Viral pneumonia has been a serious threat to global health, especially now we have dramatic challenges such as the
COVID-19 pandemic. Approximately six million cases of community-acquired
pneumonia occur every year, and over 20% of which need hospital admission. Influenza virus, respiratory virus, and coronavirus are the noteworthy causative agents to be investigated based on recent clinical research. Currently,
anaphylactic reaction and
inflammation induced by
antiviral immunity can be incriminated as causative factors for clinicopathological symptoms of
viral pneumonia. In this article, we illustrate the structure and related
infection mechanisms of these viruses and the current status of
antiviral therapies. Owing to a set of
antiviral regiments with unsatisfactory clinical effects resulting from side effects, genetic mutation, and growing incidence of resistance, much attention has been paid on medicinal plants as a natural source of
antiviral agents. Previous research mainly referred to
herbal medicines and
plant extracts with curative effects on
viral infection models of influenza virus, respiratory virus, and coronavirus. This review summarizes the results of
antiviral activities of various medicinal plants and their isolated substances, exclusively focusing on natural products for the treatment of the three types of pathogens that elicit
pneumonia. Furthermore, we have introduced several useful screening tools to develop
antiviral lead compounds.