Active Hexose-Correlated Compound Shows Direct and Indirect Effects against Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a disease characterized by the accumulation of mature CD19+CD5+CD23+ B cells in the bloodstream and in lymphoid organs. It usually affects people over 70 years of age, which limits the options for treatments. The disease is typically well-managed, but to date is still incurable. Hence, the need for novel therapeutic strategies remains. Nurse-like cells (NLCs) are major components of the microenvironment for CLL, supporting tumor cell survival, proliferation, and even drug resistance. They are of myeloid lineage, guided toward differentiating into their tumor-supportive role by the CLL cells themselves. As such, they are analogous to tumor-associated macrophages and represent a major therapeutic target. Previously, it was found that a mushroom extract, Active Hexose-Correlated Compound (AHCC), promoted the death of acute myeloid leukemia cells while preserving normal monocytes. Given these findings, it was asked whether AHCC might have a similar effect on the abnormally differentiated myeloid-lineage NLCs in CLL. CLL-patient PBMCs were treated with AHCC, and it was found that AHCC treatment showed a direct toxic effect against isolated CLL cells. In addition, it significantly reduced the number of tumor-supportive NLCs and altered their phenotype. The effects of AHCC were then tested in the Eµ-TCL1 mouse model of CLL and the MllPTD/WT Flt3ITD/WT model of AML. Results showed that AHCC not only reduced tumor load and increased survival in the CLL and AML models, but it also enhanced antitumor antibody treatment in the CLL model. These results suggest that AHCC has direct and indirect effects against CLL and that it may be of benefit when combined with existing treatments.

Genotoxicity assessment of 1,4-anhydro-4-seleno-D-talitol (SeTal) in human liver HepG2 and HepaRG cells

1,4-Anhydro-4-seleno-D-talitol (SeTal) is a highly water-soluble selenosugar with interesting antioxidant and skin-tissue-repair properties; it is highly stable in simulated gastric and gastrointestinal fluids and is a potential pharmaceutical ingredient that may be administered orally. Hepatic toxicity is often a major problem with novel drugs and can result in drug withdrawal from the market. Predicting hepatotoxicity is therefore essential to minimize late failure in the drug-discovery process. Herein, we report in vitro studies to evaluate the cytotoxic and genotoxic potential of SeTal in HepG2 and hepatocyte-like differentiated HepaRG cells. Except for extremely high concentrations (10 mM, 68 h-treatment in HepG2), SeTal did not affect the viability of each cell type. While the highest examined concentrations (0.75 and 1 mM in HepG2; 1 mM in HepaRG) were observed to induce primary DNA damage, SeTal did not exhibit clastogenic or aneugenic activity toward either HepG2 or HepaRG cells. Moreover, no significant cytostasis variations were observed in any experiment. The clearly negative results observed in the CBMN test suggest that SeTal might be used as a potential active pharmaceutical ingredient. The present study will be useful for the selection of non-toxic concentrations of SeTal in future investigations.

A gulose moiety contributes to the belomycin (BLM) disaccharide selective targeting to lung cancer cells

Eight mono- or disaccharide analogues derived from BLM disaccharide, along with the corresponding carbohydate-dye conjugates have been designed and synthesized in this study, aiming at exploring the effect of a gulose residue on the cellular binding/uptake of BLM disaccharide and it possible uptake mechanism. Our evidence is presented indicating that, for the cellular binding/uptake of BLM disaccharide, a gulose residue is an essential subunit but unrelated to its chemical nature. Interestingly, d-gulose-dye conjugate is able to selectively target A549 cancer cells, but l-gulose-dye conjugate fails. Further uptake mechanism studies demonstrate d-gulose-dye derivatives similar to BLM disaccharide-dye ones behave in a temperature- and ATP-dependent manner, and are partly directed by the GLUT1 receptor. Moreover, d-gulose modifying gemcitabine 53a exhibits more potent antitumor activity compared to derivatives 53b-c in which gemcitabine is decorated with other monosaccharides. Taken together, the monosacharide d-gulose conjugate offers a new strategy for solving cytotoxic drugs via the increased tumor targeting in the therapy of lung cancer.

Surface-functionalized curcumin-loaded polymeric nanocapsules could block apomorphine-induced behavioral changes in rats

BACKGROUND

Surface functionalization enhances the properties and characteristics of polymeric nanocapsules (NCs) mainly due to the surface charge, surfactants, and polymer coating type. Curcumin (CUR) is a bioactive compound with several proven pharmacological properties and low bioavailability. This study aimed to develop anionic (poly-ɛ-caprolactone; PCL) and cationic (Eudragit^® RS100 (EUD)) NCs prepared with sorbitan monostearate (Span 60^®) or sorbitan monooleate (Span 80^®), coated with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and optimized using 2³ factorial analysis. Subsequently, the biological activity was evaluated.

METHODS

A two-level, three-factor design (polymer, Span type, and TPGS concentration) was used. The biological effects of CUR-loaded TPGS-coated cationic and anionic NCs were assessed in apomorphine-induced stereotyped behavior in rats.

RESULTS

The type of polymer (anionic or cationic) and Span^® had a factorial influence on the physical and chemical characteristics of NCs according to the changes in TPGS concentrations. Both cationic and anionic CUR-NCs could block apomorphine-induced behavioral changes.

CONCLUSIONS

The CUR-loaded TPGS-coated NCs proved to be a promising brain delivery system.

Evaluation of Antimicrobial Effect of Air-Polishing Treatments and Their Influence on Human Dental Pulp Stem Cells Seeded on Titanium Disks

Dental implants are one of the most frequently used treatment options for tooth replacement, and titanium is the metal of choice due to its demonstrated superiority in resisting corrosion, lack of allergic reactions and mechanical strength. Surface roughness of titanium implants favors the osseointegration process; nevertheless, its topography may provide a suitable substrate for bacterial biofilm deposition, causing peri-implantitis and leading to implant failure. Subgingival prophylaxis treatments with cleansing powders aimed to remove the bacterial accumulation are under investigation. Two different air-polishing powders—glycine and tagatose—were assayed for their cleaning and antimicrobial potential against a Pseudomonas biofilm and for their effects on human dental pulp stem cells (hDPSCs), seeded on sandblasted titanium disks. Immunofluorescence analyses were carried out to evaluate cell adhesion, proliferation, stemness and osteogenic differentiation. The results demonstrate that both the powders have a great in vitro cleaning potential in the early period and do not show any negative effects during hDPSCs osteogenic differentiation process, suggesting their suitability for enhancing the biocompatibility of titanium implants. Our data suggest that the evaluated cleansing systems reduce microbial contamination and allow us to propose tagatose as an adequate alternative to the gold standard glycine for the air-polishing prophylaxis treatment.

Molecular process of glucose uptake and glycogen storage due to hamamelitannin via insulin signalling cascade in glucose metabolism

Understanding the mechanism by which the exogenous biomolecule modulates the GLUT-4 signalling cascade along with the information on glucose metabolism is essential for finding solutions to increasing cases of diabetes and metabolic disease. This study aimed at investigating the effect of hamamelitannin on glycogen synthesis in an insulin resistance model using L6 myotubes. Glucose uptake was determined using 2-deoxy-D-[1-³H] glucose and glycogen synthesis were also estimated in L6 myotubes. The expression levels of key genes and proteins involved in the insulin-signaling pathway were determined using real-time PCR and western blot techniques. The cells treated with various concentrations of hamamelitannin (20 µM to 100 µM) for 24 h showed that, the exposure of hamamelitannin was not cytotoxic to L6 myotubes. Further the 2-deoxy-D-[1-³H] glucose uptake assay was carried out in the presence of wortmannin and Genistein inhibitor for studying the GLUT-4 dependent cell surface recruitment. Hamamelitannin exhibited anti-diabetic activity by displaying a significant increase in glucose uptake (125.1%) and glycogen storage (8.7 mM) in a dose-dependent manner. The optimum concentration evincing maximum activity was found to be 100 µm. In addition, the expression of key genes and proteins involved in the insulin signaling pathway was studied to be upregulated by hamamelitannin treatment. Western blot analysis confirmed the translocation of GLUT-4 protein from an intracellular pool to the plasma membrane. Therefore, it can be conceived that hamamelitannin exhibited an insulinomimetic effect by enhancing the glucose uptake and its further conversion into glycogen by regulating glucose metabolism.

