Characterizing Eckol as a Therapeutic Aid: A Systematic Review

Manandhar, Bandana; Paudel, Pradeep; Seong, Su Hui; Jung, Hyun Ah; Choi, Jae Sue

Similarly, histamine release assay was performed on human basophilic leukemia (KU812) and RBL2H3 to assess the anti-allergic activities of phloroglucinol derivatives, fucodiphloroethol G, eckol, and phlorofucofuroeckol-A isolated from E. cava. Their inhibitory potential on the release of histamine was evaluated by their ability to inhibit immunoglobulin E (IgE) and anti-IgE antibodies stimulated degranulation of KU812 cells. Fucodiphloroethol G, eckol, and phlorofucofuroeckol-A displayed 23.97%, 44.26%, and 34.54% of relative histamine release, respectively, at the highest concentration (100 µM). In both the KU812 and RBL2H3 cells, calcium ionophore A23187 mediated the inhibitory effect of the phlorotannins. The histamine release percentages in RBL-2H3 cells treated with fucodiphloroethol G, eckol, and phlorofucofuroeckol-A were 27.73%, 50.63%, and 34.18%, and the degranulation percentages of RBL-2H3 cells were 18.02%, 31.67%, and 20.80%, respectively. Eckol, having fewer hydroxyl functional groups than the other two compounds, showed less inhibition on the histamine release in both cell lines, particularly compared with fucodiphloroethol G comprising of 11 hydroxyl functional groups. The molecular structure and amount of phenol groups could be the important factors for fucodiphloroethol G and phlorofucofuroeckol-A for showing strong activity than eckol. Also there was a potent inhibition of the binding activity between IgE and its receptor (30.58% and 34.23%) when treated with the highest concentration of fucodiphloroethol G and phlorofucofuroeckol-A, whereas eckol displayed less inhibiton (47.60%) in the flow cytometric analysis [73] . Thus, eckol from E. cava showed moderate antiallergic activity as compared to other compounds due to the structural differences amid the compounds in terms of the number of hydroxyl groups and the linkages among the phenol units, leading to different inhibitory activity.