Identifying the acidic or basic behavior of surface water: a QM/MM-MD study.

Controversies on the water surface were theoretically addressed with the help of large scale quantum mechanical molecular dynamics (QMMD) simulations on water surface model systems with and without excess hydroniums and hydroxides. It was revealed that the thermodynamic surface structures of these ions strongly depend on their location and dipole orientation. Fast hydronium diffusion by proton transfer establishes a wider kinetic depth distribution (∼6 Å) than that predicted by its thermodynamic affinity for the water surface, while slow hydroxide is shallowly trapped below the outermost molecular layer (3-4 Å). In addition, the anisotropic orientation of surface water dipole can generate a substantial magnitude of surface potential, which extends to a depth of a few molecular layers. With these distinctively different surface properties of two ions and water molecules, the seemingly contradictory observations of acidic and negatively charged water surfaces may be successfully explained. That is, the negative surface charge of neutral water mostly stems from intrinsic water properties such as water dipole orientation and electron density spillage at the surface, rather than surface OH- ions. The enhanced acidity of the water surface can be attributed in large part to the kinetic depth profile of ion density in addition to static thermodynamic origin. Furthermore, the different depth profiles of the two ions may differently affect the surface-sensitive spectroscopic observations.

Evaluation and docking of indole sulfonamide as a potent inhibitor of α-glucosidase enzyme in streptozotocin -induced diabetic albino wistar rats.

We have synthesized new hybrid class of indole bearing sulfonamide scaffolds (1-17) as α-glucosidase inhibitors. All scaffolds were found to be active except scaffold 17 and exhibited IC50 values ranging from 1.60 to 51.20 µM in comparison with standard acarbose (IC50 = 42.45 µM). Among the synthesized hybrid class scaffolds 16 was the most potent analogue with IC50 value 1.60 µM, showing many folds better potency as compared to standard acarbose. Whereas, synthesized scaffolds 1-15 showed good α-glucosidase inhibitory potential. Based on α-glucosidase inhibitory effect, Scaffold 16 was chosen due to highest activity in vitro for further evaluation of antidiabetic activity in Streptozotocin induced diabetic rats. The Scaffold 16 exhibited significant antidiabetic activity. All analogues were characterized through 1H, 13CNMR and HR MS. Structure-activity relationship of synthesized analogues was established and confirmed through molecular docking study.

Synthesis of indole-based-thiadiazole derivatives as a potent inhibitor of α-glucosidase enzyme along with in silico study.

A series of nineteen (1-19) indole-based-thiadiazole derivatives were synthesized, characterized by 1HNMR, 13C NMR, MS, and screened for α-glucosidase inhibition. All analogs showed varied α-glucosidase inhibitory potential with IC50 value ranged between 0.95 ± 0.05 to 13.60 ± 0.30 µM, when compared with the standard acarbose (IC50 = 1.70 ± 0.10). Analogs 17, 2, 1, 9, 7, 3, 15, 10, 16, and 14 with IC50 values 0.95 ± 0.05, 1.10 ± 0.10, 1.30 ± 0.10, 1.60 ± 0.10, 2.30 ± 0.10, 2.30 ± 0.10, 2.80 ± 0.10, 4.10 ± 0.20 and 4.80 ± 0.20 µM respectively showed highest α-glucosidase inhibition. All other analogs also exhibit excellent inhibitory potential. Structure activity relationships have been established for all compounds primarily based on substitution pattern on the phenyl ring. Through molecular docking study, binding interactions of the most active compounds were confirmed. We further studied the kinetics study of analogs 1, 2, 9 and 17 and found that they are Non-competitive inhibitors.

Application of silver-assisted laser desorption ionization ultrahigh-resolution mass spectrometry for the speciation of sulfur compounds.

We herein report the optimization and application of silver cationization (Ag+) in combination with laser desorption ionization (LDI) ultrahigh-resolution mass spectrometry (UHR-MS) to determine the structures of the sulfur-containing compounds present in heavy crude oil. A number of sulfur-containing model compounds were used to optimize the positive-ion mode LDI-MS conditions in the presence of a silver-complexing agent. Under the optimized LDI conditions, sulfur-rich heavy oil fractions were treated with the silver salt, where Ag+ coordinated with the sulfur atoms to speciate the sulfur species. The obtained results suggested that benzothiophenic, naphtheno-non-aromatic sulfides, and non-aromatic thiols were the major components present in the analyzed oil sample. Graphical abstract.

