Antibacterial and antiviral evaluation of sulfonoquinovosyldiacylglyceride: a glycolipid isolated from Azadirachta indica leaves

Aescin Inhibits Herpes simplex Virus Type 1 Induced Membrane Fusion

Infections with Herpes simplex virus can cause severe ocular diseases and encephalitis. The present study aimed to investigate potential inhibitors of fusion between HSV-1 and the cellular membrane of the host cell. Fusion and entry of HSV-1 into the host cell is mimicked by a virus-free eukaryotic cell culture system by co-expression of the HSV-1 glycoproteins gD, gH, gL, and gB in presence of a gD receptor, resulting in excessive membrane fusion and polykaryocyte formation. A microscopic read-out was used for the screening of potential inhibitors, whereas luminometric quantification of cell-cell fusion was used in a reporter fusion assay. HSV-1 gB was tagged at its C-terminus with mCherry to express mCherry-gB in both assay systems for the visualization of the polykaryocyte formation. Reporter protein expression of SEAP was regulated by a Tet-On 3 G system. The saponin mixture aescin was identified as the specific inhibitor (IC50 7.4 µM, CC50 24.3 µM, SI 3.3) of membrane fusion. A plaque reduction assay on Vero cells reduced HSV-1 entry into cells and HSV-1 cell-to-cell spread significantly; 15 µM aescin decreased relative plaque counts to 41%, and 10 µM aescin resulted in a residual plaque size of 11% (HSV-1 17 syn+) and 2% (HSV-1 ANG path). Release of the HSV-1 progeny virus was reduced by one log step in the presence of 15 µM aescin. Virus particle integrity was mainly unaffected. Analytical investigation of aescin by UHPLC-MS revealed aescin IA and -IB and isoaescin IA and -IB as the main compounds with different functional activities. Aescin IA had the lowest IC50, the highest CC50, and an SI of > 4.6.

Plant and algal lipidomes: Analysis, composition, and their societal significance

Plants and algae play a crucial role in the earth's ecosystems. Through photosynthesis they convert light energy into chemical energy, capture CO2 and produce oxygen and energy-rich organic compounds. Photosynthetic organisms are primary producers and synthesize the essential omega 3 and omega 6 fatty acids. They have also unique and highly diverse complex lipids, such as glycolipids, phospholipids, triglycerides, sphingolipids and phytosterols, with nutritional and health benefits. Plant and algal lipids are useful in food, feed, nutraceutical, cosmeceutical and pharmaceutical industries but also for green chemistry and bioenergy. The analysis of plant and algal lipidomes represents a significant challenge due to the intricate and diverse nature of their composition, as well as their plasticity under changing environmental conditions. Optimization of analytical tools is crucial for an in-depth exploration of the lipidome of plants and algae. This review highlights how lipidomics analytical tools can be used to establish a complete mapping of plant and algal lipidomes. Acquiring this knowledge will pave the way for the use of plants and algae as sources of tailored lipids for both industrial and environmental applications. This aligns with the main challenges for society, upholding the natural resources of our planet and respecting their limits.

Unveiling the Neem (Azadirachta indica) Effects on Biofilm Formation of Food-Borne Bacteria and the Potential Mechanism Using a Molecular Docking Approach

Biofilms currently represent the most prevalent bacterial lifestyle, enabling them to resist environmental stress and antibacterial drugs. Natural antibacterial agents could be a safe solution for controlling bacterial biofilms in food industries without affecting human health and environmental safety. A methanolic extract of Azadirachta indica (neem) leaves was prepared and analyzed using gas chromatography-mass spectrometry for the identification of its phytochemical constituents. Four food-borne bacterial pathogens (Bacillus cereus, Novosphingobium aromaticivorans, Klebsiella pneumoniae, and Serratia marcescens) were tested for biofilm formation qualitatively and quantitatively. The antibacterial and antibiofilm properties of the extract were estimated using liquid cultures and a microtiter plate assay. The biofilm inhibition mechanisms were investigated using a light microscope and molecular docking technique. The methanolic extract contained 45 identified compounds, including fatty acids, ester, phenols, flavonoids, terpenes, steroids, and antioxidants with antimicrobial, anticancer, and anti-inflammatory properties. Substantial antibacterial activity in relation to the extract was recorded, especially at 100 μg/mL against K. pneumoniae and S. marcescens. The extract inhibited biofilm formation at 100 μg/mL by 83.83% (S. marcescens), 73.12% (K. pneumoniae), and 54.4% (N. aromaticivorans). The results indicate efficient biofilm formation by the Gram-negative bacteria S. marcescens, K. pneumoniae, and N. aromaticivorans, giving 0.74, 0.292, and 0.219 OD at 595 nm, respectively, while B. cereus was found to have a low biofilm formation potential, i.e., 0.14 OD at 595 nm. The light microscope technique shows the antibiofilm activities with the biofilm almost disappearing at 75 μg/mL and 100 μg/mL concentrations. This antibiofilm property was attributed to DNA gyrase inhibition as illustrated by the molecular docking approach.

