Metal cation-induced conformational changes of soybean protein isolate/soybean soluble polysaccharide and their effects on high-internal-phase emulsion properties.

BACKGROUND: Metal ions commonly inevitably appear in food products and have adverse effects on high-internal-phase emulsions (HIPEs) foods, but conformational conversion of soybean protein isolate (SPI)/soybean soluble polysaccharide (SSPS) on the interface layer of HIPEs influenced by different metal ions has rarely been reported. RESULTS: Here, the conformational conversion of SPI/SSPS induced by Na+ , K+ , Ca2+ , Mg2+ and Fe3+ ions and its effects on HIPEs were investigated. After adding the ions to SPI and SPI/SSPS dispersions, the particle size and zeta potential results showed different degrees of flocculation; the zeta potential and Fourier transform infrared spectra indicated that SPI and SPI/SSPS changes in structure involve electrostatic interactions and hydrogen bonding. Moreover, Raman spectra showed that the content of ß-sheet of SPI/SSPS HIPEs increased with the addition of Ca2+ , Mg2+ and Fe3+ , suggesting that SPI molecules at the interface formed a more orderly structure. The ultraviolet and fluorescence results showed that the hydrophobic environment of tryptophan and tyrosine residues inside protein molecules played a vital role in the emulsifying stability of SPI. CONCLUSION: These findings suggested that the SPI/SSPS complexes for food applications were not susceptible to ions, thus ensuring complex stability, showing potential for commercial application in the production of emulsions. © 2023 Society of Chemical Industry.

Improvement in texture and color of soy protein isolate gel containing capsorubin and carotenoid emulsions following microwave heating.

The effects of microwave heating on the properties and pigment release of soybean protein isolate (SPI) emulsion gel and hydrogel were investigated. The properties of the samples were analyzed by rheology and texture. The results showed that the hardness of the emulsion gel was lower than that of the hydrogel, but the cohesiveness was the opposite. The hydrogen bonding and electrostatic interaction between SPI and soybean soluble polysaccharide (SSPS) enhanced the thermal stability of the gel, and the enthalpy values were the lowest. In addition, a chroma meter was used to assess the slow-release effect of pigment, with results indicating that the emulsion gel was more red and yellow than the hydrogel; the values of a* and b* were reduced with the extension of heating time, indicating that the emulsion had a good protective effect on carotenoids and capsorubin, which was helpful to the application of the pigment in food.

Application of soy protein isolate fiber and soy soluble polysaccharide non-covalent complex: A potential way for pH-triggered release.

The non-covalent interactions between protein and polysaccharide have the potential to design responsive materials. In this study, soy protein isolate fiber/soy soluble polysaccharide (SPIF/SSPS) non-covalent complex was used to create an emulsion, and the pH-response performance was evaluated by investigating their microstructure, interfacial properties, and stability at pH values of 2.0-10.0. The SPIF/SSPS complex was relatively stable at pH 2.0 and 4.0, and the corresponding emulsions had uniform droplets that showed outstanding storage stability after 21 days. However, the SPIF/SSPS complex was dissociated gradually with the elevation of pH, especially under alkaline condition, that caused the flocculation and coalescence in emulsion. This phenomenon not only relate to electrostatic repulsion, but also relate to the disintegration of SPIF. Furthermore, the encapsulated curcumin is released rapidly from emulsion when the pH increased above 6.0. This research may provide an outstanding pH-response strategy that have the potential for pH-triggered release.

Tunable arrangement of hydrogel and cyclodextrin-based metal organic frameworks suitable for drug encapsulation and release.

