Echinacea purpurea aerial parts contain multiple antiviral compounds

Abstract Stems, leaves, and flowers of Echinacea purpurea. (L.) Moench (Heliantheae: Asteraceae) were fractionated by various solvents and the fractions evaluated for antiviral activity in relation to chemical composition and distribution within the plant. All of the aqueous fractions contained potent activity against herpes simplex virus and influenza virus. However, although some of this activity could be attributed to polysaccharide and cichoric acid components, their individual contributions could not account for the total antiviral activity; other potent antivirals must be present. In addition, the ethanol- and ethyl acetate-soluble fractions from leaves and stem contained an uncharacterized but potent antiviral photosensitizer, which was absent from the flower extract. None of the fractions, however, contained anti-rhinovirus activity. Thus, part of the alleged benefits of Echinacea purpurea. extracts can be attributed to the presence of anti-influenza and anti-HSV compounds, and some of these activities are likely to be present in various commercial tinctures, teas, capsules, and tablets.