Unraveling the Mechanism of Platelet Aggregation Suppression by Monoterpenoids

Platelet aggregation causes various diseases and therefore challenges the development of novel antiaggregatory drugs. In this study, we report the possible mechanism of platelet aggregation suppression by newly synthesized myrtenol-derived monoterpenoids carrying different heteroatoms (sulphur, oxygen, or nitrogen). Despite all tested compounds suppressed the platelet aggregation in vitro, the most significant effect was observed for the S-containing compounds. The molecular docking confirmed the putative interaction of all tested compounds with the platelet’s P2Y12 receptor suggesting that the anti-aggregation properties of monoterpenoids are implemented by blocking the P2Y12 function. The calculated binding force depended on heteroatom in monoterpenoids and significantly decreased with the exchanging of the sulphur atom with oxygen or nitrogen. On the other hand, in NMR studies on dodecyl phosphocholine (DPC) as a membrane model, only S-containing compound was found to be bound with DPC micelles surface. Meanwhile, no stable complexes between DPC micelles with either O- or N-containing compounds were observed. The binding of S-containing compound with cellular membrane reinforces the mechanical properties of the latter, thereby preventing its destabilization and subsequent clot formation on the phospholipid surface. Taken together, our data demonstrate that S-containing myrtenol-derived monoterpenoid suppresses the platelet aggregation in vitro via both membrane stabilization and blocking the P2Y12 receptor and, thus, appears as a promising agent for hemostasis control.

Synthesis Luminescent Plasmonic Silver Nanoparticles and The Chemical Affinity towards sulphur atom in Sulphide and Thiourea molecules: Ab-Initio DFT Study

Three different luminescent silver nanoparticles(AgNPs) were synthesized by simple reduction method with the different mole ratios of L-ascorbic/citrate solution and stabilized with CTAB. The prepared three AgNPs were characterized by UV, fluorescence, FTIR, dynamic light scattering measurements and Scanning Electron Microscopy. The plasmon bands of AgNPs- reddish-brown (RB), green (G) and reddish-green (RG) were centered at 565, 587 and 592 nm, respectively. The highly luminescence emission was observed for AgNPs(G). The size diameters of the prepared AgNPs-G, RG and (RB) were measured by dynamic light scattering (DLS) method at 24.3 nm, 66.28 nm and 103.46 nm, respectively. The electrochemical properties of AgNPs-RG was recorded the oxidative part of AgNPs into Ag+ at +0.23 V and the reduction part of Ag+ into Ag0 was recorded at -0.49 V vs. Ag/AgCl). Cetyl trimethylammonium bromide (CTAB) was stabilized AgNPs(RG) which recorded in infrared and scanning electron microscope measurements. The concentration of thiourea, sodium sulphide was detected by the electrochemical sensitivity of AgNPs(RG)-CTAB. A calibration curve between electrochemical sensitivity of AgNPs-CTAB vs concentration of sulphur molecule. The limit of detection (LOD) was founded 2.10 and 1.90 µmole L-1 of sodium sulphide and thiourea, respectively (R2=0.94, n=3). The computational calculations are used to illustrated the chemical affinity of sulphur atom in sodium sulphide or thiourea towards AgNPs(RG).

Synthesis of a New Type of Trans-Decalin Vitamin D Analogue through a Dyotropic Ring Expansion

A new vitamin D analogue with a trans-fused decalin as the CD-ring system and containing a sulphur atom in the side chain has been synthesized in our research group. The obtention of this analogue is based on a recently discovered transformation of hydrindane cores into decalins through a dyotropic ring expansion in very mild conditions.

Quinolinophenothiazine as Electron Rich Fragment for RGB Single-Layer Phosphorescent Organic Light-Emitting Diodes

The quinolinophenothiazine (QPTZ) fragment is a phenylacridine bridged by a sulphur atom. Despite appealing properties induced by this bridging (e.g. strong electron rich character), this fragment remains almost unexplored to...

Monoorganosilicon(IV) Complexes of 2-Aminocyclopentene-1-carbodithioic Acid and its N-/S-Alkyl Derivatives: Synthesis and Characterization

2-Aminocyclopentene-1-carbodithioic acid (ACDA) and its N-/S-alkyl derivatives of methylsilicon(IV) chloride have been synthesized by the reactions of MeSiCl3 with sodium salt of ACDA and its N-/S-alkyl derivatives in 1:1 and 1:2 molar ratios. All these complexes have been characterized by elemental analysis, molecular weight measurements and spectroscopic (IR, 1H and 13C NMR) studies. The central silicon atom is coordinated to two sulphur atoms or one sulphur atom and one nitrogen atom of the ligand moiety in all of these derivatives, resulting in five and six coordination.

Theoretical Insights into the Aerobic Hydrogenase Activity of Molybdenum–Copper CO Dehydrogenase

The Mo/Cu-dependent CO dehydrogenase from O. carboxydovorans is an enzyme that is able to catalyse CO oxidation to CO 2 ; moreover, it also expresses hydrogenase activity, as it is able to oxidize H 2 . Here, we have studied the dihydrogen oxidation catalysis by this enzyme using QM/MM calculations. Our results indicate that the equatorial oxo ligand of Mo is the best suited base for catalysis. Moreover, extraction of the first proton from H 2 by means of this basic centre leads to the formation of a Mo–OH–Cu I H hydride that allows for the stabilization of the copper hydride, otherwise known to be very unstable. In light of our results, two mechanisms for the hydrogenase activity of the enzyme are proposed. The first reactive channel depends on protonation of the sulphur atom of a Cu-bound cysteine residues, which appears to favour the binding and activation of the substrate. The second reactive channel involves a frustrated Lewis pair, formed by the equatorial oxo group bound to Mo and by the copper centre. In this case, no binding of the hydrogen molecule to the Cu center is observed but once H 2 enters into the active site, it can be split following a low-energy path.

The role of S-bond in tenoxicam keto–enolic tautomerization

A non-covalent interaction between the sulphur atom of thiophenyl moiety and oxygen of the carbonyl group (S-bond) plays a crucial role in keto–enol tautomerization of tenoxicam leading to the crystallization of latter only in zwitterionic (ZWC) and not in β-keto–enolic (BKE) form.

Regulating glutathione-responsiveness of naphthalimide-based fluorescent probes by an oxidation strategy

Naphthalimide-based probes with the different oxidation state of sulphur atom can be utilized to regulate the responsiveness of probes towards glutathione.