Glucose Ester Research Articles

Molecular cloning of a putative Acanthus ebracteatus- 9-cis-epoxycarotenoid deoxygenase (AeNCED) and its overexpression in rice

9-Cis-epoxycarotenoid dioxygenase (NCED) is an important enzyme which catalyzes the oxidative cleavage of abscisic acid (ABA), a plant growth regulator which plays a vital role in stress tolerance. In this study, a cDNA sequence encoding NCED from a mangrove plant (Acanthus ebracteatus) was analyzed and overexpressed in rice. Analysis of the deduced amino acid sequence of AeNCED revealed an open reading frame of 1,638 bp encoding a protein of 545 amino acids, with a 123 bp 5’-untranslated region (UTR) and a 259 bp 3’-UTR. The deduced amino acid sequence of AeNCED is more than 80% identical to the amino acid sequences of carotenoid cleavage dioxygenase from carrot, tomato, and coffee. The RNA encoding AeNCED was detected in transgenic rice (Oryza sativa cv. BRRI dhan29) plants overexpressing this cDNA. These plants only showed significantly higher tolerance to salinity at germination and better performance at seedling stages. The levels of ABA in transgenic rice seedlings overexpressing AeNCED treated with 100 mM NaCl for 24 hours were higher than those of untransformed plants. However, a higher level of dihydrophaseic acid (DPA) and ABA glucose ester (ABA-GE) were also observed in these transgenic plants suggesting that rapid degradation of ABA through a self-regulation mechanism.

English

The aim of this study was to quantify and evaluate the antibacterial activity of tannins extracted from leaves of Psidium guineense, obtained using two different isolation methods, against Staphylococcus aureus and Pseudomonas aeruginosa. The first extraction method was used to isolate condensed tannins (Method A) and the second to isolate mixtures rich in esters of gallic acid and glucose (Method B). Both extraction methods yielded high concentrations of tannins, with 312 and 257 mg/g of dry material obtained using Methods A and B, respectively. These compounds formed halos of growth inhibition in S. aureus and P. aeruginosa cultures. Tannins isolated by method B gave rise to larger inhibition halos than those isolated by method A. Analysis of the antibacterial activity of tannins isolated by method B revealed a minimum inhibitory and bactericidal concentration of 256 μg/ml for S. aureus and 512 μg/ml for P. aeruginosa. These results demonstrate that P. guineense is a promising source of pharmacologically active tannin molecules, and further studies are therefore necessary to determine the toxicity of the plant and ensure its safe use for animal and human health. Key words: Psidium guineense, tannins, isolation, antibacterial activity, Staphylococcus aureus, Pseudomonas aeruginosa.

Glucose esters as biobased PVC plasticizers

Utilization of glucose, produced by liquefaction of cellulose or other abundant biomass sources, as raw material for production of green plasticizers would offer an attractive alternative to traditional phthalate plasticizers. Three glucose hexanoate esters (GHs) were synthesized by one-step reaction and evaluated as green plasticizers for poly(vinyl chloride) (PVC). The esterification was carried out for three different time periods to obtain plasticizers with different number of hexanoate groups, as the degree of substitution could influence the miscibility between PVC and GHs. A fast and powerful laser desorption ionization-mass spectrometry (LDI-MS) method was developed to obtain molecular level structural information of the plasticizer structures. All the GHs showed good miscibility with PVC and the GH blends exhibited better mechanical properties, in the form of higher strain at break and lower modulus, as compared to glucose pentaacetate (GPA) and sucrose octaacetate (SOA) blends that were studied in comparison. Altogether the results indicate that the synthesized glucose esters have large potential as green PVC plasticizers and they could be a promising option to overcome the environmental problems caused by phthalate plasticizers.

