Cytotoxic triterpenes from the acid hydrolyzate of Gynostemma pentaphyllum saponins.

One new dammarane-type triterpene, gypsapogenin A (1), was isolated from the acid hydrolyzate of total saponins from Gynostemma pentaphyllum (Thunb.) Makino, together with two known compounds, (20S,24S)-3ß,20,21ß,23ß,25-pentahydroxy-21,24-cyclodammarane (2) and (23S)-3ß-hydroxydammar-20,24-dien-21-oic acid 21,23-lactone (3). Its structural elucidations were accomplished mainly on the basis of the interpretation of spectroscopic data, such as IR, HR-TOF-MS, and NMR. The cytotoxic activities were evaluated against HepG2 and A549 human cancer cell lines.

Epigallocatechin-3-gallate attenuates acrylamide-induced apoptosis and astrogliosis in rat cerebral cortex.

The potent neurotoxic agent acrylamide (ACR) is formed during Maillard reaction in food processing. Epigallocatechin-3-gallate (EGCG), a major bioactive component of green tea, is an antioxidant, but its effects on ACR-induced neurotoxicity are unclear. Here, we investigated the neuroprotective effects of EGCG against ACR-induced apoptosis and astrogliosis in the cerebral cortex. Rats were pretreated with EGCG for 4 d and then co-administered ACR for 14 d. Immunohistochemical analysis of glial fibrillary acidic protein and 8-hydroxy-2'-deoxyguanosine indicated that EGCG attenuated astrogliosis and DNA damage in ACR-treated rats. Analysis of DNA fragmentation and protein expression of Bax, Bcl-2, caspase 3, and cytochrome c revealed that EGCG inhibited ACR-induced apoptosis. Furthermore, EGCG inhibited oxidative stress by enhancing the activity of antioxidant enzymes and glutathione levels and reducing the formation of reactive oxygen species and lipid peroxidation. Taken together, our data demonstrate that EGCG inhibits ACR-induced apoptosis and astrogliosis in the cerebral cortex.

Antibacterial Activity of Juglone against Staphylococcus aureus: From Apparent to Proteomic.

The proportion of foodborne disease caused by pathogenic microorganisms is rising worldwide, with staphylococcal food poisoning being one of the main causes of this increase. Juglone is a plant-derived 1,4-naphthoquinone with confirmed antibacterial and antitumor activities. However, the specific mechanism underlying its antibacterial activity against Staphylococcus aureus remains unclear. To elucidate the mechanism underlying its antibacterial activity, isobaric tags for relative and absolute quantitation methods of quantitative proteomics were applied for analysis of the 53 proteins that were differentially expressed after treatment with juglone. Combined with verification experiments, such as detection of changes in DNA and RNA content and quantification of oxidative damage, our results suggested that juglone effectively increased the protein expression of oxidoreductase and created a peroxidative environment within the cell, significantly reducing cell wall formation and increasing membrane permeability. We hypothesize that juglone binds to DNA and reduces DNA transcription and replication directly. This is the first study to adopt a proteomic approach to investigate the antibacterial mechanism of juglone.

Betanin attenuates carbon tetrachloride (CCl4)-induced liver injury in common carp (Cyprinus carpio L.).

This study investigates the protective effect of betanin against liver injury induced by carbon tetrachloride (CCl4) in common carp (Cyprinus carpio L.). The fish were treated with 1, 2, and 4 % betanin in fodder throughout the experiment. After 20 days of treatment, the fish were intraperitoneally injected with 20 % (v/v in peanut oil) CCl4 at a volume of 0.5 mL/kg body weight. The fish were killed 3 days after CCl4 intoxication, and then, histological and biochemical assays were performed. Results showed that CCl4-induced liver CYP2E1 activity, oxidative stress, and injury, as indicated by the depleted glycogen storage, increased serum aspartate aminotransferase (AST)/alanine aminotransferase (ALT) activities and liver histological damage. Compared with the CCl4 control group, the betanin-treated groups exhibited reduced CYP2E1 activity, decreased malondialdehyde level, increased liver antioxidative capacity (increased glutathione level and superoxide dismutase and catalase activities), increased liver glycogen storage, and reduced serum AST/ALT activities, with significant differences in the 2 and 4 % groups (p < 0.05). Histological assay further confirmed the protective effect of betanin. In conclusion, betanin attenuates CCl4-induced liver damage in common carp. Moreover, the inhibition of CYP2E1 activity and oxidative stress may have significant roles in the protective effect of betanin.

