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Aims To investigate the capability, properties, and molecular mechanism of inulin fermentation by lactic acid bacteria (LAB) from Sichuan pickle. Methods and results A total of 79 LAB strains were purified from 30 aged Sichuan pickle brine samples, and only 21 Lactiplantibacillus plantarum strains (26.58%, 21/79) derived from 15 samples grew well through utilizing inulin as a carbon source. The fermentation tests through using long-chain inulin (lc-inulin) as a carbon source showed that only 6 L. plantarum strains grew well, while other 15 strains could only utilize short-chain oligofructose (FOS), and thin-layer chromatography analysis evidenced a strain specificity of inulin consumption patterns. Lactiplantibacillus plantarum YT041 is a vigorous inulin fermenter, and whole genome sequencing data revealed that sacPTS1 and fosRABCDXE operons might be associated with the fermentation of FOS and lc-inulin, respectively. Conclusions The phenotype of inulin consumption is commonly present in LAB from Sichuan pickle, which is strain-specific and largely depends on their specific ecological niche and degree of polymerization.

Background Phenotypic switching of vascular smooth muscle cells (VSMCs) plays a key role in atherosclerosis. Long noncoding RNA ANRIL (lncRNA-ANRIL) is critical in vascular homeostasis. Metformin produces multiple beneficial effects in atherosclerosis. However, the underlying mechanisms need to be elucidated. Methods and results Metformin increased lncRNA-ANRIL expression and AMPK activity in cultured VSMCs, and inhibited the phenotypic switching of VSMCs to the synthetic phenotype induced by platelet-derived growth factor (PDGF). Overexpression of lncRNA-ANRIL inhibited phenotypic switching and reversed the reduction of AMPK activity in PDGF-treated VSMCs. While, gene knockdown of lncRNA-ANRIL by adenovirus or silence of AMPKγ through siRNA abolished AMPK activation induced by metformin in VSMCs. RNA-immunoprecipitation analysis indicated that the affinity of lncRNA-ANRIL to AMPKγ subunit was increased by metformin. In vivo, administration of metformin increased the levels of lncRNA-ANRIL, suppressed VSMC phenotypic switching, and prevented the development of atherosclerotic plaque in Apoe-/- mice fed with western diet. These protective effects of metformin were abolished by infecting Apoe-/- mice with adenovirus expressing lncRNA-ANRIL shRNA. The levels of AMPK phosphorylation, AMPK activity, and lncRNA-ANRIL expression were decreased in human atherosclerotic lesions. Conclusion Metformin activates AMPK to suppress the formation of atherosclerotic plaque through upregulation of lncRNA-ANRIL.

Sichuan pickle is one of popular traditional fermented foods in China. However, the contamination of heavy metals in Sichuan pickle, particularly home-made Sichuan pickle and aged pickle brine, is little known. Therefore, the content of trace (Cr, Cu, and Zn) and toxic elements (As, Pb, and Cd) in Sichuan industrial pickle (SIP), Sichuan home-made pickle (SHP), and aged pickle brine collected from local markets and families in Sichuan province, respectively, was detected by inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) and the health risk was assessed by target hazard quotients including target hazard quotient (THQ) and total target hazard quotient (TTHQ). Consequently, the mean concentrations of Cr, Cu, Zn, As, Pb, and Cd were 0.122, 0.540, 2.516, 0.023, 0.015, and 0.106 mg/kg in SIP and 0.071, 0.364, 2.698, 0.014, 0.015, and 0.289 mg/kg in SHP, respectively, lower than the maximum allowable concentrations set by Chinese regulations, except for Cr and Cd in few samples. Principal component analysis of the heavy metal content could obviously distinguish between SIP and SHP. The content of As, Pb, and Cd in leaf pickles was significantly higher than that in pickles fermented with other types of vegetables. A significant enrichment of heavy metals in aged pickle brine over 10 years was observed, but pickle jars had no significant effect on heavy metal content in aged pickle brine. The intake of heavy metals through daily consumption of SIP and SHP was at a safe level, whereas the TTHQ of leaf pickle was 1.006, indicating a potential health risk. In conclusion, this study provided fundamental data for food safety assurance of Sichuan pickle. PRACTICAL APPLICATION: Sichuan pickle is one of popular traditional fermented foods in China. In the present study, we investigated the contamination of heavy metals in Sichuan pickles by detecting the content of Cr, Cu, Zn, As, Cd, and Pb in Sichuan industrial pickle, Sichuan home-made pickle, and aged pickle brine, and estimated the health risk to local residents. This study can provide a reference for the safety risk of Sichuan industrial and home-made pickle in terms of heavy metal contamination, and enhance the food safety in the processing, production, and consumption of Sichuan pickle in local families and pickle industry.

