Anti-Inflammatory Effects of Auranamide and Patriscabratine-Mechanisms and In Silico Studies.

Auranamide and patriscabratine are amides from Melastoma malabathricum (L.) Smith. Their anti-inflammatory activity and nuclear factor erythroid 2-related factor 2 (NRF2) activation ability were evaluated using Escherichia coli lipopolysaccharide (LPSEc)-stimulated murine macrophages (RAW264.7) and murine hepatoma (Hepa-1c1c7) cells, respectively. The cytotoxicity of the compounds was assessed using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. The anti-inflammatory activity was determined by measuring the nitric oxide (NO) production and pro-inflammatory cytokines (Interleukin (IL)-1ß, Interferon (IFN)-γ, tumour necrosis factor (TNF)-α, and IL-6) and mediators (NF-κB and COX-2). NRF2 activation was determined by measuring the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) quinone oxidoreductase 1 (NQO1), nuclear NRF2 and hemeoxygenase (HO)-1. In vitro metabolic stability was assessed using the mouse, rat, and human liver microsomes. The compounds were non-toxic to the cells at 10 µM. Both compounds showed dose-dependent effects in downregulating NO production and pro-inflammatory cytokines and mediators. The compounds also showed upregulation of NQO1 activity and nuclear NRF2 and HO-1 levels. The compounds were metabolically stable in mouse, rat and human liver microsomes. The possible molecular targets of NRF2 activation by these two compounds were predicted using molecular docking studies and it was found that the compounds might inhibit the Kelch domain of KEAP1 and GSK-3ß activity. The physicochemical and drug-like properties of the test compounds were predicted using Schrodinger small molecule drug discovery suite (v.2022-2).

Synthesis of New Shogaol Analogues as NRF2 Activators and Evaluation of Their Anti-Inflammatory Activity, Modes of Action and Metabolic Stability.

6-shogaol is a natural and the most potent bioactive vanilloid in dried Zingiber officinale rhizomes. Many scientific studies have reported the diverse biological activities of 6-shogaol. However, the major drawback of 6-shogaol is its instability at room temperature. We synthesised new shogaol thiophene compounds (STCs) by replacing the pentyl group in the sidechain with thiophene derivatives. The STCs were tested for their nuclear factor erythroid 2-related factor 2 (NRF2) activation ability in murine hepatoma cells (Hepa1c1c-7) by determining their NAD(P)H quinone oxidoreductase 1 (NQO1) inducing ability and expression of NRF2-associated antioxidant genes. The anti-inflammatory activity of STCs was determined in Escherichia coli lipopolysaccharide (LPSEc)-stimulated NR2-proficient and -silenced mouse microglial cells (BV-2) by measuring the inflammatory markers, cytokines, and mediators. The modes of action (interacting with the Kelch domain of KEAP1, covalent bonding with cysteines of KEAP1, and inhibition of GSK-3ß enzyme activity) of NRF2 activation by STCs were determined using commercially available kits. The in vitro metabolic stability of the STCs in liver microsomes (humans, rats, and mice) was also investigated. The molecular docking and molecular dynamics studies were conducted to identify the binding poses, stability, and molecular interactions of the STCs in the binding pockets of Kelch and BTB domains of KEAP1 and GSK-3ß enzyme. The new STCs were synthesised in good yields of > 85%, with a purity of about 95%, using a novel synthesis method by employing a reusable proline-proline dipeptide catalyst. The STCs are more potent than 6-shogaol in activating NRF2 and reducing inflammation. The nature of substituents on thiophene has a profound influence on the bioactivity of the STCs. Phenylthiophene STC (STC5) is the most potent, while thiophenes containing electron-withdrawing groups showed weaker bioactivity. The bioactivity of 6-shogaol is in the micromolar range, whereas STC5 showed bioactivity in the sub micromolar range. The STCs showed anti-inflammatory effects via NRF2-dependent and NRF2-independent mechanisms. The STCs improved NRF2 activity through multiple (KEAP1-independent and -dependent) mechanisms. The STCs showed decreased reactivity with thiols than 6-shogaol and thus may possess fewer side-effects than 6-shogaol. The STCs were more metabolically stable than 6-shogaol.

Synthesis and Anti-Inflammatory Activity of 2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-Derived NRF2 Activators.