Synthesis, α-glycosidase inhibitory potential and molecular docking study of benzimidazole derivatives.

A series of twenty-six analogs of benzimidazole based oxadiazole have been synthesized and evaluated against alpha-glycosidase enzyme. Most the analogs showed excellent to good inhibitory potential. Among the screened analogs, analog 1, 2, 3 and 14 with IC50 values 4.6 ± 0.1, 9.50 ± 0.3, 2.6 ± 0.1 and 9.30 ± 0.4 µM respectively showedexcellent inhibitory potential than reference drug acarbose (IC50 = 38.45 ± 0.80 µM). Some of the analogs like 19, 21, 22 and 23 with methyl and methoxy substituent on phenyl ring show hydrophobic interaction and were found with no inhibitory potential. The binding interactions between synthesized analogs and ligands protein were confirmed through molecular docking study. Various spectroscopic techniques like 1H NMR, 13C NMR, and EI-MS were used for characterization of all synthesized analogs. These derivatives were synthesized by simple mode of synthesis like heterocyclic ring formation.

Synthesis, in vitro alpha-glucosidase inhibitory potential of benzimidazole bearing bis-Schiff bases and their molecular docking study.

Voglibose and acarbose are distinguished α-glucosidase inhibitors used for controlling of diabetes mellitus. Unfortunately, these distinguished and clinically used inhibitors have also numerous side effects. Subsequently, there is still needed to develop safer therapy. Despite of a broad spectrum of biological importance of benzimidazole, it is occasionally evaluated for α-glucosidase activity. Current study deals with the synthesis and biological screening of benzimidazole bearing bis-Schiff bases (1-19) for their α-glucosidase inhibitory activity. All analogues exhibited excellent to good inhibitory potential (IC50 = 2.20 ±â€¯0.1to 88.60 ±â€¯1.70 µM) when compared with standard drug acarbose (IC50 = 38.45 ±â€¯0.80 µM). A structure activity relationship has been established on the basis of electronic effects and position of different substituents present on phenyl ring. In order to rationalize the binding interactions of most active analogues with the active site of α-glucosidase enzyme, molecular docking study was conducted.

Synthesis of indole based acetohydrazide analogs: Their in vitro and in silico thymidine phosphorylase studies.

In this study, a series of indole based acetohydrazide derivatives (1-22) were synthesized and characterized by 13C NMR, 1H NMR and HREI-MS. The resulted derivatives were tested for thymidine phosphorylase inhibitory potential. These derivatives inhibited thymidine phosphorylase at different concentration ranging from 1.10 ± 0.10 to 41.10 ± 1.10 µM when compared with the standard 7-Deazaxanthine (IC50 value 38.68 ± 1.12 µM). The compound 8 having OH group at 2, 4 and 6 position was found the most potent among the series with IC50 1.10 ± 0.10 µM. The structure activity relationships (SAR) has been established for all compounds keeping in the view the role of substitution and the effect of functional group which significantly affect thymidine phosphorylase activity. The nature of binding interactions of the most potent compounds and active sites of the enzymes was confirmed through molecular docking study.

Synthesis of Benzimidazole-Based Analogs as Anti Alzheimer's Disease Compounds and Their Molecular Docking Studies.

We synthesized 10 analogs of benzimidazole-based thiosemicarbazide 1 (a-j) and 13 benzimidazole-based Schiff bases 2 (a-m), and characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase (AchE) and butyrylcholinesterase (BchE) inhibition activities. All the synthesized analogs showed varying degrees of acetylcholinesterase and butyrylcholinesterase inhibitory potentials in comparison to the standard drug (IC50 = 0.016 and 4.5 µM. Amongst these analogs 1 (a-j), compounds 1b, 1c, and 1g having IC50 values 1.30, 0.60, and 2.40 µM, respectively, showed good acetylcholinesterase inhibition when compared with the standard. These compounds also showed moderate butyrylcholinesterase inhibition having IC50 values of 2.40, 1.50, and 2.40 µM, respectively. The rest of the compounds of this series also showed moderate to weak inhibition. While amongst the second series of analogs 2 (a-m), compounds 2c, 2e, and 2h having IC50 values of 1.50, 0.60, and 0.90 µM, respectively, showed moderate acetylcholinesterase inhibition when compared to donepezil. Structure Aactivity Relation of both synthesized series has been carried out. The binding interactions between the synthesized analogs and the enzymes were identified through molecular docking simulations.

