Food-related compounds that modulate expression of inducible nitric oxide synthase may act as its inhibitors

Black and pinto beans (Phaseolus vulgaris L.) unique mexican varieties exhibit antioxidant and anti-inflammatory potential

Oxidative stress and inflammation play a key role in diverse pathological conditions such as cancer and metabolic disorders. The objective of this study was to determine the antioxidant and anti-inflammatory potentials of crude extract (CE) and phenolic-enriched extract (PHE) obtained from the seed coats (SCs) of black bean (BB) and pinto bean (PB) varieties. Delphinidin-3-O-glucoside (46 mg/g SC), malvidin-3-O-glucoside (29.9 mg/g SC), and petunidin-3-O-glucoside (7.5 mg/g SC) were found in major concentrations in the PHE-BB. Pelargonidin (0.53 mg/g SC) was only identified in the PHE-PB. PHE from both varieties showed antioxidant and radical scavenging capacities, with strong correlations associated with total phenolic content (TPC). Polyphenolics, including catechin, myricetin, kaempferol, quercetin, and isorhamnetin glucosides, were identified in the extracts. In terms of the anti-inflammatory potentials, PHE-PB had an IC₅₀ of 10.5 µg dry extract/mL (µg DE/mL) for cyclooxygenase-2 (COX-2) inhibition. The inhibition values for cyclooxygenase-1 (COX-1) ranged from 118.1 to 162.7 µg DE/mL. Regarding inducible nitric oxide synthase (iNOS) inhibition, PHE-BB had an IC₅₀ of 62.6 µg DE/mL. As determined via in silico analysis, pelargonidin showed binding affinities of -7.8 and -8.5 kcal/mol for COX-1 and iNOS, respectively, and catechin had a value of -8.3 kcal/mol for COX-2. Phenolic-enriched extracts from seed coats of black and pinto beans showed good antioxidant and anti-inflammatory potential that warrants in vitro and in vivo studies.

Mexican Native Black Bean Anthocyanin-Rich Extracts Modulate Biological Markers Associated with Inflammation

This work aimed to obtain and characterize anthocyanin-rich extracts (ARE) from native black beans and evaluate their antioxidant and anti-inflammatory potential. The initial extract was obtained by supercritical fluids (RE) and purified using Amberlite^® XAD-7 resin (PE). RE and PE were fractionated using countercurrent chromatography, and four fractions were obtained (REF1 and REF2 from RE, PEF1, and PEF2 from PE). ARE and fractions were characterized, and the biological potential was evaluated. ABTS IC₅₀ values ranged from 7.9 to 139.2 (mg C3GE/L), DPPH IC₅₀ ranged from 9.2 to 117.2 (mg C3GE/L), and NO IC₅₀ ranged from 0.6 to143.8 (mg C3GE/L) (p < 0.05). COX-1 IC₅₀ ranged from 0.1 to 0.9 (mg C3GE/L), COX-2 IC₅₀ ranged from 0.01 to 0.7 (mg C3GE/L), and iNOS IC₅₀ ranged from 0.9 to 5.6 (mg C3GE/L) (p < 0.05). The theoretical binding energy for phenolic compounds ranged from -8.45 to -1.4 kcal/mol for COX-1, from -8.5 to -1.8 kcal/mol for COX-2, and from -7.2 to -1.6 kcal/mol for iNOS. RE and REF2 presented the highest antioxidant and anti-inflammatory potential. Countercurrent chromatography effectively isolates and purifies bioactive compounds while maintaining their biological potential. Native black beans present an attractive phytochemical profile and could be used as ingredients in nutraceuticals and functional foods.