Antibacterial Effect of Euryale ferox Seed Shell Polyphenol Extract on Salmonella Typhimurium

This study aimed to evaluate the effects of Euryale ferox Seed Shell Polyphenol Extract (EFSSPE) on a foodborne pathogenic bacterium. EFSSPE showed antimicrobial activity toward Salmonella Typhimurium CICC 22956; the minimum inhibitory concentration of EFSSPE was 1.25 mg/mL, the inhibition curve also reflected the inhibitory effect of EFSSPE on the growth of S. Typhimurium. Detection of alkaline phosphatase outside the cell revealed that EFSSPE treatment damaged the cell wall integrity of S. Typhimurium. EFSSPE also altered the membrane integrity, thereby causing leaching of 260-nm-absorbing material (bacterial proteins and DNA). Moreover, the activities of succinate dehydrogenase and malate dehydrogenase were inhibited by EFSSPE. The hydrophobicity and clustering ability of cells were affected by EFSSPE. Scanning electron microscopy showed that EFSSPE treatment damaged the morphology of the tested bacteria. These results indicate that EFSSPE can destroy the cell wall integrity and alter the permeability of the cell membrane of S. Typhimurium.

Synergistic Inhibitions of Gram-Negative Bacteria by Combination Treatment with Ciprofloxacin and a Novel Glucolipid

Psychrophilic fungus Pseudogymnoascus sp. OUCMDZ-4032 derived from Antarctica was cultivated under 16 °C to produce a new glucolipid compound (1). Its structure was elucidated by analysis of detailed spectroscopic data, acid hydrolysis and 1-phenyl-3-methyl-5-pyrazolone precolumn derivatization, and 13C NMR quantum chemical calculations. Though compound 1 did not show inhibitory activity against bacteria, it can reduce the minimum inhibitory concentration (MIC) of ciprofloxacin against Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli, and Salmonella paratyphi by 1024, 256 and 256-fold. Compound 1 showed potential as a synergistically inhibiting adjuvant in co-administration with antibiotic to enhance antibacterial activities.

The Physicochemical and Functional Properties of Biosurfactants: A Review

Surfactants, also known as surface-active agents, have emerged as an important class of compounds with a wide range of applications. However, the use of chemical-derived surfactants must be restricted due to their potential adverse impact on the ecosystem and the health of human and other living organisms. In the past few years, there has been a growing inclination towards natural-derived alternatives, particularly microbial surfactants, as substitutes for synthetic or chemical-based counterparts. Microbial biosurfactants are abundantly found in bacterial species, predominantly Bacillus spp. and Pseudomonas spp. The chemical structures of biosurfactants involve the complexation of lipids with carbohydrates (glycolipoproteins and glycolipids), peptides (lipopeptides), and phosphates (phospholipids). Lipopeptides, in particular, have been the subject of extensive research due to their versatile properties, including emulsifying, antimicrobial, anticancer, and anti-inflammatory properties. This review provides an update on research progress in the classification of surfactants. Furthermore, it explores various bacterial biosurfactants and their functionalities, along with their advantages over synthetic surfactants. Finally, the potential applications of these biosurfactants in many industries and insights into future research directions are discussed.

Prospects on Tuning Bioactive and Antimicrobial Denture Base Resin Materials: A Narrative Review

Denture base resin (DBR) materials are used in dentistry in constructing removable dentures and implant-supported prostheses. A plethora of evidence has demonstrated that DBR materials are associated with a high risk of denture stomatitis, a clinical complication where the soft oral tissues underneath the resin-based material are inflamed. The prevalence of denture stomatitis among denture wearers is high worldwide. Plaque accumulation and the infiltration of oral microbes into DBRs are among the main risk factors for denture stomatitis. The attachment of fungal species, mainly Candida albicans, to DBRs can irritate the underneath soft tissues, leading to the onset of the disease. As a result, several attempts were achieved to functionalize antimicrobial compounds and particles into DBRs to prevent microbial attachment. This review article explored the advanced approaches in designing bioactive and antimicrobial DBR materials. It was reported that using monomer mixtures, quaternary ammonium compounds (QACs), and organic and inorganic particles can suppress the growth of denture stomatitis-related pathogens. This paper also highlighted the importance of characterizing bioactive DBRs to be mechanically and physically sustainable. Future directions may implement a clinical translational model to attempt these materials inside the oral cavity.

