Formation of haloacetic acids from different organic precursors in swimming pool water during chlorination

Haloacetic acids (HAAs) were reported to be the most abundant category of DBPs in swimming pool water. In this study, the formation of HAAs from different organic precursors in swimming pool water, including UV filters, human body fluids, and natural organic matter (NOM), during chlorination was examined, and the effects of chlorine dose and halide concentrations on the formation of HAAs were evaluated. The results show that the total HAA yields from benzophenone-3 (BP-3) and Suwannee River humic acid (SRHA) were the highest among the nine organic precursors, and the yields of dichloroacetic acid and bromochloroacetic acid were higher than that of the other HAA species. In all the chlorinated samples of different organic precursors, longer chlorination time enhanced HAA formation. Both chlorine dose and bromide concentration significantly affected the formation of HAAs from BP-3 and SRHA during chlorination. With the increasing chlorine dose, the total HAA yields from SRHA and BP-3 significantly increased. Besides, the proportion of trihaloacetic acids (THAAs) rose while that of dihaloacetic acids (DHAAs) and monohaloacetic acids (MHAAs) declined with the increasing chlorine dose. With the increasing bromide concentration, HAA formation from SRHA increased while that of BP-3 decreased. The bromine incorporation factor (BIF) of the formed MHAAs, DHAAs and THAAs from SRHA and BP-3 both increased with the increasing bromide concentration in the following order: BIF_DHAAs > BIF_THAAs > BIF_MHAAs, indicating that bromine was easier to be incorporated into DHAAs rather than MHAAs or THAAs. Moreover, bromide promoted the formation of Br-HAAs.

Computational pipeline for estimation of small-molecule T1 relaxation times

Molecular imaging of biologic molecules and cellular processes is increasingly accessible through hyperpolarization of chemically-equivalent stable isotopes, most commonly ¹³C. However, many molecules are poor candidates for imaging due to their biophysical properties, particularly short spin-lattice relaxation times (T₁). The inability to consistently predict the T₁ from molecular structure, lack of experimental data for many biologically-relevant molecules and the high cost of developing probes can limit the development of hyperpolarized probes. We describe an in silico pipeline for modeling the estimated T₁ of molecules of interest in order to address this deficiency. Applying a hybrid approach that incorporates molecular dynamics as well as quantum mechanics, this pipeline estimated T₁ values that closely matched empirically determined values providing proof-of-principle that this approach may be used to facilitate MR probe development.

Phytochemical Profile and Biological Activity of Endemic Sideritis sipylea Boiss. in North Aegean Greek Islands

Sideritis sipylea Boiss. is an endemic plant of the Mediterranean basin that is distributed in the Greek islands of the North Aegean Sea, i.e., Lesvos, Chios, Samos, and Ikaria, and in the West and Middle peninsula of Turkey. It is considered an endangered species because of its uncontrolled collection from its original habitat. Although the antioxidant, anti-inflammatory and antimicrobial properties have been previously reported, the total chemical profile has not yet been explored. In this context, the chemical profiles of the water/methanol (HA), methanol (ME), and ethyl acetate (EtOAc) extracts were analyzed using ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-HRMS). In parallel, analysis by gas chromatography-mass spectrometry (GC-MS) was employed for the dichloromethane extract (DCM) as well as for the essential oil (EO) and the extract obtained by supercritical fluid extraction (SFE). Furthermore, the total phenolic content (TPC) along with the in vitro tyrosinase and elastase enzyme inhibitory activity of different extracts was evaluated, towards the discovery of new active agents for cosmetic formulations. These activities are in accordance with its well-known antioxidant and anti-inflammatory properties, confirming the importance of ethnopharmacological references for S. sipylea in Greece and Turkey.

Characterization of ethyl acetate and n-butanol extracts of Cymbopogon schoenanthus and Helianthemum lippii and their effect on the smooth muscle of the rat distal colon

ETHNOPHARMACOLOGY RELEVANCE

Cymbopogon schoenanthus (C. schoenanthus) and Helianthemum lippii (H. lippii) are Saharan species found in the South West of Algeria, in the region of Bechar. Both plants are used in traditional medicine to treat gastrointestinal disorders.

OBJECTIVE

The aim of our study was to characterize the composition of the ethyl acetate (EtOAc) and n-Butanol (n-BuOH) extracts of C. schoenanthus and H. lippii, and to elucidate and compare their effect on the reactivity of the rat distal colon.

