Dihydromyricetin extraction and purification process

A dihydromyricetin extraction and purification process, comprising the following steps:

• step 1:
• weighing a raw material, adding an extraction solvent in an amount 5 times that of the raw material to perform reflux extraction, after performing three times of extraction and filtering of extraction solutions, combining filtrates from the three times of extraction, concentrating the filtrate to an extract, and recovering acetone;
• step 2:
• adding water to the extract in proportion and resting for crystallization for 24 hours;
• step 3:
• skimming off black oily substance floating on the surface, performing suction filtration to obtain light-green sediment underneath, and drying the sediment;
• step 4:
• heating and dissolving the crude product in pure water, and after thorough dissolution, adding 5%-10% activated carbon for decolorization and impurity removing;
• step 5:
• performing suction filtration, and cooling the mother solution and resting for crystallization;
• step 6:
• after the mother solution being cooled, performing suction filtration to obtain crystal, and drying the crystal so as to obtain white powder of dihydromyricetin;
• and
• step 7:
• detecting a content with HPLC.