Die Gao

In Vivo Selective Capture and Rapid Identification of Luteolin and Its Metabolites in Rat Livers by Molecularly Imprinted Solid-Phase Microextraction

A method based on molecularly imprinted solid-phase microextraction (MIP-SPME) coupled with liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (QTOF-MS/MS) was developed for the detection of luteolin and its metabolites in vivo. The MIP-SPME fibers were first fabricated by dopamine and silane, and then luteolin MIPs-coated fibers were successfully prepared using luteolin, acrylamide (AM), and ethylene glycol dimethacrylate (EGDMA) as the template, functional monomer and cross-linker, respectively. The characterizations of polymers were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and the Brunauer-Emmett-Teller method (BET). The properties involving adsorption and selective experiments were evaluated, and these results revealed that MIP fibers presented high adsorption capacity and selectivity to luteolin. Furthermore, the developed MIP-SPME coupled with the LC-QTOF-MS/MS method was adopted to capture and identify luteolin and its metabolites in rat livers in vivo, and eventually, apigenin, chrysoeriol, and diosmetin were rapidly identified as metabolites.

Molecularly imprinted polymer for the selective extraction of luteolin from Chrysanthemum morifolium Ramat.

In this work, luteolin-imprinted polymers were prepared by noncovalent precipitation polymerization for the first time. Their structural features and morphologies were analyzed by using Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The adsorption experiments revealed that the luteolin-imprinted polymers presented high selective recognition property to luteolin. The selectivity experiment showed that the adsorption capacity and selectivity of polymers to luteolin was higher than that of three structural analogs, including quercetin, isorhamnetin, and ombuin. Furthermore, an efficient method based on luteolin-imprinted polymers coupled with solid-phase extraction was developed for the pretreatment of luteolin from Chrysanthemum morifolium Ramat. The results demonstrated that the luteolin-imprinted polymers coupled with solid phase extraction method was proven to be a potentially competitive technique for the separation and enrichment of luteolin in complex samples such as Chinese patent medicines and biological samples.

Molecularly imprinted polymers for the selective extraction of tiliroside from the flowers of Edgeworthia gardneri (wall.) Meisn

Nano-sized molecularly imprinted polymers for tiliroside were successfully prepared by a precipitation polymerization method. Acrylamide, ethylene glycol dimethacrylate, azobisisobutyronitrile, and acetonitrile/dimethyl sulfoxide were used as functional monomer, cross-linker, initiator, and porogen, respectively. The structural features and morphological characterization of tiliroside-imprinted polymers were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The adsorption experiments indicated that the tiliroside-imprinted polymers exhibited high selective recognition property to tiliroside. Scatchard analysis indicated that the homogeneous-binding sites were formed in the polymers. The selectivity test revealed that the adsorption capacity and selectivity of polymers to tiliroside was significantly higher than that of rutin, astragalin, and kaempferol. Finally, the tiliroside-imprinted polymers were employed as adsorbents in solid-phase extraction for the extraction of tiliroside from the ethyl acetate extract of the flowers of Edgeworthia gardneri (wall.) Meisn. The results demonstrated that the extraction recoveries of tiliroside ranged from 69.3 to 73.5% by using tiliroside-imprinted polymers coupled with solid-phase extraction method. These results indicated that the tiliroside-based molecularly imprinted solid-phase extraction method was proven to be an effective technique for the separation and enrichment of tiliroside from natural medicines.

A New γ-Pyrone from Ampelocissus artemisiifolia

Phytochemical investigation of Ampelocissus artemisiifolia Planch. led to the isolation of a new γ-pyrone,(E)-2-(2-hydroxypropyl)-6-(4-hydroxystyryl)-4H-pyran-4-one (1), together with eight known compounds (2–9). Their structures were identified on the basis of spectroscopic analysis and by comparison of their spectral data with those reported in the literature. All of them were isolated from the genus Ampelocissus for the first time, while compounds 7, 8, and 9 were new for the family Vitaceae.