The rare sugar D-tagatose protects plants from downy mildews and is a safe fungicidal agrochemical

The rare sugar D-tagatose is a safe natural product used as a commercial food ingredient. Here, we show that D-tagatose controls a wide range of plant diseases and focus on downy mildews to analyze its mode of action. It likely acts directly on the pathogen, rather than as a plant defense activator. Synthesis of mannan and related products of D-mannose metabolism are essential for development of fungi and oomycetes; D-tagatose inhibits the first step of mannose metabolism, the phosphorylation of D-fructose to D-fructose 6-phosphate by fructokinase, and also produces D-tagatose 6-phosphate. D-Tagatose 6-phosphate sequentially inhibits phosphomannose isomerase, causing a reduction in D-glucose 6-phosphate and D-fructose 6-phosphate, common substrates for glycolysis, and in D-mannose 6-phosphate, needed to synthesize mannan and related products. These chain-inhibitory effects on metabolic steps are significant enough to block initial infection and structural development needed for reproduction such as conidiophore and conidiospore formation of downy mildew.

Comparative Study of Aryl O-, C-, and S-Mannopyranosides as Potential Adhesion Inhibitors toward Uropathogenic E. coli FimH

A set of three mannopyranoside possessing identical 1,1'-biphenyl glycosidic pharmacophore but different aglyconic atoms were synthesized using either a palladium-catalyzed Heck cross coupling reaction or a metathesis reaction between their corresponding allylic glycoside derivatives. Their X-ray structures, together with their calculated 3D structures, showed strong indicators to explain the observed relative binding abilities against E. coli FimH as measured by a improved surface plasmon resonance (SPR) method. Amongst the O-, C-, and S-linked analogs, the C-linked analog showed the best ability to become a lead candidate as antagonist against uropathogenic E. coli with a Kd of 11.45 nM.

Calorie Restriction Mimetics: Upstream-Type Compounds for Modulating Glucose Metabolism

Calorie restriction (CR) can prolong the human lifespan, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition, while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-d-glucose, d-glucosamine, and d-allulose, which show antiaging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.

N-Glycoproteomic Characterization of Mannosidase and Xylosyltransferase Mutant Strains of Chlamydomonasreinhardtii

At present, only little is known about the enzymatic machinery required for N-glycosylation in Chlamydomonas reinhardtii, leading to the formation of N-glycans harboring Xyl and methylated Man. This machinery possesses new enzymatic features, as C. reinhardtii N-glycans are independent of β1,2-N-acetylglucosaminyltransferase I. Here we have performed comparative N-glycoproteomic analyses of insertional mutants of mannosidase 1A (IM Man1A ) and xylosyltransferase 1A (IM XylT1A ). The disruption of man1A affected methylation of Man and the addition of terminal Xyl. The absence of XylT1A led to shorter N-glycans compared to the wild type. The use of a IM Man1A xIM XylT1A double mutant revealed that the absence of Man1A suppressed the IM XylT1A phenotype, indicating that the increased N-glycan trimming is regulated by core β1,2-Xyl and is dependent on Man1A activity. These data point toward an enzymatic cascade in the N-glycosylation pathway of C. reinhardtii with interlinked roles of Man1A and XylT1A. The results described herein represent the first step toward a functional characterization of the enzymatic N-glycosylation machinery in C. reinhardtii.

Differential Effects of Carbohydrates on Arabidopsis Pollen Germination

Pollen germination as a crucial process in plant development strongly depends on the accessibility of carbon as energy source. Carbohydrates, however, function not only as a primary energy source, but also as important signaling components. In a comprehensive study, we analyzed various aspects of the impact of 32 different sugars on in vitro germination of Arabidopsis pollen comprising about 150 variations of individual sugars and combinations. Twenty-six structurally different mono-, di- and oligosaccharides, and sugar analogs were initially tested for their ability to support pollen germination. Whereas several di- and oligosaccharides supported pollen germination, hexoses such as glucose, fructose and mannose did not support and even considerably inhibited pollen germination when added to germination-supporting medium. Complementary experiments using glucose analogs with varying functional features, the hexokinase inhibitor mannoheptulose and the glucose-insensitive hexokinase-deficient Arabidopsis mutant gin2-1 suggested that mannose- and glucose-mediated inhibition of sucrose-supported pollen germination depends partially on hexokinase signaling. The results suggest that, in addition to their role as energy source, sugars act as signaling molecules differentially regulating the complex process of pollen germination depending on their structural properties. Thus, a sugar-dependent multilayer regulation of Arabidopsis pollen germination is supported, which makes this approach a valuable experimental system for future studies addressing sugar sensing and signaling.

The commonly used nonionic surfactant Span 80 has RXRα transactivation activity, which likely increases the obesogenic potential of oil dispersants and food emulsifiers

Obesity has reached pandemic proportions, and there is mounting evidence that environmental exposures to endocrine disrupting chemicals known as "obesogens" may contribute to obesity and associated medical conditions. The Deepwater Horizon (DWH) oil spill resulted in a massive environmental release of crude oil and remediation efforts applied large quantities of Corexit dispersants to the oil spill. The Corexit-enhanced Water Accommodated Fraction (CWAF) of DWH crude oil contains PPARγ transactivation activity, which is attributed to dioctyl sodium sulfosuccinate (DOSS), a probable obesogen. In addition to its use in oil dispersants, DOSS is commonly used as a stool softener and food additive. Because PPARγ functions as a heterodimer with RXRα to transcriptionally regulate adipogenesis we investigated the potential of CWAF to transactivate RXRα and herein demonstrated that the Corexit component Span 80 has RXRα transactivation activity. Span 80 bound to RXRα in the low micromolar range and promoted adipocyte differentiation of 3T3-L1 preadipocytes. Further, the combination of DOSS and Span 80 increased 3T3-L1 adipocyte differentiation substantially more than treatment with either chemical individually, likely increasing the obesogenic potential of Corexit dispersants. From a public health standpoint, the use of DOSS and Span 80 as food additives heightens concerns regarding their use and mandates further investigations.

Optimizing Polychlorinated Biphenyl Degradation by Flavonoid-Induced Cells of the Rhizobacterium Rhodococcus erythropolis U23A

There is evidence that many plant secondary metabolites may act as signal molecules to trigger the bacterial ability to metabolize polychlorinated biphenyls (PCBs) during the rhizoremediation process. However, the bases for the PCB rhizoremediation process are still largely unknown. The rhizobacterium Rhodococcus erythropolis U23A is unable to use flavanone as a growth substrate. However, on the basis of an assay that monitors the amount of 4-chlorobenzoate produced from 4-chlorobiphenyl by cells grown co-metabolically on flavanone plus sodium acetate, this flavonoid was previously found to be a potential inducer of the U23A biphenyl catabolic pathway. In this work, and using the same assay, we identified ten other flavonoids that did not support growth, but that acted as inducers of the U23A biphenyl pathway, and we confirmed flavonoid induction of the biphenyl catabolic pathway using quantitative real-time polymerase chain reaction (RT-qPCR) on the bphA gene. We also examined the effect of the growth co-substrate on flavonoid induction. Sodium acetate was replaced by glucose, mannose, sucrose, or mannitol, which are sugars found in plant root exudates. The data showed that the level of induction of strain U23A biphenyl-degrading enzymes was significantly influenced by the nature and concentration of the flavonoid in the growth medium, as well as by the substrate used for growth. Sucrose allowed for an optimal induction response for most flavonoids. Some flavonoids, such as flavone and isoflavone, were better inducers of the biphenyl catabolic enzymes than biphenyl itself. We also found that all flavonoids tested in this work were metabolized by strain U23A during co-metabolic growth, but that the metabolite profiles, as well as the level of efficiency of degradation, differed for each flavonoid. To obtain insight into how flavonoids interact with strain U23A to promote polychlorinated biphenyl (PCB) degradation, we determined the concentration of flavanone at which optimal PCB-degrading performance of strain U23A was achieved. We showed that it corresponded to the concentration required to fully induce the biphenyl catabolic pathway of the strain. Together, our data demonstrate that optimal PCB degradation during the rhizoremediation process will require the adjustment of several parameters, including the presence of the appropriate flavonoids at the proper concentrations and the presence of proper growth substrates that positively influence the ability of flavonoids to induce the pathway.

