Ectopic Production of 3,4-Dihydroxybenzoate in Planta Affects Cellulose Structure and Organization.

Lignocellulosic biomass is a highly sustainable and largely carbon dioxide neutral feedstock for the production of biofuels and advanced biomaterials. Although thermochemical pretreatment is typically used to increase the efficiency of cell wall deconstruction, genetic engineering of the major plant cell wall polymers, especially lignin, has shown promise as an alternative approach to reduce biomass recalcitrance. Poplar trees with reduced lignin content and altered composition were previously developed by overexpressing bacterial 3-dehydroshikimate dehydratase (QsuB) enzyme to divert carbon flux from the shikimate pathway. In this work, three transgenic poplar lines with increasing QsuB expression levels and different lignin contents were studied using small-angle neutron scattering (SANS) and wide-angle X-ray scattering (WAXS). SANS showed that although the cellulose microfibril cross-sectional dimension remained unchanged, the ordered organization of the microfibrils progressively decreased with increased QsuB expression. This was correlated with decreasing total lignin content in the QsuB lines. WAXS showed that the crystallite dimensions of cellulose microfibrils transverse to the growth direction were not affected by the QsuB expression, but the crystallite dimensions parallel to the growth direction were decreased by ∼20%. Cellulose crystallinity was also decreased with increased QsuB expression, which could be related to high levels of 3,4-dihydroxybenzoate, the product of QsuB expression, disrupting microfibril crystallization. In addition, the cellulose microfibril orientation angle showed a bimodal distribution at higher QsuB expression levels. Overall, this study provides new structural insights into the impact of ectopic synthesis of small-molecule metabolites on cellulose organization and structure that can be used for future efforts aimed at reducing biomass recalcitrance.

Poly(2-oxazoline)s Based on Phenolic Acids.

A series of phenolic-acid-based 2-oxazoline monomers with methoxy-substituted phenyl and cinnamyl side chains is synthesized and polymerized in a microwave reactor at 140 °C using methyl tosylate as the initiator. The obtained poly(2-oxazoline)s are characterized by NMR spectroscopy, MALDI-TOF mass spectrometry, and size-exclusion chromatography (SEC). Kinetic studies reveal that the microwave-assisted polymerization is fast and completed within less than ≈10 min for low monomer-to-initiator ratios of ≤25. Polymers with number-average molar masses of up to 6500 g mol-1 and low dispersity (1.2-1.3) are produced. The aryl methyl ethers are successfully cleaved with aluminum triiodide/N,N'-diisopropylcarbodiimide to give a poly(2-oxazoline) with pendent catechol groups.

Morphological Changes and Cellular Uptake of Functionalized Graphene Oxide Loaded with Protocatechuic Acid and Folic Acid in Hepatocellular Carcinoma Cancer Cell.

The development of nanocomposites has swiftly changed the horizon of drug delivery systems in defining a new platform. Major understanding of the interaction of nanocomposites with cells and how the interaction influences intracellular uptake is an important aspect to study in order to ensure successful utilisation of the nanocomposites. Studies have suggested that the nanocomposites' ability to permeate into biological cells is attributable to their well-defined physicochemical properties with nanoscale size, which is relevant to the nanoscale components of biology and cellular organelles. The functionalized graphene oxide coated with polyethylene glycol, loaded with protocatechuic acid and folic acid (GOP-PCA-FA) nanocomposite intracellular uptake was analysed using transmission electron microscope. The accumulation of fluorescent-labelled nanocomposites in the HepG2 cell was also analysed using a fluorescent microscope. In vitro cellular uptake showed that there was uptake of the drug from 24 h into the cells and the release study using fluorescently tagged nanocomposite demonstrated that release and accumulation were observed at 24 h and 48 h. Moreover, the migration ability of tumor cells is a key step in tumor progression which was observed 48 h after treatment. The GOP serves as a potential nanocarrier system which is capable of improving the therapeutic efficacy of drugs and biomolecules in medical as well as pharmaceutical applications through the enhanced intracellular release and accumulation of the encapsulated drugs. Nonetheless, it is essential to analyse the translocation of our newly developed GOP-PCA-FA, and its efficiency for drug delivery, effective cellular uptake, and abundant intracellular accumulation would be compromised by possible untoward side effects.

Screening Libraries of Amphiphilic Janus Dendrimers Based on Natural Phenolic Acids to Discover Monodisperse Unilamellar Dendrimersomes.

