Synthesis and anti-proliferative activity of dehydroabietinol derivatives bearing a triazole moiety.

In search of more efficacious antitumor agents, a series of novel dehydroabietinol derivatives containing a triazole moiety was synthesized, and evaluated for cytotoxicity against four human cancer cell lines. Many exhibited superior cytotoxic profiles compared to the parent molecule, dehydroabietic acid. In particular, compounds 5g, 5i and 5j exhibited promising cytotoxicity with IC50 values ranging from 4.84 to 9.62 µM against all the test cell lines. Cell clone formation and migration tests of compound 5g showed that it not only effectively inhibited the formation of MGC-803 cell colonies but also inhibited the MGC-803 cell migration and invasion. Additionally, the preliminary pharmacological mechanism indicated compound 5g induced apoptosis, arrested the mitotic process at the G0/G1 phase of the cell cycle, reduced the mitochondrial membrane potential, and increased the intracellular ROS and Ca2+ levels.

Synthesis, Antifungal Activity, 3D-QSAR and Controlled Release on Hydrotalcite Study of Longifolene-Derived Diphenyl Ether Carboxylic Acid Compounds.

Twenty-two novel longifolene-derived diphenyl ether-carboxylic acid compounds 7a-7v were synthesized from renewable biomass resources longifolene, and their structures were confirmed by FT-IR, 1H NMR, 13C NMR, and HRMS. The preliminary evaluation of in vitro antifungal activity displayed that compound 7b presented inhibition rates of 85.9%, 82.7%, 82.7%, and 81.4% against Alternaria solani, Cercospora arachidicola, Rhizoctonia solani, and Physalospora piricola, respectively, and compound 7l possessed inhibition rates of 80.7%, 80.4%, and 80.3% against R. solani, C. arachidicola, P. piricola, respectively, exhibiting excellent and broad-spectrum antifungal activities. Besides, compounds 7f and 7a showed significant antifungal activities with inhibition rates of 81.2% and 80.7% against A.solani, respectively. Meanwhile, a reasonable and effective 3D-QSAR mode (r2 = 0.996, q2 = 0.572) has been established by the CoMFA method. Furthermore, the drug-loading complexes 7b/MgAl-LDH were prepared and characterized. Their pH-responsive controlled-release behavior was investigated as well. As a result, complex 7b/MgAl-LDH-2 exhibited excellent controlled-releasing performance in the water/ethanol (10:1, v:v) and under a pH of 5.7.

Design, Synthesis, and Molecular Docking Study of Novel 3-Cyanopyridine Derivatives for the Anti-Cancer Drug Target Survivin Protein.

Survivin is an important member of the antiapoptotic protein family and controls the cell's life cycle. Overexpression of survivin in tumor cells leads to inhibition of apoptosis, thus contributing to cancer cell proliferation. The largest binding pocket in the survivin dimer was located in the BIR domain. The key to the efficacy of 3-cyanopyridines was their surface interaction with the survivin amino acid Ile74. METHODS: Through the optimization of the 3-cyanopyridine, 29 new compounds with a 3- Cyanopyridine structure were designed, synthesized, and characterized by NMR, IR, and mass spectrometry. The antitumor activity of the compounds in vitro was detected by the MTT method. RESULTS: In vitro anti-tumor experiments showed that some compounds exhibited good anti-cancer effects. The IC50 values of the compound 2-amino-6-(2,4-difluorophenyl)-4-(4-hydroxyphenyl) nicotinonitrile (10n) against human liver cancer (Huh7), human glioma (U251), and human melanoma (A375) cells were 5.9, 6.0 and 7.2 µM, respectively. The IC50 values of the compound 6-(2,4-difluorophenyl)- 4-(4-hydroxyphenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (9o) against Huh7, U251 and A375 cells were 2.4, 17.5 and 7.2 µM, respectively, which were better than those of 10- hydroxycamptothecin and 5-fluorouracil. Analysis of the results of molecular dynamics simulation established that the BIR domain is the optimal binding site on the survivin protein, and the fingerprints of the eight most active compounds and the molecular docking to the survivin protein are analyzed. CONCLUSION: 3-Cyanopyridine is an excellent backbone for antitumor lead compounds, 10n and 9o, as derivatives of 3-Cyanopyridine are excellent survivin protein-targeting inhibitors worthy of further study. The key factor in inhibiting survivin protein through the action of amino acid Ile74.

Development and evaluation of a hydrogenated rosin (ß-acryloxyl ethyl) ester-bonded silica stationary phase for high-performance liquid chromatography separation of paclitaxel from yew bark.

