Antiulcerogenic activity of Terminalia chebula fruit in experimentally induced ulcer in rats

Objective: The present study is to evaluate the antiulcer effect of hydroalcoholic (70%) extract of Terminalia chebula fruit. Materials and methods: Aspirin, ethanol and cold restraint stress-induced ulcer methods in rats were used for the study. The effects of the extract on gastric secretions, pH, total and free acidity using pylorus ligated methods were also evaluated. Results: Animals pretreated with doses of 200 and 500 mg/kg hydroalcoholic extract showed significant reduction in lesion index, total affected area and percentage of lesion in comparison with control group (P < 0.05 and P < 0.01) in the aspirin, ethanol and cold restraint stress-induced ulcer models. Similarly extracts increased mucus production in aspirin and ethanol-induced ulcer models. At doses of 200 and 500 mg/kg of T. chebula extract showed antisecretory activity in pylorus ligated model, which lead to a reduction in the gastric juice volume, free acidity, total acidity, and significantly increased gastric pH. Discussion and conclusion: These findings indicate that hydroalcoholic extract of the fruit T. chebula displays potential antiulcerogenic activity. This activity thus lends pharmacological credence to the suggested use of the plant as a natural remedy in the treatment or management of ulcer.

Metabolism of 1,8-Cineole in Rat: Its Effects on Liver and Lung Microsomal Cytochrome P-450 Systems

The monoterpene cyclic ether, cineole (l,8-cineole, I) also known as eucalyptol, is a component of many essential oils and is widely distributed in nature. It is extensively used in pharmaceutical preparations for external application and also as a nasal spray. It was reported earlier that cineole when administered to sheep may be largely oxidized in the system (Scheline 1978). However the mode of metabolism of cineole is not known. Hence the present study was undertaken to investigate the metabolic fate of this ubiquitous terpenoid following its administration to rats by gastric intubation.

Prediction of protein-protein interactions between Helicobacter pylori and a human host

A lack of information on protein-protein interactions at the host-pathogen interface is impeding the understanding of the pathogenesis process. A recently developed, homology search-based method to predict protein-protein interactions is applied to the gastric pathogen, Helicobacter pylori to predict the interactions between proteins of H. pylori and human proteins in vitro. Many of the predicted interactions could potentially occur between the pathogen and its human host during pathogenesis as we focused mainly on the H. pylori proteins that have a transmembrane region or are encoded in the pathogenic island and those which are known to be secreted into the human host. By applying the homology search approach to protein-protein interaction databases DIP and iPfam, we could predict in vitro interactions for a total of 623 H. pylori proteins with 6559 human proteins. The predicted interactions include 549 hypothetical proteins of as yet unknown function encoded in the H. pylori genome and 13 experimentally verified secreted proteins. We have recognized 833 interactions involving the extracellular domains of transmembrane proteins of H. pylori. Structural analysis of some of the examples reveals that the interaction predicted by us is consistent with the structural compatibility of binding partners. Examples of interactions with discernible biological relevance are discussed.

Enhanced Survival of Probiotic Lactobacillus acidophilus by Encapsulation with Nanostructured Polyelectrolyte Layers through Layer-by-Layer Approach

The encapsulation of probiotic Lactobacillus acidophilus through layer-by-layer self-assembly of polyelectrolytes (PE) chitosan (CHI) and carboxymethyl cellulose (CMC) has been investigated,to enhance its survival m adverse conditions encountered in the GI tract The survival of encapsulated cells in simulated gastric (SGF) and intestinal fluids (SIF) is significant when compared to nonencapsulated cells On sequential exposure to SGF and SIF fox 120 nun, almost complete death of free cells is observed However, for cells coated with three nanolayers of PEs (CHI/CMC/CHI) about 33 log % of the cells (6 log cfu/500 mg) survived under the same conditions The enhanced survival rate of encapsulated L acidophilus can be attributed to the impermeability of polyelectrolyte nanolayers to large enzyme molecules like pepsin, and pancreatin that cause proteolysis and to the stability of the polyelectrolyte nanolayers in gastric and intestinal pH The PE coating also serves to reduce viability losses during freezing and freeze- drying About 73 and 92 log % of uncoated and coated cells survived after freeze:drying, and the losses occurring between freezing and freeze-drying were found to be lower for coated cells

Molecular Docking Studies of Novel Palmitoyl-ligands for Cyclooxygenase-2

An in silico approach was adopted to identify potential cyclooxygenase-2 inhibitors through molecular docking studies. The in vivo studies indicated that synthetic palmitoyl derivatives of salicylic acid, para amino phenol, para amino benzoic acid, and anthranilic acid possessed significant pharmacological activities like anti-inflammatory, analgesic, and antipyretic activities. None of the tested substances produced any significant gastric lesions in experimental animals. In an attempt to understand the ligandprotein interactions in terms of the binding affinity, the above synthetic molecules were subjected to docking analysis using AutoDock. The palmitoyl derivatives palmitoyl anthranilic acid, palmitoyl para amino benzoic acid, palmitoyl para amino phenol, and palmitoyl salicylic acid showed better binding energy than the known inhibitor diclofenac bound to 1PXX. All the palmitoyl derivatives made similar interactions with the binding site residues of cyclooxygenase-2 as compared to that of the known inhibitor. Thus, structure-based drug discovery approach was successfully employed to identify some promising pro-drugs for the treatment of pain and inflammation.

