3-B-RUT, a derivative of RUT, protected against alcohol-induced liver injury by attenuating inflammation and oxidative stress

The Role of Oxidative Stress in Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Preclinical Studies

Alcoholic Fatty Liver Disease (AFLD) is characterized by the accumulation of lipids in liver cells owing to the metabolism of ethanol. This process leads to a decrease in the NAD+/NADH ratio and the generation of reactive oxygen species. A systematic review and meta-analysis were conducted to investigate the role of oxidative stress in AFLD. A total of 201 eligible manuscripts were included, which revealed that animals with AFLD exhibited elevated expression of CYP2E1, decreased enzymatic activity of antioxidant enzymes, and reduced levels of the transcription factor Nrf2, which plays a pivotal role in the synthesis of antioxidant enzymes. Furthermore, animals with AFLD exhibited increased levels of lipid peroxidation markers and carbonylated proteins, collectively contributing to a weakened antioxidant defense and increased oxidative damage. The liver damage in AFLD was supported by significantly higher activity of alanine and aspartate aminotransferase enzymes. Moreover, animals with AFLD had increased levels of triacylglycerol in the serum and liver, likely due to reduced fatty acid metabolism caused by decreased PPAR-α expression, which is responsible for fatty acid oxidation, and increased expression of SREBP-1c, which is involved in fatty acid synthesis. With regard to inflammation, animals with AFLD exhibited elevated levels of pro-inflammatory cytokines, including TNF-a, IL-1β, and IL-6. The heightened oxidative stress, along with inflammation, led to an upregulation of cell death markers, such as caspase-3, and an increased Bax/Bcl-2 ratio. Overall, the findings of the review and meta-analysis indicate that ethanol metabolism reduces important markers of antioxidant defense while increasing inflammatory and apoptotic markers, thereby contributing to the development of AFLD.

Promising derivatives of rutaecarpine with diverse pharmacological activities

Rutaecarpine (RUT) is a natural pentacyclic indolopyridoquinazolinone alkaloid first isolated from one of the most famous traditional Chinese herbs, Evodia rutaecarpa, which is used for treating a variety of ailments, including headaches, gastrointestinal disorders, postpartum hemorrhage, amenorrhea, difficult menstruation, and other diseases. Accumulating pharmacological studies showed that RUT possesses a wide range of pharmacological effects through different mechanisms. However, its poor physicochemical properties and moderate biological activities have hampered its clinical application. In this regard, the modification of RUT aimed at seeking its derivatives with better physicochemical properties and more potency has been extensively studied. These derivatives exhibit diverse pharmacological activities, including anti-inflammatory, anti-atherogenic, anti-Alzheimer's disease, antitumor, and antifungal activities via a variety of mechanisms, such as inhibiting cyclooxygenase-2 (COX-2), acetylcholine (AChE), phosphodiesterase 4B (PDE4B), phosphodiesterase 5 (PDE5), or topoisomerases (Topos). From this perspective, this paper provides a comprehensive description of RUT derivatives by focusing on their diverse biological activities. This review aims to give an insight into the biological activities of RUT derivatives and encourage further exploration of RUT.

Antioxidant and anti-inflammatory agents in chronic liver diseases: Molecular mechanisms and therapy

Chronic liver disease (CLD) is a continuous process that causes a reduction of liver function lasting more than six months. CLD includes alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), chronic viral infection, and autoimmune hepatitis, which can lead to liver fibrosis, cirrhosis, and cancer. Liver inflammation and oxidative stress are commonly associated with the development and progression of CLD. Molecular signaling pathways such as AMP-activated protein kinase (AMPK), C-Jun N-terminal kinase, and peroxisome proliferator-activated receptors (PPARs) are implicated in the pathogenesis of CLD. Therefore, antioxidant and anti-inflammatory agents from natural products are new potent therapies for ALD, NAFLD, and hepatocellular carcinoma (HCC). In this review, we summarize some powerful products that can be potential applied in all the stages of CLD, from ALD/NAFLD to HCC. The selected agents such as β-sitosterol, curcumin, genistein, and silymarin can regulate the activation of several important molecules, including AMPK, Farnesoid X receptor, nuclear factor erythroid 2-related factor-2, PPARs, phosphatidylinositol-3-kinase, and lysyl oxidase-like proteins. In addition, clinical trials are undergoing to evaluate their efficacy and safety.

Theragra chalcogramma Hydrolysates, Rich of Fragment Gly-Leu-Pro-Ser-Tyr-Thr, Ameliorate Alcohol-Induced Cognitive Impairment via Attenuating Neuroinflammation and Enhancing Neuronal Plasticity in Sprague-Dawley Rats

Chronic alcohol abuse induces the cognitive deficits and is associated with low-grade inflammation and neurodegeneration. Currently, by virtue of the immunomodulatory and neuroprotective properties, nutrients represent a promising strategy to attenuate cognitive impairments. We previously prepared the hydrolysates from Theragra chalcogramma skin (TCH), and this study aims to evaluate the neuroprotection of TCH on alcohol-induced cognitive impairment (AICI) and to elucidate the associated mechanism. Behavioral results showed that TCH effectively ameliorated AICI and this amelioration was highly associated with the decrease of IL-1β and the increase of BDNF, CREB, and PSD95 in AICI rats (P < 0.05). Furthermore, TCH restored the histopathological impairment in hippocampus by reactivating extracellular signal-regulated kinase and suppressing Caspase-3 apoptosis signal pathways and modulating the abnormality of neurotransmitters acetylcholine and γ-aminobutyric acid(P < 0.05 or 0.01). Therefore, TCH exhibits potent attenuation of neuroinflammation and represents a potential ingredient for prevention of AICI.

