Filicinic Acid Based Meroterpenoids with Anti-Epstein–Barr Virus Activities from Hypericum japonicum

Seven filicinic acid–based meroterpenoids (1–7), possessing 6/6/11, 6/6/7/5, or 6/6/10 ring systems, were isolated from Hypericum japonicum. All of them have novel skeletons with the incorporation of sesquiterpenoid moieties to an acylated filicinic acid. Compounds 2a and 4 exhibited significant efficacy on anti-Epstein–Barr virus, with EC₅₀ values of 0.57 and 0.49 μM, respectively. Furthermore, compounds 2a and 4 were well accommodated to the binding pocket of 2GV9 predicted by the molecular docking.