Next Generation Chemiluminescent Probes for Antimalarial Drug Discovery.

Malaria is caused by parasites of the Plasmodium genus and remains one of the most pressing human health problems. The spread of parasites resistant to or partially resistant to single or multiple drugs, including frontline antimalarial artemisinin and its derivatives, poses a serious threat to current and future malaria control efforts. In vitro drug assays are important for identifying new antimalarial compounds and monitoring drug resistance. Due to its robustness and ease of use, the [3H]-hypoxanthine incorporation assay is still considered a gold standard and is widely applied, despite limited sensitivity and the dependence on radioactive material. Here, we present a first-of-its-kind chemiluminescence-based antimalarial drug screening assay. The effect of compounds on P. falciparum is monitored by using a dioxetane-based substrate (AquaSpark ß-D-galactoside) that emits high-intensity luminescence upon removal of a protective group (ß-D-galactoside) by a transgenic ß-galactosidase reporter enzyme. This biosensor enables highly sensitive, robust, and cost-effective detection of asexual, intraerythrocytic P. falciparum parasites without the need for parasite enrichment, washing, or purification steps. We are convinced that the ultralow detection limit of less than 100 parasites of the presented biosensor system will become instrumental in malaria research, including but not limited to drug screening.

Prophylactic Antiviral Activity of Sulfated Glycomimetic Oligomers and Polymers.

In this work, we investigate the potential of highly sulfated synthetic glycomimetics to act as inhibitors of viral binding/infection. Our results indicate that both long-chain glycopolymers and short-chain glycooligomers are capable of preventing viral infection. Notably, glycopolymers efficiently inhibit Human Papillomavirus (HPV16) infection in vitro and maintain their antiviral activity in vivo, while the glycooligomers exert their inhibitory function post attachment of viruses to cells. Moreover, when we tested the potential for broader activity against several other human pathogenic viruses, we observed broad-spectrum antiviral activity of these compounds beyond our initial assumptions. While the compounds tested displayed a range of antiviral efficacies, viruses with rather diverse glycan specificities such as Herpes Simplex Virus (HSV), Influenza A Virus (IAV), and Merkel Cell Polyomavirus (MCPyV) could be targeted. This opens new opportunities to develop broadly active glycomimetic inhibitors of viral entry and infection.

Biological Activities of Lactose-Derived Prebiotics and Symbiotic with Probiotics on Gastrointestinal System.

Lactose-derived prebiotics provide wide ranges of gastrointestinal comforts. In this review article, the probable biochemical mechanisms through which lactose-derived prebiotics offer positive gastrointestinal health are reported along with the up-to-date results of clinical investigations; this might be the first review article of its kind, to the best of our knowledge. Lactose-derived prebiotics have unique biological and functional values, and they are confirmed as 'safe' by the Food and Drug Administration federal agency. Medical practitioners frequently recommend them as therapeutics as a pure form or combined with dairy-based products (yoghurt, milk and infant formulas) or fruit juices. The biological activities of lactose-derived prebiotics are expressed in the presence of gut microflora, mainly probiotics (Lactobacillus spp. in the small intestine and Bifidobacterium spp. in the large intestine). Clinical investigations reveal that galacto-oligosaccharide reduces the risks of several types of diarrhea (traveler's diarrhea, osmotic diarrhea and Clostridium difficile associated relapsing diarrhea). Lactulose and lactosucrose prevent inflammatory bowel diseases (Crohn's disease and ulcerative colitis). Lactulose and lactitol reduce the risk of hepatic encephalopathy. Furthermore, lactulose, galacto-oligosaccharide and lactitol prevent constipation in individuals of all ages. It is expected that the present review article will receive great attention from medical practitioners and food technologists.

Trifolin induces apoptosis via extrinsic and intrinsic pathways in the NCI-H460 human non-small cell lung-cancer cell line.

