Anti- bovine viral diarrhea virus activity of cucurbitacins as new potential antiviral agents

Cucurbitacins are a group of tetracyclic triterpenoids found in plants of the family Cucurbitaceae. Cucurbitacins have a wide range of biological activities including anti-cancer, anti-inflammatory, and anti-viral activity. Bovine viral diarrhea virus (BVDV) is the prototype of Pestivirus genus of the Flavivridae family. BVDV is considered to be a surrogate for hepatitis C virus (HCV) in identifications and development of anti-HCV drugs. In this study, six cucurbitacins (B, D, E, E glucoside, Iso B, and Iso D) were isolated from Cucurbita texana (Cucurbitaceae), and characterized by spectroscopic methods (NMR, MS). The antiviral affect of cucurbitacin compounds against BVDV (NADL strain) was determined using colorimetric lactate dehydrogenase (LDH) assay. Four compounds (B, D, E, and E- glucoside) showed anti BVDV activity with a 50% effective concentration (EC₅₀) ranging between 0.025 and 2µM. A study to explore the mechanism of action using real time reverse transcription -PCR and anti-HCV activity of these compounds will be presented. This is the first known report of anti BVDV activity of cucurbitacin compounds.