Antioxidant and Anti-Inflammatory Capacities of Fractions and Constituents from Vicia tetrasperma

The young leaves and shoots of V. tetrasperma are consumed daily as cooked vegetables and can provide various health benefits. The antioxidant and anti-inflammatory capacities of its total extract and fractions were accessed for the first time in this study. The bioactivities guided the separation of the active fraction (EtOAc), leading to the identification of nine flavonoid glycoside compositions from this plant for the first time. In addition, the fractions and all isolates were evaluated for their inhibition against NO and IL-8 production in LPS-stimulated RAW264.7 and HT-29 cell lines, respectively. The most active ingredient was further assayed for its inhibitory abilities to iNOS and COX-2 proteins. Indeed, its mechanisms of action modes were confirmed by Western blotting assays through the reduction in their expression levels. An in silico approach revealed the substantial binding energies of docked compounds into established complexes to verify their anti-inflammatory properties. In addition, the presence of active components in the plant was validated by an established method on the UPLC-DAD system. Our research has boosted the value of this vegetable's daily use and provided a therapeutic approach for the development of functional food products for health improvement regarding the treatment of oxidation and inflammation.

Profile of Myracrodruon urundeuva Volatile Compounds Ease of Extraction and Biodegradability and In Silico Evaluation of Their Interactions with COX-1 and iNOS

Myracrodruon urundeuva Fr. Allem. (Anacardiaceae) is a tree popularly known as the "aroeira-do-sertão", native to the caatinga and cerrado biomes, with a natural dispersion ranging from the Northeast, Midwest, to Southeast Brazil. Its wood is highly valued and overexploited, due to its characteristics such as durability and resistance to decaying. The diversity of chemical constituents in aroeira seed has shown biological properties against microorganisms and helminths. As such, this work aimed to identify the profile of volatile compounds present in aroeira seeds. Headspace solid phase microextraction was employed (HS-SPME) using semi-polar polydimethylsiloxane-divinylbenzene fiber (PDMS/DVB) for the extraction of VOCs. 22 volatile organic compounds were identified: nine monoterpenes and eight sesquiterpenes, in addition to six compounds belonging to different chemical classes such as fatty acids, terpenoids, salicylates and others. Those that stood out were p-mentha-1,4, 4(8)-diene, 3-carene (found in all samples), caryophyllene and cis-geranylacetone. A virtual docking analysis suggested that around 65% of the VOCs molar content from the aroeiras seeds present moderate a strong ability to bind to cyclooxygenase I (COX-I) active site, oxide nitric synthase (iNOS) active site (iNOSas) or to iNOS cofactor site (iNOScs), corroborating an anti-inflamatory potential. A pharmacophoric descriptor analysis allowed to infer the more determinant characteristics of these compounds' conferring affinity to each site. Taken together, our results illustrate the high applicability for the integrated use of SPME, in silico virtual screening and chemoinformatics tools at the profiling of the biotechnological and pharmaceutical potential of natural sources.

Imatinib exhibit synergistic pleiotropy in the prevention of colorectal cancer by suppressing proinflammatory, cell survival and angiogenic signaling

Recent global incidences and mortality rates have placed colorectal cancer (CRC) at third and second positions, respectively, among both sexes of all ages. Resistance during chemotherapy is a big problem in the treatment and disease-free survival of CRC patients. Discovery of new anticancer drug(s) is a time taking process and therefore, invites studies for repurposing the known therapeutics. The present study was conceived to analyze the anticancer role of Imatinib in experimental CRC at early stages. Different experimental procedures e.g. tumor incidences or histoarchitectural changes, gene and protein expression analysis, estimations of intracellular calcium, ROS, mitochondrial membrane potential, apoptotic index and molecular docking was performed to support the hypothesis. It was observed that Imatinib could function as an immunomodulator by breaking the feed-back loop between the proinflammatory cytokines (IL-1β and TNF-α) and transcription factors (NF-κB, Jak3/Stat3) knowingly involved in increased cell proliferation during tumorigenesis via activating different intracellular signaling. Also, Imatinib could independently deregulate the other cell survival and proliferation signaling e.g. PI3-K/Akt/mTOR, Wnt/β-catenin and MAPK. Proinflammatory cytokines orchestrated intracellular signaling also involve angiogenic factors to be upregulated during CRC which were also seemed to be independently suppressed by Imatinib. Restoration of physiological apoptosis by increasing the release of intracellular calcium to generate ROS thereby reducing the mitochondrial membrane potential for the release of cytochrome c and activation of caspase-3 was also reported with Imatinib administration. Thus, it may be suggested that Imatinib show synergistic pleiotropy in suppressing the interlinked tumorigenic signaling pathways independently.

