Geraniin exerts cytoprotective effect against cellular oxidative stress by upregulation of Nrf2-mediated antioxidant enzyme expression via PI3K/AKT and ERK1/2 pathway

Geraniin restricts inflammasome activation and macrophage pyroptosis by preventing the interaction between ASC and NLRP3 to exert anti-inflammatory effects

Geraniin, a chemical component of the traditional Chinese medicine geranii herba, possesses anti-inflammatory and anti-oxidative activities. However, its anti-inflammatory role in managing NLRP3 inflammasome and pyroptosis remains to be elucidated. To investigate the anti-inflammation mechanism of geraniin, LPS-primed macrophages were incubated with classical activators of NLRP3 inflammasome (such as ATP, Nigericin, or MSU crystals), and MSU crystals were injected into the ankle joints of mice to establish an acute gouty arthritis model. The propidium iodide (PI) staining results showed that geraniin could restrain cell death in the ATP- or nigericin-stimulated bone marrow-derived macrophages (BMDMs). Geraniin decreased the release of lactate dehydrogenase (LDH) and interleukin (IL)-1β from cytoplasm to cell supernatant. Geraniin also inhibited the expression of caspase-1 p20, IL-1β in cell supernatant and N-terminal of gasdermin D (GSDMD-NT) while blocking the oligomerization of ASC to form speck. The inhibitory effects of geraniin on caspase-1 p20, IL-1β, GSDMD-NT, and ASC speck were not observed in NLRP3 knockout (NLRP3-/-) BMDMs. Hence, the resistance of geraniin to inflammasome and pyroptosis was contingent upon NLRP3 presence. Geraniin reduced reactive oxygen species (ROS) production and maintained mitochondrial membrane potential while preventing interaction between ASC and NLRP3 protein. Additionally, geraniin diminished MSU crystal-induced mouse ankle joint swelling and IL-1β expression. Geraniin blocked the recruitment of neutrophils and macrophages to the synovium of joints. Our results demonstrate that geraniin prevents the assembly of ASC and NLRP3 through its antioxidant effect, thereby inhibiting inflammasome activation, pyroptosis, and IL-1β release to provide potential insights for gouty arthritis targeted therapy.

Protective effects of triptolide against oxidative stress in retinal pigment epithelium cells via the PI3K/AKT/Nrf2 pathway: a network pharmacological method and experimental validation

PURPOSE

Among aging adults, age-related macular degeneration (AMD), is a prevalent cause of blindness. Nevertheless, its progression may be halted by antioxidation in retinal pigment epithelium (RPE). The primary effective constituent of Tripterygium wilfordii Hook. F., triptolide (TP), has demonstrated anti-inflammatory, antiproliferative, and antioxidant properties. The mechanics of the protective effect of triptolide against the oxidative damage in retinal pigment epithelial (RPE) were assessed in this study.

METHODS

ARPE-19 cells were pretreated with TP, and then exposed to sodium iodate (SI). First, cell viability was assessed using CCK-8. Subsequently, we measured indicators for cell oxidation including reactive oxygen species (ROS), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA). Then, we used network pharmacological analysis and molecular docking to explore the signaling pathway of TP. Last, we used western blot, ELISA, and immunofluorescence assays to clarify the potential mechanistic pathways.

RESULTS

The network pharmacology data suggested that TP may inhibit AMD by regulating the PI3K/Akt signaling pathway. Experimental results showed that the potential mechanism is that it regulates the PI3K/Akt pathway and promotes Nrf2 phosphorylation and activation, thereby raising the level of antioxidant factors (HO-1, NQO1) and reducing the generation of ROS, which inhibit oxidative damage.

CONCLUSION

Our findings suggested that the effect of TP on SI-exposed RPE cells principally relies on the regulation of oxidative stress through the PI3K/Akt/Nrf2 signaling pathway.

Byrsonima sericea Ethanol Extract Protected PC12 Cells from the Oxidative Stress and Apoptosis Induced by 6-Hydroxydopamine

Parkinson's disease is characterized by the progressive loss of dopaminergic neurons in the nigrostriatal pathway and oxidative stress is one of the main mechanisms that lead to neuronal death in this disease. Previous studies have shown antioxidant activity from the leaves of Byrsonima sericea, a plant of the Malpighiaceae family. This study aimed to evaluate the cytoprotective activity of the B. sericea ethanolic extract (BSEE) against the cytotoxicity induced by 6-hydroxydopamine (6-OHDA) in PC12 cells, an in vitro model of parkinsonism. The identification of phenolic compounds in the extract by HPLC-DAD revealed the presence of geraniin, rutin, isoquercetin, kaempferol 3-O-β-rutinoside, and quercetin. The BSEE (75-300 µg/mL) protected PC12 cells from toxicity induced by 6-OHDA (25 µg/mL), protected cell membrane integrity and showed antioxidant activity. BSEE was able to decrease nitrite levels, glutathione depletion, and protect cells from 6-OHDA-induced apoptosis. Thus, we suggest that the BSEE can be explored as a possible cytoprotective agent for Parkinson's disease due to its high antioxidant capacity and anti-apoptotic action.

Securinega suffruticosa extract alleviates atopy-like lesions in NC/Nga mice via inhibition of the JAK1-STAT1/3 pathway

Securinega suffruticosa (SS) has well-known antioxidant, anti-vascular inflammation, and anti-bone resorption effects; however, the effects of SS in atopic dermatitis (AD) remain unknown. We examined the effects of SS on AD via application of Dermatophagoides farinae extract (DfE) to the ears and skin of NC/Nga mice. As a result of SS administration, DfE-induced AD mice had reduced ear thickness, epidermal thickness, scratching behavior, and transepidermal water loss. The serum levels of immunoglobulin E and thymic interstitial lymphopoietin (TSLP) were reduced by SS application. SS decreased mast cell and eosinophil recruitment to skin lesions. Phosphorylation of signal transducer and activation of transcription (STAT)1, STAT3, and Janus kinase 1 were reduced in the skin tissue of SS-administered mice, and downregulated filaggrin was restored. SS reduced the levels of interleukin-6, regulated on activation, normal T cell expressed and secreted chemokine, and TSLP in interferon-γ/tumor necrosis factor-α-induced keratinocytes. The main components of SS were rutin and geraniin. These study results indicated that SS extract attenuated AD and has potential as a therapeutic natural product candidate for AD.

Geraniin targeting CaMKK2 inhibits lipid accumulation in 3T3-L1 adipocytes by suppressing lipogenesis

Obesity has become a worldwide burden and is associated with severe medical complications. Geraniin is a polyphenolic compound that has a wide range of bioactive properties. There is also evidence to support its pharmacological effects on improving lipid accumulation and obesity. This research investigates the effect of geraniin on lipid accumulation in adipocytes and the underlying mechanism. Mature adipocytes were differentiated from immature 3T3-L1 cells. Oil Red O staining and a triglyceride content determination were conducted to evaluate the intracellular lipid accumulation. Molecular docking studies were performed to determine the interaction between geraniin and the key proteins. Western blotting was used to detect the expression of lipogenic enzymes and transcription factors. Geraniin dose-dependently inhibited lipid accumulation in adipocytes by reducing the expression of fatty acid synthase and increasing the phosphorylation level of acetyl-coenzyme A carboxylase. Moreover, geraniin promoted the phosphorylation of AMP-activated protein kinase (AMPK) and further reduced the expression of lipogenic transcription factors (peroxisome proliferator-activated receptor gamma and CCAAT/enhancer binding protein alpha). The expression of the calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) was increased by the geraniin administration. The molecular docking study demonstrated that geraniin can interact with CaMKK2, which is an upstream kinase of AMPK. A selective CaMKK2 inhibitor reversed the suppressive effect of geraniin on lipogenesis. Geraniin targeted CaMKK2 to inhibit lipid accumulation in 3T3-L1 adipocytes by suppressing lipogenesis, and this supports its potential as a candidate natural anti-obesity drug.