Acidic pH induced STM1485 gene is essential for intracellular replication of Salmonella

During the course of infection, Salmonella has to face several potentially lethal environmental conditions, one such being acidic pH. The ability to sense and respond to the acidic pH is crucial for the survival and replication of Salmonella. The physiological role of one gene (STM1485) involved in this response, which is upregulated inside the host cells (by 90- to 113-fold) is functionally characterized in Salmonella pathogenesis. In vitro, the DSTM1485 neither exhibited any growth defect at pH 4.5 nor any difference in the acid tolerance response. The DSTM1485 was compromised in its capacity to proliferate inside the host cells and complementation with STM1485 gene restored its virulence. We further demonstrate that the surface translocation of Salmonella pathogenicity island-2 (SPI-2) encoded translocon proteins, SseB and SseD were reduced in the DSTM1485. The increase in co-localization of this mutant with lysosomes was also observed. In addition, the DSTM1485 displayed significantly reduced competitive indices (CI) in spleen, liver and mesenteric lymph nodes in murine typhoid model when infected by intra-gastric route. Based on these results, we conclude that the acidic pH induced STM1485 gene is essential for intracellular replication of Salmonella.

Infrared Spectroscopic Studies to Understand the Effect of Drugs at Molecular Level

In the recent past, there have been enormous efforts to understand effect of drugs on human body. Prior to understand the effect of drugs on human body most of the experiments are carried out on cells or model organisms. Here we present our study on the effect of chemotherapeutic drugs on cancer cells and the acetaminophen (APAP) induced hepatotoxicity in mouse model. Histone deacetylase inhibitors (HDIs) have attracted attention as potential drug molecules for the treatment of cancer. These are the chemotherapeutic drugs which have indirect mechanistic action against cancer cells via acting against histone deacetylases (HDAC). It has been known that different HDAC enzymes are over-expressed in various types of cancers for example; HDAC1 is over expressed in prostate, gastric and breast carcinomas. Therefore, in order to optimise chemotherapy, it is important to determine the efficacy of various classes of HDAC inhibitor drugs against variety of over-expressed HDAC enzymes. In the present study, FTIR microspectroscopy has been employed to predict the acetylation and propionylation brought in by HDIs. The liver plays an important role in cellular metabolism and is highly susceptible to drug toxicity. APAP which is an analgesic and antipyretic drug is extensively used for therapeutic purposes and has become the most common cause of acute liver failure (ALF). In the current study, we have focused to understand APAP induced hepatotoxicity using FTIR microspectroscopy. In the IR spectrum the bands corresponding to glycogen, ester group and were found to be suitable markers to predict liver injury at early time point (0.5hr) due to APAP both in tissue and serum in comparison to standard biochemical assays. Our studies show the potential of FTIR spectroscopy as a rapid, sensitive and non invasive detection technique for future clinical diagnosis.

Oncogenic MicroRNA-155 Down-regulates Tumor Suppressor CDC73 and Promotes Oral Squamous Cell Carcinoma Cell Proliferation IMPLICATIONS FOR CANCER THERAPEUTICS

The CDC73 gene is mutationally inactivated in hereditary and sporadic parathyroid tumors. It negatively regulates beta-catenin, cyclin D1, and c-MYC. Down-regulation of CDC73 has been reported in breast, renal, and gastric carcinomas. However, the reports regarding the role of CDC73 in oral squamous cell carcinoma (OSCC) are lacking. In this study we show that CDC73 is down-regulated in a majority of OSCC samples. We further show that oncogenic microRNA-155 (miR-155) negatively regulates CDC73 expression. Our experiments show that the dramatic up-regulation of miR-155 is an exclusive mechanism for down-regulation of CDC73 in a panel of human cell lines and a subset of OSCC patient samples in the absence of loss of heterozygosity, mutations, and promoter methylation. Ectopic expression of miR-155 in HEK293 cells dramatically reduced CDC73 levels, enhanced cell viability, and decreased apoptosis. Conversely, the delivery of a miR-155 antagonist (antagomir-155) to KB cells overexpressing miR-155 resulted in increased CDC73 levels, decreased cell viability, increased apoptosis, and marked regression of xenografts in nude mice. Cotransfection of miR-155 with CDC73 in HEK293 cells abrogated its pro-oncogenic effect. Reduced cell proliferation and increased apoptosis of KB cells were dependent on the presence or absence of the 3'-UTR in CDC73. In summary, knockdown of CDC73 expression due to overexpression of miR-155 not only adds a novelty to the list of mechanisms responsible for its down-regulation in different tumors, but the restoration of CDC73 levels by the use of antagomir-155 may also have an important role in therapeutic intervention of cancers, including OSCC.

