Dendrobium huoshanense stem polysaccharide ameliorates alcohol-induced gastric ulcer in rats through Nrf2-mediated strengthening of gastric mucosal barrier

This study aimed to explore whether Dendrobium huoshanense stem polysaccharide (cDHPS) ameliorates alcohol-induced gastric ulcer (GU) through the strengthening effect of the gastric mucosal barrier in rats and its potential mechanism. In normal rats, the pretreatment of cDHPS effectively strengthened gastric mucosal barrier by increasing mucus secretion and tight junction protein expression. In GU rats, cDHPS supplementation effectively alleviated alcohol-induced gastric mucosal injury and nuclear factor κB (NF-κB)-driven inflammation by strengthening gastric mucosal barrier. Moreover, cDHPS significantly activated nuclear factor E2-related factor 2 (Nrf2) signaling and promoted antioxidant enzymes activities in both normal and GU rats. These results suggested that the pretreatment of cDHPS could strengthen gastric mucosal barrier to inhibit oxidative stress and NF-κB-driven inflammation induced gastric mucosal injury, which was likely related to the activation of Nrf2 signaling.

Dendrobine inhibits dopaminergic neuron apoptosis via MANF-mediated ER stress suppression in MPTP/MPP+-induced Parkinson's disease models

BACKGROUND

Parkinson's disease (PD) is an age-related neurodegenerative disorder without effective treatments. Mesencephalic astrocyte-derived neurotrophic factor (MANF) has been suggested to be capable of protecting against PD by inhibiting endoplasmic reticulum (ER) stress-mediated neuronal apoptosis.

PURPOSE

This study was aimed to evaluate the antiparkinsonian effect of dendrobine and reveal its underlying mechanisms from the perspective of MANF-mediated ER stress suppression.

METHODS

Behavioral assessments of PD mice as well as LDH/CCK-8 assay in SH-SY5Y cells and primary midbrain neurons were carried out to detect the antiparkinsonian effect of dendrobine. Immunofluorescence, western blot, flow cytometry and shRNA-mediated MANF knockdown were used to determine the apoptosis of dopaminergic neurons and the expressions of ER stress-related proteins for investigating the underlying mechanism of dendrobine.

RESULTS

Dendrobine significantly ameliorated the motor performance of PD mice and attenuated the injuries of dopaminergic neurons. Dendrobine could also relieve neuronal apoptosis, up-regulate MANF expression and inhibit ER stress, which were largely abolished by shRNA-mediated MANF knockdown in PD model.

CONCLUSION

Dendrobine might protect against PD by inhibiting dopaminergic neuron apoptosis, which was achieved by facilitating MANF-mediated ER stress suppression. Our study suggested that dendrobine could act as a MANF up-regulator to protect against PD, and provided a potential candidate for exploring etiological agents of PD.

Anti-gastric cancer activity of cultivated Dendrobium huoshanense stem polysaccharide in tumor-bearing mice: Effects of molecular weight and O-acetyl group

The present study aimed at assuring whether homogeneous cultivated Dendrobium huoshanense stem polysaccharide (cDHPS) could inhibit gastric cancer in vivo, and whether its anti-gastric cancer activity could be affected by its molecular weight and O-acetyl group. Three different fractions (cDHPS-I, cDHPS-II and cDHPS-III) with decreased molecular weights and one fraction (cDHPS-IV) without O-acetyl group were prepared from cDHPS. Their structures were identified systematically. The backbone of cDHPS-I-III was the same as that of cDHPS, while their relative molecular weights displayed a decreasing order as follows: cDHPS > cDHPS-I > cDHPS-II > cDHPS-III. The backbone of cDHPS-IV was similar to those of cDHPS and cDHPS-I-III, but with the absence of O-acetyl groups. Animal experiments exhibited that cDHPS and cDHPS-I-IV could significantly inhibit tumor growth, induce tumor cell apoptosis, suppress tumor angiogenesis and enhance T cell immune response of murine forestomach carcinoma (MFC) tumor-bearing mice. Moreover, all the above effects of cDHPS and cDHPS-I-IV on MFC tumor-bearing mice exhibited a decreasing order as follows: cDHPS > cDHPS-I > cDHPS-II > cDHPS-III > cDHPS-IV. The results suggest that cDHPS could inhibit gastric cancer in vivo, and its anti-gastric cancer activity was closely linked with its molecular weight and O-acetyl group.

Dendrobium huoshanense stem polysaccharide ameliorates rheumatoid arthritis in mice via inhibition of inflammatory signaling pathways

The present study explored the beneficial effect of Dendrobium huoshanense stem polysaccharide (cDHPS) after oral administration on rheumatoid arthritis (RA) using type Ⅱ collagen-induced arthritis (CIA) mouse model. It was found that cDHPS effectively alleviated joint swelling, synovial hyperplasia, pannus formation, cartilage erosion and bone destruction in CIA mice. Concurrently, cDHPS remodeled the balance of Th17 and regulatory T cells, reduced the secretion of pro-inflammatory mediators related to fibroblast-like synoviocyte activation, angiogenesis, articular cartilage degradation and osteoclast differentiation, inhibited HIF-1α expression and promoted anti-inflammatory mediator release in the joint tissues and serum of CIA mice. Western blot of joint tissues showed that cDHPS significantly inhibited the phosphorylation of IκB, p65, JNK, p38, ERK1/2, AKT, PI3K, JAK1 and STAT3 in CIA mice. These results suggest that cDHPS possesses the potential of ameliorating RA and its anti-RA effect may be attributed to the inhibition of inflammatory signaling pathways.