Levels Of Inhibitory Effects Research Articles

Coriaceumins A-D, the First Nitrogen-Containing Crenulide Diterpenoids from the Brown Alga Dictyota coriacea Collected in the East China Sea.

A phytochemical investigation of an East China Sea collection of the brown alga Dictyota coriacea has led to the isolation of four novel nitrogen-containing crenulide diterpenoids, named coriaceumins A-D (1-4), two rare nitrogenous xenicane diterpenoids, dictyolactams C (5) and D (6), and one known crenulide diterpenoid, hydroxycrenulide (7). The structures of the new compounds were elucidated by detailed spectroscopic data analyses, including HRESIMS and 1D/2D NMR. The absolute configurations were determined by a comparison of the experimental ECD spectra with the spectra computed by DFT-based quantum chemical calculations. Coriaceumins A-D (1-4) represent the first examples of nitrogen-containing crenulide diterpenoids. In a bioassay, compounds 2, 3, 5, and 7 were found to exhibit different levels of inhibitory effects against protein tyrosine phosphatase 1B (PTP1B) with IC50 values ranging from 7.3 to 19 μM. In addition, the primary structure-activity relationships of all the isolates were summarized.

Regioselective synthesis, structural and bioactivity of acetylated 1,5-benzodiazepin-2-one derivatives — X-ray crystallography, DFT and molecular docking approaches

Benzodiazepines, a well-studied class of seven-membered aromatic heterocycles containing two nitrogen atoms, have shown great promise as therapeutic agents. Efficient protocols have been developed to synthesize a variety of functionalized benzodiazepines. This study focuses on the synthesis of three derivatives of 1,5-benzodiazepin-2-one through regioselective acetylation using acetyl chloride under various conditions. One of the derivatives was characterized for its molecular and crystal structure using X-ray crystallography, Hirshfeld surfaces, and density functional theory computations (at wB97X-D/aug-cc-pVTZ level). The synthesized compounds were then subjected to in vitro evaluation to assess their antibacterial and antifungal activities against multiple strains. Additionally, their antioxidant and anti-inflammatory properties were examined. The results showed different levels of inhibitory effects on the growth of microorganisms, with all compounds displaying moderate to significant biological activities. Furthermore, molecular docking simulations were conducted to investigate the binding interactions of the compounds with bacterial and fungal targets. This research enhances our understanding of the chemistry of benzodiazepine derivatives and further highlights their therapeutic potential.

Sesquiterpenes from Ambrosia artemisiifolia and their allelopathy.

Ambrosia artemisiifolia, an invasive plant, has seriously harmed the agricultural production, native ecosystems and human health. Allelopathy is an important reason for the successful invasion of this alien plant. However, the chemical basis, action effects, action mechanism and release pathway of its allelopathy remain unclear. To address these problems, four sesquiterpenes (1–4), consisting of three new sesquiterpenes (1–2, 4), were isolated from the whole plant of A. artemisiifolia using a variety of column chromatography techniques, and identified using HR-ESIMS, 1D-NMR, 2D-NMR, and ECD. All the compounds exhibited different levels of inhibitory effects on three native plants (Setaria viridis, Digitaria sanguinalis, Chenopodium album) and one model plant (Arabidopsis thaliana), especially compound 1. In addition, the preliminary action mechanism of active compound 1 was revealed by FDA/PI staining assay. Furthermore, the allelopathic substances 1–3 were released into environment through the root secretion pathway by UPLC-MS/MS analyses.

Abstract P2-05-05: Evaluation of pan-HER and c-MET inhibitors tested ex vivo in primary HER2- breast cancer cells with hyperactive c-MET and ErbB family signaling

