Inhibitory activity of brown algal phlorotannins against hyaluronidase

Abstract

The inhibitory effect of brown algal phlorotannins on hyaluronidase was evaluated by an in vitro assay. Crude phlorotannins from the brown algae Eisenia bicyclis and Ecklonia kurome had a stronger inhibitory effect than well-known inhibitors such as catechins and sodium cromoglycate. IC 50 values of the following six phlorotannins: phloroglucinol, an unknown tetramer, eckol (a trimer), phlorofucofuroeckol A (a pentamer), dieckol and 8,8¢bieckol (hexamers), were 280, 650, >800, 140, 120 and 40 lM, respectively. The IC 50 of catechin, epigallocatechin gallate and sodium cromoglycate was 620, 190 and 270 lM, respectively. 8,8¢-Bieckol, the strongest HAase inhibitor in this study, acted as a competitive inhibitor with an inhibition constant (K i ) of 35 lM. Acetylation of the phlorotannins markedly decreased their inhibitory potency.

Radical Scavenging and Hyaluronidase Inhibitory Activities of Phlorotannins from the Edible Brown Alga Eisenia arborea

“…Although the strong effect of PFF-A corresponded to the results of Shibata et al (2002), this paper is the first to report the inhibitory effects of 6,8'-bieckol and PFF-B on hyaluronidase activity. Our previous study has shown that the inhibitory effect of the eckol on degranulation from rat basophile leukemia (RBL)-2H3 cells was the weakest compared to those of the other five phlorotannins (Sugiura et al, 2007).…”

“…In this study, the inhibitory effect of the eckol on the hyaluronidase activity was also the weakest compared to those of the other five tested phlorotannins. When the phlorotannins from E. bicyclis were investigated for their hyaluronidase inhibitory activities, the activity of eckol was the weakest of all the tested phlorotannins (Shibata et al, 2002). As the molecular size of eckol is the smallest (372) of all the tested phlorotannins, the molecular size may be an important factor governing the inhibitory effects of the phlorotannins on the hyaluronidase activity and degranulation from RBL cells.…”

“…It is also known that oxidative stress is involved in various inflammatory and allergic reactions (Bowler and Crapo, 2002;Matsuzawa et al, 2005), and hyaluronidase is closely related to such reactions (Kakegawa et al, 1985;Sakamoto et al, 1980). The anti-oxidative and anti-hyaluronidase effects of several phlorotannins from Eisenia bicyclis have already been reported (Nakamura et al, 1996;Shibata et al, 2002). Therefore, we investigated whether the six phlorotannins from E. arborea exhibit effects similar to the phlorotannins from E. bicyclis by examining its DPPH radical scavenging and hyaluronidase inhibitory activities.…”

Seasonal variation of polyphenolics inAscophyllum nodosum(Phaeophyceae)

“…The pharmacological activities observed include inhibition of a number of enzymes such as hyaluronidase, phospholipase A, lipoxygenase, cyclooxygenase-1, glycosidases, tyrosinase, HIV-1 reverse transcriptase and HIV-1 protease (e.g. Shibata et al, 2002a;Shibata et al, 2002b;Shibata et al, 2003;Ahn et al;, Kang et al, 2004b, antioxidative effects (e.g. Nakamura et al, 1996;Chkhikvishvili & Ramazanov, 2000;Jimenez-Escrig et al, 2001;Kang et al, 2004a) and antibacterial activity (Nagayama et al, 2002;Sandsdalen et al, 2003).…”

Isolation of a New Anti-Allergic Phlorotannin, Phlorofucofuroeckol-B, from an Edible Brown Alga,Eisenia arborea

“…3) Phlorotannins have been reported to have certain biological activities, such as antioxidation, 4) bactericide, 5) anti-cancer, 6) anti-diabetic complications, 7,8) and chemoprevention against several vascular diseases. 9,10) Although some anti-inflammatory activities of phlorotannins have also been reported, 11,12) their inhibitory effect on histamine release from the stimulated cultured cells is still unknown.…”