RSC Adv.

Despite all the significant progresses made to enhance the efficacy of the existing bank of drugs used to manage and cure type II diabetes mellitus, there is still a need to search and develop novel bioactive compounds with superior efficacy and minimal adverse effects. This study describes the valorization of the natural bioactive sesquiterpene coumarin via the semi-synthesis of new analogs and the study of their α-amylase inhibition activity. The sesquiterpene coumarin named coladonin (1) was quantitatively isolated from the chloroform extract of endemic Ferula tunetana roots. Subsequently, the oxidation of 1 via the Jones oxidation reaction, used as a key reaction, afforded precursor 2. The condensation of oxidized coladonin (2) with various aryl aldehydes provided a series of new arylidene-based sesquiterpene coumarin derivatives (3a–m), which were characterized by NMR and ESI-HRMS experiments. All derivatives evaluated in vitro for their α-amylase inhibitory potential showed interesting α-amylase inhibition with IC50 values ranging from 7.24 to 28.98 μM. Notably, compounds 3k and 3m exhibited lower IC50 values (7.24 μM and 8.38 μM, respectively) compared to the standard (acarbose: IC50 = 9.83 μM). In addition, the structure–activity relationship (SAR) for all the compounds was studied. The most active compounds were found to be mixed-type inhibitors, which was revealed by kinetic studies. Furthermore, molecular in silico docking studies were established for all synthesized analogs with the binding site for the α-amylase enzyme

Electrochemical capacitive K+ EMIS chemical sensor based on the dibromoaza[7]helicene as an ionophore for potassium ions detection

Tounsi, Moncef et al.A K+-sensitive capacitive electrolyte-membrane-insulator-semiconductor (EMIS) based on a novel dibromoaza[7]helicene ionophore has been developed. An ion-sensitive membrane based on polyvinylchloride (PVC) doped with the ionophore was deposited on the Si3N4/SiO2/Si-p/Cu-Al transducer. The properties of the K+-EMIS chemical sensor were investigated by electrochemical impedance spectroscopy (EIS). All the developed devices upon being tested have shown good sensitivity and linearity responses within the range 10-6 M to 10-1 M of potassium activity, with good selectivity over a wide variety of other cations (Na+, Li+, Cu2+, Ca2+, and Mg2+). To our knowledge, this is the first time that a capacitive field-effect sensor has been fabricated using helicene as a carrier for a K+-detection, combined with the structure Si3N4/SiO2/Si-p/Cu-Al as a transducer.We acknowledge the funding through the European Communities Seventh Framework Programme entitled Sea-on-a-Chip (FP7-OCEAN-2013) (No.614168), the European Union's Horizon 2020 Research and Innovation Programme entitled HEARTEN under grant agreement No 643694, NATO (CBP.NUKR.SFP 984173), and FP7-PEOPLE-2012-IRSES under the grant agreement No. 318053 (SMARTCANCERSENS). M. T. would like to acknowledge PHC-12 Mag088 project, and the Ministry of Higher Education and Scientific Research of Tunisia (LR11ES55).Peer reviewe

Consideration of uncertainties in the preliminary design case of an electromagnetic spindle

Modeling and evaluation of uncertainties constitute indeed one of the key points when making any decision. For this, designers have to compare the measured or calculated value with a range of permissible values in order to obtain a guaranteed design process. Thus, in this work, simulation of the dynamic behavior of an electromagnetic spindle was done based on the interval computation technique. Indeed, the use of this technique makes it possible to obtain a set of values for different design parameters of the spindle and, consequently, to avoid making several simulations which could make the system useless, expensive or ineffective. The proposed model is based on the combination of Matlab with ModelCenter. Matlab was used to model and simulate the system and ModelCenter to perform parametric studies to verify the influences of uncertainty on the dynamic behavior of the electromagnetic spindle and to determine the optimal design parameters

A novel EIS field effect structures coated with TESUD-PPy-PVC-dibromoaza[7]helicene matrix for potassium ions detection

