Polar Part Research Articles

Immunomodulatory effects of Blaps rynchopetera extract.

ABSTRACTPurpose:To explore the potential immunomodulatory effects of total extract and different polar parts from Blaps rynchopetera Fairmaire.Methods:Phagocytic activity was evaluated by neutral red assay, and the effect of the immune function was investigated by normal and immunocompromised mice models.Results: In vitro, total extract, as well as chloroform, ethyl acetate, n-butanol and water fractions could individually enhance the phagocytic ability of mouse peritoneal macrophages; in addition, chloroform and ethyl acetate fractions had an increasing tendency when combined stimulation with lipopolysaccharide (LPS). In vivo, ethyl acetate fraction (EAF) could enhance the immune organ index, increase the serum hemolysin level and peripheral blood immune cells of immunocompromised mice, while for normal mice, the effect was inconspicuous.Conclusions: Blaps rynchopetera extracts had noteworthy immunomodulatory effect, especially for individuals with immune disorders.

P-glycoprotein (ABCB1) - weak dipolar interactions provide the key to understanding allocrite recognition, binding, and transport.

P-glycoprotein (ABCB1) is the first discovered mammalian member of the large family of ATP binding cassette (ABC) transporters. It facilitates the movement of compounds (called allocrites) across membranes, using the energy of ATP binding and hydrolysis. Here, we review the thermodynamics of allocrite binding and the kinetics of ATP hydrolysis by ABCB1. In combination with our previous molecular dynamics simulations, these data lead to a new model for allocrite transport by ABCB1. In contrast to previous models, we take into account that the transporter was evolutionarily optimized to operate within a membrane, which dictates the nature of interactions. Hydrophobic interactions drive lipid-water partitioning of allocrites, the transport process's first step. Weak dipolar interactions (including hydrogen bonding, π-π stacking, and π-cation interactions) drive allocrite recognition, binding, and transport by ABCB1 within the membrane. Increasing the lateral membrane packing density reduces allocrite partitioning but enhances dipolar interactions between allocrites and ABCB1. Allocrite flopping (or reorientation of the polar part towards the extracellular aqueous phase) occurs after hydrolysis of one ATP molecule and opening of ABCB1 at the extracellular side. Rebinding of ATP re-closes the transporter at the extracellular side and expels the potentially remaining allocrite into the membrane. The high sensitivity of the steady-state ATP hydrolysis rate to the nature and number of dipolar interactions, as well as to the dielectric constant of the membrane, points to a flopping process, which occurs to a large extent at the membrane-transporter interface. The proposed unidirectional ABCB1 transport cycle, driven by weak dipolar interactions, is consistent with membrane biophysics.

Influence of interfacial, thermodynamic and hydrophobic parameters on Acid Red 57 removal by ionic micellar flocculation

ABSTRACT Most dyes are complex organic molecules that are highly resistant to degradation and may cause severe damage to live organisms and photosynthetic activities. In this respect, the aim of the present study was to assess the influence of interfacial, thermodynamic and hydrophobic parameters on Acid Red 57 removal from aqueous media by ionic micellar flocculation using surfactants sodium dodecanoate (C12), sodium tetradecanoate (C14) and sodium hexadecanoate (C16). The results demonstrate that an increase in the hydrophobic nature of the surfactant provokes different Krafft (Tkrafft) temperature and critical micelle concentration behaviors, and the greater the hydrophobicity the higher the solubilization temperature and lower the concentration needed for micelle formation. It was also found that long-chain surfactants cause an increase in the area of the polar part of the surfactant and change the micelle shape from lamellar (C12, C14) to cylindrical (C16), interfering in the solubilization capacity of the micelles. Micelle diameter determination aimed at demonstrating that the dye is solubilized inside the micelles via hydrophobic interactions. The dye removal tests showed that an increase in surfactant concentration improves process efficiency, surfactant C12 exhibiting the best dye removal indices (around 90%). Thermodynamic parameters showed that ionic micellar flocculation is exothermic and non-spontaneous.

