Kapil Upadhyay

Naturally Occurring Nrf2 Activators: Potential in Treatment of Liver Injury

Oxidative stress plays a major role in acute and chronic liver injury. In hepatocytes, oxidative stress frequently triggers antioxidant response by activating nuclear erythroid 2-related factor 2 (Nrf2), a transcription factor, which upregulates various cytoprotective genes. Thus, Nrf2 is considered a potential therapeutic target to halt liver injury. Several studies indicate that activation of Nrf2 signaling pathway ameliorates liver injury. The hepatoprotective potential of naturally occurring compounds has been investigated in various models of liver injuries. In this review, we comprehensively appraise various phytochemicals that have been assessed for their potential to halt acute and chronic liver injury by enhancing the activation of Nrf2 and have the potential for use in humans.

In vitro apoptosis-inducing effect and gene expression profiles of mixed ligand Cu(II) complexes derived from 4-acyl pyrazolones on human lung cancer cells

In order to study the less understood anti-tumor mechanism of pyrazolone based mixed ligand complexes, four Cu(II) mixed ligand complexes [Cu(L1)(Phen)NO3] (1), [Cu(L2)(Bipy)NO3] (2), [Cu(L2)(Phen)NO3] (3) and [Cu(L2)(Bipy)NO3] (4) [L1 = 3-methyl-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazole-4-carbaldehyde; L2 = 4-(1-naphthoyl)-3-methyl-1-(p-tolyl)-1H-pyrazol-5(4H)-one] have been synthesized and fully characterized. Single crystal X-ray diffraction analysis of three complexes indicated mononuclear structures exhibiting square pyramidal geometries. The inhibitory effects of the complexes on the cell population growth of the human lung carcinoma (A549) and human lung epithelial cell lines (L132) were determined by MTT assay, DAPI staining and DCFDA staining, which assessed mitochondrial dysfunction, nuclear condensation and intracellular oxidative stress, respectively. The expression levels of Bax (pro-apoptotic) and BCl2 (anti-apoptotic) genes were also studied in A549 cells wherein, both genes showed moderate downregulation after treatment with all the test complexes.

Apoptotic potential of C-phycoerythrin from Phormidium sp. A27DM and Halomicronema sp. A32DM on human lung carcinoma cells

Phycobilisomes present in cyanobacteria are photosynthetic macromolecular protein complexes that are categorized into three types - phycoerythrins (high energy), phycocyanin (intermediate energy) and allophycocyanin (low energy). Structurally, they consist of α and β protein subunits and open chain tetrapyrrole prosthetic group (bilin chromophore), known for its antioxidant properties and therapeutic potential against a variety of physiological ailments. Phycoerythrins (C-PE) were purified from cyanobacterial strains Phormidium sp. A27DM and Halomicronema sp. A32DM and their respective apoptotic potentials were assessed on A549 human lung carcinoma cells. Both strains of cyanobacteria were cultured and the C-PE from each strain was extracted, quantified and characterized. C-PE accounted for a dose dependent decrement in cell viability, mitochondrial membrane potential and an increment in lactate dehydrogenase release. Higher doses of C-PE (of both strains) accounted for loss of cell viability and nuclear pycnosis. These findings were further substantiated with flow cytometry that revealed a cell arrest at G0/G1 phase and a high percentage of cells undergoing apoptosis following C-PE treatment. These results confirm the efficacy of C-PE from Phormidium sp. or Halomicronema sp. in triggering apoptotic cell death. This study is the first to report on apoptotic property of C-PE against A549 human lung carcinoma cells and warrants further studies to establish its anti-cancer potential.

Carbon monoxide releasing molecule A-1 attenuates acetaminophen-mediated hepatotoxicity and improves survival of mice by induction of Nrf2 and related genes

&NA; Acute liver injury is frequently associated with oxidative stress. Here, we investigated the therapeutic potential of carbon monoxide releasing molecule A‐1 (CORM A‐1) in oxidative stress‐mediated liver injury. Overnight‐fasted mice were injected with acetaminophen (APAP; 300 mg/kg; intraperitoneally) and were sacrificed at 4 and 12 h. They showed elevated levels of serum transaminases, depleted hepatic glutathione (GSH) and hepatocyte necrosis. Mice injected with CORM A‐1 (20 mg/kg) 1 h after APAP administration, had reduced serum transaminases, preserved hepatic GSH and reduced hepatocyte necrosis. Mice that received a lethal dose of APAP (600 mg/kg), died by 10 h; but those co‐treated with CORM A‐1 showed a 50% survival. Compared to APAP‐treated mice, livers from those co‐treated with CORM A‐1, had upregulation of Nrf2 and ARE genes (HO‐1, GCLM and NQO‐1). APAP‐treated mice had elevated hepatic mRNA levels of inflammatory genes (Nf‐&kgr;B, TNF‐&agr;, IL1‐&bgr; and IL‐6), an effect blunted in those co‐treated with CORM A‐1. In tert‐butyl hydroperoxide (t‐BHP)‐treated HepG2 cells, CORM A‐1 augmented cell viability, reduced oxidative stress, activated the nuclear factor erythroid 2–related factor 2 (Nrf2) and anti‐oxidant response element (ARE) genes. The molecular docking profile of CO in the kelch domain of Keap1 protein suggested that CO released from CORM A‐1 mediated Nrf2 activation. Collectively, these data indicate that CORM A‐1 reduces oxidative stress by upregulating Nrf2 and related genes, and restoring hepatic GSH, to reduce hepatocyte necrosis and thus minimize liver injury that contributes to an overall improved survival rate. Graphical abstract Figure. No caption available. HighlightsCORM A‐1 treatment improved cell viability and intracellular oxidative stress.CORM A‐1 induced Nrf2 translocation in HepG2 cells and APAP induced hepatotoxicity.CORM A‐1 prevented APAP induced hepatic necrosis and improved survival rate.CO docks with Keap1 protein as evidenced by docking studies.

Anthocyanin rich extract of Brassica oleracea L. alleviates experimentally induced myocardial infarction

Cardioprotective potential of anthocyanin rich red cabbage extract (ARCE) was assessed in H2O2 treated rat neonatal cardiomyoblasts (H9c2 cells) and isoproterenol (ISO) induced rodent model of myocardial infarction. H2O2 treated H9c2 cells recorded cytotoxicity (48–50%) and apoptosis (57.3%), the same were reduced in presence of ARCE (7–10% & 12.3% respectively). Rats pretreated with ARCE for 30 days followed by ISO treatment recorded favourable heart: body weight ratio as compared to ISO treated group. Also, the mRNA levels of enzymatic antioxidants (sod and catalase) and apoptotic genes (bax and bcl-2) in ARCE+ISO treated group were similar to the control group suggesting that ARCE pretreatment prevents ISO induced depletion of enzymatic antioxidants and apoptosis. Histoarchitecture of ventricular tissue of ISO treated group was marked by infracted areas (10%) and derangement of myocardium whereas, ARCE+ISO treated group (4.5%) recorded results comparable to control (0%). ARCE+ISO treated group accounted for upregulation of caveolin-3 and SERCA2a expression as compared to the ISO treated group implying towards ARCE mediated reduction in membrane damage and calcium imbalance. Molecular docking scores and LigPlot analysis of cyanidin-3-glucoside (-8.7 Kcal/mol) and delphinidin-3-glucoside (-8.5 Kcal/mol) showed stable hydrophobic and electrostatic interactions with β1 adrenergic receptor. Overall this study elucidates the mechanism of ARCE mediated prevention of experimentally induced myocardial damage.