The invention provides extracts of the microalga Aphanizomenon Flos Aquae Aquae Ralfs ex Born. & Flah. Var. flos aquae (AFA Klamath) and biologically active components thereof, in particular AFA-phycocyanins, determined as the complex c-phycopcyanin/phycoerythrocyanin (including the chromophore phycoviolobilin), AFA-phytochrome and mycosporine-like aminoacids (MAAs), nutritional, cosmetic and pharmaceutical compositions containing the same, for use in the prophylaxis or treatment of diseases, disturbances or conditions involving acute or chronic inflammation and oxidative degeneration of body cells or tissues or uncontrolled cell proliferation.