Detrimental effects of metronidazole on selected innate immunological indicators in common carp (Cyprinus carpio L.).

The widely used antibiotic metronidazole (MTZ) was investigated for its toxic effects on the innate immunity in common carp (Cyprinus carpio L.). The fish were exposed to MTZ at nominal concentrations of 0.1, 0.5, and 2.5 mg L(-1) in water for 30 days, followed by a 5-days of cleanout period, after which certain innate immunity parameters were measured. The results showed that under the tested concentrations, MTZ-exposed fish exhibited decline in several humoral and cellular parameters, including complement activity, lysozyme activity, bactericidal activity, total serum protein levels, total WBC count, and the respiratory burst activity of kidney leukocytes. Except for total serum proteins, all of these parameters showed a significant difference in the 2.5 mg L(-1) MTZ group compared to control group (p < 0.05). The results clearly support the contention that MTZ suppresses the innate immunity of common carp.

Review on toxicology and activity of tomato glycoalkaloids in immature tomatoes.

Owing to the lack of selection and limited intelligence in mechanical picking, some immature tomatoes that contain alkaloids are thrown away. Tomatine alkaloids are steroidal alkaloids naturally present in Solanaceae plants, which are distributed in small amounts in immature tomato fruits and decrease as the fruits ripen. Tomato glycoalkaloids are harmful to human health. However, in small quantities, there is some evidence that these compounds might be beneficial, as other non-antioxidant bioactivities. This article considers recent research on the biological effects of tomato glycoalkaloids in immature tomatoes, providing reference value for the potential development of these compounds.

In situ formed scaffold with royal jelly-derived extracellular vesicles for wound healing.

Background: Safe and effective wound healing can be a major clinical challenge. Inflammation and vascular impairment are two main causes of inadequate wound healing. Methods: Here, we developed a versatile hydrogel wound dressing, comprising a straightforward physical mixture of royal jelly-derived extracellular vesicles (RJ-EVs) and methacrylic anhydride modified sericin (SerMA), to accelerate wound healing by inhibiting inflammation and promoting vascular reparation. Results: The RJ-EVs showed satisfactory anti-inflammatory and antioxidant effects, and significantly promoted L929 cell proliferation and migration in vitro. Meanwhile, the photocrosslinked SerMA hydrogel with its porous interior structure and high fluidity made it a good candidate for wound dressing. The RJ-EVs can be gradually released from the SerMA hydrogel at the wound site, ensuring the restorative effect of RJ-EVs. In a full-thickness skin defect model, the SerMA/RJ-EVs hydrogel dressing accelerated wound healing with a healing rate of 96.8% by improving cell proliferation and angiogenesis. The RNA sequencing results further revealed that the SerMA/RJ-EVs hydrogel dressing was involved in inflammatory damage repair-related pathways including recombinational repair, epidermis development, and Wnt signaling. Conclusion: This SerMA/RJ-EVs hydrogel dressing offers a simple, safe and robust strategy for modulating inflammation and vascular impairment for accelerated wound healing.

S-desulfurization: A different covalent modification mechanism from persulfidation by GSH.

Post-translational transformation of cysteine residues to persulfides, known as protein S-sulfhydration or persulfidation, is a beneficial H2S signaling mechanism. In this paper, we found that GSH is bound to active cysteine sites of protein by S-desulfurization, which is a new covalent modification mechanism of protein, thus regulating catalytic activity. Here, we provide direct evidence that GSH modifies the reactive cysteine residues of four enzymes (alliinase/D-LDH/ADH/G6PD) and generates protein-SG or protein-SSG derivatives by S-desulfurization. S-desulfurization, α-carbon nucleophilic substitution or thiol-disulfide exchange occurs and H2S is released as a by-product. S-desulfurization is the opposite of persulfidation in terms of H2S production/consumption and enzyme inhibition/mitigation. Here, we elucidated the GSH mechanisms and H2S mechanisms in the enzyme-metabolite system and the beneficial roles of persulfidation and S-desulfurization. These theoretical findings are now shedding light on understanding GSH and H2S molecular functions and providing new theoretical basis for them in cell signaling pathways.

