Could natural products modulate early inflammatory responses, preventing acute respiratory distress syndrome in COVID-19-confirmed patients?

Background: The ARDS (Acute Respiratory Distress Syndrome) is a severe respiratory syndrome that was recently associated as the main death cause in the COVID-19 pandemic outbreak. Hence, in order to prevent ARDS, the pulmonary function maintenance has been the target of several pharmacological approaches. However, there is a lack of reports regarding the use of effective pharmaceutical active natural products (PANPs) for early treatment and prevention of COVID-19-related ARDS. Therefore, the aim of this work was to conduct a systematic review regarding the PANPs that could be further studied as alternatives to prevent ARDS. Consequently, this work can pave the way to spread the use of PANPs on the prevention of ARDS in COVID-19-confirmed or -suspected patients.

Methods: The search strategy included scientific studies published in English from 2015 to 2020 that promoted the elucidation of anti-inflammatory pathways targeting ARDS by in vitro and/or in vivo experiments using PANPs. Then, 74 studies regarding PANPs, able to maintain or improve the pulmonary function, were reported.

Conclusions: The PANPs may present different pulmonary anti-inflammatory pathways, wherein (i) reduction/attenuation of pro-inflammatory cytokines, (ii) increase of the anti-inflammatory mediators' levels, (iii) pulmonary edema inhibition and (iv) attenuation of lung injury were the most observed biological effects of such products in in vitro experiments or in clinical studies. Finally, this work highlighted the PANPs with promising potential to be used on respiratory syndromes, allowing their possible use as alternative treatment at the prevention of ARDS in COVID-19-infected or -suspected patients.