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Perfluorinated and polyfluoroalkyl substances (PFASs) are known for their long-distance migration, bioaccumulation, and toxicity. The transport of PFASs in the environment has been a source of increasing concerned. The organic carbon normalized sorption coefficient (Koc) is an important parameter from which to understand the distribution behavior of organic matter between solid and liquid phases. Currently, the theoretical prediction research on log Koc of PFASs is extremely limited. The existing models have limitations such as restricted application fields and unsatisfactory prediction results for some substances. In this study, a quantitative structure–property relationship (QSPR) model was established to predict the log Koc of PFASs, and the potential mechanism affecting the distribution of PFASs between two phases from the perspective of molecular structure was analyzed. The developed model had sufficient goodness of fit and robustness, satisfying the model application requirements. The molecular weight (MW) related to the hydrophobicity of the compound; lowest unoccupied molecular orbital energy (ELUMO) and maximum average local ionization energy on the molecular surface (ALIEmax), both related to electrostatic properties; and the dipole moment (μ), related to the polarity of the compound; are the key structural variables that affect the distribution behavior of PFASs. This study carried out a standardized modeling process, and the model dataset covered a comprehensive variety of PFASs. The model can be used to predict the log Koc of conventional and emerging PFASs effectively, filling the data gap of the log Koc of uncommon PFASs. The explanation of the mechanism of the model has proven to be of great value for understanding the distribution behavior and migration trends of PFASs between sediment/soil and water, and for estimating the potential environmental risks generated by PFASs.

A drug–drug multicomponent crystal consisting of metformin (MET) and dobesilate (DBS) was prospectively connected by solvent cooling and evaporating co-crystallization using the multicomponent crystal strategy, not only to optimize the physicochemical properties of single drugs, but also to play a role in the cooperative effect of DBS with the potential vascular protective effects of MET against diabetic retinopathy (DR). The crystal structure analysis demonstrated that MET and DBS were coupled in a 3D supramolecular structure connected by hydrogen-bonding interactions with a molar ratio of 1:1. Almost all hydrogen bond donors and receptors of MET and DBS participated in the bonding, which hindered the combination of remaining potential hydrogen bond sites and water molecules, resulting in a lower hygroscopicity property than MET alone.

In the present study, we confirmed that α-asaronol, which is a product of the active metabolites of alpha Asarone, did not affect n-butylphthalide efficacy when n-butylphthalide and α-asaronol were co-administered to rats with cerebral ischemia-reperfusion injury. Our research revealed that the co-administration of α-asaronol and n-butylphthalide could further improve neurological function, reduce brain infarct volume, increase the number of Nissl bodies, and decrease the ratios of apoptotic cells and the expression of the caspase-3 protein for cerebral ischemia-reperfusion injury model compared to n-butylphthalide alone. Additionally, α-asaronol could significantly decrease the incidence of post-stroke epilepsy versus n-butylphthalide. This study provides valuable data for the follow-up prodrug research of α-asaronol and n-butylphthalide.

The formation of most multicomponent crystals relies on the interaction of hydrogen bonds between the components, so rational crystal design based on the expected hydrogen-bonded supramolecular synthons was employed to establish supramolecular compounds with desirable properties. This theory was put into practice for metformin to participate in more therapeutic fields to search for a fast and simple approach for the screening of candidate crystal co-formers. The prediction of intermolecular synthons facilitated the successful synthesis of a new multicomponent crystal of metformin (Met) and barbital (Bar) through an anion exchange reaction and cooling crystallization method. The single crystal X-ray diffraction analysis demonstrated the hydrogen bond-based ureide/ureide and guanidine/ureide synthons were responsible for the self-assembly of the primary structural motif and extended into infinite supramolecular heterocatemeric structures.