Development and characterization of sorbitan monostearate and sesame oil-based organogels for topical delivery of antimicrobials

The current study explains the development of sorbitan monostearate and sesame oil-based organogels for topical drug delivery. The organogels were prepared by dissolving sorbitan monostearate in sesame oil (70°C). Metronidazole was used as a model antimicrobial. The formulations were characterized using phase contrast microscopy, infrared spectroscopy, viscosity, mechanical test, and differential scanning calorimetry. Phase contrast microscopy showed the presence of needle-shaped crystals in the organogel matrix. The length of the crystals increased with the increase in the sorbitan monostearate concentration. XRD studies confirmed the amorphous nature of the organogels. Viscosity study demonstrated shear thinning behavior of the organogels. The viscosity and the mechanical properties of the organogels increased linearly with the increase in the sorbitan monostearate concentration. Stress relaxation study confirmed the viscoelastic nature of the organogels. The organogels were biocompatible. Metronidazole-loaded organogels were examined for their controlled release applications. The release of the drug followed zero-order release kinetics. The drug-loaded organogels showed almost similar antimicrobial activity against Escherichia coli when compared to the commercially available Metrogyl® gel. In gist, it can be proposed that the developed organogels had sufficient properties to be used for controlled delivery of drugs.

Silencing the vacuolar invertase gene GhVIN1 blocks cotton fiber initiation from the ovule epidermis, probably by suppressing a cohort of regulatory genes via sugar signaling

Cotton fibers, the most important source of cellulose for the global textile industry, are single-celled trichomes derived from the ovule epidermis at or just prior to anthesis. Despite progress in understanding cotton fiber elongation and cell-wall biosynthesis, knowledge regarding the molecular basis of fiber cell initiation, the first step of fiber development determining the fiber yield potential, remains elusive. Here, we provide evidence that expression of a vacuolar invertase (VIN) is an early event that is essential for cotton fiber initiation. RNAi-mediated suppression of GhVIN1, a major VIN gene that is highly expressed in wild-type fiber initials, resulted in significant reduction of VIN activity and consequently a fiberless seed phenotype in a dosage dependent manner. The absence of a negative effect on seed development in these fiberless seeds indicates that the phenotype is unlikely to be due to lack of carbon nutrient. Gene expression analyses coupled with in vitro ovule culture experiments revealed that GhVIN1-derived hexose signaling may play an indispensable role in cotton fiber initiation, probably by regulating the transcription of several MYB transcription factors and auxin signaling components that were previously identified as required for fiber initiation. Together, the data represent a significant advance in understanding the mechanisms of cotton fiber initiation, and provide the first indication that VIN-mediated hexose signaling may act as an early event modulating the expression of regulatory genes and hence cell differentiation from the ovule epidermis.

Wine composition plays an important role in the control of carcinogenic precursor formation by Lactobacillus hilgardii X₁B

BACKGROUND

Lactobacillus hilgardii, a wine lactic acid bacterium, is able to use arginine, through the arginine deiminase pathway with the formation of citrulline, a precursor of the carcinogen ethyl carbamate. The influence of different Argentine wine varieties (Merlot, Cabernet Sauvignon and Malbec), on bacterial growth and arginine metabolism was examined. Furthermore, the effect of different components normally present in wines on the enzyme activities of the arginine deiminase system was determined.

RESULTS

Malbec wine under all conditions assayed (33, 50 and 100% supplemented wine:basal media) showed higher arginine consumption and citrulline production than the other wines, as well as the highest bacterial growth and survival of Lactobacillus hilgardii X₁B. Glucose and L-malic inhibited both arginine deiminase enzymes while fructose and citric acid only inhibited arginine deiminase. The red wines assayed in this study had different composition, and this is an explanation for the different behavior of the bacterium.

CONCLUSION

The highest citrulline production in Malbec wine could be correlated with its lower concentrations of glucose, fructose, citric and phenolic acid than the other wines. Therefore, a wine with lower concentration of these sugars and acids could be dangerous due to the formation of ethyl carbamate precursors.

Hamamelitannin from witch hazel (Hamamelis virginiana) displays specific cytotoxic activity against colon cancer cells

Hamamelis virginiana (witch hazel) bark is a rich source of condensed and hydrolyzable tannins reported to exert a protective action against colon cancer. The present study characterizes different witch hazel tannins as selective cytotoxic agents against colon cancer. To cover the structural diversity of the tannins that occur in H. virginiana bark, the hydrolyzable tannins, hamamelitannin and pentagalloylglucose, together with a proanthocyanidin-rich fraction (F800H4) were selected for the study. Treatment with these compounds reduced tumor viability and induced apoptosis, necrosis, and S-phase arrest in the cell cycle of HT29 cells, with hamamelitannin being the most efficient. Owing to polyphenol-mediated H(2)O(2) formation in the incubation media, the antiproliferative effect was determined in the presence and absence of catalase to rule out any such interference. The presence of catalase significantly changed the IC(50) only for F800H4. Furthermore, at concentrations that inhibit the growth of HT29 cells by 50%, hamamelitannin had no harmful effects on NCM460 normal colonocytes, whereas pentagalloylglucose inhibited both cancerous and normal cell growth. Using the TNPTM assay, we identified a highly reactive phenolic position in hamamelitannin, which may explain its efficacy at inhibiting colon cancer growth.

Effects of different sweet preloads on incretin hormone secretion, gastric emptying, and postprandial glycemia in healthy humans

BACKGROUND

Macronutrient "preloads" can stimulate glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), slow gastric emptying, and reduce postprandial glycemic excursions. After sweet preloads, these effects may be signaled by sodium-glucose cotransporter-1 (SGLT1), sweet taste receptors, or both.

OBJECTIVE

We determined the effects of 4 sweet preloads on GIP and GLP-1 release, gastric emptying, and postprandial glycemia.

DESIGN

Ten healthy subjects were studied on 4 separate occasions each. A preload drink containing 40 g glucose, 40 g tagatose/isomalt mixture (TIM), 40 g 3-O-methylglucose (3OMG; a nonmetabolized substrate of SGLT1), or 60 mg sucralose was consumed 15 min before a (13)C-octanoic acid-labeled mashed potato meal. Blood glucose, plasma total GLP-1 and GIP, serum insulin, and gastric emptying were determined.

RESULTS

Both glucose and 3OMG stimulated GLP-1 and GIP release in advance of the meal (each P < 0.05), whereas TIM and sucralose did not. The overall postprandial GLP-1 response was greater after glucose, 3OMG, and TIM than after sucralose (P < 0.05), albeit later after TIM than the other preloads. The blood glucose and insulin responses in the first 30 min after the meal were greatest after glucose (each P < 0.05). Gastric emptying was slower after both 3OMG and TIM than after sucralose (each P < 0.05).

CONCLUSIONS

In healthy humans, SGLT1 substrates stimulate GLP-1 and GIP and slow gastric emptying, regardless of whether they are metabolized, whereas the artificial sweetener sucralose does not. Poorly absorbed sweet tastants (TIM), which probably expose a greater length of gut to nutrients, result in delayed GLP-1 secretion but not in delayed GIP release. These observations have the potential to optimize the use of preloads for glycemic control. This trial was registered at www.actr.org.au as ACTRN12611000775910.

