Hydrophobic tail length, degree of fluorination and headgroup stereochemistry are determinants of the biocompatibility of (fluorinated) carbohydrate surfactants

Glycolipids mimicking biosurfactants of the synthetic origin as new immunomodulating and anticandidal derivatives

The immunobiological effectivity of glycolipids mimicking biosurfactants of the synthetic origin was followed up using macrophages cell line RAW264.7. These derivatives with different number of mannose units connected glycosidically or through triazole linker, and all having octyl aglycone, were evaluated with respect to their structure - immunomodulation activity relationship. This comparative study showed that the structural variations of the selected derivatives influenced the immunobiological cell behaviour as concerned pro-inflammatory TNF-α, IL-6, IL-1α, IL-17, IL-12 and anti-inflammatory IL-10 cytokines production and enhancement of RAW264.7 cell proliferation. The derivatives with mannose units linked through triazole linkers exerted in some cases stronger immunomodulative potency than (di)mannosides. On the other hand, a presence of triazole linker is a less favourable for an effective candidacidal activity as determined by in vitro using Candida albicans biofilm. The design of new defined immunomodulating formulas of the synthetic origin as possible antifungal agents and prospective participants in drug delivery systems may be of interest.

Chemical synthesis of amphiphilic glycoconjugates: Access to amino, fluorinated and sulfhydryl oleyl glucosides

Amphiphilic glycoconjugates offer an important prospect for development as chemical biology tools and biosurfactants. The chemical synthesis of such materials is required to expedite such prospect, compounded by the example of oleyl glycosides. Herein, we report a mild and reliable glycosylation method to access oleyl glucosides, glycosidating oleyl alcohol with α-trichloroacetimidate donors. We demonstrate capability for this methodology, extending it to synthesise the first examples of pyranose-component fluorination and sulfhydryl modifications within glucosides and glucosamines of oleyl alcohol. These compounds provide an exciting series of tools to explore processes and materials that utilise oleyl glycosides, including as probes for glycosphingolipid metabolism.

Achyrocline satureioides Hydroalcoholic Extract as a Hypoallergenic Antimicrobial Substitute of Natural Origin for Commonly Used Preservatives in Cosmetic Emulsions

Achyrocline satureioides is a South American herb used in traditional medicine to treat a wide range of ailments. The healing and antimicrobial effects of this plant have already been covered by many studies, which have confirmed its beneficial effects on human health. In this study, the antimicrobial effect of A. satureioides hydroalcoholic extract against Escherichia coli ATCC10536, Staphylococcus aureus ATCC25923, Staphylococcus epidermidis ATCC12228 and Lactobacillus acidophilus INCQS00076 was determined. The cytotoxicity of the extract was tested on human HaCaT keratinocytes showing very favourable effects on the proliferation and renewal of keratinocytes. According to the results of the HPLC and GC-MS analyses, the lyophilized extract contained only a minimal amount of fragrance allergens. The extract was then used in two cosmetic formulations, and one of them showed a significant synergistic interaction with other cosmetic components. We suggest the use of A.satureioides hydroalcoholic extract as a suitable antimicrobial component of natural origin for cosmetic preparations as a substitute for commonly used preservatives that can cause skin irritation and as a material with its own biological activity.

Antimicrobial Activity of Gelatin Nanofibers Enriched by Essential Oils against Cutibacterium acnes and Staphylococcus epidermidis

Acne vulgaris is a prevalent skin condition that is caused by an imbalance in skin microbiomes mainly by the overgrowth of strains such as Cutibacterium acnes and Staphylococcus epidermidis which affect both teenagers and adults. Drug resistance, dosing, mood alteration, and other issues hinder traditional therapy. This study aimed to create a novel dissolvable nanofiber patch containing essential oils (EOs) from Lavandula angustifolia and Mentha piperita for acne vulgaris treatment. The EOs were characterized based on antioxidant activity and chemical composition using HPLC and GC/MS analysis. The antimicrobial activity against C. acnes and S. epidermidis was observed by the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The MICs were in the range of 5.7-9.4 μL/mL, and MBCs 9.4-25.0 μL/mL. The EOs were integrated into gelatin nanofibers by electrospinning and SEM images of the fibers were taken. Only the addition of 20% of pure essential oil led to minor diameter and morphology alteration. The agar diffusion tests were performed. Pure and diluted Eos in almond oil exhibited a strong antibacterial effect on C. acnes and S. epidermidis. After incorporation into nanofibers, we were able to focus the antimicrobial effect only on the spot of application with no effect on the surrounding microorganisms. Lastly, for cytotoxicity evaluation, and MTT assay was performed with promising results that samples in the tested range had a low impact on HaCaT cell line viability. In conclusion, our gelatin nanofibers containing EOs are suitable for further investigation as prospective antimicrobial patches for acne vulgaris local treatment.

