查找使用阿拉丁产品的科研文献

N-acetyl-L-cysteine functionalized nanostructured lipid carrier for improving oral bioavailability of curcumin: preparation, in vitro and in vivo evaluations

Cihui Tian,Sajid Asghar,Yifan Wu,Daddy Kambere Amerigos,Zhipeng Chen,Mei Zhang,Lining Yin,Lin Huang,Qineng Ping,Yanyu Xiao

The application of orally administered nanoparticles in the circulation system is limited by the secretion and shedding of intestinal tract mucous layer. In order to enhance mucoadhesion and mucus penetration of curcumin (Cur)-loaded nanostructured lipid carrier (NLC) after oral administration, a new multifunctional conjugate, N-acetyl-L-cysteine-polyethylene glycol (100)-monostearate (NAPG), was synthesized. Functionalized nanocarriers (Cur-NAPG-NLC) modified by different amounts of NAPG (the amounts of NAPG were 20, 50, and 100 mg) were prepared and investigated for in vitro and in vivo behavior. Mean particle sizes of 89–141 nm with negative zeta potential (−15 to −11 mV) and high encapsulation efficiency (EE, >90%) possessing spherical and stable nanocarriers were observed. Sustained drug release was also observed for the NAPG-NLC. In situ intestinal perfusion studies showed that with increasing the amount of NAPG increase absorption of Cur. In vivo oral pharmacokinetic evaluation suggested that the bioavailability of Cur in rats was proportional to the degree of functionalization of NLCs with NAPG. AUC0–t of Cur-NAPG100-NLC was improved by 499.45 and 116.89 folds as compared to that of Cur solution and unmodified Cur-NLC, respectively. In conclusion, NAPG modified NLC could be a promising drug delivery system for improving oral performance of BCS class IV drugs.

Contribution of l-theanine to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea during manufacturing processes

Xiangyang Guo,Chuankui Song,Chi-Tang Ho,Xiaochun Wan

l -Theanine, the most abundant amino acid in tea, is widely believed to be associated with the tea taste, however, its contribution to the formation of tea aroma is still unknown. Volatiles were determined and nitrogen-containing compounds formed during manufacturing processes were quantified. Lower levels of total sugar and l -theanine were detected in the Oolong tea product undergoing full fire processing (FFOT) suggesting that l -theanine probably involved in the volatile formation during manufacturing processes. Methylpyrazine and 2,5-dimethylpyrazine, two newly formed compounds in FFOT, together with other volatiles were successfully detected in a model thermal reaction of d -glucose and l -theanine (GT-MTR) but not detectable in thermal reactions with single d -glucose (G-MTR) or l -theanine (T-MTR). The concentration of 2,5-dimethylpyrazine increased significantly by adding additional l -theanine to 2nd roasted tea. Our study demonstrated that l -theanine, at least partly, contributed to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea.

Isolation and characterization of plant growth-promoting rhizobacteria and their effects on the growth of Medicago sativa L. under salinity conditions

Zhu Zhiyu,Zhang Huanhuan,Leng Jing,Niu Huanqing,Chen Xiaochun,Liu Dong,Chen Yong,Gao Nan,Ying Hanjie

Plant growth-promoting rhizobacteria are a group of free-living bacteria that colonize plant rhizosphere and benefit plant root growth, thereby increasing host plant to cope with salinity induced stress. The aim of this study was to (1) isolate and characterize auxin-producing bacteria showing a high plant growth-promoting (PGP) potential, and (2) evaluate the PGP effects on the growth of Medicago sativa L under salinity stress (130 mM NaCl). Of thirteen isolates, Bacillus megaterium NRCB001 (NRCB001), B. subtilis subsp . subtilis NRCB002 (NRCB002) and B. subtilis NRCB003 (NRCB003) had the ability to produce auxin, which ranged from 47.53 to 154.38 μg ml −1 . The three auxin-producing bacterial strains were shown multiple PGP traits, such as producing siderophore and NH 3 , showing ACC deaminase activity, solubilize phosphate and potassium. Furthermore, NRCB001, NRCB002, and NRCB003 could survive in LB medium containing 1750 mM NaCl. The three auxin-producing with salinity tolerance strains were selected for further analyses. In greenhouse experiments, when inoculated with NRCB001, NRCB002 and NRCB003, dry weight of alfalfa significantly ( P  < 0.05) increased by 24.1%, 23.1% and 38.5% respectively, compared with those of non-inoculated control seedlings under normal growth condition. When inoculated with NRCB002 and NRCB003, dry weight of alfalfa significantly ( P  < 0.05) increased by 96.9 and 71.6% respectively, compared with those of non-inoculated control seedlings under 130 mM NaCl condition. Our results indicated that NRCB002 and NRCB003 having PGP traits are promising candidate strains to develop biofertilizers, especially used under salinity stress conditions.

