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Here, we demonstrate the concerted inhibition of different influenza A virus (IAV) strains using a low-molecular-weight dual-action linear polymer. The 6'-sialyllactose and zanamivir conjugates of linear polyglycerol are optimized for simultaneous targeting of hemagglutinin and neuraminidase on the IAV surface. Independent of IAV subtypes, hemagglutination inhibition data suggest better adsorption of the heteromultivalent polymer than homomultivalent analogs onto the virus surface. Cryo-TEM images imply heteromultivalent compound-mediated virus aggregation. The optimized polymeric nanomaterial inhibits >99.9% propagation of various IAV strains 24 h postinfection in vitro at low nM concentrations and is up to 10000× more effective than the commercial zanamivir drug. In a human lung ex vivo multicyclic infection setup, the heteromultivalent polymer outperforms the commercial drug zanamivir and homomultivalent analogs or their physical mixtures. This study authenticates the translational potential of the dual-action targeting approach using small polymers for broad and high antiviral efficacy.

In the last decades, various efforts have been made to synthesize optimal glycotripods for targeting trimeric glycoproteins like asialoglycoprotein receptor, hemagglutinin, and langerin. All these trimeric glycoproteins have sugar binding pockets which are highly selective for a particular carbohydrate ligand. Optimized glycotripods are high affinity binders and have been used for delivering drugs or even applied as drug candidates. The selection of the tripodal base scaffold together with the length and flexibility of the linker between the scaffold and sugar residue, as important design parameters are discussed in this review.

Photodynamic therapy (PDT) is emerging as an efficient strategy to combat multidrug-resistant (MDR) cancer. However, the short half-life and limited diffusion of reactive oxygen species (ROS) undermine the therapeutic outcomes of this therapy. To address this issue, a tumor-targeting nanoplatform was developed to precisely deliver mitochondria- and endoplasmic reticulum (ER)-targeting PDT agents to desired sites for dual organelle-targeted PDT. The nanoplatform is constructed by functionalizing molybdenum disulfide (MoS

Flexible multivalent 3D nanosystems that can deform and adapt onto the virus surface via specific ligand–receptor multivalent interactions can efficiently block virus adhesion onto the cell. We here report on the synthesis of a 250 nm sized flexible sialylated nanogel that adapts onto the influenza A virus (IAV) surface via multivalent binding of its sialic acid (SA) residues with hemagglutinin spike proteins on the virus surface. We could demonstrate that the high flexibility of sialylated nanogel improves IAV inhibition by 400 times as compared to a rigid sialylated nanogel in the hemagglutination inhibition assay. The flexible sialylated nanogel efficiently inhibits the influenza A/X31 (H3N2) infection with IC50 values in low picomolar concentrations and also blocks the virus entry into MDCK‐II cells., Fighting influenza: Through the combination of flexibility and multivalent binding, a sialylated nanogel is able to bind and adapt onto the influenza A virus surface. The resulting flexible nanogel efficiently blocks the virus binding onto the cell and inhibits infection at low pm concentrations.

Herpes Simplex Virus-1 (HSV-1) with a diameter of 155–240 nm uses electrostatic interactions to bind with the heparan sulfate present on the cell surface to initiate infection. In this work, the initial contact using polysulfate-functionalized hydrogels is aimed to deter. The hydrogels provide a large contact surface area for viral interaction and sulfated hydrogels are good mimics for the native heparan sulfate. In this work, hydrogels of different flexibilities are synthesized, determined by rheology. Gels are prepared within an elastic modulus range of 10–1119 Pa with a mesh size of 80–15 nm, respectively. The virus binding studies carried out with the plaque assay show that the most flexible sulfated hydrogel performs the best in binding HSV viruses. These studies prove that polysulfated hydrogels are a viable option as HSV-1 antiviral compounds. Furthermore, such hydrogel networks are also physically similar to naturally occurring mucus gels and therefore may be used as mucus substitutes.

Two sugar PEG-based amphiphilic copolymers have been synthesized by Novozym®-435-catalyzed greener solvent free transesterification reaction of diastereomeric 2,6-anhydro-3,4,5-tri-O-benzyl-glucoheptitol and 2,6-anhydro-3,4,5-tri-O-benzyl-mannoheptitol with PEG-1000 diethyl ester in 80 and 76% yields, respectively. It has been observed that the configurational change at one of the carbons of diastereomeric 2,6-anhydro-heptitols has significant bearing on the degree of polymerization and characteristics of the synthesized polymers. Thus, the study of physico-chemical characteristics of synthesized anhydroglucoheptitol- and anhydromannoheptitol-PEG copolymers revealed that their aqueous solution forms spherical micelles of hydrodynamic diameters 11.2 and 6.4 nm, respectively. Micelles derived from both the amphiphilic copolymers have the potential to solubilize the hydrophobic dye, Nile red. Furthermore, a fluorescence microscopy study revealed that Nile red encapsulated micelles of synthesized amphiphilic copolymers uniformly internalized in A549 cells and thus can be used as a cargo carrier in biological systems. The viability of A549 cells was found to be very high even at a concentration of 500 μg mL−1 of copolymer indicating that they are cyto-compatible.