Oleaginous Yeast Extracts and Their Possible Effects on Human Health

Four non-conventional oleaginous and pigmented yeast strains of Metschnikowia pulcherrima, Cystofilobasidium infirmominiatum, Phaffia rhodozyma, and Rhodotorula kratochvilovae were used in this study. Complex yeast extracts were prepared and tested for biological activity, safety, and effect on human health. In this paper, we measured the antioxidant activity and antimicrobial effect of yeast biomass as a whole and their extracts to compare the influence of carotenoids and other bioactive substances in the studied biomass. All yeast extracts exhibited a significant dose-dependent antimicrobial effect against both G+ and G- bacteria and had a strong antioxidant effect. No cytotoxicity in the mouse melanoma B16F1 cell line was found in concentrations up to 20% of rehydrated biomass in cell medium. All of the extracts were cytotoxic at a concentration of 5 mg of extract/g of dry biomass. All the pigmented yeast extracts showed some positive results for apoptosis of murine melanoma cell lines and are therefore strong candidates positively effect human health. Red yeast cell biomass is a prospective material with many attractive biological functions and can be used in the food industry, as a pharmaceutical material, or in the feed industry.

Prenylated phenolics from Morus alba against MRSA infections as a strategy for wound healing

Antimicrobial resistance is a public health threat and the increasing number of multidrug-resistant bacteria is a major concern worldwide. Common antibiotics are becoming ineffective for skin infections and wounds, making the search for new therapeutic options increasingly urgent. The present study aimed to investigate the antibacterial potential of prenylated phenolics in wound healing. Phenolic compounds isolated from the root bark of Morus alba L. were investigated for their antistaphylococcal potential both alone and in combination with commonly used antibiotics. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by microdilution and agar method. Synergy was investigated using the checkerboard titration technique. Membrane-disrupting activity and efflux pump inhibition were evaluated to describe the potentiating effect. Prenylated phenolics inhibited bacterial growth of methicillin-resistant Staphylococcus aureus (MRSA) at lower concentrations (MIC 2-8 μg/ml) than commonly used antibiotics. The combination of active phenolics with kanamycin, oxacillin, and ciprofloxacin resulted in a decrease in the MIC of the antimicrobial agent. Kuwanon C, E, T, morusin, and albafuran C showed synergy (FICi 0.375-0.5) with oxacillin and/or kanamycin. Prenylated phenolics disrupted membrane permeability statistically significantly (from 28 ± 16.48% up to 73 ± 2.83%), and membrane disruption contributes to the complex antibacterial activity against MRSA. In addition, kuwanon C could be considered an efflux pump inhibitor. Despite the antibacterial effect on MRSA and the multiple biological activities, the prenylated phenolics at microbially significant concentrations have a minor effect on human keratinocyte (HaCaT) viability. In conclusion, prenylated phenolics in combination with commonly used antibiotics are promising candidates for the treatment of MRSA infections and wound healing, although further studies are needed.

Degradation of P(3HB-co-4HB) Films in Simulated Body Fluids

A novel model of biodegradable PHA copolymer films preparation was applied to evaluate the biodegradability of various PHA copolymers and to discuss its biomedical applicability. In this study, we illustrate the potential biomaterial degradation rate affectability by manipulation of monomer composition via controlling the biosynthetic strategies. Within the experimental investigation, we have prepared two different copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate—P(3HB-co-36 mol.% 4HB) and P(3HB-co-66 mol.% 4HB), by cultivating the thermophilic bacterial strain Aneurinibacillus sp. H1 and further investigated its degradability in simulated body fluids (SBFs). Both copolymers revealed faster weight reduction in synthetic gastric juice (SGJ) and artificial colonic fluid (ACF) than simple homopolymer P3HB. In addition, degradation mechanisms differed across tested polymers, according to SEM micrographs. While incubated in SGJ, samples were fragmented due to fast hydrolysis sourcing from substantially low pH, which suggest abiotic degradation as the major degradation mechanism. On the contrary, ACF incubation indicated obvious enzymatic hydrolysis. Further, no cytotoxicity of the waste fluids was observed on CaCO-2 cell line. Based on these results in combination with high production flexibility, we suggest P(3HB-co-4HB) copolymers produced by Aneurinibacillus sp. H1 as being very auspicious polymers for intestinal in vivo treatments.