Interventions of natural and synthetic agents in inflammatory bowel disease, modulation of nitric oxide pathways

Inflammatory bowel disease (IBD) refers to a group of disorders characterized by chronic inflammation of the gastrointestinal (GI) tract. The elevated levels of nitric oxide (NO) in serum and affected tissues; mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme; can exacerbate GI inflammation and is one of the major biomarkers of GI inflammation. Various natural and synthetic agents are able to ameliorate GI inflammation and decrease iNOS expression to the extent comparable with some IBD drugs. Thereby, the purpose of this study was to gather a list of natural or synthetic mediators capable of modulating IBD through the NO pathway. Electronic databases including Google Scholar and PubMed were searched from 1980 to May 2018. We found that polyphenols and particularly flavonoids are able to markedly attenuate NO production and iNOS expression through the nuclear factor κB (NF-κB) and JAK/STAT signaling pathways. Prebiotics and probiotics can also alter the GI microbiota and reduce NO expression in IBD models through a broad array of mechanisms. A number of synthetic molecules have been found to suppress NO expression either dependent on the NF-κB signaling pathway (i.e., dexamethasone, pioglitazone, tropisetron) or independent from this pathway (i.e., nicotine, prednisolone, celecoxib, β-adrenoceptor antagonists). Co-administration of natural and synthetic agents can affect the tissue level of NO and may improve IBD symptoms mainly by modulating the Toll like receptor-4 and NF-κB signaling pathways.

The gastroprotective potential of silibinin against Helicobacter pylori infection and gastric tumor cells

AIMS

Silibinin is the major component of flavonolignans complex mixture (Silymarin), which is obtained from Silybum marianum (L.) Gaertn. Despite several reports about silibinin, little is known about its effects on gastric diseases. Then, the present study aims to evaluate the silibinin effect against Helicobacter pylori infection, gastric tumor cells and immunomodulation.

MAIN METHODS

The anti-H. pylori effect was performed on 43504 and 43629 strains by minimum inhibitory concentration (MIC) determination, observing morphological alterations by scanning electron microscopy and in silico evaluation by molecular docking. Immunomodulatory activity (Interleukins-6 and 10, TNF-α and NO inhibition) was determined in H. pylori-stimulated macrophages and the cytotoxic activity on gastric adenocarcinoma cells prior and after metabolization by S9 fraction.

KEY FINDINGS

Silibinin showed anti-H. pylori activity with MIC of 256 μg/mL, promoted important morphological changes in the bacterial cell wall, as blebs and clusters, suggesting interaction with Penicillin Binding Protein (PBP) subunits. Immunomodulatory potential was observed at 50 μg/mL with the inhibition of produced cytokines and NO by H. pylori-stimulated macrophages of 100% for TNF-ɑ, 56.83% for IL-6, and 70.29% for IL-10 and 73.33% for NO. Moreover, silibinin demonstrated significant cytotoxic activity on adenocarcinoma cells (CI₅₀: 60.17 ± 0.95 μg/mL) with a higher selectivity index (SI: 1.52) compared to cisplatin. After metabolization silibinin showed an increase of cytotoxicity with a CI₅₀ six-fold decrease (10.46 ± 0.25).

SIGNIFICANCE

The use of silibinin may become an important alternative tool in the prevention and treatment of H. pylori infection and, consequently, in gastric cancer.

In silico evaluation of pesticides as potential modulators of human DNA methyltransferases

