Microalgae form a group of diverse oceanic or clean water microorganisms. They are unicellular or multicellular, eukaryotic or prokaryotic microscopic organisms. Thanks to their diversity and speed reproduction, microalgae represent an untapped source that offers great opportunities for the isolation of original natural molécules with putative interest for food, health or biotechnological applications.In the recent years, microalgae have been the subject of intensive investigation notably for the discovery of anti-proliferative and candidate anticancer biomolecules. In this context, the present work aimed to extracting and purifying bioactive molecules from the microalgae N. gaditana acting on the cytoskeleton and more particularly on the microtubule network.A combined approach based on analytical chemistry and biological screening led us to extract and identify three families of substances: lipids (Triglycerides and fatty acids), pigments and phthalates. The first two families are known for their presence in microalgae. However, this study is the first one to show the presence of phthalates in microalgae, particularly in the N. gaditana specie.We then investigated the effect of a pure phthalate (Benzyl butyl phthalate: BBP) on the microtubules network of HeLa cells. This compound revealed to induce alterations of microtubules and that this effect became more important in the presence fatty acid (linoleic acid). This effect was associated with an induction of formation of lipid droplets. We also invastigated the impact of a type of pigment, Pheophorbide A, on cell morphology and on the microtubule network. This molecule appeared to have a direct or indirct effect on the polymerization of tubulin.Finally, we evaluated the interest of a biotechnological process based on the solubilization of hydrophobic phthalate and pheophorbide A in water using a synthetic triblock molecules studied in water by a synthetic triblock pMeOx-p(THF)-pMeOx polymer. This process revealed a significant gain of activity of these two molecules.Altogether, our results show that N. gaditana contains active biomolecules with putative interest to block cell division. They may be in the future a candidate molecules notably to fight cancer.