Paclitaxel (PTX) is a complex diterpenoid anticancer drug whose separation from yew biomass poses a significant challenge. In this study, a new stationary phase comprising hydrogenated rosin (ß-acryloxyl ethyl) ester (HRE)-bonded silica (HRE@SiO2) is developed to separate and purify PTX from crude yew-bark extract using high-performance liquid chromatography. In HRE@SiO2, HRE molecules, which are functional ligands, are bonded to the surface of a silica gel matrix using a coupling agent, (3-mercaptopropyl)trimethoxysilane. The proposed HRE@SiO2 stationary phase was characterized by Fourier-transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, scanning electron microscopy, laser diffraction granulometry, and nitrogen gas adsorption. The HRE@SiO2 column exhibited excellent chromatographic performance, satisfactory performance reproducibility, and typical reversed-phase chromatographic behavior. An HRE@SiO2 column was used to separate PTX and its analogs, achieving resolutions exceeding 7.43 for consecutively eluted species. Stoichiometric displacement theory for retention (SDT-R), the van Deemter equation, and van 't Hoff plots were used to analyze the separation mechanism and properties of the HRE@SiO2 column. The results showed that hydrophobic interactions determine the analyte retention and the separation of PTX and its analogs on an HRE@SiO2 column is an exothermic process driven by enthalpy. Furthermore, an HRE@SiO2 column was employed to separate and purify PTX from crude yew-bark extract, increasing PTX purity from 6% to 82%. The findings of this study provide insights for developing rosin-based stationary phases for the separation of natural products.

Diffusion of water and protein drug in 1,4-butanediol diglycidyl ether crosslinked galactomannan hydrogels and its correlation with the physicochemical properties.

The aim of the present study was to obtain a better and safer galactomannan-based material for drug release applications. A novel epoxy-crosslinked galactomannan hydrogel (EGH) was prepared from guar gum using 1,4-butanediol diglycidyl ether as a crosslinking agent. The diffusion rate constant of water molecules in freeze-dried EGH positively correlated with water uptake/equilibrium swelling rate (WU/ESR), and the water molecules participated in Fickian diffusion. The ESR, WU/ESR, and bovine serum albumin (BSA) loading capacity of a customized EGH with a crosslinking density of 48.9% were 48.7 ± 0.15 g/g, 95.3%, and 56.4 mg/g, respectively. The release of BSA from freeze-dried EGH was affected by the WU/ESR and the pH; the release equilibrium time was ~40 h at pH 1.2, decreasing to ~24 h at pH 7.4. Furthermore, the cumulative release rate increased from 63.5% to 80.7% and the t50 decreased from 59 to 41 min upon changing from the acidic to basic pH. The release process conformed to the Ritger-Peppas and Hixson-Crowell models, and represented Fickian diffusion and chain relaxation. The EGH showed no cytotoxicity toward HeLa cells. Together, these results demonstrate the properties of a novel galactomannan-based hydrogel that can potentially be employed as a vehicle for drug delivery.

Physicochemical characterization of Gleditsia triacanthos galactomannan during deposition and maturation.

Gleditsia triacanthos polysaccharide, known as galactomannan, has not been exploited as a new functional material even though it possesses industrial potential in food and biomedicine. Galactomannans were recovered from the endosperm of seeds (15 weeks to 25 weeks after flowering) for deposition and maturation analysis. These galactomannans were characterized by using Nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and monosaccharide composition analysis (particularly the mannose to galactose ratio) and molecular weight, solubility, and rheological measurements. The ratio of the three parts in mature seeds was as follows: endosperm (36.67%), hull (34.41%), and embryo (28.92%). The M/G ratio increased from 2.53 to 3.24 between 15 and 23 weeks and then decreased to 3.16 in 25 weeks, consistent with the trends of rheology and solubility. The molecular weight (1.28 × 106 g/mol) and intrinsic viscosity (882.53 mL/g) reached the maximum at 23 weeks and then decreased. Additionally, NMR and XRD showed that the M/G ratio did not change the basic chemical structure but caused slight changes in crystallinity. The purpose of the study was to reveal the changes in galactomannan structure, rheology, and solubility during G. triacanthos galactomannan deposition and maturation to facilitate exploration of its potential industrial applications.

Synthesis and Antiproliferative Evaluation of Novel Hybrids of Dehydroabietic Acid Bearing 1,2,3-Triazole Moiety.

To discover novel potent cytotoxic diterpenoids, a series of hybrids of dehydroabietic acid containing 1,2,3-triazole moiety were designed and synthesized. The target compounds were characterized by means of FT-IR, 1H NMR, 13C NMR, ESI-MS and elemental analysis techniques. The in vitro cytotoxicity of these compounds was evaluated by standard MTT (methyl thiazolytetrazolium) assay against CNE-2 (nasopharynx), HepG2 (liver), HeLa (epithelial cervical), BEL-7402 (liver) human carcinoma cell lines and human normal liver cell (HL-7702). The screening results revealed that most of the hybrids showed significantly improved cytotoxicity over parent compound DHAA. Among them, [1-(3-fluorobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3c), and [1-(2-nitrobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3k) displayed better antiproliferative activity with IC50 (50% inhibitory concentration) values of 5.90 ± 0.41 and 6.25 ± 0.37 µM toward HepG2 cells compared to cisplatin, while they exhibited lower cytotoxicity against HL-7702. Therefore, the 1,2,3-triazole-hybrids could be a promising strategy for the synthesis of antitumor diterpenoids and it also proved the essential role of 1,2,3-triazole moiety of DHAA in the biological activity.