DNA methylations are carried out by DNA methyltransferases (DNMTs) that are key enzymes during gene expression. Many chemicals, including pesticides, have shown modulation of epigenetic functions by inhibiting DNMTs. In this work, human DNMTs were evaluated as a potential target for pesticides through virtual screening of 1038 pesticides on DNMT1 (3SWR) and DNMT3A (2QRV). Molecular docking calculations for DNMTs-pesticide complexes were performed using AutoDock Vina. Binding-affinity values and contact patterns were employed as selection criteria of pesticides as virtual hits for DNMTs. The best three DNMT-pesticides complexes selected according to their high absolute affinity values (kcal/mol), for both DNMT1 and DNMT3A, were flocoumafen (-12.5; -9.9), brodifacoum (-12.4; -8.4) and difenacoum (-12.1; -8.7). These chemicals belong to second-generation rodenticides. The most frequent predicted interacting residues for DNMT1-pesticide complexes were Trp1170A, Phe1145A, Asn1578A, Arg1574A and Pro1225A; whereas for DNMT3A those were Arg271B, Lys740A, and Glu303B. These results suggest that rodenticides used for pest control are potential DNMT ligands and therefore, may modulate DNA methylations. This finding has important environmental and clinical implications, as epigenetic pathways are critical in many biochemical processes leading to diseases.

Natural Products as Chemopreventive Agents by Potential Inhibition of the Kinase Domain in ErbB Receptors

Small molecules found in natural products provide therapeutic benefits due to their pharmacological or biological activity, which may increase or decrease the expression of human epidermal growth factor receptor (HER), a promising target in the modification of signaling cascades involved in excessive cellular growth. In this study, in silico molecular protein-ligand docking protocols were performed with AutoDock Vina in order to evaluate the interaction of 800 natural compounds (NPs) from the NatProd Collection (http://www.msdiscovery.com/natprod.html), with four human HER family members: HER1 (PDB: 2ITW), HER2 (PDB: 3PP0), HER3 (PDB: 3LMG) and HER4 (PDB: 2R4B). The best binding affinity values (kcal/mol) for docking pairs were obtained for HER1-podototarin (−10.7), HER2-hecogenin acetate (−11.2), HER3-hesperidin (−11.5) and HER4-theaflavin (−10.7). The reliability of the theoretical calculations was evaluated employing published data on HER inhibition correlated with in silico binding calculations. IC₅₀ values followed a significant linear relationship with the theoretical binding Affinity data for HER1 (R = 0.656, p < 0.0001) and HER2 (R = 0.543, p < 0.0001), but not for HER4 (R = 0.364, p > 0.05). In short, this methodology allowed the identification of several NPs as HER inhibitors, being useful in the discovery and design of more potent and selective anticancer drugs.

Mechanisms of interaction between persistent organic pollutants (POPs) and CYP2B6: An in silico approach

Human Cytochrome P450s (CYP450) are a group of heme-containing metalloenzymes responsible for recognition and metabolism of numerous xenobiotics, including drugs and environmental contaminants. CYP2B6, a member of CYP450, is well known for being a highly inducible and polymorphic enzyme and for its important role in the oxidative metabolism of environmental pollutants, such as the Polybrominated Diphenyl Ethers (PBDEs) and Polychlorinated Biphenyls (PCBs). However the mechanisms of interaction of PBDEs and PCBs with CYP2B6 is not entirely known. In this work, a computational approach was carried out to study the interactions of 41 POPs (17 PBDEs, 17 PCBs, and 7 Dioxins) with four CYP2B6 protein structures downloaded from PDB data base (PDB: 3UA5, 3QOA, 3QU8 and 4I91) using molecular docking protocols with AutoDock Vina. The best binding affinity values (kcal/mol) were obtained for PBDE-99 (-8.5), PCB-187 (-9.6), and octachloro-dibenzo-dioxin (-9.8) that can be attributed to the hydrophobic interactions with important residues, such as Phe-363, in the catalytic site of CYP2B6. Molecular docking validation revealed the best values for PDB: 3UA5 (R = 0.622, p = 0.001) demonstrating the reliability of molecular docking predictions. The information obtained in this work can be useful in evaluating the modes of interaction of xenobiotic compounds with the catalytic site of CYP2B6 and provide insights on the important role of these enzymes in the metabolism of potentially toxic compounds in humans.

