Coumarin sulfonates: As potential leads for ROS inhibition

Cardiopreventive capacity of a novel (E)-N'-(1-(7-methoxy-2-oxo-2H-chromen-3-yl) ethylidene)-4-methylbenzenesulfonohydrazide against isoproterenol-induced myocardial infarction by moderating biochemical, oxidative stress, and histological parameters

This study is carried out to assess the cardiopreventive effect of (E)-N'-(1-(7-methoxy-2-oxo-2H-chromen-3-yl) ethylidene)-4-methylbenzenesulfonohydrazide or SHC, a novel synthesized coumarin, against myocardial infarction induced by isoproterenol (ISO). The SHC compound was identified and characterized by spectral methods (infrared, ¹ H NMR [nuclear magnetic resonance], ¹³ C NMR, Nuclear Overhauser Effect Spectroscopy, and high-resolution mass spectroscopy). Male Wistar rats were divided into four groups: Control, ISO (rats were injected subcutaneously by 85 mg/kg body weight [BW] of isoproterenol at Days 6 and 7 of the experience), ISO + SHC (150 µg/kg BW, orally for 7 days) and ISO + acenocoumarol (150 µg/kg BW, orally for 7 days). Results showed that ISO induced a remarkable alteration of electrocardiogram (ECG) pattern and increases of plasma cardiac troponin T, creatine kinase-MB, total cholesterol, triglycerides, low-density lipoprotein-cholesterol, lactate dehydrogenase, aspartate transaminase, and malondialdehyde. In addition, ISO reduced the high-density lipoprotein-cholesterol content and the activities of superoxide dismutase and glutathione peroxidase, with the induction of myocardial necrosis. However, SHC administration revealed a significant decrease in cardiac dysfunction markers, restored normal ECG pattern, as well as improving lipids parameters. Moreover, SHC treatment remarkably alleviated the cardiac oxidative stress and the myocardial remodeling process. Overall, the SHC offers good protection from acute myocardial infarction through the antioxidant capacity.

Dehydrodieugenol B and hexane extract from Endlicheria paniculata regulate inflammation, angiogenesis, and collagen deposition induced by a murine sponge model

The present study reports the evaluation of hexane extract from Endlicheria paniculata and its main metabolite dehydrodieugenol B in the inflammatory response induced by a murine implant sponge model. As a result, a reduction in the inflammatory markers (myeloperoxidase and N-acetyl-β-D-glucosaminidase) and number of mast cells were observed in comparison to the control group. All doses were also able to reduce angiogenic parameters evaluated in fibrovascular tissue. In implants treated with dehydrodieugenol B a reduction in total collagen deposition and types I and III collagen fibers were observed, while an increased in total collagen deposition and types I and III collagen fibers were observed in the treatment with hexane extract. Docking studies into cyclooxygenase-2 active site revealed that the dehydrodieugenol B had binding modes and energies comparable with celecoxib, diclofenac and ibuprofen. Therefore, dehydrodieugenol B was able to alter key components of chronic inflammation, resulting in a reduced inflammatory response and also presenting antifibrogenic and antiangiogenic effects. However, treatment with hexane extract resulted in a reduced inflammatory response with antiangiogenic effects, but caused fibrogenic effects.

Overview on developed synthesis procedures of coumarin heterocycles

Considering highly valuable biological and pharmaceutical properties of coumarins, the synthesis of these heterocycles has been considered for many organic and pharmaceutical chemists. This review includes the recent research in synthesis methods of coumarin systems, investigating their biological properties and describing the literature reports for the period of 2016 to the middle of 2020. In this review, we have classified the contents based on co-groups of coumarin ring. These reported methods are carried out in the classical and non-classical conditions particularly under green condition such as using green solvent, catalyst and other procedures.

Semi-synthesis and biological evaluation of flavone hybrids as multifunctional agents for the potential treatment of Alzheimer's disease

7-O-galloyltricetiflavan (GTF), a natural flavonoid, is known to exert anti-oxidation and neuroprotective activity, which are related to the prevention of Alzheimer's disease (AD). In this study, three series of GTF hybrids have been designed, synthesized and evaluated as multifunctional agents for treatment AD. The biological assays indicated that most of them showed strong inhibitory effect on self-induced β-amyloid (Aβ) aggregation, and a significant ability to inhibit ChEs. Among them, compound A15 exhibited best inhibition of Aβ aggregation (78.81% at 20 μM), potent AChE inhibitory potencies (IC₅₀, 0.56 μM), and compound C4 presented the highest ability to inhibit BuChE (IC₅₀, 5.77 μM). Furthermore, kinetic, molecular modeling and molecular dynamics studies revealed that A15 and C4 could interact with the catalytic active site of AChE and BuChE, respectively. In addition, compounds A15 and C4 could cross the blood-brain barrier in vitro. More importantly, A15 and C4 also showed excellent neuroprotective activities against H₂O₂-induced human neuroblastoma SH-SY5Y cells damage and nearly no toxicity on SH-SY5Y cells. All of these outstanding in vitro results indicated A15 and C4 as the leading structure worthy of further investigation.