Natural, including plant, and synthetic phenolic acids are employed as building blocks for the synthesis of constitutional isomeric libraries of self-assembling dendrons and dendrimers that are the simplest examples of programmed synthetic macromolecules. Amphiphilic Janus dendrimers are synthesized from a diversity of building blocks including natural phenolic acids. They self-assemble in water or buffer into vesicular dendrimersomes employed as biological membrane mimics, hybrid and synthetic cells. These dendrimersomes are predominantly uni- or multilamellar vesicles with size and polydispersity that is predicted by their primary structure. However, in numerous cases, unilamellar dendrimersomes completely free of multilamellar assemblies are desirable. Here, we report the synthesis and structural analysis of a library containing 13 amphiphilic Janus dendrimers containing linear and branched alkyl chains on their hydrophobic part. They were prepared by an optimized iterative modular synthesis starting from natural phenolic acids. Monodisperse dendrimersomes were prepared by injection and giant polydisperse by hydration. Both were structurally characterized to select the molecular design principles that provide unilamellar dendrimersomes in higher yields and shorter reaction times than under previously used reaction conditions. These dendrimersomes are expected to provide important tools for synthetic cell biology, encapsulation, and delivery.

Dual Drugs Anticancer Nanoformulation using Graphene Oxide-PEG as Nanocarrier for Protocatechuic Acid and Chlorogenic Acid.

BACKGROUND: The chemotherapy of cancer has been complicated by poor bioavailability, adverse side effects, high dose requirement, drug resistance and low therapeutic indices. Cancer cells have different ways to inhibit the chemotherapeutic drugs, use of dual/multiple anticancer agents may be achieve better therapeutic effects in particular for drug resistant tumors. Designing a biocompatible delivery system, dual or multiple drugs could addressing these chemotherapy drawbacks and it is the focus of many current biomedical research. METHODS: In the present study, graphene oxide-polyethylene glycol (GOPEG) nanocarrier is designed and loaded with two anticancer drugs; Protocatechuic acid (PCA) and Chlorogenic acid (CA). The designed anticancer nanocomposite was further coated with folic acid to target the cancer cells, as their surface membranes are overexpressed with folate receptors. RESULTS: The particle size distribution of the designed nanocomposite was found to be narrow, 9-40 nm. The release profiles of the loaded drugs; PCA and CA was conducted in human body simulated PBS solutions of pH 7.4 (blood pH) and pH 4.8 (intracellular lysosomal pH). Anticancer properties were evaluated against cancerous cells i.e. liver cancer, HEPG2 and human colon cancer, HT-29 cells. The cytocompatbility was assessed on normal 3T3 fibroblasts cells. CONCLUSION: The size of the final designed anticancer nanocomposite formulation, GOPEG-PCACA-FA was found to be distributed at 9-40 nm with a median of 8 nm. The in vitro release of the drugs PCA and CA was found to be of sustained manner which took more than 100 h for the release. Furthermore, the designed formulation was biocompatible with normal 3T3 cells and showed strong anticancer activity against liver and colon cancer cells.

Towards A New Approach for the Description of Cyclo⁻2,4-Dihydroxybenzoate, A Substance Which Effectively Mimics Zearalenone in Imprinted Polymers Designed for Analyzing Selected Mycotoxins in Urine.

A method of purifying cyclododecyl 2,4-dihydroxybenzoate as a potential replacement template molecule for preparation of molecularly-imprinted polymers for isolation of zearalenone in urine was developed. Full physicochemical characteristics of cyclododecyl 2,4-dihydroxybenzoate for the first time included crystallographic analysis and molecular modelling, which made possible the determination of the similarity between the cyclododecyl 2,4-dihydroxybenzoate and zearalenone molecules. The obtained molecularly-imprinted polymers show very high in vitro selectivity towards zearalenone due to specific interactions (e.g., hydrogen bonding, molecular recognition interaction). The achieved extraction recovery exceeds 94% at the tested concentration levels (20⁻500 ng·mL-1) with a relative standard deviation below 2%. Immunosorbents were found to have lower recoveries (below 92.5%) and RSD value between 2 and 4% for higher concentrations of the studied substance (400 ng·mL-1).

Highly selective and efficient imprinted polymers based on carboxyl-functionalized magnetic nanoparticles for the extraction of gallic acid from pomegranate rind.

