Overall, around 15,000 pharmacologically active compounds have been isolated from marine species, many of which are structurally unique and absent in terrestrial organisms. Extremophiles are organisms that have developed specific adaptations that allow them to survive prohibitive conditions for humans. The purpose of this work is to combine these two aspects, investigating the associated microbial community with 2 types of filtering organisms, Arctic bivalve molluscs (Margaritifera margaritifera) (Fig.1) and Antarctic poriferous (Calyx arcuaria, Haliclona virens, Haliclona (Rhizoniera) dancoi, Haliclona rudis), to take advantage of potential developed by extremophiles, analyze the secondary metabolites produced and assess the presence of pharmacological properties. In specific, possible antiproliferative, antiparasitic and antimicrobial activities were been evaluated against, most common cancer cell lines, parasitics and pathogenic bacteria.