Identification of Novel Rho-Kinase-II Inhibitors with Vasodilatory Activity

Clerodendrum Glandulosum Lindl.: A Review of Ethnopharmacology, Pharmacological Potentials, and their Mechanism of Action

Clerodendrum glandulosum Lindl. is popularly known for its traditional herbal remedies and therapeutic properties among the people of Northeast Indian communities, as well as Chinese traditional medicine. For the myriad pharmacological properties, viz., anti-hypertensive, hypolipidemic, hepatoprotective, anti-inflammatory, and neuroprotective, planting this species in kitchen gardens is a common practice to treat various ailments, especially hypertension, diabetes, and other metabolic complications. Different phytochemicals, representing the diverse classes of secondary metabolites comprising physiological and phytopharmaceutical significance, have been reported from C. glandulosum. Compounds with terpenoids, steroids, and phenolics are in demand in the pharmaceutical industry. An overview of the mechanism of action of the prominent compounds has also been collated for future research on C. glandulosum-based therapeutics. Current information focuses on this important medicinal plant's ethnomedicinal use, phytochemistry, pharmacology, associated mechanisms, and toxicology. This review will help explore this potential medicinal plant, which can pave the path for its application in the pharmaceutical industry.

QSAR Studies and Scaffold Optimization of Predicted Novel ACC 2 Inhibitors to Treat Metabolic Syndrome

BACKGROUND

Metabolic syndrome is one of the major non-communicable global health hazards of the modern world owing to its amplifying prevalence. Acetyl coenzyme-A carboxylase 2 (ACC 2) is one of the most crucial enzymes involved in the manifestation of this disease because of its regulatory role in fatty acid metabolism.

OBJECTIVE

To find novel potent ACC 2 inhibitors as therapeutic potential leads for combating metabolic syndrome.

METHODS

In the present study, a two-dimensional quantitative structure-activity relationship (2D QSAR) approach was executed on biologically relevant thiazolyl phenyl ether derivatives as ACC 2 inhibitors for structural optimization. The physiochemical descriptors were calculated and thus a correlation was derived between the observed and predicted activity by the regression equation. The significant descriptors i.e. log P (Whole Molecule) and Number of H-bond Donors (Substituent 1) obtained under study were considered for the design of new compounds and their predicted biological activity was calculated from the regression equation of the developed model. The compounds were further validated by docking studies with the prepared ACC 2 receptor.

RESULTS

The most promising predicted leads with the absence of an H-bond donor group at the substituted phenyl ether moiety yet increased overall lipophilicity exhibited excellent amino acid binding affinity with the receptor and showed predicted inhibitory activity of 0.0025 μM and 0.0027 μM. The newly designed compounds were checked for their novelty. Lipinski's rule of five was applied to check their druggability and no violation of this rule was observed.

CONCLUSION

The compounds designed in the present study have tremendous potential to yield orally active ACC 2 inhibitors to treat metabolic syndrome.

Recent advances in the development of Rho kinase inhibitors (2015-2021)

Rho-associated coiled-coil kinases (ROCKs) are key downstream effectors of small GTPases. ROCK plays a central role in diverse cellular events with accumulating evidence supporting the concept that ROCK is important in tumor development and progression. Numerous ROCK inhibitors have been investigated for their therapeutic potential in the treatment of cancers. In this article, we review recent research progress on ROCK inhibitors, especially those with potential for the treatment of cancers, reported in the literature from 2015 to 2021. Most ROCK inhibitors show potent in vitro and in vivo antitumor activities and have potential in the treatment of cancers.

Discovery of indoline-based derivatives as effective ROCK2 inhibitors for the potential new treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and devastating lung disease with a median survival of only 3-5 years. Due to the lack of effective therapy, IPF threatens human health. Recently, increasing reports have indicated that Rho-associated coiled-coil protein kinases (ROCKs) play important roles in the development of IPF and might represent a novel target for the treatment of IPF. Herein, a new series of selective ROCK2 inhibitors based on indoline were designed and synthesized. Structural modification resulted in optimized compound 9b with an IC₅₀ value of 6 nM against ROCK2 and the inhibition of collagen gel contraction. Cellular assays demonstrated that 9b could significantly suppress the expression of collagen I and α-SMA, and inhibited ROCK signaling pathway. Oral administration of compound 9b (10 mg/kg) exerted more significant anti-pulmonary fibrosis effects than nintedanib (100 mg/kg) and KD025 (100 mg/kg) in a bleomycin-induced IPF rat model, suggesting that 9b could serve as a potential lead compound for the treatment of IPF.

