A green and simple method for enrichment of major diterpenoids from the buds of Wikstroemia chamaedaphne with macroporous resins and their activation of latent human immunodeficiency virus activity.

In this study, a green and efficient enrichment method for the four majors active diterpenoid components: pimelotide C, pimelotide A, simplexin, and 6α,7α-epoxy-5ß-hydroxy-12-deoxyphorbol-13-decanoate in the buds of Wikstroemia chamaedaphne was established using macroporous resin chromatography. The adsorption and desorption rates of seven macroporous resins were compared using static tests. The D101 macroporous resin exhibited the best performance. Static and dynamic adsorption tests were performed to determine the enrichment and purification of important bioactive diterpenoids in the buds of W. chamaedaphne. Diterpenoid extracts were obtained by using D101 macroporous resin from the crude extracts of W. chamaedaphne. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated that most of the diterpenoids were enriched in diterpenoid extracts. These results confirmed that diterpenoids in the buds of W. chamaedaphne could be enriched using macroporous resin technology, and the enriched diterpenoid extracts showed more efficient activation of the latent human immunodeficiency virus. This study provides a novel strategy for discovering efficient and low-toxicity latency-reversing agents and a potential basis for the comprehensive development and clinical application of the buds of W. chamaedaphne.

Treatment of phenolic wastewater in an anaerobic fluidized bed microbial fuel cell filled with graphene oxide-macroporous adsorption resin as multifunctional carrier.

A novel graphene oxide-modified resin (graphene oxide-macroporous adsorption resin) was prepared and used as a multifunctional carrier in an anaerobic fluidized bed microbial fuel cell (AFB-MFC) to treat phenolic wastewater (PW). The macroporous adsorption resin (MAR) was used as the carrier, graphene oxide was used as the modified material, the conductive modified resin was prepared by loading graphene oxide (GO) on the resin through chemical reduction. The modified resin particles were characterized by scanning electron microscopy (SEM), Raman spectroscopy (RS), specific surface area and pore structure analysis. Graphene oxide-macroporous adsorption resin special model was established using the Amorphous Cell module in Materials Studio (MS), and the formation mechanism of graphene oxide-macroporous adsorption resin was studied using mean square displacement (MSD) of the force module. Molecular dynamics simulation was used to study the motion law of molecular and atomic dynamics at the interface of graphene oxide-macroporous adsorption resin composites. The strong covalent bond between GO and MAR ensures the stability of GO/MAR. When the modified resin prepared in 3.0 mg/mL GO mixture was used in the AFB-MFC, the COD removal of wastewater was increased by 9.1% to 72.44%, the voltage was increased by 84.04% to 405.8 mV, and power density was increased by 765.44% to 242.67 mW/m2.

A new combined technology: Macroporous adsorption resin and high speed counter current chromatography for hydroxytyrosol separation from olive leaf enzymatic hydrolysate.

Due to three free hydroxyl groups, hydroxytyrosol (HT) presents strong bioactivity and has broad food and drug application prospects. However, there is no good separation and purification technology. In this study, separation and purification technology of HT from the ethyl acetate extraction of enzymatic hydrolysate from olive leaf (EEEH) was investigated with macroporous adsorption resin (MAR) and high-speed counter-current chromatography (HSCCC) and the separation factors were optimized. First, the adsorption properties of eight MARs (AB-8, S-8, D-101, X-5, XAD-1, XAD-5, NKA-Ⅱ, H-103) for HT enrichment were studied. The results showed that H-103 macroporous resin was adsorbent, sample concentration was 1.5 mg/mL, eluent was 30 % ethanol solution, sample loading rate was 3.0 BV/h, elution velocity was 2.0 BV/h, and HT purity of EEEH was increased from 10.23 % to 40.78 %. Then, solvent systems were examined according to partition coefficients of target component and petroleum ether: ethyl acetate: methanol: water (4:6:4:6, v/v) system was chosen. The critical experimental parameters of HSCCC were optimized as following: revolution speed was 1200 rpm and flow rate was 3 mL/min. The HT purity of macroporous resin purified EEEH was increased from 40.78 % to 85.7 %. Therefore, MAR-HSCCC combined technology could be a very effective approach to separate and purify HT from EEEH.