Integration of Transcriptomics and Microbiomics Reveals the Responses of Bellamya aeruginosa to Toxic Cyanobacteria

Frequent outbreaks of harmful cyanobacterial blooms and the cyanotoxins they produce not only seriously jeopardize the health of freshwater ecosystems but also directly affect the survival of aquatic organisms. In this study, the dynamic characteristics and response patterns of transcriptomes and gut microbiomes in gastropod Bellamya aeruginosa were investigated to explore the underlying response mechanisms to toxic cyanobacterial exposure. The results showed that toxic cyanobacteria exposure induced overall hepatopancreatic transcriptome changes. A total of 2128 differentially expressed genes were identified at different exposure stages, which were mainly related to antioxidation, immunity, and metabolism of energy substances. In the early phase (the first 7 days of exposure), the immune system may notably be the primary means of resistance to toxin stress, and it performs apoptosis to kill damaged cells. In the later phase (the last 7 days of exposure), oxidative stress and the degradation activities of exogenous substances play a dominant role, and nutrient substance metabolism provides energy to the body throughout the process. Microbiomic analysis showed that toxic cyanobacteria increased the diversity of gut microbiota, enhanced interactions between gut microbiota, and altered microbiota function. In addition, the changes in gut microbiota were correlated with the expression levels of antioxidant-, immune-, metabolic-related differentially expressed genes. These results provide a comprehensive understanding of gastropods and intestinal microbiota response to toxic cyanobacterial stress.

Effects of in ovo feeding of chlorogenic acid on antioxidant capacity of postnatal broilers

In this study, chlorogenic acid (CGA) was injected into the amniotic cavity of chicken embryos to study the effects of in ovo feeding of CGA on the antioxidant capacity of postnatal broilers. On the 17th day of embryonic age, a total of 300 healthy broiler fertile eggs with similar weights were randomly subjected to five groups as follows; in ovo injection with 0.5 ml CGA at 4 mg/egg (4CGA) or 7 mg/egg (7CGA) or 10 mg/egg (10CGA), or sham-injection with saline (positive control, PC) or no injection (negative control, NC). Each group had six replicates of ten embryos. Six healthy chicks with similar body weights hatched from each replicate were selected and reared until heat stress treatment (35°C ± 1°C, 8 h/d) at 28-42 days of age. The results showed that there was no significant difference in the hatching rate between the groups (p > 0.05). After heat stress treatment, 4CGA group showed an improved intestinal morphology which was demonstrated by a higher villus height in the duodenum and a higher villus height/crypt depth ratio in the jejunum, compared with the NC group (p < 0.05). The antioxidant capacity of chickens was improved by in ovo feeding of CGA since 4CGA decreased the plasma content of malondialdehyde (MDA) (p < 0.05), whereas, it increased the superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities compared with NC group (p < 0.05). Also, the MDA content of the different injection groups had a quadratic effect, with the 4CGA group having the lowest MDA content (P _quadratic < 0.05). In the duodenum, 4CGA injection significantly increased the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (H O -1), glutathione synthetase (GSS), and SOD1 compared to the NC and PC groups (p < 0.05). The mRNA expressions of glutathione reductase (GSR) and GPX7 were significantly increased in all CGA-treated groups compared with the PC group (p < 0.05), while the mRNA expression of CAT was significantly increased by 4CGA group than the NC group (p < 0.05). The mRNA expressions of epigenetic-related genes, ten eleven translocation 1 and 2 (Tet1 and Tet2), and DNA-methyltransferase 3 alpha (DNMT3A) in the duodenum of 4CGA injected group was significantly increased compared with the NC and PC groups (p < 0.05). The mRNA expressions of Nrf2, SOD1, and Tet2 showed a significant quadratic effects with the 4CGA group having the highest expression (P _quadratic < 0.05). In conclusion, in ovo feeding of CGA alleviated heat stress-induced intestinal oxidative damage. Injection with CGA of 4 mg/egg is considered most effective due to its actions in improving intestinal antioxidant capacity, especially in the duodenum. The antioxidant effects of in ovo CGA on postnatal heat-stressed broilers may be related to its regulation of epigenetic mechanisms. Thus, this study provides technical knowledge to support the in ovo feeding of CGA to alleviate oxidative stress in postnatal heat-stressed broilers.

Effect of Noni on Memory Impairment Induced by Hydrocortisone in Mice

Background. Oxidative stress and memory impairment have been implicated as common functional brain diseases. Nuclear factor E2-related factor 2 (Nrf2) is highly induced in oxidative stress, indicating that Nrf2 is an emerging target of memory therapy. This study aimed to investigate the effect of noni on brain memory impairment induced by hydrocortisone and its protective mechanism in mice. Methods. Male Kunming mice (n = 8/group) were given hydrocortisone by gastric gavage for 14 consecutive days to establish the memory impairment model, except for those in the control group. On the same day, the corresponding drugs were given by gastric gavage. The changes in ethology were examined. The brains were extracted and subjected to western blot analysis and biochemical analyses to assess the activities of antioxidative stress. Results. The middle- and high-dose noni groups exhibited ameliorated ethology, and the high-dose noni group exhibited increased cerebral protein expression of Nrf2, Kelch-like ECH-associated protein 1 (KEAP1), and haem oxygenase-1 (HO-1) compared to the model group. The arrangement of CA3 vertebral cells in the hippocampus of mice was slightly compact, and hyperchromasia and pyknosis were alleviated. Furthermore, biochemical analyses showed that the activities of enzymes related to oxidative stress in the high-dose noni group were increased. Conclusions. Noni might be a powerful antioxidant that can protect nerve cells and may possess potential benefits for the treatment of memory impairment.

Novel Flavan-3,4-diol vernicidin B from Toxicodendron Vernicifluum (Anacardiaceae) as potent antioxidant via IL-6/Nrf2 cross-talks pathways

BACKGROUND

Oxidative stress is considered to be a pathological factor of various neurodegenerative diseases. Studies have confirmed the antioxidant activity of T. vernicifluum. However, the main active components responsible for antioxidant activity remain unknown.

OBJECTIVE

The aim of this study is to explore the activities of vernicidin B on oxidative stress injury induced by H₂O₂ in SH-SY5Y cells, and the underlying mechanism of vernicidin B in oxidative stress-related neurological diseases is further discussed.

METHODS

Various separation methods were used to isolate and identify the compounds in an EtOAc extract of T. vernicifluum. The structures of the isolates were clarified by HR-TOF-MS and 1D/2D NMR data and compared with findings in previous literature. The MTT assay was used to evaluate the potential antioxidant activity of the isolated flavonoids. The apoptosis rate, mitochondrial reactive oxygen species (ROS) level and mitochondrial potential were measured by flow cytometry and fluorescence microscope. The levels of related proteins were detected by Western blotting.

RESULTS

Four new flavan-3,4-diols (1-4, vernicidins A-D) and 11 known flavonoids (5-15) were purified from the EtOAc extract of T. vernicifluum. Among these compounds, vernicidin B showed the most promising potential for protecting SH-SY5Y cells from H₂O₂-induced oxidative stress. Moreover, pretreatment with vernicidin B decreased ROS production and mitochondrial membrane potential and significantly attenuated H₂O₂-induced apoptosis in a dose-dependent manner. Mechanistically, the antioxidant stress activities of vernicidin B were confirmed to be related to the IL-6/Nrf2 cross-talks pathway and its downstream pathways, including PI3K/Akt/mToR-Gsk3β, JAK2/STAT3 and MAPKs.

CONCLUSIONS

Our findings suggested that vernicidin B can improve the oxidative stress injury induced by H₂O₂ through IL-6/Nrf2 cross-talks pathway, indicating that it may be a potential candidate drug for the treatment of oxidative stress-related neurodegenerative diseases.

Dexmedetomidine attenuates hypoxia-induced cardiomyocyte injury by promoting telomere/telomerase activity: Possible involvement of ERK1/2-Nrf2 signaling pathway

Dexmedetomidine (Dex), an α2-adrenergic receptor (α2-AR) agonist, possesses cardioprotection against ischaemic/hypoxic injury, but the exact mechanism is not fully elucidated. Since telomere/telomerase dysfunction is involved in myocardial ischemic damage, the present study aimed to investigate whether Dex ameliorates cobalt chloride (CoCl_2; a hypoxia mimic agent in vitro)-induced the damage of H9c2 cardiomyocytes by improving telomere/telomerase dysfunction and further explored the underlying mechanism focusing on ERK1/2-Nrf2 signaling pathway. Result showed that Dex increased cell viability, decreased apoptosis, and reduced cardiomyocyte hypertrophy as illustrated by the decreases in cell surface area and the biomarker levels for cardiac hypertrophy including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and myosin heavy chain β (β-MHC) mRNA and protein in CoCl₂ -exposed H9c2 cells. Intriguingly, Dex increased the telomere length and telomerase activity as well as telomere reverse transcriptase (TERT) protein and mRNA levels in H9c2 cells exposed to CoCl₂ , indicating that Dex promotes telomere/telomerase function under hypoxia. In addition, Dex remarkably diminished the ROS generation, reduced MDA content, and increased antioxidative signaling as evidenced by the increases in SOD and GSH-Px activities. Furthermore, Dex increased the ratio of P-ERK1/2/T-ERK1/2 and P-Nrf2/T-Nrf2 and enhanced Nrf2 nuclear translocation in CoCl₂ -subjected H9c2 cells, suggesting that Dex promotes the activation of the ERK1/2-Nrf2 signaling pathway. These novel findings indicated that Dex attenuates myocardial ischemic damage and reduces myocardial hypertrophy by promoting telomere/telomerase function, which may be associated with the activation of the ERK1/2-Nrf2 signaling pathway in vitro. This article is protected by copyright. All rights reserved.