Self-assembly of non-ionic amphiphilic architectures into nanostructures with defined size, shape and morphology has garnered substantial momentum in the recent years due to their extensive applications in biomedicine. The manifestation of a wide range of morphologies such as micelles, vesicles, fibers, tubes, and toroids is thought to be related to the structure of amphiphilic architectures, in particular, the choice of the hydrophilic and hydrophobic parts. In this review, we look at different types of non-ionic small amphiphilic architectures and the factors that influence their self-assembly into various nanostructures in aqueous medium. In particular, we focus on the explored structural parameters that guide the formation of various nanostructures, and the ways these structures can be used in applications ranging from drug delivery to cell imaging.

We report a virus responsive hydrogel with a dual response. The method utilizes the optical properties of gold nanoparticles (AuNPs) and the high swelling capacity of polyol-based hydrogels to form a nanocomposite of AuNPs and polyols that produces both color changes and shrinkage in the presence of Influenza A virus particles.

The development of multivalent sialic acid-based inhibitors active against a variety of influenza A virus (IAV) strains has been hampered by high genetic and structural variability of the targeted viral hemagglutinin (HA). Here, we addressed this challenge by employing sialylated polyglycerols (PGs). Efficacy of prototypic PGs was restricted to a narrow spectrum of IAV strains. To understand this restriction, we selected IAV mutants resistant to a prototypic multivalent sialylated PG by serial passaging. Resistance mutations mapped to the receptor binding site of HA, which was accompanied by altered receptor binding profiles of mutant viruses as detected by glycan array analysis. Specifying the inhibitor functionalization to 2,6-α-sialyllactose (SL) and adjusting the linker yielded a rationally designed inhibitor covering an extended spectrum of inhibited IAV strains. These results highlight the importance of integrating virological data with chemical synthesis and structural data for the development of sialylated PGs toward broad anti-influenza compounds.

Inhibition of herpes simplex virus type 1 (HSV-1) binding to the host cell surface by highly sulfated architectures is among the promising strategies to prevent virus entry and infection. However, the structural flexibility of multivalent inhibitors plays a major role in effective blockage and inhibition of virus receptors. In this study, we demonstrate the inhibitory effect of a polymer scaffold on the HSV-1 infection by using highly sulfated polyglycerols with different architectures (linear, dendronized, and hyperbranched). IC50 values for all synthesized sulfated polyglycerols and the natural sulfated polymer heparin were determined using plaque reduction infection assays. Interestingly, an increase in the IC50 value from 0.03 to 374 nM from highly flexible linear polyglycerol sulfate (LPGS) to less flexible scaffolds, namely, dendronized polyglycerol sulfate and hyperbranched polyglycerol sulfate was observed. The most potent LPGS inhibits HSV-1 infection 295 times more efficiently than heparin, and we show that LPGS has a much reduced anticoagulant capacity when compared to heparin as evidenced by measuring the activated partial thromboplastin time. Furthermore, prevention of infection by LPGS and the commercially available drug acyclovir were compared. All tested sulfated polymers do not show any cytotoxicity at concentrations of up to 1 mg/mL in different cell lines. We conclude from our results that more flexible polyglycerol sulfates are superior to less flexible sulfated polymers with respect to inhibition of HSV-1 infection and may constitute an alternative to the current antiviral treatments of this ubiquitous pathogen.

A broad-spectrum heteromultivalent influenza inhibitor is developed by using the host cell membrane on an inverted virus scaffold., Here, we report the topology-matched design of heteromultivalent nanostructures as potent and broad-spectrum virus entry inhibitors based on the host cell membrane. Initially, we investigate the virus binding dynamics to validate the better binding performance of the heteromultivalent moieties as compared to homomultivalent ones. The heteromultivalent binding moieties are transferred to nanostructures with a bowl-like shape matching the viral spherical surface. Unlike the conventional homomultivalent inhibitors, the heteromultivalent ones exhibit a half maximal inhibitory concentration of 32.4 ± 13.7 μg/ml due to the synergistic multivalent effects and the topology-matched shape. At a dose without causing cellular toxicity, >99.99% reduction of virus propagation has been achieved. Since multiple binding sites have also been identified on the S protein of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), we envision that the use of heteromultivalent nanostructures may also be applied to develop a potent inhibitor to prevent coronavirus infection.

