(−)-Epigallocatechin gallate inhibits hepatitis C virus (HCV) viral protein NS5B

In this study, we elucidated a small molecule inhibitor on viral protein NS5B identified through a high-throughput screening strategy using optical nanoparticle-based RNA oligonucleotide. We have previously shown that quantum dots (QDs)–RNA oligonucleotide can specifically recognize the HCV viral proteins. We have also demonstrated that conjugated QDs–RNA oligonucleotide can specifically and sensitively interact with designed biochips [1,2]. Among the flavonoids examined, (−)-epigallocatechin gallate (EGCG) demonstrated a remarkable inhibition activity on HCV viral protein, NS5B. (−)-Epigallocatechin gallate, at 0.005 μg mL−1 or more, concentration-dependently attenuated the binding affinity on a designed biochip as evidenced by QDs–RNA oligonucleotide. At a concentration of 0.1 μg mL−1, (−)-epigallocatechin gallate showed a 50% inhibition activity on QDs–RNA oligonucleotide biochip assay. We screened a small molecule inhibitor on the viral protein, NS5B, identified through a high-throughput screening strategy using on-chip optical nanoparticle-based RNA oligonucleotide on chip. In this designed strategy, the convenient and efficient screening and development of an on-chip viral protein inhibitor using a QDs–RNA oligonucleotide assay is achievable with high sensitivity and simplicity. In addition, this platform is expected to be applicable toward the inhibitor screening of other types of diseases.