Baseline sensitivity of HSV-1 and HSV-2 clinical isolates and defined acyclovir-resistant strains to the helicase–primase inhibitor pritelivir

Fifty-nine US isolates of HSV-1 and HSV-2 obtained between 1998 and 2004 were tested for sensitivity to the helicase–primase inhibitor, pritelivir (AIC316, BAY 57-1293) by plaque-reduction assay. All isolates, which were collected prior to any clinical use of primase–helicase inhibitors, were sensitive and showed mean EC₅₀ values of 0.026 and 0.029 μM for HSV-1 and HSV-2, respectively. Furthermore, several laboratory-selected acyclovir-resistant HSV mutants were also sensitive to pritelivir. These data provide a baseline for HSV sensitivity to pritelivir in general population before it is introduced and broadly used to treat HSV infection. The data also validate pritelivir as an appropriate therapy for nucleoside-resistant HSV infections.     

Inhibitory effect and structure–activity relationship of some Biginelli-type pyrimidines against HSV-1

Inevitable emergence of multi-drug resistant strains to current available drugs makes an impetus for finding new therapeutic agents against herpes simplex virus (HSV). In this study, a series of novel derivatives of Biginelli-type pyrimidines were evaluated as potential anti-HSV-1 compounds by plaque reduction method. The cellular toxicity was assessed by XTT proliferation assay. The time course of anti-HSV activity of the most active compound was studied to show the anti-viral effect in various intervals of replication cycle. Compounds 2, 6, 8, 11, 12, 17, 18, 20, and 40 had the highest activity for inhibition of HSV. Compound 40 inhibited HSV replication with IC₅₀ of 0.9 μmol/l and had CC₅₀ of up to 100 μmol/l. This compound was a noteworthy inhibitor against HSV with TI value of 111. Compound 20 also showed considerable inhibitory activity with IC₅₀ of 1.8 μmol/l. Result of time-of-addition study showed that compound 40 inhibits HSV replication at a stage after entry of virions to the target cells. Analysis of structure of the studied compounds demonstrated clear relationships with their anti-HSV effects. Some of the compounds seem to be promising candidates for future anti-HSV drug discovery researches. Structural manipulation based on the obtained structure–activity relationships would propose some new leads for anti-HSV drug discovery programs.     

Pomegranate pericarp extract enhances the antibacterial activity of ciprofloxacin against extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) producing Gram-negative bacilli

A methanolic extract of Punica granatum (pomegranate) fruit pericarp (PGME) was tested in combination with ciprofloxacin against extended-spectrum β-lactamase (ESBL) producing Escherichia coli, Klebsiella pneumoniae, and metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa, which were screened for their resistance profile against fluoroquinolone antibiotics. The minimum inhibitory concentrations (MIC) of ciprofloxacin and PGME, alone, were determined, and synergy of ciprofloxacin–PGME combinations evaluated by checkerboard assay and fractional inhibitory concentration (FIC). Nineteen out of forty-nine strains exhibited synergy with ciprofloxacin (FIC of 0.125–0.5 for ciprofloxacin) further verified by agar-well assay. This could be due to the bacterial efflux pump inhibitor (EPI) activity of the polyphenolic constituents of PGME. However, the isolates exhibiting a high level of ciprofloxacin resistance did not respond to ciprofloxacin–PGME combinations, which could be due to target site modification not influenced further by EPI activity of PGME. Again, some strains were sensitive or weakly resistant to ciprofloxacin, which exhibited ‘indifference’ to the combination, probably due to a lack of over-expressed efflux mechanism. Thus, a synergy of a ciprofloxacin–PGME combination was demonstrated for the first time against ESBL- and MBL-producing Gram-negative bacilli, and the efficacy of an existing drug improved with the help of an inexpensive alternative therapy.     

