Molecules

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Open AccessArticle

Synthesis and Structural Characterization of Fluorinated Thiosemicarbazones

by Juan L. Bautista, Marcos Flores-Alamo, Jorge Tiburcio, Rebeca Vieto and Hugo Torrens

Molecules 2013, 18(10), 13111-13123; https://doi.org/10.3390/molecules181013111 - 22 Oct 2013

Cited by 12 | Viewed by 5531

Six new fluorinated thiosemicarbazones R‑C(R′)=N-NH-C(S)NH₂ (R = 2,4-C₆H₃F₂, R′ = H (1); R = 2,5-C₆H₃F₂, R′ = H (2); R = 2,6-C₆H₃F [...] Read more.

Six new fluorinated thiosemicarbazones R‑C(R′)=N-NH-C(S)NH₂ (R = 2,4-C₆H₃F₂, R′ = H (1); R = 2,5-C₆H₃F₂, R′ = H (2); R = 2,6-C₆H₃F₂, R′ = H (3); R = 3,4-C₆H₃F₂, R′ = H (4); R = 3,5-C₆H₃F₂, R′ = H (5) and R = 4-C₆H₄F, R′ = C₆H₅, (6)) have been prepared. The molecular structures of compounds 1 to 6 have been determined. Full article

(This article belongs to the Section Organic Chemistry)

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253 KiB

Open AccessArticle

Non-Classical Transformation of Benzendiazonium Hydrogen Sulfates. Access to 1,3-Dimethylisochromeno[4,3-c]pyrazol-5(1H)-one, a Potential Benzodiazepine Receptor Ligand

by Benedetta Maggio, Demetrio Raffa, Maria Valeria Raimondi and Giuseppe Daidone

Molecules 2013, 18(10), 13096-13110; https://doi.org/10.3390/molecules181013096 - 22 Oct 2013

Cited by 3 | Viewed by 5853

Abstract

The compound 2-((1,3-dimethyl-1H-pyrazol-5-yl)(methyl)carbamoyl)benzene-diazonium hydrogen sulfate (10) was reacted with copper sulfate and sodium chloride, in the presence of ascorbic acid as reducing agent, to afford a mixture of the chlorinated epimers 4′-chloro-2,2′,5′-trimethyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (18) and (19), [...] Read more.

The compound 2-((1,3-dimethyl-1H-pyrazol-5-yl)(methyl)carbamoyl)benzene-diazonium hydrogen sulfate (10) was reacted with copper sulfate and sodium chloride, in the presence of ascorbic acid as reducing agent, to afford a mixture of the chlorinated epimers 4′-chloro-2,2′,5′-trimethyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (18) and (19), the epimers 4′-hydroxy-2,2′,5′-trimethyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (20) and (21), and N-(1,3-dimethyl-1H-pyrazol-5-yl)benzamide (22). Under the foregoing conditions, diazonium salt 10 affords neither the 2-chloro-N-(1,3-dimethyl-1H-pyrazol-5-yl)-N-methylbenzamide (23) nor the tricyclic derivative 24, the classical products of the Sandmeyer and Pschorr reactions, respectively. Finally, by heating 20 at 210 °C the compound 1,3-dimethylisochromeno[4,3-c]pyrazol-5(1H)-one (24) was obtained. The transformation under the above conditions of 2-((4-chloro-3-methyl-1-phenyl- 1H-pyrazol-5-yl)(methyl)carbamoyl)benzendiazonium hydrogen sulphate (11) afforded 4′,4′-dichloro-2,5′-dimethyl-2′-phenyl-2′,4′-dihydrospiro[isoindoline-1,3′-pyrazol]-3-one (29) as the sole reaction product. Full article

(This article belongs to the Section Organic Chemistry)

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3562 KiB

Open AccessArticle

Synthesis of Laboratory Ultrasound Contrast Agents

by Jingam Park, Donghee Park, Unchul Shin, Sanghyub Moon, Chihyun Kim, Han Sung Kim, Hyunjin Park, Kiju Choi, Bongkwang Jung, Jaemin Oh and Jongbum Seo

Molecules 2013, 18(10), 13078-13095; https://doi.org/10.3390/molecules181013078 - 21 Oct 2013

Cited by 12 | Viewed by 7447

Abstract

Ultrasound Contrast Agents (UCAs) were developed to maximize reflection contrast so that organs can be seen clearly in ultrasound imaging. UCAs increase the signal to noise ratio (SNR) by linear and non-linear mechanisms and thus help more accurately visualize the internal organs and [...] Read more.

Ultrasound Contrast Agents (UCAs) were developed to maximize reflection contrast so that organs can be seen clearly in ultrasound imaging. UCAs increase the signal to noise ratio (SNR) by linear and non-linear mechanisms and thus help more accurately visualize the internal organs and blood vessels. However, the UCAs on the market are not only expensive, but are also not optimized for use in various therapeutic research applications such as ultrasound-aided drug delivery. The UCAs fabricated in this study utilize conventional lipid and albumin for shell formation and perfluorobutane as the internal gas. The shape and density of the UCA bubbles were verified by optical microscopy and Cryo SEM, and compared to those of the commercially available UCAs, Definity^® and Sonovue^®. The size distribution and characteristics of the reflected signal were also analyzed using a particle size analyzer and ultrasound imaging equipment. Our experiments indicate that UCAs composed of spherical microbubbles, the majority of which were smaller than 1 um, were successfully synthesized. Microbubbles 10 um or larger were also identified when different shell characteristics and filters were used. These laboratory UCAs can be used for research in both diagnoses and therapies. Full article

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Open AccessArticle

Sesquiterpene Lactones and Their Derivatives Inhibit High Glucose-Induced NF-κB Activation and MCP-1 and TGF-β1 Expression in Rat Mesangial Cells

by Qian-Qian Jia, Jian-Cheng Wang, Jing Long, Yan Zhao, Si-Jia Chen, Jia-Dai Zhai, Lian-Bo Wei, Quan Zhang, Yue Chen and Hai-Bo Long

Molecules 2013, 18(10), 13061-13077; https://doi.org/10.3390/molecules181013061 - 21 Oct 2013

Cited by 54 | Viewed by 9889

Abstract

Diabetic nephropathy (DN) is one of the most common and serious chronic complications of diabetes mellitus, however, no efficient clinical drugs exist for the treatment of DN. We selected and synthesized several sesquiterpene lactones (SLs), and then used the MTT assay to detect [...] Read more.