Effect of diets containing sucrose vs. D-tagatose in hypercholesterolemic mice

Effects of functional sweeteners on the development of the metabolic syndrome and atherosclerosis are unknown. The objective was to compare the effect of dietary carbohydrate in the form of sucrose (SUCR) to D-tagatose (TAG; an isomer of fructose currently used as a low-calorie sweetener) on body weight, blood cholesterol concentrations, hyperglycemia, and atherosclerosis in low-density lipoprotein receptor deficient (LDLr(-/-)) mice. LDLr(-/-) male and female mice were fed either standard murine diet or a diet enriched with TAG or SUCR as carbohydrate sources for 16 weeks. TAG and SUCR diets contained equivalent amounts (g/kg) of protein, fat, and carbohydrate. We measured food intake, body weight, adipocyte diameter, serum cholesterol and lipoprotein concentrations, and aortic atherosclerosis. Macrophage immunostaining and collagen content were examined in aortic root lesions. CONTROL and TAG-fed mice exhibited similar energy intake, body weights and blood glucose and insulin concentrations, but SUCR-fed mice exhibited increased energy intake and became obese and hyperglycemic. Adipocyte diameter increased in female SUCR-fed mice compared to TAG and CONTROL. Male and female SUCR-fed mice had increased serum cholesterol and triglyceride concentrations compared to TAG and CONTROL. Atherosclerosis was increased in SUCR-fed mice of both genders compared to TAG and CONTROL. Lesions from SUCR-fed mice exhibited pronounced macrophage immunostaining and reductions in collagen content compared to TAG and CONTROL mice. These results demonstrate that in comparison to sucrose, equivalent substitution of TAG as dietary carbohydrate does not result in the same extent of obesity, hyperglycemia, hyperlipidemia, and atherosclerosis.

In vitro anti-influenza screening of several Euphorbiaceae species: structure of a bioactive Cyanoglucoside from Codiaeum variegatum

A bio-guided screening against influenza A virus (FLUAV) was carried out with seven Euphorbiaceae species. The results showed that chromatographic fractions from Phyllantus niruri, Euphorbia pulcherrima and Codiaeum variegatum had relevant anti-FLUAV activity, although only chromatographical subfractions from C. variegatum kept the activity. From this plant, the active compound against FLUAV was isolated. Its structure was assigned as 2-(3,4,5)-trihydroxy-6-hydroxymethyltetrahydropyran-2-yloxymethyl)acrylonitrile (1) on the basis of NMR, mass spectrometry and X-ray diffraction analysis. The compound displayed virucidal activity without impairment of haemagglutination properties of the used virus strain. This is the first report indicating antiviral activity of a cyanoglucoside.

[Obtaining and study of monosaccharide derivatives of low-molecular-weight chitosan]

The possibility of obtaining monosaccharide derivatives of low-molecular-weight chitosan with the use of the Maillard reaction was studied. Chitosan derivatives (molecular weight, 24 and 5 kDa) obtained with glucosamine, N-acetyl galactosamine, galactose, and mannose with a substitution degree of 4-14% and a yield of 60-80% were obtained. Some physicochemical and biological properties of these derivatives were studied. We showed that monosaccharide derivatives of low-molecular-weight chitosan exhibited antibacterial activity. Chitosan at a concentration of 0.01% caused 100% death of bacteria B. subtilis and E. coil. The strongest antibacterial effect was exhibited by 24-kDa derivatives: only 0.02-0.08% of cells survived. These derivatives were two orders of magnitude more effective than the 5-kDa chitosan modified with galactose.

Effect of active hexose correlated compound on the production of nitric oxide in hepatocytes

BACKGROUND

Active hexose correlated compound (AHCC) is a "complex compound" containing polysaccharides. AHCC has been reported to improve the prognosis of postoperative hepatocellular carcinoma patients. However, the molecular mechanism of this improvement is not fully understood. In the diseased liver, nitric oxide (NO) generated by inducible nitric oxide synthase (iNOS) is considered to be a causal factor for various hepatopathies. In this study, the possibility of AHCC regulation of NO production by iNOS was pursued as a potential liver-protecting mechanism.

METHODS

Primary cultured rat hepatocytes were treated with interleukin-1beta (IL-1beta) in the presence or absence of AHCC. NO production, iNOS induction, and iNOS signal were analyzed.

RESULTS

IL-1beta stimulated iNOS induction through the activation of nuclear factor kappaB (NFkappaB), leading to NO production. The addition of AHCC inhibited NO production, showing >80% inhibition at 8 mg/mL. AHCC also decreased the levels of iNOS protein and mRNA. However, AHCC influenced neither the degradation of inhibitory protein kappaB (IkappaB) nor the activation of NFkappaB stimulated by IL-1beta. Transfection experiments with an iNOS promoter-luciferase construct (iNOS-Luc) revealed that AHCC had no effect on the transactivation activity of the iNOS promoter. By contrast, AHCC inhibited the activity of iNOS-Luc containing a 3'untranslated region (UTR) with adenosine and uridine (AU)-rich elements, which shows the stabilizing activity of iNOS mRNA.

CONCLUSIONS

Results indicated that AHCC inhibits the induction of iNOS at the level of transcription, causing a decrease in NO production in hepatocytes. AHCC seems to decrease the levels of iNOS mRNA by reducing mRNA stabilization rather than inhibiting its synthesis.

Regulation and function of aquaporin-1 in glioma cells

Glioblastoma multiformes (GBMs) express increased aquaporin (AQP) 1 compared to normal brain. AQPs may contribute to edema, cell motility, and shuttling of H(2)O and H(+) from intracellular to extracellular space. We sought to gain insight into AQP1 function in GBM. In cultured 9L gliosarcoma cells, AQP1 expression was induced by dexamethasone, platelet-derived growth factor, NaCl, hypoxia, D-glucose (but not L-glucose), and fructose. Induction of AQP1 expression correlated with the level of glycolysis, maximized by increasing medium D-glucose or fructose and decreasing O(2), and was quantified by measuring lactate dehydrogenase (LDH) activity and medium lactate concentration. Upregulation of the protease cathepsin B was also observed in 9L cells cultured under glycolytic conditions. Immunohistochemical staining of human GBM specimens revealed increased coincident expression of AQP1, LDH, and cathepsin B in glioma cells associated with blood vessels at the tumor periphery. GBMs are known to exhibit aerobic glycolysis. Increased glucose metabolism at the tumor periphery may provide a scenario by which upregulation of AQP1, LDH, and cathepsin B contributes to acidification of the extracellular milieu and to invasive potential of glioma cells in perivascular space. The specific upregulation and metabolic consequences of increased AQP1 in gliomas may provide a therapeutic target, both as a cell surface marker and as a functional intervention.

ATP-depleting carbohydrates prevent tumor necrosis factor receptor 1-dependent apoptotic and necrotic liver injury in mice

We demonstrated previously that depletion of hepatic ATP by endogenous metabolic shunting of phosphate after fructose treatment renders hepatocytes resistant to tumor necrosis factor (TNF)-induced apoptosis. We here address the question whether this principle extends to TNF receptor 1-mediated caspase-independent apoptotic and to necrotic liver injury. As in the apoptotic model of galactosamine/lipopolysaccharide (LPS)-induced liver damage, the necrotic hepatotoxicity initiated by sole high-dose LPS treatment was abrogated after depletion of hepatic ATP. Although systemic TNF and interferon-gamma levels were suppressed, animals still were protected when ATP depletion was initiated after the peak of proinflammatory cytokines upon LPS injection, showing that fructose-induced ATP depletion affects both cytokine release and action. In T cell-dependent necrotic hepatotoxicity elicited by concanavalin A or galactosamine + staphylococcal enterotoxin B, ATP depletion prevented liver injury as well, but here without modulating cytokine release. By attenuating caspase-8 activation, ATP depletion of hepatocytes in vitro impaired TNF receptor signaling by the death-inducing signaling complex, whereas receptor internalization and nuclear factor-kappaB activation upon TNF stimulation were unaffected. These findings demonstrate that sufficient target cell ATP levels are required for the execution of both apoptotic and necrotic TNF-receptor 1-mediated liver cell death.