Monoacryloyl esters of carbohydrates: Synthesis, polymerization and application in ceramic technology

The article presents the interdisciplinary research among organic synthesis, chemistry of polymers and ceramic technology. It presents the synthesis of monoacryloyl esters of fructose and glucose that is 1-O-acryloyl-d-fructose and 3-O-acryloyl-d-glucose, conditions of their polymerization and application in shaping of advanced ceramic powders by the so called gelcasting method. The paper presents the influence of carbohydrate esters on the viscosity of Al2O3 suspensions and microstructure of final ceramic samples. The results showed that synthesized esters of saccharides can play the role of organic monomers able to polymerize in situ and self-cross-linking compounds in gelcasting. The paper presents the proposed structure of polymeric network which is formed from acryloyl ester of glucose during gelcasting process. The paper describes rheological behaviour of slurries composed of synthesized substances and A2O3 powders, wetting angles of alumina substrate by synthesized compounds, differences in glass transition temperatures of polymers and the microstructure of obtained final ceramic samples.

Role of two UDP-Glycosyltransferases from the L group of arabidopsis in resistance against pseudomonas syringae

The role of the salicylic acid (SA) glycosides SA 2-O-β-D-glucose (SAG), SA glucose ester (SGE) and the glycosyl transferases UGT74F1 and UGT74F2 in the establishment of basal resistance of Arabidopsis against Pseudomonas syringae pv tomato DC3000 (Pst) was investigated. Both mutants altered in the corresponding glycosyl transferases (ugt74f1 and ugt74f2) were affected in their basal resistance against Pst. The mutant ugt74f1 showed enhanced susceptibility, while ugt74f2 showed enhanced resistance against the same pathogen. Both mutants have to some extent, altered levels of SAG and SGE compared to wild type plants, however, in response to the infection, ugt74f2 accumulated higher levels of free SA until 24 hpi compared to wild type plants while ugt74f1 accumulated lower SA levels. These SA levels correlated well with reduced expression in PR1 and EDS1 in ugt74f1. In contrast, ugt74f2 has enhanced expression of Enhanced Disease Susceptibility 1 (EDS1) but a strong reduction in the expression of several jasmonate (JA)-dependent genes. Bacterial infection interfered with the expression of Fatty Acid Desaturase (FAD), Lipoxygenase2 (LOX2), carboxyl methyltransferase1 (BSMT1) and 9-cis-epoxycarotenoid dioxygenase (NCED3) genes in ugt74f1, thus promoting an antagonistic effect with SA-signalling and leading to enhanced bacterial growth. UGT74F2 might be a target for bacterial effectors since bacterial mutants affected in effector synthesis were impaired in inducing UGT74F2 expression. These results suggest that UGT74F2 negatively influences the accumulation of free SA, hence leading to an increased susceptibility due to reduced SA levels and increased expression of the JA and ABA markers LOX-2, FAD and NCED-3.

The protective role of ellagitannins flavonoids pretreatment against N-nitrosodiethylamine induced-hepatocellular carcinoma

Ellagitannins are esters of glucose with hexahydroxydiphenic acid; when hydrolyzed, they yield ellagic acid (EA), the dilactone of hexahydroxydiphenic acid. EA has been receiving the most attention, because it has potent antioxidant activity, radical scavenging capacity, chemopreventive and antiapoptotic properties. Hepatocellular carcinoma (HCC) is the most frequent primary malignancy of liver, and accounts for as many as one million deaths worldwide in a year. The aim of the present study was to evaluate the antioxidant and chemopreventive efficiency of ellagic acid against N-nitrosodiethylamine (NDEA) induced hepatocarcinogenesis in rats. Rats were classified into four groups as follows: normal control group, group injected i.p. with a single dose (200mg/kgb.wt.) of NDEA, third group daily administered orally EA with a dose of 50mg/kgb.wt. for 7days before and 14days after NDEA administration, and fourth group received a similar dose of EA for 21days after the dose of NDEA administration. The model of NDEA-injected hepatocellular carcinomic (HCC) rats elicited significant declines in liver antioxidant enzyme activities; glutathione peroxidase (GPX), gamma glutamyl transferase (γ-GT) and glutathione-S-transferase (GST), with a reduction in reduced glutathione (GSH) and serum total protein with concomitant significant elevations in tumor markers arginase and α-l-fucosidase, and liver enzymes; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PD), direct and total bilirubin. The oral administration of EA as a protective agent, produced significant increases in tested antioxidant enzyme activities and serum total protein concomitant with significant decreases in the levels of tumor markers arginase and α-l-fucosidase as well as liver enzymes, direct and total bilirubin. Similarly, the oral administration of EA, as a curative agent produced similar changes to those when EA was used as a protective agent, but to a lesser extent. In addition, it was noted that HCC rats exhibited a degree of DNA fragmentation; however, EA administration partially inhibited the DNA fragmentation. Therefore, EA has the ability to scavenge free radicals, prevent DNA fragmentation, reduce liver injury and protect against oxidative stress.

