Synergistic Inhibition of HIV-1 in Activated and Resting Peripheral Blood Mononuclear Cells, Monocyte-Derived Macrophages, and Selected Drug-Resistant Isolates With Nucleoside Analogues Combined With a Natural Product, Resveratrol:

Forecasting burden of long-term disability from neonatal conditions: results from the Projahnmo I trial, Sylhet, Bangladesh

INTRODUCTION

The burden of disease resulting from neonatal conditions is substantial in developing countries. From 2003 to 2005, the Projahnmo I programme delivered community-based interventions for maternal and newborn health in Sylhet, Bangladesh. This analysis quantifies burden of disability and incorporates non-fatal outcomes into cost-effectiveness analysis of interventions delivered in the Projahnmo I programme.

METHODS

A decision tree model was created to predict disability resulting from preterm birth, neonatal meningitis and intrapartum-related hypoxia ('birth asphyxia'). Outcomes were defined as the years lost to disability (YLD) component of disability-adjusted life years (DALYs). Calculations were based on data from the Projahnmo I trial, supplemented with values from published literature and expert opinion where data were absent.

RESULTS

195 YLD per 1000 neonates [95% confidence interval (CI): 157-241] were predicted in the main calculation, sensitive to different DALY assumptions, disability weights and alternative model structures. The Projahnmo I home care intervention may have averted 2.0 (1.3-2.8) YLD per 1000 neonates. Compared with calculations based on reductions in mortality alone, the cost-effectiveness ratio decreased by only 0.6% from $105.23 to $104.62 ($65.15-$266.60) when YLD were included, with 0.6% more DALYs averted [total 338/1000 (95% CI: 131-542)].

DISCUSSION

A significant burden of disability results from neonatal conditions in Sylhet, Bangladesh. Adding YLD has very little impact on recommendations based on cost-effectiveness, even at the margin of programme adoption. This model provides guidance for collecting data on disabilities in new settings.

An optimum fermentation model established by genetic algorithm for biotransformation from crude polydatin to resveratrol

Natural resveratrol is widely used in medicine, food, and cosmetic because of its pharmacological properties. Due to its low content in plants, this study was conducted to increase the yield of resveratrol by microorganism transformation. Fungi Aspergillus niger AN-2436 was employed in biotransformation to produce resveratrol from polydatin, and genetic algorithm (GA) was used to optimize the fermentation conditions. A transformation ratio of higher than 95% was achieved in the following conditions: culture temperature of 30.3 °C, inoculum size of 20% (v/v), rotating speed of 147 rpm, and cultivation time of 36 h. Compared with the polydatin absorbance under the experimental conditions obtained by single-factor, orthogonal experiments and average absorbance, the GA provides the optimum experimental conditions, under which the largest transformation rate was achieved. The final transformation product obtained was identified as resveratrol, and it was proved by high-performance liquid chromatography, infrared, mass spectrometry, and nuclear magnetic resonance.

Comparative inhibitory activity of the stilbenes resveratrol and oxyresveratrol on African swine fever virus replication

Stilbenols are polyphenolic phytoalexins produced by plants in response to biotic or abiotic stress. These compounds have received much attention because of their significant biological effects. One of these is their antiviral action, which has previously been documented for two members of this class, namely resveratrol and oxyresveratrol. Here we tested the antiviral effect of these two compounds on African swine fever virus, the only member of the newly created family Asfarviridae and a serious limitation to porcine production worldwide. Our results show a potent, dose-dependent antiviral effect of resveratrol and oxyresveratrol in vitro. Interestingly, this antiviral activity was found for these synthetic compounds and also for oxyresveratrol extracted from new natural sources (mulberry twigs). The antiviral effect of these two drugs was demonstrated at concentrations that do not induce cytotoxicity in cultured cells. Moreover, these antivirals achieved a 98-100% reduction in viral titers. Both compounds allowed early protein synthesis but inhibited viral DNA replication, late viral protein synthesis and viral factory formation.