Hexose-specificity of hexokinase and ADP-dependence of pyruvate kinase play important roles in the control of monosaccharide utilization in freshly diluted boar spermatozoa

Incubation of boar sperm from fresh ejaculates in a minimal medium with 10 mM glucose induced a fast and intense activation of glycolysis, as indicated by the observed increases in the intracellular levels of glucose 6-phosphate (G 6-P) and ATP and the rate of formation of extracellular L-lactate. The effect of glucose was much more intense than that induced by fructose, sorbitol, and mannose. The greater utilization of glucose was related to a much greater sensitivity to hexokinase when compared with the other monosaccharides. Thus, the presence of 0.5 mM glucose induced total hexokinase activity in supernatants from sperm extracts of 1.7 +/- 0.1 mIU/mg protein, while the same concentration of both fructose, mannose, and sorbitol induced total hexokinase activity from 0.3 +/- 0.1 mIU/mg protein to 0.60 +/- 1 mIU/mg protein. Kinetic analysis of the total pyruvate kinase activity indicated that this activity was greatly dependent on the presence of ADP and also showed a great affinity for PEP, with an estimated Km in supernatants of 0.15-0.20 mM. Immunological location of proteins closely related to glycolysis, like GLUT-3 hexose transporter and hexokinase-I, indicated that these proteins showed the trend to be distributed around or in the cellular membranes of both head and midpiece in a grouped manner. We conclude that glycolysis is regulated by both the specific availability of a concrete sugar and the internal equilibrium between ATP and ADP levels. Furthermore, localization of proteins involved in the control of monosaccharide uptake and phosphorylation suggests that glycolysis starts at concrete points in the boar-sperm surface.

Synergistic effects of chemical enhancers on skin permeability: a case study of sodium lauroylsarcosinate and sorbitan monolaurate

Certain mixtures of chemicals are known to synergistically enhance skin permeability to drugs. Here, we report on the transport enhancing properties of mixtures of an anionic surfactant, sodium lauroylsarcosinate (NLS) and a non-ionic surfactant, sorbitan monolaurate (S20) in 1:1 phosphate buffered saline (PBS):ethanol (EtOH) solvent. Effect of 44 different compositions of NLS:S20 on skin constituents was probed by Fourier transform-infrared (FT-IR) spectroscopy while behavior of surfactant molecules in the solvent system was probed by FT-IR and NMR spectroscopy. No aggregation of NLS or S20 alone was observed in 1:1 PBS:EtOH at all concentrations studied (0-2%, w/v). However, mixtures of NLS and S20 resulted in micelle-like aggregates at certain specific compositions. Interestingly, compositions with increased aggregation showed resemblance to those that exhibited highest skin permeabilization.

Preparation of Quinoline Hexose Analogs as Novel Chloroquine-Resistant Malaria Treatments (1). Synthesis of 4-Hydroxyquinoline-.BETA.-glucosides

Quinoline hexose analogs are expected to be useful as novel agents for treatment of chloroquine-resistant malaria. Here, we report preparation of 4-hydroxy quinoline-beta-glucosides from anilines in 4 steps.

Mammalian glucose permease GLUT1 facilitates transport of arsenic trioxide and methylarsonous acid

Arsenic exposure is associated with hypertension, diabetes, and cancer. Some mammals methylate arsenic. Saccharomyces cerevisiae hexose permeases catalyze As(OH)(3) uptake. Here, we report that mammalian glucose transporter GLUT1 catalyzes As(OH)(3) and CH(3)As(OH)(2) uptake in yeast or in Xenopus laevis oocytes. Expression of GLUT1 in a yeast lacking other glucose transporters allows for growth on glucose. Yeast expressing yeast HXT1 or rat GLUT1 transport As(OH)(3) and CH(3)As(OH)(2). The K(m) of GLUT1 is to 1.2mM for CH(3)As(OH)(2), compared to a K(m) of 3mM for glucose. Inhibition between glucose and CH(3)As(OH)(2) is noncompetitive, suggesting differences between the translocation pathways of hexoses and arsenicals. Both human and rat GLUT1 catalyze uptake of both As(OH)(3) and CH(3)As(OH)(2) in oocytes. Thus GLUT1 may be a major pathway uptake of both inorganic and methylated arsenicals in erythrocytes or the epithelial cells of the blood-brain barrier, contributing to arsenic-related cardiovascular problems and neurotoxicity.

Practical production of 6-O-octanoyl-D-allose and its biological activity on plant growth

The transesterification of D-allose (the C-3 epimer of D-glucose) with vinyl octanoate using Candida antarctica lipase in tetrahydrofuran proceeded with high regioselectivity to produce 6-O-octanoyl-D-allose with nearly complete conversion. The growth-inhibiting activity of 6-O-octanoyl-D-allose on lettuce seedlings was about 6-fold greater than that of D-allose.

Preparation and biological evaluation of some 1,2-O-isopropylidene-d-hexofuranose esters

The synthesis and biological evaluation of some new glycose esters bearing the 1,2-O-isopropylidene-d-hexofuranose functionality and belonging to the 3-O-acyl-d-allose and 6-O-acyl-d-glucose series are reported. When the results concerning cell growth inhibition are compared, it appears that the 6-O-acyl-d-glucose derivatives are more active than the 3-O-acyl-d-allose compounds. Within both 6-O-acyl-d-glucose and 3-O-acyl-d-allose derivatives, butyric esters displayed the highest inhibitory effects. Inhibition of cell growth is not associated with high induction levels of erythroid differentiation, despite the fact that pivaloates induce erythroid differentiation to an extent similar to that exhibited by previously reported molecules [Bioorg. Med. Chem. Lett.1999, 9, 3153-3158].

The inhibitory effect and possible mechanisms of D-allose on cancer cell proliferation

Rare sugars are monosaccharides distributed rarely in nature, because of its very limited amount and cost, the biological effect has hardly been studied. Recently, an effective strategy for mass production of rare sugars has been developed. As a result, a wide range of study of rare sugars from the basic to applied research has become possible. For biological application of rare sugars, it is necessary to fundamentally investigate the relationships between rare sugars and living cells in terms of physiology. Therefore, we firstly examined the effect of rare sugars including D-psicose, D-allose, D-altrose and D-talitol on cell proliferation using certain cell lines in vitro. Cell growth was evaluated by MTT assay after 24-, 48- and 72-h treatment. The result shows that D-allose has a significant inhibitory effect on cancer cell proliferation in a dose-dependent manner. Although the exact mechanism remains unclear, this finding represents a novel aspect of the biological profile of D-allose and suggests that D-allose may be an effective adjuvant therapeutic agent against cancer in the future.

Isolation and characterization of a glucose/mannose/rhamnose-specific lectin from the knife bean Canavalia gladiata

A lectin with specificity toward mannose, glucose, and rhamnose has been isolated from the legumes of the knife bean Canavalia gladiata. The lectin is composed of two identical 30-kDa subunits with substantial N-terminal sequence similarity to Concanavalin A (Con A). It was purified by affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono S, and gel filtration by fast protein liquid chromatography on Superdex 200. Compared with Con A, knife bean lectin started to stimulate [methyl-(3)H]thymidine uptake by mouse splenocytes at a lower concentration, and more potently inhibited proliferation of L1210 leukemia cells. In contrast to Con A, the mitogenic activity of knife bean lectin toward mouse splenocytes, but not its antiproliferative activity toward tumor cells, could be abrogated by 250 mM glucose. Both mitogenic and antiproliferative activities of Con A were abolished by glucose. The lectin inhibited HIV-1 reverse transcriptase with an IC(50) of 35 microM and cell-free translation in a rabbit reticulocyte lysate system with an IC(50) of 2.08 microM. The lectin did not exhibit antifungal activity.

