Longtao Zhang

Protective Effects of Alkaloid Compounds from Nelumbinis Plumula on tert-Butyl Hydroperoxide-Induced Oxidative Stress

This study was conducted to investigate the effect of Nelumbinis Plumula total alkaloid (NPA) and its main alkaloid components on oxidative stress induced by tert-butyl hydroperoxide (t-BHP) in the human hepatocellular HepG2 cell line. According to HPLC analysis, several major alkaloid compounds such as liensinine, isoliensinine and neferine were present in NPA. The cytotoxic effects in 0.55 mM t-BHP-induced HepG2 cells were significantly inhibited by NPA and the major compound in NPA, neferine, showed the strongest activities. The protective effect of neferine against oxidative stress induced by t-BHP may be associated with decreased ROS formation, TBARS generation, LDH release and increased GSH levels, suggesting their involvement of the cytoprotective on oxidative stress. The effects were comparable with quercetin, which was used as positive control. Overall, total alkaloid and alkaloid compounds from Nelumbinis Plumula displayed a significant cytoprotective effect against oxidative stress. Further study is needed to elucidate the relationship between the chemical structures of the components in NPA and their protective effect on oxidative stress.

Medium Optimization and Fermentation Kinetics for κ-Carrageenase Production by Thalassospira sp. Fjfst-332

Effective degradation of κ-carrageenan by isolated Thalassospira sp. fjfst-332 is reported for the first time in this paper. It was identified by 16S rDNA sequencing and morphological observation using Transmission Electron Microscopy (TEM). Based on a Plackett–Burman design for significant variables, Box–Behnken experimental design and response surface methodology were used to optimize the culture conditions. Through statistical optimization, the optimum medium components were determined as follows: 2.0 g/L κ-carrageenan, 1.0 g/L yeast extract, 1.0 g/L FOS, 20.0 g/L NaCl, 2.0 g/L NaNO3, 0.5 g/L MgSO4·7H2O, 0.1 g/L K2HPO4, and 0.1 g/L CaCl2. The highest activity exhibited by Thalassospira sp. fjfst-332 was 267 U/mL, which makes it the most vigorous wild bacterium for κ-carrageenan production. In order to guide scaled-up production, two empirical models—the logistic equation and Luedeking–Piretequation—were proposed to predict the strain growth and enzyme production, respectively. Furthermore, we report the fermentation kinetics and every empirical equation of the coefficients (α, β, X0, Xm and μm) for the two models, which could be used to design and optimize industrial processes.

Ultrasound-Assisted Rehydration of Dried Sea Cucumber (Stichopus japonicus) – Kinetics

Abstract Sea cucumbers are popular traditional tonic foods in Asia and the Middle East and are often dried for storage or sale. Rehydration of dried sea cucumber is a necessary step before further processing. The kinetics for ultrasound-assisted rehydration were mathematically described using mechanistic (Fick’s diffusion) and empirical (Peleg’s equation, Weibull model) models. The effective diffusivities of water transport with ultrasound were in the range of 0.182 mm2 min–1–0.197 mm2 min–1, which was greater than the value of the control, at 0.179 mm2 min–1, considering Fick’s diffusion. Peleg’s equation was concluded to be the best model to predict the ultrasound-assisted rehydration of dried sea cucumber. Its rehydration efficiency was increased 16-fold by ultrasound and rehydration time was reduced up to 45 h, the sea cucumbers did not show any negative effects on their texture properties after rehydration.

Purification and Characterisation of κ-Carrageenan Oligosaccharides Prepared by κ-Carrageenase from Thalassospira sp. Fjfst-332

κ-Carrageenan oligosaccharides (KCOs) are promising agents for treating inflammatory diseases. However, the lack of purification and structural elucidation of KCOs has limited structure-function evaluation. In this study, using a system coupling medium pressure liquid chromatography (MPLC) with an evaporative light scattering detector (ELSD), four types of KCOs were separated. The total yield of the four KCO powders was ∼5.02% after purification (KCOs/κ-carrageenan, w/w). Their structural identities were characterised by ESI-MS, CID-MS/MS and NMR, as κ-neocarrabiose (α-DA-1,3-G4Srα/β), κ-neocarratetraose (α-DA-1,3-β-G4S-1,4-α-DA-1,3-G4Srα/β), κ-neocarrahexaose (α-DA-1,3-β-G4S-1,4-α-DA-1,3-β-G4S-1,4-α-DA-1,3-G4Srα/β) and heterozygous κ/ι-neocarrahexaose (α-DA/DA2S-1,3-β-G4S-1,4-α-DA-1,3-β-G4S-1,4-α-DA-1,3-G4Srα/β). KCOs showed no cytotoxicity in RAW264.7 macrophages, and the anti-inflammatory activity was closely correlated with the degree of polymerisation and the number of sulfated groups. κ/ι-Neocarrahexaose exhibited the highest inhibition of ROS (Reactive Oxygen Species) production in LPS-induced RAW264.7 macrophages. The MPLC-ELSD system provides a platform for large-scale fabrication of purified KCOs and affords a route to these compounds that may regulate immune defense.

Structural characteristics and prebiotic effects of Semen coicis resistant starches (type 3) prepared by different methods.

In order to investigate the effects of different preparation methods on Semen coicis resistant starch, the structural properties and prebiotic effects of autoclaving treatment-purified S. coicis resistant starch (GP-SRS3), ultrasonic-autoclaving treatment-purified S. coicis resistant starch (UP-SRS3), enzyme-autoclaving treatment-purified S. coicis resistant starch (EP-SRS3) and microwave-moisture treatment-purified S. coicis resistant starch (MP-SRS3) were studied compared to high-amylose maize starch (HAMS). Fourier transform infrared spectroscopy and Solid-state 13C NMR spectroscopy showed all of SRS3 displayed B-type crystallite structure, furthermore, MP-SRS3 and UP-SRS3 showed higher degree of ordered structure and degree of double helical structure compared to other samples. Field emission scanning electron microscopy showed MP-SRS3 displayed deeply layered strips and UP-SRS3 exhibited some cavities. Moreover, S. coicis resistant starch could promote the growth of Bifidobacteria adolescentis better compared to high-amylose maize starch, among these samples. MP-SRS3 exhibited best prebiotic effect, which was possible attributed to its rough surface and double helix structure. B. adolescentis displayed a higher survival rate to the simulated gastrointestinal tract environment in SRS3 medium than that in high-amylose maize starch medium, especially MP-SRS3 and UP-SRS3, which partly contributed to its strips and cavities. Overall, MP-SRS3 could be regarded as a potential prebiotic to promote the growth of B. adolescentis for its structural trait.

The synthesis and characterization of a xanthan gum-acrylamide-trimethylolpropane triglycidyl ether hydrogel

To improve the thermal stability and adsorption performance, xanthan gum was modified with acrylamide and trimethylolpropane triglycidyl ether (TTE). The modified xanthan gum (XGTTE) was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractogram (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The characteristic peaks at 3449, 1655, 1611 and 1420 cm-1 in the FT-IR confirm the modification. The XGTTE crystal grew well upon addition of TTE. The XRD and DSC data revealed that the XGTTE enhanced its thermal stability. Analysis of SEM revealed that the grafting introduced major changes on the microstructure making it porous and resulting in the adsorption of crystal violet (CV) with flocculation. The CV adsorption capacity of the hydrogel with different dosages of TTE (XGTTE2, XGTTE3, XGTTE4, XGTTE5 and XGTTE6) were between 28.13 with 35.12 mg/g. In addition, the adsorption capacity, thermal stability, and swelling property of XGTTE4 were the best.