Facilitating trehalose entry into hRBCs at 4 °C by alkylated ε-poly(L-lysine) for glycerol-free cryopreservation

Currently, glycerol is a conventional cryoprotectant of human red blood cells (hRBCs), but the time-consuming thawing and deglycerolization processes are essential before transfusion. Much of the research up to now has been conducted on the delivery of impermeable trehalose to hRBCs at 37 °C, but the cryoprotective effect of trehalose and deterioration of cells still remain challenging. Encouraged by the interaction of hydrophobic or cationic groups on cell membranes and osmotic stabilization, herein, we propose a novel cryopreservation system to facilitate trehalose entry into hRBCs at 4 °C and pH 7.4. High intracellular trehalose contents and cryosurvival of hRBCs were achieved with small function variations via the assistance of self-assembled nanoparticles of alkylated ε-poly(L-lysine) (ε-PL) along with poly(vinyl pyrrolidone) (PVP). The effect of amphipathic alkylated ε-PL with various alkyl chains and grafting ratios on membrane perturbation with protection of PVP was systematically investigated. Overall, by the combination of alkylated ε-PL and PVP, the intracellular trehalose could be enhanced to 109.7 ± 6.1 mM and subsequently hRBC cryosurvival reached 91.7 ± 5.5%, significantly higher than those containing trehalose only, 11.9 ± 1.1 mM and 50.0 ± 2.1%, respectively. It was observed that the biocompatible trehalose-loading system could benefit glycerol-free cryopreservation of hRBCs and also provide a feasible way for impermeable biomacromolecule delivery.

In Search of Effective Anticancer Agents-Novel Sugar Esters Based on Polyhydroxyalkanoate Monomers

Cancer is one of the deadliest illness globally. Searching for new solutions in cancer treatments is essential because commonly used mixed, targeted and personalized therapies are sometimes not sufficient or are too expensive for common patients. Sugar fatty acid esters (SFAEs) are already well-known as promising candidates for an alternative medical tool. The manuscript brings the reader closer to methods of obtaining various SFAEs using combined biological, chemical and enzymatic methods. It presents how modification of SFAE's hydrophobic chains can influence their cytotoxicity against human skin melanoma and prostate cancer cell lines. The compound's cytotoxicity was determined by an MTT assay, which followed an assessment of SFAEs' potential metastatic properties in concentrations below IC50 values. Despite relatively high IC50 values (63.3-1737.6 μM) of the newly synthesized SFAE, they can compete with other sugar esters already described in the literature. The chosen bioactives caused low polymerization of microtubules and the depolymerization of actin filaments in nontoxic levels, which suggest an apoptotic rather than metastatic process. Altogether, cancer cells showed no propensity for metastasis after treating them with SFAE. They confirmed that lactose-based compounds seem the most promising surfactants among tested sugar esters. This manuscript creates a benchmark for creation of novel anticancer agents based on 3-hydroxylated fatty acids of bacterial origin.

Approaches to the Synthesis of Perfluoroalkyl-Modified Carbohydrates and Derivatives: Thiosugars, Iminosugars, and Tetrahydro(thio)pyrans

Fluoroalkyl-substituted carbohydrates play relevant roles in diverse areas such as supramolecular chemistry, glycoconjugation, liquid crystals, and surfactants, with direct applications as wetting, antifreeze, and coating agents. In light of these promising applications, new methodologies for the late-stage incorporation of fluoroalkyl R_F groups into carbohydrates and derivatives are herein presented as they are relevant to the synthetic carbohydrate community. Previously reviewed protocols for the installation of R_F groups onto carbohydrates and derivatives will be succinctly summarized in the light of the new achievements. Fluoroalkyl-substituted iminosugars, on the other hand, are also interesting glycomimetic derivatives with prominent roles as glycosidases and glycosyltransferases inhibitors, as has recently been demonstrated. Also, they positively contribute to the study of sugar-protein interactions and enzyme mechanisms. New advances in the syntheses of fluoroalkyl-substituted iminosugars will also be presented here.

Evaluation of surface active and antimicrobial properties of alkyl D-lyxosides and alkyl L-rhamnosides as green surfactants

The use of carbohydrates, as a part of surface-active compounds, has been studied due to their biodegradability and nontoxic profile. A series of alkyl glycosides containing d-lyxose and l-rhamnose with alkyl chains of 8-12 carbon atoms were investigated. The effects of structural variations on their physico-chemical and biological properties have been evaluated for a detailed understanding of their properties. Alkyl glycosides were tested on their toxicity against bacterial cells of the genus Pseudomonas (MTT assay), microbiological adhesion to hydrocarbons (MATH assay), cell surface hydrophobicity (Congo red assay), cell membrane permeability (crystal violet assay), and bacterial biofilm formation. Furthermore, their antifungal activity against two pathogenic microorganisms Candida albicans and Aspergillus niger was investigated using the disc diffusion method. Toxicological studies revealed that compounds could reduce the metabolic activity of bacterial cells only moderately but they increased the hydrophobicity of cell surface in Pseudomonas strains. In addition, alkyl glycosides changed the permeability of the cell membranes to the level of 30-40% for this strain. The compounds with an even number of carbon atoms in their alkyl chain promoted stronger bacterial biofilm formation on the glass surface. All studied derivatives demonstrated very strong antifungal activity against fungus A. niger but very small effect against C. albicans. Overall, the results showed that long-chain alkyl glycosides could be considered as inexpensive, biocompatible, nontoxic agents, and serve for the surface design to avoid bacterial adhesion as an alternative solution to antibiotic treatment.