MAIN METHODS

The plants were macerated in a hydroalcoholic solution. After concentration, the aqueous solutions of the residues were submitted to liquid-liquid extractions to obtain EtOAc and n-BuOH extracts. The phenolic and flavonoid content of the extracts was determined by high performance liquid chromatography coupled with mass spectrometry with a time of flight analyzer (HPLC-TOF/MS). The effect of the extracts was tested on the rat distal colon, namely on the basal tone and on KCl- and Ach-induced precontracted preparations.

RESULTS

HPLC-TOF/MS identified 32 phenols and flavonoids in the extracts. The four extracts relaxed the rat distal colon, the effect being noticed on the basal tone and on the KCl- and Ach-induced precontractions. The EtOAc and the n-BuOH extracts of H. lippii decreased the basal tone of the rat distal colon more markedly than the correspondent extracts of C. schoenanthus. Moreover, the n-BuOH extract of C. schoenanthus decreased the basal tone more markedly than the EtOAc extract of this plant but there was no difference between extracts of H. lippii. The EtOAc extracts of both C. schoenanthus and H. lippii totally reverted both the KCl- and the Ach-induced precontraction of the rat distal colon. However, the n-BuOH extracts of the two plants reverted the Ach-precontracted colon but not the colon that has been precontracted with KCl.

CONCLUSION

Extracts of H. lippii contain a higher level of phenols compared to the extracts of C. schoenanthus. All extracts of C. schoenanthus and H. lippii caused marked relaxation of the isolated rat distal colon, either when applied directly or when tested over KCl- and Ach-induced precontraction. These results give support to the use of C. shoenanthus and H. lippii in traditional medicine, namely for gastrointestinal diseases.

Scrophularia Tenuipes Coss and Durieu: Phytochemical Composition and Biological Activities

Scrophularia tenuipes is an Algerian-Tunisian endemic species, which has not been studied yet. Ethyl acetate (EA) and n-butanol (Bu) fractions obtained from Scrophularia tenuipes were investigated for their health benefit properties, in particular with respect to in vivo/in vitro anti-inflammatory and antioxidant activities, as well as their potential to inhibit key enzymes with impact in diabetes (α-glucosidase and α-amylase). The fractions had a distinct phytochemical composition, of which EA was richer in total phenolic compounds (225 mg GAE/g) and mostly composed of the phenylethanoid acetyl martynoside. Compared to EA, Bu had higher amounts of total flavonoids, and according to the result obtained from UHPLC-DAD-ESI-MSn analysis, harpagoside (iridoid) was its major phytochemical. EA fraction was quite promising with regard to the in vivo (at 200 mg/kg, po) anti-inflammatory effect (62% and 52% for carrageenan-induced rat paw edema and xylene-induced ear edema tests, respectively), while Bu fraction exhibited a stronger antioxidant capacity in all tests (IC50 = 68 µg/mL, IC50 = 18 µg/mL, IC50 = 18 µg/mL and A0.50 = 43 µg/mL for DPPH●, ABTS•+, O2•- scavenging assays and cupric-reducing antioxidant capacity method, respectively). Both fractions also showed a strong effect against α-amylase enzyme (IC50 = 8 µg/mL and 10 µg/mL for EA and Bu fraction, respectively).

Antioxidant, anti-inflammatory and healing potential of ethyl acetate fraction of Bauhinia ungulata L. (Fabaceae) on in vitro and in vivo wound model

The present work aimed to investigate the antioxidant, anti-inflammatory and wound healing potential of ethyl acetate fraction from Bauhinia ungulata L. (FABU) on in vitro and in vivo models. Wound healing assay using human lung adenocarcinoma A549 cell line was employed to evaluate the ability of FABU in modulating cell migration. In addition, a surgical wound model in C57BL/6 mice was used to study the healing potential of FABU incorporated into gel carbomer 940 (Carbopol®). Evaluation of lipid peroxidation, inflammatory and anti-inflammatory mediator gene expression, rate of wound closure, and histological analysis were done. FABU significantly reduced the gap area in in vitro wound healing assay, 24 h after treatment. In the animal model, FABU at 0.5% topically applied once-daily for 5 days to the surgical wounds significantly reduced the lesion area. Moreover, it significantly decreased the levels of lipid peroxidation in the lesions and decreased the relative gene expression levels of IL-1β and TNF-α in the injured region. In conclusion, our study suggests that Bauhinia ungulata can effectively promote the wound healing, probably by regulating the inflammatory environment during the early stages of the process.