Antiviral and analgesic activity of the complex of Hypericum Perforatum L extract and Lysine monohydrochloride

Objective: To screen the antiviral and analgesic activities of the complex of extract of Hypericum Perforatum L (EHPL) and Lysine hydrochloride in mass ratio of 1: 1, 1: 2 and 2: 1 to determinewhich one is better. Methods: In screening test, the antiviral activities on herpes simplex virus type 1     

Anxiolytic-like effects of yohimbine in the murine plus-maze: strain independence and evidence against α2-adrenoceptor mediation

The influence of ₂-adrenoceptor antagonists in animal models of anxiety is quite inconsistent, with results spanning the full range of effect from anxiogenesis to anxiolysis. In the present study, an ethological technique was used to examine the effects of yohimbine (0.5–4.0 mg/kg) on plus-maze behaviour in DBA/2 mice. Results indicated significantanxiolytic-like effects on standard spatiotemporal measures at 2.0–4.0 mg/kg, and on risk assessment measures across the entire dose range. Full-scale follow-up studies with T1 and BALB/c strains confirmed that this action of yohimbine in the murine plus-maze is not peculiar to DBA/2 mice. The more selective ₂-adrenoceptor antagonist, idazoxan (0.63–5.0 mg/kg), exerted much weaker behavioural effects in the maze while the ₂-adrenoceptor agonist, clonidine (0.01–0.1 mg/kg), produced a profile consistent with non-specific behavioural disruption. Data are discussed in relation to the possible involvement of 5-HT_1A receptor mechanisms in the observed anxiolytic-like effects of yohimbine in the murine plus-maze.     

Protective effects of Ginkgo biloba extract against lysophosphatidylcholine-induced vascular endothelial cell damage

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Terpenoids of methanol extract of Clerodendrum infortunatum exhibit anticancer activity against Ehrlich’s ascites carcinoma (EAC) in mice

Context: Clerodendrum infortunatum Linn. is a widely used plant in the Indian indigenous system of medicine for the treatment of tumors.

Objective: The present study evaluated the anticancer activity of methanol extract of C. infortunatum (MECI) against Ehrlich’s ascites carcinoma (EAC) bearing Swiss albino mice and isolation of bioactive terpenoids from it.

Methods: HPLC analysis of the methanol extract showed the presence of three major components. Out of those, two compounds were isolated and characterized as oleanolic acid and clerodinin A. The anticancer activity of MECI was assessed by measuring the tumor growth response, percentage increase of life span, study of hematological parameters, lipid peroxidation, antioxidant enzyme activity like glutathion and CAT. In vitro cytotoxicity assay was also performed using EAC cell lines.

Result and conclusion: Treatment with MECI causes significant decrease in the tumor cell volume and increase in the life span. The median survival time (MST) of EAC control group was found as 19.42?±?0.91 d, whereas the MST was increased to 23.44?±?2.69 d and 27.57?±?2.57 d for the groups treated with MECI at 100 and 200?mg/kg, respectively. All the hematological parameters, malonaldehyde content and antioxidant enzymes’ activity were restored towards the normal level. IC₅₀ value of MECI was found as 498.33 µg/mL in cytotoxicity study. The experimental results suggested that MECI has significant anticancer activity, which can be attributed to the presence of oleanolic acid and clerodinin A.     

Structure–activity relationships and the cytotoxic effects of novel diterpenoid alkaloid derivatives against A549 human lung carcinoma cells