In vitro evaluation of immunobiological activity of simple mannolipids

Immunomodulation, cytotoxicity and anti-cancer activity of selected amphiphilic non-ionic (thio)alkyl α-D-mannosides (with aglycone of C6-C12) were investigated in vitro in human cervix epitheloid carcinoma cell line HeLa, murine melanoma cancer cells B16, murine lymphocytic leukemia cell line L1210, murine fibroblast cell line NIH 3 T3 and murine macrophage cell line RAW 264.7. Toxicological studies revealed structure-dependent immunobiological effectivity based on a tight interaction with relevant cells. The results demonstrated diverse immunomodulation of macrophage cell-line RAW264.7 proliferation and production of Th1 and Th2 cytokines, and induction of pro-inflammatory interleukins IL-1α, TNFα, IL-6, IL-12 and IL-17 and anti-inflammatory IL-10 following (thio)alkyl α-D-mannosides 24 and 48 h exposure. Direct application of alkyl mannosides MOC10 and MOC12 and their thio analogues MSC10 and MSC12 in reconstructed human EpiDerm™ and MOC12 and MSC12 in EpiOcular™ model assays for dermal and ocular irritation together with quantification of human proinflammatory cytokines IL-1α, TNFα, IL-6 and IL-8 culture media release was used to ascertain toxicological safety.

Biodegradability and Toxicity of Cellobiosides and Melibiosides

In 2014, almost 16 million tons of surfactants were used globally for cleaning and industrial applications. As a result, massive quantities disperse into environmental compartments every day. There is great market interest in developing highly biodegradable, less-toxic, and renewable alternatives to currently used petroleum-based surfactants. Glycolipid surfactants, composed of a sugar head-group and lipid tail, are effective surfactants and emulsifiers with a high tolerance to electrolytes and are easily tailored to address specific needs. The green synthesis and surfactant characteristics of a suite of cellobiosides and melibiosides were recently described. The biodegradability and toxicity of 1°-alkyl-O-cellobiosides, 2°-alkyl-O-cellobiosides, and 1°-alkyl-O-melibiosides with straight-chain alkyl tails of 8, 10, and 12 are reported in this study. Biodegradability was assessed by quantifying mineralization (CO₂ evolution). All of the glycosides were inherently biodegradable and most were readily biodegradable according to OECD and EPA definitions. The Microtox acute toxicity assay showed both chain length and head group had significant effects on toxicity, but most of the molecules were practically non-toxic according to EPA definitions with EC₅₀ values > 100 mg L^-1. Cytotoxicity to human lung (H1299) and keratinocyte cell lines (HaCaT) was measured by xCELLigence and MTS assays. Cytotoxicity values were comparable to similar glycosides previously reported. IC₅₀ values were determined but, in general, exceeded surfactant concentrations that are found in the environment. These data demonstrate the promising nature of these molecules as green alternatives to petrochemical surfactants.

Preparation and characterisation of organic UV filters based on combined PHB/liposomes with natural phenolic compounds

In this study preparation and characterization of new UV-protecting systems based on liposomes/polyhydroxybutyrate (PHB) with encapsulated coffee extracts are presented. Green and roasted coffee extracts with high phenolics content, high antioxidant activity and sun protection factor (SPF) value 40-50 were used as model organic UV filters and encapsulated into liposomes and PHB-liposomes. Particle size and colloid stability was observed by dynamic light scattering and zeta-potential. Toxicity of particles was tested by MTT and LDH assay on HaCaT cell line. All prepared samples showed moderate or high encapsulation efficiency. Addition of PHB up to 50 % of lecithin led to increased size and stability. As optimal addition of 20 % PHB into liposome particles was found leading to optimum size and processing of particles, to high UV-protective effect as well as to increased colloid stability and SPF value during long-term storage. Significant differences in cell viability were found in cytotoxicity studies after exposure of keratinocytes to liposomes with different PHB content. Newly fabricated PHB-liposome particles with coffee extract were not found as toxic for HaCaT cells and in LDH test up to 12 %. These particles can act as active carriers for organic sunscreen components in combination with UV-protective effect of PHB.

