Incorporation Of Cholesterol Research Articles

Secretory phospholipase A2 responsive liposomes exhibit a potent anti-neoplastic effect in vitro, but induce unforeseen severe toxicity in vivo

The clinical use of liposomal drug delivery vehicles is often hindered by insufficient drug release. Here we present the rational design of liposomes optimized for secretory phospholipase A2 (sPLA2) triggered drug release, and test their utility in vitro and in vivo. We hypothesized that by adjusting the level of cholesterol in anionic, unsaturated liposomes we could tune the enzyme specificity based on membrane fluidity, thus obtaining liposomes with an improved therapeutic outcome and reduced side effects. Cholesterol is generally important as a component in the membranes of liposome drug delivery systems due to its stabilizing effects in vivo. The incorporation of cholesterol in sPLA2 sensitive liposomes has not previously been possible due to reduced sPLA2 activity. However, in the present work we solved this challenge by optimizing membrane fluidity. In vitro release studies revealed enzyme specific drug release. Treatment of two different cancer cell lines with liposomal oxaliplatin revealed efficient growth inhibition compared to that of clinically used stealth liposomes. The in vivo therapeutic effect was evaluated in nude NMRI mice using the sPLA2 secreting mammary carcinoma cell line MT-3. Three days after first treatment all mice having received the novel sPLA2 sensitive liposome formulation were euthanized due to severe systemic toxicity. Thus the present study demonstrates that great caution should be implemented when utilizing sPLA2 sensitive liposomes and that the real utility can only be disclosed in vivo. The present studies have clinical implications, as sPLA2 sensitive formulations are currently undergoing clinical trials (LiPlaCis®).

Hybrid Lipids Inspired by Extremophiles and Eukaryotes Afford Serum‐Stable Membranes with Low Leakage

This paper presents a new hybrid lipid that fuses the ideas of molecular tethering of lipid tails used by archaea and the integration of cholesterol groups used by eukaryotes, thereby leveraging two strategies employed by nature to increase lipid packing in membranes. Liposomes comprised of pure hybrid lipids exhibited a 5-30-fold decrease in membrane leakage of small ions and molecules compared to liposomes that used only one strategy (lipid tethering or cholesterol incorporation) to increase membrane integrity. Molecular dynamics simulations reveal that tethering of lipid tails and integration of cholesterol both reduce the disorder in lipid tails and time-dependent variance in area per lipid within a membrane, leading to tighter lipid packing. These hybrid lipid membranes have exceptional stability in serum, yet can support functional ion channels, can serve as a substrate for phospholipase enzymes, and can be used for liposomal delivery of molecules into living cells.

Kinetic stability and membrane structure of liposomes during in vitro infant intestinal digestion: Effect of cholesterol and lactoferrin.

The effects of cholesterol and lactoferrin on the kinetic stability and membrane structural integrity of negatively charged liposomes under in vitro infant intestinal digestion conditions were elucidated using dynamic light scattering, pH-stat titration, Fourier transform infrared spectroscopy, and pyrene steady state fluorescence probes. The liposomes had a smaller particle diameter, a wider size distribution, and a greater negative charge after digestion. The incorporation of cholesterol into the phospholipid bilayers resulted in a more ordered conformation in the aliphatic tail region and reduced micropolarity, indicating that cholesterol can improve the structural stability of liposomal membranes against intestinal environmental stress. Lactoferrin coverage facilitated the release of free fatty acids and increased the microfluidity of the bilayers, reducing the structural integrity of the liposomes. This study provides useful information on the design of liposomes and other microcapsules with improved and controlled release properties during digestion for particular groups of people.

Effect of cholesterol-loaded cyclodextrins on cryosurvival of dog spermatozoa.

Cryopreservation affects integrity of cholesterol and phospholipids in the plasma membrane of sperm leading to decreased fertility of frozen-thawed semen. Cholesterol-loaded cyclodextrins (CLC) have been shown to improve post-thaw semen quality in various species. The aim of this study was to investigate the optimal concentration of CLC for better post-thaw semen quality in dogs. Semen collection, through digital manipulation, was conducted once a week in four adult German shepherd dogs (n=20 ejaculates; five ejaculates/dog). Semen samples with mass motility>3 (0: without movement; 5: fast progressive movement), motility >70% and concentration >200×106 /ml were pooled and processed in Tris-citrate extender containing 0, 1, 2 or 3mg of CLC. The post-thaw quality was assessed on the basis of percentage motility, morphological abnormalities, live/dead ratio and plasma membrane, acrosome and DNA integrity, evaluated using anova and further analysed by Tukey's range test, if applicable. The addition of CLC showed an overall improvement in post-thaw semen quality. Among various treatment groups, and when compared to the control, the percentages of motile (55.5%), viable (65%), plasma membrane intact (56.7%), acrosome intact (49.2%) and DNA intact (98%) spermatozoa were significantly higher in 2mg/ml CLC group (p<.05). It is concluded that incorporation of cholesterol in semen extender results in a beneficial increase in post-thaw semen quality in dogs.

