Keywords: Clinacanthus nutans; herpes simplex virus type 1 (HSV-1); cytotoxicity; plaque assay

Abstract

Clinacanthus nutans, also known as snake grass, is a local medicinal plant that displays antimicrobial, antiviral, and anticancer immunomodulatory activities. Whole dried plants were macerated with methanol for crude extract preparation. The focus of this study was to assess the cytotoxicity and antiviral activities of the C. nutans crude extract. Cytotoxicity screening against Vero cells using MTT assay showed that the CC50 value of the crude extract of C. nutans was 1.625 mg/mL. Plaque reduction assays were carried out to evaluate the antiviral activity of the extract against herpes simplex virus type 1 (HSV-1). These included post-treatment, pre-treatment, and virucidal assays. The selective indices (SI = CC50 / EC50) of the extract in post-treatment, pre-treatment, and virucidal assays were 11, 6, and 3, respectively. Our results indicate that C. nutans has a promising potential to be explored as a source of potent antiviral products.