Current progress on the mechanisms of hyperhomocysteinemia-induced vascular injury and use of natural polyphenol compounds.

Cardiovascular disease is one of the most common diseases in the elderly population, and its incidence has rapidly increased with the prolongation of life expectancy. Hyperhomocysteinemia is an independent risk factor for various cardiovascular diseases, including atherosclerosis, and damage to vascular function plays an initial role in its pathogenesis. This review presents the latest knowledge on the mechanisms of vascular injury caused by hyperhomocysteinemia, including oxidative stress, endoplasmic reticulum stress, protein N-homocysteinization, and epigenetic modification, and discusses the therapeutic targets of natural polyphenols. Studies have shown that natural polyphenols in plants can reduce homocysteine levels and regulate DNA methylation by acting on oxidative stress and endoplasmic reticulum stress-related signaling pathways, thus improving hyperhomocysteinemia-induced vascular injury. Natural polyphenols obtained via daily diet are safer and have more practical significance in the prevention and treatment of chronic diseases than traditional drugs.

LncRNA CRNDE Promotes ATG4B-Mediated Autophagy and Alleviates the Sensitivity of Sorafenib in Hepatocellular Carcinoma Cells.

Autophagy is closely related to the growth and drug resistance of cancer cells, and autophagy related 4B (ATG4B) performs a crucial role in the process of autophagy. The long non-coding RNA (lncRNA) colorectal neoplasia differentially expressed (CRNDE) promotes the progression of hepatocellular carcinoma (HCC), but it is unclear whether the tumor-promoting effect of CRNDE is associated with the regulation of ATG4B and autophagy. Herein, we for the first time demonstrated that CRNDE triggered autophagy via upregulating ATG4B in HCC cells. Mechanistically, CRNDE enhanced the stability of ATG4B mRNA by sequestrating miR-543, leading to the elevation of ATG4B and autophagy in HCC cells. Moreover, sorafenib induced CRNDE and ATG4B as well as autophagy in HCC cells. Knockdown of CRNDE sensitized HCC cells to sorafenib in vitro and in vivo. Collectively, these results reveal that CRNDE drives ATG4B-mediated autophagy, which attenuates the sensitivity of sorafenib in HCC cells, suggesting that the pathway CRNDE/ATG4B/autophagy may be a novel target to develop sensitizing measures of sorafenib in HCC treatment.

Chlorpyrifos induces delayed cytotoxicity after withdrawal in primary hippocampal neurons through extracellular signal-regulated kinase inhibition.

In this study, the delayed effect and related mechanism after chlorpyrifos (CPF) withdrawal was studied in primary rat hippocampal neurons. The results showed that 10 muM CPF induced no detectable cytotoxicity during 96 h continuous exposure while its withdrawal after 48 h exposure induced evident cytotoxicity, as indexed by decreased methyl thiazolyl tetrazolium (MTT) metabolism, increased loss of neurons immunostained by neuron-specific enolase (NSE) antibody, and the increased terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) positive cell rate in the following 24 h and 48 h incubation in the absence of CPF. Extracellular signal-related kinase (ERK)1/2 activation by phosphorylation was observed and persisted during CPF exposure. However, CPF withdrawal after 48 h exposure led to inhibition of ERK1/2 phosphorylation. Carbacol and nerve growth factor (NGF), which are ERK1/2 activators, protected the neurons after CPF withdrawal, while atropine and PD98059, which are ERK1/2 inhibitors, exacerbated the cytotoxicity, indicating the involvement of inhibition of ERK1/2 phosphorylation in CPF-induced delayed cytotoxicity. In conclusion, CPF withdrawal after exposure induced delayed cytotoxicity in cultured neurons. Inhibition of ERK1/2 phosphorylation was found to be related to the delayed cytotoxicity. This finding may provide a new insight into the toxicological mechanism of organophosphorus pesticides, especially chronic organophosphate-induced neuropsychiatric disorder characterized by delayed occurrence.