New insights on mode of action of vasorelaxant activity of simvastatin

Simvastatin is a semisynthetic inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and is used extensively to treat atherosclerotic cardiovascular disease. Apart from the lipid-lowering effect, simvastatin has been documented to offer impressive vasorelaxant activity. However, the mechanism associated with this vasorelaxant activity has yet not been substantially explored. Thus, the present study has aimed to elucidate the mechanism(s) associated with simvastatin-induced vasorelaxation using an established rat aortic ring model. The results from the study depicted that simvastatin caused significant relaxation in aortic rings pre-contracted with phenylephrine and potassium chloride (KCl). The vasorelaxant effect of simvastatin was attenuated by methylene blue (sGC-dependent cyclic guanosine monophosphate (cGMP) inhibitor), N^G-nitro-L-arginine methyl ester (L-NAME; NO synthase inhibitor), 4-aminopyridine (K_v blocker), glibenclamide (K_ATP blocker), and barium chloride (K_ir blocker). In addition, the vasorelaxant effect of simvastatin was slightly reduced by PD123319 (angiotensin II type 2 receptor (AT₂R) antagonist). However, indomethacin (COX inhibitor), 1H-[1,2,4]Ox adiazolol [4,3-α]quinoxalin-1-one (ODQ; selective soluble guanylate cyclase (sGC) inhibitor), losartan (angiotensin II type 1 receptor (AT₁R) antagonist), atropine (muscarinic receptor blocker), and tetraethyl ammonium (TEA; K_Ca blocker) did not affect the vasorelaxant effect of simvastatin. Furthermore, simvastatin was found to attenuate the release of calcium (Ca²⁺) from intracellular stores in the presence of ruthenium red (ryanodine receptor, RyR inhibitor) and extracellular stores via nifedipine (voltage-operated Ca²⁺ channels, VOCC blocker) and SK&F96365 (receptor-operated Ca²⁺ channel, ROCC blocker). Thus, it can be concluded that the vasorelaxant effect of simvastatin involves NO/cGMP pathways, AT₂R receptors, Ca²⁺ channels, and K⁺ channels.

Repositioning of tubocurarine as analgesic and anti-inflammatory agent: Exploring beyond myorelaxant activity

BACKGROUND AND PURPOSE

Tubocurarine (d-TC), a non-depolarizing competitive blocker of nicotinic acetylcholine receptors is extensively utilized for the relaxation of skeletal muscles. Drug repositioning is a forthright approach to reduce the cost and speed up drug development process. Herein, we have attempted to evaluate the analgesic and anti-inflammatory activity of d-TC for its possible repurposing in pain and inflammation-related issues.

EXPERIMENTAL APPROACH

We examined the soluble epoxide hydrolase inhibitory (sEHI) activity of d-TC employing in silico high throughput screening protocols, in vitro cell-free sEH inhibitory assay, and in in vivo rodent models for its repositioning in pain and inflammation-related disorders.

KEY RESULTS

In molecular docking study, d-TC displayed impressive hydrogen bonding interactions within the cavity of sEH enzyme with good docking score. d-TC also exhibited notable sEH inhibitory activity (IC₅₀ 3.72 nm) at the in vitro assay. Oral absorption capability of d-TC (0.1 and 0.2 mg/mL) was determined using an in vitro everted intestinal sac model employing rat ileum tissue that revealed significant oral absorption of d-TC. Besides, in vivo studies revealed that oral administration of d-TC (0.1 and 0.2 mg/kg) in rodents significantly attenuated hyperalgesia (cold plate test, tail immersion test and formalin test) and inflammation (estimation of rectal temperature, acetic acid induced pleurisy test and cotton pellet-induced granuloma test) induced in robust preclinical models. Conclusion and implications These findings are novel and warrant immediate efforts to reposition d-TC as a new therapeutic candidate in the management of hyperalgesia, inflammation, and associated conditions.