Screening of Indigenous Lactic Acid Bacteria for Cholesterol Lowering and Additional Probiotic Attributes

The study was aimed to evaluate the cholesterol lowering property and probiotic attributes of lactic acid bacteria (LAB) isolated from indigenous fermented milk products of Yak from the eastern region of Sikkim Himalayas. A total of 7 indigenous LAB were screened for putative probiotic features namely hypocholesterolaemic effect, bile salt hydrolase activity, acid tolerance and cell surface hydrophobocity. The possible mechanisms of cholesterol lowering like bile salt hydrolase (BSH) enzyme activity, bile acid deconjugation, cholesterol co-precipitation and cholesterol incorporation were studied. Isolates were subjected to direct plate assay in MRS agar plates supplemented with 0.5% (w/v) taurodeoxycholic acid sodium salt for the presence of bile salt hydrolase (BSH) enzyme. Screening revealed Lactobacillus paraplantarum YD11S and Lactobacillus plantarum YD5S showing bile acid deconjugation while co-precipitation was observed in YY1 Enterococcus lactis and Lactobacillus pentosus YD8S as the cholesterol lowering mechanism. Lactobacillus plantarum YD9S showed good bile acid deconjugation and co-precipation. Enterococcus faecium YHC12 was BSH-ve and showed cellular incorporation to be its mechanism of cholesterol lowering.

Mechanisms responsible for the hypocholesterolaemic effect of regular consumption of probiotics.

CVD affect a large proportion of the world's population, with dyslipidaemia as the major risk factor. The regular consumption of both probiotic bacteria and yeast has been associated with improvement in the serum lipid profile. Thus, the present review aims to describe and discuss the potential mechanisms responsible for the hypocholesterolaemic effect of regular consumption of probiotic bacteria and yeast. Regarding the hypocholesterolaemic effect of probiotic bacteria, the potential mechanisms responsible include: deconjugation of bile salts; modulation of lipid metabolism; and decreased absorption of intestinal cholesterol through co-precipitation of intestinal cholesterol with the deconjugated bile salts, incorporation and assimilation of cholesterol in the cell membrane of the probiotics, intestinal conversion of cholesterol in coprostanol, and inhibition of the expression of the intestinal cholesterol transporter Niemann-Pick C1 like 1 (NPC1L1) in the enterocytes. The potential mechanisms responsible for the hypocholesterolaemic effect of probiotic yeasts include: deconjugation of bile salts; co-precipitation of intestinal cholesterol with the deconjugated bile salts; incorporation and assimilation of cholesterol in the cell membrane; and inhibition of hepatic cholesterol synthesis. The regular consumption of probiotic bacteria and yeast, as a non-pharmaceutical approach to help manage cardiovascular risk, holds promise, according to the beneficial hypocholesterolaemic effects described herein. However, the hypocholesterolaemic effects vary according to the strains used, the physiological state of the host, and the type of diet to which the probiotics are added. Further studies are necessary to fill the gaps with regard to the knowledge related to this topic.

The inhibitory activity of herbal medicines on the keys enzymes and steps related to carbohydrate and lipid digestion