The cytotoxicity of three alkaloids from the roots of Aconitum yesoense var. macroyesoense as well as 36 semi-synthetic C₂₀-diterpenoid atisine-type alkaloid derivatives against A549 human lung carcinoma cells was examined. Ten acylated alkaloid derivatives, pseudokobusine 11-veratroate (9), 11-anisoate (12), 6,11-dianisoate (14), 11-p-nitrobenzoate (18), 11,15-di-p-nitrobenzoate (22), 11-cinnamate (25) and 11-m-trifluoromethylbenzoate (27), and kobusine 11-p-trifluoromethylbenzoate (35), 11-m-trifluoromethylbenzoate (36) and 11,15-di-p-nitrobenzoate (39), exhibited cytotoxic activity, and 11,15-dianisoylpseudokobusine (16) was found to be the most potent cytotoxic agent. Their IC₅₀ values against A549 cells ranged from 1.72 to 5.44 μM. In the occurrence of cytotoxic effects of atisine-type alkaloids, replacement by an acyl group at both C-11 and C-15 resulted in the enhancement of activity of the parent alkaloids compared to that from having hydroxy groups at this position, and the presence of a hydroxy group at the C-6 position was required for the cytotoxic effects. These acylated alkaloid derivatives inhibit cell growth through G1 arrest.     

“Aroeira” (Myracrodruon urundeuva) methanol extract: the relationship between chemical compounds and cellular effects

Context: “Aroeira” [Myracrodruon urundeuva Allemão (Anacardiaceae)] is a tree whose leaves have been studied for therapeutic purposes in medicine and dentistry.

Objective: The study chemically identifies the leaf extract of aroeira and determines its effect on human gingival fibroblasts.

Materials and methods: An 80% methanol leave extract was obtained by maceration and chemically identified through flow-injection analysis–electrospray ionization–ion trap–tandem mass spectrometry (FIA–ESI–IT–MSⁿ). Cytotoxicity of the aroeira’s methanol extract was evaluated in lineage of fibroblasts. Adherent cells were treated with different concentrations of aroeira’s methanol extract in the medium: 0.1, 1, 10, 100 and 1000?μg/mL. Control cells were cultivated in the medium only. Analyses were done at 24, 48, 72 and 96?h of culture by neutral red assay; and at 24, 48 and 96?h by crystal violet assay.

Results: FIA–ESI–IT–MS analysis determined the presence of compounds, for the first time in the species: quercetin-O-glucuronide and quercetin-O-deoxyhexose-O-glucose in the extract. On one hand, neutral red and crystal violet assay showed a reduction (to 50% up until 100%) of cellular viability of groups of 100 and 1000?μg/mL compared with control at 96?h (p?<?0.05). On the other hand, lower concentrations (0.1; 1 and 10?μg/mL) of the extract were similar to that of the control at 96?h (p?<?0.05), in general.

Conclusions: In view of the results, we can conclude that the extract of aroeira presents tannins and flavonoids. Furthermore, the extract is capable of modulating the viability of human gingival fibroblasts according to its concentration.     

Antiproliferative effects of novel urea derivatives against human prostate and lung cancer cells; and their inhibition of β-glucuronidase activity

Twenty-one novel urea derivatives were synthesized and their structures characterized by mass, NMR, IR, and UV spectroscopy. These compounds were evaluated for their antiproliferative profile against human PC-3 (prostate) and NCI-H460 (lung) cancer cell lines. Among them, compound 21 N-(3-nitrophenyl)-N′-(1-phenylethyl)urea was found to be active against both PC-3 (IC₅₀ ± SEM: 20.13 ± 0.91 μM) and NCI-H460 (GI₅₀: 22 ± 2.6 μM) cell lines; hence has the potential to be further studied as anticancer agent. These compounds were also investigated for their ability to inhibit urease, β-glucuronidase, and phosphodiesterase enzymes. N-(2,6-Dimethylphenyl)-N′-(4′-nitrophenyl)urea (1) demonstrated 90 % inhibition of β-glucuronidase enzyme (IC₅₀ ± SEM: 3.38 ± 0.043 μM).     

