Abstract
Macroalgae are sources of bioactive compounds that are interesting from both a chemical and a medical point of view. Although their use in biomedicine has increased significantly in recent years, tests conducted to date have been mostly related to species from temperate latitudes, with the potential application of Antarctic biodiversity being minor. The wide variety of algae species present on Antarctic coastal areas can be a source of new antioxidants. Bearing this in mind, the brown macroalgae Desmarestia antarctica (DA) and the red Iridaea cordata (IC) were selected for the preparation of aqueous extracts with the aim of analyzing their antioxidant activity. This analysis was performed by determining reducing power, total phenolic content, and 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity. Furthermore, both extracts were employed to synthesize gold and silver nanoparticles. The nanomaterials were fully characterized by means of UV-Visible spectroscopy, transmission electron microscopy, Z potential measurements, and Fourier transform infrared spectroscopy, which confirmed the formation of stable, spherical nanoparticles with mean diameters of 13.7 ± 3.1 and 17.5 ± 3.7 nm for Ag@DA and Ag@IC and 12.6 ± 1.9 and 12.3 ± 1.6 nm for Au@DA and Au@IC. Antioxidant assays were performed after the synthesis of the nanomaterials to evaluate their possible synergistic effect with the extracts. The results suggest that polysaccharides and proteins may play a key role in the process of reduction and stabilization. Finally, for the sake of comparison, the results obtained for the Antarctic macroalgae Desmarestia menziesii and Palmaria decipiens have also been considered in the present work.
Highlights
The Antarctic Ocean is characterized by high levels of biodiversity, both in fauna and flora [1,2]
For the sake of comparison, the results obtained for the Antarctic macroalgae Desmarestia menziesii and Palmaria decipiens have been considered in the present work
Following our research on the synthesis of nanomaterials by green methods, this study evaluates both the potential to synthesize gold and silver nanoparticles and the antioxidant activity of two Antarctic macroalgae, Desmarestia antarctica (DA) and Iridaea cordata (IC), which belong to two of the most dominant taxonomic groups in the Antarctic and sub-Antarctic ecoregion, the Orders Desmarestiales and Gigartinales, respectively [10]
Summary
The Antarctic Ocean is characterized by high levels of biodiversity, both in fauna and flora [1,2]. Macroalgae are sources of bioactive compounds that are interesting from both a chemical and a medical point of view due to their relevant effects on human health [6,7]. The body of knowledge about algal applications in biomedicine has increased significantly in recent years, this approach is mostly related to species from temperate latitudes [8], and the number of studies on the potentiality of the biodiversity of Antarctic species still low [9]. As a result of the unique environment that Antarctic organisms need to face, we hypothesize that Antarctic macroalgae could be a potential source of new compounds with promising application in biomedicine and suitability for synthetizing new materials, including metallic nanoparticles
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