Hypromellose acetate succinate based amorphous solid dispersions via hot melt extrusion: Effect of drug physicochemical properties

In this study, the impact of drug and hydroxypropyl methylcellulose acetate succinate (HPMCAS) grades physicochemical properties on extrusion process, dissolution and stability of the hot melt extruded amorphous solid dispersions (ASDs) of nifedipine and efavirenz was investigated. Incorporation of drugs affected the extrusion temperature required for solid dispersion preparation. Differential scanning calorimetry and powder X-ray diffraction studies confirmed the amorphous conversion of the drugs in the prepared formulations. The amorphous nature of ASDs was unchanged after 3 months of stability testing at 40 °C and 75% relative humidity. The dissolution efficiency of the ASDs was dependent on the log P of the drug. The inhibitory effect of HPMCAS on drug precipitation was dependent on the hydrophobic interactions between drug and polymer, polymer grade, and dose of the drug. The dissolution efficiency and dissolution rate of the ASDs were dependent on the log P of the drug and solubility and hydrophilicity of the polymer grade respectively. The inhibitory effect of HPMCAS on drug precipitation was dependent on the hydrophobic interactions between drug and polymer, polymer grade, and the dissolution dose of the drug.

Use of Index-Based Screening Models to Evaluate the Leaching of Triclopyr and Fluroxypyr Through a Loam Soil Amended with Vermicompost

The effect of vermicompost added to a loam soil on the leaching behaviour of two herbicides (triclopyr and fluroxypyr) was examined. Mobility of the herbicides was assessed using disturbed soil columns under laboratory conditions. In both cases, the addition of vermicompost significantly increased the sorption of the compounds. For both, DT₅₀ values were slightly higher in the amended soil, due to the increased adsorption. Rate constants (k) calculated according to pseudo-first order model were significantly lower in the case of triclopyr (very persistent), which led to a much lower degradation rate compared to fluroxypyr (persistent) in both unamended and amended soils. Values calculated for the experimental leaching index (ELI) in unamended and amended soils showed medium and high leachability for fluroxypyr (0.31 and 0.29) and triclopyr (0.72 and 0.70), respectively. Other index-based screening models (GUS, RLPI, LIX) also catalogue both herbicides as potential leachers. Results confirm that triclopyr and fluroxypyr may contaminate groundwater resources.

Benefit of Later-Time-Point PET Imaging of HER3 Expression Using Optimized Radiocobalt-Labeled Affibody Molecules

HER3-binding affibody molecules are a promising format for visualization of HER3 expression. Cobalt-55, a positron-emitting isotope, with a half-life of 17.5 h, allows for next-day imaging. We investigated the influence of the charge of the radiocobalt–chelator complex on the biodistribution of anti-HER3 affibody molecule (HE)₃-Z_HER3 and compared the best radiocobalt-labeled variant with a recently optimized gallium-labeled variant. Affibody conjugates (HE)₃-Z_HER3-X (X = NOTA, NODAGA, DOTA, DOTAGA) were labeled with [⁵⁷Co]Co (surrogate for ⁵⁵Co). Affinity measurements, binding specificity and cellular processing were studied in two HER3-expressing cancer cell lines. Biodistribution was studied 3 and 24 h post-injection (pi) in mice with HER3-expressing BxPC-3 xenografts and compared to [⁶⁸Ga]Ga-(HE)₃-Z_HER3-NODAGA. Micro-single-photon emission tomography/computed tomography (microSPECT/CT) and micro-positron emission tomography/computed tomography (microPET/CT) imaging was performed 3 and 24 h pi. Stably labeled conjugates bound to HER3 with subnanomolar affinity. [⁵⁷Co]Co-(HE)₃-Z_HER3-DOTA had the best tumor retention and a significantly lower concentration in blood than other conjugates, leading to superior tumor-to-blood and tumor-to-liver ratios 24 h pi. Compared to [⁶⁸Ga]Ga-(HE)₃-Z_HER3-NODAGA 3 h pi, [⁵⁷Co]Co-(HE)₃-Z_HER3-DOTA provided superior imaging contrast in liver 24 h pi. Concluding, the composition and charge of the [⁵⁷Co]Co–chelator complex influenced the uptake in tumors and normal tissue. [⁵⁷Co]Co-(HE)₃-Z_HER3-DOTA provided the best imaging properties among the cobalt-labeled conjugates. Delayed imaging of HER3 expression with [⁵⁷Co]Co-(HE)₃-Z_HER3-DOTA improved imaging contrast compared to early-time-point imaging with [⁶⁸Ga]Ga-(HE)₃-Z_HER3-NODAGA.

