Through the photosynthetic activity, microalgae process more than 25% of annual inorganic carbon dissolved in oceans into carbohydrates that ultimately, serve to feed the other levels of the trophic networks. Besides, microalgae synthesize bioactive molecules such as pigments and lipids that exhibit health properties. In addition, abiotic stresses, such as high irradiance, nutrient starvation, UV irradiation, trigger metabolic reorientations ending with the production of other bioactive compounds such as ω-3 fatty acids or carotenoids. Traditionally, these compounds are acquired through the dietary alimentation. The increasing, and often unsatisfied, demand for compounds from natural sources, combined with the decrease of the halieutic resources, forces the search for alternative resources for these bioactive components. Microalgae possess this strong potential. For instance, the diatom Odontella aurita is already commercialized as dietary complement and compete with fish oil for human nutrition. In this contribution, the microalga world is briefly presented. Then, the different types of biologically active molecules identified in microalgae are presented together with their potential use. Due to space limitation, only the biological activities of lipids and pigments are described in details. The contribution ends with a description of the possibilities to play with the environmental constrains to increase the productivity of biologically active molecules by microalgae and by a description of the progresses made in the field of alga culturing.

Dunaliella tertiolecta (DT) was chemically investigated to isolate molecules inhibiting cancer cell proliferation and inducing apoptosis in vitro. The potency to inhibit cell growth was used for the bio-guided fractionation and isolation of active compounds using chromatographic techniques. The DT dichloromethane extract exhibited a strong anti-proliferative activity on MCF-7 and LNCaP cells, and was further fractionated and sub-fractionated by RP-HPLC. High resolution mass spectrometry and spectrophotometric analysis unequivocally identified violaxanthin as the most antiproliferative molecule present in DT DCM extract. Violaxanthin purified from DT induced MCF-7 dose-dependent growth inhibition in continuous and discontinuous treatments, at concentrations as low as 0.1 µg·mL⁻¹ (0.17 µM). Phosphatidylserine exposure, typical of early apoptosis, was observed after 48 h treatment at 8 µg·mL⁻¹ (13.3 µM) but no DNA fragmentation, characteristic of late apoptosis steps, could be detected even after 72 h treatment at 40 µg·mL⁻¹ (66.7 µM). Taken together, our results demonstrate the strong antiproliferative activity of violaxanthin on one human mammary cancer cell line, and suggest that studying the pharmacology of violaxanthin and pharmacomodulated derivatives on cancer cells may allow potent antiproliferative drugs to be obtained.

Anthocyanins, a class of flavonoid compounds responsible for the vibrant colors of many fruits and vegetables, have received considerable attention in recent years due to their potential health benefits. This review, focusing on evidence from both in vitro and in vivo studies, provides a comprehensive overview of the current state of knowledge regarding the health-promoting properties of anthocyanins. The chemical structure and diversity of anthocyanins, their bioavailability, and their mechanisms of action at the cellular and molecular level are examined. Research on the antioxidant, anti-inflammatory, anticancer, and neuroprotective effects of anthocyanins is critically reviewed. Special emphasis is placed on the role of anthocyanins in the prevention and treatment of chronic diseases such as cardiovascular diseases, diabetes, and neurodegenerative diseases. This review also discusses the challenges of translating in vitro findings to in vivo and highlights the importance of considering dose, bioavailability, and metabolism when assessing the therapeutic potential of anthocyanins. This review concludes with the identification of gaps in current research and suggestions for future directions for anthocyanin studies, including the need for more long-term clinical trials and investigations into potential synergistic effects with other phytochemicals. This comprehensive analysis highlights the promising role of anthocyanins in promoting human health and provides valuable insights for researchers, health professionals, and the nutraceutical industry. This study provides new insights, as it comprehensively investigates the dual anti-inflammatory and anticancer effects of anthocyanins in both in vitro and in vivo models. By uncovering the biological properties of anthocyanins from a variety of natural sources, this research not only expands our knowledge of the action of these compounds at the cellular level, but also enhances their clinical relevance through in vivo validation. Furthermore, the innovative use of anthocyanins may lead to important advances in their therapeutic application in the future.