Abstract Background: To elucidate the role of c-Met signaling and its involvement with ErbB signaling as a cancer driver, a new assay using an impedance biosensor, the CELx multi-pathway signaling function (CELx MP) test, was developed. The CELx MP Test measures ex vivo real-time live cell response to specific ErbB and c-Met agonists to diagnose breast tumors with hyperactive HER1, HER2, HER3, HER4, and c-MET signaling activity. A recent study quantified c-MET and ErbB-driven signaling activity in epithelial cell samples derived from fresh breast tumor specimens obtained from 74 HER2- breast cancer patients. Of the cell samples tested, 20 of 74, (27.0%; 95% CI=18%-38%) had both hyperactive c-MET signaling and at least one hyperactive ErbB-family receptor signaling. Using primary breast cancer cells with hyperactive c-MET and ErbB signaling and the CELx MP test, the current study set out to: 1) determine the IC50 values of six pan-HER and five c-MET inhibitors; and 2) characterize the efficacy of combinations of each pan-HER inhibitor with each c-MET inhibitor. Methods: Epithelial cells from six HER2- tumor specimens with hyperactive c-MET and ErbB-driven signaling were obtained. Real-time live cell response to specific ErbB and c-Met agonists (NRG1b, EGF, or HGF) alone and in combination, with or without one of six pan-HER antagonists (neratinib, lapatinib, ibrutinib, dacomitinib, sapitinib, poziotinib) or one of five c-MET antagonists (tepotinib, cabozantinib, crizotinib, capmatinib, or savolitinib) was quantified using an xCELLigence RTCA impedance biosensor. Each individual drug IC50 was determined using a 1000-fold, 5-point, dose response curve with a single fixed concentration of a corresponding agonist. For the drug combination efficacy studies, fixed concentrations of the agonist mixture and clinically relevant concentrations of combinations of the antagonists were used to determine the percentage inhibition of the ErbB and c-MET signaling. Results: The IC50 values for the individual c-MET and pan-HER inhibitors ranged from 3.10nM - 28nM and 2.67nM – 137.27nM, respectively. In the drug efficacy studies, an average of at least 80% of the ErbB and c-MET signaling activated by NRG1, EGF, and HGF co-stimulation was inhibited by each combination of c-MET and pan-HER inhibitors. c-Met Inhibitor Resultsc-MET inhibitorIC50 (nM)Avg Inhibition (%) w/diff ErbBi's Capmatinib3.1094Savolitinib3.3298Tepotinib14.7096Cabozantinib27.3699Crizotinib28.21100 Pan-HER Inhibitor ResultsPan-HER inhibitorIC50 (nM)Avg Inhibition (%) w/diff c-METi's Poziotinib2.67100Neratinib4.81100Ibrutinib13.1099Dacomitinib22.06100Sapitinib41.2898Lapatinib137.2780 Conclusions: The CELx MP test using live cells measures IC50 values comparable to those derived using cell-free methods. Every combination of pan-HER and c-MET inhibitors provided comparably high (at least 80%) levels of inhibitory effect ex vivo. This suggests the sub-group of HER2- breast cancer patients diagnosed with coincident hyperactive c-MET and ErbB signaling by the CELx Test may respond to virtually any pan-HER and c-Met inhibitor combination. Studying combinations designed to minimize drug toxicities without sacrificing efficacy should thus be possible. Citation Format: Laing LG, Burns DJ, Khan S, MacNeil IA, Rich BE, Kharbush SM, Soltani SM, Sullivan BF. Evaluation of pan-HER and c-MET inhibitors tested ex vivo in primary HER2- breast cancer cells with hyperactive c-MET and ErbB family signaling [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-05-05.

Identification of new promising plant-based lead compounds for inhibition of prokaryotic replicative DNA polymerases: combination of in silico and in vitro studies

Emerging widespread bacterial resistance to current antibiotics with traditional targets is one of the major global concerns. Therefore, so many investigations are exploring the potential of other druggable macromolecules of bacteria such as replication machinery components that are not addressed by previous antibiotics. DNA polymerase is the major part of this machine. However, a few studies have been done on it so far. In this respect, we report the discovery of four new plant-based leads against DNA polymerase (pol) IIIC (three leads) and pol IIIE (one lead) of Gram-positive and negative bacteria by combining a sequentially constrained high-throughput virtual screenings on Traditional Chinese Medicine Database with in vitro assays. The compounds displayed relatively good levels of inhibitory effect. They were active against their designated targets at micromolar concentrations. The IC50 values for them are ranged from 25 to 111 μM. In addition, they showed minimum inhibitory concentrations in the range of 8–128 μg/mL against five representatives of pathogenic bacteria species. However, they were inactive against Pseudomonas aeruginosa. Given these results, these leads hold promise for future modification and optimization to be more effective in lower concentrations and also against most of the important bacterial species.Communicated by Ramaswamy H. Sarma

Anti-inflammatory isoflavones and isoflavanones from the roots of Pongamia pinnata (L.) Pierre