The Antimicrobial Potential of the Neem Tree Azadirachta indica

Azadirachta indica (A. Juss), also known as the neem tree, has been used for millennia as a traditional remedy for a multitude of human ailments. Also recognized around the world as a broad-spectrum pesticide and fertilizer, neem has applications in agriculture and beyond. Currently, the extensive antimicrobial activities of A. indica are being explored through research in the fields of dentistry, food safety, bacteriology, mycology, virology, and parasitology. Herein, some of the most recent studies that demonstrate the potential of neem as a previously untapped source of novel therapeutics are summarized as they relate to the aforementioned research topics. Additionally, the capacity of neem extracts and compounds to act against drug-resistant and biofilm-forming organisms, both of which represent large groups of pathogens for which there are limited treatment options, are highlighted. Updated information on the phytochemistry and safety of neem-derived products are discussed as well. Although there is a growing body of exciting evidence that supports the use of A. indica as an antimicrobial, additional studies are clearly needed to determine the specific mechanisms of action, clinical efficacy, and in vivo safety of neem as a treatment for human pathogens of interest. Moreover, the various ongoing studies and the diverse properties of neem discussed herein may serve as a guide for the discovery of new antimicrobials that may exist in other herbal panaceas across the globe.

Ayurvedic Medicinal Plants Against COVID-19: An In Silico Analysis

Even after one and a half years since the outbreak of COVID-19, its complete and effective control is still far from being achieved despite vaccination drives, symptomatic management with available drugs, and wider lockdowns. This has inspired researchers to screen potential phytochemicals from medicinal plants against SARS-CoV-2, adopting a bio-informatics approach. The current study aimed to assess anti-viral activity of the phytochemicals derived from Ayurvedic medicinal plants against SARS-CoV-2 drug targets [3-chymotrypsin-like protease (3CLpro) and RNA dependent RNA polymerase (RdRp)] using validated in silico methods.3D Structures of 196 phytochemicals from three Ayurvedic plants were retrieved from PubChem and KNApSAcK databases and screened for Absorption Distribution Metabolism Excretion and Toxicity(ADMET) to predict drug-likeness. The phytochemicals were subjected to molecular docking and only three showed promise: Acetovanillonewith a binding affinity of −4.7Kcal/mol with RdRp and −4.1 Kcal/mol with 3CL pro; myrtenol with equivalent values of −4.3 Kcal/mol with RdRP and −3.2 Kcal/mol with 3CLpro; and nimbochalcin with equivalent values of −5.0Kcal/mol with RdRp and −4.9 Kcal/mol with 3CLpro. Molecular dynamics simulation (50ns) analysis was made of 3CLpro and RdRp using Autodock Vina 1.1.2 software and VMD software. After ADMET analysis, 78 phytochemicals were found suitable for molecular docking. Three, namely acetovanillone, myrtenol and nimbochalcin from Picrorhiza kurroa, Azadirachta indica and Cyperus rotundus,respectively,exhibited good binding affinity with 3CLproand RdRp of SARS-CoV-2. Interaction analysis, molecular dynamics simulations and MM-PBSA calculations were executed for two complexes, acetovanillone_RdRp and myrtenol_3CL pro.Acetovanillone_RdRpcomplex did not display any structural change after MD simulation as compared to myrtenol_3CL pro. The overall stability of acetovanillone_6NUR was 154.7 kJ/mol, and for myrtenol_1UJ1 90.5 kJ/mol. In silico analysis revealed that acetovanillone ( Picrorhiza kurroa) and myrtenol ( Cyperus rotundus) possess anti SARS-CoV-2 activity. Further studies are needed to validate their efficacy in biological models.