BACKGROUND: Trifolin (kaempferol-3-O-galactoside), which is a galactose-conjugated flavonol, exhibits antifungal and anticancer effects. However, the mechanisms underlying its anticancer activities have not yet been examined. PURPOSE: In this study, the anticancer effects of trifolin were examined in human lung cancer cells. METHODS: Cytotoxicity was determined by evaluating cell viability. Apoptosis was analyzed through flow cytometry and western blotting analysis. Death receptors and inhibitors of apoptosis were evaluated through RT-PCR. RESULTS: Trifolin induced apoptosis in NCI-H460 human non-small cell lung cancer (NSCLC) cells by inhibiting the survival pathway and inducing the intrinsic and extrinsic apoptosis pathways. Trifolin decreased levels of Akt/p-Akt, whereas levels of expression of phosphatidylinositide 3-kinase (PI3K), cyclin D1, cyclin E, and cyclin A were not altered. Trifolin initiated cytochrome c release by inducing mitochondrial outer membrane permeabilization (MOMP). Trifolin increased Bcl-2-associated X protein (Bax) levels and decreased b-cell lymphoma 2 (Bcl-2) levels, while the levels of Bcl-xL were not altered. In addition, trifolin increased the levels of the death receptor involving the Fas/Fas ligand (FasL) and Fas-associated protein with the death domain (FADD), which consequently activated caspase-8, caspase-9, caspase-3, and the proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). CONCLUSION: These results suggested that trifolin induced apoptosis via death receptor-dependent and mitochondria-dependent pathways and that trifolin can be used as a therapeutic agent in human lung cancer.

Anticancer potential of rhamnocitrin 4'-ß-D-galactopyranoside against N-diethylnitrosamine-induced hepatocellular carcinoma in rats.

The hepatoprotective activity of flavonoid rhamnocitrin 4'-ß-D-galactopyranoside (RGP) obtained from leaves of Astragalus hamosus L. against N-diethylnitrosamine (DENA)-induced hepatic cancer in Wistar albino rats was evaluated. Hepatic cancer in rats was induced by single-dose intraperitoneal administration of DENA (200 mg/kg). Induction of hepatic cancer was confirmed after 7 days of DENA administration by measurement of elevated level of serum α-feto protein (AFP). Administration of DENA in a single dose lofted the levels of serum biochemical parameters like alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, total protein and AFP. Antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and lipid per oxidation (LPO) were annealed significantly by administration of RGP in a dose-dependant manner. The histopathological examination of rat liver section was found to reinforce the biochemical observations significantly. It was observed that a substantial and dose-dependent reversal of DENA-diminished activity of antioxidant enzymes like SOD, CAT, GPx, GST and the reduced DENA-elevated level of LPO with a marked change. Any elevation in the levels of serum markers along with suppression of free radical formation by scavenging the hydroxyl radicals is significantly prevented by RGP. It also modulates the levels of LPO and perceptibly increases the endogenous antioxidant enzymes level in DENA-induced hepatocellular carcinogenesis. The findings suggest that RGP prevents hepatocellular carcinoma by suppressing the marked increase in the levels of serum marker enzymes, and suppresses the free radical by scavenging hydroxyl radicals.

Bioguided isolation of myricetin-3-O-ß-galactopyranoside with antinociceptive activity from the aerial part of Davilla elliptica St.-Hil.

ETHNOPHARMACOLOGICAL RELEVANCE: Davilla elliptica St.-Hil. (Dilleniaceae) is a medicinal plant traditionally used in Brazil to treat inflammatory processes, to relieve pain, as diuretic, gastro- and hepatoprotective agents. AIM OF THE STUDY: To undertake the fractionation of the ethanolic extract from Davilla elliptica leaves guided by an antinociceptive assay. MATERIALS AND METHODS: The antinociceptive activity was evaluated through the formalin test in mice. Extract fractionation was performed by percolation through silica gel and partition between immiscible solvents, followed by successive column chromatography over Sephadex LH-20 and preparative RP-HPLC. Structure elucidation of the isolated compound was accomplished by spectroscopic data. RESULTS: The EtOAc and MeOH fractions derived from the crude extract reduced significantly the licking time in the late phase of the formalin test. The bioguided fractionation of the MeOH fraction resulted in the isolation of myricetin-3-O-ß-galactopyranoside, which produced significant inhibition on nociception induced by formalin (ID50=0.26 mg/kg; p.o.). CONCLUSIONS: These results point out that myricetin-3-O-ß-galactopyranoside contributes for the antinociceptive effect of Davilla elliptica extract, a constituent considerably more potent than diclofenac, employed as reference drug.

Perinatal and postweaning exposure to galactooligosaccharides/inulin prebiotics induced biomarkers linked to tolerance mechanism in a mouse model of strong allergic sensitization.

