Mixture of Peanut Skin Extract, Geniposide, and Isoquercitrin Improves the Hepatic Lipid Accumulation of Mice via Modification of Gut Microbiota Homeostasis and the TLR4 and AMPK Signaling Pathways.

Metabolic-dysfunction-associated steatotic liver disease (MASLD, formerly known as NAFLD) is a global chronic liver disease, and no licensed drugs are currently available for its treatment. The incidence of MASLD is increasing, which could lead to a huge clinical and economic burden. As a multifactorial disease, MASLD involves a complex set of metabolic changes, and many monotherapies for it are not clinically effective. Therefore, combination therapies using multiple drugs are emerging, with the advantages of improving drug efficacy and reducing side effects. Peanut skin extract (PSE), geniposide (GEN), and isoquercitrin (IQ) are three natural antiaging components or compounds. In this study, the preventive effects of individual PSE, GEN, and IQ in comparison with the effects of their mixture (MPGI) were examined in a mouse model of high-fat-feed-induced MASLD. The results showed that MPGI could significantly reduce the body and liver weights of mice and improve hepatic steatosis and liver function indicators. Further mechanistic studies showed that PSE, GEN, and IQ worked together by reducing inflammation, modulating the intestinal flora, and regulating the TLR4/NF-κB, AMPK/ACC/CPT1, and AMPK/UKL1/LC3B signaling pathways. It is a promising therapeutic method for preventing MASLD.

A new gentiopicroside derivative improves cognitive deficits of AD mice via activation of Wnt signaling pathway and regulation of gut microbiota homeostasis.

BACKGROUND: In our previous study, we found that gentiopicroside (GPS) isolated from Gentiana rigescens Franch has a significant antiaging activity via regulation of mitophagy and oxidative stress. In order to increase the anti-aging activity of GPS, several compounds based on the chemical structure of GPS were synthesized and evaluated for bioactivity with yeast replicative lifespan assay, and 2H-gentiopicroside (2H-GPS) as leading compound was selected for AD treatment. PURPOSE AND METHODS: To investigate whether 2H-GPS has anti- Alzheimer's disease effects, we used D-galactose (Dgal)-induced model mice to evaluate the effect of 2H-GPS on AD mice. Furthermore, we explored the action mechanism of this compound with RT-PCR, Western Blot, ELISA and 16S rRNA gene sequence analysis. RESULTS: Memory dysfunction and reduction in the number of neurons in the brain of mice were observed in Dgal treated group. These symptoms of AD mice were significantly relieved by administering 2H-GPS and donepezil (Done), respectively. In the Dgal only treated group, the protein levels of ß-catenin, REST and phosphorylated GSK-3ß, involved in the Wnt signaling pathway were significantly decreased, whereas the protein levels of GSK-3ß, Tau, phosphorylated Tau, P35 and PEN-2 were significantly increased. Importantly, treatment with 2H-GPS resulted in restoration of memory dysfunction and levels of these proteins. Furthermore, the composition of the gut microbiota after 2H-GPS administration was explored through 16S rRNA gene sequence analysis. Moreover, the mice, in which depleted gut microbiota with antibiotic cocktail (ABX), were used for evaluation of whether the gut microbiota is involved to the effect of 2H-GPS. Significant changes in gut microbiota composition were observed between AD and 2H-GPS-treated AD mice, and ABX partially eliminated the AD-restoring effect of 2H-GPS. CONCLUSION: 2H-GPS improves the symptoms of AD mice through combination of the regulation of Wnt signaling pathway and the microbiota-gut-brain axis, and the mechanism of action of 2H-GPS is distinct from that of Done.

Gastrodin From Gastrodia elata Enhances Cognitive Function and Neuroprotection of AD Mice via the Regulation of Gut Microbiota Composition and Inhibition of Neuron Inflammation.

Gastrodin (Gas) is known to exhibit neuroprotective effects in Alzheimer's disease (AD). However, the detailed mechanism of action is still unclear. In the present study, we focused on the microbiome-gut-brain axis to investigate the mechanism of action of Gas using a D-galactose (Dgal)-induced AD model. Gas reversed the memory dysfunction of Dgal-administered mice. Neurons in the cerebral cortex and hippocampus were reduced in the Dgal-administered group, and the decrease of neurons was suppressed in 90 and 210 mg/kg Gas treatment groups. 16S rRNA sequence analysis was carried out to explore the composition of gut microbiota in fecal samples of mice. Gas treatment had a positive correlation with Firmicutes and had a negative correlation with Cyanobacteria, Proteobacteria, and Deferribaceters. Importantly, the LPS and proinflammatory cytokines in the brain increased in Dgal-administered mice, but these parameters recovered to normal levels after oral administration of Gas. To determine whether the microbiota-gut-brain axis is involved in the neuroprotective effect of Gas, the mice were given antibiotic cocktail before and during the trial period to decrease the gut microbiota of mice. The antibiotic cocktail partially eliminated the neuroprotective effect of Gas by changing the gut microbiome composition. These results indicated that Gas improves the memory of the AD mouse model via partly targeting the microbiota-gut-brain axis and mitigating neuron inflammation.

