dl-trans-3,4-Dihydroxy-1-selenolane (DHSred) heals indomethacin-mediated gastric ulcer in mice by modulating arginine metabolism

Controlling the Redox Catalytic Activity of a Cyclic Selenide Fused to 18-Crown-6 by the Conformational Transition Induced by Coordination to an Alkali Metal Ion

trans-3,4-Dihydroxyselenolane (DHS), a water-soluble cyclic selenide, exhibits selenoenzyme-like unique redox activities through reversible oxidation to the corresponding selenoxide. Previously, we demonstrated that DHS can be applied as an antioxidant against lipid peroxidation and a radioprotector by means of adequate modifications of the two hydroxy (OH) groups. Herein, we synthesized new DHS derivatives with a crown-ether ring fused to the OH groups (DHS-crown-n (n = 4 to 7), 1-4) and investigated their behaviors of complex formation with various alkali metal salts. According to the X-ray structure analysis, it was found that the two oxygen atoms of DHS change the directions from diaxial to diequatorial by complexation. The similar conformational transition was also observed in solution NMR experiments. The ¹H NMR titration in CD₃OD further confirmed that DHS-crown-6 (3) forms stable 1:1 complexes with KI, RbCl and CsCl, while it forms a 2:1 complex with KBPh₄. The results suggested that the 1:1 complex (3·MX) exchanges the metal ion with metal-free 3 through the formation of the 2:1 complex. The redox catalytic activity of 3 was evaluated using a selenoenzyme model reaction between H₂O₂ and dithiothreitol. The activity was significantly reduced in the presence of KCl due to the complex formation. Thus, the redox catalytic activity of DHS could be controlled by the conformational transition induced by coordination to an alkali metal ion.

Glycopeptides from Paecilomyces sinensis ameliorate ethanol-induced gastric ulcers via anti-inflammation and the miR-9-5p-MEK/ERK signaling pathway

The aim of this study was to investigate the immunomodulatory effect and mechanism of the glycopeptides from Paecilomyces sinensis (CPS-II) on ethanol induced ulcers in mice. In this study, histopathological evaluation (H&E staining) and the gastric ulcer score, ulcer index, total acid secretion and gastric pH value were used to determine the anti-ulcer activity. The expression levels of interleukin (IL)-6, interleukin (IL)-10 and tumor necrosis factor-α (TNF-α) were detected by ELISA. The contents of superoxide dismutase (SOD), malondialdehyde (MDA) and epidermal growth factor (PEG2) in serum were measured according to the instructions for the reagents. Western blotting was used to detect the effect of CPS-II on the MEK/ERK pathway. The results showed that CPS-II could inhibit the ulcer score and ulcer index compared with the disease control group. CPS-II could significantly increase gastric pH and decrease gastric acid secretion in mice. The ELISA analysis showed that the expression levels of IL-6 and TNF-α in the CPS-II treatment group were significantly decreased, while the expression levels of IL-10 were significantly increased in the CPS-II treatment group. In the resveratrol treatment group, the content of MDA in serum was decreased, and the level of PEG2 and the activity of SOD in serum were significantly increased, which indicated that CPS-II has immunoregulation and anti-ulcer properties. The CPS-II treatment group could reduce the expression level of miR-9-5p in gastric tissue. pEGFR had been identified as a potential target of miR-9-5p. Western blot analysis showed that CPS-II could up-regulate the relative protein expression of pEGFR/EGFR, pRaf/Raf, pMEK/MEK, pERK/ERK, and ZO-1. The results showed that CPS-II could reduce oxidative stress and inflammatory response by regulating the miR-9-5p-MEK/ERK signaling pathway, thus protecting the gastric mucosa and improving stress gastric ulcers.

Anti-ulcer effect of Gallarhois extract with anti-oxidant activity in an ICR model of ethanol/hydrochloride acid-induced gastric injury

Gallarhois (GR) is a traditional oriental herbal medicine with various pharmacological effects; however, its effect on gastric ulcer has not been previously explored. We firstly investigated the component and antioxidant activity of GR extract (EtGR) by HPLC analysis and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results showed that EtGR consisted of gallotannin (68.7%), gallic acid (27.2%) and methyl gallate (4.1%) and that it had a high antioxidant value (IC50 value; 1.93 μg/mL). To evaluate the possible anti-gastric ulcer potential of EtGR, we investigated the effects of EtGR in the model of ethanol/hydrochloric acid (EtOH/HCl)-induced gastric ulcer. Gross and histological gastric lesions, biochemical and gene expression parameters were taken into consideration. The results showed that EtOH/HCl treatment produced mucosal injuries with morphological and histological damage, whereas EtGR co-treatment reduced the gastric injuries. EtGR treatment also decreased the contents of malonaldehyde (MDA) activity relative to the vehicle group. Moreover, EtGR decreased the levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and cyclo-oxygenase-2 (COX-2) expression. Finally, EtGR did not induce any specific toxicity in the livers or kidneys of the EtOH/HCl-induced gastric ulcer model. These results suggest that EtGR had stronger antioxidant activity and could be a new useful natural drug for gastroprotection against gastric ulcer. Moreover, these findings provide a scientific basis for the development of drugs from traditional oriental herbal medicines.

Mitigation of stress from gastric mucosal injuries by mulberry extract may occur via nitric oxide synthase signaling in mice

Acute gastric mucosal injuries are serious clinical problems worldwide and are principally found with different types of stresses in animals. A constant challenge is to find original plant products that can combat stress. In the present study, we examined the effects of big-leaf mulberry extracts on stomach injury, and the activity of nitric oxide synthases (NOS) and total antioxidant activity (TAO) in the gastric mucosae of mice during water immersion and restraint stress (WIRS). Our data showed that WIRS-exposed mice produced several injuries and showed an enhanced iNOS, reduced eNOS activity, and decreased TAO activity in the stomach, whereas pretreatment with big-leaf mulberry extracts increased TAO activitiy. The data from our immunohistochemical study indicated that both iNOS and eNOS were expressed in parietal cells and blood vessels, while nNOS was only weakly expressed in parietal cells. In conclusion, our findings suggested that big-leaf mulberry mitigated WIRS-induced stomach injuries, and NOS signaling may play important roles in the mouse stomach during the recovery process.

Protective effects of trigonelline against indomethacin-induced gastric ulcer in rats and potential underlying mechanisms

The gastroprotective activity of trigonelline against indomethacin-induced ulcer and the role of anti-oxidant, anti-inflammatory and anti-apoptotic mechanisms have been explored.