Two-step process for preparation of oligosaccharide propionates and acrylates using lipase and Cyclodextrin Glycosyl Transferase (CGTase)

Abstract Background Oligosaccharide esters are attractive candidates for applications as surfactants, hydrogels and other materials, but direct enzymatic acylation is difficult with carbohydrates longer than disaccharides. Results A combination of one lipase-catalyzed step and one transglycosylation step catalyzed by a cyclodextrin glycosyl transferase (CGTase) was used to synthesize oligosaccharide esters. The conversion of glucose and maltose with vinyl propionate catalyzed by Candida antarctica lipase B (Novozym 435) in dioxane proceeded to full conversion to mixtures of mono and diesters. When ethyl acrylate was used as acyl donor, mono and diesters were formed, but full conversion was not reached. The CGTase catalyzed reactions between the glucose and maltose esters and α-cyclodextrin were carried out in water. In the initial phase, addition of the glucose residues of the cyclodextrin to the ester substrate occurred (coupling reaction), followed by disproportionation reactions yielding a range of oligosaccharide esters with varying chain length. The monoesters were efficient acceptors in the CGTase-catalyzed reactions, while the diesters were not converted to a significant extent. As a consequence, the glucose propionate which contained large amounts of diesters was converted to 40% conversion while the maltose propionate which contained mainly monoesters was converted to 86% conversion. Conclusions A two-step enzymatic process for preparation of oligosaccharide esters has been developed. Oligosaccharide propionates were produced in high yield with a total reaction time of 5 h. The double bond of the acrylate moiety reduced the reaction rate of the lipase catalyzed transesterification, but in both cases, the CGTase efficiently converted the monoesters to oligosaccharide esters.

Effect of the Extraction Technique and Operational Conditions on the Recovery of Bioactive Compounds from Chestnut (Castanea sativa) Bur and Shell

The aim of this work was to study the extraction of phenolic compounds from chestnut bur and shell, both waste products of chestnut processing in the food industry. Two extraction techniques were compared—maceration with solvents and microwave-assisted extraction. The influence of the solvent used (water, 50% MeOH or 50% EtOH) and temperature (25-50-75°C) on extraction yield and extract total phenols content and FRAP, DPPH, and ABTS antioxidant activities was studied. In the conventional extraction, the yield was significantly higher for the bur (8.54–19.58%) than for the shell (2.91–13.27%); however, the shell extracts showed substantially greater properties. The best extract properties were achieved at 75°C using 50% MeOH for the bur and water for the shell and phenolic compounds with demonstrated antioxidant properties, as gallic acid esters of glucose and ellagic acid, were identified in these extracts by RP-HPLC-ESI-TOF. In addition, the aqueous extracts showed ability to inhibit the growth of gram positive and negative bacteria but not fungi. The kinetic of the extraction process was well fitted by the Peleg's model. The non-conventional microwave-assisted extraction slightly improved the chestnut bur extraction by reducing the extraction time.

Phosphorylation of Akt Mediates Anti-Inflammatory Activity of 1-p-Coumaroyl β-D-Glucoside Against Lipopolysaccharide-Induced Inflammation in RAW264.7 Cells

Hydroxycinnamic acids have been reported to possess numerous pharmacological activities such as antioxidant, anti-inflammatory, and anti-tumor properties. However, the biological activity of 1-p-coumaroyl β-D-glucoside (CG), a glucose ester derivative of p-coumaric acid, has not been clearly examined. The objective of this study is to elucidate the anti-inflammatory action of CG in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. In the present study, CG significantly suppressed LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE2 and the protein expression of iNOS and COX-2. CG also inhibited LPS-induced secretion of pro-inflammatory cytokines, IL-1β and TNF-α. In addition, CG significantly suppressed LPS-induced degradation of IκB. To elucidate the underlying mechanism by which CG exerts its anti-inflammatory action, involvement of various signaling pathways were examined. CG exhibited significantly increased Akt phosphorylation in a concentration-dependent manner, although MAPKs such as Erk, JNK, and p38 appeared not to be involved. Furthermore, inhibition of Akt/PI3K signaling pathway with wortmannin significantly, albeit not completely, abolished CG-induced Akt phosphorylation and anti-inflammatory actions. Taken together, the present study demonstrates that Akt signaling pathway might play a major role in CG-mediated anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells.

