Soybean Phosphatidylcholine Liposomes Research Articles

Selective Cellular Uptake and Cytotoxicity of Curcumin-encapsulated SPC and HSPC Liposome Nanoparticles on Human Bladder Cancer Cells.

Curcumin is a main bioactive constituent of turmeric (Curcuma longa L.) with pleiotropic health beneficial effects. However, poor bioavailability is the major barrier to the efficient pharmacological effects of curcumin in humans. The present study aimed to develop liposome formulations based on soybean phosphatidylcholine (SPC) and hydrogenated SPC (HSPC) to enhance the bioavailability of curcumin in bladder cancer cells. Curcumin was encapsulated in HSPC and SPC liposome nanoparticles using the solvent evaporation method. Physical properties, encapsulation efficiency (%), stability, and in vitro drug release of the prepared liposome formulations have been evaluated. The cellular uptake and cytotoxicity of curcumin-encapsulated nanoliposomes on bladder carcinoma HTB9 cell line and normal fibroblast L929 cell line were studied. DNA fragmentation, apoptosis, and genotoxicity assessments have been carried out to determine the molecular mechanisms underlying the cytotoxic effects of liposomal curcumin formulations on bladder cancer cells. The results indicated that curcumin could be efficiently encapsulated in the HSPC and SPC liposome formulations. The liposomal curcumin formulations have shown shelf-life stability for 14 weeks at 4°C. The accelerated stability testing showed that curcumin encapsulated in nanoliposomes was significantly (p < 0.001) more stable than free curcumin at various pH degrees ranging from alkaline to acidic pH. The in vitro drug release study showed curcumin to be sustainably released from the liposome nanoparticles. Of note, SPC and HSPC nanoliposome formulations significantly increased the cellular uptake and cytotoxicity of curcumin on bladder cancer HTB9 cells. Mechanistically, liposomal curcumin was found to exert a selective inhibitory effect on the viability of cancer cells by inducing apoptosis and DNA damage. In conclusion, SPC and HSPC liposome nanoparticles can significantly increase the stability and bioavailability of curcumin, which are important for improving its pharmacological effect.

Effect of phospholipids on membrane characteristics and storage stability of liposomes

The membrane characteristics and storage stability of liposomes prepared by different phospholipids were investigated, including soybean phosphatidylcholine (SPC), egg yolk phosphatidylcholine (EPC) and hydrogenated soy phosphatidylcholine (HSPC). The mean vesicle size of HSPC liposomes was 437.8 nm, while the size of SPC and EPC liposomes were 112.3 and 121.3 nm, respectively. The AFM and TEM images demonstrated that SPC and EPC liposomes exhibited a more uniform distribution and greater membrane fluidity. The liposomes demonstrated different crystallization behavior and phase transition temperatures by XRD and DSC, respectively. Due to high saturated fatty acids content of HSPC, these liposomes displayed a tighter membrane packing as evident by FTIR and Raman spectra. The membrane hydrophobicity and micropolarity decreased with storage time. During storage, HSPC liposomes maintained a more compact membrane structure. HSPC liposomes were the most stable during storage as evident by significantly lower levels of lipid hydrolysis and oxidation.

Innovative food ingredients based on the milk protein–chitosan complex particles for the fortification of food with essential lipids

The aim of this work was to elucidate the influence of both the structural features of milk proteins [whey proteins (WPI) and sodium caseinate (SC)] and the character of their electrostatic associative interactions with chitosan (CHIT) on the structure, thermodynamic parameters and functionality of their complexes with essential lipids. These lipids included soybean phosphatidylcholine liposomes (PC), rich in omega-6 linoleic (LA) polyunsaturated fatty acid (PUFA), and long chain omega-3 PUFAs (eicosapentaenoic and docosahexaenoic acids) from fish oil (FO) to their equal weight ratio with LA. A laser light scattering method was used in static, dynamic and electrophoretic modes to characterise the structure and thermodynamic parameters of the supramolecular complexes in an aqueous medium. The functionality of the supramolecular complexes (WPI−CHIT−PC−FO and SC−CHIT−PC−FO) was considered from the point of view of their solubility in an aqueous medium and protective abilities against oxidation of the essential lipids encapsulated in them.