With the combined surface imprinting technique and immobilized template strategy, molecularly imprinted magnetic nanoparticles were successfully prepared and coupled with high-performance liquid chromatography to selectively separate and determine gallic acid from the pomegranate rind. On the surface of carboxyl-functionalized magnetic nanospheres, thin imprinting shells were formed using dopamine as monomer and crosslinker. The characteristics, polymerization conditions, and adsorption performances of the resultant nanomaterials were investigated in detail. In addition of good crystallinity, satisfactory magnetism, and uniform morphology of the obtained polymers, they had rapid binding kinetics, high adsorption capacity, and favorable reusability. In the mixed solution of four hydroxybenzoic acids, the prepared nanomaterials have an excellent selectivity to gallic acid with an imprinting factor of as high as 17.5. Therefore, the polymers have great potentials in specific extraction and enrichment of gallic acid from the complex natural resources.

Automated solid-phase extraction of phenolic acids using layered double hydroxide-alumina-polymer disks.

The application of layered double hydroxide-Al2 O3 -polymer mixed-matrix disks for solid-phase extraction is reported for the first time. Al2 O3 is embedded in a polymer matrix followed by an in situ metal-exchange process to obtain a layered double hydroxide-Al2 O3 -polymer mixed-matrix disk with excellent flow-through properties. The extraction performance of the prepared disks is evaluated as a proof of concept for the automated extraction using sequential injection analysis of organic acids (p-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid) following an anion-exchange mechanism. After the solid-phase extraction, phenolic acids were quantified by reversed-phase high-performance liquid chromatography with diode-array detection using a core-shell silica-C18 stationary phase and isocratic elution (acetonitrile/0.5% acetic acid in pure water, 5:95, v/v). High sensitivity and reproducibility were obtained with limits of detection in the range of 0.12-0.25 µg/L (sample volume, 4 mL), and relative standard deviations between 2.9 and 3.4% (10 µg/L, n = 6). Enrichment factors of 34-39 were obtained. Layered double hydroxide-Al2 O3 -polymer mixed-matrix disks had an average lifetime of 50 extractions. Analyte recoveries ranged from 93 to 96% for grape juice and nonalcoholic beer samples.

Peracetic Acid Depolymerization of Biorefinery Lignin for Production of Selective Monomeric Phenolic Compounds.

Lignin is the largest source of renewable material with an aromatic skeleton. However, due to the recalcitrant and heterogeneous nature of the lignin polymer, it has been a challenge to effectively depolymerize lignin and produce high-value chemicals with high selectivity. In this study, a highly efficient lignin-to-monomeric phenolic compounds (MPC) conversion method based on peracetic acid (PAA) treatment was reported. PAA treatment of two biorefinery lignin samples, diluted acid pretreated corn stover lignin (DACSL) and steam exploded spruce lignin (SESPL), led to complete solubilization and production of selective hydroxylated monomeric phenolic compounds (MPC-H) and monomeric phenolic acid compounds (MPC-A) including 4-hydroxy-2-methoxyphenol, p-hydroxybenzoic acid, vanillic acid, syringic acid, and 3,4-dihydroxybenzoic acid. The maximized MPC yields obtained were 18 and 22 % based on the initial weight of the lignin in SESPL and DACSL, respectively. However, we found that the addition of niobium pentoxide catalyst to PAA treatment of lignin can significantly improve the MPC yields up to 47 %. The key reaction steps and main mechanisms involved in this new lignin-to-MPC valorization pathway were investigated and elucidated.

Synthesis of mono Mannich bases of 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one and evaluation of their cytotoxicities.

Chalcones and Mannich bases are a group of compounds known for their cytotoxicities. In this study restricted chalcone analogue, compound 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one MT1, was used as a starting compound to synthesize new mono Mannich bases since Mannich bases may induce more cytotoxicity than chalcone analogue that they are derived from by producing additional alkylating center for cellular thiols. In this study, cyclic and acyclic amines were used to synthesize Mannich bases. All compounds were tested against Ca9-22 (gingival carcinoma), HSC-2, HSC-3 and HSC-4 (oral squamous cell carcinoma) as tumour cell lines and HGF (gingival fibroblasts), HPC (pulp cells) and HPLF (periodontal ligament fibroblasts) human normal oral cells as non tumour cell lines. Cytotoxicity, selectivity index (SI) values and potency selectivity expression (PSE) values expressed as a percentage were determined for the compounds. According to data obtained, the compound MT8 with the highest PSE value bearing N-methylpiperazine moiety seems to be a good candidate to develop new cytotoxic compounds and is suited for further investigation.