Food allergies are increasing, and no treatment exists, thus enhancing interest in prebiotic strategies. This study aimed to analyze the preventive effects of prebiotic feeding during perinatal and postweaning periods in a mouse model of allergy by studying biomarkers related to tolerance (IgG2a, IgA, IFN-γ, TGF-ß, and IL-10), to allergy (IgE, IgG1, IL-4, IL-17, symptoms), and to microbiota (propionate and MyD88). Balb/c mice, both dams and their pups, were fed a diet supplemented with (+Prb) or without (-Prb) GOS/inulin prebiotics. Mice were then sensitized with allergens. Regardless of diet, sensitized mice exhibited similar levels of IgE, IgG1, CD-23, IL-4, IL-17, and symptoms. However, in comparison to -Prb-sensitized mice, +Prb-sensitized mice displayed higher concentrations of total IgG2a (6669 ± 1788 vs 3696 ± 1326 fluorescence units, p < 0.005), specific IgA (285 ± 26 vs 156 ± 9 fluorescence units, p < 0.01), IFN-γ (3194 ± 424 vs 1853 ± 434 pg/mL, p < 0.01), IL-10 (777 ± 87 vs 95 ± 136 pg/mL, p < 0.005), TGF-ß (4853 ± 1959 vs 243 ± 444 pg/mL, p < 0.01), MyD88 (0.033 ± 0.019 vs 0.009 ± 0.004 relative expression, p < 0.01), and propionate (4.15 ± 0.8 vs 2.9 ± 1.15 µmol, p < 0.05). In a mouse model of allergy, prebiotic exposure during perinatal and postweaning periods induced the highest expression of biomarkers related to tolerance without affecting biomarkers related to allergy.

Betula pendula Roth leaves: gastroprotective effects of an HPLC-fingerprinted methanolic extract.

In this study, a methanolic extract of Betula pendula leaves (BLE) was investigated for its gastroprotective effects against 90% ethanol-induced ulcer in rats. Oral pretreatment of rats with BLE (100, 200 and 400 mg kg(- 1)) significantly reduced the incidence of gastric lesions induced by ethanol administration as compared with misoprostol (0.50 mg kg(- 1)). Furthermore, BLE inhibited the increase in malondialdehyde (MDA) and prevented depletion of total sulhydryl and non-protein sulhydryl groups in rat stomach homogenate when compared with ethanol group. With regard to the effect of lipid peroxidation in vitro, BLE showed the ability to reduce methyl linoleate autoxidation. Chemical characterisation of the main biologically active constituents of BLE was also achieved by means of high-performance liquid chromatography with photodiode array and mass spectrometry detection, showing the presence of myricetin-3-O-galactoside, quercetin glycosides, kaempferol glycosides.

Delphinidin-3-O-galactoside protects mouse hepatocytes from (-)-epigallocatechin-3-gallate-induced cytotoxicity via up-regulation of heme oxygenase-1 and heat shock protein 70.

Delphinidin-3-O-galactoside (D3G) is a water-soluble anthocyanin with antioxidant activity. (-)-Epigallocatechin-3-gallate (EGCG) is also known as a powerful antioxidant but concomitantly possesses a prooxidative property. We hypothesized that D3G is capable of protecting the EGCG-induced cytotoxicity and endoplasmic reticulum (ER) stress via inducing self-protective proteins and antioxidant enzymes. (-)-Epigallocatechin-3-gallate (200-500 µM) dose dependently decreased the viability of hepa1c1c-7 mouse hepatocytes, whereas D3G (50-500 µM) did not change it. Pretreatment with D3G significantly suppressed EGCG-induced cytotoxicity in a time-dependent manner (0, 6, and 24 hours). (-)-Epigallocatechin-3-gallate drastically decreased heme oxygenase-1 and heat shock protein 70 messenger RNA (mRNA) levels, whereas, pretreatment with D3G markedly attenuated their down-regulations. Delphinidin-3-O-galactoside remarkably decreased EGCG-induced ER stress responses such as C/EBP-homologus protein mRNA expression and X-box-binding protein-1 mRNA splicing. Taken together, our data suggest that D3G is capable of masking the EGCG-induced cytotoxicity and ER stress, presumably through up-regulation of antioxidant enzymes and heat shock proteins.

Neuroprotective effects of Salidroside and its analogue tyrosol galactoside against focal cerebral ischemia in vivo and H2O2-induced neurotoxicity in vitro.