Early inhibitors of human cytomegalovirus: state-of-art and therapeutic perspectives

Human cytomegalovirus (HCMV) infection is associated with severe morbidity and mortality in immunocompromised individuals, mainly transplant recipients and AIDS patients, and is the most frequent cause of congenital malformations in newborn children. To date, few drugs are licensed for the treatment of HCMV infections, most of which target the viral DNA polymerase and suffer from many drawbacks, including long-term toxicity, low potency, and poor bioavailability. In addition, the emergence of drug-resistant viral strains is becoming an increasing problem for disease management. Finally, none of the current anti-HCMV drugs have been approved for the treatment of congenital infections. For all these reasons, there is still a strong need for new anti-HCMV drugs with novel mechanisms of action. The first events of the virus replication cycle, including attachment, entry, immediate-early gene expression, and immediate-early functions—in particular that of Immediate-Early 2 protein—represent attractive targets for the development of novel antiviral compounds. Such inhibitors would block not only the expression of viral immediate-early proteins, which play a key role in the pathogenesis of HCMV infection, but also the host immunomodulation and the changes to cell physiology induced by the first events of virus infection. This review describes the current knowledge on the initial phases of HCMV replication, their validation as potential novel antiviral targets, and the development of compounds that block such processes.

Inhibition of influenza virus replication by plant-derived isoquercetin

Influenza virus infects the respiratory system of human and animals causing mild to severe illness which could lead to death. Although vaccines are available, there is still a great need for influenza antiviral drugs to reduce disease progression and virus transmission. Currently two classes (M2 channel blockers and neuraminidase inhibitors) of FDA-approved influenza antiviral drugs are available, but there are great concerns of emergence of viral resistance. Therefore, timely development of new antiviral drugs against influenza viruses is crucial. Plant-derived polyphenols have been studied for antioxidant activity, anti-carcinogenic, and cardio- and neuroprotective actions. Recently, some polyphenols, such as resveratrol and epigallocatechin gallate, showed significant anti-influenza activity in vitro and/or in vivo. Therefore we investigated selected polyphenols for their antiviral activity against influenza A and B viruses. Among the polyphenols we tested, isoquercetin inhibited the replication of both influenza A and B viruses at the lowest effective concentration. In a double treatment of isoquercetin and amantadine, synergistic effects were observed on the reduction of viral replication in vitro. The serial passages of virus in the presence of isoquercetin did not lead to the emergence of resistant virus, and the addition of isoquercetin to amantadine or oseltamivir treatment suppressed the emergence of amantadine- or oseltamivir-resistant virus. In a mouse model of influenza virus infection, isoquercetin administered intraperitoneally to mice inoculated with human influenza A virus significantly decreased the virus titers and pathological changes in the lung. Our results suggest that isoquercetin may have the potential to be developed as a therapeutic agent for the treatment of influenza virus infection and for the suppression of resistance in combination therapy with existing drugs.

Resveratrol: its biologic targets and functional activity

The polyphenolic phytoalexin resveratrol (RSV) and its analogues have received tremendous attention over the past couple of decades because of a number of reports highlighting their benefits in vitro and in vivo in a variety of human disease models, including cardio- and neuroprotection, immune regulation, and cancer chemoprevention. These studies have underscored the high degree of diversity in terms of the signaling networks and cellular effector mechanisms that are affected by RSV. The activity of RSV has been linked to cell-surface receptors, membrane signaling pathways, intracellular signal-transduction machinery, nuclear receptors, gene transcription, and metabolic pathways. The promise shown by RSV has prompted heightened interest in studies aimed at translating these observations to clinical settings. In this review, we present a comprehensive account of the basic chemistry of RSV, its bioavailability, and its multiple intracellular target proteins and signaling pathways.

Biological and medicinal properties of grapes and their bioactive constituents: an update

The grape is one of the most valued conventional fruits, worldwide. Although most of the parts of the grapevine are useful, primarily, the grape is considered as a source of unique natural products not only for the development of valuable medicines against a number of diseases, but also for manufacturing various industrial products. Over the last few decades, apart from the chemistry of grape compounds, considerable progress has been made towards exploring the biological activities of various grape-derived constituents. Today, it is well established that in addition to serving as food, the grape is a major source of several phytochemicals. The main biologically active and well-characterized constituent from the grape is resveratrol, which is known for various medicinal properties in human diseases. This review discusses the roles of various grape-derived phytochemicals in relation to various diseases.

