Investigating algae in the real world

This evolution involved only a very small number of species. In the oceans, three ‘families’ coexist: green, red and brown, but only the first one left the aquatic environment and most of the red and brown species have not even colonised freshwaters. Thus, red and brown algae (macro-and microalgae) have no terrestrial equivalent and their metabolites are almost all originals. 

Scientists will find the largest chemodiversity in the marine environment with the best chance to find new models of molecules with new biological activities. Microalgae, at the origin of life on earth, present across the seas, oceans and freshwater sources, are a source of compounds of interest and represent a world to discover. They represent hundreds of thousands of species according to estimates. These are chlorophyll photoautotrophic organisms that appeared billions of years ago. Microalgae may be pelagic or benthic and they are defined as undifferentiated unicellular or multicellular organisms and may belong to the suborder of eukaryotes or prokaryotes such as cyanobacteria. These microorganisms play a major role in our planet and are gathered around a physiological coherence, oxygenic photosynthesis. 

The use of molecules derived from marine organisms for therapeutic or cosmetic uses is still limited. With few exceptions, and unlike the terrestrial environment, there is virtually no oral tradition or any traditional medicine or pharmacopeia regarding the use of molecules from the marine environment. The few known rare examples are in the Far East, in some Pacific islands and in some Scandinavian sources. Natural substances isolated from marine organisms, from prokaryotes or eukaryotes are often characterised by the presence of chemical elements or structures rarely observed or even unknown in the terrestrial environment. It is true for primary and secondary metabolites.