Complex sentence: Brinda Karat, a senior leader of the Communist Party of India (Marxist) was involved with the protesters and was told by disgruntled workers that animal parts were used in the manufacture of some medicines.
Split into simpler sentences: Brinda Karat, a senior figure in the Communist Party of India (Marxist) was involved with the protesters. They told her that animal parts were used in the manufacture of some medicines.