Antiviral phlorotannin from Eisenia bicyclis against human papilloma virus in vitro

The edible brown alga Eisenia bicyclis belongs to the family Lessoniaceae and is distributed along the coastal area of Korea and Japan [1, 2]. It has been used as an industrial source of alginic acid, and an edible alga [2]. Previous studies on E. bicyclis have afforded several phlorotannins, and have investigated various biological activities. Genital human papillomavirus (HPV) infection is the most common sexually transmitted infection, and virtually most of cervical cancers are attributable to HPVs infection. In the course of a search for anti-HPV compound from natural products, we have found that the EtOH extract of E. bicyclis has anti-viral activity against HPV16PVs and HPV18PVs. The EtOH extract was consecutively partitioned with CH₂Cl₂, EtOAc and n-BuOH, and the EtOAc fraction, which showed comparatively higher anti-viral activity than the other fractions, was subjected to column chromatographic separation. Five phlorotannins were isolated from the EtOAc fraction, and their structures were identified as eckol, dieckol, 8,8'-bieckol, 6,6'-bieckol, and phlorofucofuroeckol-A. Anti-viral activity for isolated compounds was evaluated using bio-luminescence (SEAP) assay on HPV16PVs and HPV18PVs infected 293TT cells. All compounds exhibited reduction of HPV16PVs and HPV18PVs at concentration 50 µg/mL.

References:

[1] Boo SM, Ko YD. Marine Plants from Korea. Seoul: Junghaeng-Sa; 2012; 119

[2] Yohei F, Reiji T, Hideo M, Yutaka T, Mitsuyoshi U, Toshiyuki S. Evaluation for antioxidative properties of phlorotannins isolated from the brown alga Eisenia bicyclis, by the H-ORAC method. Food Nutr Sci, 2013; 4: 78 – 82