The recently emerging stem-cell artificial niche engineering in induced pluripotent stem cell (iPSCs) 3D cultures has provided enormous opportunities to fully utilize the potential of these cells in biomedical applications. Although a fully chemically defined niche environment can supply cells with desirable safety for clinical use, establishing an artificial degradable niche environment for the controlled release of proliferated cells under mild conditions is still a big challenge. Here, an advanced controlled releasable iPSC 3D artificial niche is reported based on dendritic polyglycerol and poly(N-isopropylacrylamide)-co-polyethylene glycol polymers via a physical–chemical cogelation strategy. Benefiting from the chemically defined synthetic materials and their precise cooperation by covalent cross-linking and physical phase transition, the cogelation-based artificial niche system can be adjusted with optimal parameters and owns high cell biocompatibility to support the robust production of high quality iPSCs with an excellent expansion efficiency. Moreover, the expanded cells can be released out of their niche environment controllably only by adjusting the temperature. Overall, this controlled release hydrogel scaffold shows great promise in iPSC 3D culture for downstream applications.

Linear and hyperbranched polyglycerol-based mannosides and fucosyllactosides were developed as nanomolar binders of mannose binding lectin (MBL) and DC-SIGN using label free microscale thermophoresis (MST) and surface plasmon resonance (SPR) techniques, respectively. While there was a small preference for hyperbranched polyglycerols in the case of MBL inhibitors, a clear advantage of ligand presentation on linear polyglycerol scaffolds was observed for DC-SIGN.

In this study, we demonstrate the concept of “topology‐matching design” for virus inhibitors. With the current knowledge of influenza A virus (IAV), we designed a nanoparticle‐based inhibitor (nano‐inhibitor) that has a matched nanotopology to IAV virions and shows heteromultivalent inhibitory effects on hemagglutinin and neuraminidase. The synthesized nano‐inhibitor can neutralize the viral particle extracellularly and block its attachment and entry to the host cells. The virus replication was significantly reduced by 6 orders of magnitude in the presence of the reverse designed nano‐inhibitors. Even when used 24 hours after the infection, more than 99.999 % inhibition is still achieved, which indicates such a nano‐inhibitor might be a potent antiviral for the treatment of influenza infection., Influenza meets its match: Based on the principle of topology matching, a potent nanoparticle‐based inhibitor for influenza A was designed that shows heteromultivalent inhibition of the receptor‐binding viral proteins. This inhibitor is capable of neutralizing influenza A virus extracellularly and blocking its interaction with the host cell receptors. This principle could potentially also be applied to the inhibition of other viruses with spiky surfaces.

Herein, the chemical synthesis and binding analysis of functionalizable rigid and flexible core trivalent sialosides bearing oligoethylene glycol (OEG) spacers interacting with spike proteins of influenza A virus (IAV) X31 is described. Although the flexible Tris‐based trivalent sialosides achieved micromolar binding constants, a trivalent binder based on a rigid adamantane core dominated flexible tripodal compounds with micromolar binding and hemagglutination inhibition constants. Simulation studies indicated increased conformational penalties for long OEG spacers. Using a systematic approach with molecular modeling and simulations as well as biophysical analysis, these findings emphasize on the importance of the scaffold rigidity and the challenges associated with the spacer length optimization.

The mucus layer is a hydrogel network that covers mucosal surfaces of the human body. Mucus has important protective properties that are related to its unique rheological properties, which are based on mucins being the main glycoprotein constituents. Mucin macromolecules entangle with one another and form a physical network that is instrumental for many important defense functions. Mucus derived from various human or animal sources is poorly defined and thus not suitable for many application purposes. Herein, a synthetic route is fabricated to afford a library of compositionally defined mucus-inspired hydrogels (MIHs). MIHs are synthesized by thiol oxidation to render disulfide bonds between the crosslinker ethoxylated trimethylolpropane tri(3-mercaptopropionate) (THIOCURE ETTMP 1300) and the linear precursors, dithiolated linear polyglycerol (LPG(SH)2 ) or polyethylene glycol (PEG(SH)2 ) of different molecular weights. The mixing ratio of linear polymers versus crosslinker and the length of the linear polymer are varied, thus delivering a library of compositionally defined mucin-inspired constructs. Their viscoelastic properties are determined by frequency sweeps at 25 and 37 °C and compared to the corresponding behavior of native human mucus. Here, MIHs composed of a 10:1 ratio of LPG(SH)2 and ETTMP 1300 are proved to be the best comparable to human airway mucus rheology.

