Current Advances in Naturally Occurring Caffeoylquinic Acids: Structure, Bioactivity, and Synthesis

Caffeoylquinic acids (CQAs) are a broad class of secondary metabolites that have been found in edible and medicinal plants from various families. It has been 100 years since the discovery of chlorogenic acid in 1920. In recent years, a number of naturally derived CQAs have been isolated and structurally elucidated. Accumulated evidence demonstrate that CQAs have a wide range of biological activities, such as antioxidation, antibacterial, antiparasitic, neuroprotective, anti-inflammatory, anticancer, antiviral, and antidiabetic effects. Up to date, some meaningful progresses on the biosynthesis and total synthesis of CQAs have also been made. Therefore, it is necessary to comprehensively summarize the structure, biological activity, biosynthesis, and chemical synthesis of CQAs. This review provides extensive coverage of naturally occurring CQAs discovered from 1990 until 2020. Modern isolation techniques, chemical data (including structure, biosynthesis, and total synthesis), and bioactivity are summarized. This would be helpful for further research of CQAs as potential pharmaceutical agents.