Lipid-coated membranes as skin surrogates for permeability assessment

There is a growing interest in developing in vitro skin models, particularly in the fields of skin care and drug delivery regarding optimization of topical drug formulations. The ban of animal experiments for cosmetic products testing has led to the development of alternative in vitro methods. The aim of this study was to develop and characterize simplified, cell-free, lipid-coated membrane models, exploring the usefulness and the potential application of these membranes in comparison to commercial synthetic membrane and to porcine skin. In these model membranes, lipids are deposited onto a polycarbonate membrane to create lipid-rich coated membranes. Two types of lipid-coated membranes were explored depending on the type of lipids used. In one type (phospholipidic), membranes were prepared depositing soybean phosphatidylcholine liposomes and in the other type (non-phospholipidic), major components of the stratum corneum lipid matrix were used to coat the polycarbonate membrane. Coating process was performed using drying and centrifugation steps. Under infinite dose conditions, and caffeine as permeant, high permeation correlation between developed membranes and pig skin was obtained, and similar permeation pro-files were obtained through phospholipidic and non-phospholipidic membranes. This study demonstrated the potential of the developed membranes to conduct permeation studies using Franz-type diffusion cells, and the simplication process to produce lipid-coated membranes.

Anti-Inflammatory Properties, Bioaccessibility and Intestinal Absorption of Sea Fennel (Crithmum maritimum) Extract Encapsulated in Soy Phosphatidylcholine Liposomes.

A sea fennel (Crithmum maritimum) aqueous extract was prepared and loaded into soybean phosphatidylcholine liposomes. Both the free extract (FE), and the empty (L) and loaded (L-FE) liposomes were shown to be non-cytotoxic to THP-1 and Caco-2 cells. The anti-inflammatory effect was tested on THP-1 cells differentiated into macrophages. FE showed anti-inflammatory activity, revealed by the induced secretion of IL-10 cytokines in macrophages that were subsequently stimulated with LPS. Also, a decrease in TNF-α production by L was observed, evidencing that liposomes reduced the pro-inflammatory mediators’ secretion. The liposomes (L) showed protective anti-inflammatory activity and also were able to downregulate the inflammation. Furthermore, L-FE were also found to downregulate the inflammation response, as they were able to decrease TNF-α secretion in macrophages previously exposed to LPS. The simulated in vitro gastrointestinal digestion (GID) of FE diminished the chlorogenic acid content (the main polyphenolic compound of the extract) by 40%, while in L-FE, the amount of this phenolic compound increased with respect to the undigested liposomes. The amount of bioaccessible chlorogenic, however, was similar for FE and L-FE. The percentage of chlorogenic acid absorbed through a Caco-2 cell monolayer after 3 h of incubation, was significantly similar for the extract and the liposomes (~1.5%), without finding significant differences once the extract and liposomes were digested.

Ascorbyl palmitate effects on the stability of curcumin-loaded soybean phosphatidylcholine liposomes

The effect of ascorbyl palmitate (AP) on the physical stability of soy phosphatidylcholine (SPC) liposomes and the retention rate of curcumin loaded into SPC liposomes enriched with different concentrations of AP was studied. Results showed that the transmittance, stability coefficient and particle size of liposomes were all influenced by the addition of AP. The highest stability of AP-stabilized liposomes was achieved when the mass ratio of SPC to AP was at 50:5 by increasing the surface charge, as indicated by an increase in ζ-potential from −15.1 mV (pure liposome) to −35.4 mV (AP-enriched SPC). Beyond this ratio, excessive AP addition was unfavorable to the stability of liposomes. Also at this 10% ratio, small angle X-ray scattering and differential scanning calorimetry results showed the strongest interaction between AP and the SPC liposomes, with the altering of the bilayer structure and the main phase transition temperature. Atomic force microscopy results showed that the addition of AP did not obviously change the vesicle microstructure but increased the vesicle height and contact angle. When curcumin was loaded into AP-enriched liposomes as a model bioactive, the best storage stability was observed in the liposome formulation with 10% added AP, which correlated well with the physical stability of the system. These results open up the possibility of AP-modified liposomes being developed as a multifunctional formulation for encapsulating and delivering nutraceuticals.

