According to the conventional Gibbs adsorption model, which is a common assumption about the molecular concentration at surfaces, the adsorbed film of soluble amphiphiles is located at the air/solution interface just like Langmuir monolayer which is illustrated in many physical chemistry text books on “Colloid and Interface Science”. According to many proofs of the experimental results here, the newer idea for the surface adsorption is confirmed and explained, which is quite different from the conventional Gibbs surface excess model at the air/solution interface.
Various factors affect intestinal absorption of cholesterol and plant sterols and stanols. Plant sterols and stanols are generally less absorptive than cholesterol. Differential absorption rates among various plant sterols and stanols have been also reported. Although it was suggested that differential absorption among cholesterol and various plant sterols was determined by difference in excretion rates of sterols and stanols through ATP-binding cassette transporter (ABC) G5/ABCG8 of intestinal cells, our study suggests that affinity for and solubility in bile salt micelles can be important determinants for differential absorption of plant sterols and stanols. It was also suggested that plant sterols were transiently incorporated into intestinal cells and then excreted to intestinal lumen through ABCG5/ABCG8. However, in a rat study, transient incorporation of sitosterol into intestinal cells was not observed, suggesting that sitosterol is differentiated from cholesterol at the incorporation site of intestinal cells. It is well established that plant sterols inhibit intestinal absorption of cholesterol and exert a hypocholesterolemic activity. Plant sterols are solubilized in bile salt micelles as cholesterol. Our study clearly showed that because the sterol-solubilizing capacity of bile salt micelles was limited, plant sterols solubilized in micelles reduced the solubility of cholesterol. This can be the major cause of inhibition of cholesterol absorption by plant sterols. Pancreatic cholesterol esterase accelerates intestinal absorption of unesterified cholesterol. Although it was suggested that cholesterol esterase accelerated esterification of cholesterol incorporated into intestinal cells and acted as a transporter at the surface of intestinal cells, our research revealed that the accelerated cholesterol absorption was caused by hydrolysis of phosphatidylcholine in bile salt micelles. It is thought that hydrolysis of phosphatidylcholine reduces the affinity of cholesterol for the micelles and accelerates the incorporation of cholesterol released from the micelles into intestinal cells.
Helichrysum microphyllum Cambess. subsp. tyrrhenicum Bacch., Brullo e Giusso (Asteraceae), previously known as Helichrysum italicum ssp. microphyllum (Willd.) Nyman, is one of the many endemic species growing in Sardinia, Corsica and Balearic Islands. In the present work the composition of the essential oil obtained from a population of H. microphyllum ssp. thyrrenicum growing in a littoral location of La Maddalena Archipelago was investigated by GC-FID and CG-MS. The major compounds of the oil were the monoterpene ester neryl acetate (18.2%), the oxygenated sesquiterpene 5-eudesmen-11-ol (rosifoliol, 11.3%), the sequiterpene hydrocarbons δ-cadinene (8.4%) and γ-cadinene (6.7%), showing a peculiar composition in comparison with other Sardinian populations. The oil was tested for cytotoxicity on three human tumor cell lines (MDA-MB 231, HCT116 and A375) by MTT assay showing a strong inhibitory activity on human malignant melanoma cells A375 (IC50 of 16 µg/ml). In addition the oil was assessed for antioxidant activity by DPPH and ABTS assay.
The problem of poor bioavailability and clinical efficacy of curcumin can be sorted out after converting crystalline Curcumin (CrysCur) into amorphous NanoCurcumin (NanoCur). Amorphous NanoCur was prepared by converting into nanoemulsion (o/w) using water titration method. The formulation were pre-screen by different physical stress tests, followed by in vitro release study, zeta potential, viscosity, transmittance, globule size distribution and ex vivo studies. The morphology of the NanoCur was determined using transmission electron microscopy (TEM) which revealed fairly spherical shape and good correlation with droplet size distribution study. The NanoCur was converted to gel using Cabopol 934. The composition of optimized NanoCur was curcumin (0.154% w/w), Carbopol 934 (0.702% w/w), ethanolic oil phase [ethanol (0.013% w/w): Capryol 90 (0.015%w/w)], Tween 20 (0.076%w/w) as surfactant, PEG 200 (0.038%w/w) as a co-surfactant and distilled water (q.s) as hydration phase. The steady state flux (Jss), permeability coefficient (Kp) and enhancement ratio (Er) of NanoCur gel was determined and compared with CrysCur gel. Anti-inflammatory effects of the formulations were evaluated in carrageenan-induced paw edema method in rats using Diclofenac as a reference. These ant-inflammatory effects of NanoCur was highly significant (p<0.001) compared to CrysCur and significantly (p<0.05) comparable with standard Diclofenac. The histology of the formulation treated skin showed insignificant changes in the integrity except in the group treated with NanoCur. The slight disruption in the integrity of skin may be because of surfactant present in the nano formulations. Short term storage stability showed insignificant changes in the droplet size and zeta potential, proving its high shelf-life. Finally, it was concluded that NanoCur could be a promising tool in the management of topical inflammation.
