Curcumin is an APE1 redox inhibitor and exhibits an antiviral activity against KSHV replication and pathogenesis

Curcumin, a polyphenol, is the main bioactive compound in dietary spice turmeric curcuma longa. It possesses anti-inflammatory, anti-oxidant and anti-neoplastic properties and shows potentials in treating or preventing particular diseases such as oxidative and inflammatory conditions, metabolic syndrome, arthritis, anxiety, hyperlipidemia and cancers. The diverse range and potential health beneficial effects has generated enthusiasm leading to intensive investigation into the phytochemical. However, a concern has been also raised if curcumin has a promiscuous bioassay profile and is a Pan-Assay INterference compound (PAINS). Here we present evidence indicating that curcumin is not a PAINS, but an inhibitor to APE1 redox function that affects many genes and pathways. This discovery explains the wide range of effects of curcumin on diverse human diseases and predicts a potential application in treatment of viral infection and virus-associated cancer. As a proof-of-concept, we demonstrated that curcumin is able to efficiently block Kaposi's sarcoma-associated herpesvirus replication and inhibit the pathogenic processes of angiogenesis and cell invasion.