Effects of Phytosterol Butyrate Ester on the Characteristics of Soybean Phosphatidylcholine Liposomes.

The nutritional and structural properties of phytosterols (PS)/phytosterol esters (PEs) facilitate their use as substitutes for cholesterol in liposome encapsulation systems designed for oral drugs and health products. The purpose of this study was to determine the effect of phytosterol butyrate ester (PBE) on the properties of liposomes. PBE was encapsulated within liposomes (approximately 60 nm) prepared using soybean phosphatidylcholine using the thin-film hydration method. There was no significant change in the average particle diameter and zeta potential of these liposomal vesicles corresponding to the increasing amounts of encapsulated PBE. The incorporation of PBE increased the polydispersity index (PDI) independent of concentration. Additionally, we observed that the storage stability of PBE liposomes with uniform particle size and approximately spherical shape vesicle was better at low concentration. The results of Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy showed that PBE was positioned at the water interface, which increased the order of hydrophobic alkyl chains in the lipid membranes. The incorporation of PBE led to an increase in the trans conformation of hydrophobic alkyl chain and consequently, the thermal stability of liposomes, which was confirmed by differential scanning calorimetry (DSC). The results of powder X-ray diffraction (XRD) analysis confirmed that PBE was present in an amorphous form in the liposomes. Additionally, the incorporation of PBE reduced the micropolarity of the lipid membrane. Thus, when preparing liposomes using thin-film hydration, the presence of PBE affected the characteristics of liposomes.

The Effect of the Composition of a Liposomal Nanocomplex on the Antioxidant Activity of Murine Blood Plasma and Lipids of the Liver and Brain

Much attention is given to research and development of efficient systems for the delivery of essential omega-3-polyunsaturated fatty acids and other nutraceuticals to the human body with food. Nanocomplexes, which are based on soybean phosphatidylcholine liposomes with nutraceuticals included, are among the efficient delivery systems. The prolonged use of these nanocomplexes may affect the antioxidant status in various organs and tissues. In this work, thermo-initiated chemiluminescence was used to study changes in the antioxidant activity of the blood plasma, liver, and brain lipids in mice divided into six groups depending on the composition of liposomal nanocomplexes introduced into drinks substituted for water in a long-term (3 month) diet. The components of six types of liposomal nanocomplexes, except for phosphatidylcholine, in different combinations were clove essential oil, fish oil, and sodium caseinate. The results of the study showed that nanocomplexes containing liposomes made of phosphatidylcholine with the addition of fish oil and clove essential oil and encapsulated in milk protein (sodium caseinate) proved to be the most effective in increasing the antioxidant activity of the blood plasma and brain lipids in mice compared to the control.

Impact of the character of the associative interactions between chitosan and whey protein isolate on the structure, thermodynamic parameters, and functionality of their complexes with essential lipids

The aim of this work is the clarification of the impact of the character of associative interactions (covalent and non-covalent (electrostatic)) between chitosan (CHI) and whey protein isolate (WPI) on the structure, thermodynamic parameters and functionality of their complexes with essential lipids. These lipids included soybean phosphatidylcholine liposomes (PC), originally rich in omega-6 linoleic fatty acid (LA), enriched in omega-3 α-linolenic fatty acid (ALA) to an equimass ratio with LA. Differential scanning calorimetry and laser light scattering indicated that the covalent (WPI–CHI) conjugate had a greater degree of protein unfolding, a more open architecture of a random coil and a lower density compared to the same parameters of the electrostatic (WPI–CHI) complex. These structural features of the covalent conjugate contributed to the formation of the ternary (WPI–CHI) + (PC−ALA) complex particles with a higher molar mass and density as well as a more open architecture compared with the same parameters of the ternary electrostatic group. Similar properties of these ternary complexes are the following: a nanoscale size; a high aqueous solubility in the vicinity of the WPI isoelectric point (at pH = 5.1); ζ-potential ≥ +30 mV; an increase in the microviscosity of the encapsulated (PC−ALA) liposome bilayers as a result of complexation (data of electron paramagnetic resonance spectroscopy); 40% protection of the liposomes from oxidation under the twofold excess of the biopolymers relative to the lipids in the ternary complexes.

