Figure 2.

Proanthocyanidins structure, properties and application. Proanthocyanidins, a type of polyphenolic compound, are widespread in fruits and plants, such as grapes, cranberry, black currant, pomegranate, cocoa and medlar. Proanthocyanidins possess antioxidation, immunomodulation and anti-inflammation effects and are used in numerous disorders (such as OS-associated diseases inflammatory disorders, cardiovascular dysfunction and diabetes). Mechanism of action involves inhibiting OS (decreasing ROS and MDA and increasing SOD, GSH and catalase), reducing inflammatory responses (inhibiting IL-17, IL-6, IL-21, IL-22 and TNF-α) and balancing immunity (reducing Th2, Th17 and B cells and increasing Treg cells) via the suppression of the TLR4/MyD88/NF-κB signaling pathway. OS, oxidative stress; ROS, reactive oxygen species; MDA, malondialdehyde; TLR4, toll-like receptor 4; MyD88, myeloid differentiation factor 88; NF-κB, nuclear factor κ-B; Th, T helper; IL, interleukin; TNF-α, tumor necrosis factor-α; SOD, superoxide dismutase; GSH, glutathione; Ɵ, suppression; ↑↑, upregulation; ↓↓, downregulation.