Response surface methodology optimization of extraction and enrichment conditions of total triterpenoid saponins from Celosiae Semen and evaluation of its lipid-lowering activity.

The saponin-enriched extract from Celosiae Semen is a promising resource owing to its lipid-lowering activity. However, triterpenoid saponins are difficult to extract owing to their high molecular weight and strong water solubility. The aim of this paper was to explore an eco-friendly and effective technology of extraction and enrichment of total triterpenoid saponins to obtain high lipid-lowering fractions. Initially, Box-Behnken design experiments were employed to optimize the heat reflux extraction process on the basic of mono-factor experiments. Afterwards, the crude extract was further purified using D-101 resin, and the purification parameters were investigated based on adsorption/desorption experiments and biological activity assay. Under optimal conditions, the purity of the finally obtained total triterpenoid saponins was increased by 7.28-fold. The lipid-lowering activities of the six main triterpenoid saponins were evaluated in HepG2 cells induced by palmitic acid. The results of Oil Red O staining showed that the compounds all exhibited potential lipid-lowering activity. The structure-activity relationship analysis suggested that the oligosaccharide chain at C-28 played an essential role in their lipid-lowering activity and the substituent group at C-23 site also showed important effects. The optimal extraction and purification methods may facilitate the utilization of Celosiae Semen for the industrial production as a functional food and drug.

Optimized Separation of Carthamin from Safflower by Macroporous Adsorption Resins and Its Protective Effects on PC12 Cells Injured by OGD/R via Nrf2 Signaling Pathway.

The growing demand for safe natural products has reignited people's interest in natural food pigments. Here, we proposed the use of macroporous adsorption resins (MARs) to separate and purify carthamin from safflower. The optimal parameters for carthamin purification with HPD400 MAR were determined as follows: a mass ratio of crude carthamin in sample solution to wet resin of 0.3, a crude carthamin solution concentration of 0.125 g·mL-1, a pH of 6.00, a sample volume flow rate of 0.5 mL·min-1, an ethanol volume fraction of 58%, an elution volume of 4 BV, and an elution volume flow rate of 1.0 mL·min-1. Under the above purification conditions, the recovery rate of carthamin was above 96%. Carthamin dramatically improved the survival rate of PC12 cells damaged by oxygen-glucose deprivation/reoxygenation and protected them from oxidative stress by inhibiting the generation of reactive oxygen species and increasing the total antioxidant capacity and glutathione (GSH) levels. Carthamin promoted extracellularly regulated protein kinase phosphorylation into the nucleus, permitting Nrf2 nuclear translocation and upregulating the gene expression of the rate-limiting enzymes glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase regulatory subunit of GSH synthesis to obliterate free radicals and exert antioxidant effects. This study revealed the purification method of carthamin and its antioxidant protective effects, providing important insights into the application of carthamin in functional foods.

An integrated process by ultrasonic enhancement in the deep eutectic solvents system for extraction and separation of chlorogenic acid from Eucommia ulmoides leaves.

This study established an integrated process for the extraction and enrichment of chlorogenic acid(CGA)from Eucommia ulmoides leaves in a deep eutectic solvent system via ultrasonic wave-enhanced adsorption and desorption practices utilizing macroporous resins. Although deep eutectic solvents (DESs) have the advantages of chemical stability, good dissolving capacity, and nonvolatilization, routine solvent recovery operations are not suitable for subsequent separation in this solvent system. Based on the above characteristics, this study integrated the extraction and enrichment processes, in which DESs extracts directly loaded onto the macroporous adsorption resin, avoiding the loss of target components in solvent recovery and redissolution processes. The screening results of solvents and resin types further showed that choline chloride-malic acid (1:1) was the optimal DES, and the NKA-II resin had high adsorption and elution performance for CGA. The viscosities of the DESs were much higher than those of water and conventional organic solvents; thus, the mass transfer resistance was large, which could also affect the adsorption behaviour of the macroporous resin. The thermal and mechanical effects of ultrasound could effectively enhance the efficiency of the mass transfer, adsorption, and desorption in the DES systems. When compared to no sonication treatment, the CGA adsorption at various ultrasonic powers (120-600 W) was examined. At optimal ethanol concentration (60%), the effect of the ultrasonic treatment on the recovery of the DESs (water eluting process) and the desorption capability of CGA were confirmed. The use of three volumes of water elution could recover the DESs without loss of CGA. The adsorption process significantly differed depending on the ultrasonic settings, and the absorption balance time and experimental adsorption capacity at equilibrium were enhanced. Additionally, the adsorption procedure of the NKA-II macroporous resin for CGA under ultrasonic treatment could be clarified by the pseudo second order kinetic equation and the Freundlich isotherm model. Thermodynamic and dynamic parameters indicated that physical adsorption was the main process of the entire procedure, and it was a spontaneous, exothermic, and entropy-reducing physical adsorption process. This study potentially indicates that the use of ultrasonication, as a high-efficiency, environmentally friendly method, can enhance the features of the macroporous resin to better purify target chemicals from a DES extract.