Variations in the Size and ζ-Potential of Phosphatidylcholine Liposomes with Incorporated Nutriceuticals in the Course of their Initiated Oxidation

Phosphatidylcholine (PC) liposomes are widely used as models of living cell biomembranes for studying various biochemical processes proceeding in them, in particular, lipid peroxidation (LPO) and effects of different substances on this process. In this work, dynamic light scattering has been employed to study the dynamics of variations in the sizes and ζ-potentials of soybean PC liposomes during their oxidation at 37°С initiated by 2,2'-azobis(amidinopropane) dihydrochloride. The effects of α-linoleic acid and carnation essential oil incorprated into the liposomes, as well as the encapsulation of the liposomes with sodium caseinate, on these parameters have been investigated. It has been found that the average size of PC liposomes increases by 6–7% in the course of oxidation; however, no correlation between their sizes and accumulation of LPO products has been revealed. By the end of the oxidation, the absolute value of the ζ potential increases by three times. The inclusion of α-linoleic acid into liposomes substantially changes the dynamics of variations in their sizes and ζ potential. The presence of carnation essential oil in liposomes decreases the accumulation of conjugated dienes during the oxidation and stabilizes the sizes and ζ-potentials by the end of oxidation for both original liposomes and liposomes containing α-linoleic acid. Encapsulation of liposomes with sodium caseinate stabilizes the sizes and ζ-potentials of complex structures formed in the course of oxidation.

1H NMR study of the interaction of trans-resveratrol with soybean phosphatidylcholine liposomes

Resveratrol (RSV) is a well-known natural derivative with a wide range of biological and pharmacological activities. Despite of these demonstrated properties, it exhibits low both aqueous solubility and chemical stability and therefore low bioavailability. Consequently, the major concern of the technological research is to exploit delivery systems able to overcome bioavailability problems. In the recent past liposomes have been successfully studied for these purposes. In this paper, 1H-NMR spectroscopy, Nuclear Overhauser Spectroscopy (NOESY) as well as Paramagnetic Relaxation Enhancements (PRE) experiments have been carried out to quantitatively investigate the incorporation of resveratrol, at both the liposome preparation stage and by preformed liposomes, also with the aim to characterize resveratrol- soybean phosphatidylcholine (P90G) lipid bilayer interactions. Overall results of 1H NMR spectroscopy analysis suggest that RSV is located nearby the phosphocholine headgroups and also provide quantitative data on the incorporation of RSV (5% w/w), which corresponds to a 150-fold increase with respect to the solubility of RSV in water. Beside, considering that the same level of RSV incorporation was obtained via spontaneous uptake by preformed P90G liposomes, it can be concluded that RSV easily diffuses through the lipid bilayer.

SPC Liposomes as Possible Delivery Systems for Improving Bioavailability of the Natural Sesquiterpene β-Caryophyllene: Lamellarity and Drug-Loading as Key Features for a Rational Drug Delivery Design.

