Oxidative stress has been implicated in the pathogenesis of many kinds of neurodegenerative disorders, particularly Parkinson’s disease. Quercetin is a bioflavonoid found ubiquitously in fruits and vegetables, and has antioxidative activity. However, the underlying mechanism of the antioxidative effect of quercetin in neurodegenerative diseases has not been well explored. Here, we investigated the antioxidative effect and underlying molecular mechanisms of quercetin on PC-12 cells. We found that PC-12 cells pretreated with quercetin exhibited an increased cell viability and reduced lactate dehydrogenase (LDH) release when exposed to hydrogen peroxide (H₂O₂). The significantly-alleviated intracellular reactive oxygen species (ROS), malondialdehyde (MDA), and lipoperoxidation of the cell membrane of PC-12 cells induced by H₂O₂ were observed in the quercetin pretreated group. Furthermore, quercetin pretreatment markedly reduced the apoptosis of PC-12 cells and hippocampal neurons. The inductions of antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in PC-12 cells exposed to H₂O₂ were significantly reduced by preatment with quercetin. In addition, quercetin pretreatment significantly increased Bcl-2 expression, and reduced Bax, cleaved caspase-3 and p53 expressions. In conclusion, this study demonstrated that quercetin exhibited a protective effect against oxidative stress-induced apoptosis in PC-12 cells. Our findings suggested that quercetin may be developed as a novel therapeutic agent for neurodegenerative diseases induced by oxidative stress.

The effects of ginger on gastrointestinal disorders such as ulcerative colitis have been widely investigated using experimental models; however, the mechanisms underlying its therapeutic actions are still unknown. In this study, we investigated the correlation between the therapeutic effects of ginger and the regulation of the gut microbiota. We used dextran sulfate sodium (DSS) to induce colitis and found that ginger alleviated colitis-associated pathological changes and decreased the mRNA expression levels of interleukin-6 and inducible nitric oxide synthase in mice. 16s rRNA sequencing analysis of the feces samples showed that mice with colitis had an intestinal flora imbalance with lower species diversity and richness. At the phylum level, a higher abundance of pathogenic bacteria, Proteobacteria and firmicutes, were observed; at the genus level, most samples in the model group showed an increase in Lachnospiraceae_NK4A136_group. The overall analysis illustrated an increase in the relative abundance of Lactobacillus_murinus, Lachnospiraceae_bacterium_615, and Ruminiclostridium_sp._KB18. These increased pathogenic bacteria in model mice were decreased when treated with ginger. DSS-treated mice showed a lower abundance of Muribaculaceae, and ginger corrected this disorder. The bacterial community structure of the ginger group analyzed with Alpha and Beta indices was similar to that of the control group. The results also illustrated that altered intestinal microbiomes affected physiological functions and adjusted key metabolic pathways in mice. In conclusion, this research presented that ginger reduced DSS-induced colitis severity and positively regulated the intestinal microbiome. Based on the series of data in this study, we hypothesize that ginger can improve diseases by restoring the diversity and functions of the gut microbiota.

Apolipoprotein E4 (ApoE4) is the main genetic risk factor for Alzheimer’s disease (AD), but the exact way in which it causes AD remains unclear. Curcumin is considered to have good therapeutic potential for AD, but its mechanism has not been clarified. This study aims to observe the effect of curcumin on ApoE4 transgenic mice and explore its possible molecular mechanism. Eight-month-old ApoE4 transgenic mice were intraperitoneally injected with curcumin for 3 weeks, and the Morris water maze test was used to evaluate the cognitive ability of the mice. Immunofluorescence staining, immunohistochemistry, western blotting, and enzyme-linked immunosorbent assay (ELISA) were used to examine the brain tissues of the mice. Curcumin reduced the high expression of ApoE4 and the excessive release of inflammatory factors in ApoE4 mice. In particular, the expression of marker proteins of endoplasmic reticulum (ER) stress was significantly increased in ApoE4 mice, while curcumin significantly reduced the increase in the expression of these proteins. Collectively, curcumin alleviates neuroinflammation in the brains of ApoE4 mice by inhibiting ER stress, thus improving the learning and cognitive ability of transgenic mice.