Hydrazide derivatives have been synthesized from methyl esters, hydrazones and vegetable oils. They are important due to their diverse applications in pharmaceutical products, detergents as well as in oil and gas industries. The chemical synthesis of fatty hydrazides is well-established; however, only a few publications described the synthesis of fatty hydrazide derivatives, particularly, when produced from refined, bleached and deodorized palm olein. Here, the synthesis and characterization of N,N-dimethyl fatty hydrazides are reported. The N,N-dimethyl fatty hydrazides was successfully synthesized from fatty hydrazides and dimethyl sulfate in the presence of potassium hydroxide with the molar ratio of 1:1:1, 6 hours reaction time and 80℃ reaction temperature in ethanol. The product yield and purity were 22% and 89%, respectively. The fatty hydrazides used were synthesized from refined, bleached and deodorized palm olein with hydrazine monohydrate at pH 12 by enzymatic route. Fourier transform infrared, gas chromatography and nuclear magnetic resonance (NMR) spectroscopy techniques were used to determine the chemical composition of N,N-dimethyl fatty hydrazides. Proton NMR confirmed the product obtained were N,N-dimethyl fatty hydrazides.
Liquid chromatography-mass spectrometry was one of the most powerful methods for identification and detection of chemical structures of lipids. In this study, the cerebrosides molecular species from the sea cucumber Pearsonothria graeffei (P. graeffei) were high throughput identified by liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS). Cerebrosides were separated and purified by solid-phase extraction with chloroform-methanol solution. Precursor ion scan spectra and product ion scan spectra were obtained through auto MS/MS analysis in the positive scan. Cerebroside molecules were selected according to the neutral loss fragments of 180 Da, and then the structures were identified according to pairs of specific products of sphingoid bases and their precursor ions. Eighty-nine cerebrosides molecular species were identified, large amounts of d17:1-C22:0h, t17:0-C24:1h, d17:1-C24:1h, d17:1-C23:0h, d17:1-C22:0 and d17:1-C23:0 were present which have hardly found in mammal. There were 13 classes of long-chain base (LCB), and the ratio of phytosphingosines and sphingosines was roughly 1:9, in which two of the most common LCBs were d17:1 and d18:1. The carbon numbers of fatty acids (FAs) were mainly 18~24, while 24 carbon fatty acids were predominant. The ratio of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) was about 2:3, and the percentage of hydroxy fatty acid (HFA) was over 60%. The ratio of non-hydroxylated fatty acid (NFA)/HFA was also approximately 2:3. LC-Q-TOF-MS analysis should be useful for the structure determination of diverse cerebrosides molecular species. Meanwhile, this method provided a basis for structure-activity relationship studies and functional food development of the sea cucumber P. graeffei as well.
Bactericidal activities of benzalkonium chloride [also known as alkyldimethylbenzylammonium chloride (ADBAC)] containing nonionic surfactants such as methyl ester ethoxylates (MEE) with the alkyl group C8–C14 and oxyethylene (EO) group of average adduct number 3–15 were measured against Escherichia coli and Staphylococcus aureus. Sample solutions containing MEE in the vicinity of the critical micelle concentration exhibited a dramatic decrease in viable bacterial counts. MEE with an alkyl group of C12 and an oxyethylene group of lower adduct number exhibited little viable bacterial counts than those having higher EO adduct numbers. MEE with reduced EO adduct numbers increased fluorescence intensity in E. coli using the viability stain SYTO 9. Our results show that MEE molecules with low EO adduct numbers exhibited bactericidal activity by increasing the permeability of the E. coli cell membrane. Sample solution containing ADBAC and MEE molecules with lower EO adduct numbers also displayed higher zeta potentials. Moreover, ADBAC molecules incorporated into micelles of MEE with lower EO adduct numbers were adsorbed onto the surface of E. coli, which augmented bactericidal activity.