Urban Endocrine Disruptors Targeting Breast Cancer Proteins

Humans are exposed to a huge amount of environmental pollutants called endocrine disrupting chemicals (EDCs). These molecules interfere with the homeostasis of the body, usually through mimicking natural hormones leading to activation or blocking of their receptors. Many of these compounds have been associated with a broad range of diseases including the development or increased susceptibility to breast cancer, the most prevalent cancer in women worldwide, according to the World Health Organization. Thus, this article presents a virtual high-throughput screening (vHTS) to evaluate the affinity of proteins related to breast cancer, such as ESR1, ERBB2, PGR, BCRA1, and SHBG, among others, with EDCs from urban sources. A blind docking strategy was employed to screen each protein-ligand pair in triplicate in AutoDock Vina 2.0, using the computed binding affinities as ranking criteria. The three-dimensional structures were previously obtained from EDCs DataBank and Protein Data Bank, prepared and optimized by SYBYL X-2.0. Some of the chemicals that exhibited the best affinity scores for breast cancer proteins in each category were 1,3,7,8-tetrachlorodibenzo-p-dioxin, bisphenol A derivatives, perfluorooctanesulfonic acid, and benzo(a)pyrene, for catalase, several proteins, sex hormone-binding globulin, and cytochrome P450 1A2, respectively. An experimental validation of this approach was performed with a complex that gave a moderate binding affinity in silico, the sex hormone binding globulin (SHBG), and bisphenol A (BPA) complex. The protein was obtained using DNA recombinant technology and the physical interaction with BPA assessed through spectroscopic techniques. BPA binds on the recombinant SHBG, and this results in an increase of its α helix content. In short, this work shows the potential of several EDCs to bind breast cancer associated proteins as a tool to prioritize compounds to perform in vitro analysis to benefit the regulation or exposure prevention by the general population.

Computational fishing of new DNA methyltransferase inhibitors from natural products

DNA methyltransferase inhibitors (DNMTis) have become an alternative for cancer therapies. However, only two DNMTis have been approved as anticancer drugs, although with some restrictions. Natural products (NPs) are a promising source of drugs. In order to find NPs with novel chemotypes as DNMTis, 47 compounds with known activity against these enzymes were used to build a LDA-based QSAR model for active/inactive molecules (93% accuracy) based on molecular descriptors. This classifier was employed to identify potential DNMTis on 800 NPs from NatProd Collection. 447 selected compounds were docked on two human DNA methyltransferase (DNMT) structures (PDB codes: 3SWR and 2QRV) using AutoDock Vina and Surflex-Dock, prioritizing according to their score values, contact patterns at 4 Å and molecular diversity. Six consensus NPs were identified as virtual hits against DNMTs, including 9,10-dihydro-12-hydroxygambogic, phloridzin, 2',4'-dihydroxychalcone 4'-glucoside, daunorubicin, pyrromycin and centaurein. This method is an innovative computational strategy for identifying DNMTis, useful in the identification of potent and selective anticancer drugs.

2,2'-diphenyl-3,3'-diindolylmethane: a potent compound induces apoptosis in breast cancer cells by inhibiting EGFR pathway

Despite recent advances in medicine, 30-40% of patients with breast cancer show recurrence underscoring the need for improved effective therapy. In this study, by in vitro screening we have selected a novel synthetic indole derivative 2,2'-diphenyl-3,3'-diindolylmethane (DPDIM) as a potential anti- breast cancer agent. DPDIM induces apoptosis both in vitro in breast cancer cells MCF7, MDA-MB 231 and MDA-MB 468 and in vivo in 7,12-dimethylbenz[α]anthracene (DMBA) induced Sprague-Dawley (SD) rat mammary tumor. Our in vitro studies show that DPDIM exerts apoptotic effect by negatively regulating the activity of EGFR and its downstream molecules like STAT3, AKT and ERK1/2 which are involved in the proliferation and survival of these cancer cells. In silico predictions also suggest that DPDIM may bind to EGFR at its ATP binding site. DPDIM furthermore inhibits EGF induced increased cell viability. We have also shown decreased expression of pro-survival factor Bcl-XL as well as increase in the level of pro-apoptotic proteins like Bax, Bad, Bim in DPDIM treated cells in vitro and in vivo. Our results further indicate that the DPDIM induced apoptosis is mediated through mitochondrial apoptotic pathway involving the caspase-cascade. To the best of our knowledge this is the first report of DPDIM for its anticancer activity. Altogether this report suggests that DPDIM could be an effective therapeutic agent for breast cancer.