Anisotropic reversed micelles with fluorocarbon-hydrocarbon hybrid surfactants in supercritical CO2

Previous work (M. Sagisaka, et al. Langmuir 31 (2015) 7479-7487), showed the most effective fluorocarbon (FC) and hydrocarbon (HC) chain lengths in the hybrid surfactants FCm-HCn (sodium 1-oxo-1-[4-(perfluoroalkyl)phenyl]alkane-2-sulfonates, where m = FC length and n = HC length) were m and n = 6 and 4 for water solubilization, whereas m 6 and n 6, or m 6 and n 5, were optimal chain lengths for reversed micelle elongation in supercritical CO₂. To clarify why this difference of only a few methylene chain units is so effective at tuning the solubilizing power and reversed micelle morphology, nanostructures of water-in-CO₂ (W/CO₂) microemulsions were investigated by high-pressure small-angle neutron scattering (SANS) measurements at different water-to-surfactant molar ratios (W₀) and surfactant concentrations. By modelling SANS profiles with cylindrical and ellipsoidal form factors, the FC6-HCn/W/CO₂ microemulsions were found to increase in size with increasing W₀ and surfactant concentration. Ellipsoidal cross-sectional radii of the FC6-HC4/W/CO₂ microemulsion droplets increased linearly with W₀, and finally reached ∼39 Å and ∼78 Å at W₀ = 85 (close to the upper limit of solubilizing power). These systems appear to be the largest W/CO₂ microemulsion droplets ever reported. The aqueous domains of FC6-HC6 rod-like reversed micelles increased in size by 3.5 times on increasing surfactant concentration from 35 mM to 50 mM: at 35 mM, FC6-HC5 formed rod-like reversed micelles 5.3 times larger than FC6-HC6. Interestingly, these results suggest that hybrid HC-chains partition into the microemulsion aqueous cores with the sulfonate headgroups, or at the W/CO₂ interfaces, and so play important roles for tuning the W/CO₂ interfacial curvature. The super-efficient W/CO₂-type solubilizer FC6-HC4, and the rod-like reversed micelle forming surfactant FC6-HC5, represent the most successful cases of low fluorine content additives. These surfactants facilitate VOC-free, effective and energy-saving CO₂ solvent systems for applications such as extraction, dyeing, dry cleaning, metal-plating, enhanced oil recovery and organic/inorganic or nanomaterial synthesis.

Synthesis, Structure⁻Activity Relationships and In Vitro Toxicity Profile of Lactose-Based Fatty Acid Monoesters as Possible Drug Permeability Enhancers

Permeability enhancers are receiving increased attention arising from their ability to increase transepithelial permeability and thus, bioavailability of orally or pulmonary administered biopharmaceutics. Here we present the synthesis and the in vitro assaying of a series of lactose-based non-ionic surfactants, highlighting the relationship between their structure and biological effect. Using tensiometric measurements the critical micelle concentrations (CMCs) of the surfactants were determined and demonstrate that increasing hydrophobic chain length reduces surfactant CMC. In vitro testing on Caco-2 intestinal and Calu-3 airway epithelia revealed that cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release assays, is presented for most of the surfactants at concentrations greater than their CMCs. Further biological study demonstrates that application of cytotoxic concentrations of the surfactants is associated with depolarizing mitochondrial membrane potential, increasing nuclear membrane permeability and activation of effector caspases. It is, therefore, proposed that when applied at cytotoxic levels, the surfactants are inducing apoptosis in both cell lines tested. Importantly, through the culture of epithelial monolayers on Transwell^® supports, the surfactants demonstrate the ability to reversibly modulate transepithelial electrical resistance (TEER), and thus open tight junctions, at non-toxic concentrations, emphasizing their potential application as safe permeability enhancers in vivo.

Physico-chemical properties and cytotoxic effects of sugar-based surfactants: Impact of structural variations

Surfactants derived from the biorefinery process can present interesting surface-active properties, low cytotoxicity, high biocompatibility and biodegradability. They are therefore considered as potential sustainable substitutes to currently used petroleum-based surfactants. To better understand and anticipate their performances, structure-property relationships need to be carefully investigated. For this reason, we applied a multidisciplinary approach to systematically explore the effect of subtle structural variations on both physico-chemical properties and biological effects. Four sugar-based surfactants, each with an eight carbon alkyl chain bound to a glucose or maltose head group by an amide linkage, were synthesized and evaluated together along with two commercially available standard surfactants. Physico-chemical properties including solubility, Krafft point, surface-tension lowering and critical micellar concentration (CMC) in water and biological medium were explored. Cytotoxicity evaluation by measuring proliferation index and metabolic activity against dermal fibroblasts showed that all surfactants studied may induce cell death at low concentrations (below their CMC). Results revealed significant differences in both physico-chemical properties and cytotoxic effects depending on molecule structural features, such as the position of the linkage on the sugar head-group, or the orientation of the amide linkage. Furthermore, the cytotoxic response increased with the reduction of surfactant CMC. This study underscores the relevance of a methodical and multidisciplinary approach that enables the consideration of surfactant solution properties when applied to biological materials. Overall, our results will contribute to a better understanding of the concomitant impact of surfactant structure at physico-chemical and biological levels.

