Prebiotic saccharides polymerization improves the encapsulation efficiency, stability, bioaccessibility and gut microbiota modulation of urolithin A liposomes.

This work was to investigate the effect of four prebiotic saccharides gum arabic (GA), fructooligosaccharide (FOS), konjac glucomannan (KGM), and inulin (INU) incorporation on the encapsulation efficiency (EE), physicochemical stability, and in vitro digestion of urolithin A-loaded liposomes (UroA-LPs). The regulation of liposomes on gut microbiota was also investigated by in vitro colonic fermentation. Results indicated that liposomes coated with GA showed the best EE, bioaccessibility, storage and thermal stability, the bioaccessibility was 1.67 times of that of UroA-LPs. The UroA-LPs coated with FOS showed the best freeze-thaw stability and transformation. Meanwhile, saccharides addition remarkably improved the relative abundance of Bacteroidota, reduced the abundances of Proteobacteria and Actinobacteria. The UroA-LPs coated with FOS, INU, and GA exhibited the highest beneficial bacteria abundance of Parabacteroides, Monoglobus, and Phascolarctobacterium, respectively. FOS could also decrease the abundance of harmful bacteria Collinsella and Enterococcus, and increase the levels of acetic acid, butyric acid and iso-butyric acid. Consequently, prebiotic saccharides can improve the EE, physicochemical stability, gut microbiota regulation of UroA-LPs, and promote the bioaccessibility of UroA, but the efficiency varied based on saccharides types, which can lay a foundation for the application of UroA in foods industry and for the enhancement of its bio-activities.

Preparation of carboxymethylcellulose / ZnO / chitosan composite hydrogel microbeads and its drug release behaviour.

In this study, a novel carboxymethylcellulose / ZnO / chitosan (CMC / ZnO / Cs) hydrogel microbeads loaded with crosslinked porous starch / curcumin (CPS / Cur) were designed and prepared to improve the encapsulation efficiency of curcumin for drug delivery to specific sites. It was found that the total pore volume of crosslinked porous starch (CPS) was increased by 1150 % when compared to the native starch (NS), and the adsorption ratio of curcumin by CPS was enhanced by 27 % when compared to NS. Secondly, the swelling ratio of composite hydrogel microbeads was within 25 % in an acidic environment at pH 1.2, and the swelling ratio of hydrogel microbeads sharply increased to 320 % ~ 370 % at pH 6.8 and 7.4. In addition, the results of in vitro simulated release experiments showed that the released amount of hydrogel microbeads loaded with NS/Cur and CPS/Cur in SGF were within 7 % in simulated gastric fluid (SGF). The highest released amount of curcumin was 65.26 % for hydrogel beads loaded with CPS/Cur, which was 26 % lower than that of hydrogel microbeads loaded with Cur in simulated intestinal fluid (SIF). In simulated colonic fluid (SCF), the released amount of hydrogel microbeads loaded with CPS/Cur and Cur were 73.96 % and 91.69 %, respectively. In conclusion, pH-sensitive drug delivery system with good drug stability and bioavailability were successfully prepared with carboxymethylcellulose / ZnO / chitosan bead, suitable targeting drug delivery to the small intestine.

Pulsed electric field-assisted esterification improves the freeze-thaw stability of corn starch gel by changing its molecular structure.

The influence of pulsed electric field (PEF) combined with octenyl succinic anhydride (OSA) on the freeze-thaw stability of corn starch gel was investigated. After five freeze-thaw cycles, the syneresis value of OSA starch treated with PEF-assisted esterification for 15 min was lower by 29.5 %, while that of OSA starch without PEF treatment was lower by 10.17 %, compared to that of native starch. Low-field nuclear magnetic resonance data showed that the introduction of OSA groups greatly increased the water-holding capacity of starch. Results from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) showed that the PEF-assisted esterification markedly hindered the re-formation of the helical structure of starch during freeze-thaw cycles. Moreover, PEF-assisted esterification improved the viscoelastic properties of the starch gel. It is found that the freeze-thaw stability of the PEF-modified starch depends not only on the degree of substitution but also on the starch molecular fine structure. PEF-assisted OSA starch with a high degree of substitution, a low content of amylose, and a high content of short amylopectin chains were found to have high freeze-thaw stability. This study shows that PEF-assisted esterification is a promising technique that should be used for preserving the quality of frozen foods.

