Algae. 2012; 27(3): 205-213.
Thermostability of a marine polyphenolic antioxidant dieckol, derived from the brown seaweed Ecklonia cava
Min-Cheol Kang1, Eun-A Kim1, Sung-Myung Kang1, W. A. J. P. Wijesinghe1, Xiudong Yang1, Nalae Kang1 and You-Jin Jeon1,*
1Department of Marine Life Sciences, Jeju National University, Jeju 690-756, Korea
The thermostability of antioxidant activity of dieckol, a phlorotannin isolated from brown seaweed Ecklonia cava was investigated. The thermostable antioxidant properties of dieckol were evaluated at 30, 60, and 90°C for 7 days using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities, and comparing its performance to that of ascorbic acid. The intracellular reactive oxygen species (ROS) scavenging activity and apoptotic body formation were investigated using DCF-DA assay and nuclear staining with Hoechst 33342, propidium iodide and flow cytometry. Dieckol treated at different temperatures during 7 days showed stable scavenging activities on towards DPPH and hydroxyl radicals. In addition, dieckol showed a stable protective effect against H2O2-induced apoptotic body formation in Vero cells. On the other hand, the radical scavenging activities and intracellular ROS scavenging activities of ascorbic acid, used as a positive control, were significantly decreased at 60°C and 90°C from on the 4th day and 3rd days, respectively. In conclusion, the results indicated that food grade antioxidant extracts containing dieckol derived from E. cava remain a stable during the temperatures encountered during the processing of food and cosmetics.
Keywords : antioxidant; brown seaweed; dieckol; Ecklonia cava; phlorotannin; thermostable