Epsilon-poly-l-lysine decorated ordered mesoporous silica contributes to the synergistic antifungal effect and enhanced solubility of a lipophilic drug

Yiyan Song,Ping Zhu,Yuan Wu,Li Tan,Wei Wei,Songqin Liu,Qing Huang,Jin Chen

The emergence of drug-resistant fungal strains remains a severe threat for the public health, which prompts strict restrictions on the uses of antifungal drugs. However, the majority of lipophilic fungistatic agents are poorly water soluble with a low oral adsorption characteristic posing challenges for the precise prescriptions. In this study, a natural antimicrobial cationic peptide of epsilon-poly- l -lysine (EPL) decorated ordered mesoporous silica (SBA-15) was facilely prepared for the efficient loading of antifungal itraconazole (ITZ) drugs. The characterized mesoporous SBA-15/EPL/ITZ composite exhibited remarkable antifungal performance against Aspergillus fumigatus as a model mold, which was attributed to synergistic antifungal activities of ITZ and EPL in the mesopores. Moreover, the in vitro release behaviors of ITZ in the composite nanoexcipients both in simulated gastric fluid and fasted state simulated intestinal fluid were studied. The observed release kinetics of ITZ demonstrated a contributing role of SBA-15/EPL to enhance the solubility of ITZ and thereby may promote its flux across the gastrointestinal epithelium, which is beneficial for the absorption of drugs. Additionally, SBA-15/EPL/ITZ composites showed desirable biocompatibility toward mammalian red blood cells, human cervical cancer cells (Hela) and human embryonic kidney cells (HEK-293T). Furthermore, the pharmacokinetic profiles of obtained nano-formulations were assessed in rats, among which the improved adsorption of SBA-15/EPL/ITZ composites (AUC 0–24h sum : 8381.7 nM·h) was identified compared with that of pure ITZ (525.1 nM·h) and the commercial drug of Sporanox (7516.6 nM·h). Collectively, the prepared SBA-15/EPL/ITZ provides an ecofriendly and integrated nanocomposite with enhanced solubility of lipophilic drugs to combat proliferations of infectious fungi.

The Solubility and Structures of Porcine Myofibrillar Proteins under Low-Salt Processing Conditions as Affected by the Presence of L-Lysine

Xiuping Li,Wenhui Wang,Shouyin Wang,Yuqing Shen,Jinfeng Pan,Xiuping Dong,Shengjie Li

This study aimed to investigate the presence ofL-lysine (Lys) on the solubility and structures of myofibrillar proteins (MFPs) at different ionic strengths. Porcine MFPs were incubated at 4 °C with various levels of ionic strengths (0.15, 0.3, or 0.6 M NaCl) with or without the presence of 20 or 40 mM Lys. After 24 h of incubation, MFP solubility and turbidity were determined, and the particle size distribution, circular dichroism spectra, and intrinsic tryptophan fluorescence of MFP were analyzed to obtain their secondary and tertiary structure. Results showed that the solubilization effects of Lys on MFPs are dependent on the ionic strength. Particularly, the presence of Lys could improve MFP solubility at 0.3 M, which resembles salt-reducing processing conditions. Concomitantly, the secondary and tertiary structures were observed to change as a result of the varying ionic strengths and the addition of Lys, including myofibril swelling, dissociation of myosin filaments, uncoiling of α-helix, and unfolding of the tertiary structure. The possible mechanisms underlying the solubilization effects of Lys on MFPs at low ionic strengths are discussed from the perspective of protein structural changes.Keywords:myofibrillar proteins;L-lysine;solubility;conformation;low salt

Unsaturated nitrogen-rich polymer poly(l-histidine) gated reversibly switchable mesoporous silica nanoparticles using “graft to” strategy for drug controlled release