Chronic organophosphate (OP)-induced neuropsychiatric disorder is a withdrawal syndrome.

Chronic organophosphate-induced neuropsychiatric disorder is a less well-characterized syndrome, which is usually delay-occurred, persists long and is similar to the symptom of cholinergic deficit, its mechanism is unclear. The characteristics of chronic organophosphate-induced neuropsychiatric disorder are somewhat opposite to the direct action of OP pesticide, since withdrawal effect is usually opposite to the original effect of a drug, hypothesis that chronic organophosphate-induced neuropsychiatric disorder is a kind of withdrawal syndrome is suggested.

Combined effects of repeated administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin and polychlorinated biphenyls on kidneys of male rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls (PCBs) are persistent environmental contaminants that exist as complex mixtures in the environment, but the possible interactions of TCDD and PCBs have not been systematically investigated. The main objective of this study was to investigate the combined nephrotoxic effects of TCDD and PCBs on rats and to reveal the potential interactions between TCDD and PCBs. Male Sprague-Dawley rats were intragastrically administered TCDD (10 microg/kg), PCBs (Aroclor 1254, 10 mg/kg), or the combination (10 microg/kg TCDD + 10 mg/kg Aroclor 1254). After 12 consecutive days of exposure, all treatments induced nephrotoxicity, as evidenced by significant increases in the levels of serum creatinine and blood urea nitrogen, changes of kidney histopathology, and significant renal oxidative stress. Most of these effects were more remarkable in the combined-exposure group. Furthermore, all treatments induced renal cytochrome P450 1A1 (CYP1A1) protein expression, and the induction was more conspicuous in the combined-exposure group. These findings suggested that the nephrotoxicity induced by TCDD and PCBs in the present study might be attributable to the high expression of CYP1A1. In addition, the result of the two-way analysis of variance revealed that the combined effects of TCDD and PCBs were complicated, being additive, synergistic, or antagonistic depending on the selection of toxicity end points under the present experimental condition. This study demonstrates that combined exposure to TCDD and PCBs induced significant nephrotoxicity in rats, and there were complicated interactions between the two pollutants on the nephrotoxicity.

Pathological Pattern of Intrahepatic HBV in HCC is Phenocopied by PDX-Derived Mice: a Novel Model for Antiviral Treatment.

BACKGROUND: Hepatitis B virus (HBV) is one of the most prominent risk factors for hepatocellular carcinoma (HCC) development and virus-mediated cases represents more than 80% of HCC in East Asia, where it is endemic. Currently, the HBV status of pathological HCC is not fully clarified, especially by comparison to nontumorous tissues. Lack of clinicopathological animal models of HCC impedes clinical application of antiviral treatment in the field. MATERIALS AND METHODS: A cohort sample of 14 HCC and corresponding stroma tissues were analyzed for pathological patterns of HBV antigens using immunohistochemistry; 10 fresh primary tumor tissues were inoculated into NOD/SCID mice and risk factors for patient-derived xenograft (PDX) model were identified by the univariate F test. Consistency of HBV features and cellular biomarkers between patient tissues and tumor grafts were examined. RESULTS: In HCC, HBV surface antigen (HBsAg) was mainly absent. Only 9.9% of samples showed HBsAg positivity in the tumor tissue that was limited to benign hepatocytes. In contrast, HBV core antigen (HBcAg) exhibited positive staining in all HCC tissues, located mainly in the cytoplasm of tumor cells. Of 14 HCC cases, three were diagnosed as occult infection of HBV based on HBcAg expression. The successful rate for the PDX model was 20% (2/10). Tumor lesions on hepatic lobes of V and VI, severe liver dysfunction and higher CA125 showed p-values of 0.01, 0.035, and 0.01, respectively. HBsAg absence in original tumors of #6 and 8 patients were faithfully reproduced by engraftments. Mixed distribution of HBcAg in cellular compartments of original tumor cells was also observed in mice. ki67 was dramatically increased in tumor grafts. CONCLUSION: We delineated pathological HBV profiles of HCC specimens and perilesional areas, which provided evidence for virus-based therapy in the future. PDX mice may phenocopy virological and cellular features of patient tissues, which is novel in the virus-related hepatocarcinogenesis field.