Extraction methods and compositions of polyphenols in Shanxi aged vinegar.

The extraction, purification, qualification, and quantification of polyphenols (PPs) in vinegar are challenging owing to the complex matrix of vinegar and the specific physicochemical and structural properties of PPs. This study aimed to develop a simple, efficient, low-cost method for enriching and purifying vinegar PPs. The enrichment and purification effects of five solid phase extraction (SPE) columns and five macroporous adsorption resins (MARs) for PPs were compared. The results show that SPE columns were more effective in purifying vinegar PPs than MARs. Among them, the Strata-XA column showed a higher recovery (78.469 ± 0.949%), yield (80.808 ± 2.146%), and purity (86.629 ± 0.978%) than other columns. In total, 48 PPs were identified and quantified using SPE and gas chromatography-mass spectrometry from the SPE column extracts; phenolic acids, such as 4-hydroxyphenyllactic acid, vanillic acid, 4-hydroxycinnamic acid, 4-hydroxybenzoic acid, protocatechuic acid, and 3-(4-Hydroxy-3-methoxyphenyl) propionic acid, occupy a major position in SAV. Furthermore, considering the potential applications of PPs, the concentrates were characterized based on their bioactive properties. They exhibited high total PP, flavonoid, and melanoidin contents and excellent anti-glycosylation and antioxidant activities. These results indicate that the established methodology is a high-efficiency, rapid-extraction, and environment-friendly method for separating and purifying PPs, with broad application prospects in the food, chemical, and cosmetic industries.

A combination of surface-initiated atom transfer radical polymerization and photo-initiated "thiol-ene" click chemistry: Fabrication of functionalized macroporous adsorption resins for enrichment of glycopeptides.

A hydrophilic adsorbent (Cys@poly(AMA)@MAR) was successfully prepared for the enrichment of N-glycopeptides via surface-initiated atom transfer radical polymerization (SI-ATRP) and photo-initiated "thiol-ene" reaction using monodisperse macroporous adsorbent resin (MAR) as adsorption matrix. Due to the presence of electron-deficient acrylic groups and electron-rich vinyl groups in allyl methacrylate (AMA), both of them can participate in free radical reaction. Therefore, the polymerization time of SI-ATRP was optimized. The resulting poly(AMA)@MAR was modified with l-cysteine (L-Cys) via photo-initiated "thiol-ene" reaction, and the amount of vinyl retained was determined by measuring the adsorption of Cu2+. The Cys@poly(AMA)@MAR pendant brushes with high density of amine and carboxyl groups could capture N-glycopeptides from IgG digest and human serum digest by hydrophilic interaction. The 22 N-glycopeptides were identified from IgG digest and the limit of detection reached 10 fmol. The 319 N-glycosylation sites and 583 N-glycopeptides were identified from 2 µL human serum digest and mapped to 147 glycoproteins. It demonstrates great potential and commercialization prospects for the enrichment of N-glycopeptides.

Sustainable recovery of melanoidins from thermal hydrolyzed sludge by macroporous resin and properties characterization.