Investigation on the surface-active and antimicrobial properties of a natural glycolipid product

Glycolipids are a group of sugar-containing lipids with versatile functions. In this study, a natural glycolipid product was obtained from soy lecithin, and its emulsifying, oil-gelling, antibacterial and antiviral properties were investigated. A silica-based extraction method on a preparative scale was used to recover the glycolipid product (GLP) from soy lecithin. The GLP consisted of three different glycolipid classes: acylated sterol glucoside (64.16%), sterol glucoside (25.57%) and cerebroside (6.71%). As an emulsifier, the GLP was able to form a stable water-in-oil emulsion. The GLP exhibited a good oil-gelling property, capable of gelling rapeseed oil at a concentration of 6%. For the investigated microorganisms (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus), the GLP did not show any antibacterial effects. The GLP exerted antiviral activity against lentivirus, but not adenovirus. The results of this study help in enriching the knowledge on the properties of naturally occurring glycolipids, which may find potential applications in the food, pharmaceutical and related industries.

Aqueous Azadirachta indica (Neem) Extract Attenuates Insulin Resistance to Improve Glycemic Control and Endothelial Function in Subjects with Metabolic Syndrome

Neem (Azadirachta indica) exhibits multiple therapeutic benefits in preclinical studies, but clinical studies are lacking. This clinical study investigated the efficacy and safety of an aqueous A. indica leaf and twig extract (NEEM) on metabolic parameters in subjects with metabolic syndrome (MetS). Subjects were randomized to receive (1) placebo or (2) 125 mg, (3) 250 mg, or (4) 500 mg of NEEM twice daily (n = 20/group) for 12 weeks. Fasting blood sugar (FBS) and insulin, postprandial blood sugar (PPBS), insulin resistance (IR), hemoglobin A1c (HbA1c), endothelial function, circulating markers of inflammation and oxidative stress, lipid profiles, and platelet aggregation were measured at weeks 0, 4, 8, and 12. NEEM supplementation dose dependently improved the trajectories for FBS, PPBS, IR, and HbA1c over time, as well as endothelial function and most markers of inflammation and oxidative stress. Therefore, NEEM may be considered a promising therapeutic to attenuate the hyperglycemia and associated cardiometabolic derangements in people with MetS. Clinical trial registration no.: CTRI/2019/03/018034 [registered on: March 12, 2019].

Extract of neem (Azadirachta indica) leaf exhibits bactericidal effect against multidrug resistant pathogenic bacteria of poultry

The aim of the study was to determine the efficacy of neem leaf extract against multidrug resistant (MDR) pathogenic bacteria. Laboratory stock culture of Pasteurella multocida, Salmonella pullorum, Salmonella gallinarum and Escherichia coli was revived. Antibiogram profiles of these bacteria were determined by disc diffusion method. Ethanolic extract of neem leaf was prepared. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of neem leaf extract (112.5, 100, 50, 25, 12.5, 6.25 and 3.12 mg/ml) against MDR pathogenic bacteria of poultry were determined by double dilution method. The MIC and MBC of the neem leaf extract were 12.5 and 25 mg/ml, respectively for P. multocida, 50 and 100 mg/ml for S. pullorum and S. gallinarum, 100 and 112.5 mg/ml for E. coli. Neem leaf extracts exhibited bactericidal effect against MDR pathogenic bacteria of poultry.

An extract of Stephania hernandifolia, an ethnomedicinal plant, inhibits herpes simplex virus 1 entry

Stephania hernandifolia (Nimukho), an ethnomedicinal herb from rural Bengal, has been used traditionally for the management of nerve, skin, urinary, and digestive ailments. Here, we attempted to confirm the antiviral potential of aqueous, methanol, and chloroform extracts of S. hernandifolia against herpes simplex virus type 1 (HSV-1), the causative agent of orolabial herpes in humans, and decipher its underlying mechanism of action. The bioactive extract was standardized and characterized by gas chromatography-mass spectroscopy, while cytotoxicity and antiviral activity were evaluated by MTT and plaque reduction assay, respectively. Two HSV strains, HSV-1F and the clinical isolate VU-09, were inhibited by the chloroform extract (CE) with a median effective concentration (EC₅₀) of 4.32 and 4.50 µg/ml respectively, with a selectivity index (SI) of 11. Time-of-addition assays showed that pre-treatment of virus-infected cells with the CE and its removal before infection reduced the number of plaques without lasting toxicity to the cell, indicating that the CE affected the early stage in the viral life cycle. The number of plaques was also reduced by direct inactivation of virions and by the addition of CE for a short time following attachment of virions. These results together suggest that modification of either the virion surface or the cell surface by the CE inhibits virus entry into the host cell.