Synthesis and Biological Evaluation of Novel Dehydroabietic Acid-Oxazolidinone Hybrids for Antitumor Properties.

Novel representatives of the important group of biologically-active, dehydroabietic acid-bearing oxazolidinone moiety were synthesized to explore more efficacious and less toxic antitumor agents. Structures of all the newly target molecules were confirmed by IR, ¹H-NMR, 13C-NMR, and HR-MS. The inhibitory activities of these compounds against different human cancer cell lines (MGC-803, CNE-2, SK-OV-3, NCI-H460) and human normal liver cell line LO2 were evaluated and compared with the commercial anticancer drug cisplatin, using standard MTT (methyl thiazolytetrazolium) assay in vitro. The pharmacological screening results revealed that most of the hybrids showed significantly improved antiproliferative activities over dehydroabietic acid and that some displayed better inhibitory activities compared to cisplatin. In particular, compound 4j exhibited promising cytotoxicity with IC50 values ranging from 3.82 to 17.76 µM against all the test cell lines and displayed very weak cytotoxicity (IC50 > 100 µM) on normal cells, showing good selectivity between normal and malignant cells. Furthermore, the action mechanism of the representative compound 4j was preliminarily investigated by Annexin-V/PI dual staining, Hoechst 33258 staining, which indicated that the compound can induce cell apoptosis in MGC-803 cells in a dose-dependent manner and arrest the cell cycle in G1 phase. Therefore, 4j may be further exploited as a novel pharmacophore model for the development of anticancer agents.

Enhancement of ethanol production from green liquor-ethanol-pretreated sugarcane bagasse by glucose-xylose cofermentation at high solid loadings with mixed Saccharomyces cerevisiae strains.

BACKGROUND: Efficient cofermentation of glucose and xylose is necessary for economically feasible bioethanol production from lignocellulosic biomass. Here, we demonstrate pretreatment of sugarcane bagasse (SCB) with green liquor (GL) combined with ethanol (GL-Ethanol) by adding different GL amounts. The common Saccharomyces cerevisiae (CSC) and thermophilic S. cerevisiae (TSC) strains were used and different yeast cell mass ratios (CSC to TSC) were compared. The simultaneous saccharification and cofermentation (SSF/SSCF) process was performed by 5-20% (w/v) dry substrate (DS) solid loadings to determine optimal conditions for the co-consumption of glucose and xylose. RESULTS: Compared to previous studies that tested fermentation of glucose using only the CSC, we obtained higher ethanol yield and concentration (92.80% and 23.22 g/L) with 1.5 mL GL/g-DS GL-Ethanol-pretreated SCB at 5% (w/v) solid loading and a CSC-to-TSC yeast cell mass ratio of 1:2 (w/w). Using 10% (w/v) solid loading under the same conditions, the ethanol concentration increased to 42.53 g/L but the ethanol yield decreased to 84.99%. In addition, an increase in the solid loading up to a certain point led to an increase in the ethanol concentration from 1.5 mL GL/g-DS-pretreated SCB. The highest ethanol concentration (68.24 g/L) was obtained with 15% (w/v) solid loading, using a CSC-to-TSC yeast cell mass ratio of 1:3 (w/w). CONCLUSIONS: GL-Ethanol pretreatment is a promising pretreatment method for improving both glucan and xylan conversion efficiencies of SCB. There was a competitive relationship between the two yeast strains, and the glucose and xylose utilization ability of the TSC was better than that of the CSC. Ethanol concentration was obviously increased at high solid loading, but the yield decreased as a result of an increase in the viscosity and inhibitor levels in the fermentation system. Finally, the SSCF of GL-Ethanol-pretreated SCB with mixed S. cerevisiae strains increased ethanol concentration and was an effective conversion process for ethanol production at high solid loading.

Enhancement of fermentable sugar yield by competitive adsorption of non-enzymatic substances from yeast and cellulase on lignin.

BACKGROUND: Enhancement of enzymatic digestibility by some supplementations could reduce enzyme loading and cost, which is still too high to realize economical production of lignocellulosic biofuels. A recent study indicates that yeast hydrolysates (YH) have improved the efficiency of cellulases on digestibility of furfural residues (FR). In the current work, the components of YH were separated by centrifugation and size exclusion chromatography and finally characterized in order to better understand this positive effect. RESULTS: A 60.8% of nitrogen of yeast cells was remained in the slurry (YHS) after hydrothermal treatment. In the supernatant of YH (YHL), substances of high molecular weight were identified as proteins and other UV-absorbing compounds, which showed close molecular weight to components of cellulases. Those substances attributed to a synergetic positive effect on enzymatic hydrolysis of FR. The fraction of YHL ranged from 1.19 to 2.19 mL (elution volume) contained over 50% of proteins in YHL and had the best performance in stimulating the release of glucose. Experiment results proved the adsorption of proteins in YHL on lignin. CONCLUSIONS: Supplementation of cellulases with YH enhances enzymatic digestibility of FR mainly by a competitive adsorption of non-enzymatic substances on lignin. The molecular weight of these substances has a significant impact on their performance. Different strategies can be used for a good utilization of yeast cells in terms of biorefinery concept.