The natural sesquiterpene β-caryophyllene (CRY) has been highlighted to possess interesting pharmacological potentials, particularly due to its chemopreventive and analgesic properties. However, the poor solubility of this sesquiterpene in aqueous fluids can hinder its uptake into cells, resulting in inconstant responses of biological systems, thus limiting its application. Therefore, identifying a suitable pharmaceutical form for increasing CRY bioavailability represents an important requirement for exploiting its pharmacological potential. In the present study, the ability of soybean phosphatidylcholine (SPC) liposomes to improve bioavailability and absorption of CRY in cancer cells has been evaluated. Liposomal formulations of CRY, differing for lamellarity (i.e., unilamellar and multilamellar vesicles or ULV and MLV) and for the drug loading (i.e., 1:0.1, 1:0.3 and 1:0.5 mol/mol between SPC and CRY) were designed with the aim of maximizing CRY amount in the liposome bilayer, while avoiding its leakage during storage. The low-loaded formulations significantly potentiated the antiproliferative activity of CRY in both HepG2 and MDA-MB-468 cells, reaching a maximum IC50 lowering (from two to five folds) with 1:0.3 and 1:0.1 SPC/CRY MLV. Conversely, increasing liposome drug-loading reduced the ability for CRY release, likely due to a possible interaction between SPC and CRY that affects the membrane properties, as confirmed by physical measures.

Curcumin improved liposomal mitomycin-induced cell toxicity in bladder cancer cell

Objective (s): This study aimed at investigation of preparation and stability study of Mitomycin and Mitomycin loaded nanoliposems and efficacy of the combination of Mitomycin -loaded nanoliposomes and Curcumin versus Mitomycin in suppressing HTB-9 and L929 cell lines, in vitro.Materials and Methods: An HPLC method was validated based on Q2 (R1) International Conference on Harmonization (ICH) guideline for determination of Mitomycin in pharmaceutical samples. Soybean phosphatidylcholine (SPC) or hydrogenated soybean phosphatidylcholine (HSPC) mixed with cholesterol at 2:1 molar ratio respectively in two different groups to prepare Mitomycin nanoliposomes. Cell toxicity of free Mitomycin, Mitomycin loaded liposomes and curcumin was measured using MTT assay in bladder cancer cell line for treatment group and Fibroblast-like cell as control group. Also, propidium iodide staining was done to determine the level of DNA fragmentation.Results: The validated HPLC method showed stability based on the ICH guideline (n=3 and RSD<2%). Encapsulation efficiency values were 78 and 63 % for SPC and HSPC liposomes, respectively. Sizes of SPC and HSPC liposomes were 112 and 128 nm, respectively. Encapsulation efficiency of Mitomycin was 27 and 21 % for SPC and HSPC liposomes, respectively. Addition of Curcumin to the samples remarkably improved Mitomycin cytotoxicity. Concerning DNA fragmentation, Curcumin exhibited a protective effect when used in combination with Mitomycin.Conclusion: Synergistic effects of Curcumin and Mitomycin were observed in terms of cell toxicity. Together, since Curcumin exerts anti-oxidative properties, its co-administration with a chemotherapeutic agent might protect normal cells from adverse effects of such drugs.

Effect of oxymatrine HSPC liposomes on improving bioavailability, liver target distribution and hepatoprotective activity of oxymatrine

Oxymatrine (OMT) and matrine (MT) are two naturally occurring alkaloids, both of them provide anti-hepatitis effects. However OMT effect was heavily limited due to its low bioavailability, short half-life and whole body distribution. Herein, we investigated hydrogenated soybean phosphatidylcholine (HSPC) liposomes made by pH gradient active loading to understand the improved hepatoprotective effect mechanisms. Pharmacokinetics researches demonstrated the half-life time of OMT HSPC liposomes was 17.10h in mice. Compared with OMT solution, AUC (0–8) of OMT and MRT (0–8) of MT had been increased 11.8 fold and 14.3 fold in HSPC liposomes. Moreover, tissue distribution revealed the relative AUCs of total alkaloids in liver of OMT HSPC liposomes was as 4.18 times as that of OMT solution. Our data suggested that pathological topical necrosis and mild vacuolar degeneration of liver progressively returned to normal, and serum level of alanine-aminotransferase (ALT) and aspartate-aminotransferase (AST) were significantly reduced after treating with OMT HSPC liposomes in acute liver injury mice induced by CCl4. Pharmacokinetics, biodistribution and pathological researches manifested that HSPC liposomes served as an ideal and potential oxymatrine liver target carrier to prolong OMT retention time and maintain high therapeutically level in liver.