BackgroundObesity and overweight are consistently associated with metabolic disorders including hyperglycemia and hyperlipidemia. Herbal medicines have been currently suggested as an alternative source of potentially useful antihyperglycemic, antihyperlipidemic, antioxidant activities. The objective of this study was to assess the in vitro inhibitory effects of eleven herbal medicines on carbohydrate and lipid digestive enzymes and the key steps of lipid digestion including the inhibition of micelle formation and the ability to bind bile acid. In addition, antioxidant activity of herbal medicines was also investigated.Methodsα-Glucosidase, pancreatic α-amylase, pancreatic lipase, and pancreatic cholesterol esterase inhibitory activities of aqueous extract of herbal medicines were measured using the enzymatic colorimetric assay. The formation of cholesterol micelles was determined using the cholesterol assay kit. The bile acid binding was measured using the colorimetric assay. Antioxidant activities were assessed by using four methods including Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorbance capacity ORAC), superoxide radical scavenging activity (SRSA), and hydroxyl radical scavenging activity (HRSA).ResultsThe extracts (1 mg/mL) markedly inhibited intestinal maltase (5.16 − 44.33 %), sucrase (1.25–45.86 %), pancreatic α-amylase (1.75–12.53 %), pancreatic lipase (21.42–85.93 %), and pancreatic cholesterol esterase (2.92–53.35 %). The results showed that all extracts exhibited the inhibitory activity against pancreatic lipase with the IC50 values ranging from 0.015 to 4.259 mg/mL. In addition, the incorporation of cholesterol into micelles was inhibited by the extracts (6.64–33.74 %). The extracts also bound glycodeoxycholic acid (9.9–15.08 %), taurodeoxycholic acid (12.55–18.18 %), and taurocholic acid (11.91 − 18.4 %). Furthermore, the extracts possessed various antioxidant activities including the TEAC values (0.50 − 4.70 μmol trolox/mg dried extract), the ORAC values (9.14–44.41 μmol trolox/mg dried extract), the SRSA (0.31 − 18.82 mg trolox/mg dried extract), and the HRSA (0.05–2.29 mg trolox/mg dried extract). The findings indicated that Syzygium aromaticum, Phyllanthus amarus, Thunbergia laurifolia were the effective promising antihyperglycemic and antihyperlipidemic agents. Statistical analysis demonstrated strong positive significant correlations between the contents of phenolic compounds and % inhibition of pancreatic lipase (r = 0.885, p < 0.001), % inhibition of pancreatic cholesterol esterase (r = 0.761, p < 0.001), and the TEAC value (r = 0.840, p < 0.001). Furthermore, there was a strongly positive correlation between the TEAC value and % inhibition of pancreatic cholesterol esterase (r = 0.851, p < 0.001) and % inhibition of pancreatic lipase (r = 0.755, p < 0.001).ConclusionsThree herbal medicines including Syzygium aromaticum, Thunbergia laurifolia, and Phyllanthus amarus markedly inhibited the intestinal α-glucosidase, pancreatic α-amylase, pancreatic lipase, and pancreatic cholesterol esterase. They also reduced formation of cholesterol micelle and bound bile acid. The findings indicate that these herbal medicines might be a promising agent for antihyperglycemic, antihyperlipidemic, and antioxidant activities.

A Cantilever‐based Biosensor for Real‐time Monitoring of Interactions between Amyloid‐β(1–40) and Membranes Comprised of Phosphatidylcholine Lipids with Different Hydrophobic Acyl Chains

AbstractAccumulating evidence suggests that interaction between amyloid‐β (Aβ) and cell membrane is crucial to the pathogenesis of Alzheimer's disease (AD), and thus an increasing understanding of the impact of membrane composition on Aβ‐membrane interaction becomes essential for the mechanism elucidation of Aβ‐membrane interaction and the early diagnosis of AD. In this work, electrically neutral phosphatidylcholine (PC) as the most major class of membrane phospholipids, including 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine (DPPC), 1,2‐distearoyl‐sn‐glycero‐3‐phosphocholine (DSPC), 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC), and Aβ(1–40) as the most common amyloid protein were selected as the research subjects, and a developed cantilever‐based biosensor, on which liposomes comprised of PC lipids were immobilized, was applied to characterize in real time the interactions between Aβ(1–40) and membranes comprised of PC lipids with different hydrophobic acyl chains, and to evaluate the effect of cholesterol incorporated in membrane on Aβ‐membrane interaction during the whole process of Aβ(1–40) fibrillization. The results illustrate that the interaction between Aβ(1–40) and PC membrane can be divided into three stages, which are related to the change in molecular states of Aβ. More importantly, it is found that membranes comprised of PC lipids with shorter saturated acyl chains show higher interaction ability with Aβ(1–40), and the incorporation of cholesterol into PC bilayer can remarkably accelerate and strengthen Aβ(1–40)‐membrane interaction. These results confirm that hydrophobicity is the main driving force for the interactions between Aβ(1–40) and PC membranes. In return, the above results enlightened us to apply the current micro‐cantilever immobilized with cholesterol‐containing DPPC liposomes to challenge the detection of low‐concentration Aβ(1–40). This time 50‐nM Aβ(1–40) in aqueous solution has been effectively detected, suggesting that this proposed detection technique would contribute to Aβ detection and early diagnosis of AD in the future.

