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Phlorotannins as radical scavengers from the extract of Sargassum ringgoldianum
Masaaki Nakai1, Norihiko Kageyama, Koichi Nakahara
1Suntory Research Center, Suntory, Ltd., Wakayamadai 1-1-1, Shimamoto-cho, Mishima-gun, Osaka, 618-8503, Japan. Masaaki_Nakai@suntory.co.jp
Abstract:
To screen algal phlorotannins with antioxidative activities, 50% ethanol extracts of 25 Japanese marine algae were evaluated. Scavenging activity against superoxide anion radicals was frequently found with a high content of total phenolic compounds. Among these, the extract from the brown seaweed, Sargassum ringgoldianum, showed the strongest scavenging activity. The active fraction contained a mixture of high molecular weight polyphenols, phlorotannins that were found to be polymerized bifuhalol, as analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The scavenging activity of the fraction against superoxide anion radicals was estimated to be 1.0 microg/ml (IC(50)), which were approximately five times stronger than that of catechin.
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