Succinylated whey protein isolate-chitosan core-shell composite particles as a novel carrier: Self-assembly mechanism and stability studies.

Single protein [whey protein isolate (WPI) or succinylated whey protein isolate (SWPI)] and composite particles of proteins with chitosan (CS) were tested for their ability to encapsulate and protect curcumin (CUR). Combining protein and CS resulted in changes in zeta-potential and surface hydrophobicity, particularly in the SWPI-H (high degree of succinylation, 90 %) and CS composite particle (H-CS). Furthermore, the secondary and tertiary structures were dramatically altered using Fourier transform infrared (FTIR), circular dichroism (CD), and X-ray diffraction (XRD). Scanning electron microscopy (SEM) and atomic force microscope (AFM) analyses revealed that H-CS exhibited a soft core-rigid shell morphology due to electrostatic interactions, hydrophobic interactions, and H-bond interactions. Fluorescence quenching results demonstrated that H-CS had a higher binding constant (K, 1.69 ×104 M-1) and encapsulation effectiveness (EE, 88.3 %) of CUR. Because of increased binding sites and steric hindrance, CUR was stabilized more effectively in H-CS in photostability and thermostability tests,. These results show that SWPI-CS composite particles can be utilized to build a protection system for water-insoluble nutritional supplements.

Inhibition of Biofilm Formation of Foodborne Staphylococcus aureus by the Citrus Flavonoid Naringenin.

Taking into consideration the importance of biofilms in food deterioration and the potential risks of antiseptic compounds, antimicrobial agents that naturally occurring are a more acceptable choice for preventing biofilm formation and in attempts to improve antibacterial effects and efficacy. Citrus flavonoids possess a variety of biological activities, including antimicrobial properties. Therefore, the anti-biofilm formation properties of the citrus flavonoid naringenin on the Staphylococcus aureus ATCC 6538 (S. aureus) were investigated using subminimum inhibitory concentrations (sub-MICs) of 5~60 mg/L. The results were confirmed using laser and scanning electron microscopy techniques, which revealed that the thick coating of S. aureus biofilms became thinner and finally separated into individual colonies when exposed to naringenin. The decreased biofilm formation of S. aureus cells may be due to a decrease in cell surface hydrophobicity and exopolysaccharide production, which is involved in the adherence or maturation of biofilms. Moreover, transcriptional results show that there was a downregulation in the expression of biofilm-related genes and alternative sigma factor sigB induced by naringenin. This work provides insight into the anti-biofilm mechanism of naringenin in S. aureus and suggests the possibility of naringenin being used in the industrial food industry for the prevention of biofilm formation.

Enhanced synthesis of succinylated whey protein isolate by pulsed electric field pretreatment.

The objective of this study was to investigate the feasibility of pulse electric field (PEF) as a pretreatment for whey protein isolate (WPI) before its succinylation. The degree of succinylation (DS) of WPI increased from 88.31% for native WPI to 93.45% for PEF-pretreated WPI (PWPI, initial pH 10.0) for the same succinic anhydride (SA) to WPI ratio (1:1). Fourier transform infrared spectroscopy and scanning electron microscopy analysis proved the successful succinylation of WPI. For PWPIs, the surface hydrophobicity, exposed sulphydryl, and total sulphydryl decreased, which indicates the occurrence of changes in protein structures with more hydrophilic groups and better protein dispersion. Moreover, PEF may expose more amino acid residues binding sites that are present inside the protein, which is more suitable for succinylation. Therefore, the PEF pretreatment of proteins can improve their efficient use that is expected to play a critical role in succinylation industry.