Demonstration of the “anti-stress” activity of an extract of Ginkgo biloba (EGb 761) using a discrimination learning task

1. Young (4-month-old) and old (20-month-old) rats, maintained under water restriction, were trained to discriminate to obtain a small amount of drinking water as a reward. Each animal had to learn to press a lever corresponding to a light that was randomly distributed on the left or right.2. Introduction of an auditory perturbation (“stress”) during the discriminative phase of learning modified the capacity and rate of acquisition in both young and old animals, changes that were correlated with increases in plasma concentrations of epinephrine, norepinephrine and corticosterone.3. Stress-induced detrimental changes in both discrimination learning and plasma hormones were suppressed by 20 days of oral treatment with an extract of Ginkgo biloba leaves (EGb 761; 50 or 100 mg/kg/day) in both young and old rats, effects that became statistically significant by the third day of learning (time of maximal acquisition rate).4. EGb 761 treatment was less effective in increasing the percentage of efficient lever presses in old than in young rats, but more effective in decreasing the number of inefficient lever presses and reaction time in the older animals.5. These results indicate that EGb 761 can facilitate behavioral adaptation despite adverse environmental influences, a property that supports its clinical use in treating cognitive impairment, especially in elderly patients.     

Protective effects of mecamylamine and atropine against α(4)β(2) nicotinic receptor expression and functional toxicity in paraoxon-treated rats

Chronic and acute exposure to organophosphate pesticides or related nerve agents may lead to persistent neurological and neurobehavioral effects, which cannot be explained by acetylcholinesterase (AChE) inhibition alone. In the present study, the effects of mecamylamine (2mg/kg), or atropine (10mg/kg) alone, or in combination, on the expression of nicotinic acetylcholine receptors (nAChRs) subunits, functional signs of toxicity and lethality in paraoxon-treated rats were investigated. Surviving animals were sacrificed after 48h of paraoxon administration. Paraoxon, at dosage of 1× LD50, significantly reduced expression of α(4) and β(2) nAChR subunits mRNA and protein in rat brain homogenates. Mecamylamine, efficiently prevented reduction of the α(4) and β(2) nAChR mRNA and protein in paraoxon exposed rat brains, but atropine was not efficient. Concurrent treatment with mecamylamine and atropine restored nAChRs mRNA and protein level and prevented lethality and severe involuntary movements induced by paraoxon. Nicotinic receptors antagonists may be included in the cocktail of therapeutic agents targeting the various mechanisms for neuronal injury by organophosphates.     

The effects of new sigma (σ) receptor ligands,PB190 and PB212, in the models predictive of antidepressant activity

BackgroundA number of σ receptor ligands have been demonstrated to possess antidepressant-like effect in some experimental paradigms (e.g. forced swim test, tail suspension test, olfactory bulbectomy model, conditioned fear stress). The objective of the present study was to find out whether PB190 and PB212, new σ₁ receptor ligands, show the effects in some models predictive of antidepressant activity.MethodsThe impact of PB190 and PB212 on the immobility time in the forced swim test (FST) and tail suspension test (TST) was assessed in C57BL/6J male mice. Extracellular bradykinin triggers a transient increase in intracellular calcium concentration by activating the phospholipase C/IP₃ pathway. The intracellular calcium concentration was estimated with the dual wavelength ratiometric probe Fura-2.ResultsIn the FST model, PB190 showed a moderate antidepressant-like effect (only in the dose of 3 mg/kg) which was enhanced by joint treatment with amantadine (AMA), 10 mg/kg (inactive per se). The decrease in the immobility time induced by the combined treatment with PB190 and AMA was counteracted by PB212 and by BD1047, a σ₁-receptor antagonist. The in vitro studies indicated that Ca²⁺-response was increased by 1 μM PB190, like by the σ₁-agonist (+)-pentazocine, while 1 μM PB212 behaved line σ₁-antagonist, BD1063. On the other hand, 100 μM PB190 negatively affected the Ca²⁺-response after bradykinin.ConclusionsThe obtained results: 1/indicated that in the in vivo conditions PB190 behaved as a σ₁-receptor agonist while PB212 counteracted its effect, confirming the in vitro data; 2/gave support to the hypothesis that σ₁-receptors might be one of possible mechanisms by which drugs induce antidepressant-like activity; 3/revealed that this effect may be potentiated by NMDA receptor antagonists, e.g. AMA.     