Neuronal sphingolipidoses: Membrane lipids and sphingolipid activator proteins regulate lysosomal sphingolipid catabolism.

Glycosphingolipids and sphingolipids of cellular plasma membranes (PMs) reach luminal intra-lysosomal vesicles (LVs) for degradation mainly by pathways of endocytosis. After a sorting and maturation process (e.g. degradation of sphingomyelin (SM) and secretion of cholesterol), sphingolipids of the LVs are digested by soluble enzymes with the help of activator (lipid binding and transfer) proteins. Inherited defects of lipid-cleaving enzymes and lipid binding and transfer proteins cause manifold and fatal, often neurodegenerative diseases. The review summarizes recent findings on the regulation of sphingolipid catabolism and cholesterol secretion from the endosomal compartment by lipid modifiers, an essential stimulation by anionic membrane lipids and an inhibition of crucial steps by cholesterol and SM. Reconstitution experiments in the presence of all proteins needed, hydrolase and activator proteins, reveal an up to 10-fold increase of ganglioside catabolism just by the incorporation of anionic lipids into the ganglioside carrying membranes, whereas an additional incorporation of cholesterol inhibits GM2 catabolism substantially. It is suggested that lipid and other low molecular modifiers affect the genotype-phenotype relationship observed in patients with lysosomal diseases.

Antihyperlipidemic Activities of Isolated bio Compounds of Aegle Marmelos

The present work was done to study qualitative investigation of extractability of the useful compounds from Aeglemarmelos leaves via supercritical fluid extraction technique (SFE) and to evaluate antihyperlipidemic activity of Aeglemarmelos(Am).The obtained extract and fractions were treated on Triton induced rat models and the results showed lowering the lipid profile levelin the experimental models by in-vivo methods. The fractions of Aeglemarmelos(AmF1) also exhibited excellent anti hyperlipedimic property at 3 rd week and also lowering the serum cholesterol, triglycerides in Triton induced rats. The most important ingredients present in plant communities turn out to be alkaloids, terpenoids, steroids, phenols glycosides and tannins are responsible for monitoring the normal lipid profile in Triton induced rats due to LA of lecithin acetyl transferase (LCAT), which regulates lipids concentration. The LCAT plays a key role in the incorporation of free cholesterol into HDL (this may increase HDL) and transferring it back to VLDL and LDL which are taken back later in liver cells.The changes in the level of serum lipids in experimental rats areillustrated in (Table 1). The total Cholesterol, TG1, LDL and VLDC significantlydecreased (P<0.001) and simultensely there is increase in level of HDLs.Supercritical Fluid extraction of leaves of Aeglemarmelos(Am)possess significantantihyperlipidemic activity as compared to control group.

Tannic acid and cholesterol–dopamine as building blocks in composite coatings for substrate‐mediated drug delivery

AbstractComposite coatings are considered a promising approach to tailor the biointerface between a (implantable) biomaterial and adhering/surrounding cells or tissue. In this context, composite coatings assembled using a polymer matrix with embedded drug deposits are particularly interesting due to the advanced control over cargo loading, retention and release. Herein, we compare the assembly of such films consisting of various types of liposomes as subunits within a polymer film of either polydopamine (PDA) or, for the first time, tannic acid (TA) as an alternative. It is found that TA is a suitable capping layer for liposome‐coated substrates which allows for post‐modification. The composite coatings are suitable for supporting hepatocyte adhesion depending on the terminating polymer layer. Furthermore, incorporation of cholesterol–dopamine (Ch‐DA) conjugates into the zwitterionic liposomes increases the numbers of deposited subunits. Finally, cytotoxic paclitaxel is loaded into the liposomes and delivered to the adhering hepatocytes. The capability of reducing hepatocyte adhesion to the composite coating varied. Composite coatings consisting of negatively charged liposomes with Ch‐DA and a PDA capping layer are found to be most efficient after 24 and 48 h. Taken together, this fundamental comparison of different composite coatings illustrates the excellent opportunities to engineer the biological response towards the application in mind. © 2016 Society of Chemical Industry

The Influence of Lipid Bilayer Physicochemical Properties on Gramicidin A Conformer Preferences

