Regulation and mechanism of organic selenium on quorum sensing, biofilm, and antioxidant effects of Lactobacillus paracasei.

Different organic compounds can have varying degrees of impact on the activity of Lactobacillus paracasei. The study focused on the impact and action mechanism of different organic selenium products on the bioactivity of two strains of L. paracasei. The growth, antioxidant activity, extracellular polysaccharide secretion, quorum sensing (QS), and biofilm formation of the strains before and after the addition of organic selenium crude products and three organic selenium standard were evaluated. The results showed that the addition of crude organic selenium promoted the various activities of the strain. l-selenocysteine had the strongest regulatory effect, with maximum GIM1.80 biofilm formation when it reached a critical concentration of 0.4 µg/mL; l-selenomethionine resulted in the highest activity of the signal molecule Auto inducer-2 of GDMCC1.155, when it reached a critical concentration of 0.4 µg/mL. The results of scanning electron microscopy demonstrated that the addition of organic selenium effectively improved the morphological structure of the two bacterial cells. Molecular docking revealed that the mechanism by which organic selenium regulates QS in Lactobacillus was achieved by binding two crucial receptor proteins (histidine protein kinase HKP and periplasmic binding protein LuxP) from specific sites. Furthermore, organic selenium products have a beneficial regulatory effect on the biological activity of L. paracasei. Overall, these findings provide a new alternative (organic selenium) for regulating the viability and beneficial activity of L. paracasei.

Development of a compound oral liquid containing herbal extracts and its effect on immunity and gastric mucosa.

Nowadays, consumers have an increasing demand for health products. In this study, an oral liquid was developed using a compound extract consisting of three herbal extracts (Dendrobium nobile Lindl., Lycium barbarum, and Puerariae lobatae Radix) because the compound extract (a combination of all three extracts) was superior to every single extract in promoting the phagocytic capacity of RAW264.7 macrophages and the proliferation ability of GES-1 cells. In this oral liquid, the dosage of the stabilizer and the sweetener was selected using a stability test and sensory quality evaluation. When 0.30% (m/v) xanthan gum and 0.20% (m/v) mogroside were added, the oral liquid had not only a good stability but also the highest sensory score for overall acceptability. The chemical composition analysis showed that the oral liquid had various functional ingredients including polysaccharides, phenols, alkaloids, and so forth. The immune-enhancing efficacy of the oral liquid was evaluated in BALB/c mice by measuring the levels of different immune indicators. The results indicated that the oral liquid obviously enhanced nonspecific and specific immunity. A rat model with ethanol-induced gastric ulcer was used to examine the protective effect of the oral liquid on the gastric mucosa and to explore the related mechanisms. The oral administration of the oral liquid for days significantly prevented the formation of gastric ulcer. This study provided an effective oral liquid that could enhance immunity and protect gastric mucosa.

Separation of phenolics from peony flowers and their inhibitory activities and action mechanism on bacterial biofilm.

Separation and enrichment of phenolics from peony flowers were performed to improve the anti-biofilm and antibacterial activities for the first time. Through several times of separation, the purity of phenolics components increased significantly, and the anti-biofilm and antibacterial activities of phenolics components against E. coli and S. aureus were also significantly improved. Finally, the phenolics of peony flowers in the eluent of silica gel column chromatography (PPF-ESGCC) were found to exhibit the highest anti-biofilm and antibacterial activities. The inhibition rates of PPF-ESGCC on biofilms of E. coli and S. aureus were 77.93%, and 87.03% respectively, at a very low concentration (1/2 MIC, 0.235 mg/mL). It was found that the biofilm inhibition was achieved by inhibiting their swimming, swarming, twitching motilities, exopolysaccharide (EPS) production, and quorum sensing (QS). Moreover, there was a positive dose-dependent relationship (r = 0.75 to 1) between the inhibition rates and concentrations of PPF-ESGCC during the critical biofilm-formation stage (1-3 days). Chemical composition analysis showed the PPF-ESGCC comprised of gallic acid, kaempferol-7-O-glucoside, and apigenin-7-O-glucoside. In conclusion, PPF-ESGCC exhibited strong inhibitory effect on biofilm formation and gallic acid, kaempferol-7-O-glucoside, and apigenin-7-O-glucoside might play a crucial role in inhibiting biofilm formation. Meanwhile, this study indicated that PPF-ESGCC, a new natural QS inhibitor and biofilm inhibitor, could be used as a novel intervention strategy to enhance the safety and quality of food.