Pulsed electric field assisted modification of octenyl succinylated potato starch and its influence on pasting properties.

The physicochemical properties and structural changes of potato starch esterified with octenyl succinic anhydride (OSA) assisted with pulsed electric field (PEF) were investigated. Results showed that PEF treatment during esterification resulted in a significant modification of pasting properties. The pasting temperature at 2-6 kV/cm reduced by 7.6-15.1 °C for PEF-assisted OSA starches but only by 3 °C for OSA modified starch without PEF treatment as compared to that of native starch. PEF-assisted esterification could reduce the reaction time and improve the reaction efficiency over the control by 6.1-39.1 %. A novel schematic model on structure-functionality relationship for PEF-assisted OSA modified starch was proposed. Structural disorganizations of starch induced lower pasting temperature and paste viscosity. The results suggest that PEF could be a potential eco-friendly and cost-effective physical technique to prepare starch products with desired paste behaviors and to broaden its application area especially in papermaking and textile industries.

Impact of pulsed electric field treatment on drying kinetics, mass transfer, colour parameters and microstructure of plum.

The aim of the present study was to scrutiny the impact of pulsed electric field (PEF) as a pre-treatment method on the convective drying kinetics, cell disintegration, colours and microstructural changes of fresh plums. In this study, the PEF intensities of 1-3 kV/cm, pulses number 30 and 70 °C drying temperature was applied to detect the drying kinetics. The specific energy consumption generated by PEF treatment was 10-90 kJ/kg. It was explored that the cell disintegration index increased from 0.147 to 0.572 with increased electric field intensity from 1 to 3 kV/cm. Further, we found that high cell disintegration leads to increase in drying rate and shorten drying time. The rates of water diffusion coefficient also increase with increasing PEF intensity from 0.27 to 16.47 × 10-9 m2/s. PEF pre-treatment followed by convective drying results in enhanced lightness and chroma as compared to untreated plum. Furthermore, the microscopic analysis by scanning electron microscopy at 200 × revealed that the PEF treatment at 3 kV/cm had caused shrinkage in the plum tissues which might be responsible for higher diffusion rate of water in the plum. In this work was investigated that drying kinetics and mass transfer after PEF treatment to improve quality of dried plum.

Cinnamaldehyde inhibit Escherichia coli associated with membrane disruption and oxidative damage.

In this study, the antimicrobial mechanism of cinnamaldehyde (CIN) against Gram-negative Escherichia coli ATCC 25922 (E. coli) based on membrane and gene regulation was investigated. Treatment with low concentration (0, 1/8, 1/4, 3/8 MIC) of CIN can effectively suppress the growth of E. coli by prolonging its lag phase and Raman spectroscopy showed obvious distinction of the E. coli after being treated with these concentration of CIN. The determination of relative conductivity indicated that CIN at relatively high concentration (0, 1, 2, 4 MIC) can increase the cell membrane permeability, causing the leakage of cellular content. Besides, the content of malondialdehyde (MDA) and the activity of total superoxide dismutase (SOD) of E. coli increased with increasing treatment concentration of CIN, implying that CIN can cause oxidative damage on E. coli cell membrane and induce the increase of total SOD activity to resist this oxidative harm. Moreover, quantitative real-time RT-PCR (qRT-PCR) analysis revealed the relationship between expression of antioxidant genes (SODa, SODb, SODc) and treatment CIN concentration, suggesting that SOD, especially SODc, played a significant role in resistance of E. coli to CIN. The underlying inactivation processing of CIN on E. coli was explored to support CIN as a potential and natural antimicrobial agent in food industry.

Hydroxyl-related differences for three dietary flavonoids as inhibitors of human purine nucleoside phosphorylase.

