Article

Journal of Applied Phycology

, Volume 20, Issue 5, pp 705-711

Antioxidant activities of phlorotannins isolated from Japanese Laminariaceae

  • Toshiyuki ShibataAffiliated withLaboratory of Quality in Marine Products, Department of Life Sciences, Graduate School of Bioresources, Mie University Email author 
  • , Kanji IshimaruAffiliated withDepartment of Applied Biological Sciences, Faculty of Agriculture, Saga University
  • , Shigeo KawaguchiAffiliated withDepartment of Animal and Marine Bioresource Sciences, Faculty of Agriculture, Kyushu University
  • , Hiromichi YoshikawaAffiliated withDepartment of Life, Environment and Materials Sciences, Faculty of Engineering, Fukuoka Institute of Technology
  • , Yoichiro HamaAffiliated withDepartment of Applied Biochemistry and Food Sciences, Faculty of Agriculture, Saga University

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Abstract

The antioxidant activities of brown algal phlorotannins were evaluated using the inhibition of phospholipid peroxidation in the liposome system, and by determining radical scavenging activities against the superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH). Oligomers of phloroglucinol (1,3,5-trihydroxybenzene), eckol (a trimer), phlorofucofuroeckol A (a pentamer), dieckol and 8,8′-bieckol (hexamers), isolated from the Laminarian brown algae Eisenia bicyclis, Ecklonia cava and Ecklonia kurome, showed potent inhibition of phospholipid peroxidation at 1 μM in the liposome system. The phlorotannins had significant radical scavenging activities against the superoxide anion (50% effective concentration values: 6.5–8.4 μM) and DPPH (50% effective concentration values: 12–26 μM), and were more effective compared to ascorbic acid and α-tocopherol. For the purpose of using phlorotannins as functional food ingredients, the antioxidant activity of a complex of crude phlorotannins and soybean protein was examined. The complex had a pronounced DPPH-radical scavenging activity. These results suggest that phlorotannins are potent anti-inflammatory substances, and that the Laminariaceous brown algae, which are abundant in phlorotannins, may be useful as a new functional foodstuff or supplement with anti-inflammatory activity.

Keywords

Brown algae DPPH-radical Liposome Phlorotannin–soy bean protein complex Phaeophyta Polyphenols Superoxide anion radical