Polyphenols extracted from Shanxi-aged vinegar exert hypolipidemic effects on OA-induced HepG2 cells via the PPARα-LXRα-ABCA1 pathway

Hyperlipidemia is one of the key risk factors causing many chronic diseases, and lowering blood lipid levels can prevent many diseases. In this paper, a hyperlipidemic cell model of oleic acid (OA) induced hepatocellular carcinoma cells (HepG2) was established using polyphenols extracted from Shanxi-aged vinegar (SAVEP). The effects of SAVEP on nuclear damage, mitochondrial membrane potential, apoptosis, cellular lipid deposition, and lipid metabolism protein expression in HepG2 hyperlipidemic cells were examined to investigate the lipid-lowering mechanism of SAVEP at the cellular level. The results showed that SAVEP could reduce the content of TC/TG index, repair the nuclear damage, reduce lipid accumulation and finally decrease the rate of apoptosis by up-regulating the expression of key proteins such as PPARα, LXRα, and ABCA1 in the process of lipid metabolism. PRACTICAL APPLICATIONS: In this thesis, the hypolipidemic activity of polyphenol extracts from Shanxi-aged vinegar was analyzed on the level of HepG2 cells. The hypolipidemic mechanism of oxidative stress, lipid metabolism and inflammatory stress was also elucidated. It provided a theoretical basis for the in-depth understanding of the hypolipidemic health effects of Shanxi-aged vinegar.

The sequencing and characterization of chloroplast genome of Geranium sibiricum Linne

The complete chloroplast genome of Geranium sibiricum Linne. was sequenced, assembled and annotated. It is a circular form of 150,656 bp in length, which was separated into four distinct regions, a large single copy (LSC) of 73,862 bp, a small single copy region (SSC) of 52,666 bp, two inverted repeats (IR) of 12,064bp. A total of 124 genes were predicted, of which, 87 encode proteins, 4 rRNA, 33 tRNA. The evolutionary history was inferred using Maximum Likelihood method, and the result indicates that G. sibiricum was grouped within Geraniaceae, and comprised a clade with Geranium palmatum under 100% Bootstrap value.

Antimutagenic, Cytoprotective and Antioxidant Properties of Ficus deltoidea Aqueous Extract In Vitro

Ficus deltoidea var. deltoidea is used as traditional medicine for diabetes, inflammation, and nociception. However, the antimutagenic potential and cytoprotective effects of this plant remain unknown. In this study, the mutagenic and antimutagenic activities of F. deltoidea aqueous extract (FDD) on both Salmonella typhimurium TA 98 and TA 100 strains were assessed using Salmonella mutagenicity assay (Ames test). Then, the cytoprotective potential of FDD on menadione-induced oxidative stress was determined in a V79 mouse lung fibroblast cell line. The ferric-reducing antioxidant power (FRAP) assay was conducted to evaluate FDD antioxidant capacity. Results showed that FDD (up to 50 mg/mL) did not exhibit a mutagenic effect on either TA 98 or TA 100 strains. Notably, FDD decreased the revertant colony count induced by 2-aminoanthracene in both strains in the presence of metabolic activation (p < 0.05). Additionally, pretreatment of FDD (50 and 100 µg/mL) demonstrated remarkable protection against menadione-induced oxidative stress in V79 cells significantly by decreasing superoxide anion level (p < 0.05). FDD at all concentrations tested (12.5–100 µg/mL) exhibited antioxidant power, suggesting the cytoprotective effect of FDD could be partly attributed to its antioxidant properties. This report highlights that F. deltoidea may provide a chemopreventive effect on mutagenic and oxidative stress inducers.

GC × GC-MS analysis and hypolipidemic effects of polyphenol extracts from Shanxi-aged vinegar in rats under a high fat diet

Oxidative stress, inflammation and gut microbiota disorders can be induced by long-term high-fat diets (HFD). In order to confirm that polyphenols can improve these symptoms, polyphenols from Shanxi-aged vinegar (SAVEP) were extracted, and the components were detected by Comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-MS). 41 polyphenols include 18 phenolic acids and 17 polyphenols, which have not been reported. The mechanism of SAVEP on oxidative stress and inflammatory stress induced by HFD in rats and its regulating effect on intestinal flora disorder were studied. The results showed that SAVEP could significantly improve the lipid, inflammatory stress and oxidative stress related indicators compared with the Model group ("Model" refers to the group that successfully constructed a hyperlipidemia model by feeding HFD without any drugs or SAVEP in subsequent experiments.). In addition, SAVEP decreased the Firmicutes/Bacteroidetes ratio compared with the Model group, and elevated the relative abundance of beneficial bacteria. Conclusively, SAVEP can alleviate the oxidative stress and inflammatory stress caused by HFD, improving intestinal microbial disorders. The Spearman's correlation analysis revealed that Desulfovibrio, Lactobacillus and Akkermansia were correlated negatively with all of the inflammatory indicators, whereas Ruminococcus was the opposite. These results suggest that SAVEP may be a novel strategy against oxidative stress and inflammation, restoring the normal microbial community ecology of the gut and the treatment of metabolic syndromes.

Antiosteoporosis effect of geraniin on ovariectomy-induced osteoporosis in experimental rats

Osteoporosis is a skeletal condition that is characterized by decreasing bone density and deteriorating bone mass. The plant-based phytoconstituent such as geraniin possesses better therapeutic potentials in biomedical field. In the current experimental study, we planned to scrutinize the therapeutic potential of geraniin against ovariectomy (OVX)-induced osteoporosis in rats and find the possible mechanism. Healthy Sprague Dawley rats were randomized into six groups and subjected to geraniin and alendronate (ALN) treatment for 10 weeks. Body weight, uterus, femur weight, bone biochemical, bone turnover markers, inflammatory cytokine, calcium, phosphorus, vitamin D (Vit D), urine, hormones, and antioxidant level were estimated. Geraniin significantly (p < .001) reduced the level of bone turnover markers including beta-CrossLaps (β-CTx), ALN, osteocalcin (OC), alkaline phosphatase (ALP), and bone Gla protein (BGP); reduced the biomechanical parameters including maximum load, energy, stiffness, maximum stress, and Young's modulus; reduced the level of calcium (Ca) and phosphorus (P); and increased the level of vitamin D (Vit D) as compared with OVX-induced osteoporosis rats. Geraniin increased the level of bone structure parameters, namely bone mineral density, bone mineral content, tissue mineral density, bone volume fraction, and trabecular number; increased the level of osteoprotegerin (OPG) and OPG/RANKL; and reduced the level of receptor activator of nuclear factor kappa-Β ligand (RANKL). Geraniin significantly (p < .001) increased the level of glutathione (GSH) and reduced the level of malonaldehyde (MDA) in the liver, intestine, and bone of OVX-induced osteoporosis rats. Geraniin significantly (p < .001) decreased the level of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) pro-inflammatory cytokines. We also argue that geraniin could be an excellent candidate to treat and control bone-related disease or disorders.

Methylated Metabolites of Chicoric Acid Ameliorate Hydrogen Peroxide (H2O2)-Induced Oxidative Stress in HepG2 Cells

Chicoric acid (CA) can display health benefits as a dietary polyphenol. However, as CA is widely metabolized in vivo, the actual compounds responsible for its bioactivities are not entirely known. Herein, the major methylated metabolites of CA were isolated from an in vitro co-incubation system, and their structures were elucidated. The antioxidant activities of the monomethylated metabolites (M1) and dimethylated metabolites (M2) of CA were evaluated against H₂O₂-induced oxidative stress damage in HepG2 cells and compared to CA. The results indicated that both M1 and M2 had better antioxidant capacities than CA by increasing cell viability, improving mitochondrial function, and balancing cellular redox status. These compounds also prevented oxidative stress by mediating the Keap1/Nrf2 transcriptional pathway and downregulating enzyme activity. The current research indicates that the methylated metabolites of CA could potentially be the candidates that are responsible for the biological efficacies attributed to CA.