A phytochemical study on the roots of Pongamia pinnata afforded five new isoflavone and isoflavanone derivatives (1–5), including two previously undescribed phenylisoflavones possessing an 1,2-oxetane ring, along with 21 known compounds (6–26) among which compound 18 is the first time to be isolated from nature. The structures of the isolated compounds were determined on the basis of 1D, 2D NMR, and HRESIMS. The absolute configurations of the compounds were assigned via analysis of the specific rotations and circular dichroism (CD) spectra, as well as by comparison of the calculated and experimental electronic circular dichroism (ECD) data. All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated BV-2 microglial cells. Twelve compounds exhibited different levels of inhibitory effects against NO production, and compound 1 showed the best activity with an IC50 value at 9.0 μM.

Enhancement of 1-deoxynojirimycin content in leaf extracts of Morus alba L. by lactic acid bacteria fermentation

The α-glucosidase inhibitor plays a key role to control postprandial blood glucose levels in diabetic patients with type 2 diabetes and 1-deoxynojirimycin (DNJ) is the main αglucosidase inhibitor in mulberry (Morus alba L.). Mulberry leaf was extracted with 30% ethanol and the extracts were fermented using seven kinds of lactic acid bacteria (LABs) in order to increase the contents of DNJ in the leaf extracts. The DNJ content of Lactobacillus acidophilus among LABs examined in this study was the highest to 21.77 μg/ml and appeared to be about 2.5 times higher than 8.38 μg/ml of non-fermented control. All of the fermented mulberry leaf extracts appeared to enhance a certain degree of α-glucosidase inhibitory activity and the IC50 values against α-glucosidase, compared to the non-fermented extract. Among LABs, L. casei KCTC 3109 (Inhibition = 43.83% ± 0.98%, IC50=290.06 μg/ml) showed more remarkable inhibitory effects than the non-fermented control (30.78%±1.89%, IC50=429.80 μg/ml). Furthermore, dose-dependent inhibition of the extract showed a significant level of inhibitory effects within only the range of 1 mg/ml concentration. The results suggest that the fermentation method with LABs can enhance the increase of the contents of hypoglycemic constituents such as DNJ on ethanol extracts of mulberry leaves.

The Inorganic Side of NGF: Copper(II) and Zinc(II) Affect the NGF Mimicking Signaling of the N-Terminus Peptides Encompassing the Recognition Domain of TrkA Receptor.

The nerve growth factor (NGF) N-terminus peptide, NGF(1–14), and its acetylated form, Ac-NGF(1–14), were investigated to scrutinize the ability of this neurotrophin domain to mimic the whole protein. Theoretical calculations demonstrated that non-covalent forces assist the molecular recognition of TrkA receptor by both peptides. Combined parallel tempering/docking simulations discriminated the effect of the N-terminal acetylation on the recognition of NGF(1–14) by the domain 5 of TrkA (TrkA-D5). Experimental findings demonstrated that both NGF(1–14) and Ac-NGF(1–14) activate TrkA signaling pathways essential for neuronal survival. The NGF-induced TrkA internalization was slightly inhibited in the presence of Cu2+ and Zn2+ ions, whereas the metal ions elicited the NGF(1–14)-induced internalization of TrkA and no significant differences were found in the weak Ac-NGF(1–14)-induced receptor internalization. The crucial role of the metals was confirmed by experiments with the metal-chelator bathocuproine disulfonic acid, which showed different inhibitory effects in the signaling cascade, due to different metal affinity of NGF, NGF(1–14) and Ac-NGF(1–14). The NGF signaling cascade, activated by the two peptides, induced CREB phosphorylation, but the copper addition further stimulated the Akt, ERK and CREB phosphorylation in the presence of NGF and NGF(1–14) only. A dynamic and quick influx of both peptides into PC12 cells was tracked by live cell imaging with confocal microscopy. A significant role of copper ions was found in the modulation of peptide sub-cellular localization, especially at the nuclear level. Furthermore, a strong copper ionophoric ability of NGF(1–14) was measured. The Ac-NGF(1–14) peptide, which binds copper ions with a lower stability constant than NGF(1–14), exhibited a lower nuclear localization with respect to the total cellular uptake. These findings were correlated to the metal-induced increase of CREB and BDNF expression caused by NGF(1–14) stimulation. In summary, we here validated NGF(1–14) and Ac-NGF(1–14) as first examples of monomer and linear peptides able to activate the NGF-TrkA signaling cascade. Metal ions modulated the activity of both NGF protein and the NGF-mimicking peptides. Such findings demonstrated that NGF(1–14) sequence can reproduce the signal transduction of whole protein, therefore representing a very promising drug candidate for further pre-clinical studies.

