New Method for Extracting and Purifying Dihydromyricetin from Ampelopsis grossedentata

Dihydromyricetin (DMY) is a kind of flavone. It has a variety of physiological effects, and its content in Ampelopsis grossedentata is as high as 35%. There are two shortcomings in the traditional batch extraction process commonly used in a laboratory: long extraction time and low extraction rate. In this study, a new chelating extraction method was proposed, that is, Zn²⁺ was introduced into the extraction and purification process to chelate with DMY, and the yield and purity were taken as evaluation indices for a comparative study with the traditional batch extraction method. In addition, ¹H NMR, single-crystal X-ray diffraction, IR, and UV were used to analyze the product structure; thermogravimetry and differential thermal analysis was utilized to examine the thermal stability of DMY. The results were shown as follows. Compared with the batch extraction method, the chelation extraction method could effectively avoid the oxidation of DMY by air during the extraction and purification process, and the yield of the DMY also increased. Furthermore, this method was time-saving. Through investigating the extraction process and characterizing the structure and thermal stability of DMY, the chelating extraction method could be considered to provide a reference for commercial applications of DMY.