In vitro transdermal permeation and penetration properties for transfersomes of brucine

To prepare the liposomes and transfersomes of brucine, characterize their pharmaceutical properties, and compare their in vitro transdermal permeation properties. The liposomes and transfersomes of brucine were prepared by ammonium sulfate gradient method to investigate their pharmaceutical properties such as the particle size, encapsulation efficiency and deformation. The transdermal permeation properties in vitro of liposome and transfersomes from different prescriptions were compared by using modified Franz-diffustion cells with rat skin as the transdermal barrier. The results showed that the particle size of liposomes and transfersomes for brucine ranged from 100 nm to 150 nm, with even distribution for particle size. As compared with the soybean phosphatidylcholine (SPC) transfersomes, the encapsulation efficiency of complex phospholipid transfersomes was significantly improved. The deformation index of complex phospholipid transfersomes in brucine was 2.09 times and 1.76 times as much as SPC liposomes and SPC transfersomes respectively. The steady state flux of complex phospholipid transfersomes was 3.43 times and 1.41 times as much as SPC liposomes and SPC transfersomes. The steady state flux of the physical mixture of brucine and blank complex phospholipid transfersomes was 2.20 times as much as brucine solution. The concentration of complex phospholipid had effect on transdermal permeation of blank transfersomes. In conclusion, as compared with liposomes, the permeation behavior of transfersomes was significantly improved; complex phospholipid technology can improve the membrane phase behavior of transfersomes, and further improve the deformation index and transdermal flux of transfersomes; in addition, blank transfersomes have promoting effect on transdermal absorption of brucine.

Delivery of fluorescent-labeled cyclodextrin by liposomes: role of transferrin modification and phosphatidylcholine composition

Drug-in-CD-in-liposome (DCL) systems which encapsulate the drug/CD inclusion complexes into inner aqueous phase of liposomes have been applied as a novel strategy to improve efficacy of lipophilic antitumor drugs. The aim of this work was to assess the role of transferrin (Tf) modification and phosphatidylcholine (PC) composition on the properties of liposomes containing hydroxypropyl-β-cyclodextrin (HP-β-CD). Fluorescence dye, FITC, was conjugated with HP-β-CD to facilitate the analysis. The resulting FITC-HP-β-CD was further encapsulated into liposomes and then the liposomes were modified with Tf. The FITC-HP-β-CD-loaded liposomes with different PC compositions were compared in terms of particle size, zeta potential, FITC content, FITC-HP-β-CD leakage, phase transition temperature (Tm) and cellular uptake. The apparent partition coefficient values of different PCs were also determined. Compared to PEGylated liposomes, FITC-HP-β-CD-loaded liposomes modified with Tf had been proved to significantly increase vesicle stability and specific cellular uptake. Moreover, PC composition affected the properties of liposomes. Soybean phosphatidylcholine (SPC) liposomes modified with Tf were found to be more easily internalized into tumor cells than 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and hydrogenated soybean phosphatidylcholine (HSPC) while Tf density on the liposomal surface was similar. And the lipophilicity of SPC was found to be much higher than DPPC and HSPC. Collectively, by the optimization of PC composition, the development of DCL modified with Tf might represent a potential strategy for the antitumor application of lipophilic drugs.

Soybean phosphatidylcholine liposomes as model membranes to study lipid peroxidation photoinduced by pterin

Oxidized pterins, efficient photosensitizers under UVA irradiation, accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder. Soybean phosphatidylcholine (SoyPC) liposomes were employed as model membranes to investigate if pterin (Ptr), the parent compound of oxidized pterins, is able to photoinduced lipid peroxidation. Size exclusion chromatography and dialysis experiments showed that Ptr is not encapsulated inside the liposomes and the lipid membrane is permeable to this compound. The formation of conjugated dienes and trienes, upon UVA irradiation, was followed by absorption at 234 and 270nm, respectively. The photoproducts were characterized by mass spectrometry and oxygenation of SoyPC was demonstrated. In addition, analysis of MS/MS spectra suggested the formation hydroperoxides. Finally, the biological implications of the findings are discussed.