Diabetic nephropathy (DN) is one of the most common and serious chronic complications of diabetes mellitus, however, no efficient clinical drugs exist for the treatment of DN. We selected and synthesized several sesquiterpene lactones (SLs), and then used the MTT assay to detect rat mesangial cells (MCs) proliferation, ELISA to measure the expression level of monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta (TGF-β1) and fibronectin(FN), real-time fluorescent quantitative PCR analysis to measure the MCP-1 and TGF-β1 gene expression, western blot to detect the level of IκBα protein and EMSA to measure the activation of nuclear factor kappa B (NF-κB). We discovered that SLs, including parthenolide (PTL), micheliolide (MCL), arglabin, and isoalantolactone (IAL), as well as several synthetic analogs of these molecules, could effectively attenuate the high glucose-stimulated activation of NF-κB, the degradation of IκBα, and the expression of MCP-1, TGF-β1 and FN in rat mesangial cells (MCs). These findings suggest that SLs and their derivatives have potential as candidate drugs for the treatment of DN. Full article

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Open AccessArticle

Synthesis and Structure-Activity Relationships of Amino Acid Conjugates of Cholanic Acid as Antagonists of the EphA2 Receptor

by Simonetta Russo, Matteo Incerti, Massimiliano Tognolini, Riccardo Castelli, Daniele Pala, Iftiin Hassan-Mohamed, Carmine Giorgio, Francesca De Franco, Antimo Gioiello, Paola Vicini, Elisabetta Barocelli, Silvia Rivara, Marco Mor and Alessio Lodola

Molecules 2013, 18(10), 13043-13060; https://doi.org/10.3390/molecules181013043 - 21 Oct 2013

Cited by 16 | Viewed by 6946

Abstract

The Eph–ephrin system plays a critical role in tumor growth and vascular functions during carcinogenesis. We had previously identified cholanic acid as a competitive and reversible EphA2 antagonist able to disrupt EphA2-ephrinA1 interaction and to inhibit EphA2 activation in prostate cancer cells. Herein, [...] Read more.

The Eph–ephrin system plays a critical role in tumor growth and vascular functions during carcinogenesis. We had previously identified cholanic acid as a competitive and reversible EphA2 antagonist able to disrupt EphA2-ephrinA1 interaction and to inhibit EphA2 activation in prostate cancer cells. Herein, we report the synthesis and biological evaluation of a set of cholanic acid derivatives obtained by conjugation of its carboxyl group with a panel of naturally occurring amino acids with the aim to improve EphA2 receptor inhibition. Structure-activity relationships indicate that conjugation of cholanic acid with linear amino acids of small size leads to effective EphA2 antagonists whereas the introduction of aromatic amino acids reduces the potency in displacement studies. The b-alanine derivative 4 was able to disrupt EphA2-ephrinA1 interaction in the micromolar range and to dose-dependently inhibit EphA2 activation on PC3 cells. These findings may help the design of novel EphA2 antagonists active on cancer cell lines. Full article

(This article belongs to the Special Issue Steroids)

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1356 KiB

Open AccessArticle

Synthesis and Protective Effect of New Ligustrazine-Benzoic Acid Derivatives against CoCl₂-Induced Neurotoxicity in Differentiated PC12 Cells

by Penglong Wang, Honggui Zhang, Fuhao Chu, Xin Xu, Jinxuan Lin, Chunxiao Chen, Guoliang Li, Yatao Cheng, Lin Wang, Qiang Li, Yuzhong Zhang and Haimin Lei

Molecules 2013, 18(10), 13027-13042; https://doi.org/10.3390/molecules181013027 - 18 Oct 2013

Cited by 25 | Viewed by 6853

Abstract

A series of novel ligustrazine-benzoic acid derivatives were synthesized and evaluated for their protective effect against cobalt chloride-induced neurotoxicity in differentiated PC12 cells. Combining hematoxylin and eosin staining, we found compound that (3,5,6-trimethylpyrazin-2-yl)methyl 3-methoxy-4-[(3,5,6-trimethylpyrazin-2-yl)methoxy]benzoate (4a) displayed promising protective effect on the [...] Read more.

A series of novel ligustrazine-benzoic acid derivatives were synthesized and evaluated for their protective effect against cobalt chloride-induced neurotoxicity in differentiated PC12 cells. Combining hematoxylin and eosin staining, we found compound that (3,5,6-trimethylpyrazin-2-yl)methyl 3-methoxy-4-[(3,5,6-trimethylpyrazin-2-yl)methoxy]benzoate (4a) displayed promising protective effect on the proliferation of the injured PC12 cells (EC₅₀ = 4.249 µM). Structure-activity relationships are brieﬂy discussed. Full article

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299 KiB

Open AccessArticle

Selection of a Mimotope Peptide of S-adenosyl-l-homocysteine and Its Application in Immunoassays

by Chun Wu and George Tzertzinis

Molecules 2013, 18(10), 13020-13026; https://doi.org/10.3390/molecules181013020 - 18 Oct 2013

Viewed by 5391

Abstract

A competitive immunoassay for S-adenosyl-l-homocysteine (SAH) has been used in the clinical test for homocysteine via an enzymatic conversion reaction. Since S-adenosyl-l-homocysteine is a relatively unstable compound, we have used peptide library phage display to select a new mimotope peptide that [...] Read more.

A competitive immunoassay for S-adenosyl-l-homocysteine (SAH) has been used in the clinical test for homocysteine via an enzymatic conversion reaction. Since S-adenosyl-l-homocysteine is a relatively unstable compound, we have used peptide library phage display to select a new mimotope peptide that interacts with the anti-SAH antibody. By immobilizing the synthetic peptide on solid phase as a competitive surrogate for SAH, we demonstrate its utility in a competitive ELISA assay. The linear range of the assay for SAH was 0.4–6.4 µM, in good correlation to the conventional assay using an SAH-conjugated plate. Our results show that the mimotope peptide has potential to substitute for SAH in immunoassays. Full article

(This article belongs to the Section Molecular Diversity)

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Open AccessArticle

Biological Activity of Oleanane Triterpene Derivatives Obtained by Chemical Derivatization

by Shi-Yie Cheng, Chao-Min Wang, Hsueh-Ling Cheng, Hui-Jye Chen, Yuan-Man Hsu, Yu-Chi Lin and Chang-Hung Chou

Molecules 2013, 18(10), 13003-13019; https://doi.org/10.3390/molecules181013003 - 18 Oct 2013

Cited by 16 | Viewed by 5883

Abstract

Nine new derivatives of oleanane triterpenoids isolated from Fatsia polycarpa Hayata were synthesized through chemical transformations. Acetylation was effected by reaction with acetic anhydride in pyridine to afford compounds 1–5, while compound 6 was obtained using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) in [...] Read more.