Salidroside (Sal) is a natural antioxidant extracted from the root of Rhodiola rosea L. that elicits neuroprotective effects in vivo and in vitro. Tyrosol galactoside (Tyr), an analog of Sal, was recently synthesized in our laboratory. The purpose of the current study was to investigate and compare the neuroprotective effects of Sal and Tyr against focal cerebral ischemia in vivo and H(2)O(2)-induced neurotoxicity in vitro. Sal and Tyr significantly prevented a cerebral ischemic injury induced by a 2 h middle cerebral artery occlusion and a 24 h reperfusion in rats in vivo. Furthermore, the oxidative insult was markedly attenuated by treatments of Sal and Tyr in the cultured rat cortical neurons after a 30 min exposure to 50 µM of H(2)O(2). Western blot analysis revealed that Sal and Tyr decreased the expression of Bax and restored the balance of pro- and anti-apoptotic proteins. The neuroprotective effects of these two analogues show that Tyr has a better antioxidative action compared with Sal both in vivo and in vitro, and suggest that the antioxidant activity of Sal and Tyr may be partly due to their different substituents in their glycosyl groups. This gives a new insight into the development of therapeutic natural antioxidants against oxidative stress.

Dose-dependent pharmacokinetics of tyrosol galactoside as an anti-fatigue drug in rats.

Tyrosol galactoside (TG) is a new candidate anti-fatigue agent under development. In order to have a good understanding of its pharmacokinetic characters, the paper describes the dose-dependent pharmacokinetics of TG in rats after oral and intravenous administration. TG was rapidly absorbed after oral administration and cleared with first-order rate, for the plasma half-life was independent of dose. C(max) and AUC(0-infinity) after both intravenous and oral dosing were all linearly correlated with the dose, as the regression correlation coefficient (R) was 0.998, 0.989 and 0.994 for AUC(0-infinity) (i.v., P < 0.01) AUC(0-infinity) (i.g., P < 0.01) and C(max) (i. g., P < 0.01), respectively. However, these parameters increased less than proportionally with increasing dose. In addition, the apparent volume of distribution (Vd) and the apparent clearance (Cl) seemed to be affected by the dose.

Glycosylated nordihydroguaiaretic acids as anti-cancer agents.

Three perglycosylated nordihydroguaiaretic acids (NDGA) were synthesized through the Huiseng 1,3-dipolar cycloaddition reaction. These sugar-NDGA conjugates containing triazole-linkages possessed good solubility in water. NDGA-(triazol-galactose)(4) (12b) and NDGA-(triazol-glucose)(4) (12c) were found to act as inhibitors against human hepatocellular carcinoma Hep3B cells in culture.

Synthetic pseudopterosin analogues: A novel class of antiinflammatory drug candidates.

The synthesis and in vivo anti-inflammatory activity of a series of pseudopterosin analogues are presented. Synthetic tricyclic catechol aglycons with different substitution patterns were monofucosylated or -xylosylated. Anti-inflammatory activity was conserved over a wide range of structural modifications. The most active synthetic compound 33 reduced phorbol myristate acetate (PMA)-induced inflammation in the mouse ear by 72% at 50 µg/ear. This corresponds to 80% of the activity of natural pseudopterosin A.

Safety, pharmacokinetics and biodistribution studies of a beta-galactoside prodrug of doxorubicin for improvement of tumor selective chemotherapy.

Anthracycline antibiotics, particularly doxorubicin (DOX) and daunorubicin, have been used extensively in the treatment of human malignancies. However, cardiotoxicity and multidrug resistance are significant problems that limit the clinical efficacy of such agents. Rational design to avoid these side effects includes strategies such as drug targeting and prodrug synthesis. The DOX prodrug N-(beta-D-glucopyranosylbenzyloxycarbonyl)-doxorubicin (prodrug 1) was synthesized for specific activation by beta-galactosidase, which is expected to release in necrotic areas of tumor lesions. Described here is the safety, pharmacokinetics, and biodistribution studies of a beta-galactoside prodrug of DOX. In vivo safety evaluation was done in the Ehrlich Ascites Carcinoma (EAC) tumor model. The dose of DOX was 8 mg/kg and the dose of prodrug was 8 mg/kg and 24 mg/kg of DOX equivalents. Our results on cytotoxicity, which demonstrated compression in the number of EAC cells and their viability, substantiate these data. Prodrug 1 was safe up to a dose of 24 mg/kg of DOX equivalents in EAC mice. The pharmacokinetics and biodistribution of prodrug (300 mg/kg) in normal mice were determined and compared with DOX (20 mg/kg). Administration of DOX in normal mice resulted in a peak plasma concentration of 19.45 microM (t = 30 minutes). Prodrug injection resulted in 3- to 16-fold lower concentrations in the tissues of normal mice. As it is more polar, lower levels were observed in tissues and plasma in contrast to the parent compound DOX. In vivo safety studies have shown that prodrug 1 had a maximum tolerated dose compared with DOX and led to improved pharmacokinetics in normal mice.