Isoquercitrin from Apocynum venetum L. produces an anti-obesity effect on obese mice by targeting C-1-tetrahydrofolate synthase, carbonyl reductase, and glutathione S-transferase P and modification of the AMPK/SREBP-1c/FAS/CD36 signaling pathway in mice in vivo.

In the present study, mice with high-fat-diet-induced obesity were used in investigating the anti-obesity effects of an aqueous extract and isoquercitrin from Apocynum venetum L. The aqueous extract and the signal molecule isoquercitrin significantly reduced the body weight gain, food intake, water consumption, and fasting blood glucose, plasma triglyceride and total cholesterol levels of the obese mice. Furthermore, the mechanism of action of isoquercitrin was explored through RT-PCR analyses and uptake experiments of adenosine 5'-monophosphate-activated protein kinase (AMPK) and sterol regulatory-element binding protein (SREBP-1c) inhibitors and glucose. The indexes of SREBP-1c, fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD), and cluster of differentiation 36 (CD36) in obese mice significantly increased but returned to normal levels after the administration of isoquercitrin. Meanwhile, the anti-obesity effect of isoquercitrin was diminished by the inhibitors of AMPK and SREBP-1c. In addition, intestinal glucose uptake in normal mice was significantly inhibited after the oral administration of isoquercitrin. Moreover, 2D gel electrophoresis based proteome-wide cellular thermal shift assay (CETSA) showed that the potential target proteins of isoquercitrin were C-1-tetrahydrofolate synthase, carbonyl reductase, and glutathione S-transferase P. These results suggested that isoquercitrin produces an anti-obesity effect by targeting the above-mentioned proteins and regulating the AMPK/SREBP-1c signaling pathway and potentially prevents obesity and obesity-related metabolic disorders.

Protocatechuic acid ameliorates neurobehavioral deficits via suppression of oxidative damage, inflammation, caspase-3 and acetylcholinesterase activities in diabetic rats.

Clinical and experimental data have demonstrated that diabetes is associated with neurological complications. Protocatechuic acid (PCA) is a phenolic phytochemical widely reported to possess antidiabetic property. However, there is no scientific information on the influence of PCA on diabetes-induced neurotoxicity. The present study aimed at investigating the neuroprotective mechanism of PCA in streptozotozin (STZ)-induced type 1 diabetic rats orally treated with PCA (50 mg/kg body weight) or glibenclamide (5 mg/kg body weight) for 45 consecutive days. Locomotor behavior was analyzed using video-tracking software during the 8-min trial in a novel environment whereas the pancreas, cerebrum and cerebellum of the rats were processed for biochemical analyses. Results showed that treatment of diabetic rats with PCA at 50 mg/kg significantly (p < 0.05) improved the locomotor and motor activities including the average speed, total time mobile, distance travelled, body rotation, turn angle, forelimb grip and grooming when compared with untreated diabetic rats. Moreover, the prevention of diabetes-mediated increase in acetylcholinesterase activity, biomarkers of inflammatory and oxidative stress as well as caspase 3 activity by PCA treatment was accompanied by improved pancreatic, cerebral and cerebellar architectures. Collectively, the neuroprotective mechanisms of PCA is related to its antioxidant, anti-inflammatory and anti-apoptotic activities.

Impact of prepubertal exposure to dietary protocatechuic acid on the hypothalamic-pituitary-testicular axis in rats.

Protocatechuic acid (PCA; 3, 4-dihydroxybenzoic acid) is a phenolic compound widely found in many edible fruits, vegetables, grape wine and plant-derived beverages. The present study investigated the impact of PCA on the hypothalamic-pituitary-testicular axis of rats orally treated with PCA during the period of prepubertal development to adulthood. Protocatechuic acid was administered to prepubertal male rats at doses of 0, 5, 10, 50 and 100 mg/kg body for 45 consecutive days. The results revealed no treatment-related changes in the body weight gain and organo-somatic indices of the hypothalamus, testes, epididymis, prostate gland and seminal vesicle in rats administered with PCA when compared with control. However, prepubertal exposure to PCA significantly enhanced antioxidant enzyme activities and glutathione level whereas it markedly decreased biomarkers of inflammation and oxidative stress in the hypothalamus, testes and epididymis of the treated rats. Protocatechuic acid significantly increased circulatory concentrations of luteinizing hormone and follicle-stimulating hormone with concomitant increase in serum and intra-testicular testosterone levels. Moreover, PCA-treated rats exhibited significant increase in marker enzymes of testicular function namely acid phosphatase, alkaline phosphatase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase without statistically significant increase in spermatogenesis and sperm functional characteristics including sperm count, motility and viability. Light microscopic examination of the hypothalamus, testes and epididymis of rats treated with PCA showed histo-architectures similar to control. In conclusion, prepubertal exposure to PCA is safe and positively impacted reproductive function at sexual maturity in male rats. The observed beneficial effects of PCA is related to its anti-inflammatory and redox regulatory mechanisms.