Hepatoprotective activity of berberine is mediated by inhibition of TNF-α, COX-2, and iNOS expression in CCl(4)-intoxicated mice

This study investigated the protective effects of isoquinoline alkaloid berberine on the CCl(4)-induced hepatotoxicity in mice. Berberine was administered as a single dose at 5 and 10mg/kg intraperitoneally (i.p.), 1h before CCl(4) (10%, v/v in olive oil, 2ml/kg) injection and mice were euthanized 24h later. The rise in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in CCl(4)-intoxicated mice was markedly suppressed by berberine in a concentration-dependent manner. The decrease in hepatic activity of superoxide dismutase (Cu/Zn SOD) and an increase in lipid peroxidation were significantly prevented by berberine. Histopathological changes were reduced and the expression of tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) was markedly attenuated by berberine 10mg/mg. The results of this study indicate that berberine could be effective in protecting the liver from acute CCl(4)-induced injury. The hepatoprotective mechanisms of berberine may be related to the free radical scavenging and attenuation of oxidative/nitrosative stress, as well as to the inhibition of inflammatory response in the liver.     

Antihyperglycaemic potential of the water–ethanol extract of Kalanchoe crenata (Crassulaceae)

Kalanchoe crenata is a vegetable widely used in Cameroon and largely efficient in the treatment of diabetes mellitus. The effect of the water–ethanol extract of this plant (WEKC) on blood glucose levels was investigated in fasting normal and diet-induced diabetic rats (MACAPOS 1) after a short- and medium-term treatment. Diabetes was induced by submitting Wistar rats to a hypercaloric sucrose diet over 4 months. Six hours after a single oral administration of WEKC, 135 and 200 mg kg⁻¹ body weight extracts significantly (P < 0.01) reduced the blood glucose levels both in normal and diabetic rats without real dose-dependant effect. During the medium-term treatment, 200 mg kg⁻¹ WEKC administered daily for 4 weeks significantly reduced blood glucose levels within week 1 (P < 0.05), with a maximum effect at week 4 (−52%, P < 0.01), while maintaining glycaemia within the normal range. All the WEKC-treated diabetic rats exhibited significant (P < 0.01) increase in insulin sensitivity index (K _ITT) compared with the initial time and to the untreated diabetic animals. Animals treated for 4 weeks exhibited a slight resistance in body-weight gain and decrease in food and water intake. The WEKC activities on all parameters assessed were comparable with the glibenclamide effects. Qualitative phytochemical screening revealed that K. crenata contains terpenoids, tannins, polysaccharids, saponins, flavonoids and alkaloids. The data suggest that K. crenata might contain important chemical components that could induce significant improvement in glucose clearance and/or uptake and resistance to body-weight gain and insulin sensitivity, and could be a potent alternative or complementary therapeutic substance in the control of type 2 diabetes and other insulin-resistant conditions.     

Multiple effects of putative α-adrenoceptor agonists on the electrical and mechanical activity of guinea-pig papillary muscle

Summary The effects of the putative -adrenoceptor agonists phenylephrine, methoxamine and clonidine on force of contraction and on calcium-dependent action potentials were studied in guinea-pig papillary muscles.Phenylephrine increased the force of contraction by stimulating -adrenoceptors as well as -adrenoceptors. It increased the amplitude and duration of slow action potentials, but this effect was exclusively due to stimulation of -adrenoceptors. The positive inotropic effect mediated by -adrenoceptors can presumably not be explained by an increase in calcium influx during the action potential via the slow inward current.Methoxamine had no effect on the force of contraction at 10^–5 and 10^–4 mol/l, but at 10^–4 mol/l it slightly decreased amplitude and duration of slow action potentials.Clonidine produced a large increase in force of contraction and in amplitude and duration of slow action potentials. These effects were due to stimulation of H₂-histamine receptors.It is concluded that in guinea-pig papillary muscle the tested putative -adrenoceptor agonists do not share a common -adrenoceptor effect, but produce prominent effects which are mediated through either -adrenoceptors (phenylcphrine), or H₂-histamine-receptors (clonidine) or are non-specific (methoxamine) in nature.     