Native Mass Spectrometry of Protein and DNA Complexes Prepared in Nonvolatile Buffers

Inorganic salts and nonvolatile-buffer components affect the structure and stability of proteins, and some protein complexes are unable to maintain their function and structure without them. However, it is well-known that these components cause suppression of analyte ionization during the electrospray ionization process. Thus, to establish appropriate methods for observation of the intact ions of protein and DNA complexes by native mass spectrometry (native MS) in the presence of nonvolatile buffer components, we herein examined the effect of ammonium acetate addition to a model homotetramer protein, alcohol dehydrogenase (ADH), which was prepared in a range of nonvolatile buffers, including Tris-HCl, phosphate, and HEPES buffers. Furthermore, native MS of nucleosome core particle (NCP), a large protein-DNA complex, prepared in nonvolatile buffer, was also examined. Intact ADH and NCP ions could be observed upon the addition of ammonium acetate, but NCP does not require as high of a concentration of ammonium acetate as ADH. Well-resolved peaks with different charge numbers could be observed for NCP prepared in Tris-HCl by addition of a lower amount of ammonium acetate than for ADH. This suggests that the effects of additives on native MS of biomolecular complexes can vary depending on the intramolecular interactions present. More specifically, NCP is stabilized mainly by electrostatic interactions, whereas the ADH tetramer depends on the presence of hydrophobic interactions between the four subunits. The results presented herein therefore are expected to contribute to structural biology studies of unstable protein-DNA complexes that are formed transiently during the transcription process.

Characterization of Ethyl Acetate and Trichloromethane Extracts from Phoebe zhennan Wood Residues and Application on the Preparation of UV Shielding Films

In this work, ethyl acetate (EA) and trichloromethane (TR) extracts were extracted from Phoebezhennan wood residues and the extracts were then applied to the preparation of UV shielding films (UV-SF). The results revealed that substances including olefins, phenols and alcohols were found in both EA and TR extracts, accounting for about 45% of all the detected substances. The two extracts had similar thermal stability and both had strong UV shielding ability. When the relative percentage of the extract is 1 wt% in solution, the extract solution almost blocked 100% of the UV-B (280–315 nm), and UV-A (315–400 nm). Two kinds of UV-SF were successfully prepared by adding the two extracts into polylactic acid (PLA) matrix. The UV-SF with the addition of 24 wt% of the extractive blocked 100% of the UV-B (280–315 nm) and more than 80% of the UV-A (315–400 nm). Moreover, the UV shielding performance of the UV-SF was still stable even after strong UV irradiation. Though the addition of extracts could somewhat decrease the thermal stability of the film, its effect on the end-use of the film was ignorable. EA extracts had less effect on the tensile properties of the films than TR extracts as the content of the extract reached 18%. The results of this study could provide fundamental information on the potential utilization of the extracts from Phoebe zhennan wood residues on the preparation of biobased UV shielding materials.

Ethyl acetate extract of Caesalpinia sappan L. inhibited acute myeloid leukemia via ROS-mediated apoptosis and differentiation

BACKGROUND

The dried heartwood of Caesalpinia sappan L. is traditionally prescribed in the formula of traditional Chinese medicine (TCM) for the treatment of acute myeloid leukemia (AML), while nothing is yet known of the active fractions and the underlying mechanisms.

PURPOSE

This study aims to investigate the effect of the ethyl acetate extract of the dried heartwood of Caesalpinia sappan L. (C-A-E) on induction of apoptosis and promotion of differentiation in vitro and anti-AML activity in vivo.

STUDY DESIGN/METHODS

The aqueous extract was sequentially separated with solvents of increasing polarity and the active fraction was determined through the inhibition potency. The inhibition of the active fraction on cell viability, proliferation and colony formation was performed in different AML cells. Induction of apoptosis and the promotion of differentiation were further determined. Then, the level of the reactive oxygen species (ROS) and its potential role were assessed. Finally, anti-AML activity was evaluated in NOD/SCID mice.

RESULTS

C-A-E exhibited the highest inhibition on the cell viability of HL-60 cells. Meanwhile, C-A-E significantly suppressed the proliferation and the colony formation ability of HL-60 and Kasumi-1 cells. Moreover, C-A-E significantly induced the apoptosis, which was partially reversed by Z-VAD-FMK. C-A-E also reduced the level of mitochondrial membrane potential, promoted the release of cytochrome C, decreased the Bcl-2/Bax ratio, and promoted the cleavage of caspase-9 and -3. In addition, Mdivi-1 (mitochondrial fission blocker) remarkably reduced the apoptosis caused by C-A-E. Meanwhile, C-A-E also induced the expression of Mff and Fis1 and increased the location of Drp1 in mitochondria. Furthermore, C-A-E obviously promoted the differentiation of AML cells characterized by the typic morphological changes, the increased NBT positive cells, as well as the increased CD11b and CD14 levels. Notably, C-A-E significantly enhanced the intracellular ROS level. Moreimportantly, C-A-E-mediated apoptosis and differentiation of HL-60 cells was significantly mitigated by NAC. Additionally, C-A-E also exhibited an obvious anti-AML effect in NOD/SCID mice with the injection of HL-60 cells.