Resveratrol inhibition of varicella-zoster virus replication in vitro

Resveratrol was found to inhibit varicella-zoster virus (VZV) replication in a dose-dependent and reversible manner. This decrease in virus production in the presence of resveratrol was not caused by direct inactivation of VZV or inhibition of virus attachment to MRC-5 cells. The drug effectively limited VZV replication if added during the first 30 h of infection. Western blot analysis and real-time RT-PCR studies demonstrated that protein and mRNA levels of IE62, an essential immediate early viral protein, were reduced when compared to controls. These results demonstrate that VZV replication is adversely affected by resveratrol which is negatively impacting IE62 synthesis.

Host cell targets for antiviral therapy: an update

The discovery of antiviral therpeutic targets has traditionally focussed on conserved viral gene products. Since viruses are obligate molecular parasites requiring and manipulating host cell functions, the identification of host proteins essential to viruses but not cellular survival represent attractive and underutilized targets for antiviral therapies. Numerous studies have identified host cell functions, pathways and proteins that are essential for viral propagation, from entry to replication, assembly and egress. Importantly, several studies demonstrate virus inhibition through nonlethal impairment of host cell function both in vitro and in vivo. In addition, high-throughput experimental platforms allowing global or near-global surveillance of host gene products in the context of virus replication are now being used to systematically identify host cell targets. Recent breakthrough studies that have employed such methods successfully to identify host proteins and pathways crucial for virus growth are discussed in this review.

3,4',5-Trihydroxy-trans-stilbene (resveratrol) inhibits human cytomegalovirus replication and virus-induced cellular signaling

Resveratrol is a polyphenolic natural product that is present in red wine and peanuts and has inhibitory activity against inflammation, heart disease, and cancer. Here we describe its inhibition of human cytomegalovirus replication (IC50 = 1-2 microM). At least 50-fold higher concentrations of compound were required to produce cytotoxicity against growing or stationary human embryonic lung fibroblasts. Mechanism of action studies determined that resveratrol blocked virus-induced activation of the epidermal growth factor receptor (EGFR) and phosphatidylinositol-3-kinase signal transduction as well as NF-kappaB and Sp1 transcription factor activation shortly following infection. Resveratrol prevented the appearance of immediate-early, early, and late viral proteins. Human cytomegalovirus DNA replication was reduced to undetectable levels by treatment with resveratrol, as were the second (late) phases of virus-induced phosphatidylinositol-3-kinase signaling and transcription factor activation. Resveratrol lost substantial antiviral activity when its addition was delayed until 4 h postinfection. Compound reversibility and preincubation studies were inconsistent with a virucidal mechanism of action. These data indicated that this compound likely operated during attachment and entry. We hypothesize that the primary molecular target for resveratrol may be blockage of epidermal growth factor receptor activation and its downstream effectors.

Potential utility of natural polyphenols for reversing fat-induced insulin resistance

There is intriguing recent evidence that the beta subunit of the signalsome--IKKbeta, a crucial catalyst of NF-kappaB activation--is an obligate mediator of the disruption of insulin signaling induced by excessive exposure of tissues to free fatty acids and by hypertrophy of adipocytes. Thus, agents which safely inhibit or suppress the activation of IKKbeta may have utility for reversing insulin resistance syndrome and aiding control of type 2 diabetes. Two natural agents which can achieve this effect in vitro--and which may have clinical potential in this regard--are the polyphenols resveratrol and silibinin. To date, limited absorbability and/or rapid glucuronidation have prevented these agents from achieving full therapeutic utility, but, by administering these agents in optimally absorbable forms, and co-administering inhibitors of glucuronidation such as probenecid, it may prove feasible to make these agents more clinically viable. Oral silibinin, in the guise of the milk thistle extract silymarin, already has documented clinical utility in a range of hepatic disorders, and recent evidence that dietary silibinin can inhibit the growth of certain cancers in rodents suggests that this agent may indeed have clinical potential as an IKKbeta inhibitor. A report that silymarin has a favorable impact on glycemic and lipidemic control in type 2 diabetics with cirrhosis, may or may not be indicative of IKKbeta inhibition in skeletal muscle and adipocytes. In light of the fact that IKKbeta plays a crucial role, not only in the induction of insulin resistance, but also atherogenesis, a host of inflammatory disorders, and the survival and spread of cancer, the development of pharmaceutical agents that could safely and feasibly achieve a down-regulation of IKKbeta activity would have broad therapeutic and preventive implications.