Haiyan Liu

Ficus tikoua Bur., a perennial creeping woody liana belonging to the genus Ficus (Moraceae), has been traditionally used in combination therapies for rheumatoid arthritis (RA). This study aimed to screen active components from F. tikoua Bur. against RA. Prior to activity testing, compounds with appropriate polarity and size were enriched by a homemade β‐cyclodextrin‐based monolithic material when adjusting the polarity of the enrichment mobile phase. Anti‐inflammatory activity evaluations of different fractions were conducted using Cell Counting Kit‐8 (CCK‐8) assay and enzyme‐linked immunosorbent assay (ELISA). Results showed that the compounds in F. tikoua Bur. had no significant effect on RAW264.7 cell viability while effectively reducing secretion levels of inflammatory cytokines IL‐6 and TNF‐α. When a mixture of methanol and water (30:70, v / v ) was used as the enrichment mobile phase, those components adsorbed on the monolith exhibited optimal inhibition effects on IL‐6 and TNF‐α production. Further separation and LC–MS analysis of the most active fraction, combined with literature data, 4‐hydroxy‐3,5‐bis(3′‐methyl‐2‐butenyl) benzoic acid‐O‐β‐D‐glucopyranoside may be the primary anti‐inflammatory constituent. Optimization of enrichment conditions revealed that the monolithic material achieved an enrichment factor of 15.352 for the screened compound.

In present work, a method for enrichment, purification, and content determination of oleanolic acid (OA) in medicinal plants was established based on on-line solid phase extraction (SPE). A metal organic frameworks–porous organic polymer monolith (MOF–POPM) was prepared with functionalized UiO-66-(OH)₂ as monomer and was used as SPE column for online enrichment and purification of OA. The ratio of adsorbent, enriching and eluting solvent, mobile phase pH, and flow rate had been systematically investigated. Under the optimum conditions, the linear range of OA was 0.59–2500 μg/mL with r = 0.9996. The limit of detection (LOD) was 0.18 μg/mL and the limit of quantification (LOQ) was 0.59 μg/mL. The intra-day relative standard deviations (RSDs) and inter-day RSDs of retention time and peak area were less than 0.3% and 1.3%, respectively. The average recoveries of OA in medicinal plants samples ranged from 87.7 to 104.6%. The results demonstrated that the online system was reliable and accurate for enrichment, purification, and content determination of OA in medicinal plants. Graphical abstract

In this study, a poly (IL@MOF) composite monolithic column was synthesized using a simple and easy method. By adjusting the ratio of monomers, porogenic agents and cross‐linking agents, a macroporous composite monolith composed of metal organic framework (MOF) and ionic liquids (IL) was constructed. It was used as a high‐performance solid phase extraction (SPE) sorbent for the extraction of acacetin from medicinal and food homologous plants. The proposed SPE‐HPLC method for determination of acacetin had the advantages of high precision (0.06∼1.00 %), wide linear range (0.01∼250 μg mL ⁻¹ ) and low detection limits (3.26 ng mL ⁻¹ ). The poly (IL@MOF) monolithic column had excellent repeatability as an adsorbent. After 300 adsorption/desorption cycles, the corresponding chromatographic signal had no obvious change. These results indicated that the poly (IL@MOF) composite monolithic column was an ideal adsorbents and that the proposed method had potential for the enrichment and purification of flavonoids from medicinal and food homologous plants.

A metal organic framework (MOF)-based monolithic column was prepared by in situ polymerization using modified MIL-101-NH₂ and glycidyl methacrylate (GMA) as monomers. The monolithic column was used as a solid phase extraction (SPE) adsorbent for on-line enrichment and preliminary purification of diosmetin in traditional Chinese medicine. After being characterized by scanning electron microscopy (SEM) and nitrogen adsorption-desorption, the advantages of the monolithic column with MIL-101-NH₂ added were reflected in the pore structure and specific surface area. The monolithic column for SPE had a linear relationship from 0.13 µg/mL to 5.0 × 10² µg/mL. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.04 µg/mL and 0.13 µg/mL, respectively. The recovery was from 96% to 104%, and the intra-day and inter-day relative standard deviations (RSDs) were below 1.1%. This method was suitable for the determination of diosmetin in complex samples.

