Protective effect of Amauroderma rugosum ethanol extract and its primary bioactive compound, ergosterol, against acute gastric ulcers based on LXR-mediated gastric mucus secretions.

BACKGROUND: Amauroderma rugosum (Blume & T. Nees) Torrend (Ganodermataceae) is an edible mushroom with a wide range of medicinal values. Our previous publication demonstrated the therapeutic effects of the water extract of A. rugosum (WEA) against gastric ulcers. However, the protective effects of the ethanol extract of A. rugosum (EEA) on gastric mucosa and its major active constituents have not yet been elucidated. PURPOSE: This study aims to evaluate the gastroprotective effects and underlying mechanisms of EEA and its fat-soluble constituent, ergosterol, in acute gastric ulcers. STUDY DESIGN AND METHOD: SD rats were pre-treated with EEA (50, 100, and 200 mg/kg) or ergosterol (5, 10, and 20 mg/kg), and acute gastric ulcer models were constructed using ethanol, gastric mucus secretion inhibitor (indomethacin) or pyloric-ligation. The gastric ulcer area, histological structure alterations (H&E staining), and mucus secretion (AB-PAS staining) were recorded. Additionally, Q-PCR, western blotting, immunohistochemistry, ELISA, molecular docking, molecular dynamics simulations, MM-GBSA analysis, and surface plasmon resonance assay (SPR) were used to investigate the underlying mechanisms of the gastroprotective effect. RESULT: Compared with WEA, which primarily exerts its anti-ulcer effects by inhibiting inflammation, EEA containing fat-soluble molecules showed more potent gastroprotective effect through the promotion of gastric mucus secretion, as the anti-ulcer activity was partly blocked by indomethacin. Meanwhile, EEA exhibited anti-inflammatory effects by suppressing the production of IL-6, IL-1ß, TNF-α, and NO, thereby inhibiting the MAPK pathway. Significantly, ergosterol (20 mg/kg), the bioactive water-insoluble compound in EEA, exhibited a gastroprotective effect comparable to that of lansoprazole (30 mg/kg). The promotion of gastric mucus secretion contributed to the effects of ergosterol, as indomethacin can completely block it. The upregulations of COX1-PGE2 and C-fos, an activator protein 1 (AP-1) transcription factor, were observed after the ergosterol treatment. Ergosterol acted as an LXRß agonist via van der Waals binding and stabilizing the LXRß protein without compromising its flexibility, thereby inducing the upregulation of AP-1 and COX-1. CONCLUSION: EEA and its primary bioactive compound, ergosterol, exert anti-ulcer effects by promoting gastric mucus secretion through the LXRß/C-fos/COX-1/PGE2 pathway.

Gastroprotective effects of water extract of domesticated Amauroderma rugosum against several gastric ulcer models in rats.

CONTEXT: Amauroderma rugosum (Blume & T. Nees) Torrend (Ganodermataceae) is an edible mushroom with medicinal properties. However, the effects of A. rugosum on gastric ulcer remain unclear. OBJECTIVE: To investigate the gastroprotective efficacy of water extract of A. rugosum (WEA) on gastric ulcer. MATERIALS AND METHODS: Sprague-Dawley rats were randomly grouped as control, model, lansoprazole and 200, 100 and 50 mg/kg of WEA. After pre-treatment for seven days, ethanol- and indomethacin-induced gastric ulcer models were established. The gastric ulcer and histopathology were investigated. Enzyme-linked immunosorbent assay (ELISA), quantitative polymerase chain reaction (Q-PCR) and Western blot assays were conducted to explore the potential anti-inflammatory effect and mechanism of WEA. Additionally, the pyloric ligation model was used to explore the influence of WEA on gastric acid and mucus. RESULTS: Pre-treatment with WEA (200, 100 and 50 mg/kg) effectively reduced ulcerous area in both ethanol-induced (71%, 88% and 71%) and indomethacin-induced (77%, 65% and 86%) gastric ulcer model. The gastric levels of tumour necrosis factor-alpha (TNF-α) (34% and 50 mg/kg), interleukin-6 (IL-6) (32% and 100 mg/kg) and interleukin-1ß (IL-1ß) (36%, 45% and 41%) were reduced significantly (p < 0.05) by WEA. Serum nitric oxide was decreased significantly (p < 0.05) at 200 and 50 mg/kg and PGE2 concentration was increased remarkably (p < 0.05) at 100 mg/kg. Gene expression of inflammasome Nlrp3, and the nuclear translocation of nuclear factor-κB (NF-κB) P65 were significantly decreased by WEA pre-treatment. However, the pH of gastric acid and secretion of mucus did not show any significant change. CONCLUSIONS: The gastroprotective effect of WEA on gastric damage is attributed to anti-inflammation through the inhibition on NF-κB P65 nuclear migration and Nlrp3 gene expression.

A practical random mutagenesis system for Ralstonia solanacearum strains causing bacterial wilt of Pogostemon cablin using Tn5 transposon.

A practical random mutagenesis system of Ralstonia solanacearum by electroporation with Tn5 transposon was established, which may be utilized to provide genetic approach to study virulence genes of R. solanacearum strains and create nonpathogenic mutants for biological control of bacterial wilt in Pogostemon cablin. R. solanacearum strain PRS-84 used in this study was isolated from P. cablin plants infected with bacterial wilt. The bacterial suspension of R. solanacearum strain PRS-84 was mixed with Tn5 transposome complex and the mixture was transformed by electroporation. The electroporated cells were then spread on the 2, 3, 5-triphenyltetrazolium chloride agar plates containing kanamycin to select the kanamycin-resistant colonies. Several factors which determined the bacterial transformation efficiency were optimized. The transformation process was shown to be optimal at the electric field strength of 12.5 kV cm-1. Bacterial cells harvested at mid-exponential phase gave the highest transformation efficiency. 10 µg mL-1 kanamycin was found to be the optimal concentration for transformant selection. Tn5 insertion mutants of R. solanacearum strain PRS-84 were identified by PCR amplification and Southern blot analysis. Mutants subcultured for 100 passages were also detected by PCR amplification and Southern blot analysis. Furthermore, pathogenicity screening test of mutants was performed by inoculating in vitro regenerated patchouli plants. Results revealed that mutants with a single Tn5 insertion in their genomes were obtained from R. solanacearum strain PRS-84, and the Tn5 insertion could be stably inherited in the mutants. Then, mutants with reduced pathogenicity were selected.

[Enzyme-catalyzed synthesis of ASGPR ligand-targeted modifier in non-aqueous medium].

The asialoglycoprotein receptor (ASGPR) was used to mediate drug carrier for hepatic targeted drug delivery, this article showed the enzyme-catalyzed esterification of galactose and vinyl stearate and a kind of ASGPR ligand-targeted which was used to insert the surface of liposome has been synthesized. The structure of product has been confirmed by TLC, ESI-MS and 1H NMR. The factors of types and quantity of enzyme, organic solvents, molar ratio of substrate, temperature and time of reaction have been studied. Results showed when using acetone as reaction medium, the quantity of Novozym 435 immobilized lipase was 30 mg mL(-1), molar ratio of galactose to vinyl stearate was 1:5, and reacted at 60 degrees C for 12 h, the transformation of vinyl stearate reached more than 70%. This study provides a novel and efficient route to the synthesis of ligand-targeted modifier.