In this work, the hydroxyl-related differences of binding properties and inhibitory activities of dietary flavonoids, namely chrysin, baicalein and apigenin against purine nucleoside phosphorylase (PNP) were investigated. It was found that the hydroxylation on position C4' of chrysin (→apigenin) mildly decreased the binding affinities for PNP, whereas on the position C6 of chrysin (→baicalein) significantly increased binding affinities. Comparatively, the hydroxylation on position C4' and C6 greatly improved their PNP inhibitory effects. The IC50 values of apigenin and baicalein were 6.09 × 10-5 M and 8.94 × 10-5 M, respectively, which is significantly lower than that of chrysin (2.13 × 10-4 M). Results from molecular modeling revealed that there are two binding sites, i.e. active site (major) and tryptophan site (minor) on PNP, and the binding of these flavonoids might induce a serious conformational destabilization of PNP as a result of altering the micro-environment and morphology by flavonoids.

Metabolic profiling of antioxidants constituents in Artemisia selengensis leaves.

This study aimed to evaluate the antioxidant potential of Artemisia selengensis Turcz (AST) leaves, a byproduct when processing AST stalk, and identify the antioxidant constituents by using HPLC-QTOF-MS(2). The total phenolics content (TPC), total flavonoids content (TFC) and antioxidant abilities of fractions resulted from the successively partition of chloroform, ethyl acetate and n-butanol were compared. Ethyl acetate fraction (EAF) exhibited the highest TFC (65.44 mg QuE/g fraction), n-butanol fraction (nBuF) showed the highest TPC (384.78 mg GAE/g fraction) and the best DPPH scavenging ability, ABTS(+) scavenging ability and reducing power. Totally, 57 compounds were identified or tentatively identified in nBuF and EAF, 40 of them were reported in AST for the first time. The major constituents in EAF were flavonoids, and the major constituents in nBuF were phenolic acids and organic acids. Thus, AST leaves might be a potential low-cost resource of natural antioxidants.

Response surface optimization and physicochemical properties of polysaccharides from Nelumbo nucifera leaves.

Dynamic high pressure microfluidization (DHPM)-assisted extraction (DHPMAE) of lotus (Nelumbo nucifera) leaves polysaccharides (LLPs) was optimized by response surface methodology. The optimal extraction conditions were: liquid/solid ratio of 35:1 (v/m, mL/g), processing pressure of 180 MPa, processed two times, extraction temperature of 76°C, extraction time of 50 min. Under the optimal extraction conditions, DHPMAE produced a higher polysaccharides yield (6.31%) than leaching (2.95%). Scanning electron microscope (SEM) analysis revealed that DHPM could reduce the particles size and make the surface more unconsolidated. The LLPs prepared by both methods showed similar FT-IR spectrum, and were consisted of the same monosaccharides, including rhamnose, fucose, arabinose, xylose, mannose, glucose and galactose. The content of each monosaccharide in extracts, however, was quite different. The average molecular weight of LLPs prepared by DHPMAE is 550 kDa, smaller than 578 kDa obtained by leaching. The LLPs prepared by DHPMAE exhibited stronger DPPH scavenging ability (IC50 value of 0.38 mg/mL), HO scavenging ability (IC50 value of 0.61 mg/mL) and reducing power. Therefore, DHPMAE can be a promising alternative to traditional extraction techniques for polysaccharides from plants, and lotus leaves might be a potential resource of natural antioxidants.

[Comparison between antitumor effect and chemical constituents of Huanglian Jiedu decoction and that of serum containing Huanglian Jiedu decoction].

