Polygonum cuspidatum, as a commonly used traditional Chinese medicine, has antibacterial, anti-oxidant, anti-viral and anti-cancer activities.
Reynoutria japonica, synonyms Fallopia japonica and Polygonum cuspidatum, is a species of herbaceous perennial plant of the knotweed and buckwheat family Polygonaceae.It is commonly known as Asian knotweed or Japanese knotweed. It is native to East Asia in Japan, China and Korea. In North America and Europe, the species has successfully established itself in numerous habitats, and is classified as a pest and invasive species in several countries.
The main active ingredients in Polygonum cuspidatum include resveratrol and emodin.
These active ingredients have the effects of reducing blood viscosity, inhibiting platelet coagulation and vasodilation, and keeping the blood flowing. They can be used to prevent the occurrence of cancer and control the development of cancer. They are natural products with development potential and are expected to become a new type with multiple functions. drug.
Extraction of effective ingredients from Polygonum cuspidatum
Reports on the extraction of active ingredients in Polygonum cuspidatum mainly focus on organic solvent reflux extraction and supercritical carbon dioxide extraction, but these extracted crude products still contain a lot of impurities, so subsequent purification and purification are still needed.
Since the crude extract of Polygonum cuspidatum has complex components and the content of active ingredients is still low, it is usually necessary to further concentrate and separate and purify the crude extract.
Chromatography is a commonly used method of separation and purification. It is often used in the stage of new drug development. However, because general laboratories only use batch chromatography to purify the target, the product is seriously diluted, solvent consumption is large, and adsorbent The efficiency is therefore reduced, so the operating cost is high.
If the chromatography technology can be given the function of continuous operation, its efficiency can be effectively improved, the operation cost can be reduced, and the time course for the development of new plant drugs can be effectively shortened.
Stimulate moving bed, SMB
Simulated moving bed is currently an effective continuous chromatography method, and the effectiveness of SMB in the purification of natural products has been reported.
For example, Wang Jianjian and others used corn silk extract as a raw material to purify corn silk flavonoids using SMB, achieving fine separation and large-scale.
SMB is applied to the separation of capsaicin from capsaicin, and completely separates the most important and difficult-to-separate capsaicin and dihydrocapsaicin in capsicum oil to obtain high-purity capsaicin.
At present, reports on the separation and purification of active ingredients in Polygonum cuspidatum by SMB are only for resveratrol, and this method uses methanol as the elution solvent, and sample pretreatment is also complicated.
This study proposes a method for purification and separation of resveratrol and emodin in Polygonum cuspidatum by using simulated moving bed technology. It also evaluates and compares the purification methods of simulated moving bed technology that uses supercritical carbon dioxide instead of traditional liquid washing liquid. result. This research provides a low-temperature, step-saving, and environmentally friendly production process for the manufacture of resveratrol and emodin.
Raw materials and analytical methods
Polygonum cuspidatum raw materials were purchased from a Chinese pharmacy in Taiwan. Resveratrol standard product (purity>98%, Shaanxi Hongyuan Biotechnology Company), emodin standard product (purity 89.7%, ChromaDex), emodin methyl ether (purity>98%) , Tauto Biotech CO., LTD.).
In this study, HITACHI liquid chromatography equipment was used, and the analysis was performed by gradient elution chromatography on a Thermo C18 column at room temperature.
The mobile phase flow rate is 1 mL/min, and the injection volume is 20L. In gradient elution mode, mobile phase A is pure acetonitrile, B is 0.1% phosphoric acid aqueous solution, and the detection wavelength is 305 nm. The elution program is set as follows: 0 min: 15%A; 15 min: 40%A; 25 min: 50%A; 30 min: 60%A; 31 min: 15%A; 40 min:
15%A. Due to the long time of gradient elution, this research further develops an isogradient analysis method to shorten the time required for analysis. The mobile phase used is acetonitrile: 0.1% phosphoric acid aqueous solution = 80:20 (V/V), and the detection wavelength is 285nm.
The purpose of isogradient analysis is to screen an appropriate stationary phase and to adjust the operating conditions for SMB purification and separation of resveratrol and emodin; the purpose of gradient analysis is to quantitatively analyze the content of the extracted product and improve the resolution of the purified product .
In this study, a total of two simulated moving bed experiments with different detergents were carried out:
(1) The crude extract of Polygonum cuspidatum extracted by supercritical carbon dioxide is used as the SMB feed to separate emodin, resveratrol, and emodin;
(2) Using the commercially available Polygonum cuspidatum crude extract as the feedstock of SF-SMB, emodin and resveratrol were separated.
This article aims to compare the advantages and disadvantages of using supercritical simulated moving bed (SF-SMB) and simulated moving bed (SMB) to separate resveratrol and emodin in Polygonum cuspidatum, mainly focusing on the impact of the two simulated moving beds on product purity and recovery. Investigate.
SF-SMB uses Merck LiChroprep® Si 60 (40~63 um) as the stationary phase, and ethanol as the co-solvent for supercritical carbon dioxide; SMB uses Merck 113900 LiChroprep RP-18 as the stationary phase and ethanol aqueous solution as the Mobile phase.
The results show that when the commercially available crude extract of resveratrol is used as the raw material, SF-SMB can obtain pure resveratrol at the extraction end under the operating conditions of 19.3 MPa, 40°C, and an ethanol content of 18 wt% , Its purity and recovery rate are respectively 99% and 96% or more, and the raffinate end can obtain pure emodin, and its purity and recovery rate are respectively 73% and 96% or more.
When the ethanol/water ratio of 95/5 is used as the mobile phase, and the crude extract obtained by supercritical carbon dioxide extraction of Polygonum cuspidatum is used as the raw material, SMB can obtain resveratrol and large-scale extracts at the extraction end and the raffinate end, respectively. Flavin, its purity and recovery rate are above 92%.
The comparison results show that the purity and recovery rate of SF-SMB are higher than the traditional solvent-based simulated moving bed, but the productivity is still higher with traditional SMB. If solvent recovery is further considered, SF-SMB has the advantage of convenient solvent recovery and is a purification technology worthy of continued efforts.