EBV DNA polymerase inhibition of tannins from Eugenia uniflora

Nasopharyngeal carcinoma (NPC) is one of the high population malignant tumors among Chinese in southern China and southeast Asia. Epstein-Barr virus (EBV) is a human B lymphotropic herpes virus which is known to be closely associated with NPC. EBV DNA polymerase is a key enzyme during EBV replication and is measured by its radioactivity. The addition of phorbol 12-myristate 13-acetate to Raji cell cultures led to a large increase in EBV DNA polymerase, which was purified by sequential DEAE-cellulose, phosphocellulose and DNA-cellulose column chromatography. Four tannins were isolated from the active fractions of Eugenia uniflora L., which were tested for the inhibition of EBV DNA polymerase. The results showed the 50% inhibitory concentration (IC₅₀) values of gallocatechin, oenothein B, eugeniflorins D₁ and D₂ were 26.5 62.3, 3.0 and 3.5 μM, respectively. Furthermore, when compared with the positive control (phosphonoacetic acid), an inhibitor of EBV replication, the IC₅₀ value was 16.4 μM. In view of the results, eugeniflorins D₁ and D₂ are the potency principles in the inhibition of EBV DNA polymerase from E. uniflora. Copyright (C) 2000 Published by Elsevier Science Ireland Ltd.