Melanoidins, the dark-color recalcitrant Maillard reaction by-products in thermal hydrolyzed sludge (THS), cause significant adverse effects on wastewater treatment. This study aimed to develop an efficient adsorption method for recovering melanoidins from THS by macroporous resin. The adsorptive characteristics of six macroporous resins (XAD761, XAD8, XAD16HP, FPX66, HPD-600 and IRA958Cl) showed that XAD761, not yet reported for melanoidins extraction, was the most appropriate with the highest recovery ratio. The adsorption kinetics followed pseudo-second-order model, and the adsorption process was confirmed to be physical, spontaneous, and exothermic, without changing the structure of the adsorbed melanoidins. In the dynamic adsorption, the breakthrough point increased with a decreasing flow rate. After five consecutive regeneration cycles, XAD761 resin maintained stable adsorption efficiency and thus had a good potential for reuse. Furthermore, the physicochemical properties of the extracted THS melanoidins were compared with model melanoidins to lay the foundation for their management, in terms of morphology, molecular weight (MW), and spectrophotometric properties. These results demonstrate that XAD761 resin extraction is a promising sustainable method for practical application in the recovery of melanoidins from THS.

Monodisperse Ti4+-immobilized macroporous adsorbent resins with polymer brush for improved multi-phosphopeptides enrichment in milk.

Enrichment of phosphopeptides before mass spectrometry (MS) analysis is essential due to the limitations of low abundance and poor ionization efficiency in complex biological samples. Immobilized metal affinity chromatography (IMAC), especially titanium ion (Ti4+)-IMAC, has become a popular strategy for enrichment of phosphopeptides due to high selectivity and sensitivity. Conventional Ti4+-immobilized macroporous adsorption resin (MAR) fabricated by monolayer modification can preferentially capture mono-phosphopeptide over multi-phosphopeptides, which takes on more functions in the regulation of cell behaviors of organism. In this paper, a kind of monodisperse MAR microsphere with functional polymer brush (Ti4+-Brush@MAR) was prepared and modified via surface-initiated atom transfer radical polymerization (SI-ATRP). Compared with common Ti4+-MAR without polymer brush, Ti4+-Brush@MAR exhibited high enrichment specificity not only for mono-phosphopeptides but also for multi-phosphopeptides in ß-casein or milk digest samples. As a result, a total of 93 unique phosphopeptides mapped to 18 phosphoproteins were identified from 5 µL milk, and the limit of detection is 10 fmol. It is expected that Ti4+-Brush@MAR would be utilized to enrich both multi-phosphopeptides and mono-phosphopeptides in additional biological or food samples.

Optimized extraction of astaxanthin from shrimp shells treated by biological enzyme and its separation and purification using macroporous resin.

The best enzymatic protease treatment of shrimp shells was identified by comparing the enzymatic hydrolysis effects of many different types of biological enzymes using fresh Arctic sweet shrimp as raw materials. The optimal enzymolysis conditions were determined using neutral protease as the best enzymatic protease. Among multiple macroporous adsorption resins, XDA-8 macroporous adsorption resin was preferable due to its static adsorption rate and desorption rate. The yield of astaxanthin (134.20 µg/g) after treatment with neutral protease was 3.7 times higher than that of the control group (36.03 µg/g). The yield of astaxanthin was obviously improved after enzymolysis of the shrimp shells. The purity of the astaxanthin was up to 87.34%, approximately 6508 times higher than that of the raw material. The production cost of astaxanthin would be greatly reduced by use of XDA-8 resin to obtain high-purity astaxanthin. This technique offers a high value-added utilization of shrimp shells.

Facile preparation of bifunctional adsorbents for efficiently enriching N-glycopeptides and phosphopeptides.

In bottom-up strategy, specific enrichment of glycopeptides and phosphopeptides from complicated biological samples is a prerequisite for efficient identifying glycosylation and phosphorylation by mass spectrometry. Although there were a plethora of materials used as either hydrophilic interaction liquid chromatography (HILIC) or immobilized metal affinity chromatography (IMAC) adsorbents, even several bifunctional materials for simultaneous enrichment of glycopeptides and phosphopeptides, most of them are not easily commercialized as many other well-performing adsorbents due to the complicated preparation process. In our case, a one-step modification strategy was developed to prepare bifunctional adsorbents for HILIC and IMAC, employing O-phospho-l-serine as the modifier and poly(GMA-co-EDMA) microspheres, a kind of macroporous adsorption resin (MAR) with epoxy groups, as the matrix. The MARs were directly modified with O-phospho-l-serine under facile condition for HILIC strategy and further chelated with Ti4+ for IMAC strategy. A total of 522 unique N-glycopeptides and 442 unique N-glycosylation sites mapped to 275 N-glycoproteins was identified from HeLa cell proteins, showing excellent enrichment efficiency in HILIC. Additionally, 3141 unique phosphopeptides were unambiguously identified from 200 µg of digest of HeLa cell proteins, demonstrating great enrichment efficiency in IMAC. Moreover, these materials have been successfully applied in the analysis of multiple biological samples including human serum and milk, demonstrating their feasibility for real sample applications and potential business value.