Hepatoprotective and Antioxidant Activities of Justicia gendarussa Leaf Extract in Carbofuran-Induced Hepatic Damage in Rats.

In folk medicines, Justicia gendarussa (J. gendarussa) is used as a depurative herb for treating fever, pain, and cancer and as laxative for constipation. The aim of the present investigation was to evaluate the hepatoprotective effect of the leaf methanol extract of J. gendarussa leaf (J gMe) against carbofuran (CF)-intoxicated liver injuries in Sprague-Dawley rats, along with the antioxidant activity of this extract. For this purpose, levels of serum diagnostic markers, hepatic antioxidant enzymes, and liver histo-architecture were employed to justify the protective efficacy of J gMe. In addition, the phenolic and flavonoid contents of the extract were quantified, and antioxidant activity was investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide, hydrogen peroxide, and hydroxyl free radical scavenging assays. Results revealed that the leaf extract caused a significant (<0.05, <0.01) decrease of the level of hepatic enzymes, triglycerides, and bilirubin and an increase of the total protein. J gMe has also significantly (<0.05, <0.01) lowered the level of malonylaldehyde. Carbofuran markedly suppressed hepatic antioxidant enzymes, however, the leaf extract significantly augmented these enzymes. The hepatoprotective effect was demonstrated by the improvement in the histo-architectural features of liver sections of CF-intoxicated rats treated with J gMe at 500 mg/kg dose. In addition, J gMe showed moderate total phenolic and total flavonoid content, whereas the IC50 values of DPPH, nitric oxide, hydrogen peroxide, and hydroxyl free radical scavenging assays were 71.31 ± 0.42, 134.82 ± 0.14, 47.69 ± 0.38, and 118.44 ± 0.30 µg/mL, respectively. In conclusion, the present study suggests the protective role of J gMe against hepatic injury induced by CF, which may be attributed to its higher antioxidant properties and thereby scientifically justifies its traditional use.

Synthesis of quinoline derivatives as diabetic II inhibitors and molecular docking studies.

In searchof the potenttherapeutic agent as an α-glucosidase inhibitor, we have synthesized twenty-five analogs (1-25) of quinoline-based Schiff bases as an inhibitoragainst α-glucosidase enzyme under positive control acarbose (IC50 = 38.45 ±â€¯0.80 µM). From the activity profile it was foundthat analogs 1, 2, 3, 4, 11, 12 and 20with IC50values 12.40 ±â€¯0.40, 9.40 ±â€¯0.30, 14.10 ±â€¯0.40, 6.20 ±â€¯0.30, 14.40 ±â€¯0.40, 7.40 ±â€¯0.20 and 13.20 ±â€¯0.40 µMrespectively showed most potent inhibition among the series even than standard drug acarbose (IC50 = 38.45 ±â€¯0.80 µM). Here in the present study analog 4 (IC50 = 6.20 ±â€¯0.30 µM) was found with many folds better α-glucosidase inhibitory activity than the reference drug. Eight analogs like 5, 7, 8, 16, 17, 22, 24 and 25 among the whole series displayed less than 50% inhibition. The substituents effects on phenyl ring thereby superficially established through SAR study. Binding interactions of analogs and the active site of ligands proteins were confirmed through molecular docking study. Spectroscopic techniques like 1H NMR, 13C NMR and ESIMS were used for characterization.

Synthesis of oxadiazole-coupled-thiadiazole derivatives as a potent ß-glucuronidase inhibitors and their molecular docking study.