Multivalent binding inhibitors are a promising new class of antivirals that prevent virus infections by inhibiting virus binding to cell membranes. The design of these inhibitors is challenging as many properties, for example, inhibitor size and functionalization with virus attachment factors, strongly influence the inhibition efficiency. Here, virus binding inhibitors are synthesized, the size and functionalization of which are inspired by mucins, which are naturally occurring glycosylated proteins with high molecular weight (MDa range) and interact efficiently with various viruses. Hyperbranched polyglycerols (hPGs) with molecular weights ranging between 10 and 2600 kDa are synthesized, thereby hitting the size of mucins and allowing for determining the impact of inhibitor size on the inhibition efficiency. The hPGs are functionalized with sialic acids and sulfates, as suggested from the structure of mucins, and their inhibition efficiency is determined by probing the inhibition of influenza A virus (IAV) binding to membranes using various methods. The largest, mucin-sized inhibitor shows potent inhibition at pm concentrations, while the inhibition efficiency decreases with decreasing the molecular weight. Interestingly, the concentration-dependent IAV inhibition shows a biphasic behavior, which is attributed to differences in the binding affinity of the inhibitors to the two IAV envelope proteins, neuraminidase, and hemagglutinin.

Inhibition of respiratory viruses is one of the most urgent topics as underlined by different pandemics in the last two decades. This impels the development of new materials for binding and incapacitation of the viruses. In this work, we have demonstrated that an optimal deployment of influenza A virus (IAV) targeting ligand sialic acid (SA) on a flexible 2D platform enables its binding and wrapping around IAV particles. A series of 2D sialylated platforms consisting graphene and polyglycerol are prepared with different degrees of SA functionalization around 10%, 30%, and 90% named as G-PG-SAL, G-PG-SAM, and G-PG-SAH, respectively. The cryo-electron tomography (Cryo-ET) analysis has proved wrapping of IAV particles by G-PG-SAM. A confocal-based colocalization assay established for these materials has offered the comparison of binding potential of sialylated and non-sialylated nanoplatforms for IAV. With this method, we have estimated the binding potential of the G-PG-SAM and G-PG-SAH sheets for IAV particles around 50 and 20 times higher than the control sheets, respectively, whereas the low functionalized G-PG-SAL have not shown any significant colocalization value. Moreover, optimized G-PG-SAM exhibits high potency to block IAV from binding with the MDCK cells.

Indocyanine green (ICG) is a near-infrared dye for wide-ranging applications, but its utility for biological studies is limited due to poor aqueous stability and concentration-dependent aggregation. Aqueous polymeric micelles/micellar aggregates of amphiphilic copolymers could be used to protect indocyanine green (ICG) by encapsulation, which is used in laser-mediated photothermal therapy (PTT) and photodynamic therapy (PDT). The sugar–PEG-based amphiphilic copolymers were synthesized using Novozym 435-catalyzed transesterification reaction under bulk conditions for encapsulation of ICG. A dye loading study revealed that micelles derived from copolymers having decanoylated and myristoylated sugar moieties encapsulate 62% and 92% of the ICG, respectively, with a multi-fold increase in its aqueous stability. Furthermore, an efficient internalization of micelles of acylated amphiphilic copolymers in aqueous medium was demonstrated by incubating cells with Nile red-encapsulated amphiphiles.

Interfacial multivalent interactions at pathogen-cell interfaces can be competitively inhibited by multivalent scaffolds that prevent pathogen adhesion to the cells during the initial stages of infection. The lack of understanding of complex biological systems makes the design of an efficient multivalent inhibitor a toilsome task. Therefore, we have highlighted the main issues and concerns associated with blocking pathogen at interfaces, which are dependent on the nature and properties of both multivalent inhibitors and pathogens, such as viruses and bacteria. The challenges associated with different cores or carrier scaffolds of multivalent inhibitors are concisely discussed with selected examples.