Ellagitannin oligomers and a neolignan from pomegranate arils and their inhibitory effects on the formation of advanced glycation end products

Two new ellagitannin oligomers, pomegraniins A (7, tetramer) and B (8, pentamer), and a new glucose ester of neolignan, pomegralignan (19), together with six known ellagitannins, were isolated from the arils and pericarps of Punica granatum L. (pomegranate). The structures of the new compounds were elucidated based on spectroscopic analyses and chemical evidence. The known ellagitannins included oligomers such as oenothein B (4), eucalbanin B (5), and eucarpanin T1 (6), in addition to the known ellagitannin monomers such as punicalagin (1), punicalin (2), and punicacortein C (3). This paper therefore represents the first report concerning the isolation of ellagitannin oligomers from pomegranate. Examination of the inhibitory activities of the polyphenolic constituents from pomegranate towards the formation of advanced glycation end products (AGEs) revealed that all ellagitannins tested were more potent inhibitors than aminoguanidine, which was used as a positive control, and pomegraniin A (7) showed the most potent effect.

Comparative structural profiling of trichome specialized metabolites in tomato (Solanumlycopersicum) and S. habrochaites: acylsugar profiles revealed by UHPLC/MS and NMR.

Many plants accumulate large quantities of specialized metabolites in secretory glandular trichomes (SGTs), which are specialized epidermal cells. In the genus Solanum, SGTs store a diverse collection of glucose and sucrose esters. Profiling of extracts from two accessions (LA1777 and LA1392) of Solanum habrochaites using ultra-high performance liquid chromatography–mass spectrometry (UHPLC/MS) revealed wide acylsugar diversity, with up to 11 isomers annotated for each individual elemental formula. These isomers arise from differences in ester chain lengths and their positions of substitution or branching. Since fragment ion masses were not sufficient to distinguish all isomers, 24 acylsucroses were purified from S. habrochaites accessions and cultivated tomato (Solanum lycopersicum M82) and characterized using NMR spectroscopy. Two-dimensional NMR spectra yielded assignments of positions of substitution of specific acyl groups, and locations of branching. The range of substitution was wider than reported earlier, and in contrast to previous reports, tetra- and penta-acylsucroses were substituted at position 2 with acyl groups other than acetate. Because UHPLC/MS fails to yield sufficient information about structure diversity, and quantitative NMR of acylsugar mixtures is confounded by structural redundancy, the strategic combination of NMR and UHPLC/MS provides a powerful approach for profiling a class of metabolites with great structural diversity across genotypes.Electronic supplementary materialThe online version of this article (doi:10.1007/s11306-013-0585-y) contains supplementary material, which is available to authorized users.

Increase in Cytokinin Levels during Ripening in DevelopingVitis viniferacv. Shiraz Berries

We describe the quantification of the phytohormone abscisic acid and its metabolites and a range of cytokinins and gibberellic acid species in the same grape (<i>Vitis vinifera</i> L.) berry pericarp developmental series. Some relatively minor differences in concentrations were observed for some abscisic acid metabolites and gibberellic acids when compared to previous studies. The biologically active gibberellic acids 4 and 7 (along with precursor and inactive forms) were present before veraison but at very low concentrations after veraison. Abscisic acid levels peaked shortly after veraison, but high levels of dihydrophaseic acid before veraison and high levels of abscisic acid glucose ester after veraison suggest that two different catabolic pathways are developmentally controlled. The analysis of the concentrations of certain cytokinins provided some previously unreported and surprising results, as the concentration of isopentenyladenine increased rapidly at veraison and remained at elevated levels throughout ripening. The reason for this phenomenon is unknown, but a similar increase in the concentrations of some cytokinins has been observed during kiwifruit development and may be involved in the control of ripening and/or senescence.

