Biotechnological Applications for the Sustainable Use of Marine By-products: In Vitro Antioxidant and Pro-apoptotic Effects of Astaxanthin Extracted with Supercritical CO2 from Parapeneus longirostris

In this study, the carotenoid astaxanthin was obtained by supercritical fluid extraction (SFE) from shrimp by-products (SBP). Its bioactive properties were evaluated in vitro in human normal and cancerous cells lines. The antioxidant activity of the extracted astaxanthin of the SFE fraction (ASTA) was tested in fibroblast cells (HS-68), by inducing oxidative stress and by evaluating the protective effect of the pre-treatment with different levels of ASTA against toxicity. The anti-proliferative activity was evaluated in hepatoma cells (HEP-G2), treated with increased concentrations of ASTA and measuring the effects on vitality and on some biomolecular markers related to oxidative stress, cell cycle, and apoptosis. It was found that pre-treating normal fibroblast cells with ASTA resulted in a marked increase in cell viability in a dose-dependent manner (P < 0.05) attesting its antioxidant power; in cancer cell line, increased concentrations of ASTA caused a time-dose-dependent decrease in the vitality, attesting its anti-proliferative activity (P < 0.05). The increased levels of the protein p-53 and the reduced levels of the proteins c-Jun and c-Fos at higher concentrations of ASTA, as well as, suggest the pro-apoptotic and anti-cancerous effects that this extract has on hepatocellular carcinomas, confirmed also by caspase-3 activation. These findings suggest biotechnological utilisation of marine by-products for nutraceutical and pharmaceutical applications avoiding the employment of organic solvents for extraction.