Characterizing Eckol as a Therapeutic Aid: A Systematic Review

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

Given the importance of severe acute respiratory syndrome coronavirus 3C-like proteinase (SARS-CoV 3CL pro ) in viral replication, a biological assessment was completed on the phlorotannins isolated from E. cava. In this study, the E. cava phlorotannins were shown to inhibit SARS-CoV3CL pro competitively in cell-free systems. Phloroglucinol, triphlorethol A, eckol, dioxinodehydroeckol, 2-phloroeckol, 7-phloroeckol, fucodiphloroethol G, dieckol, and phlorofucofuroeckol-A were isolated from the ethanol extract of E. cava. Except for phloroglucinol, all the other phlorotannins displayed inhibition on 3CL pro hydrolysis in a dose-dependent manner. The IC 50 values ranged from 2.7 to 164.7 µM where eckol (IC 50 8.8 µM) and dieckol (IC 50 2.7 µM) exhibited potent inhibitory effect on SARS-CoV 3CL pro cell-free cleavage with eckol structure being essential and crucial for good inhibition of SARS-CoV 3CL pro [68] .