Nine new derivatives of oleanane triterpenoids isolated from Fatsia polycarpa Hayata were synthesized through chemical transformations. Acetylation was effected by reaction with acetic anhydride in pyridine to afford compounds 1–5, while compound 6 was obtained using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) in CH₂Cl₂. The others derivatives 7–9 were obtained in reactions of the corresponding triterpenoids with EDC·HCl, 4-N,N-dimethylaminopyridine hydrochloride and 4-N,N-dimethylaminopyridine in CH₂Cl₂. The structures of 1–9 were elucidated from extensive spectroscopic and HRESIMS data, while the structure of 9 was further confirmed by X-ray diffraction analysis. The cytotoxic, anti-hepatitis B virus (HBV), antibacterial, hypoglycaemic and Wnt signaling activities of these derivatives were evaluated in vitro. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

SOCS3-Mediated Blockade Reveals Major Contribution of JAK2/STAT5 Signaling Pathway to Lactation and Proliferation of Dairy Cow Mammary Epithelial Cells in Vitro

by Yu-Ling Huang, Feng Zhao, Chao-Chao Luo, Xia Zhang, Yu Si, Zhe Sun, Li Zhang, Qing-Zhang Li and Xue-Jun Gao

Molecules 2013, 18(10), 12987-13002; https://doi.org/10.3390/molecules181012987 - 17 Oct 2013

Cited by 52 | Viewed by 7412

Abstract

Suppressor of cytokine signaling 3 (SOCS3) is a cytokine-induced negative feedback-loop regulator of cytokine signaling. More and more evidence has proved it to be an inhibitor of signal transducers and activators of transcription 5 (STAT5). Here, we used dairy cow mammary epithelial cells [...] Read more.

Suppressor of cytokine signaling 3 (SOCS3) is a cytokine-induced negative feedback-loop regulator of cytokine signaling. More and more evidence has proved it to be an inhibitor of signal transducers and activators of transcription 5 (STAT5). Here, we used dairy cow mammary epithelial cells (DCMECs) to analyze the function of SOCS3 and the interaction between SOCS3 and STAT5a. The expression of SOCS3 was found in cytoplasm and nucleus of DCMECs by fluorescent immunostaining. Overexpression and inhibition of SOCS3 brought a remarkable milk protein synthesis change through the regulation of JAK2/STAT5a pathway activity, and SOCS3 expression also decreased SREBP-1c expression and fatty acid synthesis. Inhibited STAT5a activation correlated with reduced SOCS3 expression, which indicated that SOCS3 gene might be one of the targets of STAT5a activation, DCMECs treated with L-methionine (Met) resulted in a decrease of SOCS3 expression. SOCS3 could also decrease cell proliferation and viability by CASY-TT detection. Together, our findings indicate that SOCS3 acts as an inhibitor of JAK2/STAT5a pathway and disturbs fatty acid synthesis by decreasing SREBP-1c expression, which validates its involvement in both milk protein synthesis and fat synthesis. In aggregate, these results reveal that low SOCS3 expression is required for milk synthesis and proliferation of DCMECs in vitro. Full article

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Open AccessArticle

Endogenous Protection Derived from Activin A/Smads Transduction Loop Stimulated via Ischemic Injury in PC12 Cells

by Jing Mang, Chun-Li Mei, Jiao-Qi Wang, Zong-Shu Li, Ting-Ting Chu, Jin-Ting He and Zhong-Xin Xu

Molecules 2013, 18(10), 12977-12986; https://doi.org/10.3390/molecules181012977 - 17 Oct 2013

Cited by 14 | Viewed by 5212

Abstract

Activin A (ActA), a member of transforming growth factor-beta (TGF-b) super- family, affects many cellular processes, including ischemic stroke. Though the neuroprotective effects of exogenous ActA on oxygen-glucose deprivation (OGD) injury have already been reported by us, the endogenous role of ActA remains [...] Read more.

Activin A (ActA), a member of transforming growth factor-beta (TGF-b) super- family, affects many cellular processes, including ischemic stroke. Though the neuroprotective effects of exogenous ActA on oxygen-glucose deprivation (OGD) injury have already been reported by us, the endogenous role of ActA remains poorly understood. To further define the role and mechanism of endogenous ActA and its signaling in response to acute ischemic damage, we used an OGD model in PC12 cells to simulate ischemic injury on neurons in vitro. Cells were pre-treated by monoclonal antibody against activin receptor type IIA (ActRII-Ab). We found that ActRII-Ab augments ischemic injury in PC12 cells. Further, the extracellular secretion of ActA as well as phosphorylation of smad3 in PC12 cells was also up-regulated by OGD, but suppressed by ActRII-Ab. Taken together, our results show that ActRII-Ab may augment ischemic injury via blocking of transmembrane signal transduction of ActA, which confirmed the existence of endogenous neuroprotective effects derived from the ActA/Smads pathway. ActRIIA plays an important role in transferring neuronal protective signals inside. It is highly possible that ActA transmembrance signaling is a part of the positive feed-back loop for extracellular ActA secretion. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessCommunication

Oligonucleotide Labelling Using a Fluorogenic “Click” Reaction with a Hemicarboxonium Salt

by Marie-Pierre Maether, Kristie Lapin, Andreea Muntean, Corinne Payrastre and Jean-Marc Escudier

Molecules 2013, 18(10), 12966-12976; https://doi.org/10.3390/molecules181012966 - 17 Oct 2013

Viewed by 6427

Abstract

Two fluorescent streptocyanine labelled oligonucleotides have been synthesized by a simple “click” reaction between a non-fluorescent hemicarboxonium salt and aminoalkyl functionalized thymidines within the oligonucleotide and their spectrophotometric properties have been studied. Full article

(This article belongs to the Special Issue Synthesis of Nucleosides, Nucleotides and Their Derivatives)

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Open AccessArticle

Synthesis of Bistetrahydroquinolines as Potential Anticholinesterasic Agents by Double Diels-Alder Reactions

by Yorley Duarte, Margarita Gutiérrez, Luis Astudillo, Jans Alzate-Morales and Natalia Valdés

Molecules 2013, 18(10), 12951-12965; https://doi.org/10.3390/molecules181012951 - 17 Oct 2013

Cited by 8 | Viewed by 5985

Abstract

The tetrahydroquinoline ring system is a unit found in many biologically active natural products and pharmacologically relevant therapeutic agents. A new series of bistetrahydroquinolines (bis-THQs) was synthesized using imino Diels-Alder reactions between dialdehydes, anilines and N-vinyl-2-pyrrolidone (NVP). The notable features [...] Read more.