Metformin hydrochloride entrapment in sorbitan monostearate for intestinal permeability enhancement and pharmacodynamics

Penetration enhancement of metformin hydrochloride via its molecular dispersion in sorbitan monostearate microparticles is reported. This represents basic philosophy to maximize its entrapment for maximum penetration effect. Drug dispersion in sorbitan monostearate with different theoretical drug contents (TDC) were prepared. Products showed excellent micromeritics and actual drug content (ADC) increased by increasing TDC. The partition coefficient of the drug products showed huge improvement. This indicates the drug entrapped in the polar part of sorbitan monostearate as a special image which effects on the drug release. The drug permeation profiles from the different products are overlapped with nearly equal permeation parameters. The permeation results suggested the main driving force for improving the drug paracellular pathway is its dispersion in sorbitan monostearate and is independent of ADC. Pharmacodynamic of the products showed a significant improvement than the drug alone at p ˂ 0.05. ANOVA test indicated the insignificant pharmacodynamic difference between the low, middle, and high ADC of the products. An excellent correlation founded between the drug permeation and pharmacodynamic precents. Drug permeation driving force via the paracellular pathway is its entrapment in sorbitan monostearate and independent on ADC. The technique is simple and the products had excellent micromeritics.

Decoding Multiple Biofunctions of Maca on Its Anti-allergic, Anti-inflammatory, Anti-thrombotic, and Pro-angiogenic Activities.

Four active partition layers and ten isolates, including (5R)- and (5S)-macapyrrolidone A (1a, 1b), and four new alkaloids, (5R)- and (5S)-macapyrrolidone B (2a, 2b) and macapyrrolins D, E (3, 4), were isolated from maca (Lepidium meyenii Walp.), an indigenous food plant from Peru. Derived from the n-hexane layer, the macamide-rich fraction exhibited pro-angiogenic activity on EPC and HUVEC cells. Anti-thrombotic activity was displayed by the polar part of maca extracts (n-butanol and water layers). Both 75% methanol aq. (midlower polar part) and n-hexane (low polar part) layers, which showed signs of fatty acid content, markedly inhibited superoxide and elastase release in an anti-inflammatory assay. The 75% methanol aq. layer showed strong anti-allergic activity, and macapyrrolin A (5) was found active based on β-hexosaminidase release inhibition assays and a ChemGPS-NP experiment. These valuable bioactivity results suggest that maca is a food plant with good benefits for human health.

Clotrimazole Fluidizes Phospholipid Membranes and Localizes at the Hydrophobic Part near the Polar Part of the Membrane.

Clotrimazole (1-[(2-chlorophenyl)-diphenylmethyl]-imidazole) is an azole antifungal drug belonging to the imidazole subclass that is widely used in pharmacology and that can be incorporated in membranes. We studied its interaction with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipid vesicles by using differential scanning calorimetry and found that the transition temperature decreases progressively as the concentration of clotrimazole increases. However, the temperature of completion of the transition remained constant despite the increase of clotrimazole concentration, suggesting the formation of fluid immiscibility. 1H-NMR and 1H NOESY MAS-NMR were employed to investigate the location of clotrimazole in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipid membranes. In the presence of clotrimazole, all the resonances originating from POPC were shifted upfield, but mainly those corresponding to C2 and C3 of the fatty acyl, chains suggesting that clotrimazole aromatic rings preferentially locate near these carbons. In the same way, 2D-NOESY measurements showed that the highest cross-relaxation rates between protons of clotrimazole and POPC were with those bound to the C2 and C3 carbons of the fatty acyl chains. Molecular dynamics simulations indicated that clotrimazole is located near the top of the hydrocarbon-chain phase, with the nitrogen atoms of the imidazole ring of clotrimazole being closest to the polar group of the carbonyl moiety. These results are in close agreement with the NMR and the conclusion is that clotrimazole is located near the water–lipid interface and in the upper part of the hydrophobic bilayer.