The coupling of peptides to polyglycerol carriers represents an important route towards the multivalent display of protein ligands. In particular, the inhibition of low affinity intracellular protein–protein interactions can be addressed by this design. We have applied this strategy to develop binding partners for FBP21, a protein which is important for the splicing of pre-mRNA in the nucleus of eukaryotic cells. Firstly, by using phage display the optimized sequence WPPPPRVPR was derived which binds with KDs of 80 μM and 150 µM to the individual WW domains and with a KD of 150 μM to the tandem-WW1–WW2 construct. Secondly, this sequence was coupled to a hyperbranched polyglycerol (hPG) that allowed for the multivalent display on the surface of the dendritic polymer. This novel multifunctional hPG-peptide conjugate displayed a KD of 17.6 µM which demonstrates that the new carrier provides a venue for the future inhibition of proline-rich sequence recognition by FBP21 during assembly of the spliceosome.

For antiviral drug design, especially in the field of influenza virus research, potent multivalent inhibitors raise high expectations for combating epidemics and pandemics. Among a large variety of covalent and non-covalent scaffold systems for a multivalent display of inhibitors, we created a simple supramolecular platform to enhance the antiviral effect of our recently developed antiviral Peptide B (PeBGF), preventing binding of influenza virus to the host cell. By conjugating the peptide with stearic acid to create a higher-order structure with a multivalent display, we could significantly enhance the inhibitory effect against the serotypes of both human pathogenic influenza virus A/Aichi/2/1968 H3N2, and avian pathogenic A/FPV/Rostock/34 H7N1 in the hemagglutination inhibition assay. Further, the inhibitory potential of stearylated PeBGF (C18-PeBGF) was investigated by infection inhibition assays, in which we achieved low micromolar inhibition constants against both viral strains. In addition, we compared C18-PeBGF to other published amphiphilic peptide inhibitors, such as the stearylated sugar receptor mimicking peptide (Matsubara et al. 2010), and the “Entry Blocker” (EB) (Jones et al. 2006), with respect to their antiviral activity against infection by Influenza A Virus (IAV) H3N2. However, while this strategy seems at a first glance promising, the native situation is quite different from our experimental model settings. First, we found a strong potential of those peptides to form large amyloid-like supramolecular assemblies. Second, in vivo, the large excess of cell surface membranes provides an unspecific target for the stearylated peptides. We show that acylated peptides insert into the lipid phase of such membranes. Eventually, our study reveals serious limitations of this type of self-assembling IAV inhibitors.

Inhibition of influenza A virus infection by multivalent sialic acid inhibitors preventing viral hemagglutinin binding to host cells of the respiratory tract is a promising strategy. However, optimal geometry and optimal ligand presentation on multivalent scaffolds for efficient inhibition both in vitro and in vivo application are still unclear. Here, by comparing linear and dendritic polyglycerol sialosides (LPGSA and dPGSA) we identified architectural requirements and optimal ligand densities for an efficient multivalent inhibitor of influenza virus A/X31/1 (H3N2). Due to its large volume, the LPGSA at optimal ligand density sterically shielded the virus significantly better than the dendritic analog. A statistical mechanics model rationalizes the relevance of ligand density, morphology, and the size of multivalent scaffolds for the potential to inhibit virus-cell binding. Optimized LPGSA inhibited virus infection at IC50 in the low nanomolar nanoparticle concentration range and also showed potent antiviral activity against two avian influenza strains A/Mallard/439/2004 (H3N2) and A/turkey/Italy/472/1999 (H7N1) post infection. In vivo application of inhibitors clearly confirmed the higher inhibition potential of linear multivalent scaffolds to prevent infection. The optimized LPGSA did not show any acute toxicity, and was much more potent than the neuraminidase inhibitor oseltamivir carboxylate in vivo. Combined application of the LPGSA and oseltamivir carboxylate revealed a synergistic inhibitory effect and successfully prevented influenza virus infection in mice.

The influenza A virus infects target cells through multivalent interactions of its major spike proteins, hemagglutinin (HA) and neuraminidase (NA), with the cellular receptor sialic acid (SA). HA is known to mediate the attachment of the virion to the cell, whereas NA enables the release of newly formed virions by cleaving SA from the cell. Because both proteins target the same receptor but have antagonistic functions, virus infection depends on a properly tuned balance of the kinetics of HA and NA activities for viral entry to and release from the host cell. Here, dynamic single-molecule force spectroscopy, based on scanning force microscopy, was employed to determine these bond-specific kinetics, characterized by the off rate k(off), rupture length x(β) and on rate k(on), as well as the related free-energy barrier ΔG and the dissociation constant K(D). Measurements were conducted using surface-immobilized HA and NA of the influenza A virus strain A/California/04/2009 and a novel, to our knowledge, synthetic SA-displaying receptor for functionalization of the force probe. Single-molecule force spectroscopy at force loading rates between 100 and 50,000 pN/s revealed most probable rupture forces of the protein-SA bond in the range of 10–100 pN. Using an extension of the widely applied Bell-Evans formalism by Friddle, De Yoreo, and co-workers, it is shown that HA features a smaller x(β), a larger k(off) and a smaller ΔG than NA. Measurements of the binding probability at increasing contact time between the scanning force microscopy force probe and the surface allow an estimation of K(D), which is found to be three times as large for HA than for NA. This suggests a stronger interaction for NA-SA than for HA-SA. The biological implications in regard to virus binding to the host cell and the release of new virions from the host cell are discussed.