The tetrahydroquinoline ring system is a unit found in many biologically active natural products and pharmacologically relevant therapeutic agents. A new series of bistetrahydroquinolines (bis-THQs) was synthesized using imino Diels-Alder reactions between dialdehydes, anilines and N-vinyl-2-pyrrolidone (NVP). The notable features of this procedure are mild reaction conditions, greater selectivity and good yields of products. In addition, the inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of some selected derivatives is reported. The feasible binding modes of these active compounds, within AChE and BuChE binding sites, were predicted by molecular docking experiments and their binding affinity was estimated by means of free energy calculations through the MM-GBSA approximation. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessArticle

Antioxidant Activity and Anti-Adipogenic Effects of Wild Herbs Mainly Cultivated in Korea

by Young-Jun Lee, Dan-Bi Kim, Jong Seok Lee, Ju-Hyun Cho, Bong Kyun Kim, Hyeon-Son Choi, Boo-Yong Lee and Ok-Hwan Lee

Molecules 2013, 18(10), 12937-12950; https://doi.org/10.3390/molecules181012937 - 17 Oct 2013

Cited by 62 | Viewed by 9276

Abstract

Wild herbs, which are edible plants that grow in mountainous areas, have diverse biological effects such as anti-obesity and anti-cancer activities. The aim of this study was to evaluate the total phenolic and flavonoid contents as well as the antioxidant activity of methanol [...] Read more.

Wild herbs, which are edible plants that grow in mountainous areas, have diverse biological effects such as anti-obesity and anti-cancer activities. The aim of this study was to evaluate the total phenolic and flavonoid contents as well as the antioxidant activity of methanol extracts of Aster scaber, Ligularia fischeri, Kalopanax pictus, Codonopsis lanceolata, and Cirsium setidens and to assess their effects on lipid accumulation and reactive oxygen species (ROS) production during adipogenesis of 3T3-L1 cells. The results revealed that among the five studied wild herb extracts, Ligularia fischeri showed the highest total phenolic contents (215.8 ± 14.2 mg GAE/g) and Aster scaber showed the highest total flavonoid content (103.9 ± 3.4 mg RE/g). Furthermore, Aster scaber and Ligularia fischeri extracts showed higher antioxidant activity than the other wild herbs. Regarding anti-adipogenic activity, the Cirsium setidens extract significantly inhibited lipid accumulation (~80%) and ROS production (~50%) during adipogenesis of 3T3-L1 cells compared with control cells. These results suggest that wild herbs could be used for the development of functional foods as well as health promoting and pharmaceutical agents. Full article

(This article belongs to the Section Natural Products Chemistry)

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3446 KiB

Open AccessArticle

The Anti-Lung Cancer Activities of Steroidal Saponins of P. polyphylla Smith var. chinensis (Franch.) Hara through Enhanced Immunostimulation in Experimental Lewis Tumor-Bearing C57BL/6 Mice and Induction of Apoptosis in the A549 Cell Line

by Yu Li, Jun-Fei Gu, Xi Zou, Jian Wu, Ming-Hua Zhang, Jun Jiang, Dong Qin, Jin-Yong Zhou, Bao-Xin-Zi Liu, Yun-Tao Zhu, Xiao-Bin Jia, Liang Feng and Rui-Ping Wang

Molecules 2013, 18(10), 12916-12936; https://doi.org/10.3390/molecules181012916 - 17 Oct 2013

Cited by 49 | Viewed by 8435

Abstract

P. polyphylla Smith var. chinensis (Franch.) Hara (PPSCFH) has been used as medicinal Paris for the prevention and treatment of cancers in China for thousands of years. Its main components, steroidal saponins (PRS), have been confirmed to inhibit tumor growth. In the present [...] Read more.

P. polyphylla Smith var. chinensis (Franch.) Hara (PPSCFH) has been used as medicinal Paris for the prevention and treatment of cancers in China for thousands of years. Its main components, steroidal saponins (PRS), have been confirmed to inhibit tumor growth. In the present study, the immunostimulation of PRS was investigated in Lewis bearing-C57BL/6 mice while the induction of apoptosis in A549 cells was also studied. The treatment with PRS (2.5, 5.0 and 7.5 mg/kg) significantly inhibited tumor, volume, and weight in the C57BL/6 mice. The rates of inhibition of PRS (at 2.5, 5.0 and 7.5 mg/kg) were 26.49 ± 17.30%, 40.32 ± 18.91% and 54.94 ± 16.48%, respectively. The spleen and thymus indexes were increased remarkably, while the levels of inflammatory cytokines including TNF-α, IL-8 and IL-10 in serum were decreased according to ELISA assays. For A549 cells, Hoechst 33342 staining and annexin V/PI by flow cytometry showed that PRS (0.25, 0.50 and 0.75 mg/mL) induced nuclear changes of A549 cells with DNA condensation and fragmentations of chromatin, as well as inducing apoptosis. Furthermore, PRS could also attenuate the over-generation of intracellular ROS. Western blotting analysis showed a significant decrease on the expressions of proinflammatory cytokines MCP-1, IL-6 and TGF-β1, as well as cell adhesion molecule ICAM-1, by treatment with PRS. Our results demonstrated that the inhibition of PRS on tumor growth might be associated with the amelioration of inflammation responses, induction of apoptosis, as well as the decrease of ROS. These results suggested that PRS implied a potential therapeutic effect in the lung cancer treatment. Full article

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Open AccessArticle

Direct Light-up of cAMP Derivatives in Living Cells by Click Reactions

by Kenichiro Ito, Hongshan Liu, Makoto Komiyama, Tetsuya Hayashi and Yan Xu

Molecules 2013, 18(10), 12909-12915; https://doi.org/10.3390/molecules181012909 - 17 Oct 2013

Cited by 4 | Viewed by 5557

Abstract

8-Azidoadenosine 3′,5′-cyclic monophosphate (8-azido cAMP) was directly detected in living cells, by applying Cu-free azide-alkyne cycloaddition to probe cAMP derivatives by fluorescence light-up. Fluorescence emission was generated by two non-fluorescent molecules, 8-azido cAMP as a model target and difluorinated cyclooctyne (DIFO) reagent as [...] Read more.