Melatonin Modulates lipid Metabolism in HepG2 Cells Cultured in High Concentrations of Oleic Acid: AMPK Pathway Activation may Play an Important Role.

Melatonin exists as an active ingredient in several foods and has been reported to inhibit fatty liver disease in animals; however, its molecular mechanisms are not well elucidated. Herein, we explored effects of melatonin on lipid accumulation induced by oleic acid in HepG2 cells and characterized the underlying molecular mechanisms. Pretreatment with melatonin (0.1-0.3 mM) significantly inhibited accumulation of triglyceride and cholesterol induced by incubating HepG2 cells with high concentrations of oleic acid (oleic acid overload) (p < 0.05). Melatonin pretreatment induced phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), causing their activation and inactivation, respectively. Expression levels of peroxisome proliferator activated receptor-α (PPARα) and its target gene carnitine palmitoyl-CoA transferase 1 (CPT1), which are associated with lipolysis, were upregulated by melatonin, whereas expression of sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and stearoyl-CoA desaturase-1 (SCD1), which are associated with lipogenesis, were downregulated. Melatonin did not change expression of genes involved in cholesterol metabolism, including 3-hydroxy-3-methylglutaryl CoA reductase (HMGR) and SREBP-2. Melatonin inhibits lipid accumulation induced by oleic acid overload in HepG2 cells. The phosphorylation and activation of AMPK may have important roles in inactivating lipid anabolic pathways and activating triglyceride catabolic pathways.

Epigallocatechin-3-gallate attenuates cerebral cortex damage and promotes brain regeneration in acrylamide-treated rats.

Acrylamide (ACR) is a neurotoxic industrial chemical intermediate, which is also present in food and water. We investigated the neuroprotective effects of epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, on ACR-treated rat brain. Rats were pre-treated with EGCG for 4 d and then administered ACR and EGCG for 14 d. EGCG increased acetylcholinesterase (AChE) activity and the rate of Nissl-positive cells in ACR-treated rats. Senescence-associated ß-galactosidase (SA-ß-gal) staining indicated that EGCG attenuated ACR-induced senescence. Tumour necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2) protein expression indicated that EGCG inhibited ACR-induced inflammation. In addition, immunohistochemical analysis of nestin and brain-derived neurotrophic factor (BDNF) revealed that EGCG promoted brain regeneration in ACR-treated rats. Altogether, our results suggest that EGCG can attenuate ACR-induced brain damage and promote regeneration in the cerebral cortex of rats. Therefore, we hypothesized that EGCG may alleviate ACR-related nerve injury.

Hydrogen sulfide may attenuate methylmercury-induced neurotoxicity via mitochondrial preservation.

Hydrogen sulfide (H2S) is a protective molecule and a novel gaseous mediator. Here we explored whether H2S donor (NaHS) could attenuate methylmercury (MeHg)-induced neurotoxicity in rats. The adult rats were randomly divided into four groups, i.e., control, NaHS, MeHg, and NaHS + MeHg groups. Rats of the NaHS + MeHg group were intraperitoneally (i.p) injected with 5.6 mg/kg/d of NaHS together with 5 µg/kg/d of MeHg. Rats of the MeHg group and NaHS group were injected with 5 µg/kg/d of MeHg and 5.6 mg/kg/d of NaHS, respectively. All treatments were continued for 20 d, and the cerebral cortex of the rats was evaluated. The results showed that NaHS significantly reduced MeHg-induced oxidative stress, as indicated by reduced lipid peroxide content, and increased glutathione levels and glutathione peroxidase and thioredoxin reductase activities. NaHS attenuated MeHg-induced mitochondrial damage, as indicated by increased mitochondrial activity, reduced mitochondrial swelling, and the release of cytochrome C and apoptosis-inducing factors. NaHS also decreased the number of apoptotic cells compared to that observed in MeHg only-treated rats, as indicated in a TUNEL assay. Finally, NaHS increased DNA and RNA content, and the activities of acetylcholinesterase and Na+/K+-ATPase. These indices were all lower in the MeHg group than in the control group, and NaHS alone did not observably influence any of these indices compared to the control. Our results demonstrate that H2S may protect against MeHg-induced neurotoxicity, and the mechanisms appear to involve the inhibition of oxidative stress and the protection of mitochondria.