Effects of hexoses on in vitro oocyte maturation and embryo development in pigs

The objective was to determine the effects of supplementing hexoses in oocyte maturation and embryo culture medium on in vitro maturation (IVM) and in vitro fertilization (IVF) of porcine oocytes and in vitro development of in vitro produced (IVP) porcine embryos. In the first experiment, oocytes were matured in vitro in modified North Carolina State University (NCSU)-37 medium, supplemented with hexoses (glucose, fructose or galactose) at various concentrations: 0 (control), 2.5, 5.5 and 10 mM. Supplementing the maturation medium with either glucose or fructose (5.5 mM) increased the percentages of oocytes that matured to metaphase II (79.4 and 70.2%, respectively), as compared with the control group (P < 0.05). However, supplementing galactose had no effects on meiotic maturation and fertilization. In the second experiment, cleaved embryos were collected 3 days after IVF of oocytes matured in the maturation medium supplemented with 5.5 mM of glucose; they were cultured for an additional 4 days in modified NCSU-37 medium, supplemented with 5.5mM of glucose, fructose or galactose. The incidence of blastocyst formation was higher (P < 0.05) in the glucose and fructose groups (18.6 and 18.2%, respectively) than in the galactose group and non-supplemented control group (12.9 and 9.2%). Moreover, fructose supplementation increased the total cell number/blastocyst (48.0 versus 37.6) and reduced the index of DNA-fragmented nucleus in the blastocysts (7.6% versus 11.8%), as compared with glucose supplementation (P < 0.05). In conclusion, fructose was a practical alternative to glucose for supporting IVM of porcine oocytes and fructose was superior to glucose for producing high-quality porcine embryos in vitro.

The heterotrimeric G-protein GanB(alpha)-SfaD(beta)-GpgA(gamma) is a carbon source sensor involved in early cAMP-dependent germination in Aspergillus nidulans

The role of heterotrimeric G-proteins in cAMP-dependent germination of conidia was investigated in the filamentous ascomycete Aspergillus nidulans. We demonstrate that the G alpha-subunit GanB mediates a rapid and transient activation of cAMP synthesis in response to glucose during the early period of germination. Moreover, deletion of individual G-protein subunits resulted in defective trehalose mobilization and altered germination kinetics, indicating that GanB(alpha)-SfaD(beta)-GpgA(gamma) constitutes a functional heterotrimer and controls cAMP/PKA signaling in response to glucose as well as conidial germination. Further genetic analyses suggest that GanB plays a primary role in cAMP/PKA signaling, whereas the SfaD-GpgA (G betagamma) heterodimer is crucial for proper activation of GanB signaling sensitized by glucose. In addition, the RGS protein RgsA is also involved in regulation of the cAMP/PKA pathway and germination via attenuation of GanB signaling. Genetic epistatic analyses led us to conclude that all controls exerted by GanB(alpha)-SfaD(beta)-GpgA(gamma) on conidial germination are mediated through the cAMP/PKA pathway. Furthermore, GanB may function in sensing various carbon sources and subsequent activation of downstream signaling for germination.

Synthesis, surface active and antimicrobial properties of new alkyl 2,6-dideoxy-l-arabino-hexopyranosides

Synthesis of alkyl 2,6-dideoxy-L-arabino-hexopyranosides was accomplished by the reaction of 1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol with fatty alcohols in dichloromethane, catalyzed by triphenylphosphine hydrobromide. Reaction with octanol and dodecanol gave the corresponding alpha-glycosides in 50% and 42% yield, the beta-glycosides in 20% and 21% yield and the alpha-anomer of the Ferrier product in 10% and 9% yield, respectively. Deacetylation of the alpha-/beta-glycosides with sodium methoxide in methanol afforded the amphiphilic L-arabino-hexopyranosides in 94-99% yield. The surface tension at the air-water interface of the octyl L-glycosides and of the dodecyl alpha-L-glycoside aqueous solutions at 35 degrees C was measured with a du Noüy ring tensiometer and surface properties such as critical micelle concentration (CMC), relative surface excess, molecular area at the interface and Gibbs micellization free energy were evaluated. The stereochemistry of the hexopyranoside ring in unimers and aggregates is correlated to the hydrophobicity and packing efficiency on the air-water interface. The antibacterial and antifungal activities of the surface-active glycosides were evaluated using the paper disk diffusion method. The dodecyl alpha-L-arabino-hexopyranoside was quite active over Bacillus cereus and Bacillus subtilis, while low activity was found for this glycoside over Enterococcus faecalis and Listeria monocytogenes. The octyl glycosides tested showed low activity over almost all the above-mentioned bacteria, and also over the fungus Candida albicans. No inhibition of Salmonella enteritidis and of the filamentous fungus Aspergillus niger was detected for any of the compounds tested.

Effect of hexoses and gonadotrophin supplementation on bovine oocyte nuclear maturation during in vitro maturation in a synthetic follicle fluid medium

In vitro oocyte maturation (IVM) culture conditions have been relatively unchanged over the past few decades and remain suboptimal. In contrast, studies of the in vivo environment have led to significant improvements to in vitro embryo culture technologies. The aim of the present study was to determine the effect of maturing bovine cumulus–oocyte complexes (COCs) in medium based on the composition of bovine follicular fluid (Bovine VitroMat; Cook Australia, Eight Mile Plain, Qld, Australia). In particular, the effect of different glucose concentrations and glucosamine supplementation on meiotic maturation was determined. Culturing COCs in the presence of gonadotrophins in Bovine VitroMat, containing either physiological glucose concentrations (2.3 mm) or 5.6 mm (equivalent to levels in Tissue Culture Medium 199 (TCM199)) supplemented with glucosamine resulted in comparable cumulus expansion to COCs cultured in TCM199 plus gonadotrophins. However, nuclear maturation was 1.3-fold lower in Bovine VitroMat cultures containing 2.3 mm glucose compared with 5.6 mm glucose and this effect was independent of glucosamine supplementation. Investigations into the effects of different glucose concentrations and gonadotrophin supplementation during the initial 6 h of maturation demonstrated that COCs cultured in Bovine VitroMat with 5.6 mm glucose without gonadotrophins had a twofold acceleration of the rate of meiotic resumption, yet the rate of polar body formation was decreased by approximately 20% compared with cultures in 2.3 mm glucose and TCM199. However, this effect was not seen when COCs were cultured for the initial 16 h in Bovine VitroMat + 5.6 mm minus gonadotrophins or in Bovine VitroMat + 2.3 mm glucose ± gonadotrophins. These data demonstrate that glucose concentrations and the timing of the introduction of gonadotrophin during IVM have variable effects on nuclear maturation. Manipulation of glucose concentrations may be a mechanism to influence oocyte meiotic progression and may lead to the development of improved IVM systems, allowing for an increased developmental capacity of bovine oocytes.

Hexose sugars differentially alter collagen gene expression and synthesis in fibroblasts derived from granulation tissue, hypertrophic scar and keloid

Clinical observations have suggested that sugar and honey enhance granulation tissue formation and in vitro studies have shown that monosaccharide sugars stimulate mesenchymal and endothelial cells. In this study, the effects of glucose, fructose, galactose and mannose on type I and type III collagen gene expression and synthesis were studied in granulation tissue, hypertrophic scar and keloid fibroblast cultures. Glucose elevated both type I and type III collagen mRNAs in hypertrophic scar fibroblasts. Fructose increased type III collagen mRNA almost sevenfold in granulation tissue fibroblasts. Galactose caused an increase in type I and type III collagen mRNAs in granulation tissue fibroblasts and hypertrophic scar fibroblasts but, in contrast, mannose decreased type I and type III collagen levels in hypertrophic scar and keloid fibroblasts. Analysis of aminoterminal propeptides of type I and type III collagen (PINP and PIIINP) revealed that glucose decreased the amount of PINP in granulation tissue and keloid fibroblasts, whilst fructose decreased the amount in all the fibroblast cell lines studied. Galactose caused a decrease in the synthesis of type I collagen in all cell lines but a decrease was seen in type III collagen only in hypertrophic scar fibroblasts. Mannose decreased the amount of PINP in all cell lines but a decrease in the amount of PIIINP was seen only in granulation tissue fibroblasts. The effect of sugars on the ratio type I/type III collagen was negligible or decreasing with the exception of galactose, which increased the ratio in hypertrophic scar fibroblasts. The results suggest that glucose, fructose and galactose have no significant value in the stimulation of collagen synthesis in vitro. Mannose may have value in the prevention or treatment of abnormal scars.