Hemolysis by surfactants--A review

An overview of the use of surfactants for erythrocyte lysis and their cell membrane action mechanisms is given. Erythrocyte membrane characteristics and its association with the cell cytoskeleton are presented in order to complete understanding of the erythrocyte membrane distortion. Cell homeostasis disturbances caused by surfactants might induce changes starting from shape modification to cell lysis. Two main mechanisms are hypothesized in literature which are osmotic lysis and lysis by solubilization even if the boundary between them is not clearly defined. Another specific mechanism based on the formation of membrane pores is suggested in the particular case of saponins. The lytic potency of a surfactant is related to its affinity for the membrane and the modification of the lipid membrane curvature. This is to be related to the surfactant shape defined by its hydrophobic and hydrophilic moieties but also by experimental conditions. As a consequence, prediction of the hemolytic potency of a given surfactant is challenging. Several studies are focused on the relation between surfactant erythrolytic potency and their physico-chemical parameters such as the critical micellar concentration (CMC), the hydrophile-lipophile balance (HLB), the surfactant membrane/water partition coefficient (K) or the packing parameter (P). The CMC is one of the most important factors considered even if a lytic activity cut-off effect points out that the only consideration of CMC not enough predictive. The relation K.CMC must be considered in addition to the CMC to predict the surfactant lytic capacity within the same family of non ionic surfactant. Those surfactant structure/lytic activity studies demonstrate the requirement to take into account a combination of physico-chemical parameters to understand and foresee surfactant lytic potency.

Antiviral activities of 2,6-diaminopurine-based acyclic nucleoside phosphonates against herpesviruses: In vitro study results with pseudorabies virus (PrV, SuHV-1)

Pseudorabies virus (PrV), a causative agent of Aujeszky's disease, is deadly to most mammals with the exception of higher primates and men. This disease causes serious economic loses among farm animals, especially pigs, yet many European countries are today claimed to be Aujeszky's disease free because of the discovery of an efficient vaccination for pigs. In reality, the virus is still present in wild boar. Current vaccines are neither suitable for dogs nor are there anti-PrV drugs approved for veterinary use. Therefore, the disease still represents a high threat, particularly for expensive hunting dogs that can come into close contact with infected boars. Here we report on the anti-PrV activities of a series of synthetic diaminopurine-based acyclic nucleoside phosphonate (DAP-ANP) analogues. Initially, all synthetic DAP-ANPs under investigation are shown to exhibit minimal cytotoxicity by MTT and XTT tests (1-100μM range). Thereafter in vitro infection models are established using PrV virus SuHV-1, optimized on PK-15 and RK-13 cell lines. Out of the six DAP-ANP analogues tested, analogue VI functionalized with a cyclopropyl group on the 6-amino position of the purine ring proves the most effective antiviral DAP-ANP analogue against PrV infection, aided by sufficient hydrophobic character to enhance bioavailability to its cellular target viral DNA-polymerase. Four other DAP-ANP analogues with functional groups introduced to the C2'position are shown ineffective against PrV infection, even with favourable hydrophobic properties. Cidofovir(®), a drug approved against various herpesvirus infections, is found to exert only low activity against PrV in these same in vitro models.

Water-soluble lipophilic MR contrast agents for cell membrane labeling

Long-term cell tracking using MR imaging necessitates the development of contrast agents that both label and are retained by cells. One promising strategy for long-term cell labeling is the development of lipophilic Gd(III)-based contrast agents that anchor into the cell membrane. We have previously reported the efficacy of monomeric and multimeric lipophilic agents and showed that the monomeric agents have improved labeling and contrast enhancement of cell populations. Here, we report on the synthesis, characterization, and in vitro testing of a series of monomeric lipophilic contrast agents with varied alkyl chain compositions. We show that these agents disperse in water, localize to the cell membrane, and label HeLa and MCF7 cells effectively. Additionally, these agents have up to tenfold improved retention in cells compared to clinically available ProHance(®).