A co-crystal of rosiglitazone (Rsg) with berberine (Bbr), Rsg-Bbr, was prepared by the solvent evaporation method and characterized. The results showed that the electrostatic attraction existed between the nitrogen anion of rosiglitazone and the quaternary ammonium cation of berberine, and C-H···O hydrogen bonds were formed between Rsg and Bbr. In the crystal structure, rosiglitazone molecules stack into a supramolecular layer through π-π interactions while π-π interactions between berberine cations also result in a similar layer. The co-crystal presented a low moisture adsorption curve in the range of 0−95% relative humidity values at 25 °C. The improved dissolution rate of rosiglitazone in pH = 6.8 buffer solution could be achieved after forming co-crystal.

Both rosiglitazone and metformin have effects on blood glucose regulation and the proliferation of liver cancer cells. Combination therapy with these two drugs is common and effective for the treatment of diabetes in the clinic, however, the application of these two drugs is influenced by the poor dissolution of rosiglitazone and the gastrointestinal side-effect of metformin resulting from a high solubility. The formation of a multidrug crystal form (Rsg-Met) by a solvent evaporation method can solve the solubility issue. Crystal structure data and intramolecular hydrogen bonds were detected by X-ray diffraction and infrared spectroscopy. Surprisingly, Rsg-Met shortens the time spent in solubility equilibrium and multiplies the dissolution rate of Rsg. Finally, we found that a low concentration of Rsg-Met enhanced the proliferation inhibition effect on liver cancer cells (HepG2, SK-hep1) compared with rosiglitazone, without affecting the human normal cell line LO2.

A multidrug crystal based on drug combinations was synthesized by the solvent evaporation method. This multicomponent crystal consisted of antidiabetic drugs Glimepiride (Gli) and Metformin (Met), which was performed by single crystal X-ray structure analysis. The results showed an enhancement of the pharmaceutical properties such as lower hygroscopicity and greater accelerated stability than the parent drug Met, and a higher solubility and dissolution rate than Gli.

A copper-catalyzed domino reaction between itaconate esters and diethyl zinc (or silane) is developed, affording itaconate dimerization products, multi-ester-substituted cyclopentanones, in moderate to high yields.

Phytochemical investigations of ethyl acetate-soluble part of the aerial part of Hypericum scabrum L. delivered eight pure phenolic compounds 1–8. The pure compounds were identified through physico-chemical, NMR (1D, 2D) and mass spectrometric studies as: 3-8′′-bisapigenin (1), quercetin (2), quercetin-3-O-α-l-arabinofuranoside (3), quercetin-3-O-α-l-rhamnoside (4), quercetin-3-O-β-d-glucopyranoside (5), quercetin-3-O-β-d-galactopyranoside (6), (−)-epicatechin (7), (+)-catechin (8). Total polyphenolic compounds and total flavonoids contents were determined in the extract as 0.107 mg∙mg−1 and 0.023 mg∙mg−1 of the dried extract, respectively. Antioxidant activity using DPPH free radical scavenging assay delivered very strong activity for compounds 2 and 5, 6 and crude extract 10. Protein tyrosine phosphatase 1B (PTP-1B) inhibition experiment of isolated compounds and crude extracts resulted in significant inhibition activity for samples 2, 7a, 8a, 11 and 12 with IC50 values ranging from 1.57 to 2.91 µM. Antimicrobial activity of the pure compounds and extracts produced average results against Staphylococcus aureus, Escherichia coli and Candida albicans strains. From our literature survey, it appears that all pure compounds except 2 were isolated and reported for the first time in H. scabrum.

Suzuki-Miyaura coupling reactions are promoted by Pd complexes ligated with C2-symmetric multi-dentate N-heterocyclic carbenes derived in situ from Pd(OAc)2 and imidazolium salts. Good to excellent yields were obtained for aryl bromides as substrates. Turnover numbers of up to 105 could be achieved with 5 × 10−4 mol% of Pd(OAc)2/1 × 10−3 mol% NHC precatalyst in 24 h.