Shengjun Mu,Yongjun Liu,Tianqi Wang,Jing Zhang,Dandan Jiang,Xiaoyue Yu,Na Zhang

A novel and intelligent pH-controlled system having an “on-off” switch based on poly( l -histidine) (PLH) and poly(ethylene glycol) (PEG) coated mesoporous silica nanoparticles (MSNs) (MSNs-PLH-PEG) was designed and evaluated for tumor specific drug release. The unsaturated nitrogen-rich polymer, PLH, which can change its solubility at different pH values, was employed for establishing the reversible “on-off” switch. In vitro drug release results demonstrated that MSNs-PLH-PEG has a pH-controlled “on-off” profile with the change of pH value between pH 7.4 and 5.0. Furthermore, in vitro cellular uptake study results showed that the entrapped drug could be efficiently released from MSNs-PLH-PEG under acidic endosome/lysosome. In vitro cell cytotoxicity and in vivo antitumor studies results indicated that sorafenib loaded MSNs-PLH-PEG exhibited good anti-proliferation and tumor growth inhibition effects. Haemolysis assay and histological analysis of MSNs-PLH-PEG showed negligible haemolysis activity and no visible tissue toxicity at the test dose. This study represents a promising and intelligent pH-controlled intelligent system for drug delivery and controlled release. Statement of Significance A novel pH-controlled intelligent and reversible “on-off” switch system based on poly( l -histidine) and poly(ethylene glycol) coated mesoporous silica nanoparticles (MSNs-PLH-PEG) by “graft to” synthesis method was constructed for tumor specific drug release. The unsaturated nitrogen-rich pH-sensitive polymer, PLH, which can change its solubility in different pH values, was employed as the reversible “on-off” switch in MSNs for the first time. The pH-controlled “on-off” switch manner was observed in the drug release results in vitro . In the in vivo antitumor studies, sorafenib loaded MSNs-PLH-PEG could effectively suppressed tumor growth in H22 tumor bearing mice. It is expected that the pH-controlled intelligent “on-off” switch system we designed holds remarkable promise and provides valuable strategy for possible applications in cancer therapy.

Idarubicin-loaded methoxy poly(ethylene glycol)-b-poly(l-lactide-co-glycolide) nanoparticles for enhancing cellular uptake and promoting antileukemia activity

Bin Liang,Na Li,Shuofei Zhang,Aihua Qi,Jianhua Feng,Weiwei Jing,Changcan Shi,Zhaipu Ma,Shenmeng Gao

Effect of l-histidine on the heat-induced aggregation of bighead carp (Aristichthys nobilis) myosin in low/high ionic strength solution

Ruichang Gao,Yanmin Wang,Jianlou Mu,Tong Shi,Li Yuan

In this study, the effects of l -histidine (L-His) on the aggregation of bighead carp ( Aristichthys nobilis ) myosin induced by heating in low (0.1) or high (0.5) ionic strength solutions were studied. The solubility of natural myosin was significantly enhanced by L-His both in low and high ionic strength solutions. More small particles are suspended in the heated solution containing L-His, inducing a higher solubility than that solution without L-His. The surface hydrophobicity of myosin in a low ionic strength solution containing L-His is higher than that of myosin without L-His. The results of morphology show that L-His induced myosin to form finer aggregates and a honeycomb-like network in a low/high ionic strength solution during heat treatment. These results demonstrate that L-His might disrupt the electrostatic property of unfolded myosin heat-induced through electrostatic binding with the exposed negatively charged amino acid residues, which might disarrange hydrophobic surfaces, resulting in weakening hydrophobic interactions, which ultimately suppresses the fierce aggregation of carp myosin.

A fluorescent biosensor based on quantum dot–labeled streptavidin and poly-l-lysine for the rapid detection of Salmonella in milk

Shuangyan Ding,Hailiang Hu,Xianglin Yue,Kaiwen Feng,Xiaoyu Gao,Qiuling Dong,Mingqi Yang,Ugur Tamer,Ganhui Huang,Jinsheng Zhang