Magnetic molecularly imprinted polymer for the selective extraction of hesperetin from the dried pericarp of Citrus reticulata Blanco

In present study, novel magnetic molecularly imprinted polymers for hesperetin were successfully prepared by surface molecular imprinting method using functionalized Fe3O4 particles as the magnetic cores. Hesperetin as the template, N-Isopropylacrylamide as the functional monomer, ethylene glycol dimethyl acrylate as the crosslinker, 2,2-azobisisobutyonnitrile as initiator and acetonitrile-methanol (3:1, v/v) as the porogen were applied in the preparation process. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscope, x-ray diffraction and vibrating sample magnetometry were applied to characterize the magnetic molecularly imprinted polymers. The adsorption experiments indicated that the magnetic molecularly imprinted polymers performed high selective recognition property to hesperetin. The selectivity experiment indicated that the adsorption capacity and selectivity of polymers to hesperetin was higher than that of luteolin, baicalein and ombuin. Furthermore, the magnetic molecularly imprinted polymers were employed as adsorbents for extraction and enrichment of hesperetin from the dried pericarp of Citrus reticulata Blanco. The recoveries of hesperetin in the dried pericarp of Citrus reticulata Blanco ranged from 90.5% to 96.9%. The linear range of 0.15-110.72 µg/mL was obtained with correlation coefficient of greater than 0.9991. The limit of detection and quantification of the proposed method was 0.06 µg/mL and 0.15 µg/mL, respectively. Based on three replicate measurements, intra-day RSD was 0.71% and inter-day RSD was 2.31%. These results demonstrated that the prepared magnetic molecularly imprinted polymers were proven to be an effective material for the selective adsorption and enrichment of hesperetin from natural medicines, fruits and et al.

Mixed-mode liquid chromatography with a stationary phase co-functionalized with ionic liquid embedded C18 and an aryl sulfonate group

A novel silica stationary phase was designed and prepared through thiol-ene click chemistry by functionalizing imidazolium based ionic liquid embedded C18 and an aryl sulfonate group for the mixed-mode liquid chromatography. The developed stationary phase was characterized by elemental analysis (EA), Fourier transform infrared spectrometry (FT-IR) and thermogravimetric analysis (TGA). The chromatographic performances of the prepared column were investigated by reversed phase chromatography using alkylbenzenes and positional isomers, hydrophilic interaction chromatography using nucleosides, nucleic bases and flavonoids, and ion exchange chromatography using acidic and basic analytes. The stationary phase showed faster separation and better performance for these compounds compared to the conventional alkyl stationary phase, especially for the separation of positional isomers. The investigations about water percentage and pH of the mobile phase for retentions provided information that the stationary phase offered multiple interactions with samples including hydrophobic, hydrophilic and electrostatic interactions. Moreover, improved separation efficiency of Qinghuozhimai tablet and vitamin B2 tablet were successfully achieved respectively on a single mixed-mode column. In conclusion, the multimodal retention capabilities of the developed stationary phase could offer flexible selectivity toward various types of compounds and complex samples.

In vitro screening and evaluation of 37 traditional chinese medicines for their potential to activate peroxisome proliferator-activated receptors-γ

Background: Peroxisome proliferator-activated receptors (PPAR)-γ is widely used as an attractive target for the treatment of type 2 diabetes mellitus. Thiazolidinediones, the agonists of PPARγ, has been popularly utilized as insulin sensitizers in the therapy of type 2 diabetes whereas numerous severe side-effects may also occur concomitantly. Objective: The PPARγ activation activity of different polar extracts, including petroleum ether, ethyl acetate, n-butanol, residual of ethanol, the precipitate part of water and the supernatant of water extracts, from 37 traditional Chinese medicines were systematically evaluated. Materials and Methods: HeLa cells were transiently co-transfected with the re-constructed plasmids of GAL4-PPARγ-ligand binding domain and pGL4.35. The activation of PPARγ by different polarity extracts were evaluated based on the PPARγ transactivation assay and rosiglitazone was used as positive control. Results: Seven medicines (root bark of Lycium barbarum, Anoectochilus sroxburghii, the rhizome of Phragmites australis, Pterocephalus hookeri, Polygonatum sibiricum, fruit of Gleditsia sinensis, and Epimedium brevicornu) were able to significantly activate PPARγ. Conclusion: As seven medicines were able to activate PPARγ, the anti-diabetic activity of them is likely to be mediated by this nuclear receptor.