The conformational preferences adopted by gramicidin A (GA) dimers inserted into phospholipid bilayers are reported as a function of the bilayer cholesterol content, temperature, and incubation time. Through use of vesicle capture-freeze drying methodology, GA dimers were captured in lipid bilayers and the conformational preferences of the complex were analyzed using ion mobility-mass spectrometry. Perturbations that affect the physicochemical interactions in the lipid bilayer such as cholesterol incorporation, temperature, and incubation time directly alter the conformer preferences of the complex. Regardless of bilayer cholesterol concentration, the antiparallel double helix (ADH) conformation was observed to be most abundant for GA dimers in bilayers composed of lipids with 12 to 22 carbon acyl chains. Incorporation of cholesterol into lipid bilayers yields increased bilayer thickness and rigidity, and an increased abundance of parallel double helix (PDH) and single-stranded head-to-head (SSHH) dimers were observed. Bilayers prepared using 1,2-dilauroyl-sn-glycero-3-phosphocholine, a lipid with 12 carbon acyl chains, yielded a nascent conformer that decreased in abundance as a function of bilayer cholesterol content. High resolution ion mobility-mass spectrometry data revealed two peaks in the ADH region suggesting that ADH populations are composed of two distinct conformers. The conformer preferences of GA dimers from 1,2-distearoyl-sn-glycero-3-phosphocholine bilayers were significantly different for samples incubated at 4°C vs. 60°C; increased cholesterol content yielded more PDH and SSHH at 60°C. The addition of cholesterol as well as incubating samples of 1,2-distearoyl-sn-glycero-3-phosphocholine at 60°C for 24–72 h yielded an increase in PDH and SSHH abundance.

Effect of cholesterol on the phase state and permeability of mixed liposomes composed of anionic diphosphatidylglycerol and zwitterionic dipalmitoylphosphatidylcholine

The incorporation of cholesterol into a solid liposomal membrane makes the membrane liquid with a higher lipid mobility (a lower microviscosity) and suppresses the membrane permeability toward inorganic ions.

Cholesterol-Loaded Cyclodextrin Increases the Cholesterol Content of Goat Sperm to Improve Cold and Osmotic Resistance and Maintain Sperm Function after Cryopreservation.

The success of semen cryopreservation depends on sperm membrane integrity and function after thawing. Cholesterol-loaded cyclodextrin (CLC) is used for in vitro incorporation of cholesterol to protect cells against cold temperatures. We hypothesized that CLC treatment also enhances sperm cholesterol content to increase tolerance to osmotic shock and cryoresistance, thereby improving fertility. We confirmed the fact that treatment of goat semen with 3 mg/ml CLC increases sperm cholesterol content using both the Liebermann-Burchard approach and filipin III labeling of membrane cholesterol. Sperm were then treated with or without CLC and cryopreserved. After thawing, sperm cholesterol dramatically fell, even in the presence of CLC, which explains the mechanism of cryocapacitation. CLC treatment, however, maintained a normal prefreeze cholesterol level in sperm after cryopreservation. Furthermore, fresh sperm treated with CLC and subjected to either cold shock or incubated in hypo-, iso-, and hyperosmotic media, designed to mimic stresses associated with freezing/thawing, displayed increased temperature and osmotic tolerance. CLC treatment also improved sperm viability, motility, and acrosome integrity after thawing. Furthermore, CLC treatment did not affect the sperm's ability to undergo in vitro capacitation according to chlortetracycline fluorescence and protein tyrosine phosphorylation. A pilot field trial demonstrated that artificial insemination with sperm that underwent increased cholesterol levels following CLC treatment yielded higher fertility ( ITALIC! P< 0.1) and proliferation ( ITALIC! P< 0.05) rates in vivo than untreated semen from the same ejaculate samples. These observations suggest that CLC treatment could be used to improve cryoprotection during the freezing and thawing of goat sperm.

