Background
COVID-19 triggered an unprecedented global public health emergency with catastrophic economic consequences. Upon infection, innate immune system detects viral patterns through pattern recognition receptors, triggering an antiviral defense response.
Objective
Bioactive compounds, such as quercetin, curcumin, and beta-glucan, regulate innate immunity to combat viral infections. These compounds are well-known for their powerful anti-inflammatory and immune-regulating properties, which hold great potential for applications in food science, pharmaceuticals, and healthcare.
Results
Scientists suggest that bioactive compounds from fruits, vegetables and whole grains are associated with innate immunity, especially in gut-liver-brain axis regulation getting more and more important. Evidence suggests several promising bioactive compounds play an important role in innate immunity, including quercetin, curcumin and β-glucan. Quercetin regulates the innate immune primarily by inhibiting oxidative stress, reducing inflammatory factors, and modulating the NF-κB pathway. Curcumin exerts immunomodulatory effects by inhibiting innate immune signaling molecules and maintaining the integrity of the blood-brain barrier. β-glucan regulates the innate immune response by stimulating the TLR4 receptor, activating macrophages, generating chemokines, and maintaining the balance between pro- and anti-inflammatory responses.
Conclusion
The gut-liver-brain axis is increasingly important for the regulation of innate immunity. Bioactive compounds regulate innate immunity through the gut-liver-brain axis via several mechanisms: (1) enhancing macrophage phagocytosis and preventing the entry of harmful microbials into the body; (2) inhibiting the translocation of NF-κB from the cytoplasm to the nucleus in the gut through metabolites such as short-chain fatty acids; and (3) modulating the intestinal microbiota to maintain the integrity of the blood-brain barrier.