Chemoprotective Effects of Geraniin against Azoxymethane Induced Colorectal Cancer by Reduction of Inflammatory Reaction

The leading cause of cancer-related death is colorectal cancer, and inflammatory bowel disease is a risk factor for this disease. Azoxymethane (AOM) is a potent cancer inducer widely used in rats for colon cancer. The current study was scrutinizing the chemo-protective effect of geraniin against AOM induced colorectal cancer via alteration of oxidative stress and inflammatory cytokines. The rats were divided into different groups such as Group I: normal control, Group II geraniin (20 mg/kg), Group III: received AOM, Group IV-VI: AOM + geraniin (5, 10 and 20 mg/kg), respectively. All group of rats were received treatment for 16 weeks. At the end of the experimental study, the hepatic, biochemical, phase II antioxidant, antioxidant enzymes, cytokines, apoptosis and inflammatory mediators were estimated. Geraniin treatment significantly reduced tumor weight and enhanced body weight. Geraniin administration also altered the level of antioxidant parameters-superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR); phase I enzymes - cytochrome B5, cytochrome P450; phase II enzymes - Glutathione-S-Transferase (GST), UDP-Glucuronyl transferase (UDP-GT) respectively. Obtained results also demonstrate that geraniin treatment reduced the level of pro-inflammatory cytokines such as IL-2, IL-1α, IL-10, IL-1β, IL-4, IL-6, IL-12, IL-17A, IFN-γ, tumor necrosis factor-α, G-CSF, and GM-CSF. Geraniin also reduced the expression of IL-1α, IL-1β, IL-6, IFN-γ, G-CSF, and GM-CSF. On the basis of result we can conclude that geraniin reduced the colorectal cancer via inflammatory pathway.

Inhibitory Effect of Delphinidin on Oxidative Stress Induced by H2O2 in HepG2 Cells

Chronic liver diseases (CLDs) are correlated with oxidative stress induced by the accumulation of intracellular reactive oxygen species (ROS). In this study, we employed HepG2, a human liver carcinoma cell line containing many antioxidant enzymes, to explore the function of delphinidin against oxidative stress induced by H₂O₂ and to provide scientific data of the molecular mechanism. Cells were pretreated with different concentrations of delphinidin (10 μmol/L, 20 μmol/L, and 40 μmol/L) for 2 h before treatment with 750 μM H₂O₂ for 1 h. The results showed that H₂O₂ decreased the survival rate of HepG2 cells and increased the level of ROS, but delphinidin pretreatment could possess the opposite result. At the same time, the expression of Nrf2 was enhanced by the delphinidin pretreatment. This was because delphinidin promoted Nrf2 nuclear translocation and inhibited its degradation, which led to the increase expression of antioxidant protein HO-1 (Nrf2-related phase II enzyme heme oxygenase-1). Besides, we found that delphinidin could significantly alleviate the reduction of Nrf2 protein levels and the accumulation of intracellular ROS levels in Nrf2 knockdown HepG2 cells. In conclusion, our study suggested that delphinidin, as an effective antioxidant, protected HepG2 cells from oxidative stress by regulating the expression of Nrf2/HO-1.

Pleiotropic ameliorative effects of ellagitannin geraniin against metabolic syndrome induced by high-fat diet in rats

OBJECTIVES

Metabolic syndrome (MetS), a multiplex risk factor for cardiovascular disease and type 2 diabetes, is increasingly prevalent worldwide. Ellagitannin geraniin, a polyphenol found in the rind of rambutan (Nephelium lappaceum), has demonstrated therapeutic effects against metabolism dysfunction. The aim of this study was to characterize the metabolic effects and possible mechanism of geraniin in rats with MetS induced by a high-fat diet (HFD).

METHODS

MetS was induced in Sprague Dawley rats on an HFD, followed by a daily oral gavage of geraniin (25 mg/kg) for 4 wk. The outcomes of geraniin-treated rats were compared with those of untreated rats on either a control diet or an HFD and with rats with MetS treated with metformin on a daily basis (200 mg/kg).

RESULTS

The supplementation of geraniin ameliorated multiple metabolic abnormalities caused by HFD, including hypertension, impaired glucose and lipid metabolism, ectopic fat deposition in the visceral fat and liver, and disturbed antioxidant mechanism and inflammatory response. The benefits conferred by geraniin were comparable to metformin. Transcriptomic analysis revealed a profound influence of geraniin on the hepatic expression profiles. The lipid and steroid metabolic processes that were aberrantly activated by HFD were suppressed by geraniin. Based on the differential transcriptomes, geraniin also exerted a significant modulatory effect on the expression of mitochondrial genes, potentially influencing the mitochondrial activity and leading to the observed beneficial effects.

CONCLUSION

Geraniin supplementation mitigated metabolic anomalies of MetS in rats, making it an attractive drug candidate for further investigation.

Geraniin Protects PC12 Cells Against Aβ25-35-Mediated Neuronal Damage: Involvement of NF-κB and MAPK Signaling Pathways

β-amyloid peptide (Aβ) has been considered a critical factor that is associated with the development of oxidative stress and neuroinflammation in the pathogenesis of Alzheimer's disease. This study was performed to evaluate the effect of geraniin on Aβ_25-35-caused oxidative damage and neuroinflammatory response, and its underlying mechanism. Geraniin protected pheochromocytoma12 (PC12) cells from Aβ_25-35-mediated cell death by reducing oxidative stress and restoring cell cycle dysregulation. Moreover, geraniin markedly attenuated Aβ-triggered DNA injury that was partially associated with decreases in caspase-3 activity. Moreover, the compound significantly downregulated the release of neuroinflammatory factors. Upregulation of nuclear factor-κB activity was suppressed by geraniin, which was due to suppression of JNK, ERK1/2, and the p38 mitogen-activated protein kinase (MAPK) pathway. This was the first study to support further understanding of geraniin as a promising agent against neurotoxicity in the reduction of oxidative stress and neuroinflammation.

Punicalagin Protects Human Retinal Pigment Epithelium Cells from Ultraviolet Radiation-Induced Oxidative Damage by Activating Nrf2/HO-1 Signaling Pathway and Reducing Apoptosis

The oxidative damage of the retinal pigment epithelium (RPE) is the early event that underlies the pathogenesis of maculopathies. Numerous studies have shown that punicalagin (PUN), a polyphenol present in pomegranate, can protect several cell types from oxidative stress. Our study aims to establish if PUN protects RPE from UV radiation-induced oxidative damage. We used an experimental model which involves the use of a human-RPE cell line (ARPE-19) exposed to UV-A radiation for 1, 3, and 5 h. ARPE-19 cells were pre-treated with PUN (24 h) followed by UV-A irradiation; controls were treated identically, except for UV-A. Effects of pre-treatment with PUN on cell viability, intracellular reactive oxygen species ROS levels, modulation of Nrf2 and its antioxidant target genes, and finally apoptosis were examined. We found that pre-treatment with PUN: (1) antagonized the decrease in cell viability and reduced high levels of ROS associated with UV-A-induced oxidative stress; (2) activated Nrf2 signaling pathway by promoting Nrf2 nuclear translocation and upregulating its downstream antioxidant target genes (HO-1 and NQO1); (3) induced an anti-apoptotic effect by decreasing Bax/Bcl-2 ratio. These findings provide the first evidence that PUN can prevent UV-A-induced oxidative damage in RPE, offering itself as a possible antioxidant agent capable of contrasting degenerative eye diseases.

Betulinic acid improves insulin sensitivity, hyperglycemia, inflammation and oxidative stress in metabolic syndrome rats via PI3K/Akt pathways

This study investigated the influence of betulinic acid on high-fructose diet-induced metabolic syndrome in rats. Oral administration of betulinic acid significantly reversed high-fructose diet-mediated increase in body mass index and blood glucose. Furthermore, betulinic acid restored high-fructose diet-mediated alterations in metabolic hormones (insulin, leptin and adiponectin). Betulinic acid-mediated upregulation of protein kinase B (Akt) and phosphoinositde-3 kinase (PI3K) anulled high-fructose diet mediated depletion. Also, elevated tumour necrosis factor-α, interleukin-6 and -8 were significantly lowered. Administration of betulinic acid restored high-fructose diet-mediated increase in the levels of lipid profile parameters and indices of atherosclerosis, cardiac and cardiovascular diseases. High-fructose diet-mediated decrease in activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase) and increase in oxidative stress biomarkers (reduced glutathione, lipid peroxidation products, protein oxidation and fragmented DNA) were significantly restored by the phenolic acids. Conclusively, betulinic acid improves insulin sensitivity, elevated blood glucose, inflammation and dyslipidaemia and oxidative stress in high-fructose diet-induced metabolic syndrome through the PI#Kand Akt pathways .