Optimization of total polyphenol purification from purple tea by macroporous resin / 药学实践杂志

Objective To screen the macroporous adsorption resin suitable for the separation and purification of total polyphenols from purple tea and establish the purification process parameters to prepare high-purity total polyphenols from purple tea. Methods The static adsorption-elution test was used to screen macroporous adsorption resin for the purification of total polyphenols from purple tea. Based on the single factor test, the comprehensive score of adsorption rate was used as the index to investigate the effects of different factors on the purification process and identify the optimal parameters for the purification process. Those factors included sample concentration, the pH value of the sample solution, the ratio of column diameter to height, sample size, ethanol percentage in the eluent, eluent volume and elution flow rate. Results The best process parameters for purification of total polyphenols from purple tea by AB-8 macroporous adsorption resin were as following. The sample concentration was 375 μg/ml with flow rate 2 ml/min. The sample volume was 3 BV. The sample solution pH was 2. The ratio of colume diameter to height was 1∶6. The impurities were removed first by water 3 BV. 50% ethanol 4 BV was used for elution with flow rate 2 ml/min. Conclusion AB-8 macroporous resin was selected for the purification of polyphenols from purple tea under the optimized technological conditions. The mass fraction of total polyphenols increased from 40.2% to an average of 69.8%. The solid content decreased from 56.0 mg to 29.9 mg. The established purification process has good stability and feasibility. It can be used as a purification process for total polyphenols from purple tea.

Enhancing effect of macroporous adsorption resin on gamma-aminobutyric acid production by Enterococcus faecium in whole-cell biotransformation system.

Gamma-aminobutyric acid (GABA) biosynthesis depended to a great extent on the biotransformation characterization of glutamate decarboxylase (GAD) and process conditions. In this paper, the enhancing effect of D101 macroporous adsorption resin (MAR) on the GABA production was investigated based on the whole-cell biotransformation characterization of Enterococcus faecium and adsorption characteristics of D101 MAR. The results indicated that the optimal pH for reaction activity of whole-cell GAD and pure GAD was 4.4 and 5.0, respectively, and the pH range retained at least 50% of GAD activity was from 4.8 to 5.6 and 4.0-4.8, respectively. No substrate inhibition effect was observed on both pure GAD and whole-cell GAD, and the maximum activity could be obtained when the initial L-glutamic acid (L-Glu) concentration exceeded 57.6 mmol/L and 96.0 mmol/L, respectively. Besides, GABA could significantly inhibit the activity of whole-cell GAD rather than pure GAD. When the initial GABA concentration of the reaction solution remained 100 mmol/L, 33.51 ± 9.11% of the whole-cell GAD activity was inhibited. D101 MAR exhibited excellent properties in stabilizing the pH of the conversion reaction system, supplementing free L-Glu and removing excess GABA. Comparison of the biotransformation only in acetate buffer, the GABA production, with 50 g/100 mL of D101 MAR, was significantly increased by 138.71 ± 5.73%. D101 MAR with pre-adsorbed L-Glu could significantly enhance the production of GABA by gradual replenishment of free L-Glu, removing GABA and maintaining the pH of the reaction system, which would eventually make the GABA production more economical and eco-friendly.

Effects of macroporous adsorption resin on antibiotic resistance genes and the bacterial community during composting.

Swine manure is considered a reservoir for antibiotic resistance genes (ARGs), which may enter the soil and then the food chain to endanger human health. This study investigated the effects of adding 0%, 5%, and 15% (w/w) macroporous adsorption resin (MAR) on ARGs and the bacterial community during composting. The results showed that the addition of MAR reduced the abundances of ARGs (14.14-99.44%) and mobile genetic elements (MGEs) (47.83-99.48%) after swine manure composting. Significant positive correlations were detected between ARGs and MGEs, and thus the variations in MGEs may have led to the changes in ARGs. Redundancy analysis showed that MGEs had stronger effects on ARGs than environmental factors and the bacterial community. Network analysis suggested that ARGs and MGEs co-existed in common host bacteria. In conclusion, the results showed that adding 5% MAR can reduce the risk of ARG transmission.