CONCLUSIONS

C-A-E exhibited an inhibitory effect on AML cells by inducing mitochondrial apoptosis and promoting differentiation, both of which were highly correlated to the activation of ROS.

Carboxymethyl-kappa-carrageenan: A study of biocompatibility, antioxidant and antibacterial activities

Chemical modification of polysaccharides is an important route to enhance, develop or change polysaccharide properties. In this study, carboxymethylation of kappa-carrageenan (KC) with monochloroacetic acid was performed to achieve different degrees of substitution (DS) of carboxymethyl-kappa-carrageenan (CMKC). The degree of substitution ranged from 0.8 to 1.6 and was calculated from the ¹H NMR spectra. The chemical structure of the CMKCs was further characterized by FT-IR, and ¹³C NMR. FT-IR confirmed the carboxymethylation. Carboxymethylation increased viscosity of KC in water and decreased viscosity of KC in synthetic human sweat. Tests with human adipose derived stem cells showed higher viability and lower cytotoxicity for CMKCs when compared to KC. CMKCs showed no hemolytic activity to human red blood cells. CMKCs have increased antioxidant activity compared to KC. In antibacterial assays, CMKCs with DS of 0.8, 1.0 and 1.2 exhibited growth inhibition against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. CMKC with DS ranging from 1.0 to 1.2 are good candidate biomaterials for cell-contacting applications.

Biomimetic Oxidation of Monolignol Acetate and p-Coumarate by Silver Oxide in 1,4-Dioxane

Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of γ-acylated monolignols with Ag₂O was studied to understand the effect of γ-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave γ-acylated and α-acylated β-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced γ-acylated β-O-4 and γ-acylated tetralin β-β dimers in 53 and 16% yields, respectively. Only the sinapyl alcohol moiety in sinapyl p-coumarate reacted, and the p-coumarate moiety remained unchanged, suggesting that p-coumaric acid is not incorporated into the lignin backbone in the acylated lignins. All of the γ-acylated monolignols used in this study produced the γ-acylated β-O-4 dimers, which suggests that the γ-acylated monolignols act as lignin monomers. The relatively high yields of the β-O-4 dimers indicate that Ag₂O oxidation of the monolignols can be used as an easy method for synthesizing the β-O-4 dimer model compounds.

Antioxidant Activity of Pastinaca sativa L. ssp. sylvestris [Mill.] Rouy and Camus Essential Oil

In the last decade, there has been growing interest in the food industry in replacing synthetic chemicals with natural products with bioactive properties. This study's aims were to determine the chemical composition and the antioxidant properties of the essential oil of Pastianica sylvestris. The essential oil was isolated with a yield of 0.41% (w/v) by steam distillation from the dried seeds and subsequently analysed by GC-MS. Octyl acetate (78.49%) and octyl hexanoate (6.68%) were the main components. The essential oil exhibited an excellent activity for the inhibition of primary and secondary oxidation products for cold-pressed sunflower oil comparable with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), which were evaluated using peroxide and thiobarbituric acid values. The antioxidant activity of the essential oil was additionally validated using DPPH radical scavenging (0.0016 ± 0.0885 mg/mL), and β-carotene-linoleic acid bleaching assays. Also, the amounts of total phenol components (0.0053 ± 0.0023 mg GAE/g) were determined.

Aqueous ethyl acetate as a novel solvent for the degreasing of black soldier fly (Hermetia illucens L.) larvae: degreasing rate, nutritional value evaluation of the degreased meal, and thermal properties

BACKGROUND

The aim of this study was to select appropriate low-toxicity degreasing solvents to degrease black soldier fly (BSF, Hermetia illucens L.) larvae to prepare high-quality protein. Aqueous ethyl acetate was chosen as the solvent to extract BSF protein, and traditional solvents, such as petroleum ether, n-hexane, and isopropanol, were chosen as controls.

RESULTS

The meal degreased by aqueous ethyl acetate (the volume ratio of ethyl acetate to water is 90 to 10, EA + W10) shows a high degreasing rate (29.04%), crude protein content (562.3 g kg^-1 ), essential amino acid index (EAAI, 95.57), and digestible indispensable amino acid score (DIAAS, 85). The digestibility of the degreased meal samples in the simulated in vitro intestine can reach 76.52%. Thermodynamic analysis and the apparent morphology of the protein fragments showed that the meal degreased by EA + W10 exhibited thermodynamic stability, which suggests that using aqueous ethyl acetate as the degreasing solvent did not affect the nutritional value of the degreased meal.