A new series of oxadiazole with thiadiazole moiety (6-27) were synthesized, characterized by different spectroscopic techniques and evaluated for ß-glucuronidase inhibitory potential. Sixteen analogs such as 6, 7, 8, 9, 10, 12, 13, 14, 17, 18, 20, 23, 24, 25, 26 and 27 showed IC50 values in the range of 0.96 ±â€¯0.01 to 46.46 ±â€¯1.10 µM, and hence were found to have excellent inhibitory potential in comparison to standard d-saccharic acid 1,4-lactone (IC50 = 48.4 ±â€¯1.25 µM). Two analogs such as 16 and 19 showed moderate inhibitory potential while analogs 11, 15, 21 and 22 were found inactive. Our study identifies new series of potent ß-glucuronidase inhibitors for further investigation. Structure activity relationships were established for all compounds which showed that the activity is varied due to different substituents on benzene ring. The interaction of the compounds with enzyme active site were confirmed with the help of docking studies, which reveals that the electron withdrawing group and hydroxy group make the molecules more favorable for enzyme inhibition.

Design, synthesis, in vitro evaluation, molecular docking and ADME properties studies of hybrid bis-coumarin with thiadiazole as a new inhibitor of Urease.

Hybrid bis-coumarin derivatives 1-18 were synthesized and evaluated for their in vitro urease inhibitory potential. All compounds showed outstanding urease inhibitory potential with IC50 value (The half maximal inhibitory concentration) ranging in between 0.12 SD 0.01 and 38.04 SD 0.63 µM (SD standard deviation). When compared with the standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Among these derivatives, compounds 7 (IC50 = 0.29 ±â€¯0.01), 9 (IC50 = 2.4 ±â€¯0.05), 10 (IC50 = 2.25 ±â€¯0.05) and 16 (IC50 = 0.12 ±â€¯0.01) are better inhibitors of the urease compared with thiourea (IC50 = 21.40 ±â€¯0.21 µM). To find structure-activity relationship molecular docking as well as absorption, distribution, metabolism, and excretion (ADME) studies were also performed. Various spectroscopic techniques like 1H NMR, 13C NMR, and EI-MS were used for characterization of all synthesized analogs. All compounds were tested for cytotoxicity and found non-toxic.

New triazinoindole bearing thiazole/oxazole analogues: Synthesis, α-amylase inhibitory potential and molecular docking study.

New triazinoindole bearing thiazole/oxazole analogues (1-21) were synthesized and characterized through spectroscopic techniques such as HREI-MS, 1H and 13C NMR. The configuration of compound 2i and 2k was confirmed through NOESY. All analogues were evaluated against α-amylase inhibitory potential. Among the synthesized analogues, compound 1h, 1i, 1j, 2a and 2f having IC50 values 1.80 ±â€¯0.20, 1.90 ±â€¯0.30, 1.2 ±â€¯0.30, 1.2 ±â€¯0.01 and 1.30 ±â€¯0.20 µM respectively, showed excellent α-amylase inhibitory potential when compared with acarbose as standard (IC50 = 0.91 ±â€¯0.20 µM). All other analogues showed good to moderate inhibitory potential. Structural activity relationship (SAR) has been established and binding interactions were confirmed through docking studies.

Synthesis of new arylhydrazide bearing Schiff bases/thiazolidinone: α-Amylase, urease activities and their molecular docking studies.