Microalgae have become an important source of biomass for biodiesel production. In enzymatic transesterification reaction, the enzyme activity is decreased in presence of alcohols. The use of different acyl acceptors such as methyl/ethyl acetate is suggested as an alternative and effective way to overcome this problem. In this study, ethyl acetate was used for the first time in the enzymatic production of biodiesel by using microalga, Chlorella vulgaris, as a triglyceride source. Enzymatic conversion of such fatty acids to biodiesel was catalyzed by Novozym 435 as an efficient immobilized lipase which is extensively used in biodiesel production. The best conversion yield of 66.71% was obtained at the ethyl acetate to oil molar ratio of 13:1 and Novozym 435 concentration of 40%, based on the amount of oil, and a time period of 72 h at 40℃. The results showed that ethyl acetate have no adverse effect on lipase activity and the biodiesel amount was not decreased even after seven transesterification cycles, so ethyl acetate has a great potential to be substituted for short-chain alcohols in transesterification reaction.
Synthesis of optically pure δ-lactones by diastereomeric resolution was investigated. Amino acid derivatives, which can be obtained at a relatively low cost, were used as resolving agents. Six optically pure δ-lactones were efficiently synthesized using Cbz-L-alanine without other expensive resolving agents. Both enantiomers of δ-lactone obtained had over 98% enantiomeric excesses. This diastereomeric resolution is very efficient for the preparation of optically pure δ-lactones.
The solid acid Ferric-manganese doped tungstated/molybdena nananoparticle catalyst was prepared via impregnation reaction followed by calcination at 600°C for 3 h. The characterization was done using X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), X-ray fluorescence (XRF), Transmission electron microscope (TEM) and Brunner-Emmett-Teller surface area measurement (BET). Moreover, dependence of biodiesel yield on the reaction variables such as the reaction temperature, catalyst loading, as well as molar ratio of methanol/oil and reusability were also appraised. The catalyst was reused six times without any loss in activity with maximum yield of 92.3% ±1.12 achieved in the optimized conditions of reaction temperature of 200°C; stirring speed of 600 rpm, 1:25 molar ratio of oil to alcohol, 6 % w/w catalyst loading as well as 8 h as time of the reaction. The fuel properties of WCOME’s were evaluated, including the density, kinematic viscosity, pour point, cloud point and flash point whereas all properties were compared with the limits in the ASTM D6751 standard.
Polyols were synthesized from epoxidized natural oils and tetrahydrofuran through ring opening copolymerization catalyzed by Lewis acid. The properties of these polyols depend on the type of natural oils as well as the reaction conditions (monomer concentration, catalyst amount, reaction temperature and reaction time). These polyols were evaluated as a raw material for making polyurethane (PU) in order to understand the structure-property relationship between a natural oil and PU made from it. The tensile test analysis shows that the incorporation of natural oil moiety into the PU polymer network improves the elasticity of these PU samples when compared to a benchmark PU sample. In addition, the PU samples made from palm oil and soybean oil based polyols exhibit better tensile strength than benchmark PU. These polyols samples are suitable for making elastomeric PU, where high flexibility (high elongation at break) of PU is a common requirement.
Consumption of chicken meat and its products, especially sausage, have increased in recent years. However, this product is susceptible to microbial contamination during manufacturing, which compromises its shelf life. The flavoring and preservative activities of essential oils (EO) have been recognized and the application of these antimicrobial agents as natural active compounds in food preservation has shown promise. The aim of this study was to evaluate the effect of Ocimum basilicum and Origanum vulgare EO on Listeria monocytogenes and Salmonella Enteritidis strains in artificially inoculated samples of fresh chicken sausage. First, the minimal inhibitory concentration (MIC) of EO in vitro was determined. The sausage was prepared and kept at ± 4°C; then, the inoculation of individual bacteria was carried out. EO were added at 0.3%, 1.0% and 1.5%v/w. After 0, 5, and 24 hours, the most probable number method (MPN) was performed. Transmission electron microscopy (TEM) was used to view the damage caused by these EO on bacterial morphology and/or structure. Only the 1.5% concentration was effective in reducing L. monocytogenes. 0.3% of O. vulgare EO was able to reduce the MPN/g of Salmonella Enteritidis (2 log) after 5 hours trials. O. basilicum EO showed no effect on Salmonella after 5 hours, but decreased by 2 log after 24 hours. O. vulgare EO at 1% gave a greater reduction of S. Enteritidis at 5 hours, increasing or maintaining this effect after 24 hours. The results confirmed the potential benefits of use EO in control of foodborne pathogens.