CONCLUSION

The results suggest that aqueous ethyl acetate (EA + W10) can be used as a novel solvent in the degreasing of BSF larvae meal to prepare high-quality protein with high EAAI and DIAAS and good digestibility. © 2019 Society of Chemical Industry.

In vitro toxicity and molecular interacting mechanisms of chloroacetic acid to catalase

Chloroacetic acid (CAA), one of typical disinfection by-products (DBPs), has attracted considerable concerns for its biological safety. Antioxidant enzyme catalase (CAT) plays a crucial part in the regulation of redox state balance. Herein, CAA was used to test its adverse effects on CAT and explore the underlying mechanism. The cell viability of mouse primary hepatocytes decreased under CAA exposure. A bell-shaped response to CAA exposure was observed in intracellular CAT activity, whose change was partly influenced by molecular CAT activity. CAA binds to CAT mainly via van der Waals forces and hydrogen bonds with a stoichiometry of 9.2. The binding caused structural changes in CAT with the unfolding of polypeptide chains and the decrease of α-helical content. CAA interacts with the amino acid residues surrounding the active sites and substrate channel of CAT. These interactions result in the decrease of molecular CAT activity, which could be restored by high ionic strength. This study has provided a combined molecular and cellular tactics for studying the adverse effects of DBPs on biomarkers and the underlying mechanisms.

In vivo preclinical evaluation of the new 68Ga-labeled beta-cyclodextrin in prostaglandin E2 (PGE2) positive tumor model using positron emission tomography

The cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway plays an important role in tumor development and formation of metastases. It was earlier reported that cyclodextrin derivatives have a high affinity to form complexes with PGE2. Based on these results radiolabeled cyclodextrins - as new radiopharmaceuticals - may open a new pathway in the in vivo imaging and diagnosis of PGE2 positive tumors. The aims of this study were to synthetize the PGE2 specific ⁶⁸Ga-labeled NODAGA-randomly methylated beta-cyclodextrin (⁶⁸Ga-NODAGA-RAMEB) and investigate its tumor-targeting properties. NODAGA-RAMEB was labeled with Gallium-68 (⁶⁸Ga), and the radiochemical purity (RCP%), partition coefficient (logP values), and in vitro-in vivo stability of ⁶⁸Ga-NODAGA-RAMEB were determined. After intravenous injection of ⁶⁸Ga-NODAGA-RAMEB the accumulation in organs and tissues was monitored in vivo by positron emission tomography (PET) and ex vivo by gamma counter in BxPC-3 and PancTu-1 tumor-bearing CB17 SCID mice. The RCP% of the newly synthesized ⁶⁸Ga-NODAGA-RAMEB was higher than 98%. The molar activity was 15.34 ± 1.93 GBq/μmol. The logP of ⁶⁸Ga labeled NODAGA-RAMEB was - 3.63 ± 0.04. Biodistribution studies showed high accumulation of ⁶⁸Ga-NODAGA-RAMEB in PGE2 positive BxPC-3 tumors; approximately 15-20-fold higher radiotracer uptake was observed, than that of the background. ⁶⁸Ga-labeled RAMEB is a promising radiotracer in PET diagnostics of PGE2 positive tumors.

Quality Control of Psoralea corylifolia L. Based on High-Speed Countercurrent Chromatographic Fingerprinting

Traditional Chinese medicine (TCM)has played an important role in promoting the health of Chinese people. The TCM Psoralea corylifolia L. has been used in the treatment of various kinds of diseases including enuresis, vitiligo, and calvities. However, therapeutic effects of P. corylifolia L. have often influenced by the quality of plants. So, it is very important to control the quality of P. corylifolia L. In this study, analytical high-speed countercurrent chromatography (HSCCC) was successfully used to fingerprint P. corylifolia L. Samples of P. corylifolia L. were extracted by ultrasonic extraction. n-hexane-ethyl acetate–methanol–water at a ratio of 5:5.5:6.5:5 (v/v) was selected as a two-phase solvent system and the condition of HSCCC were optimized in order to good separation. And the method of HSCCC was verified (reproducibility, precision, and stability). HSCCC chromatograms exhibited six common peaks, which were selected as indicator compounds for the quality control of P. corylifolia L. Within 20 types of medicinal materials, chemical components are similar, but the levels of components are quite different in HSCCC fingerprint. The present results demonstrate that the HSCCC method provides a reliable basis for the quality control of P. corylifolia L. and can also be applied to confirm the authenticity of plant materials.