Diversified Thiazole Substituted Coumarins and Chromones as Non- Cytotoxic ROS and NO Inhibitors

Background:

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin, indomethacin, flufenamic acid and phenylbutazone are used to treat most of the inflammatory disorders. These NSAIDs are also associated with serious side effects including gastric ulceration, nephrotoxicity, and bleeding, mainly due to acidic nature. Hence, there is a need to identify highly potent and safer treatment for inflammatory disorders.

Methods:

Herein, synthetic hydrazinyl thiazole substituted coumarins and chromones 1-48 were evaluated for ROS inhibitory activity. ROS were generated from zymosan activated whole blood phagocytes.

Results:

Among all tested compounds, compounds 1 (IC50 = 38.3 ± 7.1 μM), 2 (IC50 = 5.7 ± 0.2 μM), 5 (IC50 = 28.3 ± 3.5 μM), 23 (IC50 = 12.5 ± 3.1 μM), 27 (IC50 = 32.8 ± 1.1 μM), 39 (IC50 = 20.2 ± 1.6 μM), and 42 (IC50 = 43.2 ± 3.8 μM) showed potent ROS inhibition as compared to standard ibuprofen (IC50 = 54.3 ± 1.9 μM). Whereas, compounds 3 (IC50 = 134.7 ± 1.0 μM), 16 (IC50 = 75.4 ± 7.2 μM), 24 (IC50 = 102.4 ± 1.0 μM), and 31 (IC50 = 86.6 ± 1.5 μM) were found to be moderately active. Compounds 1, 2, 5, 23, 27, 39, and 42, having potent ROS inhibitory activity were also screened for their nitric oxide (NO) inhibition. Cytotoxicity was also checked for all active compounds on NIH-3T3 cell line. Cyclohexamide (IC50 = 0.13 ± 0.02 μM) was used as standard.

Conclusion:

Identified active compounds from these libraries may serve as lead candidates for future research in order to obtain a more potent, and safer anti-inflammatory agent.

Hypervalent Iodine(III)-Mediated Tosyloxylation of 4-Hydroxycoumarins

An efficient approach was developed for synthesis of 3-tosyloxy-4-hydroxycoumarins under mild conditions by using Koser's reagents. The reaction tolerated various functional groups, and the products served as useful aromatic building blocks. Additionally, a plausible mechanism via iodonium ylide was proposed, and the oral anticoagulant Warfarin was synthesized in good yield.

New Hybrid Scaffolds based on Hydrazinyl Thiazole Substituted Coumarin; As Novel Leads of Dual Potential; In Vitro α-Amylase Inhibitory and Antioxidant (DPPH and ABTS Radical Scavenging) Activities

Background:

Despite many side effects associated, there are many drugs which are being clinically used for the treatment of type-II diabetes mellitus (DM). In this scenario, there is still need to develop new therapeutic agents with more efficacy and less side effects. By keeping in mind the diverse spectrum of biological potential associated with coumarin and thiazole, a hybrid class based on these two heterocycles was synthesized.

Method:

Hydrazinyl thiazole substituted coumarins 4-20 were synthesized via two step reaction. First step was the acid catalyzed reaction of 3-formyl/acetyl coumarin derivatives with thiosemicarbazide to form thiosemicarbazone intermediates 1-3, followed by the reaction with different phenacyl bromides to afford products 4-20. All the synthetic analogs 4-20 were characterized by different spectroscopic techniques such as EI-MS, HREI-MS, 1H-NMR and 13C-NMR. Stereochemical assignment of the iminic double bond was carried out by the NOESY experiments. Elemental analysis was found in agreement with the calculated values.

Results:

Compounds 4-20 were screened for α-amylase inhibitory activity and showed good activity in the range of IC50 = 1.829 ± 0.102-3.37 ± 0.17 µM as compared to standard acarbose (IC50 = 1.819 ± 0.19 µM). Compounds were also investigated for their DPPH and ABTS radical scavenging activities and displayed good radical scavenging potential. In addition to that molecular modelling study was conducted on all compounds to investigate the interaction details of compounds 4-20 (ligands) with active site (receptor) of enzyme.

Conclusion:

The newly identified hybrid class may serve as potential lead candidates for the management of diabetes mellitus.

Novel cinnamamide-dibenzylamine hybrids: Potent neurogenic agents with antioxidant, cholinergic, and neuroprotective properties as innovative drugs for Alzheimer's disease

By using fragments endowed with interesting and complementary properties for the treatment of Alzheimer's disease (AD), a novel series of cinnamamide-dibenzylamine hybrids have been designed, synthesized, and evaluated biologically. In vitro assay indicated that most of the target compounds exhibited a significant ability to inhibit ChEs, strong potency inhibitory of self-induced β-amyloid (Aβ) aggregation and to act as potential antioxidants and biometal chelators. A Lineweaver-Burk plot and molecular modeling study showed that compound 7f targeted both the CAS and PAS of AChE. In addition, compound 7f could chelate metal ions, reduce PC12 cells death induced by oxidative stress and penetrate the blood-brain barrier (BBB). Overall, all of these outstanding in vitro results in combination with promising in vivo outcomes highlighted derivative 7f as the lead structure worthy of further investigation.