Liposomal Entrapment of 4-Nerolidylcatechol: Impact on Phospholipid Dynamics, Drug Stability and Bioactivity

Liposomes containing 4-nerolidylcatechol (4-NC), the major metabolite isolated from Pothomorphe umbellata, were obtained and characterized. Influence of liposomal encapsulation on chemical stability of 4-NC and on cytotoxicity profile of this drug was evaluated. Soybean phosphatidylcholine liposomes were prepared by lipid film hydration followed by extrusion. Entrapment efficiency for 4-NC was approximately 92%. Mean diameter of liposomes was 100 nm with a polydispersity index below 0.13. Liposomal 4-NC (L4-NC) and free drug (F4-NC) were submitted to forced degradation assays, monitored by HPLC. Photodegradation assay followed ICH Guidelines, using a photostability chamber equipped with both UV and white light sources. Liposomal encapsulation was able to markedly reduce 4-NC degradation rates under all the conditions tested. L4-NC showed a half-live approximately 15% higher than F4-NC under light exposure. After 72 hours, acid and base hydrolysis of F4-NC lead to 13 and 16% of degradation, respectively. However, no degradation was observed in L4-NC. EPR spectra of liposomal membrane showed that greatest changes in membrane properties were obtained when 5-doxyl stearic acid was used as the spin label, indicating a marked decrease in the fluidity of the bilayer. Following incubation with K562 cells, 4-NC showed a concentration-dependent cytotoxicity profile, while L4-NC exhibited a time and concentration-dependent profile, consistent with a controlled drug release system. F4-NC induced extensive hemolysis under isotonic conditions; conversely liposomal encapsulation protected erythrocytes from 4-NC induced lysis. Liposomal 4-NC resulted in a hemocompatibility and stable formulation, representing a viable drug delivery system to further investigate in vivo performances of 4-NC in pre clinical studies.

Antioxidant activities and functional properties of protein and peptide fractions isolated from salted herring brine

In the present study proteins isolated from herring brine, which is a by-product of marinated herring production were evaluated for their functional properties and antioxidant activity. Herring brine was collected from the local herring industry and proteins were precipitated by adjusting the pH to 4.5 and the obtained supernatant was further fractionated by using ultrafiltration membranes with molecular weight cut offs of 50, 10 and 1kDa. The obtained >50kDa, 50–10kDa, 10–1kDa fractions and pH precipitated fraction were studied for their functional properties and antioxidant activity. Functional properties revealed that >50kDa polypeptides showed good emulsion activity index when compared to the other fractions. However all fractions had low emulsion stability index. The pH precipitated fraction showed the highest foaming capacity and stability at pH 10. The 50–10kDa and 10–1kDa peptide fractions showed good radical scavenging activity and reducing power at a concentration of 0.5mg protein/ml. All the fractions demonstrated low iron chelating activity and did not inhibit oxidation in a soybean phosphatidylcholine liposome model system. However all the fractions were to some extent able to delay iron catalyzed lipid oxidation in 5% fish oil in water emulsions and the 10–50kDa fraction was the best. These results show the potential of proteins and peptide fractions recovered from waste water from the herring industry as source of natural antioxidants for use in food products.

Relaxivities of magnetoliposomes: The effect of cholesterol

We present relaxivities measurements for both the longitudinal and transverse relaxations of two types of liposomes loaded with ultra small superparamagnetic iron oxide nanoparticles. The magnetoliposome systems presented are soybean phosphatidylcholine liposomes, with and without cholesterol, in the phospholipid bilayer with different molar ratios lipid:cholesterol. In fact, cholesterol is needed to obtain stable liposomes for intravenous administration. The longitudinal and transverse relaxivities were measured with a NMR spectrometer in a 7T magnetic field. For the studied concentrations, the liposomes show a negligible effect on the longitudinal relaxation time T1 of the medium, but they are very efficient on decreasing the transverse relaxation time T2, the behaviour one expects for a negative CA. We observed a lower transverse relaxivity for the magnetoliposome nanosystem with cholesterol, which strongly decreases with the cholesterol content in the liposome bilayer.