Lichens and spore-derived cultured mycobionts of Teloschistes chrysophthalmus and Ramalina celastri were studied chemically, and results indicated that they produced, respectively, parietin and usnic acid as major secondary metabolites, which were purified and identified. Identification of the compounds was performed by high performance liquid chromatography and structural elucidation by nuclear magnetic resonance ( ¹ H) and electron impact mass spectrometry. Usnic acid exhibited antiviral activity whereas parietin had a virucidal effect against the arenaviruses Junín and Tacaribe

Bioassay guided purification of the ethyl acetate extract of leaves of Melia azedarach led to the isolation of the limonoid 1-cinnamoyl-3,11-dihydroxymeliacarpin, which showed IC₅₀ values of 6 μᴍ and 20 μᴍ for vesicular stomatitis (VSV) and herpes simplex (HSV-1) viruses, respectively. Its structure was established by spectroscopic methods.