Purification process of epimedin and icariin from Epimedii Folium by macroporous resin / 中草药

Objective: To investigate the best technological conditions for the purification of epimedin and icariin from Epimedii Folium by macroporous resin, and preliminarily characterize the purification fraction of the best technological conditions. Methods: Five kinds of macroporous resins were screened by static adsorption experiment with the content of epimedin A1, epimedin A, epimedin B, epimedin C and icariin as indexes. The best purification conditions were optimized by the concentration of upper column solution, the maximum sample volume, the upper column flow rate, the volume of water washing, the concentration of removing impurity ethanol and elution ethanol, the volume of removing impurity ethanol and elution ethanol, the column diameter-height ratio through dynamic adsorption experiment. Finally, UPLC-Q-TOF/MS, HPLC and ultraviolet spectrophotometry were used to characterize the purification fraction of the best technological conditions. Results: The best macroporous resin was AB-8, column diameter-height ratio was 1:7, 6 BV of upper column solution (crude drug 0.5 g/mL) was used for dynamic adsorption at a flow rate of 6 BV/h, 5 BV of water and 5 BV of 20% ethanol were used for impurity removal, and 6 BV of 50% ethanol was used for elution. The flow rate of impurity removal and elution was 6 BV/h. After purification, the total flavonoids content was 63.29%, the total content of epimedin A1, A, B, C and icariin was 40.48%, the content of epimedin A1, epimedin A, epimedin B, epimedin C and icariin was 1.63%, 2.52%, 16.36%, 5.51% and 14.46%, respectively. Conclusion: The purification process of epimedin and icariin from Epimedii Folium by AB-8 macroporous resin is stable, reasonable and feasible. The chemical characterization indicated that the purification fraction was mainly flavonoids, mainly consisting of epimedin and icariin. The optimized purification process can be used for the purification and enrichment of such ingredients.

Investigation of Adsorption Properties of Five Macroporous Resins for Total Flavonoids in Epimedii Folium / 中国实验方剂学杂志

Objective::To compare the adsorption characteristics of different macroporous adsorption resins for the total flavonoids in Epimedii Folium, clarify the adsorption mechanism, and screen the optimal resin for the purification of total flavonoids in Epimedii Folium. Method::Taking the adsorption and desorption capacities of the total flavonoids in Epimedii Folium and five representative flavonoids (epimedin A, epimendin B, epimendin C, icariin, baohuoside Ⅰ) as indexes, static adsorption and dynamic adsorption experiments were conducted to compare the adsorption characteristics of five macroporous including HPD100, HPD600, AB-8, X-5 and D101.The adsorption kinetics of the selected resin was studied by using the pseudo-first-order, pseudo-second-order kinetic models and intraparticle diffusion model, and the thermodynamic process was analyzed by using the Langmuir and Freundlich isothermal adsorption models, which explored the adsorption mechanism of resin from the perspective of physical chemistry. Result::HPD100 macroporous resin had a better adsorption and desorption properties than the others. The adsorption process of HPD100 macroporous resin for total flavonoids in Epimedii Folium and five representative flavonoids conformed to the pseudo-second-order kinetic model. The adsorption thermodynamic process of HPD100 resin for total flavonoids of Epimedii Folium conformed to the Freundlich model, and for the sum of five representative flavonoids conformed to the Langmuir model. The adsorption process of HPD100 resin for total flavonoids in Epimedii Folium was the exothermic process dominated by physical adsorption, and the optimal adsorption temperature was 25 ℃. Conclusion::HPD100 macroporous resin has large adsorption capacity, easy desorption and clear adsorption mechanism, it is suitable for isolation and purification of total flavonoids in Epimedii Folium.

Effective extraction with deep eutectic solvents and enrichment by macroporous adsorption resin of flavonoids from Carthamus tinctorius L.