This is the first study investigating the nuclear factor (erythroid-derived 2)-like 2 (NRF2) activity of compounds containing a new scaffold, tetrahydrobenzo[b]thiophene. Eighteen compounds were synthesised and confirmed their NRF2 activation through NQO1 enzymatic activity and mRNA expression of NQO1 and HO-1 in Hepa-1c1c7 cells. The compounds disrupted the interaction between Kelch-like ECH-associated protein 1 (KEAP1) and NRF2 via interfering with the KEAP1's Kelch domain. The compounds exhibited anti-inflammatory activity in Escherichia coli Lipopolysaccharide (LPSEc )-stimulated RAW 264.7 cells. The anti-inflammatory activity of the compounds was associated with their ability to activate NRF2. The compounds reversed the elevated levels of pro-inflammatory cytokines (IL-1ß, IL-6, TNF-α, and IFN-γ) and inflammatory mediators (PGE2, COX-2, and NF-κB). The compounds were metabolically stable in human, rat, and mouse liver microsomes and showed optimum half-life (T1/2 ) and intrinsic clearance (Clint ). The binding mode of the compounds and physicochemical properties were predicted via in silico studies.

Swietenine potentiates the antihyperglycemic and antioxidant activity of Metformin in Streptozotocin induced diabetic rats.

Diabetes mellitus or type-2 diabetes, commonly referred as diabetes, is a metabolic disorder that results in high blood sugar level. Despite the availability of several antidiabetic drugs in the market, they still do not adequately regulate blood sugar levels. Thus, in general people prefer to use herbal supplements/medicines along with antidiabetic drugs to control blood sugar levels. One of such herbal medicine is Swietenia macrophylla seeds. It is widely used in Asia for controlling blood sugar levels. One of the major bioactive compounds, Swietenine, is reported to be responsible for controlling blood glucose levels. However, there were no studies on its efficacy in controlling the blood glucose in diabetic rats. In this study, we evaluated the antihyperglycemic activity of Swietenine and its pharmacodynamic interaction with Metformin in Streptozotocin induced diabetes in rats. The activity of Swietenine was investigated at three different doses: 10, 20 and 40 mg/kg body weight (bw). Metformin (50 mg/kg bw) was used as a standard drug. Swietenine (20 and 40 mg/kg bw) and Metformin (50 mg/kg bw) showed significant effect in reducing the glucose, cholesterol, triglycerides, low-density lipoprotein, urea, creatinine, alanine transaminase, alkaline phosphatase, aspartate transaminase, alanine transaminase, and malondialdehyde level in serum while it had increased the high-density lipoprotein, glutathione, and total antioxidant capacity level. In addition, Swietenine (20 and 40 mg/kg) had shown significant synergistic effect with Metformin. Administration of Swietenine at 10 mg/kg bw neither showed activity nor influenced Metformin's activity. The results from this study confirmed the beneficial effects of Swietenine and its synergistic action with Metformin in controlling the dysregulated serum parameters in Streptozotocin induced diabetes in rats.

Decompressive craniectomy and mild hypothermia reduces infarction size and counterregulates Bax and Bcl-2 expression after permanent focal ischemia in rats.

Both mild hypothermia (MH) and decompressive craniectomy (CE) have been shown to have neuroprotective effects in brain ischemia. We investigated a possible effect of MH and a combination of CE and MH (CE + MH) on the changes of infarction size, DNA fragmentation, and immunoreactivities for Bcl-2 and Bax after 24 h of permanent middle cerebral artery occlusion (MCAO) in rats. For the estimation of ischemic brain injury, we calculated the infarct size of the MCA region at 24 h after the MCAO. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick labeling (TUNEL) staining was performed for the detection of DNA fragmentation. Immunoreactivities for Bcl-2 and Bax were stained. Infarction size after permanent MCAO was significantly reduced by CE+MH treatment (P < 0.01). Infarction size did not change significantly by application of MH alone (P > 0.05). TUNEL staining was remarkably reduced both in MH-treated animals and in CE + MH-treated animals. Immunoreactivity for Bcl-2 was greatly induced both in MH-treated animals and in CE + MH-treated animals. Induction of immunoreactivity for Bcl-2 was obviously inhibited both in MH-treated animals and in CE + MH-treated animals. It suggests that temporary MH delays infarct evolution and ameliorates neuron apoptosis but does not significantly reduce definite infarction size. CE + MH not only ameliorates neuron apoptosis but also remarkably reduces infarction size.