Antibiotic activity of iron-sequestering polymers.

Increasing antibiotic resistance has compelled the development of novel antibiotics and adjuvant therapies that enhance the efficacy of existing antibiotics. Iron plays a critical role in bacterial infections, yet the use of iron chelators as adjuvant therapy with antibiotics has yielded highly variable outcomes. Multivalent polymeric materials offer an alternative approach to bind and sequester iron via high avidity interactions. Here, a biomimetic iron-sequestering polymer (PAI-DHBA) was synthesized by modifying side chains of cross-linked polyallylamine (cPAI) with 2,3-dihydroxybenzoic acid (DHBA). PAI-DHBA polymer gels with various DHBA contents showed high iron affinity indices and high selectivity for iron. The polymers showed mild antibiotic properties when used to treat established bacterial cultures. Pretreating culture media with PAI-DHBA polymer, however, removed all detectable iron from media and effectively inhibited the growth of Pseudomonas aeruginosa. In addition, bacterial growth was more susceptible to antibiotics combined with PAI-DHBA. Multivalent polymers that bind and sequester iron, such as PAI-DHBA, offer a promising early intervention or adjuvant to antibiotics.

Mimicking the hierarchical functions of dentin collagen cross-links with plant derived phenols and phenolic acids.

Proanthocyanidins (PACs) are secondary plant metabolites that mediate nonenzymatic collagen cross-linking and enhance the properties of collagen based tissue, such as dentin. The extent and nature of cross-linking is influenced by the composition and specific chemical structure of the bioactive compounds present in certain PAC-rich extracts. This study investigated the effect of the molecular weight and stereochemistry of polyphenol compounds on two important properties of dentin, biomechanics, and biostability. For that, purified phenols, a phenolic acid, and some of its derivatives were selected: PAC dimers (A1, A2, B1, and B2) and a trimer (C1), gallic acid (Ga), its esters methyl-gallate (MGa) and propyl-gallate (PGa), and a pentagalloyl ester of glucose (PGG). Synergism was assessed by combining the most active PAC and gallic acid derivative. Mechanical properties of dentin organic matrix were determined by the modulus of elasticity obtained in a flexural test. Biostability was evaluated by the resistance to collagenase degradation. PACs significantly enhanced dentin mechanical properties and decreased collagen digestion. Among the gallic acid derivatives, only PGG had a significant enhancing effect. The lack of observed C1:PGG synergy indicates that both compounds have similar mechanisms of interaction with the dentin matrix. These findings reveal that the molecular weight of polyphenols have a determinant effect on their interaction with type I collagen and modulates the mechanism of cross-linking at the molecular, intermolecular, and inter-microfibrillar levels.

Effects of aromatic compounds on the production of bacterial nanocellulose by Gluconacetobacter xylinus.

BACKGROUND: Bacterial cellulose (BC) is a polymeric nanostructured fibrillar network produced by certain microorganisms, principally Gluconacetobacter xylinus. BC has a great potential of application in many fields. Lignocellulosic biomass has been investigated as a cost-effective feedstock for BC production through pretreatment and hydrolysis. It is well known that detoxification of lignocellulosic hydrolysates may be required to achieve efficient production of BC. Recent results suggest that phenolic compounds contribute to the inhibition of G. xylinus. However, very little is known about the effect on G. xylinus of specific lignocellulose-derived inhibitors. In this study, the inhibitory effects of four phenolic model compounds (coniferyl aldehyde, ferulic acid, vanillin and 4-hydroxybenzoic acid) on the growth of G. xylinus, the pH of the culture medium, and the production of BC were investigated in detail. The stability of the phenolics in the bacterial cultures was investigated and the main bioconversion products were identified and quantified. RESULTS: Coniferyl aldehyde was the most potent inhibitor, followed by vanillin, ferulic acid, and 4-hydroxybenzoic acid. There was no BC produced even with coniferyl aldehyde concentrations as low as 2 mM. Vanillin displayed a negative effect on the bacteria and when the vanillin concentration was raised to 2.5 mM the volumetric yield of BC decreased to ~40% of that obtained in control medium without inhibitors. The phenolic acids, ferulic acid and 4-hydroxybenzoic acid, showed almost no toxic effects when less than 2.5 mM. The bacterial cultures oxidized coniferyl aldehyde to ferulic acid with a yield of up to 81%. Vanillin was reduced to vanillyl alcohol with a yield of up to 80%. CONCLUSIONS: This is the first investigation of the effect of specific phenolics on the production of BC by G. xylinus, and is also the first demonstration of the ability of G. xylinus to convert phenolic compounds. This study gives a better understanding of how phenolic compounds and G. xylinus cultures are affected by each other. Investigations in this area are useful for elucidating the mechanism behind inhibition of G. xylinus in lignocellulosic hydrolysates and for understanding how production of BC using lignocellulosic feedstocks can be performed in an efficient way.

pH and effects on Streptococcus mutans growth of denture adhesives: an in vitro study.