Cytotoxic activity of triazole-containing alkyl β-D-glucopyranosides on a human T-cell leukemia cell line

BACKGROUND

Simple glycoside surfactants represent a class of chemicals that are produced from renewable raw materials. They are considered to be environmentally safe and, therefore, are increasingly used as pharmaceuticals, detergents, and personal care products. Although they display low to moderate toxicity in cells in culture, the underlying mechanisms of surfactant-mediated cytotoxicity are poorly investigated.

RESULTS

We synthesized a series of triazole-linked (fluoro)alkyl β-glucopyranosides using the copper-catalyzed azide-alkyne reaction, one of many popular "click" reactions that enable efficient preparation of structurally diverse compounds, and investigate the toxicity of this novel class of surfactant in the Jurkat cell line. Similar to other carbohydrate surfactants, the cytotoxicity of the triazole-linked alkyl β-glucopyranosides was low, with IC50 values decreasing from 1198 to 24 μM as the hydrophobic tail length increased from 8 to 16 carbons. The two alkyl β-glucopyranosides with the longest hydrophobic tails caused apoptosis by mechanisms involving mitochondrial depolarization and caspase-3 activation.

CONCLUSIONS

Triazole-linked, glucose-based surfactants 4a-g and other carbohydrate surfactants may cause apoptosis, and not necrosis, at low micromolar concentrations via induction of the intrinsic apoptotic cascade; however, additional studies are needed to fully explore the molecular mechanisms of their toxicity. Graphical AbstractTriazole-linked, glucose-based surfactants cause apoptosis, and not necrosis, at low micromolar concentrations via induction of the intrinsic apoptotic cascade.

Synthesis, surface properties, and biocompatibility of 1,2,3-triazole-containing alkyl β-D-xylopyranoside surfactants

We are interested in the development of surfactants derived from hemicellulosic biomass, as they are potential components in pharmaceuticals, personal care products, and other detergents. Such surfactants should exhibit low toxicity in mammalian cells. In this study we synthesized a series of alkyl or fluoroalkyl β-xylopyranosides from azides and an alkyne using the copper-catalyzed azide-alkyne (CuAAC) 'click' reaction in 4 steps from xylose. The purified products were evaluated for both their surfactant properties, and for their biocompatibility. Unlike other carbohydrate-based surfactants, liquid-crystalline behavior was not observed by differential scanning calorimetry. The triazole-containing β-xylopyranosides with short (6 carbons) and long (>12 carbons) chains exhibited no toxicity at concentrations ranging from 1 to 1000 μM. Triazole-containing β-xylopyranosides with 8, 10, or 12 carbons caused toxicity via apoptosis, with CC50 values ranging from 26-890 μM. The two longest chain compounds did form stable monolayers at the air-water interface over a range of temperatures, although a brief transition to an the unstable monolayer was observed.

A novel type of highly effective nonionic gemini alkyl O-glucoside surfactants: a versatile strategy of design

A novel type of highly effective gemini alkyl glucosides has been rationally designed and synthesized. The gemini surfactants have been readily prepared by glycosylation of the gemini alkyl chains that are synthesized with regioselective ring-opening of ethylene glycol epoxides by the alkyl alcohols. The new gemini alkyl glucosides exhibit significantly better surface activity than the known results. Then rheological, DLS, and TEM studies have revealed the intriguing self-assembly behavior of the novel gemini surfactants. This study has proved the effectiveness of the design of gemini alkyl glucosides which is modular, extendable, and synthetically simple. The new gemini surfactants have great potential as nano carriers in drug and gene delivery.

Fluorous iminoalditols act as effective pharmacological chaperones against gene products from GLB₁ alleles causing GM1-gangliosidosis and Morquio B disease