Occurrence, biological activity and metabolism of 6-shogaol.

As one of the main bioactive compounds of dried ginger, 6-shogaol has been widely used to alleviate many ailments. It is also a major pungent flavor component, and its precursor prior to dehydration is 6-gingerol, which is reported to be responsible for the pungent flavor and biological activity of fresh ginger. Structurally, gingerols including 6-gingerol have a ß-hydroxyl ketone moiety and is liable to dehydrate to generate an α,ß-unsaturated ketone under heat and/or acidic conditions. The conjugation of the α,ß-unsaturated ketone skeleton in the chemical structure of 6-shogaol explicates its higher potency and efficacy than 6-gingerol in terms of antioxidant, anti-inflammatory, anticancer, antiemetic and other bioactivities. Research on the health benefits of 6-shogaol has been conducted and results have been reported recently; however, scientific data are scattered due to a lack of systematic collection. In addition, action mechanisms of the preventive and/or therapeutic actions of 6-shogaol remain obscurely non-collective. Herein, we review the preparations, biological activity and mechanisms, and metabolism of 6-shogaol as well as the properties of 6-shogaol metabolites.

Protective effects of polysaccharide from Dendrobium nobile against ethanol-induced gastric damage in rats.

Dendrobium nobile is a medicinal herb in traditional China and Southeast Asian countries. Employing a rat model of ethanol-induced gastric ulcer, we examined the protective effect of polysaccharide (JCP) extracted from Dendrobium nobile and explored the related mechanisms. Oral administration with 100mg/kg and 300mg/kg body weight JCP for days can significant prevent the formation of gastric ulcer. Moreover, JCP pretreatment could alleviate ethanol-induced histological damage, antioxidant activities, the level of epidermal growth factor, gastric concentration of prostaglandin E, and regulate the signaling pathways of mitogen-activated protein kinases and matrix metalloproteinases. This study investigated the ethanol-induced gastric ulcer protective effect of JCP for the first time, and elucidated that the protective mechanisms.

Antibacterial, Antibiofilm Effect of Burdock (Arctium lappa L.) Leaf Fraction and Its Efficiency in Meat Preservation.

First, the antibacterial, antibiofilm effect and chemical composition of burdock (Arctium lappa L.) leaf fractions were studied. Then, the efficiency of burdock leaf fractions in pork preservation was evaluated. The results showed that burdock leaf fraction significantly inhibited the growth and biofilm development of Escherichia coli and Salmonella Typhimurium. MICs of burdock leaf fractions on E. coli and Salmonella Typhimurium were both 2 mg/ml. At a concentration of 2.0 mg/ml, the inhibition rates of the fraction on growth and development of E. coli and Salmonella Typhimurium biofilms were 78.7 and 69.9%, respectively. During storage, the log CFU per gram of meat samples treated with burdock leaf fractions decreased 2.15, compared with the samples without treatment. The shelf life of pork treated with burdock leaf fractions was extended 6 days compared with the pork without treatment, and the sensory property was obviously improved. Compared with the control group, burdock leaf fraction treatment significantly decreased the total volatile basic nitrogen value and pH of the meat samples. Chemical composition analysis showed that the burdock leaf fraction consisted of chlorogenic acid, caffeic acid, p-coumaric acid, rutin, cynarin, crocin, luteolin, arctiin, and quercetin. As a vegetable with an abundant source, burdock leaf is safe, affordable, and efficient in meat preservation, indicating that burdock leaf fraction is a promising natural preservative for pork.

Metabolomics-Based Screening of Biofilm-Inhibitory Compounds against Pseudomonas aeruginosa from Burdock Leaf.