The present study focused on the integration of beta-cyclodextrin based metal-organic frameworks (ß-CDMOF) with polymer to obtain hybrid materials with advantageous properties compared to traditional single-component polymers or metal-organic frameworks (MOF) matrixes. We fabricated two complexes with different morphology and structure. During the in situ growth of ß-CDMOF around the hydrogel, potassium ions on polysaccharides gradually dissociated to participate in the growth of crystals, while other potassium ions on the carboxylic acid groups provided bridges between crystals and hydrogel, forming a necklace-shaped complex (SHPs@ß-CDMOF). Hydrogen bonding and coordination interactions between ß-CDMOF and hydrogel are present in a dendritic sandwich-shaped complex (ß-CDMOF@SHPs). Furthermore, using the hydrophobic molecule curcumin as a model drug, we have demonstrated that SHPs@ß-CDMOF and ß-CDMOF@SHPs hybrid materials stabilize the included drug and have potential for controlled drug release. Collectively, the integration of MOF with polymer holds a great promise for drug delivery applications.

Characterization of the structure and properties of the isolating interfacial layer of oil-water emulsions stabilized by soy hull polysaccharide: Effect of pH changes.

The effect of pH on the microstructure and properties of the soy hull polysaccharide interfacial layer was determined. The particle size at pH 2.0 was the largest (36.7 µm), whereas the absolute ζ-potential was the smallest. The protein content was the lowest at pH 2.0 and 9.0 and peaked around pH 4.0-5.0 (77.7%). The ordered secondary protein structure content under low pH conditions was greater than that under high pH conditions and the stability of the interfacial layer was higher at high pH, whereas the emulsion viscosity decreased by two orders of magnitude between pH 2.0 and 9.0. It appears that low pH reduced the thermal stability and increased the apparent viscosity of the emulsion by increasing the structural order of the protein in the interfacial layer. These findings lay the foundation for future work to reveal the key components and characteristic structures of soy hull polysaccharide that affect interfacial stability.

Fabrication and emulsifying properties of non-covalent complexes between soy protein isolate fibrils and soy soluble polysaccharides.

Non-covalent complexes (SPIF/SSPS) of soy protein isolate fibrils (SPIF) and soy soluble polysaccharides (SSPS) were fabricated and used to stabilize oil-in-water (O/W) emulsions. FT-IR spectroscopy and zeta potential results demonstrated that the interactions between SPIF and SSPS mainly include hydrogen bonding and electrostatic interactions. The presence of SSPS decreased the particle size and surface hydrophobicity of SPIF, resulting in a decrease and redshift of the fluorescence intensity. During the interfacial adsorption process, SPIF/SSPS complexes had lower diffusion and penetration rates compared with pure SPIF because of their hydrophilic region, but the molecular reorganization rate increased. Emulsions stabilized with the SPIF/SSPS complex at 5 : 5 (i.e., 1 : 1) ratio had both an excellent emulsifying activity index (EAI) of 26.17 m2 g-1 and an excellent emulsifying stability index (ESI) of 93.01%, as well as the smallest emulsion droplet particle size of 1.74 µm. Meanwhile, no flocculation was observed in this emulsion which is attributed to the sufficient steric stabilization provided by the hydrophilic SSPS. After three weeks of storage, there was no phase separation observed in the emulsions stabilized by SPIF/SSPS complexes in 5 : 4 and 5 : 5 ratios and the Turbiscan stability indices were 17.86 and 15.14, respectively, much lower than the other emulsion formulations tested.

Application of traditional Chinese medicine preparation in targeting drug delivery system.

Targeting drug system (TDS) or targeted drug delivery system (TDDS) is a new kind of drug delivery system which could make drug to be directly concentrated on the target site with high curative effects and low side-effects. As the quintessence of Chinese culture, traditional Chinese medicine (TCM) has a large advantage in many disease clinical treatments, especially in cancer, hypertension and many other intractable diseases owing to their low toxicity and side-effects relative to western medicine. This article reviews literatures on development of TCM-targeted preparations which were published in the past 10 years. TDS including active-targeting, passive-targeting and physical-chemical-targeting preparations were introduced through domestic and overseas literatures to reveal the unique advantages of TCM-targeting preparations in drug delivery system. In this article, we have reviewed some kinds of TCM-targeting preparations and indicated that great attention should be paid to the research on the TCM-targeting preparations.

Hydroxypropyl-ß-cyclodextrin grafted polyethyleneimine used as transdermal penetration enhancer of diclofenac sodium.

