Filicinic Acid Based Meroterpenoids with Anti-Epstein–Barr Virus Activities from <i>Hypericum japonicum</i>

Seven filicinic acid–based meroterpenoids (<b>1</b>–<b>7</b>), possessing 6/6/11, 6/6/7/5, or 6/6/10 ring systems, were isolated from <i>Hypericum japonicum</i>. All of them have novel skeletons with the incorporation of sesquiterpenoid moieties to an acylated filicinic acid. Compounds <b>2a</b> and <b>4</b> exhibited significant efficacy on anti-Epstein–Barr virus, with EC<sub>50</sub> values of 0.57 and 0.49 μM, respectively. Furthermore, compounds <b>2a</b> and <b>4</b> were well accommodated to the binding pocket of 2GV9 predicted by the molecular docking.