8-Azidoadenosine 3′,5′-cyclic monophosphate (8-azido cAMP) was directly detected in living cells, by applying Cu-free azide-alkyne cycloaddition to probe cAMP derivatives by fluorescence light-up. Fluorescence emission was generated by two non-fluorescent molecules, 8-azido cAMP as a model target and difluorinated cyclooctyne (DIFO) reagent as a probe. The azide-alkyne cycloaddition reaction between 8-azido cAMP and DIFO induces fluorescence in 8-azido cAMP. The fluorescence emission serves as a way to probe 8-azido cAMP in cells. Full article

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Open AccessArticle

Preparative Separation of Spirobisnaphthalenes from Endophytic Fungus Berkleasmium sp. Dzf12 by High-Speed Counter-Current Chromatography

by Tijiang Shan, Shiqiong Lu, Chao Luo, Ruiya Luo, Yan Mou, Mingan Wang, Youliang Peng and Ligang Zhou

Molecules 2013, 18(10), 12896-12908; https://doi.org/10.3390/molecules181012896 - 16 Oct 2013

Cited by 8 | Viewed by 5485

Abstract

High-speed counter-current chromatography (HSCCC) was applied for the first time for the preparative separation of spirobisnaphthalenes from a crude extract of the endophytic fungus Berkleasmium sp. Dzf12, associated with the medicinal plant Dioscorea zingiberensis. Six spirobisnaphthalenes were successfully separated by HSCCC with [...] Read more.

High-speed counter-current chromatography (HSCCC) was applied for the first time for the preparative separation of spirobisnaphthalenes from a crude extract of the endophytic fungus Berkleasmium sp. Dzf12, associated with the medicinal plant Dioscorea zingiberensis. Six spirobisnaphthalenes were successfully separated by HSCCC with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (1.5:3.0:2.5:2.0, v/v). About 18.0 mg of diepoxin k (1), 245.7 mg of palmarumycin C₁₃ (2), 42.4 mg of palmarumycin C₁₆ (3), 42.2 mg of palmarumycin C₁₅ (4), 32.6 mg of diepoxin δ (5), and 22.3 mg of diepoxin γ (6) with purities of 56.82, 71.39, 76.57, 75.86, 91.01 and 82.48%, respectively, as determined by high-performance liquid chromatography (HPLC), were obtained from 500 mg of the crude extract in a one-step elution within 7 h of separation procedure by HSCCC. The purified spirobisnaphthalenes were further structurally characterized by means of physicochemical and spectrometric analysis. Full article

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Open AccessArticle

Elicitation of Induced Resistance against Pectobacterium carotovorum and Pseudomonas syringae by Specific Individual Compounds Derived from Native Korean Plant Species

by Geun Cheol Song, Shi Yong Ryu, Young Sup Kim, Ji Young Lee, Jung Sup Choi and Choong-Min Ryu

Molecules 2013, 18(10), 12877-12895; https://doi.org/10.3390/molecules181012877 - 16 Oct 2013

Cited by 22 | Viewed by 7820

Abstract

Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species [...] Read more.

Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species to determine whether they triggered induced resistance against Pectobacterium carotovorum supsp. carotovorum (Pcc) in tobacco (Nicotiana tabacum) and Pseudomonas syringae pv. tomato (Pst) in Arabidopsis thaliana. To select target compound(s) with direct and indirect (volatile) effects, a new Petri-dish-based in vitro disease assay system with four compartments was developed. The screening assay showed that capsaicin, fisetin hydrate, jaceosidin, and farnesiferol A reduced the disease severity significantly in tobacco. Of these four compounds, capsaicin and jaceosidin induced resistance against Pcc and Pst, which depended on both salicylic acid (SA) and jasmonic acid (JA) signaling, using Arabidopsis transgenic and mutant lines, including npr1 and NahG for SA signaling and jar1 for JA signaling. The upregulation of the PR2 and PDF1.2 genes after Pst challenge with capsaicin pre-treatment indicated that SA and JA signaling were primed. These results demonstrate that capsaicin and jaceosidin can be effective triggers of strong induced resistance against both necrotrophic and biotrophic plant pathogens. Full article

(This article belongs to the Section Natural Products Chemistry)

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Open AccessArticle

Chemometric Evaluation of Urinary Steroid Hormone Levels as Potential Biomarkers of Neuroendocrine Tumors

by Alina Plenis, Natalia Miękus, Ilona Olędzka, Tomasz Bączek, Anna Lewczuk, Zofia Woźniak, Patrycja Koszałka, Barbara Seroczyńska and Jarosław Skokowski

Molecules 2013, 18(10), 12857-12876; https://doi.org/10.3390/molecules181012857 - 16 Oct 2013

Cited by 7 | Viewed by 6301

Abstract

Neuroendocrine tumors (NETs) are uncommon tumors which can secrete specific hormone products such as peptides, biogenic amines and hormones. So far, the diagnosis of NETs has been difficult because most NET markers are not specific for a given tumor and none of the [...] Read more.

Neuroendocrine tumors (NETs) are uncommon tumors which can secrete specific hormone products such as peptides, biogenic amines and hormones. So far, the diagnosis of NETs has been difficult because most NET markers are not specific for a given tumor and none of the NET markers can be used to fulfil the criteria of high specificity and high sensitivity for the screening procedure. However, by combining the measurements of different NET markers, they become highly sensitive and specific diagnostic tests. The aim of the work was to identify whether urinary steroid hormones can be identified as potential new biomarkers of NETs, which could be used as prognostic and clinical course monitoring factors. Thus, a rapid and sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) with UV detection has been developed for the determination of cortisol, cortisone, corticosterone, testosterone, epitestosterone and progesterone in human urine. The method has been validated for accuracy, precision, selectivity, linearity, recovery and stability. The limits of detection and quantification were 0.5 and 1 ng mL⁻¹ for each steroid hormone, respectively. Linearity was confirmed within a range of 1–300 ng mL⁻¹ with a correlation coefficient greater than 0.9995 for all analytes. The described method was successfully applied for the quantification of six endogenous steroid levels in human urine. Studies were performed on 20 healthy volunteers and 19 patients with NETs. Next, for better understanding of tumor biology in NETs and for checking whether steroid hormones can be used as potential biomarkers of NETs, a chemometric analysis of urinary steroid hormone levels in both data sets was performed. Full article

(This article belongs to the Special Issue Steroids)

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Cs⁺ Removal from Aqueous Solutions through Adsorption onto Florisil^® Impregnated with Trihexyl(tetradecyl)phosphonium Chloride

by Lavinia Lupa, Adina Negrea, Mihaela Ciopec and Petru Negrea

Molecules 2013, 18(10), 12845-12856; https://doi.org/10.3390/molecules181012845 - 16 Oct 2013

Cited by 24 | Viewed by 6194

Abstract

This research determined the adsorption performance of Florisil^® impregnated with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101) in the process of Cs⁺ removal from aqueous solutions. The obtained Florisil^® impregnated with the studied ionic liquid was characterized through energy dispersive X-ray analysis and [...] Read more.