International audienceIn this work, we describe the development of new Aza[7]helicene-containing PVC-based membranes for the K+ ions quantification. Here, silicon nitride-based structures (Si-p/SiO2/Si3N4) were developed and the surface was activated, functionalized with an aldehyde–silane (11-(Triethoxysilyl)undecanal (TESUD)), functionalized with polypyrrole (PPy), and coated with the polyvinylchloride (PVC)-membrane containing the Aza[7]helicene as ionophore. All stages of functionalization process have been thoroughly studied by contact angle measurements (CAMs) and atomic force microscopy (AFM). The developed ion-selective electrode (ISE) was then applied using electrochemical impedance spectroscopy (EIS) for the detection of potassium ions. A linear range was observed between 1.0 × 10− 8 M to 1.0 × 10− 3 M and a detection limit of 1.0 × 10− 8 M was observed. The EIS results have showed a good sensitivity to potassium ion using this novel technique. The target helicene exhibited good solubility and excellent thermal stability with a high decomposition temperature (Td > 300 °C) and it indicates that helicene may be a promising material as ionophore for ion-selective electrodes (ISEs) elaboration

The root essential oil from the Tunisian endemic plant Ferula tunetana: Chemical composition, biological evaluation, molecular docking analysis and drug-likeness prediction

Oxidative stress is closely related to cancer aspects, such as the induction of gene mutations resulting from cellular injury and the effects on transcription and signal transduction factors. In addition, antibiotic resistance is also linked with oxidative stress, which could contribute to the selection of resistant bacterial strains. With this in mind, and considering that essential oils are well known to display antioxidant, antimicrobial, and cytotoxic activities, this study was destined to investigate the chemical composition and to screen these properties for the root essential oil (REO) of the Tunisian endemic species Ferula tunetana Pomel ex Batt. The REO GC/MS analysis led to the identification of nine compounds, representing 94.5% of the total oil composition. The phytochemical profile of this essential oil (EO) was characterized by the dominance of sesquiterpenes, comprising 11.7% of sesquiterpene hydrocarbons and 82.8% of oxygenated sesquiterpenes. The three major constituents of the EO were caryophyllene oxide (33.9%), α-cyperone (13.9%), and 14-hydroxy-9-epi-(E)-caryophyllene (12.3%). REO showed a good antioxidant potential against DPPH (IC50 = 30.13 ± 0.28 μg/mL), O2•- (IC50 = 42.87 ± 0.81 μg/mL) and H2O2 (IC50 = 48.03 ± 1.21 μg/mL). Additionally, the antimicrobial activity results showed that REO had a strong antibacterial potential against all target microbial strains, including five Gram-negative, six Gram-positive bacteria, and two Candida species (MICs = 0.039–0.625 mg/mL). Furthermore, the extracted EO was found to have good cytotoxic properties against five human cell lines viz. HT-29, HCT-116, HeLa, A549 and U937, with IC50 values ranging from 3.37 ± 0.02 to 46.66 ± 1.22 μg/mL. The main REO constituents were docked to the human DNA topoisomerase IIα enzyme and the in vitro cellular toxicities were rationalized. The drug-likeness of the main compounds identified in the studied EO was predicted. Overall, the results of the current study prove that the EO of F. tunetana roots has a noteworthy antioxidant potential and represents an interesting candidate to treat infectious diseases and cancer

Electrochemical Capacitive K + EMIS Chemical Sensor Based on the Dibromoaza[7]helicene as an Ionophore for Potassium Ions Detection

International audienceA K+-sensitive capacitive electrolyte-membrane-insulator-semiconductor (EMIS) based on a novel dibromoaza[7]helicene ionophore has been developed. An ion-sensitive membrane based on polyvinylchloride (PVC) doped with the ionophore was deposited on the Si3N4/SiO2/Si-p/Cu-Al transducer. The properties of the K+-EMIS chemical sensor were investigated by electrochemical impedance spectroscopy (EIS). All the developed devices upon being tested have shown good sensitivity and linearity responses within the range 10(-6) M to 10(-1) M of potassium activity, with good selectivity over a wide variety of other cations (Na+, Li+, Cu2+, Ca2+, and Mg2+). To our knowledge, this is the first time that a capacitive field-effect sensor has been fabricated using helicene as a carrier for K+-detection, combined with the structure: Si3N4/SiO2/Si-p/Cu-Al as a transducer