Rapid synthesis of three-dimensional sulfur-doped porous graphene via solid-state microwave irradiation for protein removal in plasma sample pretreatment

In this work, we prepared three-dimensional sulfur-doped porous graphene (3D-SPG) via solid-state microwave method and first introduced it to plasma sample pretreatment as adsorbent for the removal of proteins. The efficient heating effect of solid-state microwave irradiation endowed the as-prepared 3D-SPG with large specific surface area, porous structures and sulfur-doped conjugated π electron surface, thus producing an outstanding adsorbent for proteins adsorption. The adsorption behavior of 3D-SPG towards proteins was explored using bovine serum albumin (BSA) as the model protein and several kinetic models and isotherm models were employed to describe the adsorption process. The results indicated that BSA was adsorbed onto 3D-SPG in a monolayer manner with high adsorption capacity, and chemisorption and intraparticle diffusion was the rate-controlling step in proteins adsorption process. By applying 3D-SPG as adsorbent to remove proteins in real rat plasma, we found that 3D-SPG solid phase extraction (SPE) gained exceedingly high protein removal efficiency compared with other plasma pretreatment methods, suggesting that 3D-SPG SPE could effectively prevent the deterioration of column performance and decrease the interference caused by matrix effect in the follow-up analysis. Furthermore, in comparison with the tandem mass spectra results between 3D-SPG SPE and methanol precipitation, 3D-SPG SPE demonstrated the ability to extract the protein-binding metabolites which usually could not be extracted by methanol precipitation. This ability made 3D-SPG SPE of great value in untargeted metabolomics profiling, because 3D-SPG SPE could be a complementary method to methanol precipitation to improve the coverage of metabolites.

Comparing coagulation activity of Selaginella tamariscina before and after stir-frying process and determining the possible active constituents based on compositional variation

Abstract Context: Selaginella tamariscina (P. Beauv.) Spring (Selaginellaceae) (ST) has been widely used in China as a medicine for improving blood circulation. However, its processed product, S. tamariscina carbonisatus (STC), possesses opposite haemostatic activity. Objective: To comprehensively evaluate the activity of ST and STC on physiological coagulation system of rats, and seek potential active substances accounting for the activity transformation of ST during processing. Materials and methods: The 75% methanol extracts of the whole grass (fine powder) of ST and STC were prepared, respectively. Male Sprague–Dawley rats were randomly divided into five groups: control group, model group, model + ST group, model + STC group and positive control group (model + Yunnanbaiyao). The duration of intragastric administration was 72 h at 12 h intervals. Haemorheology parameters were measured using an LB-2 A cone-plate viscometer and the existed classic methods, respectively. SC40 semi-automatic coagulation analyzer was employed to determine coagulation indices. Meanwhile, HPLC and LC-MS were applied for chemical analyses of ST and STC extracts. Results: STC shortened tail-bleeding time, increased whole blood viscosity (WBV) and plasma viscosity (PV), decreased erythrocyte sedimentation rate blood (ESR), reduced activated partial thromboplastin time (APTT) and increased the fibrinogen (FIB) content in the plasma of bleeding model rats. Although ST could shorten APTT and TT, the FIB content was significantly decreased by ST. Dihydrocaffeic acid with increased content in STC vs. ST showed haemostatic activity for promoting the platelet aggregation induced by collagen and trap-6, and reducing APTT and PT significantly with a concentration of 171.7 μM in vitro. Amentoflavone with reduced content in STC vs. ST inhibited ADP and AA-induced platelet aggregation significantly with a concentration of 40.7 μM. Discussion and conclusions: As the processed product of ST, STC showed strong haemostatic activity on bleeding rat through regulating the parameters involved in haemorheology and plasma coagulation system. Two active compounds, dihydrocaffeic acid and amentoflavone, might be partially responsible for the haemostatic and anticoagulant activity of STC and ST, respectively.

Novel dual functional monomers based molecularly imprinted polymers for selective extraction of myricetin from herbal medicines

Herein, novel dual functional monomers based molecularly imprinted polymers (MIPs) were successfully prepared and used to extract myricetin from Carthamus tinctorius L., also named safflower (family, Compositae) and the flower of Abelmoschus manihot (Linn.) Medicus (family, Malvaceae). The polymers were prepared using myricetin as template, 4-vinylpyridine (4-VP) and glycidyl methacrylate (GMA) as dual functional monomers, ethylene glycol dimethyl acrylate (EGDMA) as cross-linker and methanol-acetonitrile (1:2, v/v) as solvent, respectively. Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were applied to characterize the polymers. Further, the adsorption and selectivity experiments of MIPs were evaluated. The results revealed that MIPs showed high adsorption ability and selectivity toward myricetin. Finally, MIPs were employed as adsorbents for solid phase extraction (SPE) of myricetin from safflower and the flowers of A. manihot (Linn.) Medicus. Further analysis was conducted by using high performance liquid chromatography-diode array detection (HPLC-DAD). The recovery of mrricetin in safflower and in the flowers of A. manihot ranged from 79.82% to 83.91%, 81.50% to 84.32%, respectively. These results indicated that MIPs can be applied to the extraction and separation of myricetin from various complex matrixes.