The detection of nitrite is of great significance because it is closely related to food safety. In this work, a rapid colorimetric method was developed for nitrite detection based on the reaction of propylene glycol alginate (PGA) gel interface. In the reaction of nitrite and 4-Aminoacetophenone, diazo compound formed, which could be further transformed to purplish red compound by reacting with N-(1-Naphthyl)ethylenediamine (NED). Nitrite exhibited a linear relationship with the grayscale of the gel interface in the range of 0.3-9 μg mL-1 with a detection limit of 0.3 μg mL-1. The method was applied to detect nitrite in four types of pickled vegetables with recovery of 80.9-119.02% and relative standard deviation of 0.11-6.73%. Notably, the detection process can be accomplished within 5 minutes. The proposed colorimetric method exhibited advantages of simplicity, quickness and sensitivity, showing potential application prospects for the real-time and on-site detection of nitrite in pickled vegetables.

Background: Dietary betaine intake was reported to associate with favorable profile of metabolic disorders. However, the role of circulating betaine in coronary artery disease (CAD) patients with dysglycemia is still unknown. The present study aimed to investigate the potential associations between plasma betaine levels and dysglycemia in CAD patients. Methods: Total 307 subjects were enrolled in the present study with 165 CAD patients (57 with dysglycemia and 108 with normal glycemia) and 142 age- and sex-matched controls (CON). Fasting plasma betaine was detected using liquid chromatography tandem mass spectrometry. Results: Plasma betaine was lower in normal glycemia CAD patients (28.29 (22.38–35.73) μM) compared with healthy controls (29.75 (25.32–39.15) μM), and was further decreased in CAD patients with dysglycemia (24.14 (20.84–30.76) μM, P Conclusion: Plasma betaine levels are independently and inversely associated with dysglycemia in CAD after adjustment for multiple factors, and may be useful for risk stratification of dysglycemia in CAD.

Choline is an important nutrient involved in multiple biosynthesis pathways. However, whether circulating choline levels are associated with the risk of hypertension (HTN) and artery stenosis in HTN remains unknown. We investigated the correlations of plasma choline with HTN and coronary artery injury and explored the utility of plasma choline as a diagnostic biomarker for HTN and artery stenosis. 193 HTN patients and 154 age- and sex-matched healthy controls (CON) were recruited in this study. Fasting plasma choline was detected using liquid chromatography tandem mass spectrometry. Choline levels were significantly higher in HTN without artery stenosis (HTN-AS) than CON (8.07 [7.19-9.24] μM vs 7.03 [6.21-8.13] μM, P < .01) group and were further upregulated in HTN with artery stenosis (HTN + AS) (8.63 [7.09-10.59] μM, P < .01) group. Patients with multivessel disease (MVD) also exhibited higher choline levels than those with single vessel disease (SVD) (8.64 [7.16-10.55] μM vs 8.04(6.74-9.38) μM, P < .01). Increased choline levels were independently associated with the risk of HTN (OR = 1.2, 95% CI: 1-1.45, P = .05), HTN + AS (OR = 1.27, 95% CI: 1.09-1.48, P < .01), and MVD (OR = 1.16, 95% CI: 1.02-1.31, P = .02) after adjustment for multiple risk factors. Receiver operating characteristic (ROC) analysis showed that choline had an area under curve (AUC) score of 0.69, 0.67, and 0.63 in determining HTN, HTN + AS, and MVD. In conclusion, higher choline levels were associated with increased risk of HTN and artery stenosis in hypertensive patients.

