Potential mechanisms underlying the ameliorative effect of Lactobacillus paracasei FZU103 on the lipid metabolism in hyperlipidemic mice fed a high-fat diet.

Lactobacillus paracasei FZU103, a probiotic previously isolated from the traditional brewing process of Hongqu rice wine, may have the beneficial effect of improving the disorder of lipid metabolism. This study aimed to determine the beneficial effects of L. paracasei FZU103 on improving hepatic lipid accumulation associated with hyperlipidemia. Results indicated that L. paracasei FZU103 intervention significantly inhibited the abnormal growth of body weight and epididymal white adipose tissue (eWAT), prevented the hypertrophy of epididymal adipocytes, ameliorated the biochemical parameters of serum and liver related to lipid metabolism in HFD-fed mice. Histological analysis also showed that the excessive accumulation oflipid dropletsin the livers induced by HFD-feeding was greatly alleviated by L. paracasei FZU103 intervention. In addition, L. paracasei FZU103 also promoted the excretion of bile acids (BAs) through feces. Metagenomic analysis revealed that oral supplementation with L. paracasei FZU103 significantly increased the relative abundance of Ruminococcus, Alistipes, Pseudoflavonifractor and Helicobacter, but decreased the levels of Blautia, Staphylococcos and Tannerella in HFD-fed mice. The relationships between lipid metabolic parameters and intestinal microbial phylotypes were also revealed by correlation heatmap and network. Furthermore, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS)-based liver metabolomics demonstrated that L. paracasei FZU103 had a significant regulatory effect on the metabolic pathways of glycerophospholipid metabolism, fatty acid degradation, fatty acid elongation, unsaturated fatty acids biosynthesis, riboflavin metabolism, glycerolipid metabolism, primary bile acid biosynthesis, arachidonic acid metabolism, etc. Additionally, L. paracasei FZU103 intervention regulated expression of hepatic genes involved in lipid metabolism and bile acid homeostasis, and promoted fecal excretion of intestinal BAs. These findings present new evidence supporting that L. paracasei FZU103 has the potential to improve lipid metabolism, and could be used as a potential functional food for the prevention of hyperlipidemia.

Biological evaluation and molecular docking of baicalin and scutellarin as Helicobacter pylori urease inhibitors.

ETHNOPHARMACOLOGICAL RELEVANCE: Baicalin and scutellarin are the principal bioactive components of Scutellaria baicalensis Georgi which has extensively been incorporated into heat-clearing and detoxification formulas for the treatment of Helicobacter pylori-related gastrointestinal disorders in traditional Chinese medicine. However, the mechanism of action remained to be defined. AIM OF THE STUDY: To explore the inhibitory effect, kinetics and mechanism of Helicobacter pylori urease (the vital pathogenetic factor for Helicobacter pylori infection) inhibition by baicalin and scutellarin, for their therapeutic potential. MATERIALS AND METHODS: The ammonia formations, indicator of urease activity, were examined using modified spectrophotometric Berthelot (phenol-hypochlorite) method. The inhibitory effect of baicalin and scutellarin was characterized with IC50 values, compared to acetohydroxamic acid (AHA), a well known Helicobacter pylori urease inhibitor. Lineweaver-Burk and Dixon plots for the Helicobacter pylori urease inhibition of baicalin and scutellarin was constructed from the kinetic data. SH-blocking reagents and competitive active site Ni(2+) binding inhibitors were employed for mechanism study. Molecular docking technique was used to provide some information on binding conformations as well as confirm the inhibition mode. Moreover, cytotoxicity experiment using Gastric Epithelial Cells (GES-1) was evaluated. RESULTS: Baicalin and scutellarin effectively suppressed Helicobacter pylori urease in dose-dependent and time-independent manner with IC50 of 0.82±0.07 mM and 0.47±0.04 mM, respectively, compared to AHA (IC50=0.14±0.05 mM). Structure-activity relationship disclosed 4'-hydroxyl gave flavones an advantage to binding with Helicobacter pylori urease. Kinetic analysis revealed that the types of inhibition were non-competitive and reversible with inhibition constant Ki of 0.14±0.01 mM and 0.18±0.02 mM for baicalin and scutellarin, respectively. The mechanism of urease inhibition was considered to be blockage of the SH groups of Helicobacter pylori urease, since thiol reagents (L,D-dithiothreitol, L-cysteine and glutathione) abolished the inhibitory action and competitive active site Ni(2+) binding inhibitors (boric acid and sodium fluoride) carried invalid effect. Molecular docking study further supported the structure-activity analysis and indicated that baicalin and scutellarin interacted with the key residues Cys321 located on the mobile flap through S-H·π interaction, but did not interact with active site Ni(2+). Moreover, Baicalin (at 0.59-1.05 mM concentrations) and scutellarin (at 0.23-0.71 mM concentrations) did not exhibit significant cytotoxicity to GES-1. CONCLUSIONS: Baicalin and scutellarin were non-competitive inhibitors targeting sulfhydryl groups especially Cys321 around the active site of Helicobacter pylori urease, representing potential to be good candidate for future research as urease inhibitor for treatment of Helicobacter pylori infection. Furthermore, our work gave additional scientific support to the use of Scutellaria baicalensis in traditional Chinese medicine (TCM) to treat gastrointestinal disorders.