Molecular structure and dynamical properties of niosome bilayers with and without cholesterol incorporation: A molecular dynamics simulation study

Niosomes are non-ionic surfactant vesicles having a bilayer structure formed by self-assembly of hydrated surfactants, usually with cholesterol incorporation. Stability and mechanical properties of niosomes strongly depend on type of non-ionic surfactants and compositions used. In this study we present the structural and dynamical properties of niosome bilayers composed of sorbitan monostearate (Span60) with 0% and 50% cholesterol compositions which are investigated by using molecular dynamics simulations. The simulations reveal that niosome bilayer without cholesterol prefer to form in the gel phase with a higher order structure, while in the presence of cholesterol the bilayer exhibits more fluidity having a less ordered structure. The niosome bilayer with 50% cholesterol inclusion shows an increase of area per lipid (∼11%) and thickness (∼39%) compared with the niosome bilayer without cholesterol. The Span60 tailgroup orientation of the niosome bilayers without cholesterol exhibits more tilt (34.5o±0.5) than that of the bilayer with 50% cholesterol (15.4o±0.8). Additionally, our results show that the addition of cholesterol to the bilayer causes the higher in lateral and transverse diffusion, as well as an increase in the hydrogen bond number between Span60 and water. Such characteristics not only enhance the niosome stability but also increase the fluidity, which are necessary for the niosomal drug delivery.

Ceramide Studies from the Nano To the Microscale

Ceramides (N-acyl sphingosines) are minor but important biomembrane components. They possess a number of very unusual biophysical properties when incorporated into phospholipid bilayers, among them their capacity to segregate laterally into ceramide-rich domains, their ability to make bilayers permeable even to protein-sized solutes, or to promote transbilayer (flip-flop) lipid motion. The mechanisms underlying these properties are not fully explained yet, but they are most probably related to the capacity of the ceramide polar head groups to establish a complex network of H-bonds. This allows the generation of dynamic structures effectively expanding the nanometre-to-micrometre scale, with lifetimes long enough to be physiologically meaningful. At the low end of the size scale, the hydration of the ceramide headgroup has been determined. Water is observed to preferentially hydrate the two hydroxyl groups and the carbonyl oxygen over the amide NH motif. Moreover, water molecules are associated with the headgroup in such a way that they bridge between the carbonyl motif and the nearest neighbour hydroxyl group. At the micron scale, ceramides have been shown to generate extensive gel bilayer phases in mixtures with sphingomyelins and/or cholesterol. Binary sphingomyelin/ceramide mixtures below 33 mol% ceramide promote the generation of laterally segregated micron-sized ceramide-rich domains. Cholesterol incorporation into the binary mixtures at a high cholesterol and ceramide ratios abolishes any sphingomyelin/ceramide binary domains. Bilayers with gel phase properties different from any of the pure or binary samples are observed instead. The data support no displacement of cholesterol by ceramide or vice versa under these conditions, but rather a preferential interaction between the two hydrophobic lipids. The recent discovery in mammals of a whole family of 1-deoxyceramides, with a different set of H-bonding patterns, will bring along its own collection of inter-molecular associations over a yet unknown length scale.

Multiliposomal nanocontainers based on anionic solid liposomes and spherical polycationic brushes

The incorporation of cholesterol in membrane of liposomes in gel state opens the gates of their usage as cargo-carrying component in complex multiliposomal nanocontainers.

D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell.

Hypocholesterolaemic mechanism of bitter melon aqueous extracts via inhibition of pancreatic cholesterol esterase and reduction of cholesterol micellar solubility

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.

Preparation and Characterization of Rutin-loaded Nanophytosomes

Background: Plant-derived materials are increasingly gaining attention as dietary supplements and due to their role in medicinal application. Rutin, a phenolic antioxidant, is a member of bioflavonoids which has been demonstrated to scavenge superoxide radicals and is believed to be a vital nourishing supplement due to its ability to strengthen and modulation of the permeability of the blood vessels walls. However, Rutin shows poor absorption when administered orally and its bioavailability is an important restrictive factor. Purpose: The present study was aimed to prepare and characterize a stable Rutin-loaded nanophytosomal formulation to improve its antioxidant property and bioavailability. Methods: Rutin-loaded nanophytosomes were prepared by phosphatidylcholine (PC) and cholesterol by thin layer hydration method. The physicochemical properties of prepared nanophytosomes were evaluated using particle size analyses, Furrier transformation infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Stability of the prepared nanophytosomes was also investigated during three weeks of storage period. Results: Results showed that formulation with the Rutin: PC molar ratio of 1:2 possess lowest particle size and the incorporation of cholesterol improved the physical stability of nanophytosome for over three weeks. FTIR and DSC analysis showed the formation of Rutin-phospholipid complex during the formulation development process. Conclusion: Results of the present study showed that nanophytosome can be introduced as a useful carrier for fortifying herbal medicinal compounds for application the formulation of various food and pharmaceutical products.