Research progress of tannins in traditional Chinese medicines in recent ten years

Abstract

In this paper, the newly isolated tannins were sorted after a review of the literature concerning tannins in recent 10 years, and their research progress was summarized in terms of extraction, isolation, pharmacological activity and metabolism. Hydrolysable tannins and condensed tannins are the main structural types. Modern research shows that tannins have many pharmacological effects, such as bacteriostasis, antioxidation, antitumor, antivirus and blood glucose reduction, and have broad development prospects. They are usually extracted by water, ethanol and acetone and isolated and purified by macroporous resin and gel column chromatography. The packings commonly adopted for the column chromatography mainly included Sephadex LH-20, Diaion HP-20, MCI-gel CHP-20 and Toyopearl HW-40. Modern analytical techniques such as nuclear magnetic resonance spectroscopy(NMR), fast atom bombardment mass spectrometry(FAB-MS) and circular dichroism(CD) are generally used for the structural identification of tannins. Howe-ver, their isolation, purification and structural identification are still challenging. It is necessary to use a variety of high-throughput screening methods to explore their pharmacological activities and to explore the material basis responsible for their functions through experiments in vivo.