Selective antibacterial activity of patchouli alcohol against Helicobacter pylori based on inhibition of urease.

The aim of this study is to evaluate the antibacterial activity and urease inhibitory effects of patchouli alcohol (PA), the bioactive ingredient isolated from Pogostemonis Herba, which has been widely used for the treatment of gastrointestinal disorders. The activities of PA against selected bacteria and fungi were determined by agar dilution method. It was demonstrated that PA exhibited selective antibacterial activity against Helicobacter pylori, without influencing the major normal gastrointestinal bacteria. Noticeably, the antibacterial activity of PA was superior to that of amoxicillin, with minimal inhibition concentration value of 78 µg/mL. On the other hand, PA inhibited ureases from H.pylori and jack bean in concentration-dependent fashion with IC50 values of 2.67 ± 0.79 mM and 2.99 ± 0.41 mM, respectively. Lineweaver-Burk plots indicated that the type of inhibition was non-competitive against H.pylori urease whereas uncompetitive against jack bean urease. Reactivation of PA-inactivated urease assay showed DL-dithiothreitol, the thiol reagent, synergistically inactivated urease with PA instead of enzymatic activity recovery. In conclusion, the selective H.pylori antibacterial activity along with urease inhibitory potential of PA could make it a possible drug candidate for the treatment of H.pylori infection.

Gastroprotective effect and mechanism of patchouli alcohol against ethanol, indomethacin and stress-induced ulcer in rats.

Pogostemonis Herba is an important Chinese medicine widely used in the treatment of gastrointestinal dysfunction. Patchouli alcohol (PA), a tricyclic sesquiterpene, is the major active constituent of Pogostemonis Herba. This study aimed to investigate the possible anti-ulcerogenic potential of PA and the underlying mechanism against ethanol, indomethacin and water immersion restraint-induced gastric ulcers in rats. Gross and histological gastric lesions, biochemical and immunological parameters were taken into consideration. The gastric mucus content and the antisecretory activity were analyzed through pylorus ligature model in rats. Results indicated that oral administration with PA significantly reduced the ulcer areas induced by ethanol, indomethacin and water immersion restraint. PA pretreatment significantly promoted gastric prostaglandin E2 (PGE2) and non-protein sulfhydryl group (NP-SH) levels, upregulated the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) mRNA expression, and considerably boosted the gastric blood flow (GBF) and gastric mucus production in comparison with vehicle. In addition, PA modulated the levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α). The levels of glutathione (GSH), catalase (CAT) and malonaldehyde (MDA) were also restored by PA. However, the gastric secretion parameters (pH, volume of gastric juice and pepsin) did not show any significant alteration. These findings suggest that PA exhibited significant gastroprotective effects against gastric ulceration. The underlying mechanisms might involve the stimulation of COX-mediated PGE2, improvement of antioxidant and anti-inflammatory status, preservation of GBF and NP-SH, as well as boost of gastric mucus production.

[Gene cloning and bioinformatics analysis of SABATH methyltransferase in Lonicera japonica var. chinensis].