The purpose of this study was to investigate the chemical composition and biological activity of the volatile oils (VOs) from the flowers of three buckwheat species, Fagopyrum esculentum, Fagopyrum tataricum and Fagopyrum cymosum. The VOs were obtained from the fresh buckwheat flowers by hydrodistillation, and were analyzed for their chemical composition by gas chromatography-mass spectrometry (GC-MS). Nonanoic acid (7.58%), (E)-3-hexen-1-ol (6.52%), and benzothiazole (5.08%) were the major constituents among the 28 identified components which accounted for 92.89% of the total oil of F. esculentum. 2-Pentadecanone (18.61%), eugenol (17.18%), 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester (13.19%), and (E,E)-farnesylacetone (7.15%) were the major compounds among the 14 identified components which accounted for 88.48% of the total oil of F. tataricum. Eugenol (12.22%), (E)-3-hexen-1-yl acetate (8.03%), linalool oxide (7.47%), 1-hexanol (7.07%), and benzothiazole (6.72%) were the main compounds of the 20 identified components which accounted for 90.23% of the total oil of F. cymosum. The three VOs were screened to have broad spectrum antibacterial activity with minimum inhibitory concentration (MIC) values ranged from 100.0 μg/mL to 800.0 μg/mL against the tested bacteria, and their median inhibitory concentration (IC50) values were from 68.32 μg/mL to 452.32 μg/mL. Xanthomonas vesicatoria was the most sensitive bacterium. Moreover, the flower VOs of F. esculentum, F. tataricum and F. cymosum also exhibited noteworthy antioxidant capacity with the IC50 value of 354.15 μg/mL, 210.63 μg/mL, and 264.92 μg/mL for the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, and the value of 242.06 μg/mL, 184.13 μg/mL, and 206.11 μg/mL respectively for the β-carotene-linoleic bleaching test. These results suggested the volatile oils of buckwheat flowers could be potential resource of natural antimicrobial and antioxidant agents.

Anthocyanidin reductase (ANR) is a key enzyme in the ANR biosynthetic pathway of flavan-3-ols and proanthocyanidins (PAs) in plants. Herein, we report characterization of the ANR pathway of flavan-3-ols in Shuchazao tea (Camellia sinesis), which is an elite and widely grown cultivar in China and is rich in flavan-3-ols providing with high nutritional value to human health. In our study, metabolic profiling was preformed to identify two conjugates and four aglycones of flavan-3-ols: (-)-epigallocatechin-gallate [(-)-EGCG], (-)-epicatechin-gallate [(-)-ECG], (-)-epigallocatechin [(-)-EGC], (-)-epicatechin [(-)-EC], (+)-catechin [(+)-Ca], and (+)-gallocatechin [(+)-GC], of which (-)-EGCG, (-)-ECG, (-)-EGC, and (-)-EC accounted for 70-85% of total flavan-3-ols in different tissues. Crude ANR enzyme was extracted from young leaves. Enzymatic assays showed that crude ANR extracts catalyzed cyanidin and delphinidin to (-)-EC and (-)-Ca and (-)-EGC and (-)-GC, respectively, in which (-)-EC and (-)-EGC were major products. Moreover, two ANR cDNAs were cloned from leaves, namely CssANRa and CssANRb. His-Tag fused recombinant CssANRa and CssANRb converted cyanidin and delphinidin to (-)-EC and (-)-Ca and (-)-EGC and (-)-GC, respectively. In addition, (+)-EC was observed from the catalysis of recombinant CssANRa and CssANRb. Further overexpression of the two genes in tobacco led to the formation of PAs in flowers and the reduction of anthocyanins. Taken together, these data indicate that the majority of leaf flavan-3-ols in Shuchazao's leaves were produced from the ANR pathway. [ABSTRACT FROM AUTHOR]

Suzuki-Miyaura coupling reactions are promoted by Pd complexes ligated with C2-symmetric multi-dentate N-heterocyclic carbenes derived in situ from Pd(OAc)2 and imidazolium salts. Good to excellent yields were obtained for aryl bromides as substrates. Turnover numbers of up to 105 could be achieved with 5 x 10-4 mol% of Pd(OAc)2/1 x 10-3 mol% NHC precatalyst in 24 h. [ABSTRACT FROM AUTHOR]