The role of FaBG3 in fruit ripening and B. cinerea fungal infection of strawberry

In plants, β-glucosidases (BG) have been implicated in developmental and pathogen defense, and are thought to take part in abscisic acid (ABA) synthesis via hydrolysis of ABA glucose ester to release active ABA; however, there is no genetic evidence for the role of BG genes in ripening and biotic/abiotic stress in fruits. To clarify the role of BG genes in fruit, eight Fa/FvBG genes encoding β-glucosidase were isolated using information from the GenBank strawberry nucleotide database. Of the Fa/FvBG genes examined, expression of FaBG3 was the highest, showing peaks at the mature stage, coincident with the changes observed in ABA content. To verify the role of this gene, we suppressed the expression of FaBG3 via inoculation with Agrobacterium tumefaciens containing tobacco rattle virus carrying a FaBG3 fragment (RNAi). The expression of FaBG3 in FaBG3-RNAi-treated fruit was markedly reduced, and the ABA content was lower than that of the control. FaBG3-RNAi-treated fruit did not exhibit full ripening, and were firmer, had lower sugar content, and were pale compared with the control due to down-regulation of ripening-related genes. FaBG3-RNAi-treated fruit with reduced ABA levels were much more resistant to Botrytis cinerea fungus but were more sensitive to dehydration stress than control fruit. These results indicate that FaBG3 may play key roles in fruit ripening, dehydration stress and B.cinerea fungal infection in strawberries via modulation of ABA homeostasis and transcriptional regulation of ripening-related genes.

Impact of Irrigation Strategies on Abscisic Acid and its Catabolites Profiles in Leaves and Berries of Baco noir Grapes

To understand the relationship among soil and plant water status, plant physiology, and the hormonal profiles associated with it, abscisic acid (ABA) and its catabolites [phaseic acid (PA), dihydrophaseic acid (DPA), 7-hydroxy-ABA, 8′-hydroxy-ABA, neophaseic acid, and abscisic acid glucose ester (ABA-GE)] in leaves and berries from wine grape cultivar Baco noir (Folle blanche × Vitis riparia) were analyzed. The experiment was conducted during the growing seasons 2006 and 2007 in an irrigation trial set up in a commercial vineyard located in Niagara-on-the-Lake, ON, Canada. ABA and its metabolites were quantified using liquid chromatography with ion trap combined with electrospray ionization-mass spectrometry. The hormonal profile indicated a direct relationship between the amount of ABA and climatic factors. The ABA varied between 582 and 4,026 ng g−1 dry matter (DM), DPA between 417 and 562 ng g−1, and ABA-GE between 337 and 2,764 ng g−1 DM. At many sampling times PA in the leaves was undetectable, and its highest concentration (260 ng g−1 DM) was at beginning of July 2007. ABA followed different catabolic pathways depending on the plant water status. ABA was likely catabolized by conjugation to form ABA-GE in treatments at higher water deficit levels, whereas in treatments with high water status, the oxidation pathway leading to DPA or PA was likely preferred. The ABA and ABA-GE concentrations in the berries at harvest showed high correlation with soil and plant water status.

Enzymatic and structural characterization of hydrolysis of gibberellin A4 glucosyl ester by a rice β-d-glucosidase

In order to identify a rice gibberellin ester β-d-glucosidase, gibberellin A4 β-d-glucosyl ester (GA4-GE) was synthesized and used to screen rice β-glucosidases. Os3BGlu6 was found to have the highest hydrolysis activity to GA4-GE among five recombinantly expressed rice glycoside hydrolase family GH1 enzymes from different phylogenic clusters. The kinetic parameters of Os3BGlu6 and its mutants E178Q, E178A, E394D, E394Q and M251N for hydrolysis of p-nitrophenyl β-d-glucopyranoside (pNPGlc) and GA4-GE confirmed the roles of the catalytic acid/base and nucleophile for hydrolysis of both substrates and suggested M251 contributes to binding hydrophobic aglycones. The activities of the Os3BGlu6 E178Q and E178A acid/base mutants were rescued by azide, which they transglucosylate to produce β-d-glucopyranosyl azide, in a pH-dependent manner, while acetate also rescued Os3BGlu6 E178A at low pH. High concentrations of sodium azide (200–400mM) inhibited Os3BGlu6 E178Q but not Os3BGlu6 E178A. The structures of Os3BGlu6 E178Q crystallized with either GA4-GE or pNPGlc had a native α-d-glucosyl moiety covalently linked to the catalytic nucleophile, E394, which showed the hydrogen bonding to the 2-hydroxyl in the covalent intermediate. These data suggest that a GH1 β-glucosidase uses the same retaining catalytic mechanism to hydrolyze 1-O-acyl glucose ester and glucoside.

