Maximizing the Antioxidant Capacity of Padina pavonica by Choosing the Right Drying and Extraction Methods

Marine algae are becoming an interesting source of biologically active compounds with a promising application as nutraceuticals, functional food ingredients, and therapeutic agents. The effect of drying (freeze-drying, oven-drying, and shade-drying) and extraction methods (shaking at room temperature, shaking in an incubator at 60 degrees C, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE)) on the total phenolics content (TPC), total flavonoids content (TFC), and total tannins content (TTC), as well as antioxidant capacity of the water/ethanol extracts from Padina pavonica were investigated. The TPC, TFC, and TTC values of P. pavonica were in the range from 0.44 +/- 0.03 to 4.32 +/- 0.15 gallic acid equivalents in mg/g (mg GAE/g) dry algae, from 0.31 +/- 0.01 to 2.87 +/- 0.01 mg QE/g dry algae, and from 0.32 +/- 0.02 to 10.41 +/- 0.62 mg CE/g dry algae, respectively. The highest TPC was found in the freeze-dried sample in 50% ethanol, extracted by MAE (200 W, 60 degrees C, and 5 min). In all cases, freeze-dried samples extracted with ethanol (both 50% and 70%) had the higher antioxidant activity, while MAE as a green option reduces the extraction time without the loss of antioxidant activity in P. pavonica.

Automated summary

Marine algae are a promising source of biologically active compounds for nutraceuticals, functional food ingredients, and therapeutic agents. Different drying and extraction methods were studied for their effects on the phenolics, flavonoids, tannins content, and antioxidant capacity of water/ethanol extracts from Padina pavonica. The highest phenolics content was found in the freeze-dried sample extracted with MAE.