Helicobacter pylori DprA alleviates restriction barrier for incoming DNA

Helicobacter pylori is a Gram-negative bacterium that colonizes human stomach and causes gastric inflammation. The species is naturally competent and displays remarkable diversity. The presence of a large number of restriction-modification (R-M) systems in this bacterium creates a barrier against natural transformation by foreign DNA. Yet, mechanisms that protect incoming double-stranded DNA (dsDNA) from restriction enzymes are not well understood. A DNA-binding protein, DNA Processing Protein A (DprA) has been shown to facilitate natural transformation of several Gram-positive and Gram-negative bacteria by protecting incoming single-stranded DNA (ssDNA) and promoting RecA loading on it. However, in this study, we report that H. pylori DprA (HpDprA) binds not only ssDNA but also dsDNA thereby conferring protection to both from various exo-nucleases and Type II restriction enzymes. Here, we observed a stimulatory role of HpDprA in DNA methylation through physical interaction with methyltransferases. Thus, HpDprA displayed dual functional interaction with H. pylori R-M systems by not only inhibiting the restriction enzymes but also stimulating methyltransferases. These results indicate that HpDprA could be one of the factors that modulate the R-M barrier during inter-strain natural transformation in H. pylori.

Enhanced viability of probiotic Saccharomyces boulardii encapsulated by layer-by-layer approach in pH responsive chitosan-dextran sulfate polyelectrolytes

Saccharomyces boulardii was encapsulated by layer-by-layer technique (LbL) using oppositely charged polyelectrolytes, chitosan and dextran sulfate to protect from degradation during its gastrointestinal transit. The protective effect of the coating was evaluated by checking viability after subjecting the coated cells to lyophilisation and simulated gastrointestinal conditions. During lyophilization, coated S. boulardii was found to have an enhanced viability of 7.74 +/- 2.00 log CFU/100 mg (5.62 x 10(6) +/- 2.12 CFU/100 mg) and 5.53 +/- 1.85 log CFU/100 mg (3.46 x 10(5) 1.73 CFU/100 mg) for uncoated cells. On sequential treatment with simulated gastric and intestinal juice, the coated cells had a viability of 4.59 +/- 1.52 log CFU/100 mg (3.8 x 104 +/- 1.52 CFU/100 mg) while only 1.90 +/- 0.80 log CFU/100 mg (0.79 x 102 +/- 0.81 CFU/100 mg) of uncoated cells survived. Confocal studies displayed the selective permeability of the coated cells which plays a significant role in maintaining the integrity and viability of the yeast cells. This clearly indicates that LbL is an efficient protective encapsulation technique and it could be potentially used for improving therapeutic applications of yeast. (C) 2014 Elsevier Ltd. All rights reserved.

Photonic monitoring of chitosan nanostructured alginate microcapsules for drug release

By using a novel microfluidic set-up for drug screening applications, this study examines delivery of a novel risedronate based drug formulation for treatment of osteoporosis that was developed to overcome the usual shortcomings of risedronate, such as its low bioavailability and adverse gastric effects. Risedronate nanoparticles were prepared using muco-adhesive polymers such as chitosan as matrix for improving the intestinal cellular absorption of risedronate and also using a gastric-resistant polymer such as sodium alginate for reducing the gastric inflammation of risedronate. The in-vitro characteristics of the alginate encapsulated chitosan nanoparticles are investigated, including their stability, muco-adhesiveness, and Caco-2 cell permeability. Fluorescent markers are tagged with the polymers and their morphology within the microcapsules is imaged at various stages of drug release.

The nuclease activities of both the Smr domain and an additional LDLK motif are required for an efficient anti-recombination function of Helicobacter pyloriMutS2

Helicobacter pylori, a human pathogen, is a naturally and constitutively competent bacteria, displaying a high rate of intergenomic recombination. While recombination events are essential for evolution and adaptation of H.pylori to dynamic gastric niches and new hosts, such events should be regulated tightly to maintain genomic integrity. Here, we analyze the role of the nuclease activity of MutS2, a protein that limits recombination during transformation in H.pylori. In previously studied MutS2 proteins, the C-terminal Smr domain was mapped as the region responsible for its nuclease activity. We report here that deletion of Smr domain does not completely abolish the nuclease activity of HpMutS2. Using bioinformatics analysis and mutagenesis, we identified an additional and novel nuclease motif (LDLK) at the N-terminus of HpMutS2 unique to Helicobacter and related epsilon-proteobacterial species. A single point mutation (D30A) in the LDLK motif and the deletion of Smr domain resulted in approximate to 5-10-fold loss of DNA cleavage ability of HpMutS2. Interestingly, the mutant forms of HpMutS2 wherein the LDLK motif was mutated or the Smr domain was deleted were unable to complement the hyper-recombination phenotype of a mutS2(-) strain, suggesting that both nuclease sites are indispensable for an efficient anti-recombinase activity of HpMutS2.