Mechanisms of antiplatelet activity of PC-09, a newly synthesized pyridazinone derivative

Stilbene-pyridazinone hybrids: design, synthesis and in vitro antiplatelet activity screening

A series of stilbene analogues, in which a phenyl ring was replaced by the pyridazin-3(2H)-one nucleus, was designed and synthesized to be explored as platelet aggregation inhibitors. The proposed stilbene-pyridazinone hybrids were successfully obtained from simple starting materials and by Wittig's reaction. Most of the target compounds displayed improved in vitro activity in comparison with the standard drug, resveratrol, highlighting as the most potent the analogues 10d and 10e, with inhibition percentages of 94.15 % at 100 µM and 100 % at 50 µM, respectively. The pharmacokinetic and toxicity (ADME/T) properties of the novel hybrids were also estimated with the SwissADME and ProTox-II web servers.

Discovery of Novel Hybrids of Edaravone and 6-Phenyl-4,5-dihydropyridazin-3(2H)-one with Antiplatelet Aggregation and Neuroprotection for Ischemic Stroke Treatment

Drugs with anti-platelet aggregation and neuroprotection are of great significance for the treatment of ischemic stroke. A series of edaravone and 6-phenyl-4,5-dihydropyridazin-3(2H)-one hybrids were designed and synthesized. Among them, 6g showed the most effective cytoprotective effect against oxygen-glucose deprivation/reoxygenation-induced damage in BV2 cells and an excellent inhibitory effect on platelet aggregation induced by adenosine diphosphate and arachidonic acid. Additionally, 6g could prevent thrombosis caused by ferric chloride in rats and pose a lower risk of causing bleeding compared with aspirin. It provides better protection against ischemia/reperfusion injury in rats compared with edaravone and alleviates the oxidative stress related to cerebral ischemia/reperfusion by increasing the GSH and SOD levels and decreasing the MDA concentration. Finally, molecular docking results showed that 6g probably acts on PDE3 A and plays an anti-platelet aggregation effect. Overall, 6g could be a potential candidate compound for the treatment of ischemic stroke.

Microwave-Assisted One Pot Three-Component Synthesis of Novel Bioactive Thiazolyl-Pyridazinediones as Potential Antimicrobial Agents against Antibiotic-Resistant Bacteria

Pyridazine and thiazole derivatives have various biological activities such as antimicrobial, analgesic, anticancer, anticonvulsant, antitubercular and other anticipated biological properties. Chitosan can be used as heterogeneous phase transfer basic biocatalyst in heterocyclic syntheses. Novel 1-thiazolyl-pyridazinedione derivatives were prepared via multicomponent synthesis under microwave irradiation as ecofriendly energy source and using the eco-friendly naturally occurring chitosan basic catalyst with high/efficient yields and short reaction time. All the prepared compounds were fully characterized by spectroscopic methods, and their in vitro biological activities were investigated. The obtained results were compared with those of standard antibacterial/antifungal agents. DFT calculations and molecular docking studies were used to investigate the electronic properties and molecular interactions with specific microbial receptors.

The construction of fluorophoric thiazolo-[2,3-b]quinazolinone derivatives: a multicomponent domino synthetic approach

Acid-mediated one-pot domino reactions of substituted 2-amino thiazoles, substituted benzaldehydes and cyclic diketones have been developed for the synthesis of novel and architecturally unique thiazolo[2,3-b]quinazolinone derivatives under microwave irradiation. In this protocol, a series of thiazolo[2,3-b]quinazolinone derivatives have been synthesized and the excellent fluorescence behaviors of some of the molecules have been reported based on the incorporation of different electron-donating and electron-withdrawing substituents on the aryl moieties of the target molecules.

A library of unique fluorophoric thiazolo[2,3-b]quinazolinones were synthesized under acid catalyzed one pot microwave irradiation technique.

Mechanisms of the antiplatelet and analgesic effects of dextromethorphan and its metabolites

Objective:

In the present study, we investigated the effects of dextromethorphan (DM) and its metabolites, including dextrorphan (LK2), 3-methoxymorphinan (LK3), and 3-hydroxymorphinan (LK4), on platelet aggregation in vitro and the inflammatory pain caused by carrageenan in rats, and their underlying mechanisms.

Materials and Methods:

Rabbit platelets were pretreated with DM or its metabolites to assess their effects on platelet aggregation and related target mediators. In addition, the analgesic activity and the underlying mechanisms of DM and LK3 were investigated in a carrageenan-evoked thermal hyperalgesia rat model.

Results:

The inhibitory potency of DM and its metabolites on platelet aggregation induced by arachidonic acid or collagen was LK3> DM > LK4>> LK2 as demonstrated by the half-maximal inhibitory concentration values. Moreover, the mechanisms of the antiplatelet effect of DM and LK3 may involve the inhibition of intracellular calcium mobilization, expression of platelet surface glycoprotein IIb/IIIa, the formation of thromboxane B₂, and elevation of platelet membrane fluidity. DM and LK3 also exhibited analgesic effects on carrageenan-evoked thermal hyperalgesia by suppressing the production of pro-inflammatory cytokines, nitric oxide, prostaglandin E₂, and neutrophil infiltration in inflammatory sites.

Conclusion:

DM and its metabolites, especially LK3, exhibit both antiplatelet and analgesic effects, and may, therefore, potentially ameliorate platelet hyperactivity and inflammatory-related diseases.

Novel compounds of hybrid structure pyridazinone–coumarin as potent inhibitors of platelet aggregation

Aim: The current limitations of antiplatelet therapy promote the search for new antithrombotic agents. Here we describe novel platelet aggregation inhibitors that combine pyridazinone and coumarin scaffolds in their structure. Results: The target compounds were synthesized in good yield from maleic anhydride, following a multistep strategy. The in vitro studies demonstrated significant antiplatelet activity in many of these compounds, with IC50 values in the low micromolar range, revealing that the activity was affected by the substitution pattern of the two selected cores. Additional studies point out their effect as inhibitors of glycoprotein (Gp) IIb/IIIa activation. Conclusion: This novel hybrid structure can be considered a good prototype for the development of potent platelet aggregation inhibitors.

The Study of Pyridazine Compounds on Prostanoids: Inhibitors of COX, cAMP Phosphodiesterase, and TXA2Synthase

The pyridazine moiety is an important structural feature of various pharmacological active compounds. Synthetic pyridazine compounds have been reported as effective antiprostaglandins (PGs), 5-lipoxygenase (5-LOX), and antiplatelet agents, that is, inhibitors of prostaglandin or cyclooxygenase (COX-I & COX-II) enzyme, platelet cAMP phosphodiesterase, and thromboxane A2 (TXA2) synthase. These compounds are selective and nonselective COX inhibitors and showed analgesic, anti-inflammatory, and antipyretic activity. Pyridazine compounds with antiplatelet agents inhibited TXA2enzyme. Pyridazines also exhibited antirheumatoid activity. These pyridazine compounds hold considerable interest relative to the preparation of organic intermediates and other anticipated biologically active compounds.

1H and 13C spectral assignment of substituted 5H-[1,3]thiazolo[2,3-b]quinazolin-5-one and 12H-[1,3]benzothiazolo[2,3-b] quinazolin-12-one

(1)H and (13)C spectroscopic data for 5H-[1,3]thiazolo[2,3-b]quinazolin-5-one and 12H-[1,3]benzothiazolo[2,3-b]quinazolin-12-one derivatives were fully assigned by combination of one- and two-dimensional experiments (DEPT, HMBC and HMQC). Both heterocyclic systems show similar spectroscopic properties with some remarkable differences.