ABSTRACT Salmonella , as a common foodborne pathogen in dairy products, poses a great threat to human health. We studied a new detection method based on quantum dots (QD). A fluorescent biosensor with multiple fluorescent signal amplification based on a streptavidin (SA) biotin system and the polyamino linear polymer poly- l -lysine (PLL) were established to detect Salmonella in milk. First, Salmonella was captured on a black 96-well plate with paired Salmonella mAb to form a double-antibody sandwich. Second, SA was immobilized on biotin-modified mAb by SA-biotin specific bond. Then, the biotin-modified polylysine (BT-PLL) was bound on SA and specifically bonded again through the SA-biotin system. Finally, water-soluble CdSe/ZnS QD-labeled SA was added to a black 96-well plate for covalent coupling with BT-PLL. The fluorescent signal was amplified in a dendritic manner by the layer-by-layer overlap of SA and biotin and the covalent coupling of biotinylated PLL. Under optimal conditions, the detection limit was 4.9 × 10 3 cfu/mL in PBS. The detection limit was 10 times better than that of the conventional sandwich ELISA. In addition, the proposed biosensor was well specific and could be used for detecting Salmonella in milk samples.

Effects of faba bean (Vicia faba L.) on fillet quality of Yellow River carp (Cyprinus carpio) via the oxidative stress response

Dongying Song,Yinghao Yun,Zijie He,Jiali Mi,Jiaxiang Luo,Min Jin,Qicun Zhou,Guoxing Nie

In order to further explain the fillet texture improvement of Yellow River carp ( Cyprinus carpio ) fed with faba bean ( Vicia faba L.), a three-month rearing trial was conducted to investigate fatty acid composition, antioxidant capacity, myofiber development, collagen deposition and transcriptome in white muscle of two farmed carp groups (One was fed only faba bean, the other was fed commercial diet). As a strong oxidant, faba bean changed fatty acids composition in white muscle, especially DHA and EPA, up-regulated the levels of reactive oxygen species (ROS) and down-regulated major antioxidant enzyme activities in the hepatopancreas and white muscle. Through the analysis of transcriptome and subsequent verification analysis, we speculated that the increase of ROS led to the decrease of myofiber diameter and collagen metabolism. This study provides a theoretical basis for further understanding the regulation of faba bean on fillet texture characteristic of Yellow River carp.

Synthesis of a mace-like cellulose nanocrystal@Ag nanosystem via in-situ growth for antibacterial activities of poly-L-lactide scaffold

Cijun Shuai,Xun Yuan,Wenjing Yang,Shuping Peng,Guowen Qian,Zhenyu Zhao

Antibacterial property for scaffolds is an urgent problem to prevent infections in bone repair. Ag nanoparticles possess excellent bactericidal activities, whereas their agglomeration restricts the full play of antibacterial property in scaffold. Herein, a mace-like nanosystem was constructed to improve their dispersion by in-situ growth of Ag nanoparticles on cellulose nanocrystal (CNC), which was labeled CNC@Ag nanosystem. Subsequently, the CNC@Ag nanosystem was introduced into poly-L-lactide (PLLA) scaffolds. Results demonstrated that the nanosystem uniformly dispersed in scaffold. The antibacterial tests demonstrated that the scaffolds possessed robust antibacterial activities against E. coli , with bacterial inhibition rate over 95%. Moreover, ion release behavior corroborated the scaffolds continuously released Ag + for more than 28 days, which benefited from the immobilization effect of CNC on Ag. Encouragingly, the mechanical properties of the scaffolds were remarkably higher than that of PLLA/CNC scaffolds, owing to the mace-like CNC@Ag nanosystem improved the load transfer efficiency in the scaffold.

An anthracenecarboximide fluorescent probe for in vitro and in vivo ratiometric imaging of endogenous alpha-L-fucosidase for hepatocellular carcinoma diagnosis

Xianfeng Hou,Jin Peng,Fang Zeng,Changmin Yu,Shuizhu Wu

Alpha-L-fucosidase (AFU) plays vital roles in some physiological processes that closely relate to several diseases. Herein, a ratiometric fluorescent probe for the alpha-L-fucosidase (AFU) assay based on a single fluorophore has been developed by functionalizing a new fluorophore platform (6-bromo-anthracenecarboximide) with an α-L-fucose group. AFU cleaves the α-L-fucose group from the probe molecule and remarkably alters its photophysical properties, thus realizing ratiometric detection of AFU. Due to the specificity and high efficiency of the enzymatic reaction, this probe can sensitively and selectively detect AFU in aqueous media and biological milieus with a detection limit of 0.0033 U mL−1. Moreover, the probe can be employed to monitor and spatially map endogenous AFU levels in a hepatocellular carcinoma (HCC) model of zebrafish. Hence, the probe holds significant promise for conducting pathological research on AFU-involved diseases.