Rhoifolin Alleviates Alcoholic Liver Disease In Vivo and In Vitro via Inhibition of the TLR4/NF-κB Signaling Pathway

Background: Alcoholic liver disease (ALD) is a common chronic liver disorder worldwide, which is detrimental to human health. A preliminary study showed that the total flavonoids within Citrus grandis “Tomentosa” exerted a remarkable effect on the treatment of experimental ALD. However, the active substances of Citrus grandis “Tomentosa” were not elucidated. Rhoifolin (ROF) is a flavonoid component present in high levels. Therefore, this research aimed to evaluate the hepatoprotective effects of ROF and its possible mechanisms.

Methods: Molecular docking was performed to analyze the binding energy of ROF to the main target proteins related to ALD. Subsequently, mice were fed ethanol (ETH) for 49 days to establish the chronic alcoholic liver injury models. The liver pathological injury, serum aminotransferase levels, and oxidative stress levels in the liver tissue were measured. Human normal hepatocytes (LO2 cells) were incubated with ETH to construct the alcoholic liver cell model. The inflammatory markers and apoptosis factors were evaluated using real-time PCR and flow cytometry. Finally, the effects of ROF on the CYP2E1 and NF-κB signaling pathways were tested in vitro and in vivo.

Results: Molecular docking results demonstrated that ROF was able to successfully dock with the target proteins associated with ALD. In animal studies, ROF attenuated ETH-induced liver damage in mice by decreasing the serum concentrations of AST and ALT, reducing the expression of inflammatory cytokines, and maintaining antioxidant balance in the liver tissue. The in vitro experiments demonstrated that ROF suppressed ETH-induced apoptosis in LO2 cells by promoting Bcl-2 mRNA and inhibiting Bax mRNA and caspase 3 protein expression. ROF decreased the level of LDH, ALT, AST, ROS, and MDA in the supernatant; induced the activity of GSH and SOD; and inhibited TNF-α, IL-6, and IL-1β expression levels. Mechanistically, ROF could significantly downregulate the expression levels of CYP2E1, TLR4, and NF-κB phosphorylation.

Conclusion: This study indicates that ROF is the active component within the total flavonoids, which may alleviate ETH-induced liver injury by inhibiting NF-κB phosphorylation. Therefore, ROF may serve as a promising compound for treating ALD.

DNMT3a-mediated methylation of PSTPIP2 enhances inflammation in alcohol-induced liver injury via regulating STAT1 and NF-κB pathway

Alcohol-induced liver injury (ALI) is associated with inflammatory responses regulated by macrophages. Activation of macrophages plays a crucial role in ALI while DNA methylation-regulated gene silencing is associated with inflammation processes in macrophages. Proline-Serine-Threonine Phosphatase Interacting Protein 2 (PSTPIP2), which belongs to the Fes/CIP4 homology-Bin/Amphiphysin/Rvs domain family of proteins and plays a role in macrophages. Previous studies have shown that Pstpip2 can be methylated. Herein, its expression was found to be significantly downregulated in primary liver macrophages isolated from EtOH-fed mice and EtOH-induced RAW264.7 cells. Overexpression of PSTPIP2 using liver-specific recombinant AAV serotype 9 (rAAV9)-PSTPIP2 in EtOH-fed mice dramatically alleviated liver injury and inflammatory responses. In addition, silencing of PSTPIP2 aggravated the alcohol-induced inflammatory response in vitro. Mechanistically, PSTPIP2 might affect macrophage-induced inflammatory responses by regulating the STAT1 and NF-κB signaling pathways. The downregulation of PSTPIP2 in ALI may be associated with DNA methylation. Methylation-specific PCR and western blotting analyses showed that EtOH induced abnormal DNA methylation patterns and increased the protein expression levels of DNMT1, DNMT3a, and DNMT3b. The chromatin immunoprecipitation assay showed that DNMT3a could directly bind to the Pstpip2 promoter and act as a principal regulator of PSTPIP2 expression. Moreover, silencing of DNMT3a significantly restored the EtOH-induced low expression of PSTPIP2 and inhibited EtOH-induced inflammation. Overall, these findings provide a detailed understanding of the possible functions and mechanisms of PSTPIP2 in ALI, thus providing new substantive research to elucidate the pathogenesis of ALI and investigate potential targeted treatment strategies.

Walnut protein hydrolysates ameliorate alcohol-induced cognitive impairment (AICI) by alleviating oxidative stress and inflammation in the brain and improving hippocampal synaptic plasticity in Sprague–Dawley rats

Walnut protein hydrolysate (WPH) ameliorates Alcohol-induced cognitive impairment (AICI) via alleviating oxidative stress and inflammation in brain tissue and improving the hippocampal synaptic plasticity.