Natural Compounds as Therapeutic Agents: The Case of Human Topoisomerase IB

Natural products are widely used as source for drugs development. An interesting example is represented by natural drugs developed against human topoisomerase IB, a ubiquitous enzyme involved in many cellular processes where several topological problems occur due the formation of supercoiled DNA. Human topoisomerase IB, involved in the solution of such problems relaxing the DNA cleaving and religating a single DNA strand, represents an important target in anticancer therapy. Several natural compounds inhibiting or poisoning this enzyme are under investigation as possible new drugs. This review summarizes the natural products that target human topoisomerase IB that may be used as the lead compounds to develop new anticancer drugs. Moreover, the natural compounds and their derivatives that are in clinical trial are also commented on.

Punicalagin Damages the Membrane of Salmonella Typhimurium

Salmonella, a bacterial foodborne pathogen, can contaminate meat, milk, and vegetables. While appropriate measures are available to control Salmonella, the inhibitory phytochemicals from plants are gaining increased attention. Punicalagin, a natural antimicrobial, is one of the main active tannins isolated from Punica granatum L. To obtain a broader understanding of the effect of punicalagin on the cell membranes of Salmonella Typhimurium, the growth curves, extracellular potassium concentration, release of cell constituents, intracellular pH, membrane potential, and morphological features were characterized to elucidate the mechanisms of action. Treatment with punicalagin induced an increase in the extracellular concentrations of potassium and a release of cell constituents. A higher pH gradient, an increase in the intracellular pH, and cell membrane depolarization were observed after punicalagin treatment. Electron microscopy observations showed that the cell membrane structures of Salmonella Typhimurium were damaged by punicalagin. It is concluded that punicalagin inhibits the proliferation of Salmonella Typhimurium and destroys the integrity of the cell membrane, leading to a loss of cell homeostasis. These findings indicate that punicalagin has the potential to be developed as a future alternative to control Salmonella Typhimurium contamination in foods and reduce the risk of salmonellosis.

Antimicrobial Lipids from Plants and Marine Organisms: An Overview of the Current State-of-the-Art and Future Prospects

In the actual post-antibiotic era, novel ways of rethinking antimicrobial research approaches are more urgent than ever. Natural compounds with antimicrobial activity such as fatty acids and monoacylglycerols have been investigated for decades. Additionally, the interest in other lipid classes as antimicrobial agents is rising. This review provides an overview on the research about plant and marine lipids with potential antimicrobial activity, the methods for obtaining and analyzing these compounds, with emphasis on lipidomics, and future perspectives for bioprospection and applications for antimicrobial lipids. Lipid extracts or lipids isolated from higher plants, algae or marine invertebrates are promising molecules to inactivate a wide spectrum of microorganisms. These lipids include a variety of chemical structures. Present and future challenges in the research of antimicrobial lipids from natural origin are related to the investment and optimization of the analytical workflow based on lipidomics tools, complementary to the bioassay-guided fractionation, to identify the active compound(s). Also, further work is needed regarding the study of their mechanism of action, the structure-activity relationship, the synergistic effect with conventional antibiotics, and the eventual development of resistance to lipids, which, as far as is known, is unlikely.

Antimicrobial and antibiofilm activities of ursolic acid against carbapenem-resistant Klebsiella pneumoniae

Previous studies demonstrated that ursolic acid (UA) present in apple pomace displays antimicrobial activity against some microorganisms, but the underlying mechanisms associated with this activity remain unexplored. Furthermore, there are no reports on the effect of UA on carbapenem-resistant Klebsiella pneumoniae (CRKP). This study examined the antimicrobial activity and mode of action of UA against CRKP was examined. Minimum inhibitory concentration (MIC) of UA against CRKP was determined by the agar dilution method. Variations in the intracellular pH (pHin), ATP concentration, and cell membrane potential were measured to assess the influence of UA on the cell membrane. Our results show that UA was effective against CRKP at an MIC of 0.8 mg ml-1. UA disrupted the cell membrane integrity of CRKP, exhibited strong inhibitory effects against biofilm formation and biofilm-related gene expression, and inactivated CRKP cells encased in biofilms. Thus, UA shows promise for use in combination with other antibiotics to treat multidrug resistant K. pneumoniae infections.

Evaluation of the Effect of an Aqueous Extract of Azadirachta indica (Neem) Leaves and Twigs on Glycemic Control, Endothelial Dysfunction and Systemic Inflammation in Subjects with Type 2 Diabetes Mellitus - A Randomized, Double-Blind, Placebo-Controlled Clinical Study

PURPOSE

Neem tree (Azadirachta indica) offers different bioactives ranging from pesticides to therapeutic molecules, depending on which part of the plant is used and the extraction methodology and the solvent used. This study was aimed at evaluating the safety and efficacy of a standardized aqueous extract of Azadirachta indica leaves and twigs (NEEM) on glycemic control, endothelial dysfunction, and systemic inflammation in patients with type 2 diabetes mellitus (T2DM).