Sugar-PEG-based polymers were synthesized by enzymatic copolymerization of 4-C-hydroxymethyl-1,2-O-isopropylidene-β-L-threo-pentofuranose/4-C-hydroxymethyl-1,2-O-benzylidene-β-L-threo-pentofuranose/4-C-hydroxymethyl-1,2-O-isopropylidene-3-O-pentyl-β-L-threo-pentofuranose with PEG-600 dimethyl ester using Novozyme-435 (Candida antarctica lipase immobilized on polyacrylate). Carbohydrate monomers were obtained by the multistep synthesis starting from diacetone-D-glucose and PEG-600 dimethyl ester, which was in turn obtained by the esterification of the commercially available PEG-600 diacid. Aggregation studies on the copolymers revealed that in aqueous solution those polymers bearing the hydrophobic pentyl/benzylidene moiety spontaneously self-assembled into supramolecular aggregates. The critical aggregation concentration (CAC) of polymers was determined by surface tension measurements, and the precise size of the aggregates was obtained by dynamic light scattering. The polymeric aggregates were further explored for their drug encapsulation properties in buffered aqueous solution of pH 7.4 (37 °C) using nile red as a hydrophobic model compound by means of UV/vis and fluorescence spectroscopy. There was no significant encapsulation in polymer synthesized from 4-C-hydroxymethyl-1,2-O-isopropylidene-β-L-threo-pentofuranose because this sugar monomer does not contain a big hydrophobic moiety as the pentyl or the benzylidene moiety. Nile red release study was performed at pH 5.0 and 7.4 using fluorescence spectroscopy. The release of nile red from the polymer bearing benzylidene moiety and pentyl moiety was observed with a half life of 3.4 and 2.0 h, respectively at pH 5.0, whereas no release was found at pH 7.4.

Coumarins, a well-known class of naturally occurring compounds, display a remarkable array of biochemical and pharmacological actions, some of which suggest that certain members of this group of compounds may significantly affect the function of various mammalian cellular systems. The development of coumarins as antioxidant agents has attracted much attention in recent years. Coumarins afford an opportunity for the discovery of new antioxidants with truly novel mechanisms of action. This review updates and expands the 2006 review by the same author. The review considers and incorporates the most recently published literature on coumarins as related to their antioxidant properties. A lot of coumarins have been identified from natural sources, especially green plants. These natural compounds have served as valuable leads for further design and synthesis of more active analogues. Beyond doubt, a deep understanding of the mechanisms of existing synthetic and natural coumarins will build the basis for the rational design.

Objectives To evaluate the potential of a novel dihydropyrimidinone, ethyl 4-(4′-heptanoyloxyphenyl)-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylate (H-DHPM), as a calcium channel blocker, endowed with the ability to inhibit platelet aggregation effectively. Methods In-vitro and in-vivo studies were conducted for the determination of antiplatelet activity using adenosine diphosphate (ADP), collagen or thrombin as inducers. Calcium channel blocking activity and nitric oxide synthase (NOS) activity were monitored. Lipopolysaccharide (LPS)-mediated prothrombotic conditions were developed in rats to study the efficacy of H-DHPM to suitably modulate the inflammatory mediators such as inducible NOS (iNOS) and tissue factor. The cGMP level and endothelial NOS (eNOS) expression were checked in aortic homogenate of LPS-challenged rats pretreated with H-DHPM. The effect of H-DHPM on FeCl3-induced thrombus formation in rats was examined. Key findings The concentrations of H-DHPM required to give 50% inhibition (IC50) of in-vitro platelet aggregation induced by ADP, collagen or thrombin were 98.2 ± 2.1, 74.5 ± 2.3 and 180.7 ± 3.4 µm, respectively. H-DHPM at a dose of 52.0 ± 0.02 mg/kg (133 µmol/kg) was found to optimally inhibit ADP-induced platelet aggregation in-vivo. The level of nitric oxide was found to be up to 9 ± 0.08-fold in H-DHPM-treated platelets in-vitro and 8.2 ± 0.05-fold in H-DHPM-pretreated rat platelets in-vivo compared with control. OH-DHPM, the parent compound was found to be ineffective both in-vitro and in-vivo. H-DHPM-pretreated rats were able to resist significantly the prothrombotic changes caused by LPS by blunting the expression of iNOS, tissue factor and diminishing the increased level of cGMP to normal. H-DHPM enhanced the eNOS expression in aorta of rats treated with LPS. H-DHPM displayed synergy with antiplatelet activity of aspirin even at lower doses. H-DHPM was found to inhibit the LPS-induced platelet aggregation in younger as well as older rats. H-DHPM exhibited the ability to markedly decrease FeCl3-induced thrombus formation in rats. Conclusions H-DHPM has the attributes of a promising potent antiplatelet candidate molecule that should attract further study. H-DHPM displayed antiplatelet activity both in vivo and in vitro, which was due partially by lowering the intraplatelet calcium concentration.