Alpha-amylase and urease enzyme over expression endorses various complications like rheumatoid arthritis, urinary tract infection, colon cancer, metabolic disorder, cardiovascular risk, and chronic kidney disease. To overcome these complications, we have synthesized new arylhydrazide bearing Schiff bases/thiazolidinone analogues as α-amylase and urease inhibitors. The analogues 1a-r were evaluated for α-amylase inhibitory potential. All analogues were found active and show IC50 value ranging between 0.8 ±â€¯0.05 and 12.50 ±â€¯0.5 µM as compare to standard acarbose (IC50 = 1.70 ±â€¯0.10 µM). Among the synthesized analogs, compound 1j, 1r, 1k, 1e, 1b and 1f having IC50 values 0.8 ±â€¯0.05, 0.9 ±â€¯0.05, 1.00 ±â€¯0.05, 1.10 ±â€¯0.10, 1.20 ±â€¯0.10 and 1.30 ±â€¯0.10 µM respectively showed an excellent inhibitory potential. Analogs 2a-o were evaluated against urease activity. All analogues were found active and show IC50 value ranging between 4.10 ±â€¯0.02 and 38.20 ±â€¯1.10 µM as compare to standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Among the synthesized analogs, compound 2k, 2a, 2h, 2j, 2f, 2e, 2g, 2b and 2l having IC50 values 4.10 ±â€¯0.02, 4.60 ±â€¯0.02, 4.70 ±â€¯0.03, 5.40 ±â€¯0.02, 6.70 ±â€¯0.05, 8.30 ±â€¯0.3, 11.20 ±â€¯0.04, 16.90 ±â€¯0.8 and 19.80 ±â€¯0.60 µM respectively showed an excellent inhibitory potential. All compounds were characterized through 1H, 13C NMR and HR-EIMS analysis. Structure activity relationship of the synthesized analogs were recognized and confirmed through molecular docking studies.

A natural flavonoid lawsonaringenin induces cell cycle arrest and apoptosis in HT-29 colorectal cancer cells by targeting multiple signalling pathways.

Colorectal cancer is the third most common malignancy in the world having a high mortality rate. Flavonoids possess many biological activities including anti-cancer activity. lawsonaringenin (LSG) is a flavonoid isolated from leaves of Lawsonia alba Lam. The objective of this study was to demonstrate the anti-cancer potential of LSG in colorectal cancer for the first time. The HT-29 cells were treated with LSG or 5-fluoruracil, as a positive control, to determine its effect on cell cytotoxicity by a MTT cell proliferation assay, and cell cycle progression and apoptosis using flowcytometry. We also determined the mechanisms underlying LSG-mediated growth inhibition of HT-29 cells by by investigating the expression of key oncogenes and apoptosis genes using q-RT PCR and immunocytochemical analysis. The cell cytotoxicity data showed that the IC50 value of LSG was significantly less than the IC50 value of 5-FU (50 µM). The anti-proliferative effect of LSG was mediated by arresting cells in the S phase of the cell cycle which then led to the induction of apoptosis the q-RT PCR and immunocytochemical analysis showed that LSG reduced the expression of ß-catenin (non-phosphorylated) and its downstream signalling target c-Myc, whereas it increased the phosphorylation of ß-catenin. Furthermore, LSG also downregulated the expression of oncogene K-Ras and anti-apoptotic proteins, Bcl-2, and Bcl-xL. In conclusion, our data demonstrates that LSG exerted its anti-tumor activity by arresting the cell cycle in S phase, and by downregulating the expression of oncogenes including ß-catenin, c-Myc, K-Ras and anti-apoptosis proteins Bcl-2 and Bcl-xL. This study suggests a potential use of natural flavonoid, lawsonaringenin, to attenuate colorectal cancer growth; however, further pre-clinical/clinical studies are required to establish its role as a therapeutic agent.

Coherent intermolecular proton transfer in the acid-base reaction of excited state pyranine.

Detailed molecular dynamics simulations of an acid-base reaction have been the subject of extensive investigations. Here we report the excited state proton transfer dynamics of pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) in acetate buffer by time-resolved fluorescence (TF) and quantum mechanical/effective fragment potential molecular dynamics (QM/EFP-MD) simulations. High time resolution in TF and TF spectra measurements allows the acquisition of accurate reaction kinetics. Upon the photoexcitation of HPTS, the proton (deuterium) is transferred coherently to acetate in 60 fs (80 fs) for a contact pair of HPTS (DPTS) and acetate by a hydrogen bond, which comprises approximately 28% of the population. ESPT proceeds slowly on a picosecond time scale for the remaining HPTS as reported previously. Coherent wave packet motions of the reactant (acid) and the product (conjugate base) enable the acquisition of the vibrational spectra of excited states via TF (VETF). A comparison of the VETFs of the reactant and the product and the calculation of the Huang-Rhys factors (vibrational reorganization energies) identify the vibrational modes that actively participate in the coherent proton transfer. In particular, the 246 cm-1 vibrational mode, which consists of in-plane skeletal stretching motion, promotes the ESPT by transferring the donor oxygen towards the acceptor oxygen in acetate. QM/EFP MD simulations corroborate the experiment and provide molecular details of the ESPT.