LC-HRMS/MS phytochemical profiling of Symphytum officinale L. and Anchusa ochroleuca M. Bieb. (Boraginaceae): Unveiling their multi-biological potential via an integrated approach

This study was aimed at providing a comprehensive phytochemical characterization and multi-biological assessment of Symphytum officinale L., a medicinal plant with a noteworthy traditional use, and Anchusa ochroleuca M. Bieb., a Boraginaceae species from the Romanian flora. The dichloromethane, methanol and 65 % ethanol extracts obtained from the roots and aerial parts of both plants revealed the presence of numerous phenolic acids, oxygenated fatty acids, pyrrolizidine alkaloids (PAs) and flavonoids, as assessed by LC-HRMS/MS analysis. Consistent with their higher total phenolic content, the polar aerial part extracts of S. officinale and root extracts of A. ochroleuca showed the most significant antioxidant activities, as evaluated by DPPH (173.22–216.98 mg TE/g) and ABTS (219.41–311.97 mg TE/g) radical scavenging, CUPRAC (387.18–626.40 mg TE/g), FRAP (199.36–299.86 mg TE/g) and total antioxidant capacity (2.28–2.68 mmol TE/g). Furthermore, both plants exhibited good tyrosinase (19.11–43.89 mg KAE/g) and α-glucosidase (2.45–12.54 mmol ACAE/g) inhibitory effects. The orthogonal projections to latent structures discriminant analysis (OPLS-DA) allowed the objective differentiation between the roots and aerial parts of the two investigated species based on their phytochemical and biological profiles. The partial least square (PLS) analysis showed that several individual phenolic acids, such as danshensu, rabdosiin and rosmarinic acid, significantly contributed to the antioxidant potential of both Boraginaceae species, whilst the relative levels of sucrose were positively correlated with the anti-enzymatic properties. Overall, S. officinale and A. ochroleuca could be regarded as rich sources of bioactive phytochemicals that could further lead to developing novel phyto-pharmaceutical commodities.

Alteration effect on petrophysical properties of reservoirs rocks by drilling fluid emulsifiers

Surfactants formulated into oil-based mud can adsorb to pore surfaces causing changes in rock wettability, which are widely believed to impair formation permeability when oil-based mud invades the near-wellbore region. In the present study, the effects of oil-based mud with Versawet and Versacoat surfactants, on the petrophysical properties and wettability of drilling cutting samples from sandstone reservoirs were investigated through relative permeability, wettability index, and adsorption measurements at standard conditions in a micromodel device. The X-ray analysis and flame photometer were used to characterize the drilling cuttings samples, and the functional groups of surfactants were identified by the infrared spectroscopy. Relative permeability was studied using the unsteady state method, and the wettability index was measured by the Amott method after the aging with drilling formulation for 24 to 720 h and then the adsorption behavior of surfactants using Langmuir isotherm. The results show that drilling cutting is mainly composed of quartz 71.9%. Surfactant in oil-based mud reduces permeability and causes a change in wettability to a more oil-wet state, and these effects become more pronounced as the contact period with the surfactant increases. The wettability of a reservoir rock was altered due to surfactant adsorption and the formation of a hydrophobic layer on the surface of drilling cutting samples. The adsorption and retention of polar part of the surfactants -NH2 for Versawet and -COOH for Versacoat on the silanol groups and the calcium atoms included in the structure of the reservoir rocks. They are the key interactions in the wettability alteration process.

GREEN BIOSYNTHESIZED SILVER NANOPARTICLES MEDIATED BY TRICHOSANTHES CUCUMERINA EXTRACT AND ITS BIOLOGICAL ACTIVITIES

Biosynthesized Nanoparticles especially from plants are a new research trend nowadays. In this study, green biosynthesis of silver nanoparticles (TCAgNPs) employing Trichosanthes cucumerina methanol leaf extract was realized. The antioxidant and anti-inflammatory activities of both the methanol extract of T. cucumerina and TCAgNPs were carried out and compared. Indomethacin and ascorbic acid were employed as a positive control for these activities respectively. Fourier transform infrared spectroscopy (FT-IR) scanning electron microscopy (SEM) and Ultraviolet-visible spectroscopy were employed to characterize the formation of TCAgNPs. The TCAgNPs showed absorption bands at around 340-440 nm which is a distinctive band for Ag Nanoparticles and functional groups accountable for Ag nanoparticles synthesized by plants were noticed in the FTIR. TCAgNPs were spherical in morphology as seen from the SEM images. TCAgNPs displayed better antioxidant and anti-inflammatory activities at 400 ug/ml (9.79±0.58) as compared with its polar extracts (7.74±0.58) but both the polar part (52.06±1.27) and TCAgNPs (61.72±2.54) were better in anti-inflammatory activity when compared with the positive control indomethacin (antiinflammatory) (48.30±0.23). This study revealed that AgNPs from plants can find germaneness in food, drugs, environmental sciences and drugs.