The objective of this investigation was to develop a novel cationic polymer, hydroxypropyl-ß-cyclodextrin grafted polyethyleneimine (HP-ß-CD-PEI1800), as a penetration enhancer, and evaluate its viability on improving transdermal delivery of diclofenac sodium. In this study, HP-ß-CD-PEI1800 was characterized by (1)H NMR and DSC methods, respectively. The hydrophilic drug diclofenac sodium was chosen as model drug, and the transdermal permeation enhancement of HP-ß-CD-PEI1800 was estimated in vitro by using Franz diffusion cells fitted with mouse dorsal skins, the in vivo kinetics of diclofenac sodium was analyzed by high-performance liquid chromatography (HPLC). The cumulative drug content deposited in epidermis and dermis was measured at the pre-determined time point of 3, 6, and 9h, and the permeation profile was significantly higher than that of the control groups. In addition, the cytotoxicity and skin irritation of enhancer was evaluated by MTT assay and histological examination, respectively, and the results indicated that the polymer we prepared were non-toxic and non-irritant after exposure to skins. All the results suggested that HP-ß-CD-PEI1800 could be a safe and efficient penetration enhancer of diclofenac sodium.

Knowledge, attitudes and practices concerning self-medication with antibiotics among university students in western China.

OBJECTIVES: To evaluate the knowledge, attitude and behaviours of university students on the use of antibiotics. METHODS: A knowledge-attitude-practice questionnaire was developed and distributed to undergraduate students of Xi'an Jiaotong University, comprising 18 schools/colleges in Shaanxi Province, western China. Chi-square test and logistic regression analysis were applied to identify risk factors associated with self-medication with antibiotics. RESULTS: Of the 731 respondents (response rate = 73.1%), 294 (40.2%) had self-medicated with antibiotics in the past 6 months. Most of the antibiotics (59.2%) for self-medication were purchased without prescription in retail pharmacies. The median score of students' knowledge about antibiotics was 4 (IQR: 3-6) of a maximum possible score of 10. Students had moderately accurate beliefs towards antibiotics. More than half of the students (56.5%) were storing antibiotics frequently. During self-medication, 16.7% of students claimed to have experienced adverse reactions, and 30.6% had used antibiotics to prevent common colds. The majority preferred to use broad-spectrum antibiotics, and nearly half preferred intravenous antibiotics. Over 44% of students had changed antibiotic dosage, and 36.5% had switched to another antibiotic during the treatment course. Logistic regression analysis identified college and home town as independent risk factors for self-medication with antibiotics (P < 0.01). CONCLUSIONS: Undergraduate students had inadequate knowledge, moderately accurate beliefs and inappropriate practices concerning antibiotics, and a high rate of self-medication. This highlights the need for focused educational intervention and stricter governmental regulation concerning antibiotic use and sale in retail pharmacies.

Pharmacokinetic and anti-inflammatory effects of sanguinarine solid lipid nanoparticles.

The sanguinarine (SG) was studied for its pharmacokinetic and anti-inflammatory activities with prepared solid lipid nanoparticles (SLNs). The sanguinarine solid lipid nanoparticles (SG-SLNs) were prepared by film-ultrasonic dispersion method and the entrapment efficiency of SG was higher at 75.6 %. The drug release profile of SG was examined in pH 7.4 PBS and 85 % of the SG loaded in SLNs was gradually released during 24 h. We used mice endotoxin shock model which was induced by lipopolysaccharide (1 mg/kg) to examine the anti-inflammatory function of SG-SLNs. Healthy Kunming mice were administered orally with saline, SG (10 mg/kg), and SG-SLNs (10 mg/kg), respectively, at 12 and 1 h before lipopolysaccharide (LPS) injection. Mice were sacrificed at 1 and 6 h, respectively, and blood was collect through the venous sinus to access inflammatory mediators. Pharmacokinetic studies proved that the AUC(0→24) and C(max) of SG-SLNs were significantly increased compared that of SG. SG-SLNs revealed significant anti-inflammatory effects through inhibition of LPS-induced tumor necrosis factor-alpha level, interleukin 6 level, and nitric oxide production in serum. Therefore, it can be concluded that SG-SLNs led to a better oral bioavailability.

