Natural polyphenols and their nanoformulations: A new era in anti-inflammatory therapy

Natural polyphenols are promising candidates for the treatment of chronic inflammatory disorders because they possess several antioxidant and anti-inflammatory properties within the diverse class of phytochemicals. However, their low bioavailability, poor water solubility, limited stability and rapid metabolism hinder clinical application. To address these limitations, nanotechnology-based delivery systems such as solid lipid nanoparticles, nanosuspensions, liposomes and polymeric nanoparticles have been developed. These systems can improve the bioavailability, stability and targeted tissue distribution of polyphenols. Such nanoformulations may enhance the pharmacokinetic profile and anti-inflammatory potential of polyphenols via inhibition of pro-inflammatory cytokines and modulation of anti-inflammatory signalling pathways (including MAPK and NF-κB). Preclinical research indicates that nanoencapsulated polyphenols such as quercetin, catechins, resveratrol and curcumin are more efficacious in reducing inflammation and accelerating tissue healing than their free forms in vitro and in animal models. The combination of natural polyphenols with nanotechnology-based delivery technologies may provide a promising direction for anti-inflammatory therapy. This review article highlights the anti-inflammatory properties of natural polyphenols and explores how nanoformulation approaches can mitigate issues related to poor bioavailability, instability and rapid metabolism.