Chlorella vulgaris strain K-1801 come fonte di mycosporine-like amino acids

This study has been conducted at the Edmund Mach Foundation, in the frame of the AlgaeCeuticals project, which aims at identifying new compounds of industrial interest, especially for cosmetics and nutraceuticals, within the group of green algae. In particular, this study focused on the identification and subsequent characterization of a molecule belonging to the group of the mycosporine-like amino acids (MAAs). These compounds are small secondary metabolites of considerable industrial interest. In fact, they have the ability to strongly absorb the UV-radiation, which confer to them many possible industrial uses. They are widely distributed in nature, especially in microorganisms, including green algae. The study started from the metabolic profiling of an extract of Chlorella vulgaris strain K-1801 with LC/DAD/MS. The profiling revealed the presence of a compound with strong absorbance in the UV range, having λmax = 322 nm. Afterwards, specific analytic methods were developed for the extraction and LC/DAD/MS characterization of the compound of interest. The chemical characterization of the compound was carried out by the determination of the its molecular mass, performed by high-resolution mass analysis, which allowed the identification of the brute formula: C11H17NO7 (monoisotopic mass 275.1005 Da). Then, in order to elucidate its chemical structure, mass fragmentation and nuclear magnetic resonance studies were carried out. These studies allowed only a partial elucidation of the chemical structure of the molecule. By combining all the data, was hypothesized that the compound could be 2-{[4,5-dihydroxy-5-(hydroxymethyl)-2-methoxy-3-oxocyclohex-1-en-1-yl]amino}propanoic acid. If confirmed, this molecule represents a new compound of the MAA family. Furthermore, stimulation tests were conducted, in order to assess the effect of photo-oxidative and osmotic stresses on the cellular growth and on the biosynthesis of the target molecule. Finally, genetic analyses were performed on the studied strain, which revealed that the producing organism belongs to the class of Chlorophyceae.