Lujun Wang

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.

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.

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.

Preparation and evaluation of a reversed-phase/hydrophilic interaction/ion-exchange mixed-mode chromatographic stationary phase functionalized with dopamine-based dendrimers

In this work, a novel dendritic stationary phase was synthesized by the repeated grafting of 1,4-butanediol diglycidyl ether (BDDE) and dopamine (DA) on the surface of silica for performing mixed-mode high-performance liquid chromatography (MHPLC). Elemental analysis (EA), thermogravimetric analysis (TGA) and Fourier transform infrared spectrometry (FT-IR) showed the successful preparation of the dendritic stationary phase. The prepared stationary phase showed the retention mechanisms of reversed-phase liquid chromatography (RPLC), hydrophilic interaction chromatography (HILIC) and ion-exchange chromatography (IEC) under different mobile phase conditions. In detail, alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs) and hydrophobic positional isomers were separated successfully in the RPLC mode. The baseline separation of nucleobases, nucleosides and flavonoids was achieved under HILIC mode, respectively. Meanwhile, some acidic and basic analytes were used to evaluate the IEC mode. The effects of different chromatographic conditions, such as acetonitrile content, salt concentration and pH in the mobile phase, on the different chromatographic modes were also investigated. In addition, the application of the mixed-mode dendritic stationary phase was demonstrated by the analysis of traditional Chinese medicine (TCM), including Carthamus tinctorius L. and Abelmoschus manihot (Linn.) Medicus. Interestingly, the stationary phase also has the ability for the capture and separation of boric acids. These meaningful applications confirmed that the mixed-mode dendritic stationary phase can be potentially applied in the analysis of complex samples.

Preparation of a poly(ethyleneimine) embedded phenyl stationary phase for mixed-mode liquid chromatography

A poly(ethyleneimine) embedded phenyl mixed-mode stationary phase was prepared through epoxide ring opening reaction. Elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to characterize whether functional groups have been modified on the surface of silica successfully. The researches of chromatographic performance for designed column were divided to four parts. The retention behavior under reversed-phase mode was studied using polycyclic aromatic hydrocarbons (PAHs), positional isomers and alkylbenzenes. The retention characteristic under hydrophilic interaction mode was studied by nucleosides, nucleobases and flavonoids. The chromatographic performance of anion exchange mode was evaluated by benzoic acids and phenols. Due to a high content of amino and phenyl groups on the stationary phase, aromatic amines were chosen for the evaluation of retention mechanisms of benzene ring attraction and amino repulsion. The investigations about effects of mobile phase constitution and pH on retention demonstrated the mixed-mode retention mechanisms of the column. Furthermore, due to amino selectivity of the column, a method for the rapid separation and determination of phenylenediamines in hair dye was established. And both linear correlation coefficients of p-diaminobenzene and m-diaminobenzene in concentration range from 0.1 to 30 μg mL-1 were over 0.999. In conclude, the prepared mixed-mode stationary phase could realize various separation modes by adjusting chromatographic conditions, and it had the potential for the rapid separation and determination of aniline compounds in various complex samples.

Chemical Constituents of Pouzolzia zeylanica with PPARγ and PPARβ Activities

Pouzolzia zeylanica is a flowering plant belonging to the Urticaceae family that is widely distributed throughout China, where it grows in the mountains and on the roadside. Pouzolzia zeylanica has been used for centuries in traditional Chinese medicine for the treatment of different diseases, including acute mastitis, pyogenic infection, dysentery, indigestion, abdominal pain, infantile malnutrition, edema, dysuria, bruises, hemoptysis, hematemesis, and traumatic hemorrhage [1, 2]. Despite its use as a traditional Chinese medicine, there have been very few reports in the literature on the chemical composition of P. zeylanica. With this in mind, we conducted a phytochemical study of P. zeylanica, which resulted in the isolation and subsequent identification of 11 compounds 1–11, including N-[2-(3-hydroxy-4-methoxyphenyl)-2-hydroxyethyl]-3-(4methoxyphenyl)prop-2-enamide (1), 14,16-hentriacontanedione (2), sinapaldehyde (3), 3,4-dihydro-5,7-dihydroxy-4-(4hydroxyphenyl)coumarin (4), kaempferol (5), quercetin (6), stigmast-4-en-3-one (7), undecyl ferulate (8), -sitosterol (9), syringaresinol (10), and dipentylphthalate (11). Notably, this article represents the first reported example of the isolation of compounds 1–5, 7, 8, 10, and11 from P. zeylanica, as well as the first reported example of the isolation of compounds 1, 2, and 4 from a plant belonging to the Urticaceae family. The PPAR and PPAR activities of compounds 1–11 were evaluated using a luciferase reporter assay, and the results showed that some of these compounds exhibited reasonable levels of activity. Plant Material and Apparatus. Plant materials were purchased from An Guo Chang An Chinese Medicinal Herbs Company (Chongqing, China) in October 2011. The authenticity of the plant material was confirmed by Songyun Qin (research assistant) at the Chongqing Academy of Chinese Materia Medica, China. A voucher specimen of the plant material was also