OBJECTIVES: To evaluate the pH and effects on Streptococcus mutans growth of denture adhesives. BACKGROUND: There is little information regarding the pH of contemporary adhesives and their influences on S. mutans growth. MATERIALS AND METHODS: The adhesives tested were Polident® cream, Protefix® cream and Protefix® powder. Samples of each adhesive were added to deionized water to produce solutions of 10.0, 5.0, 2.5 and 1.0% w/v (cream formulations) or 5.0, 2.5,1.0 and 0.5% (powder formulation). The pH values were measured immediately after preparation and at 1-, 2-, 3-, 6-, 12-, and 24-h intervals using a digital pH meter. Streptococcus mutans UA159 was inoculated in the Brain Heart Infusion medium with or without the adhesive extracts (control). Bacterial growth was observed by measuring absorption at 600 nm every 1 h for 12 h using a spectrophotometer. RESULTS: The tested adhesives generally remained relatively pH-stable over 24 h, ranging from 5.5 to 7.0. There were no statistically significant differences in S. mutans growth rates between the extract-treated and control cultures (p>0.5). CONCLUSIONS: Some adhesives produce a pH below the critical pH of hydroxyapatite and may not be suitable for patients with natural teeth. None of the tested adhesives significantly affect S. mutans growth.

Modified chitosan with different phenolic acids: Characterization, physicochemical properties, and biological activity.

This study synthesized five phenolic acid-chitosan copolymers utilizing the carbodiimide-mediated chemical crosslinking reaction. Comprehensive evaluations were conducted on their structural attributes, physicochemical properties, and biological activities. Fourier transform infrared confirmed successful grafting of phenolic acids onto chitosan via amide linkages. Additionally, ultraviolet-visible absorption spectroscopy and proton nuclear magnetic resonance analyses revealed novel absorption peaks between 200 and 400 nm and 6.0-8.0 ppm, respectively, attributable to the incorporated phenolic acids. Notably, the chitosan-gentisate acid copolymer exhibited significantly enhanced biological activity (p < 0.05) compared to pure chitosan and the other four conjugates, attributed to its highest grafting degree of approximately 295.93 mg/g. These modified chitosan derivatives effectively preserved the quality of sea bass (Lateolabrax japonicus) during refrigerated storage, extending its shelf-life by up to 9 days, 7 days, and 4 days relative to control, chitosan, and gentisate acid groups.

Selective extraction and analysis of phenolic acids in herbal plants using Fe3O4@MXene@PEI aerogel.

A magnetic MXene aerogel (Fe3O4@MXene@PEI) was prepared by crosslinking amino modified MXene with polyethyleneimine using epichlorohydrin as a cross-linker. Adsorption properties of Fe3O4@MXene@PEI aerogel for phenolic acids were evaluated by adsorption kinetics and isotherms experiments, showing that the high adsorption affinity was governed by multilayer chemisorption process. An efficient MSPE/HPLC method was developed for the determination of phenolic acids with excellent selectivity, good linearity (0.025-5.0 µg mL-1), low LODs (0.007-0.017 µg mL-1), and satisfactory recoveries (80.0-120.0 %). Moreover, the antioxidant activity of the Fe3O4@MXene@PEI purified compounds was superior to that of the conventional method as demonstrated by the results of scavenging experiments on 2,2 -diphenyl-1-picrylhydrazyl radical scavenging assay. Finally, 65 organic acids were identified in the Fe3O4@MXene@PEI treated honeysuckle extracts by UHPLC-Q-Exactive Orbitrap MS/MS analysis. The proposed sorbent exhibits remarkable promise for the selective separation and purification of organic acids from herbal products.

Multifunctional protocatechuic acid-polyacrylic acid hydrogel adhesives for wound dressings.