The cell membrane as the barrier in the defense against nanoxenobiotics: Zinc oxide nanoparticles interactions with native and model membrane of melanoma cells.

Currently, we are dealing with ever-increasing pollution of the environment with metal and metal oxide nanoparticles. One type of these, zinc oxide nanoparticles (ZnO-NPs), are increasingly used in areas such as cosmetology, electrical engineering, medicine, and even in the food and textile industries. As a consequence, ZnO-NPs may enter the human body in many ways. Their influence on the body is still not clear. Here, we define the mechanism of the initial toxicity of ZnO-NPs to cells based on interaction with the lipid part of the native and model cell membrane. The selected cell lines react differently to contact with nanoparticles. We found a disruption of the native membranes of B16-F0 cells and to a lesser extent of COLO 679. In turn, the membrane of COLO 679 cells was more peroxidated, and cell viability was much lower. A model of the lipid part of the membrane was created for B16-F0 cells and compared with previously published studies on immune cells. On the basis of physicochemical parameters obtained for individual lipids and a mix representing the native membrane of the tested cells, we concluded that exposure to nanoparticles resulted in a change within the model membranes (specifically with the polar parts of lipids). The greatest interaction has been noticed between ZnO-NPs and zwitterionic phospholipids (PC and PE), cholesterol, and negatively charged phosphatidylglycerol. Assessing the interactions between the membrane and nanoparticles will help to better understand the first steps of its toxicity mechanism.

Effect of Different Solvent Extracts of Amygdalus mongolica on Liver Fibrosis Rat Models Induced by Carbon Tetrachloride and Its Mechanisms

To investigate the effects and possible mechanisms of different polarity positions of Amygdalus mongolica on carbon tetrachloride to hepatic fibrosis rats. Male SD rats were divided into 7 groups with 10 in each group. The rats were divided into model group, silymarin group (0.05 g/kg), positive drug group and Amygdalus mongolica petroleum ether, ethyl acetate, n-butanol and aqueous extract group. The rats in the same group were not given carbon tetrachloride as normal control group. After 8 weeks of treatment, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activity and malondialdehyde (MDA), superoxide dismutase (SOD), hyaluronic acid (HA), laminin (LN), type Ⅲ collagen (PC-Ⅲ) and type Ⅳ collagen (Col-Ⅳ) content were measureed, and the liver index and spleen index were calculated; The contents of MDA, SOD and Hydroxyproline(HYP) and the expressions of transforming growth factor β1 protein (TGF-β1), mothers against decapentaplegic homolog 3 (Smad3) and Smad7 mRNA in liver tissues were also measured. Compared with the model group, the body mass of the rats in various polar parts of Amygdalus mongolica significantly increased (P<0.05), MDA in serum and tissues significantly decreased (P<0.05), SOD in serum significantly increased (P<0.05), and liver index of the rats in petroleum ether and water parts significantly decreased (P<0.05). The results of pathological examination showed that the liver fibrosis of the rats in each part of the drug group was significantly improved. Amygdalus mongolica petroleum ether part and n-butanol part could significantly decrease in the serum AST, ALP, HA, PC-Ⅲ content (P<0.05), HYP, TGF-β1 and Smad3 levels in the organization (P<0.05). The n-butanol position of Amygdalus mongolica could significantly reduce the serum ALT level (P<0.05). Amygdalus mongolica herbs petroleum ether, n-butanol extract has improved markedly effect to liver fibrosis, which is the preferred active site for protection of liver fibrosis and its mechanism may be through adjusting abnormal collagen synthesis and TGF-β1 / Smad signaling pathways to work.