Sichuan pickle is a natural combination of probiotics and dietary fibers, in which a strain Lactiplantibacillus plantarum QS7T was found to be capable of efficiently metabolizing inulin. However, the underlying molecular mechanism of inulin consumption by the strain QS7T is unclear. Therefore, this study firstly investigated the metabolic characteristics of inulin in the strain QS7T, and the results showed it could grow very well on the medium containing inulin as a carbon source (maximum OD600 nm, 1.891 ± 0.028) and degrade both short-chain oligofructose and long-chain fructan components through thin layer chromatography analysis. Genomic sequencing and analysis revealed a high percentage of functional genes associated with carbohydrate transport and metabolism, particularly glycoside hydrolase (GH) genes responsible for hydrolysing carbohydrates, within the genome of the strain QS7T. Furthermore, comparative transcriptomic analysis of L. plantarum QS7T in response to inulin or glucose indicated that functional genes associated with inulin consumption including several genes encoding PTS sugar transporters and two predicted GH32 family genes encoding beta-fructofuranosidase and beta-fructosidase were significantly up-regulated by inulin compared to the gene expression on glucose. In conclusion, we obtained a mechanistic understanding of interplay between probiotic L. plantarum QS7T derived from Sichuan pickle and natural dietary fiber, inulin; totally two operons including a sacPTS1 operon responsible for metabolizing short-chain oligofructose primarily in the cytoplasm and a fos operon responsible for extracellularly degrading all moderate and long-chain fructan components linked to inulin consumption by L. plantarum QS7T.

Oolong tea is an important member in tea family, which claims for various health benefits such as preventing obesity and improving lipid metabolism. In this work, using pancreatic lipase (PL) functionalised magnetic nanoparticles (PL-MNPs) as solid phase extraction absorbent in combination with ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), we developed a method for rapid screening and identification of lipase inhibitors from oolong tea. Three PL ligands were selectively extracted and identified as (-)-epigallocatechin-3-O-gallate (EGCG), (-)-gallocatechin-3-O-gallate (GCG) and (-)-epicatechin-3-O-gallate (ECG). Their lipase inhibitory activities were significantly higher than those non-ligands. Structure-activity analysis revealed that the presence of a galloyl moiety in the structure was required for binding to PL-MNPs, and therefore, exhibiting a strong inhibition on the enzyme. Taking advantages of the specificity in enzyme binding and the convenience of magnetic separation, this method has great potential for fast screening of lipase inhibitors from natural resources.

A new extraction agent featuring dopamine self-polymerized on magnetic Fe3 O4 nanoparticles has been successfully synthesized and evaluated for the SPE of berberine from the extract of the traditional Chinese medicinal plant, Cortex Phellodendri. The nanoparticles prepared possessed a core-shell structure and showed super-paramagnetism. It was found that these polydopamine-coated nanoparticles exhibited strong and selective adsorption for berberine. Among the chemical components present in C. Phellodendri, only berberine was adsorbed by the nanoparticles and extracted by a following SPE procedure. Various conditions such as the amount of polydopamine-coated nanoparticles, desorption solvent, desorption time and equilibrium time were optimized for the SPE of berberine. The purity of berberine extracted from C. Phellodendri was determined to be as high as 91.3% compared with that of 9.5% in the extract. The established SPE protocol combined advantages of highly selective enrichment with easy magnetic separation, and proved to be a facile efficient procedure for the isolation of berberine. Further, the prepared polydopamine-coated magnetic nanoparticles could be reused for multiple times, reducing operational cost. The applicability and reliability of the developed SPE method were demonstrated by isolating berberine from three different C. Phellodendri extracts. Recoveries of 85.4-111.2% were obtained with relative standard deviations ranging from 0.27-2.05%.