OBJECTIVE: To make a comparison between the antitumor effect and the chemical constituents of Huanglian Jiedu decoction (HLJDT) and that of serum containing HLJDT. METHOD: Based on the established chromatographic fingerprint of HLJDT, analysis and comparison were made between the HPLC fingerprints of rat serum samples obtained after orally taking HLJDT and those of control rat serum samples. The different effects on NCI-H446 and Bel-74024 cancer cells from human were investigated in vitro using HLJDT and its serum. The inhibitory effects of HLJDT and its serum were observed by MTT assay. RESULT: Ten compounds of HLJDT and some metabolites were detected after oral administration of HLJDT, and however some main compounds of HLJDT were not detected in serum. Both HLJDT and its serum in different dosage groups could inhibit the proliferation of NCI-H446 and Bel-7402 cancer cells from human in a dose-dependent manner, but inhibitory grade was different in the two cancer cell lines. HLJDT had more inhibitory effect on Bel-7402 than on NCI-H446, on the other hand serum containing HLJDT had the same inhibitory effect on Bel-7402 and NCI-H446. CONCLUSION: The reason for inhibitory grade change was that the proportion of concentration of many compounds in serum containing HLJDT was different to that in HLJDT, which should be subject to thorough investigation so as to illuminate the pharmacology and active mechanism of HLJDT.

[Study on antitumor activities of huanglian jiedu decoction].

OBJECTIVE: To study the antitumor activity of Huanglian Jiedu decoction (HLJDT). METHOD: Antitumor activities were tested in mice with experimental tumor H22 in vivo, and the thymus index, spleen index and tumor inhibitory rate were evaluated. The effects on cancer cells from human were investigated in vitro using serum pharmacological approach. Swille, SPC-A-1, SGC-7901 and MCF-7 cancer cells were incubated in culture media containing serum from mice medicated with HLJDT. The inhibitory effects of HLJDT serum were observed by MTT assay. RESULT: HLJDT showed significant antitumor activities on H22 in mice. All of the HLJDT serum in different dosage groups could highly inhibit the proliferation of 4 cancer cell lines from human. CONCLUSION: The HLJDT can significantly inhibit the tumor H22 in mice in a dose-dependent manner, the drug serum has obvious anticancer effects against Swille, SPC-A-1, SGC-7901 and MCF-7.

[Qualitative and quantitative determination of the main components of huanglianjiedu decoction by HPLC-UV/MS].

AIM: To establish a comprehensive HPLC analytical method of Huanglianjiedu decoction. METHODS: This study was performed by HPLC-UV/MS to identify the chemical constituents of the whole and individual herbs of the "Huanglianjiedu decoction". Zorbax Extend C18 (150 mm x 4. 6 mm ID, 5 microm) column was used; the mobile phase was composed of acetonitrile (A) and water (B, with 0.5% acetic acid) with gradient elution; the flow rate was 1.0 mL x min(-1) and the column temperature was setup at 25 degrees C. The detection wavelength was 254 nm. RESULTS: The chromatogram of Huanglianjiedu decoction showed 21 main peaks. Peaks 1, 2, 5 and 18 were from Gardenia jasminoides Ellis, Peaks 8, 13, 14, 15, 16, 17, 19 and 21 from Scutellaria baicalensis Georgi. While 10 from Coptis chinensis Franch and 20 from Phellodendron amurense Rupr., Peaks 3, 4, 6, 9, 11 and 12 came from them together. Peak 7 presented in the chromatograms of the herbs except Gardenia jasminoides Ellis. By comparison of the retention time, the on-line UV spectra and MS spectra, 11 peaks were identified as 5 (geniposide), 9 (jatrorrhizine), 10 (coptisine), 11 (palmatine), 12 (berberine), 13 (baicalin), 15 (oroxin A), 17 (wogonoside), 19 (baicalein), 20 (obaculactone), 21 (wogonin), then eight of them were quantified by HPLC-UV. CONCLUSION: The method could represent the characteristics of Huanglianjiedu decoction, and it could be used to evaluate the quality and quantity of Huanglianjiedu decoction. It distinguished between Coptis chinensis Franch and Phellodendron amurense Rupr. by HPLC for the first time.