Water extracts of plants are used since ancient times even though their properties were not fully investigated. These plants are rich in many healing properties, so a large part of today's research is devoted just to them. All water extracts used in this experiment were taken from wild breeding species of Centaurea ragusina, C. salonitana, C. alba, C. solstitialis, C. scabiosa, C. rupestris, C. jacea, C. calcitrapa ,C. spinosociliata. The aim was to investigate the chemical composition and also the biological activity of water extracts: antioxidant potential and inhibition of the enzyme acetylcholinesterase and butyrylcholinesterase. A few analysis of the chemical composition of water extracts have proven the presence of phenolic compounds as well as the identification of the same in plants of the genus Centaurea. Today the phenolic compounds attract a huge attention because of the antioxidant potential. The antioxidant potential is a key factor in the defense of the organism from diseases. Results of testing DPPH radicals scavenging ability and the extracts reducing power, tested by FRAP method, showed low atioxidant potential of Centaurea water extracts. Also the water extracts of Centaurea species along with pure phenolic compounds showed a low inhibitiory activity on acetylcholinesterase and butyrylcholinesterase.