METHODS

In this randomized, double-blind, placebo-controlled clinical study (RCT), 80 T2DM subjects, who have already been on standard metformin therapy, received either 125 mg, 250 mg, 500 mg of NEEM or placebo twice daily for 12 weeks. Postprandial blood sugar level (PPBS), fasting blood sugar level (FBS), glycosylated hemoglobin (HbA1c), insulin resistance (IR), endothelial function, oxidative stress, systemic inflammation, IL-6 and TNF-α, platelet aggregation and lipid profile were assessed. Adverse drug reactions, if any, were noted. GraphPad Prism 8 was used to perform statistical analysis.

RESULTS

NEEM at the doses of 125, 250, and 500 mg BID significantly reduced PPBS (from 194.4±14 to 173.1±12.8mg/dL, 192.3±17.1 to 161.8±9.7mg/dL, and 205.9±7.2 to 159.3±7.1mg/dL, respectively), FBS (from 119.2±5.0 to 109.2±5.7mg/dL, 115.5±4.4 to 103.7±4.2mg/dL, and 120.7±4.2 to 97.3±3.7mg/dL, respectively), HbA1c (from 6.87 ± 0.4% to 6.64 ± 0.4%, 7.52 ± 0.4% to 6.86 ± 0.3%, and 7.78 ± 0.2% to 6.26 ± 0.4%, respectively), and IR (from 4.5 ± 1.2 to 3.4 ± 0.9, 3.8 ± 1.1 to 2.5 ± 0.6, and 4.6 ± 1.3 to 2.0 ± 0.6, respectively) compared to placebo. Also, NEEM significantly improved endothelial function, decreased oxidative stress and systemic inflammation compared to placebo. The efficacy was significant with all the doses, but no effect on platelet aggregation or lipid profile was observed.

CONCLUSION

NEEM may significantly ameliorate hyperglycemia, endothelial dysfunction, and systemic inflammation, on top of what metformin could do, in subjects with T2DM.

Antimicrobial Activity and Action Approach of the Olive Oil Polyphenol Extract Against Listeria monocytogenes

Olive oil polyphenol extract (OOPE) has been reported to have antibacterial activity; however, its effect on Listeria monocytogenes is less studied so far. This study, thus, aimed to reveal its antimicrobial activity and action approach against L. monocytogenes via evaluating the minimum inhibitory concentration (MIC) as well as the changes of intracellular adenosine 5′-triphosphate (ATP) concentration, cell membrane potential, bacterial protein, DNA, and cell morphology. The results showed that OOPE could inhibit the growth of L. monocytogenes with a measured MIC of 1.25 mg/ml. L. monocytogenes cells treated by OOPE showed significant reduction in intracellular ATP concentrations, bacterial protein, or DNA (p < 0.05), in comparison with those without any treatment. In addition, OOPE was observed to depolarize strain cells and alter cell morphology, resulting in damaged cell membrane and, thereby, leakage of cell fluid. These findings demonstrated that OOPE had inhibition on L. monocytogenes via its action on cells, suggesting its potential as a natural preservative.

In vitro assessment of the antifungal effects of neem powder added to polymethyl methacrylate denture base material

Background

Denture with antimicrobial activities is desirable to prevent Candida albican adhesion subsequently decreasing the susceptibility of denture stomatitis incidence. Azadirachta Indica, commonly known as Neem powder has antimicrobial effect but the effect of its addition to acrylic denture base on C. albicans adhesion has not been investigated. The aim of this study was determine whether adding neem powder to acrylic denture base materials could reduce Candida albicansadhesion.

Material and Methods

One hundred and twenty acrylic resin denture specimens were fabricated and divided into heat-polymerized (n=60) and auto-polymerized (n=60) groups. Each group was further divided into 6 groups (n=10) based on the neem concentration: 0, 0.5, 1, 1.5, 2 and 2.5 wt% of the polymer. After polymerization, the specimens were polished, stored in distilled water, sonicated, sterilized, submerged in artificial saliva containing C. albicans, and finally, placed in an incubator at 37°C. Slide counting and direct culture methods were used to assess the antifungal effects of the neem addition. An analysis of variance and post hoc Tukey’s test were performed for the data analysis (p≤0.05 was statistically significant).