Repurposing of digoxin in pain and inflammation: An evidence-based study

In recent years, the drug repositioning strategy has gained considerable attention in the drug discovery process that involves establishing new therapeutic uses of already known drugs. In line with this, we have identified digoxin a cardiac glycoside, as a potent inhibitor of soluble epoxide hydrolase (sEH) enzyme employing in silico high throughput screening protocols and further confirmed using in vitro cell-free sEH inhibitory assay and in vivo preclinical studies in rodents for its repurposing in hyperalgesia, inflammation, and related disorders. Oral administration of digoxin at dose 0.2 mg/kg significantly reduced (p < .0001) the allodynia in mice induced by using hot plate (3.6 ± 1.9) and tail-flick test (7.58 ± 0.9). In addition, digoxin at a dose of 0.2 mg/kg showed marked reduction (94%, p < .0001) in acetic acid-induced abdominal contraction in rats. Further, digoxin also demonstrated antipyretic activity (37.04 ± 0.2, p < .0001) and showed notable reduction (0.60 ± 0.06) in carrageenan-induced paw edema in rats. Also, the histopathological evaluation revealed that digoxin treatment attenuated the edema, neutrophil infiltration, and alveolar septal thickening in lung tissue. These findings are novel and highlight the newer insights towards repurposing digoxin as a new lead in the treatment of hyperalgesia, inflammation, and related disorders.

Simvastatin ameliorates oxidative stress levels in HepG2 cells and hyperlipidemic rats

Simvastatin is an established anti-hyperlipidemic drug and few studies have indicated its role in the mitigation of oxidative stress. However, a systematic study considering molecular binding/interaction of simvastatin with anti-oxidant enzymes followed by confirmational in vitro and in vivo studies have never been done. We investigated the molecular binding of simvastatin with multiple anti-oxidant enzymes and assessed their levels after the treatment of simvastatin in vitro and in vivo. This study is the first to show the molecular binding of simvastatin to catalase through molecular docking analysis. Moreover, the anti-oxidative properties of simvastatin have not been studied in Lipopolysaccharide (LPS) induced oxidative stress in HepG2 cells. We found that simvastatin effectively attenuated oxidative stress in LPS induced HepG2 cells and high-fat diet (HFD) fed hyperlipidemic rats by increasing the levels of antioxidant enzymes. The activity of catalase and superoxide dismutase (SOD) both increased significantly in oxidatively stressed HepG2 cells after the treatment with simvastatin (10 ​μM, 24 ​h). In addition to this, he original cell morphology of oxidatively stressed cells was restored by simvastatin, and an increase in antioxidant enzymes, catalase (0.08 U/cells to 0.12 U/cells), and SOD (0.57 U/cells to 0.74 U/cells) was also noted in HepG2 cells. Furthermore, a significant increase in the antioxidant enzymes such as Catalase, SOD, and reduced glutathione (GSH) was noted after simvastatin treatment in the HFD model. Moreover, we also observed degradation of by-products of lipid peroxidation thiobarbituric acid reactive substances (TBARs), nitric oxide (NO), and protein carbonyl levels. This indicates that simvastatin enhances anti-oxidant enzyme activities and can be repurposed for the treatment of oxidative stress in liver diseases in humans after extensive clinical trials.

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In silico, molecular docking analysis shows that simvastatin binds to the active site of the catalase enzyme.

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Simvastatin attenuates LPS induced oxidative stress in HepG2 cells by increasing the amount of antioxidant enzymes catalase and SOD.

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Simvastatin significantly reduces triglycerides, cholesterol, LDL, VLDL, and increases HDL level in HFD induced oxidative stress in Wistar rats.

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Simvastatin can be repurposed for the treatment of oxidative stress in liver diseases.