Proteomic Analysis of the Antibacterial Mechanism of Action of Juglone against Staphylococcus aureus.

Juglone is a plant-derived 1,4-naphthoquinone with confirmed antibacterial activity. However, the mechanism of action of juglone against Staphylococcus aureus remains unclear. Possible mechanisms were explored by a proteomic analysis of S. aureus proteins that are inhibited by juglone. Two-dimensional gel electrophoresis revealed that 21 protein spots were differentially expressed between juglone-treated and untreated cells of which 13 were identified. A bioinformatic analysis revealed that proteins participating in protein synthesis, the tricarboxylic acid cycle, as well as DNA and RNA synthesis were inhibited by juglone, thus leading to cell collapse. These findings provide clues regarding the mechanism of action of juglone, which can be effective for treating cases of S. aureus infection.

Natural antioxidant betanin protects rats from paraquat-induced acute lung injury interstitial pneumonia.

The effect of betanin on a rat paraquat-induced acute lung injury (ALI) model was investigated. Paraquat was injected intraperitoneally at a single dose of 20 mg/kg body weight, and betanin (25 and 100 mg/kg/d) was orally administered 3 days before and 2 days after paraquat administration. Rats were sacrificed 24 hours after the last betanin dosage, and lung tissue and bronchoalveolar lavage fluid (BALF) were collected. In rats treated only with paraquat, extensive lung injury characteristic of ALI was observed, including histological changes, elevation of lung : body weight ratio, increased lung permeability, increased lung neutrophilia infiltration, increased malondialdehyde (MDA) and myeloperoxidase (MPO) activity, reduced superoxide dismutase (SOD) activity, reduced claudin-4 and zonula occluden-1 protein levels, increased BALF interleukin (IL-1) and tumor necrosis factor (TNF)-α levels, reduced BALF IL-10 levels, and increased lung nuclear factor kappa (NF-κB) activity. In rats treated with betanin, paraquat-induced ALI was attenuated in a dose-dependent manner. In conclusion, our results indicate that betanin attenuates paraquat-induced ALI possibly via antioxidant and anti-inflammatory mechanisms. Thus, the potential for using betanin as an auxilliary therapy for ALI should be explored further.

Betanin reduces the accumulation and cross-links of collagen in high-fructose-fed rat heart through inhibiting non-enzymatic glycation.

We attempted to determine whether betanin (from natural pigments) that has antioxidant properties would be protective against fructose-induced diabetic cardiac fibrosis in Sprague-Dawley rats. Fructose water solution (30%) was accessed freely, and betanin (25 and 100 mg/kg/d) was administered by intra-gastric gavage continuously for 60 d. Rats were sacrificed after overnight fast. The rat blood and left ventricle were collected. In vitro antiglycation assay in bovine serum albumin/fructose system was also performed. In rats treated only with fructose, levels of plasma markers: glucose, insulin, HOMA and glycated hemoglobin rised, left ventricle collagen accumulated and cross-linked, profibrotic factor-transforming growth factor (TGF)-ß1 and connective tissue growth factor (CTGF) protein expression increased, and soluble collagen decreased, compared with those in normal rats, showing fructose induces diabetic cardiac fibrosis. Treatment with betanin antagonized the changes of these parameters, demonstrating the antifibrotic role of betanin in the selected diabetic models. In further mechanistic study, betanin decreased protein glycation indicated by the decreased levels of protein glycation reactive intermediate (methylglyoxal), advanced glycation end product (N(ε)-(carboxymethyl) lysine) and receptors for advanced glycation end products (AGEs), antagonized oxidative stress and nuclear factor-κB activation elicited by fructose feeding, suggesting inhibition of glycation, oxidative stress and nuclear factor-κB activation may be involved in the antifibrotic mechanisms. Betanin also showed anitglycative effect in BSA/fructose system, which supported that anitglycation was involved in betanin's protective roles in vivo. Taken together, the potential for using betanin as an auxillary therapy for diabetic cardiomyopathy deserves to be explored further.