Characterization of functional properties of Enterococcus faecium strains isolated from human gut.

The aim of this work was to characterize the functional properties of Enterococcus faecium strains identified after isolation from human faeces. Of these isolates, strain R13 showed the best resistance to low pH, bile salts, and survival in the simulated in vitro digestion assay, and demonstrated an important level of adhesion to hexadecane as a potential probiotic candidate. Analysis of the antibiotic resistance of E. faecium strains indicated that in general these isolates were sensitive to the tested antibiotics and no strain appeared to be resistant to vancomycin. Examination of the virulence determinants for E. faecium strains demonstrated that all strains contained the virulence genes common in gut- and food-originated enterococci, and strain R13 harboured the lowest number of virulence genes. Additionally, no strain contained the genes related to cytolysin metabolism and showed hemolytic activity. The antimicrobial role of E. faecium strains was tested against several pathogens, in which different levels of inhibitory effects were observed, and strain R13 was inhibitory to all tested pathogens. PCR screening of genes encoding enterocin A and B indicated the presence of these genes in E. faecium strains. Preliminary characterization of bacteriocins revealed that their activity was lost after proteolytic enzyme treatments, but no alteration in antimicrobial activity was observed at different pHs (3.5 to 9.5) and after heat treatments. In conclusion, this study revealed the functional characteristics of E. faecium R13 as a gut isolate, and this strain could be developed as a new probiotic after further tests.

Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation

Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51 × faster), ostrich oil (1.46 × faster), and rhea oil (1.64 × faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35 × slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions.

Abstract 1754: BPR2P001S0, a Coumarin derivative, induced cell cycle arrest in A549 through inhibiting PDPK1 activity

Abstract Lung cancer is one of the most common causes of cancer deaths in the world, and the emergence of resistant lung cancer cells can lead to treatment failure. The development of new drugs to treat lung cancer, especially those resistant lung cancer cells, is urgent. Previously we identified that coumarin could inhibit replication of human lung cancer A549 cells. The efficacy of 284 coumarin derivatives on human lung cancer A549 cells was examined, and BPR2P001S0 was the most potent compound. BPR2P001S0 exhibited growth inhibition and apoptotic activity on A549 cells with an IC50 of 10 nM. A similar level of inhibitory effects was also observed in cisplatin-resistant A549 cells (IC50 = 12.5 nM). The ability of colony formation and migration capability of A549 cells decreased significantly in the presence of BPR2P001S0. In cell cycle analysis, BPR2P001S0 induced cell cycle arrest at the G0/G1 phase through down-regulation of cyclin D1 and Cdk4 protein expression. The expression of cyclinD1/Cdk4 regulatory protein, Akt, was also decreased. Subsequently, we found that the expression level of Ser241 phosphorated PDPK1 protein, an Akt activator in Akt pathway, was also reduced. By molecular docking analysis, we found that the reduced PDPK1 phosphorylation is likely resulted from the allosteric effect of interactions between BPRHIV001 and PDPK1. In conclusion, our results suggest that the anti-tumor activity of BPR2P001S0 is likely resulting from its ability to interfere with PDPK1 autophosphorylation at Ser241, which leads to reduced Akt protein and subsequent cyclin D1 degradation. Citation Format: Pi-Han Lin, Tzu-Ming Jao, Yu-Lin Hung, Hsing-Pang Hsieh, Ya-Chien Yang, Sui-Yuan Chang. BPR2P001S0, a Coumarin derivative, induced cell cycle arrest in A549 through inhibiting PDPK1 activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1754. doi:10.1158/1538-7445.AM2015-1754

The discovery of potential tubulin inhibitors: A combination of pharmacophore modeling, virtual screening, and molecular docking studies