This research determined the adsorption performance of Florisil^® impregnated with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101) in the process of Cs⁺ removal from aqueous solutions. The obtained Florisil^® impregnated with the studied ionic liquid was characterized through energy dispersive X-ray analysis and Fourier transform infrared spectroscopy in order to verify that the impregnation with the ionic liquid had occurred. The adsorption process has been investigated as a function of pH, solid:liquid ratio, adsorbate concentration, contact time and temperature. The isotherm data was well described by a Langmuir isotherm model. The maximum adsorption capacities of the Florisil^® impregnated with the studied ionic liquid was found to be 3.086 mg Cs⁺/g of adsorbent. The results indicated that the adsorption fitted well with the pseudo-second order kinetic model. Full article

(This article belongs to the Special Issue Organophosphorus Chemistry)

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Synthesis of Cycloveratrylene Macrocycles and Benzyl Oligomers Catalysed by Bentonite under Microwave/Infrared and Solvent-Free Conditions

by René Miranda, Omar Valencia-Vázquez, Carlos Abel Maya-Vega, Inés Nicolás-Vázquez, Yolanda Marina Vargas-Rodriguez, José Antonio Morales-Serna, Eréndira García-Ríos and Manuel Salmón

Molecules 2013, 18(10), 12820-12844; https://doi.org/10.3390/molecules181012820 - 16 Oct 2013

Cited by 5 | Viewed by 6596

Abstract

Tonsil Actisil FF, which is a commercial bentonitic clay, promotes the formation of cycloveratrylene macrocycles and benzyl oligomers from the corresponding benzyl alcohols in good yields under microwave heating and infrared irradiation in the absence of solvent in both cases. The catalytic reaction [...] Read more.

Tonsil Actisil FF, which is a commercial bentonitic clay, promotes the formation of cycloveratrylene macrocycles and benzyl oligomers from the corresponding benzyl alcohols in good yields under microwave heating and infrared irradiation in the absence of solvent in both cases. The catalytic reaction is sensitive to the type of substituent on the aromatic ring. Thus, when benzyl alcohol was substituted with a methylenedioxy, two methoxy or three methoxy groups, a cyclooligomerisation process was induced. Unsubstituted, methyl and methoxy benzyl alcohols yielded linear oligomers. In addition, computational chemistry calculations were performed to establish a validated mechanistic pathway to explain the growth of the obtained linear oligomers. Full article

(This article belongs to the Section Organic Chemistry)

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Open AccessArticle

Astragaloside IV Stimulates Angiogenesis and Increases Nitric Oxide Accumulation via JAK2/STAT3 and ERK1/2 Pathway

by Shi-Guang Wang, Yan Xu, Jian-Dong Chen, Chuan-Hua Yang and Xiao-Hu Chen

Molecules 2013, 18(10), 12809-12819; https://doi.org/10.3390/molecules181012809 - 16 Oct 2013

Cited by 66 | Viewed by 7802

Abstract

Astragaloside IV (AS-IV), one of the major active constituents of Astragalus membranaceus in Traditional Chinese Medicine, has been widely used to treat ischemic diseases. However, the potential mechanism is this action is unclear. In this study, we tested the hypothesis that AS-IV might [...] Read more.

Astragaloside IV (AS-IV), one of the major active constituents of Astragalus membranaceus in Traditional Chinese Medicine, has been widely used to treat ischemic diseases. However, the potential mechanism is this action is unclear. In this study, we tested the hypothesis that AS-IV might promote angiogenesis through multiple signaling pathways. Our data indicate that AS-IV treatment promotes umbilical vein endothelial cells (HUVEC) proliferation, migration, and tube formation. AS-IV treatment also activates JAK2/STAT3 and ERK1/2 signaling pathways, and up-regulates endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production. AS-IV-induced angiogenesis in HUVECs is significantly blocked by specific kinase inhibitors. Our study indicated that AS-IV is a key regulator of NO and angiogenesis through the JAK2/STAT3 and ERK1/2 pathways, which provides a mechanistic basis for the potential use of this compound in the treatment of clinical ischemic diseases. Full article

(This article belongs to the Section Natural Products Chemistry)

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Apoptosis Sensitization by Euphorbia Factor L1 in ABCB1-Mediated Multidrug Resistant K562/ADR Cells

by Jian-Ye Zhang, Min-Ting Lin, Tao Yi, Yi-Na Tang, Lan-Lan Fan, Xi-Cheng He, Zhong-Zhen Zhao and Hu-Biao Chen

Molecules 2013, 18(10), 12793-12808; https://doi.org/10.3390/molecules181012793 - 16 Oct 2013

Cited by 27 | Viewed by 6711

Abstract

In this article, reversal activities of Euphorbia factor L1 (EFL1) against ABCB1-mediated multidrug resistance (MDR) and apoptosis sensitization in K562/ADR cells are reported. EFL1 decreased the IC₅₀ values of anticancer agents in K562/ADR cells over-expressing ABCB1. However, EFL1 did not affect the [...] Read more.

In this article, reversal activities of Euphorbia factor L1 (EFL1) against ABCB1-mediated multidrug resistance (MDR) and apoptosis sensitization in K562/ADR cells are reported. EFL1 decreased the IC₅₀ values of anticancer agents in K562/ADR cells over-expressing ABCB1. However, EFL1 did not affect the IC₅₀ values of anticancer agents in sensitive K562 cells. Additionally, EFL1 increased the intracellular accumulation of rhodamine 123 and doxorubicin in K562/ADR cells without affecting their accumulation in K562 cells. Furthermore, EFL1 sensitized the apoptosis triggered by vincristine in K562/ADR cells via mitochondrial pathway, as confirmed by Annexin V-FITC/PI detection and western blot. At the same time, EFL1 did not influence the apoptosis induced by vincristine in K562 cells. Western blot results showed that EFL1 did not affect the phosphorylation level of AKT and ERK in K562 and K562/ADR cells. Finally, EFL1 did not down-regulate protein expression of ABCB1. Full article

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Ginsenoside Rb1 Attenuates Oxygen-Glucose Deprivation-Induced Apoptosis in SH-SY5Y Cells via Protection of Mitochondria and Inhibition of AIF and Cytochrome c Release

by Jianmin Liang, Ying Yu, Boyu Wang, Bin Lu, Jizhou Zhang, Hongbo Zhang and Pengfei Ge

Molecules 2013, 18(10), 12777-12792; https://doi.org/10.3390/molecules181012777 - 16 Oct 2013

Cited by 52 | Viewed by 9533

Abstract

To investigate the role of mitochondria in the protective effects of ginsenoside Rb1 on cellular apoptosis caused by oxygen-glucose deprivation, in this study, MTT assay, TUNEL staining, flow cytometry, immunocytochemistry and western blotting were used to examine the cellular viability, apoptosis, ROS level, [...] Read more.