Results

Based on the results, the neem addition significantly decreased the C. albicans count when compared to the control group (p≤0.05). Moreover, the count decreased as the neem concentration increased (lowest count with 2.5 wt%).

Conclusions

The results suggest that adding neem powder to acrylic resin denture base materials reduces the adhesion of C. albicans; therefore, the incorporation of neem could be a possible denture stomatitis prevention method.

Key words:Denture stomatitis, Candida albicans, Azadirachta indica, neem powder, denture base.

Natural Compounds as Anticancer Agents Targeting DNA Topoisomerases

DNA topoisomerases are important cellular enzymes found in almost all types of living cells (eukaryotic and prokaryotic). These enzymes are essential for various DNA metabolic processes e.g. replication, transcription, recombination, chromosomal decatenation etc. These enzymes are important molecular drug targets and inhibitors of these enzymes are widely used as effective anticancer and antibacterial drugs. However, topoisomerase inhibitors have some therapeutic limitations and they exert serious side effects during cancer chemotherapy. Thus, development of novel anticancer topoisomerase inhibitors is necessary for improving cancer chemotherapy. Nature serves as a repertoire of structurally and chemically diverse molecules and in the recent years many DNA topoisomerase inhibitors have been identified from natural sources. The present review discusses anticancer properties and therapeutic importance of eighteen recently identified natural topoisomerase inhibitors (from the year 2009 to 2015). Structural characteristics of these novel inhibitors provide backbones for designing and developing new anticancer drugs.

Evaluation of the Antibacterial Efficacy of Azadirachta Indica, Commiphora Myrrha, Glycyrrhiza Glabra Against Enterococcus Faecalis using Real Time PCR

AIM

To compare the antibacterial efficacy of Azadirachta indica (Neem), Commiphora myrrha (Myrrh), Glycyrrhiza glabra (Liquorice) with 2% Chlorhexidine (CHX) against E. faecalis by using Real Time PCR.

MATERIALS AND METHODS

A total of fifty teeth specimens (n=50) were inoculated with E. faecalis for 21 days. Specimens were divided into five groups (Group 1: Myrrh, Group 2: Neem, Group 3: Liquorice, Group 4: 2% CHX and Group 5: Saline (negative control)). The intracanal medicaments were packed inside the tooth. After 5 days, the remaining microbial load was determined by using real time PCR.

RESULTS

Threshold cycle (Ct) values of Myrrh extract, Neem extract, Liquorice Extract, 2% CHX and saline were found to be 30.94, 23.85, 21.38, 30.93 and 17.8 respectively.

CONCLUSION

Myrrh extract showed inhibition of E.faecalis equal to that of 2% CHX followed by Neem, Liquorice and Saline.

Antiherpetic Plants: A Review of Active Extracts, Isolated Compounds, and Bioassays

Herpes simplex is a disease that is widely distributed throughout the world. It is caused by herpes simplex virus type 1 (HSV-1) and simplex virus type 2 (HSV-2). The drugs of choice for treatment are acyclovir (ACV), Penciclovir (PCV) and other guanine analogues, which have the same mechanism of action. However, due to the constant increase of ACV-resistant strains in immunocompromised patients, it is necessary to find new treatment alternatives. It has been shown that natural products are a good alternative for the treatment of these diseases as well as being an excellent source of compounds with anti-herpetic activity, which may be useful for the development of new drugs and act through a mechanism of action different from ACV and PCV. This paper compiles reports on extracts and compounds isolated from plants that have anti-herpetic activity. We present an analysis of the solvents most widely used for extraction from plants as well as cells and commonly used methods for evaluating cytotoxic and anti-herpetic activity. Families that have a higher number of plants with anti-herpetic activity are evaluated, and we also highlight the importance of studies of mechanisms of action of extracts and compounds with anti-herpetic activity.

Aminomethylnaphthoquinones and HSV-1: in vitro and in silico evaluations of potential antivirals

BACKGROUND

Herpes simplex viruses (HSV) are leading causes of human infections which result in severe manifestations, especially in neonates, immunocompromised and/or transplanted individuals. Current HSV type-1 (HSV-1) resistance to standard antiviral agents is a therapeutic challenge, especially for treating immunocompromised patients.

METHODS

Herein we describe the promising antiviral profile of three 2-aminomethyl-3-hydroxy-1,4-naphthoquinones against HSV-1 using Vero cells.