CALCULATION OF HYDROPHILIC-LIPOPHILIC BALANCE FOR THE SYSTEM OF 2,3-SUBSTITUTED-5,6-DIHYDRO-3H-[1,3]THIAZOLO[3,2-b][1,2,4]TRIAZOL-7-IUM

Cationic surfactants are widely used in industry, medicine, and in studies of a number of physicochemical processes. Analysis of the literature data indicates the high biological activity of cationic surfactants, particularly antimicrobial, antifungal, and in general biocidal. Currently, QSPR methods are increasingly used; they allow the prediction of properties based on the compound's molecular structure. One of the important parameters of cationic surfactants is the ratio of polar (positively charged "head") and non-polar (long hydrocarbon "tail") parts of their molecules. This ratio is called hydrophilic-lipophilic balance (HLB). In 1949, Griffin and Davis developed HLB scales of colloidal surfactants, according to which the HLB parameter can take values in the range from 1 (the substance is insoluble in water but soluble in nonpolar liquids) to 40 (the substance is soluble in water and insoluble in nonpolar liquids) conventional units. Given the complexity of the experimental determination of HLB, mathematical additive models for its calculation were developed.&#x0D; In our previous studies, methods for the synthesis of cationic 1,2,4-triazolium systems, including cationic surfactants based on 1,3-thiazolo-1,2,4-triazole condensed nucleus, were developed. Thus, 2,3-substituted-5,6-dihydro-3H-[1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium were selected as model objects in this study.&#x0D; The construction of model compounds was performed in the Avogadro program with subsequent optimization of the geometry using the force field MMFF94. The HLB index was calculated by three methods: Griffin, Davis, and the ratio of polar and nonpolar areas on the isosurface of the molecule using the software package Vega ZZ.&#x0D; Simple approach for calculating HLB based on the number of carbon atoms in long alkyl substituents have been established. HLB values are the largest when calculating the ratio of polar and non-polar parts of the molecule. The calculated values of HLB vary in a wide range, which allows referring the investigated systems to emulsifiers "oil/water" (for short alkyl chains C1–C4), wetting agents (for short alkyl chains C1–C5), emulsifiers "water/oil" (for alkyl chains C5–C20), antifoams (for alkyl chains C18–C20).

Wet granulation end point prediction using dimensionless numbers in a mixer torque rheometer: Relationship between capillary and Weber numbers and the optimal wet mass consistency

The optimal wet mass consistency during wet granulation is often determined using the hand squeezing test. In this study, torque values recorded inside the wet mass were measured using a mixer torque rheometer (MTR) via multiple additions of liquid. The main objective of this work was to predict the optimal wet mass consistency of pharmaceutical powders using the modified capillary (Ca∗) and Weber (We∗) dimensionless numbers. The results show that the optimal wet mass consistency versus Ca∗ (or We∗) can be fitted with a power–law function, whereas the improved capillary number Ca′ proposed in this work gives different relationships and behaviors depending on the spreadability and wettability of the blend. The wettability was obtained by measuring the contact angle between the liquids and the pharmaceutical powders. The surface free energy and the polar and dispersive parts of a liquid’s surface energy were obtained from Young’s equation and the Owens–Wendt–Rabel–Kaelble (OWRK) model. This study demonstrated the importance of the interfacial energy σb-s and the pore radius, Rpore in the establishment of a dimensionless number, Ca∗, that can satisfactorily predict with an R2 of 0.80, the optimal wet mass consistency of pharmaceutical powders measured by the MTR.

Interactions of primaquine and chloroquine with PEGylated\ufeff phosphatidylcholine liposomes

This study aimed to analyze the interaction of primaquine (PQ), chloroquine (CQ), and liposomes to support the design of optimal liposomal delivery for hepatic stage malaria infectious disease. The liposomes were composed of hydrogenated soybean phosphatidylcholine, cholesterol, and distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy[polyethyleneglycol]-2000), prepared by thin film method, then evaluated for physicochemical and spectrospic characteristics. The calcein release was further evaluated to determine the effect of drug co-loading on liposomal membrane integrity. The results showed that loading PQ and CQ into liposomes produced changes in the infrared spectra of the diester phosphate and carbonyl ester located in the polar part of the phospholipid, in addition to the alkyl group (CH2) in the nonpolar portion. Moreover, the thermogram revealed the loss of the endothermic peak of liposomes dually loaded with PQ and CQ at 186.6 °C, which is identical to that of the phospholipid. However, no crystallinity changes were detected through powder X-ray diffraction analysis. Moreover, PQ, with either single or dual loading, produced the higher calcein release profiles from the liposomes than that of CQ. The dual loading of PQ and CQ tends to interact with the polar head group of the phosphatidylcholine bilayer membrane resulted in an increase in water permeability of the liposomes.

