In recent years seaweeds have increasingly attracted interest in the search for new drugs and have been shown to be a primary source of bioactive natural compounds and biomaterials. In the present investigation, the biochemical composition of the red seaweed Gracilaria gracilis, collected seasonally in the Lesina Lagoon (Southern Adriatic Sea, Lesina, Italy), was assayed by means of advanced analytical techniques, such as gas-chromatography coupled with mass spectrometry and spectrophotometric tests. In particular, analysis of lipids, fatty acids, sterols, proteins, phycobiliproteins and carbohydrates as well as phenolic content, antioxidant and radical scavenging activity were performed. In winter extracts of G. gracilis, a high content of R-phycoerythrin together with other valuable products such as arachidonic acid (PUFA ω-6), proteins and carbohydrates was observed. High antioxidant and radical scavenging activities were also detected in summer extracts of the seaweed together with a high content of total phenols. In conclusion, this study points out the possibility of using Gracilaria gracilis as a multi products source for biotechnological, nutraceutical and pharmaceutical applications even although more investigations are required for separating, purifying and characterizing these bioactive compounds.

ZnO nanocrystals of different shapes and sizes have been synthesized using an innovative, simple and efficient dry reactive milling methodology using Zn(NO₃)₂ and various polysaccharides as sacrificial templates. Optimum results were achieved using extracted agar from the red seaweed Gracilaria gracilis. Upon template removal after calcination at 600 °C, the protocol gave rise to a range of porous metal oxide nanomaterials of different shapes and nanoparticle sizes which were found to have excellent photocatalytic properties in aqueous phenol degradation as compared to commercial P25 Evonik titania.