin phenolic hydroxyl groups.