Explore antioxidant quality markers of Hippophae tibetana based on "dry-method + wet-method" technology

The cross combination of dry-method(network pharmacology analysis) and wet-method(high-resolution mass spectro-metry with antioxidation experiment) was used to predict antioxidant quality markers(Q-markers) of Hippophae tibetana. Ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry(UPLC-Q-Exactive Orbitrap-MS) was developed to rapidly separate and identify the chemical constituents in H. tibetana. Then in DPPH free radicals and superoxide anion scavenging experiment, the antioxidant activity of the four different polar parts with extracts of petroleumether, ethyl acetate, n-butanol and water was evaluated. Network pharmacology method was used for functional enrichment and pathway analysis to screen antioxidant-related components and preliminarily explain the mechanism of action. On this basis, multi-source information was integrated to predict the antioxidant Q-markers. The results showed that 51 components in H. tibetana were identified, including 18 flavonoids, 14 terpenoids, 6 alkaloids, 4 coumarins and phenylpropanoids, 3 volatile components and 2 polyphenols. The antioxidant capacity of different fractions: ethyl acetate &gt; n-butanol &gt; water &gt; petroleum ether. The medicine mainly acted on PI3 K-Akt and FoxO signaling pathways to perform antioxidant effects through flavonoids such as quercetin, luteolin and kaempferol. According to the results of dry-method and wet-method, quercetin, luteolin and kaempferol, the representatives of poly-hydroxy flavone, may be the antioxidant Q-markers of H. tibetana. In this study, with the antioxidant Q-markers of H. tibetana as an example, an investigation model of predicting Q-marker was discussed based on the ternary system of composition, function and informatics, providing a scientific basis for the establishment of quality evaluation standards for H. tibetana.

Influence of Surface Characteristics of Different Implant Abutment Materials on Growth of Porphyromonas Gingivalis

The purpose of the present study was to determine the surface physicochemical properties of polished implant abutment materials and to investigate their relationship with the growth of Porphyromonas gingivalis in vitro. Four groups of the most popular prosthetic materials were used in this study: titanium alloy (Ti), yttria-stabilized zirconium oxide (3Y-TZP), polyether ether ketone (PEEK) composite, and poly(methyl methacrylate) (PMMA). The plate shape specimens (10 × 10 × 0.5 mm) were polished by applying sequential mechanical polishing. Measurements of water contact angle (WCA), surface free energy (SFE) and roughness were performed. Also, the growth of P.gingivalis was measured via counting colony-forming units to milliliter (CFUs/mL). The WCA means were significantly different among all groups, and the highest hydrophilicity was observed on the PEEK, whereas the lowest on PMMA surface. All measured surfaces had similarly low SFE values, but Ti, 3Y-TZP, and PEEK demonstrated more expressed polar parts. All means of roughness were beyond the micro-level and were lower than 0.2 µm. The highest CFUs/mL was assessed on the PMMA and it was significantly different from others, whereas the lowest was on 3Y-TZP. The surface roughness had a significant impact on CFUs/mL growth.

Incorporation of simvastatin into lipid membranes: Why deliver a statin in form of inclusion complex with hydrophilic cyclodextrin

In this work, the effects of simvastatin (SIM), (2-hydroxypropyl)-β-cyclodextrin (HPβCD) and their complex (SIM:HPβCD) on the structure and properties of lipid membranes were investigated for the first time by Langmuir technique combined with PM-IRRAS spectroscopy. An improved understanding of the differences of the interactions between free SIM, and SIM in the form of an inclusion complex with HPβCD with the lipid membrane will improve the development of preparation methods for in vivo applications. Monolayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), cholesterol (Chol) and their mixture DMPC:Chol (7:3) served as simple models of one leaflet of the cell membrane. The penetration of well-organized lipid layers by simvastatin lead to their fluidization but the extent of this unwanted effect was smaller when the drug was delivered in the form of the SIM:HPβCD complex. Surface pressure vs. time dependencies showed that the drug encapsulated with cyclodextrin dissociated from the complex upon contact with the lipid layer and the weak interactions between the exterior polar part of the HPβCD and the polar headgroups of the lipid layer facilitated smooth incorporation of the released lipophilic drug into the membrane. At a longer time-scale, the HPβCD ligand released from the complex removed some cholesterol, but not DMPC, from the lipid layer, hence, similarly to the enzyme inhibiting action of statins – it lead to the decrease of the amount of cholesterol in the membrane. Delivery of simvastatin in the form of an inclusion complex with HPβCD is proposed as an approach improving its bioavailability in the cholesterol-lowering therapies.