Nonpeptide luteinizing hormone-releasing hormone antagonists derived from erythromycin A: design, synthesis, and biological activity of cladinose replacement analogues

The design and synthesis of a series of 11,12-cyclic carbamate derivatives of 6-O-methylerythromycin A that are novel, nonpeptide LHRH antagonists, is described. The macrolide antagonist 1, discovered during a screen of our chemical repository, was compared to a macrocyclic peptide antagonist 2 using molecular modeling, thus providing a model for the design of more potent antagonists. Medicinal chemistry efforts to find a replacement for cladinose at position 3 of the erythronolide core provided a series of oxazolidinone carbamates that were equally as active as the cladinose-containing parent macrolides. The descladinose LHRH antagonist 14 has 1-2 nM affinity for both rat and human LHRH receptors and is a potent inhibitor of LH release (pA2 = 8.76) in vitro. In vivo, 14 was found to produce a dose-dependent suppression of LH in male castrate rats via both i.v. and p.o. dosing.

Interaction of substituted hexose analogues with the Trypanosoma brucei hexose transporter

Glucose metabolism is essential for survival of bloodstream form Trypanosoma brucei subspecies which cause human African trypanosomiasis (sleeping sickness). Hexose analogues may represent good compounds to inhibit glucose metabolism in these cells. Delivery of such compounds to the parasite is a major consideration in drug development. A series of D-glucose and D-fructose analogues were developed to explore the limits of the structure-activity relationship of the THT1 hexose transporter of bloodstream form African trypanosomes, a portal that might be exploited for drug uptake. D-glucose analogues with substituents at the C2 and C6 position continued to interact with the exofacial hexose binding site of the transporter. There was a limit to the size at C6 which still permitted recognition, although compounds carrying large groups at position C2 were still recognised. However, radiolabelled N-acetyl-D-[1-14C] glucosamine was not internalised by trypanosomes, in spite of the ability of this compound to inhibit glucose uptake, indicating that there is a limit to the size of C2 substituent that allows translocation. Addition of an alkylating group (bromoacetyl) at position C2 in the D-glucose series and at position 6 in the D-fructose set, created two analogues which interact with the transporter and kill trypanosomes in vitro. This indicates that inhibition of the transporter may be a good means of killing trypanosomes.

Amelioration by active hexose correlated compound of endocrine disturbances induced by oxidative stress in the rat

OBJECTIVE

Active hexose correlated compound (AHCC), an extract derived from fungi of Basidiomycetes family, has been found to be a potent antioxidant. Since the secretion of some hormones can be affected by reactive oxygen species, the objective of this study was to examine how ferric nitrilotriacetate (FeNTA), which generates hydroxyl radicals in vivo, modulates the hormone secretion and the effects of AHCC.

METHODS

AHCC at 3 % in drinking water was given to male rats for one week, and the animals were decapitated at different time intervals after the treatment with FeNTA intraperitoneally. Serum levels of hormones (corticosterone, testosterone, thyroxine and triiodothyronine), adrenal ascorbic acid as well as changes in hepatic oxidative status were evaluated by immunoassay and spectrometry.

RESULTS

Serum corticosterone levels increased significantly following FeNTA treatment, while AHCC reduced the increased levels to normal. Adrenal ascorbic acid levels that reflect ACTH secretion, were decreased by FeNTA and restored to normal by AHCC. Serum levels of testosterone and thyroxine (T4) decreased rapidly after FeNTA treatment, while AHCC pretreatment prevented this fall. Serum triiodothyroxine (T3) levels remained unchanged either by FeNTA or AHCC treatment. The hepatic oxidized glutathione, glutathione-related enzymes and also serum lipid peroxide were greatly enhanced after FeNTA treatment. All of these changes were restored to normal by AHCC pretreatment.

CONCLUSION

FeNTA induces various endocrine disorders and AHCC ameliorates these effects by acting as an antioxidant.

The mitochondrial complex I inhibitor annonacin is toxic to mesencephalic dopaminergic neurons by impairment of energy metabolism

The death of dopaminergic neurons induced by systemic administration of mitochondrial respiratory chain complex I inhibitors such as 1-methyl-4-phenylpyridinium (MPP(+); given as the prodrug 1-methyl-1,2,3,6-tetrahydropyridine) or the pesticide rotenone have raised the question as to whether this family of compounds are the cause of some forms of Parkinsonism. We have examined the neurotoxic potential of another complex I inhibitor, annonacin, the major acetogenin of Annona muricata (soursop), a tropical plant suspected to be the cause of an atypical form of Parkinson disease in the French West Indies (Guadeloupe). When added to mesencephalic cultures for 24 h, annonacin was much more potent than MPP(+) (effective concentration [EC(50)]=0.018 versus 1.9 microM) and as effective as rotenone (EC(50)=0.034 microM) in killing dopaminergic neurons. The uptake of [(3)H]-dopamine used as an index of dopaminergic cell function was similarly reduced. Toxic effects were seen at lower concentrations when the incubation time was extended by several days whereas withdrawal of the toxin after a short-term exposure (<6 h) arrested cell demise. Unlike MPP(+) but similar to rotenone, the acetogenin also reduced the survival of non-dopaminergic neurons. Neuronal cell death was not excitotoxic and occurred independently of free radical production. Raising the concentrations of either glucose or mannose in the presence of annonacin restored to a large extent intracellular ATP synthesis and prevented neuronal cell demise. Deoxyglucose reversed the effects of both glucose and mannose. Other hexoses such as galactose and fructose were not protective. Attempts to restore oxidative phosphorylation with lactate or pyruvate failed to provide protection to dopaminergic neurons whereas idoacetate, an inhibitor of glycolysis, inhibited the survival promoting effects of glucose and mannose indicating that these two hexoses acted independently of mitochondria by stimulating glycolysis. In conclusion, our study demonstrates that annonacin promotes dopaminergic neuronal death by impairment of energy production. It also underlines the need to address its possible role in the etiology of some atypical forms of Parkinsonism in Guadeloupe.

Suppressive effects of Active Hexose Correlated Compound on the increased activity of hepatic and renal ornithine decarboxylase induced by oxidative stress

Active Hexose Correlated Compound (AHCC), an extract derived from fungi of Basidiomycetes family has been shown to act as a biological response modifier in various disorders. In our present study, ferric nitrilotriacetate (Fe-NTA), which generates hydroxyl radicals in vivo, was given intraperitoneally to rats and AHCC was tested for its ability to suppress oxidative stress and the activity of ornithine decarboxylase (ODC) in the liver and kidney. Substantial increments in glutathione-related enzymes including glutathione reductase, glutathione peroxidase activity as well as oxidized glutathione contents were shown in the liver at 12 h after treatment with Fe-NTA (7.5 mg Fe/kg body weight). Effects of oxidative stress induced by Fe-NTA were also demonstrated by the increase in serum lipid peroxidation, aminotransferases and urinary 8-hydroxy-2'-deoxyguanosine. However, the increases in these parameters were restored to normal in AHCC-pretreated rats. The ODC activity in the liver and kidney was significantly increased by Fe-NTA, while the increased ODC activity induced by Fe-NTA was normalized in AHCC-pretreated rats. These results suggest AHCC acts as a potent antioxidant and protects against disorders induced by oxidative stresses.

Influence of surfactant hydrophobicity on the detachment of Escherichia coli O157:H7 from lettuce

The influence of surfactant hydrophobicity on detachment of Escherichia coli O157:H7 from lettuce was determined. Lettuce pieces inoculated with the pathogen were rinsed with Tween and Span surfactants of different hydrophobicity. Of the Tweens, only Tween 85, the Tween with the lowest hydrophile/lipophile balance (HLB), significantly detached the pathogen from lettuce surface. Span 85 (the surfactant with the lowest HLB studied) exhibited the greatest ability among surfactants tested to detach cells from lettuce. This surfactant removed cells attached to the leaf cuticle but not to the cut edge, and caused no detectable reduction in viability of cells remaining on the lettuce. Treatment with Span 85 did not detach cells when they were allowed to attach in the presence of calcium ions. The combination of NaCl/NaHCO3 (pH 10) and Span 85 did not detach cells possibly due to reduced hydrophobicity of the Span at this pH. This study suggests that surfactants of low HLB disrupt hydrophobic interactions between E. coli O157:H7 and the lettuce surface but cannot cause release of cells adhering to hydrophilic structures such as cut or damaged tissue.