Screening of anti-biofilm compounds from the burdock leaf based on metabolomics is reported here. The crystal violet assay indicated 34% ethanol elution fraction of burdock leaf could completely inhibit biofilm formation of Pseudomonas aeruginosa at 1 mg·mL(-1). Then, the chemical composition of burdock leaf fraction was analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and 11 active compounds (chlorogenic acid, caffeic acid, p-coumaric acid, quercetin, ursolic acid, rutin, cynarin, luteolin, crocin, benzoic acid, and Tenacissoside I) were identified. Lastly, UPLC-MS analysis was employed to obtain the metabolic fingerprints of burdock leaf fractions before and after inhibiting the biofilm of Pseudomonas aeruginosa. The metabolic fingerprints were transformed to data, analyzed with PLS-DA (partial least squares discriminant analysis) and the peaks whose area was significantly changed were found out. Thus, 81 compounds were screened as potential anti-biofilm ingredients. Among them, rutin, ursolic acid, caffeic acid, p-coumaric acid and quercetin were identified and confirmed as the main anti-biofilm compounds in burdock leaf. The study provided basic anti-biofilm profile data for the compounds in burdock leaf, as well as provided a convenient method for fast screening of anti-biofilm compounds from natural plants.

Anti-diabetic activity of peony seed oil, a new resource food in STZ-induced diabetic mice.

This study was conducted to investigate the components of a new resource food in China, peony seed oil (PSO) by GC-MS (gas chromatography-mass spectrometry), its inhibitory effects on carbohydrate hydrolyzing enzymes in vitro and its anti-diabetic effects on mice induced by streptozotocin (STZ). The results showed that peony seed oil showed weak anti-α-amylase activity; however, strong anti-α-glucosidase activity was noted. The GC-MS analysis of the oil showed 9 constituents of which α-linolenic acid was found to be the major component (38.66%), followed by linoleic acid (26.34%) and oleic acid (23.65%). The anti-diabetic potential of peony seed oil was tested in STZ induced diabetic mice. Administration of peony seed oil and glibenclamide reduced the blood glucose level and the area under curve (AUC) in STZ induced diabetic mice. There were significant increases in body weight, liver glycogen content, serum insulin level, high-density lipoprotein cholesterol (HDL-C) and decreases in glycosylated hemoglobin (HbA1C), total serum cholesterol (TC), and triglyceride (TG) in test groups as compared to the untreated diabetic groups. In vivo antioxidant studies on STZ induced diabetic mice revealed the reduction of malondialdehyde (MDA) and increase of glutathione peroxides (GSH-px), superoxide dismutase (SOD), and glutathione (GSH). The results provided a sound rationale for future clinical trials of oral administration of peony seed oil to alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice.

Removal of caffeine from green tea by microwave-enhanced vacuum ice water extraction.

In order to selectively remove caffeine from green tea, a microwave-enhanced vacuum ice water extraction (MVIE) method was proposed. The effects of MVIE variables including extraction time, microwave power, and solvent to solid radio on the removal yield of caffeine and the loss of total phenolics (TP) from green tea were investigated. The optimized conditions were as follows: solvent (mL) to solid (g) ratio was 10:1, microwave extraction time was 6 min, microwave power was 350 W and 2.5 h of vacuum ice water extraction. The removal yield of caffeine by MVIE was 87.6%, which was significantly higher than that by hot water extraction, indicating a significant improvement of removal efficiency. Moreover, the loss of TP of green tea in the proposed method was much lower than that in the hot water extraction. After decaffeination by MVIE, the removal yield of TP tea was 36.2%, and the content of TP in green tea was still higher than 170 mg g(-1). Therefore, the proposed microwave-enhanced vacuum ice water extraction was selective, more efficient for the removal of caffeine. The main phenolic compounds of green tea were also determined, and the results indicated that the contents of several catechins were almost not changed in MVIE. This study suggests that MVIE is a new and good alternative for the removal of caffeine from green tea, with a great potential for industrial application.

Ionic liquid-based ultrasonic/microwave-assisted extraction combined with UPLC-MS-MS for the determination of tannins in Galla chinensis.

Ionic liquid was used as extraction solvents and applied to the extraction of tannins from Galla chinensis in the simultaneous ultrasonic- and microwave-assisted extraction (UMAE) technique. Several parameters of UMAE were optimised, and the results were compared with of the conventional extraction techniques. Under optimal conditions, the content of tannins was 630.2 ± 12.1 mg g⁻¹. Compared with the conventional heat-reflux extraction, maceration extraction, regular ultrasound- and microwave-assisted extraction, the proposed approach exhibited higher efficiency (11.7-22.0% enhanced) and shorter extraction time (from 6 h to 1 min). The tannins were then identified by ultraperformance liquid chromatography tandem mass spectrometry. This study suggests that ionic liquid-based UMAE is an efficient, rapid, simple and green sample preparation technique.