Natural Products: A Potential New Hope to Defeat Post-acute Sequelae of COVID-19

The COVID-19 pandemic was the most significant public healthcare crisis worldwide. It was estimated that 80% of infected patients with COVID-19 have not fully recovered and developed one or more long-term symptoms, referred to as post-acute sequelae of COVID-19 (PASC). Seeking a treatment strategy for PASC has become a concerning topic since the sequelae can cause irreversible multiple organ damage and can severely compromise quality of life. It is indicated that PASC may be closely related to lung injury-induced hypoxia, excessive immune response, cytokine storm, gut bacteria imbalance, and endothelial dysfunction. Also, more and more research has indicated that angiotensin-converting enzyme 2 (ACE2) receptor, transient receptor potential ankyrin 1 and vanillin 1 (TRPA1/V1), and nuclear factor erythroid 2-related factor 2 (Nrf2) can be considered as the targets to treat PASC. There is currently still no proven medication for PASC due to its complexity. Many clinical practices and studies have shown that natural products have great potential in preventing and treating PASC. Therefore, we intended to provide a comprehensive review of the current literature on PASC and the role of natural ingredients in PASC management. Meanwhile, this review provided meaningful insight for further study of natural ingredients to improve PASC and its clinical application.