US-12617764-B2 - Dihydromyricetin extraction and purification process

US12617764B2US 12617764 B2US12617764 B2US 12617764B2US-12617764-B2

Abstract

The present invention relates to the field of dihydromyricetin extraction and purification, and in particular to a dihydromyricetin extraction and purification process. Technical problem: the dihydromyricetin extraction and purification process aims to resolve the technical problems of increased cost of subsequent impurity removing and safety risks in high-temperature centrifugation in the prior art. Technical solution: a dihydromyricetin extraction and purification process: step 1: weighing a raw material, adding an extraction solvent in an amount 5 times that of the raw material to perform reflux extraction, concentrating the filtrate to an extract, and recovering acetone; step 2: resting for crystallization for 24 hours; step 3: performing suction filtration to obtain light-green sediment underneath, and dry the sediment; step 4: adding 5%-10% activated carbon for decolorization and impurity removing; step 5: performing suction filtration; step 6: drying to obtain white powder of dihydromyricetin; and step 7: detecting a content with HPLC.

Inventors

Xinxin Lu
Likang Chen
Yukang Zhang

Assignees

Dr Kang International Limited

Dates

Publication Date: 20260505
Application Date: 20240202

Claims (9)

1 . 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.
2 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the raw material is dry leaves of Ampelopsis grossedentata , produced in Zhangjiajie, Hunan Province, China, with an amount of 0.1 kg to 10 kg.
3 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the extraction solvent is acetone.
4 . The dihydromyricetin extraction and purification process according to claim 1 , wherein a temperature for the reflux extraction in step 1 is 60° C. and an extraction time is 50 minutes.
5 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the water in step 2 has a pH of 6±0.1 at room temperature.
6 . The dihydromyricetin extraction and purification process according to claim 1 , wherein a volume ratio of the extract to the water in step 2 is 1:7.
7 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the pure water in step 4 has a pH of less than 7.
8 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the amount of the pure water used in step 4 is 18-20 times that of the crude product.
9 . The dihydromyricetin extraction and purification process according to claim 1 , wherein the mother solution in step 6 is cooled to room temperature or below 15° C.

Description

TECHNICAL FIELD The present invention relates to the field of dihydromyricetin extraction and purification, and in particular to a dihydromyricetin extraction and purification process. BACKGROUND Dihydromyricetin is a special flavonoid compound having a variety of unique effects such as scavenging free radicals, an antioxidant effect, an antithrombotic effect, an anti-tumor effect, and an anti-inflammatory effect as well as the functions such as relieving alcoholism, preventing alcoholic liver disease and fatty liver disease, inhibiting deterioration of liver cells, and reducing the incidence of liver cancer, and it is a good choice for protecting liver and sobering up. There are many dihydromyricetin extraction and purification methods according to literature, for example, a hot water extraction method, an ultrasonic-assisted extraction method, and a microwave extraction method, etc. However, these methods have problems of poor subsequent decolorization and high costs for mass production with ultrasonic wave. As the domestic and foreign manufacturers keep the processes of optimization of dihydromyricetin extraction strictly confidential, there are just a few patents that have been granted. A method for separating and purifying myricetin and dihydromyricetin from Ampelopsis grossedentata is disclosed in the Chinese patent (CN201610621955.8) filed by Hunan Nutramax Inc. on Jul. 29, 2016. The scope of protection for the claims of the method comprises the following steps: step 1: preparation: weighing, selecting and crushing Ampelopsis grossedentata and then sieving it with a 35-45 mesh sieve; step 2: extraction: adding 75%-85% alcohol at a weight 18-22 times that of the Ampelopsis grossedentata, adding a 5% sodium bicarbonate solution to adjust the pH value to 7.0-8.0, soaking for 6-10 hours, and then performing reflux extraction at a temperature of 35-45° C. for 3-5 hours; step 3: secondary extraction: adding 75%-85% alcohol at a weight 8-12 times that of the Ampelopsis grossedentata, and performing reflux extraction at a temperature of 35-45° C. for 3-5 hours; step 4: filtration: combining liquid from the two times of extraction and performing filtration to obtain a filtrate; step 5: alcohol recovery: recovering alcohol from the filtrate until the alcohol concentration is 15% or below, and then performing vacuum concentration to obtain an extract having a specific gravity of 1.0-1.5; step 6: water sedimentation: mixing the concentrated extract thoroughly with hot water of 90-98° C. at a weight 18-22 times that of the concentrated extract and performing ultrasonic oscillation for 2.5-35 hours, performing high-speed centrifugation at a temperature of 80-90° C., and collecting a supernatant; step 7: centrifugation: refrigerating the supernatant obtained in step 6 overnight, performing high-speed centrifugation the next day, collecting a sediment, and performing vacuum drying to obtain the initial yellow-green extract powder; step 8: separation and purification: separating and purifying the initial extract obtained in step 7 to obtain myricetin and dihydromyricetin pure products having a high purity of 98% or above. A process for extracting myricetin and dihydromyricetin is disclosed in the Chinese patent (CN105037310A) filed by Liuzhou Lvxiang Biotechnology Co., Ltd. on Jun. 5, 2015. The scope of protection for the claims of the method comprises the following steps: with Ampelopsis grossedentata as a raw material, the specific steps are as follows: 1) triple extractions: adding a fresh raw material of 500 g of leaves of Ampelopsis grossedentata into 3 L of 60% ethanol, stirring, and cold soaking for 2 hours, performing filtration with 100-mesh filter cloth, and then collecting a filtrate; adding 3 L of 60% ethanol to the filter residue, stirring, and cold soaking for 2 hours, performing filtration with 100-mesh filter cloth, and then collecting a filtrate; and adding 1 L of 60% ethanol and 150 g of vitamin C to the filter residue after the second extraction, stirring, and cold soaking for 1 hour, performing filtration with 100-mesh filter cloth, and collecting a filtrate; 2) clarification: combining the three filtrates collected in step 1), adding 1 ml of a clarifying agent, stirring well and resting, and then performing filtration on the clarified liquid with a suction filtration tank in which 3 g of diatomaceous earth is spread as a filter aid; 3) decolorization and filtration: adding 10 g of activated carbon and 2 g of vitamin C, heating up to 60 Celsius degrees and maintaining the temperature, stirring for 20 minutes, and then performing liquid drainage for filtration; 4) crude crystal formation: cooling the filtrate for crystallization, and performing crystal suction filtration to obtain 180 g of dihydromyricetin crude crystal having a content of 80%; 5) refining: heating 540 ml of 30% ethanol to 62 Celsius degrees, adding vitamin C in an amount 1.5 times that of the crude crystal first, then adding the c