Unlike replacement therapy by infusion of exogenous recombinant lysosomal enzymes, pharmacological chaperones aim at a gain of function of endogenous gene products. Deficits resulting from missense mutations may become treatable by small, competitive inhibitors binding to the catalytical site and thus correcting the erroneous conformation of mutant enzymes. This may prevent their premature degradation and normalize intracellular trafficking as well as biological half-life. A major limitation currently arises from the huge number of individual missense mutations and the lack of knowledge on the structural requirements for specific interaction with mutant protein domains. Our previous work on mutations of the β-galactosidase (β-gal) gene, causing GM1 gangliosidosis (GM1) and Morquio B disease (MBD), respectively, characterized clinical phenotypes as well as biosynthesis, intracellular transport and subcellular localization of mutants. We recently identified an effective chaperone, DL-HexDGJ (Methyl 6-{[N(2)-(dansyl)-N(6)-(1,5-dideoxy-D-galactitol-1,5-diyl)- L-lysyl]amino} hexanoate), among a series of N-modified 1-deoxygalactonojirimycin derivatives carrying a dansyl group in its N-acyl moiety. Using novel and flexible synthetic routes, we now report on the effects of two oligofluoroalkyl-derivatives of 1-deoxygalactonojirimycin, Ph(TFM)(2)OHex-DGJ (N-(α,α-di-trifluoromethyl) benzyloxyhexyl-1,5-dideoxy-1,5-imino-D: -galactitol) and (TFM)(3)OHex-DGJ (N-(Nonafluoro-tert-butyloxy)hexyl-1,5-dideoxy-1,5-imino-D: -galactitol) on the β-gal activity of GM1 and MBD fibroblasts. Both compounds are competitive inhibitors and increase the residual enzyme activities up to tenfold over base line activity in GM1 fibroblasts with chaperone-sensitive mutations. Western blots showed that this was due to a normalization of protein transport and intralysosomal maturation. The fact that the novel compounds were effective at very low concentrations (0.5-10 μM) in the cell culture medium as well as their novel chemical character suggest future testing in animal models. This may contribute to new aspects for efficient and personalized small molecule treatment of lysosomal storage diseases.

Synthesis, thermal properties, and cytotoxicity evaluation of hydrocarbon and fluorocarbon alkyl β-D-xylopyranoside surfactants

Alkyl β-d-xylopyranosides are highly surface active, biodegradable surfactants that can be prepared from hemicelluloses and are of interest for use as pharmaceuticals, detergents, agrochemicals, and personal care products. To gain further insights into their structure-property and structure-activity relationships, the present study synthesized a series of hydrocarbon (-C(6)H(13) to -C(16)H(33)) and fluorocarbon (-(CH(2))(2)C(6)F(13)) alkyl β-d-xylopyranosides in four steps from d-xylose by acylation or benzoylation, bromination, Koenigs-Knorr reaction, and hydrolysis, with the benzoyl protecting group giving better yields compared to the acyl group in the Koenigs-Knorr reaction. All alkyl β-d-xylopyranosides formed thermotropic liquid crystals. The phase transition of the solid crystalline phase to a liquid crystalline phase increased linearly with the length of the hydrophobic tail. The clearing points were near constant for alkyl β-d-xylopyranosides with a hydrophobic tail ⩾8, but occurred at a significantly lower temperature for hexyl β-d-xylopyranoside. Short and long-chain alkyl β-d-xylopyranosides displayed no cytotoxicity at concentration below their aqueous solubility limit. Hydrocarbon and fluorocarbon alkyl β-d-xylopyranosides with intermediate chain length displayed some toxicity at millimolar concentrations due to apoptosis.

Effect of solvent on absorption and fluorescence spectra of a typical fluorinated azo dye for its acidic and basic structures

The effect of 15 polar solvents on absorption and fluorescence energies of a typical fluorinated azo dye, 4-(2,3,5,6-tetrafluoro-pyridin-4-yl azo)-phenol, was reported for its acidic, MH, and basic, M, structures. For MH, the absorption energy is described on the basis of multi-linear equation with Taft's π* (solvent polarity) and β (hydrogen bond acceptor) parameters while the fluorescence energy varies rectilinearly with free energy of transferring the proton to the surrounding solvent, ΔG(t)°. For M, the hydrogen bonding donor ability of protic solvent, α, is a predominant factor which affects the absorption energy while in aprotic solvents, the absorption energy correlates linearly with Kirkwood function. As the ability of the solvent for hydrogen bonding increases, the absorption band width will increase in parallel with the transition energy.

Biology of fluoro-organic compounds

Investigations on diverse aspects of fluoro-organic compounds have rapidly increased during the past decades. Because natural sources of fluoro-organic compounds are extremely rare, the industrial synthesis of fluorinated organic compounds and production of fluorinated natural product derivatives have greatly expanded in recent years because of their increasing importance in the agrochemical and pharmaceutical industries. Due to structural complexity or instability, synthetic modification is often not possible, and various biofluorination strategies have been developed in recent years for applications in the anti-cancer, anti-viral and anti-infection fields. Despite the industrial importance of fluorinated compounds, there have been serious concerns worldwide over the levels and synthetic routes of certain fluorinated organic compounds, in particular perfluorinated chemicals (PFCs). PFCs are emerging and recalcitrant pollutants which are widely distributed in the environment and have been detected in humans and wildlife globally. PFCs have been demonstrated to be potentially carcinogenic, adversely affect the neuroendocrine and immune systems, and produce neurotoxicity, heptatotoxicity and endocrine disrupting effects in vertebrate animals. Here, we provide an overview of recent advances in our understanding of the biology of various fluoro-organic compounds and perspectives for new enzymes and metabolic pathways for bioremediation of these chemicals.