Abstract
Background: Rhinoviruses and influenza viruses cause the majority of acute respiratory infections (ARIs). Symptoms of ARIs are commonly treated with over-the-counter products like ambroxol, bromhexine, and N-acetylcysteine, as well as thyme and pelargonium extracts. Because the antiviral activity of these over-the-counter products has not been studied in a systematic way, the current study aimed to compare their antiviral effect against two rhinovirus and two influenza virus strains in an in vitro setting. Methods: The cytotoxicity of ambroxol, bromhexine, and N-acetylcysteine, as well as of thyme and pelargonium extracts was analyzed in Madin-Darby canine kidney (MDCK) and HeLa cells. The antiviral effect of these over-the-counter products was compared by analyzing the dose-dependent inhibition (i) of rhinovirus A2- and B14-induced cytopathic effect in HeLa cells and (ii) of influenza virus A/Hong Kong/68 (subtype H3N2)- and A/Jena/8178/09 (subtype H1N1, pandemic)-induced cytopathic effect in MDCK cells at non-cytotoxic concentrations. Results: The results revealed a good compatibility (no or only marginal cytotoxicity in MDCK and HeLa cells) of the agents that were tested. No anti-rhinoviral activity was detected at non-cytotoxic concentrations in this in vitro study setting. Ambroxol, bromhexine, and N-acetylcysteine inhibited the influenza virus-induced cytopathic effect in MDCK cells no or less than 50%. In contrast, a dose-dependent anti-influenza virus activity of thyme and pelargonium extracts was demonstrated. Conclusions: The results of our comparative in vitro study indicate differences in the antiviral efficacy of ambroxol, bromhexine, and N-acetylcysteine, as well as of thyme and pelargonium extracts and suggest that the inhibition of influenza virus replication by thyme and pelargonium extracts may contribute to the beneficial effects of these plant extracts on ARI symptoms.
Cytotoxic Activity of Apixaban on HeLa Cells: An In vitro Study
