Thearubigins: a comprehensive study from formation mechanism to biological activity and application prospects

Thearubigins (TRs) are a class of water-soluble, acidic phenolic compounds that are generated through oxidative polymerization reactions during the fermentation of black tea. As the predominant constituents in black tea, TRs significantly influence its unique color, texture, and potential health benefits. However, compared to polyphenols in black tea with lower molecular weights, research on TRs is more limited due to their diverse and complex nature. This paper reviews the current status of research on TRs production, the progress in isolation and preparation methods, and discusses the pharmacological effects of TRs, including their roles in antioxidant, anti-aging, anti-mutagenic, anti-cancer, and anti-tumor activities, as well as their anti-inflammatory properties and potential in preventing obesity. It also explores the prospects of TRs' application in the fields of food coloring, chemical, and healthcare industries. Despite their potential, the isolation and purification of TRs remain challenging due to their structural complexity and heterogeneity. Future studies should integrate various scientific techniques to further explore the bioactivity and mechanisms of action of TRs. The aim of this study is to provide a comprehensive overview that will serve as a reference for future research and application of high molecular weight polyphenols, such as TRs.