Pulse-Programmable Magnetic Field Sweeping of Parahydrogen-Induced Polarization by Side Arm Hydrogenation

Among the hyperpolarization techniques geared toward in vivo magnetic resonance imaging, parahydrogen-induced polarization (PHIP) shows promise due to its low cost and fast speed of contrast agent preparation. The synthesis of 13C-labeled, unsaturated precursors to perform PHIP by side arm hydrogenation has recently opened new possibilities for metabolic imaging owing to the biological compatibility of the reaction products, although the polarization transfer between the parahydrogen-derived protons and the 13C heteronucleus must yet be better understood, characterized, and eventually optimized. In this realm, a new experimental strategy incorporating pulse-programmable magnetic field sweeping and in situ detection has been developed. The approach is evaluated by measuring the 13C polarization of ethyl acetate-1-13C, i.e., the product of pairwise addition of parahydrogen to vinyl acetate-1-13C, resulting from zero-crossing magnetic field ramps of various durations, amplitudes, and step sizes. The results demonstrate (i) the profound effect these parameters have on the 1H to 13C polarization transfer efficiency and (ii) the high reproducibility of the technique.

Instant Thermal Switching from Soft Hydrogel to Rigid Plastics Inspired by Thermophile Proteins

Proteins of thermophiles are thermally stable in a high-temperature environment, adopting a strategy of enhancing the electrostatic interaction in hydrophobic media at high temperature. Herein, inspired by the molecular mechanism of thermally stable proteins, the synthesis of novel polymer materials that undergo ultrarapid, isochoric, and reversible switching from soft hydrogels to rigid plastics at elevated temperature is reported. The materials are developed from versatile, inexpensive, and nontoxic poly(acrylic acid) hydrogels containing calcium acetate. By the cooperative effects of hydrophobic interaction and ionic interaction, the hydrogels undergo significant spinodal decomposition and subsequent rubbery-to-glassy transition when heated to an elevated temperature. As a result, the gels exhibit super-rapid and significant hikes in stiffness, strength, and toughness by up to 1800-, 80-, and 20-folds, respectively, when the temperature is raised from 25 to 70 °C, while the volumes of the gels are almost unchanged. As a potential application, the performance of the materials as athletic protective gear is demonstrated. This work provides a pathway for developing thermally stiffened materials and may significantly broaden the scope of polymer applications.

Complete dehalogenation of bromochloroacetic acid by liquid phase catalytic hydrogenation over Pd/CeO2 catalysts

Bromochloroacetic acid is classified as one of the typical disinfection byproducts (DBPs). In this work, supported palladium catalysts on different supports (CeO_2, Al₂O₃, SiO₂ and activated carbon (AC)) (labelled as Pd/support) were synthesized via the deposition-precipitation method (D-P method) and their activities for the complete dehalogenation of bromochloroacetic acid by liquid phase catalytic hydrogenation were evaluated. Comprehensive characterizations of the catalysts were conducted by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), point of zero charge (PZC), X-ray photoelectron spectroscopy (XPS) and CO chemisorption. Results indicated that the PZCs of the supports varied with each other. The stronger Pd-support interaction and higher Pd dispersion of Pd/CeO₂ and Pd/Al₂O₃ than those of Pd/AC and Pd/SiO₂ were confirmed by X-ray photoelectron spectroscopy and CO chemisorption. Pd/CeO₂ had a higher ratio of positively charged Pd to metallic Pd (Pdⁿ⁺/Pd⁰) than Pd/Al₂O₃ and Pd/AC due to a stronger metal-support interaction. Accordingly, a negligible bromochloroacetic acid conversion was observed on Pd/SiO₂, whereas bromochloroacetic acid was found to be readily decomposed on Pd/CeO₂, Pd/Al₂O₃ and Pd/AC. However, the dechlorination reaction could not further proceed on Pd/Al₂O₃ and Pd/AC catalysts after the bromine functionality was removed from bromochloroacetic acid. A complete dehalogenation of bromochloroacetic acid occurred only on Pd/CeO₂. Furthermore, the dechlorination rate constants of monochloroacetic acid and bromochloroacetic acid over Pd(1.40)/CeO₂ were 0.018 and 0.031 min^-1 respectively, confirming an induced synergistic effect due to the existence of bromine atoms. It was worth noting that a stepwise-concerted pathway was verified during the liquid phase catalytic hydrodehalogenation of bromochloroacetic acid.

Enantioselective Iridium-Catalyzed Allylation of Acetylenic Ketones via 2-Propanol-Mediated Reductive Coupling of Allyl Acetate: C14-C23 of Pladienolide D

Highly enantioselective catalytic reductive coupling of allyl acetate with acetylenic ketones occurs in a chemoselective manner in the presence of aliphatic or aromatic ketones. This method was used to construct C14-C23 of pladienolide D in half the steps previously required.