To investigate the role of mitochondria in the protective effects of ginsenoside Rb1 on cellular apoptosis caused by oxygen-glucose deprivation, in this study, MTT assay, TUNEL staining, flow cytometry, immunocytochemistry and western blotting were used to examine the cellular viability, apoptosis, ROS level, mitochondrial membrane potential, and the distribution of apoptosis inducing factor, cytochrome c, Bax and Bcl-2 in nucleus, mitochondria and cytoplasm. We found that pretreatment with GRb1 improved the cellular viability damaged by OGD. Moreover, GRb1 inhibited apoptosis in SH-SY5Y cells induced by OGD. Further studies showed that the elevation of cellular reactive oxygen species levels and the reduction of mitochondrial membrane potential caused by OGD were both counteracted by GRb1. Additionally, GRb1 not only suppressed the translocation of apoptosis inducing factor into nucleus and cytochrome c into cytoplasm, but also inhibited the increase of Bax within mitochondria and alleviated the decrease of mitochondrial Bcl-2. Our study indicates that the protection of GRb1 on OGD-induced apoptosis in SH-SY5Y cells is associated with its protection on mitochondrial function and inhibition of release of AIF and cytochrome c. Full article

(This article belongs to the Section Natural Products Chemistry)

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Ring-Opening Polymerization of l-Lactic Acid O-Carboxyanhydrides Initiated by Alkoxy Rare Earth Compounds

by Zhengguo He, Lin Jiang, Yongming Chuan, Hongli Li and Minglong Yuan

Molecules 2013, 18(10), 12768-12776; https://doi.org/10.3390/molecules181012768 - 15 Oct 2013

Cited by 21 | Viewed by 7055

Abstract

The ring-opening polymerization of l-lactic acid O-carboxyanhydrides was initiated by triisopropoxyneodymium in toluene-THF mixtures. Typically, high yields and relatively high molecular weight PLAs were obtained within 4 h at 25 °C. The reaction was highly controllable and easy to conduct, and the [...] Read more.

The ring-opening polymerization of l-lactic acid O-carboxyanhydrides was initiated by triisopropoxyneodymium in toluene-THF mixtures. Typically, high yields and relatively high molecular weight PLAs were obtained within 4 h at 25 °C. The reaction was highly controllable and easy to conduct, and the molecular weight distribution of the PLAs was rather narrow (Mw/Mn = 1.10–1.36). NMR analysis showed that one end of the PLA chain consisted of an isopropoxy group, while the other end of the chain contained a hydroxyl group. Due to their availability and high polymerizability, Lac-OCAs are promising monomers for the preparation of tailored architectures derived from well-defined PLAs. Full article

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The Effect of Molecular Crowding on the Stability of Human c-MYC Promoter Sequence I-Motif at Neutral pH

by Jingjing Cui, Phillip Waltman, Vu H. Le and Edwin A. Lewis

Molecules 2013, 18(10), 12751-12767; https://doi.org/10.3390/molecules181012751 - 15 Oct 2013

Cited by 93 | Viewed by 10690

Abstract

We have previously shown that c-MYC promoter sequences can form stable i-motifs in acidic solution (pH 4.5–5.5). In terms of drug targeting, the question is whether c-MYC promoter sequence i-motifs will exist in the nucleus at neutral pH. In this work, we have [...] Read more.

We have previously shown that c-MYC promoter sequences can form stable i-motifs in acidic solution (pH 4.5–5.5). In terms of drug targeting, the question is whether c-MYC promoter sequence i-motifs will exist in the nucleus at neutral pH. In this work, we have investigated the stability of a mutant c-MYC i-motif in solutions containing a molecular crowding agent. The crowded nuclear environment was modeled by the addition of up to 40% w/w polyethylene glycols having molecular weights up to 12,000 g/mol. CD and DSC were used to establish the presence and stability of c-MYC i-motifs in buffer solutions over the pH range 4 to 7. We have shown that the c-MYC i-motif can exist as a stable structure at pH values as high as 6.7 in crowded solutions. Generic dielectric constant effects, e.g., a shift in the pKa of cytosine by more than 2 units (e.g., 4.8 to 7.0), or the formation of non-specific PEG/DNA complexes appear to contribute insignificantly to i-motif stabilization. Molecular crowding, largely an excluded volume effect of added PEG, having a molecular weight in excess of 1,000 g/mol, appears to be responsible for stabilizing the more compact i-motif over the random coil at higher pH values. Full article

(This article belongs to the Special Issue G-Quadruplexes & i-Motif DNA)

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An Efficient and Facile Methodology for Bromination of Pyrimidine and Purine Nucleosides with Sodium Monobromoisocyanurate (SMBI)

by Jyotirmoy Maity and Roger Stromberg

Molecules 2013, 18(10), 12740-12750; https://doi.org/10.3390/molecules181012740 - 15 Oct 2013

Cited by 8 | Viewed by 7476

Abstract

An efficient and facile strategy has been developed for bromination of nucleosides using sodium monobromoisocyanurate (SMBI). Our methodology demonstrates bromination at the C-5 position of pyrimidine nucleosides and the C-8 position of purine nucleosides. Unprotected and also several protected nucleosides were brominated in [...] Read more.