Regio- and enantioselective synthesis of (S)-(+)-3-arylamino-1-chloropropan-2-ols has been achieved by the epoxide ring opening of (±)-epichlorohydrin with different aromatic amines in the presence of Candida rugosa lipase. Activities of seven model (S)-(+)-3-arylamino-1-chloropropan-2-ols, out of 10 compounds synthesized, have been evaluated for the inhibition of tumor necrosis factor-α TNF-α) induced expression of intercellular adhesion molecule-1 (ICAM-1), which is one of the factors responsible for the modulation of inflammation in biological systems; (S)-(+)-1-chloro-3-(2'-chlorophenylamino)-propan-2-ol has been found to exhibit highest activity, that is, 86% inhibition of TNF-α induced expression of ICAM-1 at a concentration of 40 μg/ml.

A series of 3-(N-alkyl-N-phenylamino)propan-2-ol derivatives were synthesized from epichlorohydrine in a multi-step strategy and were evaluated as Src kinase inhibitors. First, epoxy ring opening of epichlorohydrine was carried out in the presence of N-alkylanilines to yield 3-(N-alkyl-N-phenylamino)-1-chloro-propan-2-ol derivatives using Ca(OTf)2 as catalyst based on our previous studies [1] . Second, ring closure was performed under basic conditions to afford N-epoxymethyl N-alkylaniline derivatives. Finally, the epoxide ring opening with four different secondary amines and three nucleobases afforded the final products, i.e., a series of β-amino alcohols. All compounds were screened for their inhibitory activity against Src kinase and anticancer activity on human breast carcinoma cells, BT-20 cell line. Among all compounds, 3-N-methyl-N-phenylamino-1-(pyrrolidin-1-yl)propan-2-ol (13b) exhibited the highest inhibitory potency (IC50 = 66.1 μM) against Src kinase. Structure-activity relationship studies suggested that the incorporation of bulky groups at position 1 and N-substitution with groups larger than methyl moiety, reduced the inhibitory potency of the compound significantly. Compounds 3-(N-ethyl-N-phenylamino-)-1-(4-methylpiperazin-1-yl)propan-2-ol (14c) and 3-(N-ethyl-N-phenylamino)-1-(thymine-1-yl)propan-2-ol (17) were found to inhibit the growth of breast carcinoma cells by approximately 45–49% at concentration of 50 μM.

Objective : An outbreak of measles was investigated in the periurban areas of Chandigarh Union Territory, during the months of December 1998 to February 1999. Mainly the children below 15 years of age were affected. The children of migrant labourers belonging to the neighbouring states of Uttar Pradesh and Bihar constituted the majority of population in the area under study. They belonged to lower socio economic status with low immunization coverage.Methods : A total of 2968 houses were surveyed for epidemiological investigations in the areas of colony No. 5, Ramdarbar, Palsora and Pandit colony of Kajheri, covering a population of 14,601 and 7.3% (216/2968) of families were affected in the outbreak.Results : Two hundred and eighty three cases of measles were reported with an attack rate of 4.5% and male to female ratio of (M:F) 5.3%:3.6%. Among the measles cases, 48.8% had received measles vaccination. The outbreak was investigated by detecting measles specific IgG/IgM antibodies either in acute or convalescent serum samples or both. Due to inadequate surveillance system and containment measures, the outbreak was in full swing during the winter months. Measles related complications were reported in 31.1% cases (i.e. diarrhoea in 15.2% and Pneumonia is 7.1%).Conclusion : Following smallpox and guinea worm eradication, WHO’S next thrust, is on eradication of poliomyelitis and measles. Hence, strengthening of disease surveillance as well as vaccination policies are mandatory to achieve disease control in these areas.