UGT74D1 Is a Novel Auxin Glycosyltransferase from Arabidopsis thaliana

Auxin is one type of phytohormones that plays important roles in nearly all aspects of plant growth and developmental processes. The glycosylation of auxins is considered to be an essential mechanism to control the level of active auxins. Thus, the identification of auxin glycosyltransferases is of great significance for further understanding the auxin regulation. In this study, we biochemically screened the group L of Arabidopsis thaliana glycosyltransferase superfamily for enzymatic activity toward auxins. UGT74D1 was identified to be a novel auxin glycosyltransferase. Through HPLC and LC-MS analysis of reaction products in vitro by testing eight substrates including auxins and other compounds, we found that UGT74D1 had a strong glucosylating activity toward indole-3-butyric acid [IBA], indole-3-propionic acid [IPA], indole-3-acetic acid [IAA] and naphthaleneacetic acid [NAA], catalyzing them to form corresponding glucose esters. Biochemical characterization showed that this enzyme had a maximum activity in HEPES buffer at pH 6.0 and 37°C. In addition, the enzymatic activity analysis of crude protein and the IBA metabolite analysis from transgenic Arabidopsis plants overexpressing UGT74D1 gene were also carried out. Experimental results indicated that over-production of the UGT74D1 in plants indeed led to increased level of the glucose conjugate of IBA. Moreover, UGT74D1 overexpression lines displayed curling leaf phenotype, suggesting a physiological role of UGT74D1 in affecting the activity of auxins. Our current data provide a new target gene for further genetic studies to understand the auxin regulation by glycosylation in plants.

Abstract 194: Delay in the progression of lung adenoma to adenocarcinoma in mice by oral consumption of pomegranate fruit extract.

Abstract Lung cancer has the highest United States and worldwide rate of cancer mortality, exceeding the mortality rates of colorectal, breast and prostate cancers combined. Tobacco smoking is well established as the major etiological risk factor for lung cancer, contributing to an increased risk in long-term smokers compared with non-smokers. The risk of the development of lung cancer in lifelong smokers is 20-40 times higher than that in non-smokers. Moreover, tobacco use accounts for 30% of overall lung cancer mortality. Given the large population at increased risk of developing lung cancer, the development of approaches to prevent smoking related lung cancer would have great clinical benefit. Pomegranate (Punica granatum, Punicaceae), is an edible fruit cultivated in Mediterranean countries, Afghanistan, India, China, Japan, Russia and the United States. Based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, pomegranate fruit extract (PFE) was found to contain anthocyanins (such as delphinidin, cyanidin and pelargonidin) and several hydrolyzable tannins (such as punicalin, pedunculagin, punicalagin, gallagic and ellagic acid esters of glucose) which account for 92% of the antioxidant activity of the whole fruit. We have earlier reported that PFE inhibits prosurvival signaling pathways in human lung carcinoma A549 cells and tumor growth in athymic nude mice (Carcinogenesis 2007; 28:163-73) and A/J mice (Cancer Res 2007; 67:3475-82). In this study, the effect of PFE consumption during progression of lung adenomas to adenocarcinomas was investigated in two mouse tumor protocols. NNK, a tobacco-specific N-nitrosamine, is believed to be one of the most promising candidates of lung carcinogen in humans. B(a)P is one of the most ubiquitous environmental polycyclic aromatic hydrocarbons present in automobile exhaust and cigarette smoke and it induces lung tumors in mice. Since majority of current and ex-smokers have small nodules, it is highly desirable to prevent additional growth of lung cancer after the appearance of nodules. To mimic this situation, PFE (0.2% PFE, w/v) was given to A/J mice in drinking water after the establishment of lung adenomas induced by NNK and B(a)P. Treatment with PFE significantly reduced the lung tumor multiplicity by 33% in mice treated with NNK and 29% in B(a)P-treated mice. PFE also caused significant reduction in the expression of COX-2, RAR-β, VEGF, CD-31 and angiopoietin-2 in lungs of mice treated with NNK and B(a)P. On administration of PFE, there was decrease in the multiplicity and incidence of lung adenomas and adenocarcinomas in mice treated with NNK and B(a)P. Thus, our results indicate that PFE has the potential to be developed as an agent against tobacco smoke-induced lung cancer and for improving the quality of life of early stage lung cancer patients and ex-smokers. Citation Format: Naghma Khan, Ruth Sullivan, Tien Hoang, Tejaswi Dittakavi, Hasan Mukhtar. Delay in the progression of lung adenoma to adenocarcinoma in mice by oral consumption of pomegranate fruit extract. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 194. doi:10.1158/1538-7445.AM2013-194

