Algicidal effect of phlorotannins from the brown alga Ecklonia kurome on red tide microalgae

A Comparison of the Antioxidant Properties and Total Phenolic Content in a Diatom, Chaetoceros sp. and a Green Microalga, Nannochloropsis sp.

“…was found to have the highest total phenolic content. Surprisingly, the methanol extract from the same species showed negative results for phenolic content, but it showed high antioxidant capacities in other assays, indicating that the high antioxidant capacity is not related to the phenolic compounds, consistent with the study by Nagayama, Shibata, Fujimoto, Honjo & Nakamura (2003). All of the solvent extracts from Nannochloropsis sp.…”

“…Many phenolic compounds have been reported as antioxidants, such as pheophytin from green microalgae (Nishibori & Namiki, 1988) and phlorotannins from brown microalgae (Nagayama, Shibata, Fujimoto, Honjo & Nakamura, 2003), but they might not be major contributors to the antioxidant capacities of microalgae (Li, Cheng, Wong, Fan, Chen, & Jiang, 2007). In this study, the hexane extract of Chaetoceros sp.…”

Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitory Phlorotannins from Edible Brown Algae,Ecklonia stoloniferaandEisenia bicyclis

“…17) Phlorotannins are secondary metabolites polymerizing phloroglucinol (1,3,5-trihydroxybenzene) through an ether, phenyl, or 1,4-dibenzodioxin linkage. These polyphenolic compounds are responsible for a variety of bioactivities, including anti-diabetic complications, 17,18) and antitumorial, 19) hepatoprotective, 20) anti-plasmin inhibiting, 21) algicidal, 22) tyrosinase inhibiting, 23) antiinflammatory, 24,25) nitrite-scavenging, 26) anti-skin aging, 27,28) antioxidative, [29][30][31] anti-cholinesterase, 32,33) antiAlzheimer, 34) anti-hyperlipidemic, 35) anti-diabetic, [36][37][38][39] anti-allergic, 40) and angiotensin converting enzyme-I inhibitory activities. 41) As part of our continuous search for antidiabetic agents from natural sources, we investigated the MeOH extract and solvent-soluble fractions of the two selected brown algae, E. stolonifera and E. bicyclis, together with six isolated phlorotannins against -glucosidase and PTP1B.…”

Mode of action of an antialgal agent produced by a marine gammaproteobacterium against Chattonella marina

“…In fact, PG-L-1 showed potent algicidal activity against these dinoflagellates (Nakashima et al 2006). In addition, it has been reported that phlorotannins, which are antioxidants, isolated from the brown alga Eisenia bicyclis showed algicidal effect on dinoflagellates such as C. polykrikoides and G. mikimotoi (Nakamura et al 1996, Nagayama et al 2003. These findings suggest a possibility that scavenging or elimination of ROS lead to the inhibition of the growth of certain algal species, especially ROS-producing phytoplankton.…”