Juglanin administration protects skin against UVB‑induced injury by reducing Nrf2‑dependent ROS generation

Extensive solar ultraviolet B (UVB) exposure of the skin results in inflammation and oxidative stress, which may contribute to skin cancer. Natural products have attracted attention for their role in the effective treatment of cutaneous neoplasia. Juglanin is purified from the crude extract of Polygonum aviculare, exhibiting anti-oxidant, anti-inflammatory and anti-cancer activities. Jugalanin was used in the current study to investigate whether it may ameliorate UVB irradiation-induced skin damage by reducing oxidative stress and suppressing the inflammatory response in vivo and in vitro. In the present study, hairless mice were exposed to UVB irradiation in the absence or presence of juglanin administration for 10 weeks. The findings indicated that juglanin inhibited UVB-induced hyperplasia and decreased infiltration in the skin of mice. UVB exposure-induced oxidative stress in mice and cells was inhibited by juglanin via enhancing anti-oxidant activity. Additionally, juglanin markedly reduced pro-inflammatory cytokine release, including cyclic oxidase 2, interleukin-1β and tumor necrosis factor-α, triggered by chronic UVB irradiation. Juglanin-ameliorated skin damage was associated with its suppression of mitogen activated protein kinases (MAPKs), including p38, extracellular signal regulated 1/2, and c-Jun N-terminal kinases, as well as nuclear factor (NF)-κB signaling pathways, which was dependent on nuclear factor-E2-related factor 2 (Nrf2)-modulated reactive oxygen species generation. Taken together, these data indicate that juglanin protected against UVB-triggered oxidative stress and inflammatory responses by suppressing MAPK and NF-κB activation via enhancing Nrf2 activity.

Modulation of cell signaling pathways by Phyllanthus amarus and its major constituents: potential role in the prevention and treatment of inflammation and cancer

The causal and functional connection between inflammation and cancer has become a subject of much research interest. Modulation of cell signaling pathways, such as those involving mitogen activated protein kinases (MAPKs), nuclear factor kappa β (NF-κB), phosphatidylinositol 3-kinase and protein kinase B (PI3K/Akt), and Wnt, and their outcomes play a fundamental role in inflammation and cancer. Activation of these cell signaling pathways can lead to various aspects of cancer-related inflammation. Hence, compounds able to modulate inflammation-related molecular targets are sought after in anticancer drug development programs. In recent years, plant extracts and their metabolites have been documented with potential in the prevention and treatment of cancer and inflammatory ailments. Plants possessing anticancer and anti-inflammatory properties due to their bioactive constituents have been reported to modulate the molecular and cellular pathways which are related to inflammation and cancer. In this review we focus on the flavonoids (astragalin, kaempferol, quercetin, rutin), lignans (phyllanthin, hypophyllanthin, and niranthin), tannins (corilagin, geraniin, ellagic acid, gallic acid), and triterpenes (lupeol, oleanolic acid, ursolic acid) of Phyllanthus amarus, which exert various anticancer and anti-inflammatory activities via perturbation of the NF-κB, MAPKs, PI3K/Akt, and Wnt signaling networks. Understanding the underlying mechanisms involved may help future research to develop drug candidates for prevention and new treatment for cancer and inflammatory diseases.

Enhancing the antioxidative effects of foods containing rutin and α-amino acids via the Maillard reaction: A model study focusing on rutin-lysine system

Rutin is a bioflavonoid found in many plants and derived foods, accordingly, rutin likely interacts with α-amino acids such as Lys, Ile, His or Glu to give Maillard reaction products (MRPs). The heated rutin-Lys system exhibited highest brown intensity and in vitro antioxidant activities. The 30-50 kDa rutin-Lys fraction had higher in vitro antioxidant activities than the other fractions, and at a dose of 0.4 mg/ml preserved over 90% cell viability for HepG2 cells exposed to H₂ O₂ . The dose-dependent protective effects against H₂ O₂ -induced oxidative stress of the rutin-Lys MRPs may involve the inhibition of reactive oxygen species generation, enhancement of the superoxide dismutase and catalase activities, along with the activation of the Nrf2-dependent pathway and upregulation of phase II antioxidant genes (including NQO1, HO-1, GCLG, and GCLM). PRACTICAL APPLICATIONS: Rutin is widely distributed in vegetables and grains. The Maillard reaction is a common reaction occurring during food processing, and produces Maillard reaction products (MRPs) with distinct processing and biological properties. This study shows that a 30-min thermal treatment at 120°C generates antioxidative MRPs in the rutin-Lys, rutin-His, rutin-Ile and rutin-Glu model systems, which can directly inhibit reactive oxygen species generation and enhance SOD and CAT activities while activating the Nrf2-dependent pathway and upregulating the expression of phase II detoxifying antioxidant genes. Therefore, for food systems containing phenolic antioxidants and proteins (such as rutin and Lys), one may enhance the antioxidant properties of these food systems through a 30-min thermal treatment at 120°C. Also, the resultant rutin-Lys MRPs may be isolated and used as commercial preparations of natural antioxidants.

Genistein protects intervertebral discs from degeneration via Nrf2-mediated antioxidant defense system: An in vitro and in vivo study

Oxidative stress has been reported to be closely associated with the development of intervertebral disc degeneration (IDD). IDD is one of the major causes of low back pain. Genistein (GES), one of the main isoflavones of soybean, has been shown to exert multiple biological functions on different diseases. Here, we tested the therapeutic potential of GES for IDD. In vitro experiments, we confirmed GES was nontoxic to rat nucleus pulposus cells (NPCs) within the concentration of 100 μM. Furthermore, GES was able to suppress apoptosis in tert-butyl hydroperoxide (TBHP)-treated NPCs. In the aspect of extracellular matrix (ECM), GES not only reduced metalloproteinase-13 (MMP-13) and a disintegrin-like and MMP thrombospondin type 1 motif 5 expression, but also increased aggrecan and type II collagen levels. Also, we found GES might rescue TBHP-induced NPCs degeneration by enhancing Nrf2-mediated antioxidant defense system. Silencing Nrf2 partly abolished the protective effects of GES on apoptosis and ECM disruption in TBHP-treated NPCs. Correspondingly, GES ameliorated IDD in a rat model by preserving morphology of degenerative intervertebral discs and promoting Nrf2 expression. To sum up, our study suggests that GES exerts protective effects in NPCs against degeneration and reveals the underlying mechanism of GES on Nrf2 activation in NPCs.

Effects of Proanthocyanidins on Arsenic Methylation Metabolism and Efflux in Human Hepatocytes L-02

This study investigated the effects of proanthocyanidins (PC) on arsenic methylation metabolism and efflux in human hepatocytes (L-02), as well as the relationships between PC and GSH, MRP1 and other molecules. Cells were randomly divided into blank control group, arsenic trioxide exposure group (ATO, As₂O₃, 25μmol/L), and PC-treated arsenic exposure group (10, 25, 50mg/L). After 24/48h, the contents of different forms of arsenic were determined, and the methylation indexes were calculated. Intracellular S-adenosyl methionine (SAM), arsenic (+3 oxidation state) methyltransferase (AS3MT), multidrug resistance-associated protein 1 (MRP1), and reduced glutathione (GSH) were ascertained. Changing trends were observed and the correlation between arsenic metabolism and efflux related factors and arsenic metabolites was analyzed. We observed that cells showed increased levels of content/constituent ratio of methyl arsenic, primary/secondary methylation index, methylation growth efficiency/rate, and the difference of methyl arsenic content in cells and culture medium (P<0.05, resp.). Compared with ATO exposure group, the intracellular SAM content in PC-treated group decreased, and the contents of GSH, AS3MT, and MRP1 increased (P<0.05, resp.). There was a positive correlation between the content of intracellular GSH/AS3MT and methyl arsenic. The content of MRP1 was positively correlated with the difference of methyl arsenic content in cell and culture medium; conversely, the SAM content was negatively correlated with intracellular methyl arsenic content (P<0.05, resp.). Taken together, these results prove that PC can promote arsenic methylation metabolism and efflux in L-02 cells, which may be related to the upregulation of GSH, MRP1, and AS3MT levels by PC.