The microtubules play a significant role in the growth and functions of cells, and hence, inhibition of microtubule assembly has emerged as one of the most promising strategies for the treatment of cancer. To clarify the essential structure-activity relationship of tubulin inhibitors as well as identify novel leads, three-dimensional pharmacophore models were established on the basis of known tubulin inhibitors. The model (Hypo1) that had the highest correlation coefficient (0.9330), the largest cost difference (66.911) and the lowest RMSD value (0.70258) was chosen as the best pharmacophore model. Hypo1 was validated using test set, Fischer randomization and leave-one-out methods and a decoy set. Then, the model was used as a 3D structural query to search the Specs database. We subsequently refined the retrieved hit compounds by subjecting them to drug-like filtrations and molecular docking studies. Finally, we selected 10 compounds on the basis of the necessary interactions with the key residues to be experimentally validated in a bioassay. We showed that all compounds had some level of inhibitory effect on MCF-7 breast cancer cell line where the most promising three candidates exhibited an inhibition rate of more than 80% at a concentration of 100μmol/L.

Novel 5‐Acetyl‐3‐aryl‐2‐thioxo‐dihydropyrimidine‐4,6(1H,5H)‐diones: One Pot Three‐Component Synthesis, Characterization and Antibacterial Activity

A series of new 5‐substituted thiobarbituric acid derivatives 5‐acetyl‐3‐aryl‐2‐thioxo‐dihydropyrimidine‐4,6(1H,5H)‐diones (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h) were synthesized by one pot cyclocondensation of 1‐aroyl‐3‐arylthioureas with malonic acid in the presence of acetic anhydride. These compounds exist in equilibrium with their enolic tautomeric forms 5‐(1‐hydroxy ethylidene)‐3‐aryl‐2‐thioxo‐dihydropyrimidine‐4,6‐(1H,5H)‐diones. The structures were confirmed by spectroscopic data, elemental analyses and in case of the 2d by single crystal X‐ray diffraction data. A plausible mechanism for the formation of products is also proposed. Compounds (2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h) were evaluated for their preliminary antibacterial activity against a representative panel of Gram positive and Gram negative bacteria using levofloxacin as the reference drug and were found to exhibit promising activity. The tested compounds displayed different levels of inhibitory effects on bacterial strains. Compound 2b showed the maximum efficacy against pathogenic bacteria and was identified as the lead molecule for further structural modifications.

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

In the reaction of 2-amino-3-carbethoxythiophene derivative 2b with hydrazine hydrate the respective aminocarbohydrazide 3 was isolated. Treatment of the latter product with carbon disulfide in alkaline medium caused a heterocyclization to give 1,3,4-oxadiazole-2-thione 5 rather than 3-amino-2-thioxothieno[2,3- d ]pyrimidin-4-one 4 , which could be obtained on treatment of carbohydrazide 3 with thiourea. The structure of products 4 and 5 was proved by spectroscopic methods and chemical transformations. Derivatization led to two novel series of condensed and uncondensed thiophenes, which were of significant interest for biological study. Since compound 4 contains two adjacent reactive functional groups, it reacted readily with different electrophilic reagents to provide a series of thieno[2,3-d]pyrimidin-4-one derivatives with annelated bridgehead nitrogen heterocycles 8 - 11 , whereas a second series of 3-heteroaryl-substituted thiophenes 13 - 17 was obtained by thioamide functionalization in 1,3,4-oxadiazole derivative 5 using various chemical reagents. The new thiophene-based derivatives were evaluated for their preliminary antimicrobial activity against a representative panel of Gram-positive and Gram-negative bacteria as well as fungi strains. The compounds tested displayed different levels of inhibitory effects, with the assays carried out on two pathogenic bacteria and two pathogenic fungi. Of these compounds, the monocyclic aminothiophene derivative 15 showed the highest effect on pathogenic bacteria, while the tricyclic condensed thiophene derivative 8 was observed to have the same inhibitory effect against pathogenic mould ( Aspergillus flavus ) as the reference drug Amphotericin B. For those derivatives belonging to first series of condensed thiophenes with annelated bridgehead nitrogen heterocycles, it has been observed that the antibacterial effect was in general found to be significantly higher than the corresponding uncondensed analogues. Although most of the condensed and uncondensed thiophenes under investigation showed generally remarkable in vitro antibacterial activity, unfortunately, no significant antifungal activity was observed with any of the compounds tested except for 8. Surprisingly, compound 8 displayed an excellent effect on fungus ( A. flavus ) on the one hand, whereas the lowest effect on bacteria on the other. The attachment of a triazolothiadiazine moiety to a thiophene ring could be considered as a promising strategy for the development of new therapeutic antibacterial agents related to the aminothiophene system.