Molecular hybridization conceded exceptionally potent quinolinyl-oxadiazole hybrids through phenyl linked thiosemicarbazide antileishmanial scaffolds: In silico validation and SAR studies.

The high potential of quinoline containing natural products and their derivatives in medicinal chemistry led us to discover a novel series of compounds 6-23 based on the concept of molecular hybridization. Most of the synthesized analogues exhibited potent leishmanicidal potential. The most potent compound (23, IC50=0.10±0.001µM) among the series was found ∼70 times more lethal than the standard drug. The current series 6-23 conceded in the development of fourteen (14) extraordinarily active compounds against leishmaniasis. In silico analysis were also performed to probe the mode of action while all the compounds structure were established by NMR and Mass spectral analysis.

Antidepressant-like deliverables from the sea: evidence on the efficacy of three different brown seaweeds via involvement of monoaminergic system.

Brown seaweeds exhibit several health benefits in treating and managing wide array of ailments. In this study, the antidepressant-like effect of methaolic extracts from Sargassum swartzii (SS), Stoechospermum marginatum (SM), and Nizamuddinia zanardinii (NZ) was examined in forced swimming test (FST), in rats. Oral administration of SS, SM, and NZ extract (30-60 mg/kg) exhibited antidepressant-like activity in FST by reducing immobility time as compared to control group, without inducing significant change in ambulatory behavior in open field test. In order to evaluate the involvement of monoaminergic system, rats were pretreated with the inhibitor of brain serotonin stores p-chlorophenylalanin (PCPA), dopamine (SCH23390 and sulpiride), and adrenoceptor (prazosin and propranolol) antagonists. Rats receiving treatment for 28 days were decapitated and brains were analyzed for monoamine levels. It may be concluded that the extracts of SS, SM, and NZ produces antidepressant-like activity via modulation of brain monoaminergic system in a rat model.

Impact of mobile phone-based technology to improve health, population and nutrition services in Rural Bangladesh: a study protocol.

BACKGROUND: Mobile phone-based technology has been used in improving the delivery of healthcare services in many countries. However, data on the effects of this technology on improving primary healthcare services in resource-poor settings are limited. The aim of this study is to develop and test a mobile phone-based system to improve health, population and nutrition services in rural Bangladesh and evaluate its impact on service delivery. METHODS: The study will use a quasi-experimental pre-post design, with intervention and comparison areas. Outcome indicators will include: antenatal care (ANC), delivery care, postnatal care (PNC), neonatal care, expanded programme on immunization (EPI) coverage, and contraceptive prevalence rate (CPR). The study will be conducted over a period of 30 months, using the existing health systems of Bangladesh. The intervention will be implemented through the existing service-delivery personnel at various primary-care levels, such as community clinic, union health and family welfare centre, and upazila health complex. These healthcare providers will be given mobile phones equipped with Apps for sending text and voice messages, along with the use of Internet and device for data-capturing. Training on handling of the Smartphones, data-capturing and monitoring will be given to selected service providers. They will also be trained on inputs, editing, verifying, and monitoring the outcome variables. DISCUSSION: Mobile phone-based technology has the potential to improve primary healthcare services in low-income countries, like Bangladesh. It is expected that our study will contribute to testing and developing a mobile phone-based intervention to improve the coverage and quality of services. The learning can be used in other similar settings in the low-and middle-income countries.

Longitudinal study of stress, social support, and depression in married Arab immigrant women.

Using a stress and social support framework, this study explored the trajectory of depression in 388 married Arab immigrant women. The women provided three panels of data approximately 18 months apart. Depression at Time 3 was regressed on Time 1 depression, socio-demographic variables, and rate of change over time in stress and social support. The regression model was significant and accounted for 41.16% of the variation in Time 3 depression scores. Time 1 depression, English reading ability, husband's employment status, changes over time in immigration demands, daily hassles, and social support from friends were associated with Time 3 depression.