Synthesis and α-glucosidase inhibitory activity evaluation of N-substituted aminomethyl-ß-d-glucopyranosides.

A series of N-substituted 1-aminomethyl-ß-d-glucopyranoside derivatives was prepared. These novel synthetic compounds were assessed in vitro for inhibitory activity against yeast α-glucosidase and both rat intestinal α-glucosidases maltase and sucrase. Most of the compounds displayed α-glucosidase inhibitory activity, with IC50 values covering the wide range from 2.3µM to 2.0mM. Compounds 19a (IC50=2.3µM) and 19b (IC50=5.6µM) were identified as the most potent inhibitors for yeast α-glucosidase, while compounds 16 (IC50=7.7 and 15.6µM) and 19e (IC50=5.1 and 10.4µM) were the strongest inhibitors of rat intestinal maltase and sucrase. Analysis of the kinetics of enzyme inhibition indicated that 19e inhibited maltase and sucrase in a competitive manner. The results suggest that the aminomethyl-ß-d-glucopyranoside moiety can mimic the substrates of α-glucosidase in the enzyme catalytic site, leading to competitive enzyme inhibition. Moreover, the nature of the N-substituent has considerable influence on inhibitory potency.

A new series of N2-substituted-5-(p-toluenesulfonylamino)phthalimide analogues as α-glucosidase inhibitors.

Several members of a new family of non-sugar-type α-glycosidase inhibitors, bearing a 5-(p-toluenesulfonylamino)phthalimide moiety and various substituent at the N2 position, were synthesized and their activities were investigated. The newly synthesized compounds displayed different inhibition profile towards yeast α-glycosidase and rat intestinal α-glycosidase. Almost all the compounds had strong inhibitory activities against yeast α-glycosidase. Regarding rat intestinal α-glycosidase, only analogs with N2-aromatic substituents displayed varying degrees of inhibitory activities on rat intestinal maltase and lactase and nearly all compounds showed no inhibition against rat intestinal α-amylase. Structure-activity relationship studies indicated that 5-(p-toluenesulfonylamino)phthalimide moiety is a favorable scaffold to exert the α-glucosidase inhibitory activity and substituents at the N2 position have considerable influence on the efficacy of the inhibition activities.

[Study on chemical constituents of root bark of Discocleidion rufescens].

OBJECTIVE: To study the chemical constituents from root bark of Discocleidion rufescens. METHODS: Column chromatography and spectral analysis were used to isolate and identify the constituents. RESULTS: Ten compounds were obtained and identified from root bark of Discocleidion rufescens including beta-sitosterol (I), scopoletin (II), daucosterol (III), ricinine (IV), chrysophanol (V), aphyscion (VI), taraxerol (VII), pigenin (VIII), luteolin (IX), gallic acid (X). CONCLUSION: Ten compounds are isolated for the first time from root bark of Discocleidion rufescens. The monomer of Compounds II is isolated from this genus for the first time.

Influence of sodium dodecyl sulfate on swelling, erosion and release behavior of HPMC matrix tablets containing a poorly water-soluble drug.

The effect of sodium dodecyl sulfate (SDS) on the swelling, erosion and release behavior of HPMC matrix tablets was examined. Swelling and erosion of HPMC matrix tablets were determined by measuring the wet and subsequent dry weights of matrices. The rate of uptake of the dissolution medium by the matrix was quantified using a square root relationship whilst the erosion of the polymer was described using the cube root law. The extent of swelling decreased with increasing SDS concentrations in the dissolution medium but the rate of erosion was found to follow a reverse trend. Such phenomena might have been caused by the attractive hydrophobic interaction between HPMC and SDS as demonstrated by the cloud points of the solutions containing both the surfactant and polymer. Release profiles of nimodipine from HPMC tablets in aqueous media containing different concentrations of SDS were finally studied. Increasing SDS concentrations in the medium was shown to accelerate the release of nimodipine from the tablets, possibly due to increasing nimodipine solubility and increasing rate of erosion by increasing SDS concentrations in the dissolution medium.