Screening of medicinal plants from El Salvador for anti-viral activity against Herpes simplex 1.

Herpes simplex virus 1 is one of the most prevalent pathogens worldwide. Resistant strains to current anti-viral treatment have been reported, requiring the search for novel anti-virals. Using a qPCR method to assess anti-herpetic activity from natural products, we analyzed 72 plant extracts from El Salvador and identified eighteen methanolic extracts with anti-viral activity of ≥ 75%. Anti-herpetic activity has not been previously reported in fourteen of the plants ( Euphorbia lancifolia , Piper tuberculatum , Cordia alliodora , Tecoma stans , Taraxacum officinale , Hamelia patens , Witheringia solanacea , Emilia fosbergii , Gnaphalium viscosum , Citrus aurantium , Ambrosia peruviana , Carica papaya , Solanum hazenii and Melothria pendula ). Four extracts were from species with previously reported anti-herpetic activity ( Plantago major , Psidium guajava , Sida acuta and Bursera simaruba ). These extracts effective anti-viral concentrations (EC 50 ) were between 203 and 6.31 µg/mL, while the selectivity indexes (SI) were between 55.91 and 2.57. Euphorbia lancifolia showed the most effective anti-viral activity (EC 50 = 6.31 µg/mL, SI = 51.82).