Establishment of Simple Cell-based Screening Assay and the Identification of Potent Antiviral Activity of a Plant Extract against HSV-1

Backgrounds: Drug screening is a time-consuming and costly process confronted with low productivity and challenges in using animals, which limits the discovery of new drugs. The cell-based assay allows the minimization of using the animal models and can provide more relevant in vivo biological information than biochemical assay. Objective: We aimed to establish a simple cell-based screening assay for the discovery of lead extract against HSV-1. Materials and Methods: Assay setting up was performed by optimization of the cell, incubation time, virus titer, and determination of Z value. Results: We have successfully established reproducible methods, by setting up assay plate including determination: 1) Vero cells as a model for HSV-1 infection, 2) Incubation for 5 days as sufficient time for CPE endpoint at monolayer cells, 3) 100 TCID₅₀/well HSV-1 as infection titer which caused high percentage of cell detachment, 4) determination of Z value of 100 TCID₅₀/well infection > 0.5. In addition, the established system was tested using ACV as the most common anti-HSV drug. Furthermore, we demonstrated the current system to screen extracts from Acacia nilotica, Uncaria gambir and Aspalathus linearis against HSV-1. It was observed that the alkaline extract of Uncaria gambir exhibited the highest SI (12.5) compared to other extracts. Conclusion: We demonstrated current cell-based screening system was reproducible and able to identify lead extracts against HSV-1 infection.