Evaluating Iso-Mukaadial Acetate and Ursolic Acid Acetate as Plasmodium falciparum Hypoxanthine-Guanine-Xanthine Phosphoribosyltransferase Inhibitors

To date, Plasmodium falciparum is one of the most lethal strains of the malaria parasite. P. falciparum lacks the required enzymes to create its own purines via the de novo pathway, thereby making Plasmodium falciparum hypoxanthine-guanine-xanthine phosphoribosyltransferase (PfHGXPT) a crucial enzyme in the malaria life cycle. Recently, studies have described iso-mukaadial acetate and ursolic acid acetate as promising antimalarials. However, the mode of action is still unknown, thus, the current study sought to investigate the selective inhibitory and binding actions of iso-mukaadial acetate and ursolic acid acetate against recombinant PfHGXPT using in-silico and experimental approaches. Recombinant PfHGXPT protein was expressed using E. coli BL21 cells and homogeneously purified by affinity chromatography. Experimentally, iso-mukaadial acetate and ursolic acid acetate, respectively, demonstrated direct inhibitory activity towards PfHGXPT in a dose-dependent manner. The binding affinity of iso-mukaadial acetate and ursolic acid acetate on the PfHGXPT dissociation constant (KD), where it was found that 0.0833 µM and 2.8396 µM, respectively, are indicative of strong binding. The mode of action for the observed antimalarial activity was further established by a molecular docking study. The molecular docking and dynamics simulations show specific interactions and high affinity within the binding pocket of Plasmodium falciparum and human hypoxanthine-guanine phosphoribosyl transferases. The predicted in silico absorption, distribution, metabolism and excretion/toxicity (ADME/T) properties predicted that the iso-mukaadial acetate ligand may follow the criteria for orally active drugs. The theoretical calculation derived from ADME, molecular docking and dynamics provide in-depth information into the structural basis, specific bonding and non-bonding interactions governing the inhibition of malarial. Taken together, these findings provide a basis for the recommendation of iso-mukaadial acetate and ursolic acid acetate as high-affinity ligands and drug candidates against PfHGXPT.

Further isolation and identification of anti-diabetic principles from root bark of Myrianthus arboreus P. Beauv.: The ethyl acetate fraction contains bioactive phenolic compounds that improve liver cell glucose homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

We recently reported that ethanol extract of Myrianthus arboreus P. Beauv. root bark demonstrated antidiabetic activity by modulating hepatocyte glucose homeostasis. This activity was associated significantly to the ethyl acetate (EAc) fraction. The current study sought to identify the active compounds responsible of the antidiabetic effect of M. arboreus in the EAc fraction using bioassay-directed sub-fractionation.

MATERIALS AND METHODS

EAc fraction was sub-fractionated using Flash chromatography. Preparative HPLC was used to isolate the pure compounds. The structures of the isolated compounds were confirmed by analysis of NMR spectroscopic and mass spectrometric data. Hepatic (H4IIE, HepG2) cells were treated with maximum non-toxic concentrations of ethanol extract, its EAc fraction and isolated compounds thereof. Glucose-6-phosphatase (G6Pase) activity was measured using the glucose oxidase method. To measure glycogen synthase (GS) activity, radioactive assays were used. Phosphorylation of AMP-activated protein kinase (AMPK) and Glycogen Synthase Kinase-3 (GSK-3) were probed by Western blot.

RESULTS

Six sub-fractions were obtained, and the antidiabetic activity was found in two sub-fractions (SFE1 and SFE2). For the first time, two known C-glycosylflavone regio-isomers, isoorientin (1) and orientin (2) were detected and isolated from M. arboreus plant, especially from SFE2 as well as protocatechuic acid, 3,4-dihydroxybenzaldehyde (4), and chlorogenic acid isolated from SFE1. The compounds 1, 2, 4 were determined to decrease the activity of G6Pase by increasing AMPK phosphorylation and to stimulate GS through GSK-3 phosphorylation. Isoorientin which is one of the main compounds of EAc fraction, expressed the strongest effect in all bioassays, similar to that of the EAc fraction. A significant and linear correlation was found between the phosphorylation of AMPK and the activity of G6Pase modulated by all samples (R² = 0.54; p < 0.05). Similar to G6Pase assay, a correlation was determined between the capacity of M. arboreus extracts/fractions/compounds to stimulate GS activity and to phosphorylate GSK-3 (R² = 0.57, p < 0.01).

CONCLUSION

Results demonstrate that 1, 2, 4 are responsible, at least in part, for the antidiabetic activity of M. arboreus. These compounds can be used to ensure the quality and efficacy of M. arboreus antidiabetic preparations and standardize such preparations.