Protective effects of Phyllanthus phillyreifolius extracts against hydrogen peroxide induced oxidative stress in HEK293 cells

Phyllanthus phillyreifolius, a plant species indigenous to Reunion Island, is used in folk medicine for treating diarrhea and as a diuretic. In the present study acetone and hydroethanol extracts of P. phillyreifolius were evaluated for their cytotoxicity and antioxidant effects using in vitro (TPC, ABTS, DPPH, FRAP, ORAC) and in cellulo (MTT, DCFH-DA, RT-qPCR) assays. Major compounds were evaluated using UPLC-QTOF-MS. MTT cell viability assay showed low cytotoxicity of extracts towards human embryonic kidney 293 (HEK293) cell line. Both extracts were rich in polyphenols (mainly ellagitannins) and showed high antioxidant potential and intracellular ROS decreasing effect. Preconditioning of HEK293 cells with extracts influenced gene expression of antioxidant enzymes, however ROS level decreasing effect was more related to their capacity to scavenge free radicals and with their reducing power. Strong antioxidant activity of extracts as well as the presence of geraniin supports the use of P. phillyreifolius in traditional medicine.

Assessment of Wound-Healing Properties of Medicinal Plants: The Case of Phyllanthus muellerianus

Phyllanthus muellerianus (Family Euphorbiaceae) is a shrub, which is widely distributed in West Africa and employed traditionally as a wound-healing agent especially in Ghana. The aim of the study was to determine the in vivo wound-healing activity of aqueous aerial part extract of P. muellerianus (PLE) and its major isolate, geraniin. Excision and incision wound models were used to determine the wound-healing activity. Wounds were treated with PLE (0.25, 0.5, and 1% w/w) and geraniin (0.1, 0.2, and 0.4% w/w) aqueous creams. PLE and geraniin significantly (p < 0.001) increased wound contraction rate and hydroxyproline production compared to untreated wounds. Histological studies of wound tissues showed high levels of fibroblasts and increased collagen content and cross-linking in PLE and geraniin-treated wound tissues. Immuno-histochemical investigations revealed high levels of TGF-β₁ in PLE and geraniin-treated wound tissues compared to the untreated wound tissues. Tensile strength of incised wounds was significantly (p < 0.05) high in PLE and geraniin-treated wounds. PLE (0.1–100 μg/mL) significantly (p < 0.001) reduce LDH release from HaCaT-keratinocytes compared to the untreated cells. PLE and geraniin possess wound healing and cytoprotective effect.

Ferulic acid protects against heat stress-induced intestinal epithelial barrier dysfunction in IEC-6 cells via the PI3K/Akt-mediated Nrf2/HO-1 signaling pathway

PURPOSE

Intestinal epithelial barrier dysfunction is crucial in the pathogenesis of intestinal and systemic diseases. Ferulic acid (FA) possesses promising antioxidant activities. In a previous study, we demonstrated potentially protective effects of FA against heat stress-induced intestinal epithelial barrier dysfunction in IEC-6 cells. However, the underlying mechanisms are unclear. The present study aimed to elucidate whether FA protects IEC-6 cells from heat stress-induced intestinal epithelial barrier dysfunction via antioxidative mechanisms.

MATERIALS AND METHODS

IEC-6 cells were pretreated with FA prior to hyperthermia exposure at 42 °C for 6 h, and the levels of intracellular reactive oxygen species (ROS), malondialdehyde (MDA), nitrogen oxide (NO), and superoxide dismutase (SOD) activity were analyzed. The intestinal epithelial barrier function was determined by transepithelial electrical resistance (TER) values and 4-kDa fluorescein isothiocyanate-dextran (FD4) flux in IEC-6 cell monolayers. Expression of related proteins was detected by Western blotting.

RESULTS

FA suppressed heat stress-induced intestinal oxidative stress damage by reducing ROS, MDA and NO production, while enhancing SOD activity. Furthermore, FA treatment strengthened intestinal barrier function via increasing the phosphorylation levels of Akt, nuclear factor-erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) protein expression, which was reversed by zinc protoporphyrin (an HO-1 inhibitor). Additionally, LY294002, a specific PI3K/Akt inhibitor, significantly suppressed FA-induced Nrf2 nuclear translocation and HO-1 protein expression and inhibited FA-induced occludin and ZO-1 protein expression.

CONCLUSIONS

FA protected against heat stress-induced intestinal epithelial barrier dysfunction via activating the PI3K/Akt-mediated Nrf2/HO-1 signaling pathway in IEC-6 cells.

Cytoprotective effect exerted by geraniin in HepG2 cells is through microRNA mediated regulation of BACH-1 and HO-1

Geraniin, a hydrolysable tannin, used in traditional medicine in Southeast Asia, is known to exhibit various biological activities. As an antioxidant it is known to up-regulate phase II enzyme Heme oxygenase-1 (HO-1). However its mechanism is not clearly understood. Nuclear factor erythroid-derived 2 related factor 2 (Nrf-2) is transcriptionally up-regulated by Extracellular signal-regulated kinase (ERK) 1/2 and retained in nucleus due to inactivated Glycogen synthase kinase 3 beta (GSK-3β). Geraniin additionally down-regulates expression of microRNA 217 and 377 (miR-217 and miR-377) which target HO-1 mRNA. Expression of BTB and CNC homolog 1 (BACH-1), another regulator of HO-1, is also down-regulated by up-regulating microRNA 98 (miR-98), a negative regulator of BACH-1. Thus, geraniin up-regulates HO-1 expression both through activating its positive regulator Nrf-2 and by down-regulating its negative regulator BACH-1. Up-regulation of HO-1 also confers protection to HepG2 cells from tertiary butyl hydroperoxide (TBH) induced cytotoxicity.

Role of lncRNAs as prognostic markers of hepatic cancer and potential therapeutic targeting by S-adenosylmethionine via inhibiting PI3K/Akt signaling pathways

Hepatic cancer (HCC) is a well-identified dilemma throughout the world, and hence, the molecular mechanisms and strategy for preventive protection against this malignancy are critical. S-adenosylmethionine (SAM) is a unique methyl granter in vast reactions, including DNA methylation, and secures the genome against hypomethylation, which is a hallmark of tumors. Consequently, SAM may control the rate of gene expression. The objective of this investigation was to evaluate the expression of long noncoding RNAs (lncRNAs) transcript involved in hepatic tumorigenesis, including additional coding CEBPA (ecCEBPA) and urothelial carcinoma related 1 (UCA1), antioxidant enzymes transcripts, and relevant signaling pathway in diethylnitrosamine (DEN)-prompted HCC along with their conceivable targeting by SAM at different stages of HCC in rats. Our outcomes revealed that SAM particularly when given at the starting phase downregulates ecCEBPA and UCA1 gene transcripts and ameliorate histopathological alterations in DEN-initiated HCC. Interestingly, SAM attenuates DEN-induced upregulation of PI3K/Akt protein expression. However, SAM upregulates the antioxidant enzymes mRNA transcripts and effectively diminishing DNA oxidation. The results of a DNA fragmentation assay further support the capacity of SAM to ameliorate DEN-induced hepatic malignancy. These results revealed the role of ecCEBPA and UCA1 in HCC and suggest that these lncRNAs may be helpful as prognostic and analytical biomarkers of HCC. Curiously, SAM readily targets the studied genes via inhibiting PI3K/Akt signaling pathway, which should make SAM an appealing agent for both chemoprevention and treatment of HCC.

Juglone induces apoptosis and autophagy via modulation of mitogen-activated protein kinase pathways in human hepatocellular carcinoma cells

Juglone (JG), a naturally-occurring naphthoquinone of Manchurian walnut (Juglans mandshurica) was shown to inhibit proliferation in various tumor types. However, the molecular mechanisms of JG on the induction of apoptosis and autophagy in HepG2 cells have not been examined. Herein, we investigated that JG could inhibit cell proliferation by induction of G2/M phase arrest. Also, occurrence of apoptosis was closely related with loss of mitochondrial membrane potential, the changes of apoptosis-related proteins after treatment with JG. In addition, we found that JG caused autophagy, as evidenced by increased expressions of LC3-II and Beclin-1. Interestingly, inhibition of JG-induced autophagy by 3-methyladenine (3-MA) and wortmannin (WT) significantly decreased apoptosis, whereas the apoptosis inhibitor z-VAD-fmk slightly enhanced autophagy. Furthermore, the induction of autophagy and apoptosis was associated with activation of MAPK family members (p38 and JNK) and production of reactive oxygen species (ROS). Both JNK inhibitor (SP600125) and ROS scavenger (N-acetylcysteine, NAC) could attenuate JG-induced autophagy and apoptosis. However, the p38-specific inhibitor SB203580 enhanced autophagic and apoptotic death. Moreover, the ROS scavenger NAC prevented phosphorylation of both p38 and JNK. Collectively, our data revealed that JG induced G2/M phase arrest, apoptosis, and autophagy through the ROS-dependent signaling pathway.