Purification of beta-glucosidase from olive ( Olea europaea L.) fruit tissue with specifically designed hydrophobic interaction chromatography and characterization of the purified enzyme

An olive ( Olea europaea L.) β-glucosidase was purified to apparent homogeneity by salting out with ammonium sulfate and using specifically designed sepharose-4B- l-tyrosine-1-napthylamine hydrophobic interaction chromatography. The purification was 155 fold with an overall enzyme yield of 54%. The molecular mass of the protein was estimated as ca. 65 kDa. The purified β-glucosidase was effectively active on p-/ o-nitrophenyl-β- d-glucopyranosides ( p-/ o-NPG) with K m values of 2.22 and 14.11 mM and V max values of 370.4 and 48.5 U/mg, respectively. The enzyme was competitively inhibited by δ-gluconolactone and glucose against p-NPG as substrate. The K i and IC 50 values of δ-gluconolactone were determined as 0.016 mM and 0.23 mM while the enzyme was more tolerant to glucose inhibition with K i and IC 50 values of 6.4 mM and 105.5 mM, respectively, for p-NPG. The effect of various metal ions on the purified β-glucosidase was investigated. Of the ions tested, only the Fe 2+ increased the activity while Cd 2+ Pb 2+ Cu 2+, Ni +, and Ag + exhibited different levels of inhibitory effects with K i and IC 50 values of 4.29 × 10 −4 and 0.38 × 10 −4, 1.26 × 10 −2 and 5.3 × 10 −3, 2.26 × 10 −4 and 6.1 × 10 −4, 1.04 × 10 −4 and 0.63 × 10 −4, 3.21 × 10 −3 and 3.34 × 10 −3 mM, respectively.

Effects of monomers eluted from dental resin restoratives on osteoblast‐like cells

Resin-modified glass-ionomer (RMGIC) has been demonstrated to exhibit inhibition on the growth and differentiation of osteoblasts on its surface. In this study, the hypothesis that the different levels of inhibitory effects on osteoblasts of resin restoratives depend on elution of unpolymerized monomers was examined. Release of monomers from cured specimens of Bis-GMA/TEGDMA-composites, MMA-resin cements, or HEMA-containing RMGIC was determined and osteoblast-like MC3T3-E1 cells were cultured in the presence of 100-10 microg/mL of TEGDMA, 10-1 microg/mL of MMA, or 400-50 microg/mL of HEMA according to the release concentrations. Cell proliferation, alkaline phosphatase (ALP) activity, the expression of osteoblastic markers, and mineralized tissue formation were evaluated. TEGDMA and MMA at the concentrations tested did not affect the growth of MC3T3-E1 and exhibited little harmful effects on their differentiation and mineralization. On the contrary, HEMA inhibited proliferation, ALP activities, the expression of osteocalcin, and mineralized tissue formation at 200 microg/mL or more. These results indicate that HEMA at the concentrations similar to that observed in elution tests affected osteoblastic proliferation, differentiation, and mineralization, suggesting that elution of unreacted HEMA could be the main component of the adverse effects of RMGIC on osteoblast-like cells and influences of resin restoratives on the osteoblasts are possibly dependant on release characteristics of unpolymerized monomers.

Influence of trypan blue and related compounds on 35S-sulfate metabolism of cartilage in vitro

When slices of calf costal cartilage are incubated in Tyrode solution and allowed to synthesize 35S-labelled acid-mucopolysaccharides, the presence of trypan blue dissolved in the medium inhibits the synthesis. Other related dyes such as Evans blue and dianil blue 2R inhibit the synthesis to a lesser degree. Congo red, on the other hand, is a very strong inhibitor. Naphthalene sulfonic acids resembling in chemical structure the naphthalene moieties of the dye molecules show inhibition to a corresponding degree. Although the mechanism of inbihition of sulfo-mucopolysaccharide synthesis is not obvious from these experiments, the possibility is suggested that the dyes may be interfering in the metabolism of the embryo leading to malformations. Since the dyes behave in a characteristic manner showing different levels of inhibitory effect which can be broadly assigned to a particular configuration of the molecule, it may be possible to find a teratogenically active site in the molecule.