Multifunctional hydrogel adhesives are highly desirable in wound healing applications, yet their preparation often requires complex material system design to achieve. Herein, a straightforward one-pot two-step polymerization method is developed to prepare adhesive hydrogels for wound dressing based on protocatechuic acid (PCA), polyacrylic acid (PAA), and polyamidoamine-epichlorohydrin (PAE), where PCA provides the catechol groups for strong adhesion, PAA serves as the primary polymer matrix, and PAE acts as a bridge connecting PCA and PAA. This design results in a PAA-PAE-PCA hydrogel having a remarkable instant 90-degree peeling interfacial toughness of 431 J m-2 on porcine skin, which is further amplified to 615 J m-2 after 30 minutes. The hydrogel also possesses the desired features for wound dressing, such as self-healing, antioxidant, anti-UV and antibacterial properties, good cytocompatibility, strong adhesion in use and weak adhesion on removal, as well as reversible and wet adhesion. Finally, in vivo data reveal that the PAA-PAE-PCA hydrogels can significantly accelerate wound healing, as evidenced by a noticeable reduction in the wound area and a diminished inflammatory response. Collectively, these results endorse the obtained multifunctional hydrogel as a promising candidate for wound healing and related fields.

Laccase-mediated coupling of nonpolar chains for the hydrophobization of lignocellulose.

We investigate the use of laccase enzymes to couple short nonpolar chains containing aromatic groups onto flax fibers and nanofibrillated cellulose (NFC) with different lignin contents. Trametes villosa , Pycnoporus cinnabarinus , and Myceliophthora thermophila were used to facilitate surface coupling and to produce materials with different levels of hydrophobicity. Heat treatment of fiber webs after lacccase-mediated coupling markedly increased the resistance to water absorption. The highest hydrophobization levels of flax fibers was achieved by coupling dodecyl 3,4,5-trihydroxybenzoate (HB-C12), which yielded water contact angles (WCAs) of 80-96 degrees and water absorption times (drop tests) of ca. 73 min. The results from apparent aromatic content and FTIR analyses confirmed the laccase-mediated coupling of HB-C12 onto the cellulose fibers. Ultrathin films of NFC were also used as substrates for enzyme-mediated hydrophobization with HB-C12. In these cases, WCAs in the range of 87-104 degrees were achieved, depending on the conditions. Quartz crystal microgravimetry (QCM) was used to study the dynamics and the extent of the coupling process onto cellulose. The results help to better understand the mechanisms involved in laccase-mediated hydrophobization and provide a proof of a biotechnological platform for the development of value-added fiber products.

[Non-alkaloid chemical constituents from Coptis chinensis].

OBJECTIVE: To separate and identify chemical constituents from Coptis chinensis. METHOD: The compounds were separated and purified by various chromatographic techniques. Their structures were identified on the basis of their physicochemical properties using spectral techniques such as NMR and MS. RESULT: Thirteen compounds were separated from ethanol extracts of C. chinensis, including seven lignans, three simple phenylpropanoids, two flavones and one phenolic acid, and identified as erythro-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (1), threo-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (2), (+)-pinoresinol (3), (+)-medioresinol (4), (+)-lariciresinol (5), (+)-5'-methoxylariciresinol (6), (+)-isolariciresinol (7), chlorogenic acid (8), ferulic acid (9), Z-octadecyl caffeate (10), rhamnetin (11), wogonin (12), and vanillic acid (13). CONCLUSION: Compounds 1, 2, 4, 6, 10-13 were separated from the genus Coptis for the first time.

Molecularly imprinted polymer microspheres for solid-phase extraction of protocatechuic acid in Rhizoma homalomenae.

Molecularly imprinted polymers (MIPs) had been prepared by precipitation polymerization method using acrylamide as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, acetonitrile as the porogen solvent and protocatechuic acid (PA), one of phenolic acids, as the template molecule. The MIPs were characterized by scanning electron microscopy and Fourier transform infrared, and their performance relative to non-imprinted polymers was assessed by equilibrium binding experiments. Six structurally similar phenolic acids, including p-hydroxybenzoic acid, gallic acid, salicylic acid, syringic acid, vanillic acid, ferulic acid were selected to assess the selectivity and recognition capability of the MIPs. The MIPs were applied to extract PA from the traditional Chinese medicines as a solid-phase extraction sorbent. The resultant cartridge showed that the MIPs have a good extraction performance and were able to selectively extract almost 82% of PA from the extract of Rhizoma homalomenae. Thus, the proposed molecularly imprinted-solid phase extraction-high performance liquid chromatography method can be successfully used to extract and analyse PA in traditional Chinese medicines.