Lipids from the proliferative macroalgae Ulva armoricana (Chlorophyta) and Solieria chordalis (Rhodophyta) from Brittany, France, were investigated. The total content of lipids was 2.6% and 3.0% dry weight for U. armoricana and S. chordalis, respectively. The main fractions of S. chordalis were neutral lipids (37%) and glycolipids (38%), whereas U. armoricana contained mostly neutral lipids (55%). Polyunsaturated fatty acids (PUFA) represented 29% and 15% of the total lipids in U. armoricana and S. chordalis, respectively. In both studied algae, the phospholipids were composed of PUFA for 18%. In addition, PUFA were shown to represent 9% and 4.5% of glycolipids in U. armoricana and S. chordalis, respectively. The essential PUFA were 16:4n-3, 18:4n-3, 18:2n-3, 18:2n-6, and 22:6n-3 in U. armoricana, and 20:4n-6 and 20:5n-3 in S. chordalis. It is important to notice that six 2-hydroxy-, three 3-hydroxy-, and two monounsaturated hydroxy fatty acids were also identified and may provide a chemotaxonomic basis for algae. These seaweeds contained interesting compounds such as squalene, α-tocopherol, cholest-4-en-3-one and phytosterols. The antiproliferative effect was evaluated in vitro on human non-small-cell bronchopulmonary carcinoma line (NSCLC-N6) with an IC₅₀ of 23 μg/mL for monogalactosyldiacylglycerols isolated from S. chordalis and 24 μg/mL for digalactosyldiacylglycerols from U. armoricana. These results confirm the potentialities of valorization of these two species in the fields of health, nutrition and chemotaxonomy.

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 µg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC₅₀ of 4.1 and 17.2 µg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively.

As the association of marine animals with bacteria has become more commonly recognized, researchers have increasingly questioned whether these animals actually produce many of the bioactive compounds originally isolated from them. Bacteriocins, ribosomally synthesized antibiotic peptides, constitute one of the most potent weapons to fight against pathogen infections. Indeed, bacteriocinogenic bacteria may prevent pathogen dissemination by occupying the same ecological niche. Bacteriocinogenic strains associated with marine animals are a relevant source for isolation of probiotics. This review draws up an inventory of the marine bacteriocinogenic strains isolated from animal-associated microbial communities, known to date. Bacteriocin-like inhibitory substances (BLIS) and fully-characterized bacteriocins are described. Finally, their applications as probiotics in aquaculture are discussed.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting. A method to extract and purify marennine has been developed, but its chemical structure could hitherto not be resolved. For decades, H. ostrearia was the only organism known to produce marennine, and can be found worldwide. Our knowledge about H. ostrearia-like diatom biodiversity has recently been extended with the discovery of several new species of blue diatoms, the recently described H. karadagensis, H. silbo sp. inedit. and H. provincialis sp. inedit. These blue diatoms produce different marennine-like pigments, which belong to the same chemical family and present similar biological activities. Aside from being a potential source of natural blue pigments, H. ostrearia-like diatoms thus present a commercial potential for aquaculture, cosmetics, food and health industries.