Nifedipine loaded chitosan microspheres prepared by emulsification phase-separation

A high yield of nifedipine-chitosan microspheres could be obtained using an emulsification phase-separation method. A high level of entrapment of nifedipine in the microspheres was achieved. The microspheres exhibited excellent swelling properties. Differential scanning calorimetry, X-ray diffractometry, and scanning electron microscopy confirmed that at 1.84% loading, nifedipine was dispersed molecularly. The microspheres exhibited faster release at low loadings compared to high loadings. Fitting the data to the coupled Fickian/case II equation, showed that at low loadings polymer relaxation coefficients (k2) were high. As the polymer content increased in the microspheres, the value of n (diffusional exponent characteristic of the release mechanism) approached one, which is indicative of zero order.

D-xylose metabolism in Hypocrea jecorina: loss of the xylitol dehydrogenase step can be partially compensated for by lad1-encoded L-arabinitol-4-dehydrogenase

With the goal of the genetic characterization of the D-xylose pathway in Hypocrea jecorina (anamorph: Trichoderma reesei), we cloned the xdh1 gene, encoding NAD-xylitol dehydrogenase, which catalyzes the second step of fungal D-xylose catabolism. This gene encodes a 363-amino-acid protein which has a mass of 38 kDa, belongs to the zinc-containing alcohol dehydrogenase family, exhibits high sequence identity to the published sequences of xylitol dehydrogenases from yeast origins, but contains a second, additional binding site for Zn2+. The enzyme catalyzed the NAD-dependent oxidation of xylitol and D-sorbitol and the NADH-dependent reduction of D-xylulose and D-fructose. No activity was observed with NADP, L-arabinose, or L-arabinitol. A single 1.4-kb transcript was formed during growth on xylan, D-xylose, L-arabinose, L-arabinitol and, at a lower abundance, xylitol, D-galactose, galactitol, and lactose but not on D-glucose and glycerol. xdh1 deletion mutants exhibited 50% reduced growth rates on D-xylose, whereas growth rates on xylitol remained unaltered. These mutants contained 30% of the xylitol dehydrogenase activity of the parent strain, indicating the presence of a second xylitol dehydrogenase. This activity was shown to be due to lad1-encoded L-arabinitol-4-dehydrogenase, because H. jecorina xdh1 lad1 double-deletion strains failed to grow on D-xylose or xylitol. In contrast, lad1 deletion strains of H. jecorina grew normally on these carbon sources. These results show that H. jecorina contains a single xylitol dehydrogenase which is encoded by xdh1 and is involved in the metabolism of D-xylose and that lad1-encoded L-arabinitol-4-dehydrogenase can compensate for it partially in mutants with a loss of xdh1 function.

Active hexose correlated compound enhances resistance to Klebsiella pneumoniae infection in mice in the hindlimb-unloading model of spaceflight conditions

Previous studies have demonstrated that resistance to infection is decreased in Swiss Webster female mice maintained in the hindlimb-unloading model (Aviles H, Belay T, Fountain K, Vance M, and Sonnenfeld G. J Appl Physiol 95: 73-80, 2003; Belay T, Aviles H, Vance M, Fountain K, and Sonnenfeld G. J Allergy Clin Immunol 110: 262-268, 2002). This is a model of some of the aspects of spaceflight conditions, including lack of load bearing on hindlimbs and a fluid shift to the head. Active hexose correlated compound (AHCC), extracted from Basidiomycete mushrooms, has been shown to induce enhancement of immune responses, including enhanced natural killer activity. In the present study, AHCC was orally administered to mice to determine whether the treatment could decrease immunosuppression and mortality of mice maintained in the hindlimb-unloaded model and infected with Klebsiella pneumoniae. The results of the present study showed that administration of AHCC by gavage for 1 wk (1 g/kg body wt) before suspension and throughout the 10-day suspension period yielded significant beneficial effects for the hindlimb-unloaded group, including 1). decreased mortality, 2). increased time to death, and 3). increased ability to clear bacteria. The results suggest that AHCC can decrease the deleterious effects of the hindlimb-unloading model on immunity and resistance to infection.

Genotoxic and antigenotoxic effects of catechin and tannins from the bark of Hamamelis virginiana L. in metabolically competent, human hepatoma cells (Hep G2) using single cell gel electrophoresis

The genotoxic and antigenotoxic activities of catechin, hamamelitannin and two proanthocyanidin fractions prepared from the bark of Hamamelis virginiana L. were investigated in a human derived, metabolically competent hepatoma cell line (Hep G2) using single cell gel electrophoresis (SCGE) for the detection of DNA-damage. DNA-migration was calculated as Olive tail moment (OTM). Catechin and a low-molecular weight proanthocyandin fraction (W(M)) caused only slight increases of OTM up to concentrations of 166 microg/ml whereas hamamelitannin and the proanthocyandin fraction with higher molecular weight (W(A)) led to a two-fold enhancement of OTM at the same concentrations. These effects were dose-independent. Treatment of the cells with the test compounds in a dose-range of 2-166 microg/ml prior to the exposure to benzo(a)pyrene (B(a)P, 10 microM, 2.5 microg/ml) led to a significant reduction of induced DNA damage which was dose-dependent for all test compounds, except for hamamelitannin. The inhibitory effects of proanthocyanidins were stronger than those of catechin and hamamelitannin; the lowest effective concentrations were about 2 microg/ml. In order to clarify the mechanisms of protection, possible effects of the test compounds on enzymes involved in toxification and detoxification of B(a)P were investigated. While B(a)P toxification by cytochrome P450 was not inhibited by the test compounds, detoxification by glutathion-S-transferase (GST) was induced by catechin and W(M). Combination experiments with the ultimate metabolite of B(a)P, (+/-)-anti-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE; 5 microM, 1.5 microg/ml), revealed strong inhibitory effects, indicating that the observed protective effects were caused by scavenging of the ultimate mutagen by the test compounds. Exposure of Hep G2 cells to the test compounds after B(a)P treatment did not influence B(a)P induced DNA damage, demonstrating that repair mechanisms were not affected.

Pleurotus Eous mushroom lectin (PEL) with mixed carbohydrate inhibition and antiproliferative activity on tumor cell lines

A novel Pleurotus eous mushroom lectin (PEL) having mixed binding specificity was purified to homogeneity from the fruitbodies of P. eous. The lectin showed monomer weight of 16 kDa and was a glycoprotein having a 9% neutral sugar content. The antiproliferative activity of PEL was tested on four human tumor cell lines. A 50% inhibition of proliferation was demonstrated in MCF-7, K562 and Hep2 cell lines at the lowest concentration (2 microg/ml) of lectin tested. SK-N-MC cell line showed 50% inhibition at 50 microg/ml of PEL. The inhibitory activity of PEL was not associated with toxicity to cell lines.

The effects of pressure-sensitive adhesives and solubilizers on the skin permeation of testosterone from a matrix-type transdermal delivery system

Matrix-type transdermal delivery systems of testosterone (TS) were formulated with three different pressure-sensitive adhesives (PSA). The effects of PSA, skin permeation enhancers, and solubilizers on the rat skin permeation rate of TS were systematically investigated. Without a solubilizer, the skin permeation rate of TS reached its maximum value when only 2% of TS was loaded in the matrix and the crystal formation in the matrix was very rapid and severe. Two surfactants differing in their hydrophile-lipophile balance (HLB) number were, therefore, considered. Span 80, which was of the lower HLB number, was more effective than Tween 80 in increasing the solubility, and thereby increasing the permeation rate of TS. Moreover, the concentrations of both the solubilizer and the skin permeation enhancer affected the skin permeation rate. Thus, the highest skin permeation rate (4.14 micrograms/cm2/hr) was achieved when 2% TS was loaded in DuroTak 87-2516 together with 10% Span 80 and 3% dodecylamine, the permeation enhancer. In vivo study showed that the application of an experimental patch on rat abdominal skin resulted in a prompt and significantly higher plasma concentration of TS than that of a commercial product (Testoderm) designed to apply on the scrotal skin. The area under the curve (AUC) increased linearly as the loading dose of TS increased up to 6%. Thus, based on these results, a non-scrotal matrix-type transdermal delivery system of TS could be developed.