Potential metal chelating ability of mycosporine-like amino acids: a computational research

Novel synthetic UV screen compounds inspired in mycosporine-like amino acids (MAAs): Antioxidant capacity, photoprotective properties and toxicity

The combination of environmental stress on the ozone layer, climate change and a greater sun exposure due to outdoor habits has led to an increase in skin cancer cases and other health issues related with UV radiation. Researchers are searching for new alternative UV filters that could protect our skin from the deleterious effects of UV radiation while also presenting low toxicity and biodegradable character (unlike the UV filters currently available in the market). In this work, two compounds inspired in the natural oxo-mycosporine-like amino acids (MAAs) have been synthesized and their antioxidant and photoprotective properties, as well as their in vitro and in vivo toxicity effects were evaluated. Both compounds featured a strong UV-B absorption together with a high antioxidant capacity, close to 50 μmol TE g-1 DW in the ABTS assay. Compound 1 presented an absorption peak at 285-300 nm, whereas compound 2 showed a wider band with a peak around 295-305 nm and two shoulders at 318 and 342 nm. The addition of 5 % of compound 2 to galenic formulas increased the photoprotection, reaching SPF values of 4. Both compounds were stable under UV radiation exposure. Regarding toxicity, the synthetic compounds did not show cytotoxic activity against healthy human cell lines or significant toxicity over zebrafish embryos. Compound 1 showed a complete lack of toxicity over zebrafish, although compound 2 showed slight, not-significant effects on viability, hatching, pericardial stability or body axis formation over 5 mg mL-1. Moreover, compound 1 presented relatively antitumoral activities against HCT-116 cells (selective index:1.49). The relevant antioxidant and photoprotective ability together with the great advantage provided by the reduced toxicity to health cells or zebrafish embryos, make these compounds promising candidates to be exploited as functional ingredients with specific applications in the biotechnological or pharma sector.

Argentine squid (Illex argentinus): A source of mycosporine-like amino acids with antioxidant properties

Here we report on the occurrence of mycosporine-like amino acids (MAAs) in the Argentine shortfin squid, Illex argentinus, the second fishery resource mostly exploited in the Argentinean continental shelf. The total content of four MAAs was evaluated by reverse-phase-HPLC in different tissues (eyes, skin, liver, and gonads). Also, the antioxidant activity of crude extracts was assessed by in-vitro determinations: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu, and ferrous ion-chelating capacity assays. The content of MAAs was found to be almost ten times higher in female gonads than in other tissues (11,89 ± 0,56 mg/g dry weight). Extracts from skin, female gonads and eyes, exhibit higher antioxidant activity than the reference compounds ascorbic acid and TROLOX. Overall, Argentine squid waste is a promising potential source of MAAs with antioxidant and UV photoprotective properties, which could bear interest in food, cosmetic and pharmaceutical industries, thus encouraging maximal and sustainable use of fishing resources.

Iron Content, Iron Speciation and Phycocyanin in Commercial Samples of Arthrospira spp

Cyanobacteria are characterized by high iron content. In this research, we collected ten commercial samples of Arthrospira spp. sold as food supplement to determine iron content and assess whether iron speciation showed variability among samples and changed respect to A. platensis grown in controlled conditions. Particular attention was also paid to phycocyanin, as an iron-binding protein. In six of the ten samples, 14 essential and non-essential trace elements were analysed using ICP-MS. Iron content measured in samples using atomic absorption spectrometry (AAS) varied from 353 (sample S5) to 1459 (sample S7) µg g^-1 dry weight and was in the range of those reported by other authors in commercial supplements. Iron speciation was studied using size exclusion chromatography followed by the analysis of the collected fraction for the determination of iron by AAS and for protein separation using SDS-PAGE. Overlapping chromatographic profiles were obtained for total proteins, phycocyanin and iron, although quantitative differences were evidenced among the samples analysed. In most samples, iron was mainly bound to ligands with high molecular mass; however, in four samples iron was also bound to ligands with low molecular mass. In fractions containing the most relevant iron burden, the principal protein was phycocyanin, confirming its role as an iron-binding protein in commercial samples.