Geraniin Protects High-Fat Diet-Induced Oxidative Stress in Sprague Dawley Rats

Geraniin, a hydrolysable polyphenol derived from Nephelium lappaceum L. fruit rind, has been shown to possess significant antioxidant activity in vitro and recently been recognized for its therapeutic potential in metabolic syndrome. This study investigated its antioxidative strength and protective effects on organs in high-fat diet (HFD)-induced rodents. Rats were fed HFD for 6 weeks to induce obesity, followed by 10 and 50 mg/kg of geraniin supplementation for 4 weeks to assess its protective potential. The control groups were maintained on standard rat chows and HFD for the same period. At the 10th week, oxidative status was assessed and the pancreas, liver, heart and aorta, kidney, and brain of the Sprague Dawley rats were harvested and subjected to pathological studies. HFD rats demonstrated changes in redox balance; increased protein carbonyl content, decreased levels of superoxide dismutase, glutathione peroxidase, and glutathione reductase with a reduction in the non-enzymatic antioxidant mechanisms and total antioxidant capacity, indicating a higher oxidative stress (OS) index. In addition, HFD rats demonstrated significant diet-induced changes particularly in the pancreas. Four-week oral geraniin supplementation, restored the OS observed in the HFD rats. It was able to restore OS biomarkers, serum antioxidants, and the glutathione redox balance (reduced glutathione/oxidized glutathione ratio) to levels comparable with that of the control group, particularly at dosage of 50 mg geraniin. Geraniin was not toxic to the HFD rats but exhibited protection against glucotoxicity and lipotoxicity particularly in the pancreas of the obese rodents. It is suggested that geraniin has the pharmaceutical potential to be developed as a supplement to primary drugs in the treatment of obesity and its pathophysiological sequels.

Terminalia chebula Retz. – an important medicinal plant

Ayurveda, whispered to be the ancient practice of healthcare existed and contributes a holistic approach to health, healing and longevity. Terminalia chebula Retz. is a popular plant and widely spread all over southern Asia. T. chebula is a native plant of India and its dried fruit is extensively used in various types of home remedies. Dried fruit of T. chebula contains high quantities phenolic compounds that consist of ellagic acid, gallic acid and chebulic acid. The fruit extract of T. chebula is known to display different biological properties like anticancer, anti-inflammatory, antioxidant, anti-protozoal, antimicrobial, hepato and renal protective activities, and in the management of metabolic syndrome. The phenolic active compounds might play vital role in the influence of biological activity. Fruit extract of T. chebula is widely employed as an important ingredient in various ayurvedic preparations like ‘Triphala’. This formulation is beneficial as detoxifying agent of the colon, purgative in chronic constipation, aids in digestion and as a body rejuvenator. The fruit has great medicinal significance and conventionally applied for the management of various illness conditions, such as sore throat, high cough, asthma, ulcers, gout, heart burn, vomiting, diarrhea, dysentery, bleeding piles and bladder diseases. It is also utilized as mild laxative, antispasmodic and stomachic. Because of these enormous medicinal properties, T. chebula is commonly termed as ‘King of Medicine’ in Tibet and can be called as a ‘wonder herb’. In the present review, recent advances in medicinal properties of T. chebula are discussed.

Hepatoprotective potential of Phyllanthus muellarianus leaf extract: studies on hepatic, oxidative stress and inflammatory biomarkers

CONTEXT

Leaves of Phyllanthus muellarianus (Kuntze) Exell. (Euphorbiacea) are widely used in the management of liver disorders in Nigeria. However, no there is no scientific validation to support this use.

OBJECTIVE

Hepatoprotective effect of Phyllanthus muellarianus aqueous leaf extract was investigated in acetaminophen-induced liver injury mice.

MATERIALS AND METHODS

Hepatoprotective effect of Phyllanthus muellarianus aqueous leaf extract was evaluated in acetaminophen-induced hepatic damage in Swiss albino mice using biomarkers of hepatocellular indices, oxidative stress, proinflammatory factors and lipid peroxidation. Mice received distilled water, 100, 200, or 400 mg/kg b.w of Phyllanthus muellarianus aqueous leaf extract, respectively, for seven days. Treatment groups were challenged with 300 mg/kg b.w of acetaminophen on the sixth day.

RESULTS

Oral administration of Phyllanthus muellarianus aqueous leaf extract significantly (p < 0.05) attenuates acetaminophen-mediated alterations in serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin and total bilirubin by 76.56, 85.41, 89.39, 82.77 and 78.38%. Similarly, acetaminophen-mediated decrease in activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase were significantly attenuated in the liver of mice by 85.10, 80.81, 80.45, 76.23 and 95.22%, respectively. Increased levels of conjugated dienes, lipid hydroperoxides, malondialdehyde, protein carbonyl, fragmented DNA, tumor necrosis factor-α, interleukin-6 and -8 were significantly lowered by Phyllanthus muellarianus aqueous leaf extract.

CONCLUSION

Overall, results of this study show that Phyllanthus muellarianus halted acetaminophen-mediated hepatotoxicity due to its capability to enhance antioxidant enzymes.

Geraniin protects bone marrow‑derived mesenchymal stem cells against hydrogen peroxide‑induced cellular oxidative stress in vitro

Administration of bone marrow-derived mesenchymal stem cells (MSCs) has emerged as a potential therapeutic approach for the treatment of myocardial infarction (MI). However, the increase in reactive oxygen species (ROS) in ischemic cardiac tissue compromises the survival of transplanted MSCs, thus resulting in limited therapeutic efficiency. Therefore, strategies that attenuate oxidative stress-induced damage and enhance MSC viability are required. Geraniin has been reported to possess potent antioxidative activity and exert protective effects on numerous cell types under certain conditions. Therefore, geraniin may be considered a potential drug used to modulate MSC-based therapy for MI. In the present study, MSCs were pretreated with geraniin for 24 h and were exposed to hydrogen peroxide (H₂O₂) for 4 h. Cell apoptosis, intracellular ROS levels and mitochondrial membrane potential were measured using Annexin V-fluorescein isothiocyanate/ propidium iodide staining, the 2′,7′-dichlorodihydrofluorescein diacetate fluorescent probe and the membrane permeable dye JC-1, respectively. Glutathione and malondialdehyde levels were also investigated. The expression levels of apoptosis-associated proteins and proteins of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway were analyzed by western blotting. The results demonstrated that geraniin could significantly attenuate H₂O₂-induced cell damage by promoting MSC survival, reducing cellular ROS production and maintaining mitochondrial function. Furthermore, geraniin modulated the expression levels of phosphorylated-Akt in a time- and dose-dependent manner. The cytoprotective effects of geraniin were suppressed by LY294002, a specific PI3K inhibitor. In conclusion, the present study revealed that geraniin protects MSCs from H₂O₂-induced oxidative stress injury via the PI3K/Akt pathway. These findings indicated that cotreatment of MSCs with geraniin may optimize therapeutic efficacy for the clinical treatment of MI.

An increased autophagic flux contributes to the anti-inflammatory potential of urolithin A in macrophages

BACKGROUND

An extract of Phyllanthus muellerianus and its constituent geraniin have been reported to exert anti-inflammatory activity in vivo. However, orally consumed geraniin, an ellagitannin, shows low bioavailability and undergoes metabolization to urolithins by gut microbiota. This study aimed at comparing geraniin and urolithin A with respect to inhibition of M1 (LPS) polarization of murine J774.1 macrophages and shedding more light on possible underlying mechanisms.

METHODS

Photometric, fluorimetric as well as luminescence-based assays monitored production of reactive oxygen species (ROS) and nitric oxide (NO), cell viability or reporter gene expression. Western blot analyses and confocal microscopy showed abundance and localization of target proteins, respectively.