An efficient and facile strategy has been developed for bromination of nucleosides using sodium monobromoisocyanurate (SMBI). Our methodology demonstrates bromination at the C-5 position of pyrimidine nucleosides and the C-8 position of purine nucleosides. Unprotected and also several protected nucleosides were brominated in moderate to high yields following this procedure. Full article

(This article belongs to the Special Issue Synthesis of Nucleosides, Nucleotides and Their Derivatives)

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Microwave Assisted Synthesis, Antifungal Activity and DFT Theoretical Study of Some Novel 1,2,4-Triazole Derivatives Containing the 1,2,3-Thiadiazole Moiety

by Na-Bo Sun, Jian-Qun Fu, Jian-Quan Weng, Jian-Zhong Jin, Cheng-Xia Tan and Xing-Hai Liu

Molecules 2013, 18(10), 12725-12739; https://doi.org/10.3390/molecules181012725 - 15 Oct 2013

Cited by 74 | Viewed by 7424

Abstract

In order to investigate the biological activity of 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing 1,2,3-thiadiazole moieties were synthesized by multi-step reactions under microwave assisted conditions. The structures were characterized by ¹H-NMR, ¹³C-NMR, MS and elemental analyses. The target compounds [...] Read more.

In order to investigate the biological activity of 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing 1,2,3-thiadiazole moieties were synthesized by multi-step reactions under microwave assisted conditions. The structures were characterized by ¹H-NMR, ¹³C-NMR, MS and elemental analyses. The target compounds were evaluated for their in vivo fungicidal activities against Corynespora cassiicola, Pseudomonas syringae pv. Lachrymans, and Pseudoperonospora cubensis, and the results indicated that some of the title compounds displayed good fungicidal activities. Theoretical calculations on the title compounds were carried out at the B3LYP/6-31G (d,p). level. The full geometry optimization was carried out using the 6-31G(d,p) basis set, and the frontier orbital energy, atomic net charges were discussed, and the structure-activity relationships were also studied. Full article

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Heteroaryl Chalcones: Design, Synthesis, X-ray Crystal Structures and Biological Evaluation

by C. S. Chidan Kumar, Wan-Sin Loh, Chin Wei Ooi, Ching Kheng Quah and Hoong-Kun Fun

Molecules 2013, 18(10), 12707-12724; https://doi.org/10.3390/molecules181012707 - 15 Oct 2013

Cited by 45 | Viewed by 7866

Abstract

Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen [...] Read more.

Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a–i) containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series. Full article

(This article belongs to the Section Molecular Diversity)

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Orbital Interaction and Electron Density Transfer in Pd^II([9]aneB₂A)L₂ Complexes: Theoretical Approaches

by Ock Keum Kwak, Mahreen Arooj, Yong-Jin Yoon, Euh Duck Jeong and Jong Keun Park

Molecules 2013, 18(10), 12687-12706; https://doi.org/10.3390/molecules181012687 - 14 Oct 2013

Cited by 1 | Viewed by 7847

Abstract

The geometric structures of Pd-complexes {Pd([9]aneB₂A)L₂ and Pd([9]aneBAB)L₂ where A = P, S; B = N; L = PH₃, P(CH₃)₃, Cl⁻}, their selective orbital interaction [...] Read more.

The geometric structures of Pd-complexes {Pd([9]aneB₂A)L₂ and Pd([9]aneBAB)L₂ where A = P, S; B = N; L = PH₃, P(CH₃)₃, Cl⁻}, their selective orbital interaction towards equatorial or axial (soft A…Pd) coordination of macrocyclic [9]aneB₂A tridentate to PdL₂, and electron density transfer from the electron-rich trans L-ligand to the low-lying unfilled a_1g(5s)-orbital of PdL₂ were investigated using B3P86/lanl2DZ for Pd and 6-311+G** for other atoms. The pentacoordinate endo-[Pd([9]aneB₂A)(L-donor)₂]²⁺ complex with an axial (soft A--Pd) quasi-bond was optimized for stability. The fifth (soft A--Pd) quasi-bond between the σ-donor of soft A and the partially unfilled a_1g(5s)-orbital of PdL₂ was formed. The pentacoordinate endo-Pd([9]aneB₂A)(L-donor)₂]²⁺ complex has been found to be more stable than the corresponding tetracoordinate endo-Pd complexes. Except for the endo-Pd pentacoordinates, the tetracoordinate Pd([9]aneBAB)L₂ complex with one equatorial (soft A-Pd) bond is found to be more stable than the Pd([9]aneB₂A)L₂ isomer without the equatorial (A-Pd) bond. In particular, the geometric configuration of endo-[Pd([9]anePNP)(L-donor)₂]²⁺ could not be optimized. Full article

(This article belongs to the Special Issue Macrocyclic Chemistry)

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Electrochemical Enzyme-Linked Immunosorbent Assay (ELISA) for α-Fetoprotein Based on Glucose Detection with Multienzyme-Nanoparticle Amplification

by Qin-Lan Liu, Xiao-Hui Yan, Xiao-Mao Yin, Bo Situ, Han-Kun Zhou, Li Lin, Bo Li, Ning Gan and Lei Zheng

Molecules 2013, 18(10), 12675-12686; https://doi.org/10.3390/molecules181012675 - 14 Oct 2013

Cited by 44 | Viewed by 9317

Abstract

Since glucose biosensors are one of the most popular and widely used point-of-care testing devices, a novel electrochemical enzyme-linked immunosorbent assay (ELISA) for protein biomarkers has been developed based on a glucose detection strategy. In this study, α-fetoprotein (AFP) was used as the [...] Read more.

Since glucose biosensors are one of the most popular and widely used point-of-care testing devices, a novel electrochemical enzyme-linked immunosorbent assay (ELISA) for protein biomarkers has been developed based on a glucose detection strategy. In this study, α-fetoprotein (AFP) was used as the target protein. An electrochemical ELISA system was constructed using anti-AFP antibodies immobilized on microwell plates as the capture antibody (Ab₁) and multi-label bioconjugates as signal tracer. The bioconjugates were synthesized by attaching glucoamylase and the secondary anti-AFP antibodies (Ab₂) to gold nanoparticles (AuNPs). After formation of the sandwich complex, the Ab₂-glucoamylase-AuNPs conjugates converted starch into glucose in the presence of AFP. The concentration of AFP can be calculated based on the linear relation between AFP and glucose, the concentration of which can be detected by the glucose biosensor. When the AFP concentration ranged from 0.05 to 100 ng/mL, a linear calibration plot (i (µA) = 13.62033 − 2.86252 logCAFP (ng/mL), r = 0.99886) with a detection limit of 0.02 ng/mL was obtained under optimal conditions. The electrochemical ELISA developed in this work shows acceptable stability and reproducibility, and the assay for AFP spiked in human serum also shows good recovery (97.0%–104%). This new method could be applied for detecting any protein biomarker with the corresponding antibodies. Full article

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Molecules, Volume 18, Issue 10 (October 2013) – 92 articles , Pages 11658-13123

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