Evaluation of the antioxidant and neuroprotective activity of the seaweed Durvillaea antarctica (cochayuyo) extracts using pressurized liquids

This study presents a novel vision of the brown seaweed Durvillaea antarctica aka ‘cochayuyo’ as an important food commonly consumed in Chile. ´Cochayuyo´ is a rich source of antioxidant and neuroprotective activity compounds demonstrated by evaluating the bioactivity associated with conventional and pressurized liquid extracts. Variables such as extraction yield, DPPH antioxidant assay, TEAC, and acetylcholinesterase (AChE) inhibitory capacity were studied employing Central Composite Design (CCD) based on a response surface methodology (RSM) and Pareto charts. Firstly, solvent polarity was evaluated by conventional extraction for the best antioxidant activity and they were employed in the experimental design (water/ethanol variations). Then, factors such as temperature (40–180 °C) and solvents (water/ethanol in 0, 50 to 100%) were selected resulting in CCD (12 total runs). In general, pressurized liquid extraction (PLE) improved the extraction yield and antioxidant activities compared to conventional extraction (twofold more using water). Moreover, PLE results showed that a higher yield (63.28%), was obtained with 50:50% water/ethanol at 180 °C. However, DPPH antioxidant assay was improved at the same temperature under 100% ethanol (EC 50 equal to 0.16 mg mL −1 ). For the neuroprotective activity, D. antarctica extracts were enriched under low-intermediate temperature (40–110 °C) and 100% water (IC 50 equal to 148.62 μg mL −1 ). After multiple response optimization, the best conditions to obtain antioxidant and neuroprotective extracts with high yield were 180 ºC and a ratio of 71:29 water:ethanol as extraction solvent. The results indicated that D. antarctica could be considered a functional food with significant antioxidant benefits and neuroprotective effects on human health.