A phenyl-based monolithic adsorbent was prepared in a 50-mm-long stainless steel tube, which was initiated by the redox system, using ethylene glycol phenyl ether acrylate as the monomer and ethylene glycol dimethacrylate as the crosslinker. The effects of monomer/crosslinker ratio and the porogens on the permeability and morphology of the resulting adsorbents were investigated, and the optimal adsorbent shows relatively uniform pore structure according to the characterizations of scanning electron microscopy and nitrogen adsorption–desorption method. The column that filled with the adsorbent was used as the solid-phase extraction (SPE) cartridge, exhibiting unique selectivity for the extraction of evodiamine from Euodia fructus (the fruits of Euodia rutaecarpa (Juss.)Benth.), which attributes to the interactions of π-π and hydrogen bonding between the adsorbent and evodiamine. Combined with a C18 analytical column via high-performance liquid chromatography (HPLC) system, an online SPE-HPLC method was established for extraction, enrichment and determination of evodiamine from Euodia fructus. Method validation demonstrates that the relative standard deviation of the precision is less than 0.66%, and the spiked recovery is in the range of 93.11–98.06%. Furthermore, it is worth noting that the prepared SPE cartridge can be reused for no less than 100 times. These results show that the developed method is simple and efficient for online extraction and enrichment of evodiamine from Euodia fructus.

Herein, a poly(ionic liquid@MOF) composite monolithic column was prepared via in situ radical polymerization using ionic liquid (1-allyl-3-methylimidazolium hexafluorophosphate) and MOF (derivatized UIO66-2COOH) as copolymer monomers. The composite monolithic column was characterized via scanning electron microscopy (SEM), nitrogen adsorption–desorption isotherms and mercury intrusion porosimetry. Subsequently, the composite monolithic column combined with high performance liquid chromatography (HPLC) was used as a solid-phase extraction (SPE) absorbent for online purification and enrichment of tectochrysin in medicinal plants. The results indicated that the addition of the ionic liquid and MOF not only increased the surface area but also increased the adsorption capacity of the monolith for tectochrysin. The method showed good linearity in the concentration range of 0.01–500 μg mL⁻¹. The calibration equation was y = 2154.6x − 8.3785 and the limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) were 3.33 ng mL⁻¹ and 10 ng mL⁻¹, respectively. The relative standard deviation (RSD) of the intra-day and inter-day precision was less than 2.62%, the RSD of inter-column was less than 3.16%, and the recoveries ranged from 100.58% to 105.00%. Thus, results showed that this method is simple, accurate and convenient for the online enrichment and purification of tectochrysin from medicinal plants.

A solid‐phase extraction cartridge was fabricated using diallyl isophthalate as the monomer with the addition of porous organic cage material via in situ free‐radical polymerization in a stainless‐steel column. The resulting monolithic adsorbent exhibited a relatively uniform porous structure, a high specific surface area of 113.98 m²/g, and multiple functional chemical groups according to the characterization results. An online solid‐phase extraction–high‐performance liquid chromatography procedure was fabricated to extract and determine tussilagone from Farfarae Flos. The results show that the complex sample matrices can be removed in the solid‐phase extraction procedure. Simultaneously, tussilagone can remain, which can be subsequently switched to an octadecylsilane bonded analytical column. The methodological validation showed that the correlation coefficient was 0.9999 with a linear range of 0.6–200.0 µg/mL, the limit of detection was 0.2 µg/mL, the limit of quantification was 0.6 µg/mL, accuracy was 100.3–100.6%, and relative standard deviation of precision was ≤1.9%. The present monolithic cartridge exhibits good reusability of not more than 100 times. The real sample of Farfarae Flos was determined with a tussilagone content of 0.74 mg/g.