Phenolic Profile of Dunaliella tertiolecta growing under iron stress

Abstract

The phenolic profile of exudates and extracts of the green alga Dunaliella tertiolecta harvested in natural seawater (control) and in natural seawater enriched with Fe(III) (50 µg L−1) was investigated. The use of reversed phase high performance liquid chromatography (RP-HPLC) allowed the identification of 14 phenolic constituents. Determining how polyphenol concentrations change in response to high iron levels will demonstrate the role of polyphenols in microalgae and might be useful to help explain the dy- namics of this important compound in seawater. The polyphenolic profile showed relevant modifications when D. teritolecta was exposed to iron. The role of several polyphenols is related to the availability of Fe(II) in solution, encouraging its persistence. The in vitro antioxidant activity determined by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay revealed that the extract of cells from the control exhibited higher radical scavenging activity (14±0.5%) than the synthetic compound butylated hydroxytoluene (BHT) (5±0.1%), commonly used in the food industry as preservative. The presence of polyphenols within the cell confirms that D. teritolecta is a rich source of antioxidants to be used in the fields of preventive medicine and food preservatives.