Biomass and antioxidant activity of Polysiphonia abscissa: effects of drying and solvent extraction

PEREZ, M.C.; CROCE, M. E; CROCI, C.A.; PARODI, E. R.

Halifax

Congreso; 4th Congress of the International Society for Applied Phycology; 2011

International Society for Applied Phycology, National Research Council Canada

Natural sources of antioxidants became of great importance in recent years. In this context, natural populations of Polysiphonia abscissa from North-atlantic Patagonia should be noticed. Individuals were harvest in intertidal pools and their winter biomass (june 2010) was estimated as wet (WW) and dry weight (DW). Another 30 individuals were collected to determine DW/WW ratio. Morphometric measurments were obtained and their life cycle stage was determined. For antioxidant analysis, macroalgae were lyophilized or dried at 60°C. Methanolic (ME) and water extracts (WE) were prepared under an ultrasound bath (40°C, 2hs). Antioxidant activity (AA) was assessed by the reducing power (PR) and DPPH radical methods. Total phenolics were quatified through Folin-Denis. Average pool biomass was 2795.98 g.m-2 WW and 588.68 g.m-2 DW. The DW/WW regresion equation was y=0.458x-0.129 (p<<0.01). Average plant length and diameter were 13.14cm and 4.14cm respectively and 73% of the individuals were tetrasporophytes. AA of ME and WE were analyzed in concentrations between 0 and 60 mg of dried macroalgae/ml solvent. PR of every extract showed a linear increase with concentration as well as the DPPH assay. For lyophilized samples, the AA of ME was significantly higher than WE. Drying at 60°C caused a highly significant decrease of the AA from ME, as well as a decrease in total phenolic compounds. The AA of P. abscissa and mainly its high biomass suggests that these populations constitute a source of antioxidants. Lyophilization and methanol should be noticed as methods to improve antioxidants extraction from this species.