Rice Os9BGlu31 Is a Transglucosidase with the Capacity to Equilibrate Phenylpropanoid, Flavonoid, and Phytohormone Glycoconjugates

Glycosylation is an important mechanism of controlling the reactivities and bioactivities of plant secondary metabolites and phytohormones. Rice (Oryza sativa) Os9BGlu31 is a glycoside hydrolase family GH1 transglycosidase that acts to transfer glucose between phenolic acids, phytohormones, and flavonoids. The highest activity was observed with the donors feruloyl-glucose, 4-coumaroyl-glucose, and sinapoyl-glucose, which are known to serve as donors in acyl and glucosyl transfer reactions in the vacuole, where Os9BGlu31 is localized. The free acids of these compounds also served as the best acceptors, suggesting that Os9BGlu31 may equilibrate the levels of phenolic acids and carboxylated phytohormones and their glucoconjugates. The Os9BGlu31 gene is most highly expressed in senescing flag leaf and developing seed and is induced in rice seedlings in response to drought stress and treatment with phytohormones, including abscisic acid, ethephon, methyljasmonate, 2,4-dichlorophenoxyacetic acid, and kinetin. Although site-directed mutagenesis of Os9BGlu31 indicated a function for the putative catalytic acid/base (Glu(169)), catalytic nucleophile residues (Glu(387)), and His(386), the wild type enzyme displays an unusual lack of inhibition by mechanism-based inhibitors of GH1 β-glucosidases that utilize a double displacement retaining mechanism.

ChemInform Abstract: Reinvestigation of Structures of Robustasides B (Ia) and C (Ib), and Isolation of (E)‐2,5‐Dihydroxycinnamic Acid Esters of Arbutin (Ic) and Glucose (II) from the Leaves of Grevillea robusta.

ChemInform Abstract: Reinvestigation of Structures of Robustasides B (Ia) and C (Ib), and Isolation of (E)‐2,5‐Dihydroxycinnamic Acid Esters of Arbutin (Ic) and Glucose (II) from the Leaves of Grevillea robusta.

Lipase‐catalyzed synthesis of secondary glucose esters under continuous flow conditions

AbstractChemical methods for the synthesis of sugar esters require the use of high temperatures in the presence of alkaline catalysts resulting in undesirable by‐products and low regiosselectivity. Sugar‐based fatty acid esters are non‐ionic, biodegradable, odorless, non‐irritating, non‐toxic surfactants widely used pharmaceuticals, cosmetics, detergents, and food industry. Here in we report our results on enzymatic esterification of protected glucose (glucose ketal) with several fatty acids using the immobilized lipase from Rhizomucor miehei under batch and continuous flow conditions, to afford new glucose derivatives with potential surfactant properties. The results presented here shows that high conversions can be obtained in short reaction time.Practical application: The research of new non‐toxic, environmentally friendly and biodegradable surfactants to replace chemicals has increased along with the development of green chemistry. Nonionic biosurfactants, such as sugar fatty acid esters, may be obtained by enzymatic synthesis, a simple manufacturing method for application in several areas, including food, cosmetic, detergent, and pharmaceutical industry. In this work we have described the uncommon esterification of a steric hindered secondary hydroxyl group on glucose ketal leading to new glucose derivatives with potential application as surfactants.