OBJECTIVE: To clone SABATH methyltransferase (rLjSABATHMT) gene in Lonicera japonica var. chinensis, and compare the gene expression and intron sequence of SABATH methyltransferase orthologous in L. japonica with L. japonica var. chinensis. It provide a basis for gene regulate the formation of L. japonica floral scents. METHOD: The cDNA and genome sequences of LjSABATHMT from L. japonica var. chinensis were cloned according to the gene fragments in cDNA library. The LjSABATHMT protein was characterized by bioinformatics analysis. SABATH family phylogenetic tree were built by MEGA 5.0. The transcripted level of SABATHMT orthologous were analyzed in different organs and different flower periods of L. japonica and L. japonica var. chinensis using RT-PCR analysis. Intron sequences of SABATHMT orthologous were also analyzied. RESULT: The cDNA of LjSABATHMT was 1 251 bp, had a complete coding frame with 365 amino acids. The protein had the conservative SABATHMT domain, and phylogenetic tree showed that it may be a salicylic acid/benzoic acid methyltransferase. Higher expression of SABATH methyltransferase orthologous was found in flower. The intron sequence of L. japonica and L. japonica var. chinensis had rich polymorphism, and two SNP are unique genotype of L. japonica var. chinensis. The motif elements in two orthologous genes were significant differences. CONCLUSION: The intron difference of SABATH methyltransferase orthologous could be inducing to difference of gene expression between L. japonica and L. japonica var. chinensis. These results will provide important base on regulating active compounds of L. japonica.

Inactivation of jack bean urease by scutellarin: elucidation of inhibitory efficacy, kinetics and mechanism.

In the present study, the inactivation effect of scutellarin (SL) on jack bean urease was investigated to elucidate the inhibitory potency, kinetics and mechanism of inhibition. It was revealed that SL acted as a concentration- and time-dependent inactivator of urease characteristic of slow-binding inhibition with an IC50 of 1.35±0.15 mM. The rapid formation of the initial SL-urease complex with an inhibition constant of Ki=5.37×10(-2) mM was followed by a slow isomerization into the final complex with the overall inhibition constant of Ki*=3.49×10(-3) mM. High effectiveness of thiol protectors, such as L-cysteine (L-cys), 2-mercaptoethanol (2-ME) and dithiothreitol (DTT) significantly slowed down the rate of inactivation, indicating the strategic role of the active site sulfhydryl group in the blocking process. While the insignificant protection by boric acid and fluoride from the inactivation further confirmed that the active site cysteine should be obligatory for urease inhibition, which was also rationalized by the molecular docking study. The inhibition of SL on urease proved to be reversible since SL-blocked urease could be reactivated by DTT application and multidilution. The results obtained indicated that urease inactivation resulted from the reaction between SL and the sulfhydryl group.

Apigenin inhibits proliferation and induces apoptosis in human multiple myeloma cells through targeting the trinity of CK2, Cdc37 and Hsp90.

BACKGROUND: Multiple myeloma (MM) is a B-cell malignancy that is largely incurable and is characterized by the accumulation of malignant plasma cells in the bone marrow. Apigenin, a common flavonoid, has been reported to suppress proliferation in a wide variety of solid tumors and hematological cancers; however its mechanism is not well understood and its effect on MM cells has not been determined. RESULTS: In this study, we investigated the effects of apigenin on MM cell lines and on primary MM cells. Cell viability assays demonstrated that apigenin exhibited cytotoxicity against both MM cell lines and primary MM cells but not against normal peripheral blood mononuclear cells. Together, kinase assays, immunoprecipitation and western blot analysis showed that apigenin inhibited CK2 kinase activity, decreased phosphorylation of Cdc37, disassociated the Hsp90/Cdc37/client complex and induced the degradation of multiple kinase clients, including RIP1, Src, Raf-1, Cdk4 and AKT. By depleting these kinases, apigenin suppressed both constitutive and inducible activation of STAT3, ERK, AKT and NF-κB. The treatment also downregulated the expression of the antiapoptotic proteins Mcl-1, Bcl-2, Bcl-xL, XIAP and Survivin, which ultimately induced apoptosis in MM cells. In addition, apigenin had a greater effects in depleting Hsp90 clients when used in combination with the Hsp90 inhibitor geldanamycin and the histone deacetylase inhibitor vorinostat. CONCLUSIONS: Our results suggest that the primary mechanisms by which apigenin kill MM cells is by targeting the trinity of CK2-Cdc37-Hsp90, and this observation reveals the therapeutic potential of apigenin in treating multiple myeloma.