RESULTS

Urolithin A is a stronger inhibitor of M1 (LPS) macrophage polarization (production of NO, ROS and pro-inflammatory proteins) than geraniin. Urolithin A leads to an elevated autophagic flux in macrophages. Inhibition of autophagy in M1 (LPS) macrophages overcomes the suppressed nuclear translocation of p65 (NF-kB; nuclear factor kB), the reduced expression of pro-inflammatory genes as well as the diminished NO production brought about by urolithin A. The increased autophagic flux is furthermore associated with impaired Akt/mTOR (mammalian target of rapamycin) signaling in urolithin A-treated macrophages.

CONCLUSIONS AND GENERAL SIGNIFICANCE

Intestinal metabolization may boost the potential health benefit of widely consumed dietary ellagitannins, as suggested by side by side comparison of geraniin and urolithin A in M1(LPS) macrophages. Increased activity of the autophagic cellular recycling machinery aids the anti-inflammatory bioactivity of urolithin A.

Antioxidant effects of Geranium nepalense ethanol extract on H2O2-induced cytotoxicity in H9c2, SH-SY5Y, BEAS-2B, and HEK293

Oxidative damage leads to many diseases. In this study, we evaluated the antioxidant effects of 70% ethanol extract of Geranium nepalense (GNE) on hydrogen peroxide-induced cytotoxicity in cell lines: H9c2, SH-SY5Y, HEK293, and BEAS-2B. We determined the free radical scavenging activity of GNE using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and superoxide dismutase-like activities, as well as the polyphenol and flavonoid contents of GNE. The results showed that GNE scavenged DPPH and ABTS radicals in a dose-dependent manner. In addition, it contained abundant contents of total polyphenol and flavonoid contents and strongly suppressed cellular reactive oxygen species, thereby protecting H₂O₂-induced cytotoxicity in H9c2, SH-SY5Y, HEK293, and BEAS-2B cell lines. The powerful antioxidant activity exhibited by GNE, both in vitro and in cell systems, was attributed to its free radical scavenging activity. Therefore, GNE may be useful in preventing oxidative stress-induced diseases including Alzheimer's disease, respiratory inflammatory disease, and chronic kidney diseases.

Umbilical Cord MSCs Reverse D-Galactose-Induced Hepatic Mitochondrial Dysfunction via Activation of Nrf2/HO-1 Pathway

Mitochondria are the central hubs for cellular bioenergetics and are crucial to cell survival. It is well accepted that compromised mitochondrial function is linked with hepatocytes injury and contribute to progression of liver diseases. Despite the therapeutic potential of mesenchymal stem cells (MSCs) transplantation on hepatic disorders have been extensively investigated, the effects of MSCs on mitochondrial function in liver injury models remain unknown. Here we investigated the effects of treatment with umbilical cord (UC) MSC in a rat model of D-galactose (D-Gal) induced liver injury, characterized by organ damage, oxidative stress and mitochondrial dysfunction. Our results showed that UC-MSCs treatment significantly alleviated histological lesion and attenuated the elevation of liver biochemical markers, demonstrating its protective effects on D-Gal induced hepatic disorders. Mitochondria isolated from the liver of D-Gal models exhibited decreased antioxidant capacity as well as compromised bioenergetics functions, as shown by a loss of mitochondrial membrane potential, elevation of reactive oxygen species (ROS) production, reduction of mitochondrial respiration complexes and ATP decrement. Treatment of rats with UC-MSCs remarkably blunted these changes and rescued mitochondrial efficiency. Mechanistically, we found that the protective potential of UC-MSCs administration was mediated by nuclear factor-E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway, but not FOXO3a pathway. In conclusion, the attenuating effects of UC-MSCs on hepatic damage partially rely on normalizing mitochondrial function and preventing a state of energetic deficit via activation of Nrf2/HO-1 pathway.

Geraniin attenuates LPS-induced acute lung injury via inhibiting NF-κB and activating Nrf2 signaling pathways

Geraniin, a typical ellagitannin isolated from Phyllanthusurinaria Linn, has been reported to have anti-inflammatory effect. The aim of the study is to investigate the therapeutic effects of geraniin on LPS-induced acute lung injury (ALI) in mice. The mice were intranasal adminisration of LPS for 12 h. Geraniin was intra-peritoneal injection 1 h after LPS treatment. The results showed that geraniin significantly attenuated LPS-induced pathological changes in the lung. Geraniin also inhibited LPS-induced macrophages and neutrophils infiltration in the lung. Geraniin significantly attenuated LPS-induced elevation of MPO level. LPS-induced TNF-α, IL-6 and IL-1β production were markedly suppressed by treatment of geraniin. Furthermore, geraniin inhibited NF-κB activation in LPS-induced ALI. In addition, geraniin was found to up-regulate the expression of Nrf2 and HO-1. In conclusion, these data suggested that geraniin had therapeutic effects in LPS-induced ALI by inhibiting NF-κB and activating Nrf2 signaling pathways.

Geraniin Inhibits LPS-Induced THP-1 Macrophages Switching to M1 Phenotype via SOCS1/NF-κB Pathway

M1 macrophage polarization is proved to promote inflammation in atherosclerosis process. In this study, we evaluated the inhibitory effect of geraniin, a bioactive polyphenolic compound, on the LPS-induced switch of THP-1 macrophages to M1 phenotype, and we propose a molecular basis for its action. Flow cytometry analysis indicated that geraniin significantly inhibited LPS-induced M1 macrophage polarization. Geraniin downregulated the protein and the mRNA level of typical cytokines of M1 macrophage, including tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), indicating that geraniin can suppress typical mediators of M1 macrophage at the transcriptional level. Moreover, geraniin inhibited LPS-induced reactive oxygen species (ROS) and nitric oxide (NO) production, as well as inducible nitric oxide synthase (iNOS) activity, in THP-1 macrophages. Furthermore, western blot analysis indicated that geraniin decreased both LPS-induced phosphorylation of NF-κB-p65 and NF-κB-p65 expression without affecting the level of IκB-α. This suggested that geraniin inhibited NF-κB, a transcription factor pivotal in the LPS-induced expression of pro-inflammatory genes and an important player in M1 macrophage polarization. Moreover, an electrophoretic mobility shift assay (EMSA) demonstrated that geraniin blocked the LPS-induced translocation of NF-κB to the nucleus. Moreover, we found that geraniin up-regulated the expression of SOCS1, an upstream regulator of NF-κB activation that can directly bind to NF-κB-p65 and downregulate it, thus inhibiting NF-κB activation. In conclusion, geraniin inhibits LPS-induced THP-1 macrophages switching to M1 phenotype through SOCS1/NF-κB pathway.

Cytoprotective effect of chlorogenic acid against hydrogen peroxide-induced oxidative stress in MC3T3-E1 cells through PI3K/Akt-mediated Nrf2/HO-1 signaling pathway

Osteoporosis is a disorder of bone and its development is closely associated with oxidative stress and reactive oxygen species (ROS). Chlorogenic acid (CGA) has potential antioxidant effects and its pharmacological action in osteoblasts is not clearly understood. The present study aimed to clarify the protective effects and mechanisms of CGA on hydrogen peroxide (H2O2)-induced oxidative stress in osteoblast cells. MC3T3-E1 cells were treated with H2O2 to induce oxidative stress model in vitro. Cells were treated with CGA prior to H2O2 exposure, the intracellular ROS production, malondialdehyde content, nitric oxide release and glutathione level were measured. We also investigated the protein levels of heme oxygenase-1 (HO-1), the nuclear translocation of transcription factor NF-erythroid 2-related factor (Nrf2) and the phosphorylation levels of Akt in CGA-treated cells. The results showed that pretreatment of CGA could reverse the inhibition of cell viability and suppress the induced apoptosis and caspase-3 activity. Additionally, it significantly reduced H2O2-induced oxidative damage in a dose-dependent manner. Furthermore, it induced the protein expression of HO-1 together with its upstream mediator Nrf2, and activated the phosphorylation of Akt in MC3T3-E1 cells. LY294002, a PI3K/Akt inhibitor, significantly suppressed the CGA-induced Nrf2 nuclear translocation and HO-1 expression. Reduction of cell death mediated by CGA in presence of H2O2 was significantly inhibited by Zinc protoporphyrin IX (a HO-1 inhibitor) and LY294002. These data demonstrated that CGA protected MC3T3-E1 cells against oxidative damage via PI3K/Akt-mediated activation of Nrf2/HO-1 pathway, which may be an effective drug in treatment of osteoporosis.