Lotus (Nelumbo nucifera) leaves have been widely used in weight-loss foods to prevent obesity in China. In this work, a facile procedure based on ligand fishing was developed to isolate and identify lipase inhibitors present in lotus leaves. Highly stable and active lipase-Fe3O4 superparamagnetic nanoparticle conjugates (LMNPs) were prepared and used as baits. Two flavonoids in lotus leaf extract were found to bind to the baits and were identified as quercetin-3-O-β-d-arabinopyranosyl-(1→2)- β-d-galactopyranoside (1) and quercetin-3-O-β-d-glucuronide (4) based on electrospray ionization-mass spectrometric analyses. Their 50% inhibitory concentrations on lipase (IC50) were 52.9 ± 3.2 and 17.1 ± 1.5 μg/mL, respectively. In addition, they were found to significantly quench the fluorescence of lipase, suggesting their strong affinities with this enzyme, which was further evidenced by molecular docking. Ligand fishing based on LMNPs shows great power for fast screening and identification of lipase inhibitors present in edible and medicinal plants.

A new extraction agent featuring dopamine self-polymerized on magnetic Fe3 O4 nanoparticles has been successfully synthesized and evaluated for the SPE of berberine from the extract of the traditional Chinese medicinal plant, Cortex Phellodendri. The nanoparticles prepared possessed a core-shell structure and showed super-paramagnetism. It was found that these polydopamine-coated nanoparticles exhibited strong and selective adsorption for berberine. Among the chemical components present in C. Phellodendri, only berberine was adsorbed by the nanoparticles and extracted by a following SPE procedure. Various conditions such as the amount of polydopamine-coated nanoparticles, desorption solvent, desorption time and equilibrium time were optimized for the SPE of berberine. The purity of berberine extracted from C. Phellodendri was determined to be as high as 91.3% compared with that of 9.5% in the extract. The established SPE protocol combined advantages of highly selective enrichment with easy magnetic separation, and proved to be a facile efficient procedure for the isolation of berberine. Further, the prepared polydopamine-coated magnetic nanoparticles could be reused for multiple times, reducing operational cost. The applicability and reliability of the developed SPE method were demonstrated by isolating berberine from three different C. Phellodendri extracts. Recoveries of 85.4-111.2% were obtained with relative standard deviations ranging from 0.27-2.05%.

Using carboxyl functionalized silica-coated magnetic nanoparticles (MNPs) as carrier, a novel immobilized porcine pancreatic lipase (PPL) was prepared through the 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. Transmission electron microscopic images showed that the synthesized nanoparticles (Fe3O4-SiO2) possessed three dimensional core-shell structures with an average diameter of ~20 nm. The effective enzyme immobilization onto the nanocomposite was confirmed by atomic force microscopic (AFM) analysis. Results from Fourier-transform infrared spectroscopy (FT-IR), Bradford protein assay, and thermo-gravimetric analysis (TGA) indicated that PPL was covalently attached to the surface of magnetic nanoparticles with a PPL immobilization yield of 50mg enzyme/g MNPs. Vibrating sample magnetometer (VSM) analysis revealed that the MNPs-PPL nanocomposite had a high saturation magnetization of 42.25 emu·g(-1). The properties of the immobilized PPL were investigated in comparison with the free enzyme counterpart. Enzymatic activity, reusability, thermo-stability, and storage stability of the immobilized PPL were found significantly superior to those of the free one. The Km and the Vmax values (0.02 mM, 6.40 U·mg(-1) enzyme) indicated the enhanced activity of the immobilized PPL compared to those of the free enzyme (0.29 mM, 3.16 U·mg(-1) enzyme). Furthermore, at an elevated temperature of 70 °C, immobilized PPL retained 60% of its initial activity. The PPL-MNPs nanocomposite was applied in the enzyme inhibition assays using orlistat, and two natural products isolated from oolong tea (i.e., EGCG and EGC) as the test compounds.