Dendritic polymers have gained significant attention in the last two decades due to their size, shape, and multifunctionality. They have emerged as potential scaffolds for drug delivery applications. This chapter deals with the many recently developed applications of dendritic polymers in targeted drug delivery. The general properties of the dendritic polymers as drug delivery systems are discussed with special focus on active or passive delivery of conjugated or encapsulated drugs in targeting tumors, brain, skin, and inflammation. Some in vivo studies are discussed where dendrimer–drug conjugates were not only found to be active against aggressive tumor models but also showed better antitumor efficacy over the free drug. We also describe targeted gene delivery for the treatment of different disorders and diseases. Cellular penetration properties of the dendritic polymers without any targeting ligands, specifically in the inflammatory tissues, are highlighted as well. The extreme versatility of dendritic polymers with extensive research efforts is underway, leading to the development of targeted drug delivery systems for wide clinical use.

Pathogens adhere to the host cells during the first steps of infection through multivalent interactions which involve protein–glycan recognition. Multivalent interactions are also involved at different stages of immune response. Insights into these multivalent interactions generate a way to use suitable carbohydrate ligands that are attached to a basic scaffold consisting of e.g., dendrimer, polymer, nanoparticle, etc., with a suitable linker. Thus a multivalent architecture can be obtained with controllable spatial and topology parameters which can interfere with pathogen adhesion. Multivalent glycoconjugates bearing natural or unnatural carbohydrate antigen epitopes have also been used as carbohydrate based vaccines to stimulate an innate and adaptive immune response. Designing and synthesizing an efficient multivalent architecture with optimal ligand density and a suitable linker is a challenging task. This review presents a concise report on the endeavors to potentially use multi- and polyvalent glycoconjugates as vaccines as well as anti-infectious and anti-inflammatory drug candidates.

Investigations on the role of intracellular Ca2+ ion concentration in the mechanism of development of COPD in smokers and non-smokers were carried out. The intracellular Ca2+ levels were found to be increased in human lymphocytes in patients with COPD as compared to non-smokers and smokers without COPD. The investigations reveal an association in altered intracellular Ca2+ regulation in lymphocytes and severity of COPD, by means of significant activation of Protein kinase C and inducible nitric oxide synthase (iNOS). The effect of a novel calcium channel blocker ethyl 4-(4′-heptanoyloxyphenyl)-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylate (H-DHPM) as a potential candidate for the treatment of COPD was also investigated. H-DHPM treated cells showed a decrease in intracellular Ca2+ level as compared to the control cells. Molecular studies were carried out to evaluate the expression profile of NOS isoforms in human lymphocytes and it was shown that H-DHPM decreases the increased iNOS in COPD along with reestablishing the normal levels of endothelial nitric oxide synthase (eNOS). The results of H-DHPM were comparable with those of Amlodipine, a known calcium channel blocker. Calcium channel blocker H-DHPM proves to be a potential candidate for the treatment of COPD and further clinical studies are required to prove its role in the treatment of pulmonary hypertension (PH).

Multivalency is a widespread phenomenon in many biological systems, and inevitable for specific surface-surface interactions. The influenza virus provides a suitable system for studying multivalent interactions as it is covered by a densely packed layer of hemagglutinin (HA), which provides the virus high affinity to the host cells glycocalyx by multivalent interactions. To prevent such interactions and thus, infection, one promising strategy is the use of inhibitors presenting multiple HA receptors. For efficient inhibition, we investigated the optimal spatial arrangement, and amount of ligands of multivalent structures, among others multivalent polyglycerols and DNA-PNA heteroduplexes. Natural receptors such as sialic acid or peptide fragments from HA antibodies, form the basis of our multivalent constructs. In order to determine exact distances between HA binding sites, we introduced bivalent DNA-PNA heteroduplexes, presenting sialic acid with distinct distances, and thus serving as molecular rulers. Inhibition of fluorescent virions to red blood cells by heteroduplexes was assessed by flow cytometry measurement. By this strategy, we determined the spatial arrangement of sialic acid for optimal binding to virus at angstrom resolution. Microscale thermophoresis (MST) technology served as an independent and complementary approach to assess binding. Here, we detected nanomolar dissociation constants to full virus particles free in solution. In some instances, we observed multiphasic binding kinetics of multivalent structures to influenza virions. These studies are not only highly relevant for inhibition of virus infection, but also to provide new insights on the fundamentals of multivalent interactions.