RESULTS

The in silico theoretical analysis indicated that the lowest unoccupied molecular orbital (LUMO) and the conformational features of these molecules are important structural features for modulating their biological activity. Our in vitro results showed that these compounds have significant anti-HSV-1 activity comparable to acyclovir, the antiviral currently used clinically. Importantly two of them showed a lower cytotoxicity profile against Vero cells than acyclovir. The inhibitory mechanism analysis using a time-of-addition assay revealed that all compounds inhibit the late phase of lytic replication. Finally, the highest selectivity index of the first tested compound was almost twice as high as that of acyclovir.

CONCLUSIONS

Since resistance is still a problem for treating HSV infections, these compounds present a promising profile toward the development of new strategies for anti-HSV-1 therapy.

Sulfonoquinovosyl diacylglyceride selectively targets acute lymphoblastic leukemia cells and exerts potent anti-leukemic effects in vivo

DNA topoisomerase II inhibitors e.g. doxorubicin and etoposide are currently used in the chemotherapy for acute lymphoblastic leukemia (ALL). These inhibitors have serious side effects during the chemotherapy e.g. cardiotoxicity and secondary malignancies. In this study we show that sulfonoquinovosyl diacylglyceride (SQDG) isolated from Azadirachta indica exerts potent anti-ALL activity both in vitro and in vivo in nude mice and it synergizes with doxorubicin and etoposide. SQDG selectively targets ALL MOLT-4 cells by inhibiting catalytic activity of topoisomerase I enzyme and inducing p53 dependent apoptotic pathway. SQDG treatment induces recruitment of ATR at chromatin and arrests the cells in S-phase. Down-regulation of topoisomerase I or p53 renders the cells less sensitive for SQDG, while ectopic expression of wild type p53 protein in p53 deficient K562 cells results in chemosensitization of the cells for SQDG. We also show that constant ratio combinations of SQDG and etoposide or SDQG and doxorubicin exert synergistic effects on MOLT-4 cell killing. This study suggests that doses of etoposide/doxorubicin can be substantially reduced by combining SQDG with these agents during ALL chemotherapy and side effects caused can be minimized. Thus dual targeting of topoisomerase I and II enzymes is a promising strategy for improving ALL chemotherapy.

Effect of Neem (Azadirachta indica) on the Survival of Escherichia coli O157:H7 in Dairy Manure

Escherichia coli O157:H7 (EcO157) shed in cattle manure can survive for extended periods of time and intervention strategies to control this pathogen at the source are critical as produce crops are often grown in proximity to animal raising operations. This study evaluated whether neem (Azadirachta indica), known for its antimicrobial and insecticidal properties, can be used to amend manure to control EcO157. The influence of neem materials (leaf, bark, and oil) on the survival of an apple juice outbreak strain of EcO157 in dairy manure was monitored. Neem leaf and bark supplements eliminated the pathogen in less than 10 d with a D-value (days for 90% elimination) of 1.3 d. In contrast, nearly 4 log CFU EcO157/g remained after 10 d in neem-free manure control. The ethyl acetate extractable fraction of neem leaves was inhibitory to the growth of EcO157 in LB broth. Azadirachtin, a neem product with insect antifeedant properties, failed to inhibit EcO157. Application of inexpensive neem supplements to control pathogens in manure and possibly in produce fields may be an option for controlling the transfer of foodborne pathogens from farm to fork.

Validation of Antiviral Potential of Herbal Ethnomedicine

Natural products are the basis of treatment since the dawn of human civilization, and modern medicine has gradually developed, over the years, by scientific and observational efforts from traditional medicine. Today most of the synthetic drugs showed adverse and unacceptable side effects, however, impressive bioactivities with reduced toxicities were reported for many botanicals against several chronic or difficult-to-treat diseases. A whole range of viral diseases including human immunodeficiency virus/acquired immunodeficiency syndrome, severe acute respiratory syndrome, Rabies, Dengue, and Herpes need effective drugs. Considerable research has been carried out on the pharmacognosy, chemistry, pharmacology, and therapeutics of traditional medicines of diverse cultures, and many pharmaceutical companies have renewed their strategies for antiviral drug development where no effective drugs or vaccine exist. Thus, phytochemicals with antiviral potentials need to be studied in depth with standardization, chemical isolation, effectivity, molecular mechanism, along with in vivo toxicity and efficacy to reduce cost and time. This review will portray the scientific approaches and methodologies used for the development of antiviral leads from traditional medicines against selected genetically and functionally diverse viral infections.