Pharmacological interaction with the sigma1 (σ1)-receptor in the acute behavioral effects of antidepressants

Selective agonists of the sigma-1 (σ(1)) ligand-operated chaperone protein, like igmesine or PRE-084, are antidepressants in preclinical depression models. σ(1)-Protein activation may contribute to the antidepressant efficacy of drugs known to act as selective serotonin-reuptake inhibitors (SSRI) or noradrenaline reuptake inhibitors through direct or indirect involvement of the σ(1)-receptor in the drug effect. We here compared antidepressant effects in two behavioral procedures, the forced swimming test (FST) and conditioned fear stress (CFS). The involvement of the σ(1)-receptor was examined using a co-treatment with the σ(1)-antagonist BD1047 or using σ(1)-knockout (KO) mice. Igmesine but not PRE-084 decreased FST immobility. The SSRI fluoxetine and sertraline, but not fluvoxamine, and the tricyclic antidepressants imipramine, desipramine, and amitriptyline were also effective. Only the effect of igmesine was blocked by BD1047 or in σ(1)-KO mice. Igmesine, PRE-084, fluvoxamine, and sertraline decreased the CFS immobility in a BD1047- and σ(1)-KO-sensitive manner. Among tricyclics, only amitriptyline was effective and its effect was unaffected by BD1047 or in σ(1)-KO mice. The behavioral effects induced by mixed σ(1)-receptor/SSRI antidepressants, like fluvoxamine or sertraline, may therefore involve a non-selective action at both targets. Moreover, the CFS appears to more reliably uncover a σ(1) pharmacological component in antidepressant screening.     

Insecticidal activity and structure–activity relationship of sugar embedded macrocycles for the control of aphid (Aphis craccivora Koch)

Abstract

Toxicity of sugar embedded macrocycles was evaluated for their toxicity against nymphs of aphid, Aphis craccivora Koch (Hemiptera: Aphididae) in the laboratory conditions. Most of the compounds showed toxicity to A. craccivora. However, the activity of different macrocycles varied depending on the nature and position of various functional groups possess by these compounds. Results revealed that among them, compound 3c found more effective for the control of A. craccivora (LC₅₀?=?413?mg?L^–1) and was followed by 3b (LC₅₀?=?442.62?mg?L^?1) and 3e (LC₅₀?=?480.19?mg?L^?1).     

Mixed antagonistic effects of the ginkgolides at recombinant human ρ(1) GABA(C) receptors

The diterpene lactones of Ginkgo biloba, ginkgolides A, B and C are antagonists at a range of Cys-loop receptors. This study examined the effects of the ginkgolides at recombinant human ρ₁ GABA_C receptors expressed in Xenopus oocytes using two-electrode voltage clamp. The ginkgolides were moderately potent antagonists with IC₅₀s in the μM range. At 10 μM, 30 μM and 100 μM, the ginkgolides caused rightward shifts of GABA dose–response curves and reduced maximal GABA responses, characteristic of noncompetitive antagonists, while the potencies showed a clear dependence on GABA concentration, indicating apparent competitive antagonism. This suggests that the ginkgolides exert a mixed-type antagonism at the ρ₁ GABA_C receptors. The ginkgolides did not exhibit any obvious use-dependent inhibition. Fitting of the data to a number of kinetic schemes suggests an allosteric inhibition as a possible mechanism of action of the ginkgolides which accounts for their inhibition of the responses without channel block or use-dependent inhibition. Kinetic modelling predicts that the ginkgolides exhibit saturation of antagonism at high concentrations of GABA, but this was only partially observed for ginkgolide B. It also suggests that there may be different binding sites in the closed and open states of the receptor, with a higher affinity for the receptor in the closed state.