In the present study, deep eutectic solvents (DESs) were prepared and firstly applied to extract flavonoids from Safflower using ultrasonic-assisted extraction (UAE), and DES2-UAE was selected as a green and efficient extraction method. The effects of extraction parameters on extraction efficiency (EE) of flavonoids were investigated by single-factor experiments and optimized using a Box-Behnken design (BBD). The optimal results were 56.37 mL/g liquid-solid ratio, 55.85 min extraction time, 41.44 °C extraction temperature and 188.55 W ultrasonic power, respectively. Under optimal extraction conditions, the highest EE of flavonoids (55.41 mg/g) was obtained. The verification experimental results were in good correlation with the predicted results. The adsorption and desorption experiments of flavonoids on five types of macroporous resins (NKA-2, AB-8, HPD-100, D-101 and S-8) were carried out, NKA-2 and S-8 showed higher adsorption/desorption capacities, successively followed by AB-8, D-101 and HPD-100. The adsorption behaviors were better explained by Langmuir isotherm model according to correlation coefficient on the basis of static adsorption test at different temperature. In conclusion, the developed DES2-UAE combined with macroporous resin enrichment can be an alternative method for the green and efficient extraction of bioactive flavonoids from plant materials.

Study on purification of total flavonoids from Litchi Semen by macroporous resin / 中草药

Objective To screen the macroporous adsorption resin suitable for the separation and purification of total flavonoids from Litchi Semen, and the purification process parameters were established to prepare the total flavonoids of Litchi Semen in accordance with the requirements of effective parts of Chinese materia medica, which laid the foundation for the development of the total flavonoids of Litchi Semen into five new Chinese medicines. Methods The macroporous adsorption resin for purifying the total flavonoids of Litchi Semen by static adsorption-elution test was used. Based on the single factor test, the comprehensive score of adsorption rate was used as the index to investigate the volume fraction of ethanol, the mass concentration of the sample, and the sample solution pH, diameter to height ratio, upper column volume, upper column flow rate, eluent concentration, eluent volume and elution flow rate on the purification process, and determine the optimal purification process parameters. Results The best process condition for separating the total flavonoids of Litchi Semen by AB-8 macroporous adsorption resin were as follows: the mass ratio of resin to medicinal material was 3:1, the concentration of the upper column sample solution was 4—6 mg/mL, sample flow rate was 1 mL/min, and the upper column volume was 2 BV, diameter to height ratio was 1∶12, pH of the sample solution was 2, first impurity removal by 20% ethanol 3 BV, and using 60% ethanol 3 BV for elution, elution flow rate was 4 mL/min. Conclusion AB-8 macroporous resin can be used to purify the total flavonoids of Litchi Semen under the established technological conditions. The mass fraction of total flavonoids in Litchi Semen increased from 29.22% to an average of 67.37%, and the solid content decreased from 1.25 g to 0.40 g. It indicates that the established purification process is stable and feasible, and can be used as a purification process condition for total flavonoids of Litchi Semen.

Adsorption kinetics and thermodynamics of phenylethanoid glycosides on macroporous resins in the leaves of Callicarpa nudiflora

Objective: To investigate the adsorption kinetics and thermodynamic characteristics of phenylethanoid glycosides (PGs) in the leaves of Callicarpa nudiflora on macroporous resins and provide a reference for the separation and purification of these compounds. Methods: With adsorption and desorption ratio as indexes, optimum types of macroporous resin for purification of PGs were selected from 8 kinds of macroporous resins by static adsorption and desorption tests, and then adsorption kinetics model and adsorption isotherm model of PGs were established to investigate their adsorption processes. Results: SP-825 and SP-207 resin were selected and they have similar adsorption process for PGs. Both of them showed a fast adsorption in 0-60 min, a slow adsorption in 60-360 min, and an equilibrium adsorption stage after 360 min. Adsorption dynamic behavior was well described by quasi-second-order equation of both SP-825 and SP-207 macroporous resins, and adsorption rate was mainly controlled by liquid film diffusion and intraparticle diffusion. Equilibrium adsorption data fitted Langmuir and Freundlich isotherm equations well. Both of the two kinds of resins showed good adsorption properties for PGs, and the adsorption process belongs to favorable adsorption. Conclusions: Both of the kinetic model and thermodynamic model can well describe the adsorption process of SP-825 and SP-207 macroporous resins and the two resins were regarded as excellent adsorption resins for the purification of PGs from the leaves of Callicarpa nudiflora.