Effects of 3FTx Protein Fraction from Naja ashei Venom on the Model and Native Membranes: Recognition and Implications for the Mechanisms of Toxicity.

Three-finger toxins are naturally occurring proteins in Elapidae snake venoms. Nowadays, they are gaining popularity because of their therapeutic potential. On the other hand, these proteins may cause undesirable reactions inside the body′s cells. A full assessment of the safety of Naja ashei venom components for human cell application is still unknown. The aim of the study was to determine the effect of the exogenous application of three-finger toxins on the cells of monocytes (U-937) and promyelocytes (HL-60), with particular emphasis on the modification of their membranes under the influence of various doses of 3FTx protein fraction (0–120 ng/mL). The fraction exhibiting the highest proportion of 3FTx proteins after size exclusion chromatography (SEC) separation was used in the experiments. The structural response of cell membranes was described on the basis of single-component and multi-component Langmuir monolayers that mimicked the native membranes. The results show that the mechanism of protein–lipid interactions depends on both the presence of lipid polar parts (especially zwitterionic type of lipids) and the degree of membrane saturation (the greatest-for unsaturated lipids). The biochemical indicators reflecting the tested cells (MDA, LDH, cell survival, induction of inflammation, LD50) proved the results that were obtained for the model.

Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion

Why can beetles such as the ladybird beetle Coccinella septempunctata walk vertically or upside-down on a smooth glass plane? Intermolecular and/or capillary forces mediated by a secretion fluid on the hairy footpads have commonly been considered the predominant adhesion mechanism. However, the main contribution of physical phenomena to the resulting overall adhesive force has yet to be experimentally proved, because it is difficult to quantitatively analyse the pad secretion which directly affects the adhesion mechanism. We observed beetle secretion fluid by using inverted optical microscopy and cryo-scanning electron microscopy, which showed the fluid secretion layer and revealed that the contact fluid layer between the footpad and substrate was less than 10–20 nm thick, thus indicating the possibility of contribution of intermolecular forces. If intermolecular force is the main physical phenomenon of adhesion, the force will be proportional to the work of adhesion, which can be described by the sum of the square roots of dispersive and polar parts of surface free energy. We measured adhesion forces of ladybird beetle footpads to flat, smooth substrates with known surface free energies. The adhesive force was proportional to the square-root of the dispersive component of the substrate surface free energy and was not affected by the polar component. Therefore, intermolecular forces are the main adhesive component of the overall adhesion force of the ladybird beetle. The footpads adhere more strongly to surfaces with higher dispersive components, such as wax-covered plant leaves found in the natural habitat of ladybird beetles. Based on the present findings, we assume ladybird beetles have developed this improved performance as an adaptation to the variety of plant species in its habitat.

Lignin-containing adhesion enhancer for wood-plastic composites

A lignin-containing adhesion enhancer, a water-soluble polyelectrolyte complex (LPEC) composed of soda hardwood lignin (HASL) and polyethylenimine (PEI), and the effect of the treatment of hydrolyzed and ammoxidized aspen sawdust with the LPEC nanoparticles were studied relative to the properties of wood-plastic composites (WPCs) based on recycled polypropylene (rPP). The presence of the excess of free amine groups and salt bonds between PEI and soda lignin, forming hydrophobic sites in the LPEC structure, caused the enhanced surface activity of the LPEC. The treatment with the LPEC nanoparticles increased the content of the fixed nitrogen in the modified sawdust samples and was accompanied by decreasing their water sorption and increasing contact angles that favored the decrease in the polar part of their surface free energy. The decreasing wetting ability enhanced the mechanical and water sorption properties of the obtained WPC samples. The improvement of the interfacial adhesion between the nitrogen-containing groups of the treated sawdust and the oxygen-containing groups of rPP was explained by the formation of both covalent and physicochemical bonds.