Abstract

Coptidis Rhizoma is derived from the dried rhizome of Ranun-culaceous plants and is a commonly used traditional Chinese medicine. Although Coptidis Rhizoma is commonly used for its many therapeutic effects, antiviral activity against respi-ratory syncytial virus (RSV) has not been reported in detail. In this study, we evaluated the antiviral activities of Coptidis Rhizoma extract (CRE) against RSV in human respiratory tract cell line (HEp2) and BALB/c mice. An effective dose of CRE significantly reduces the replication of RSV in HEp2 cells and reduces the RSV-induced cell death. This antiviral activity against RSV was through the induction of type I inter-feron-related signaling and the antiviral state in HEp2 cells. More importantly, oral administration of CRE exhibited prophylactic effects in BALB/c mice against RSV. In HPLC analysis, we found the presence of several compounds in the aqueous fraction and among them; we confirmed that pal-matine was related to the antiviral properties and immune- modulation effect. Taken together, an extract of Coptidis Rhi-zoma and its components play roles as immunomodulators and could be a potential source as promising natural antivirals that can confer protection to RSV. These outcomes should encourage further allied studies in other natural products.

• Keywords: coptidis rhizoma (CR); palmatine; respiratory syncytial virus (RSV); antiviral effect