In vitro assessment of hepatoprotective agents against damage induced by acetaminophen and CCl4

Hepatoprotective effect of date fruit extract against ethanol-induced apoptosis in human hepatoma (HepG2) cells

Ethanol is a well-known hepatotoxic agent and date fruits have been associated with their biological actions. In current study, we have investigated the hepatoprotective potential of DFE on ethanol-induced cellular damages in human hepatoma (HepG2) cells. The hepatoprotective potential was assessed by exposing the HepG2 cells to non-toxic concentrations (15, 30, and 60 μg/mL) of DFE for 24 h; then toxic concentration (500 μM) of ethanol. Our results demonstrated that pretreatment with DFE significantly prohibited ethanol-induced hepatotoxicity in HepG2 cells. We observed that DFE treatment increased cell viability, reduced LDH leakage, restored cellular morphology, and inhibited caspase-3 enzyme activity in a dose dependent way, induced by ethanol. Further DFE was also effective in restoring the LPO, GSH, and catalase levels towards normal altered by ethanol. Our results also revealed that ethanol-induced ROS generation was significantly inhibited by DFE. The ethanol-induced mRNA expression of apoptotic related genes (p53, caspase-3, caspase-7, Bax, and Bcl-2) were also normalized by pretreatment with DFE. The findings from this study indicated that DFE can significantly protect HepG2 cells against ethanol-induced hepatotoxicity. Our study also provides scientific validation for the traditional use of DFE, aiming to understand its hepatoprotective potential. Altogether, to the best of our knowledge, this is the first study demonstrated that ethanol-induced hepatotoxicity can be prohibited by the DFE. Thus, DFE has a potential application in nutraceuticals as a therapeutic agent to prevent liver diseases.

Exploring the hepatoprotective properties of citronellol: In vitro and in silico studies on ethanol-induced damage in HepG2 cells

Citronellol (CT) is a monoterpene alcohol present in the essential oil of plants of the genus Cymbopogon and exhibits diverse pharmacological activities. The aim of the current study was to investigate the hepatoprotective potential of CT against ethanol-induced toxicity in HepG2 cell lines. Silymarin (SIL) was used as a standard drug. MTT, crystal violet assay, DAPI, and PI staining were carried out to assess the effect of ethanol and CT on cell viability. RT-PCR determined the molecular mechanisms of hepatoprotective action of CT. CT ameliorated cell viability and restricted ethanol-induced cell death. DAPI and PI staining showed distinct differences in cell number and morphology. Less cell viability was observed in the diseased group obviously from strong PI staining when compared to the CT- and SIL-treated group. Moreover, CT showed downregulation of interleukin (IL-6), transforming growth factor-beta 1 (TGF-β1), collagen type 1 A 1 (COL1A1), matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and glutathione peroxidase-7 (GPX-7) levels. Molecular docking studies supported the biochemical findings. It is concluded that the cytoprotective activity of CT against ethanol-induced toxicity might be explained by its anti-inflammatory, immunomodulatory, and collagen-regulating effects.

Scutellaria Root extract-induced hepatocytotoxicity can be controlled by regulating its baicalin content

Scuellaria Root (SR, root of Scutellaria baicalensis), which has potent anti-inflammatory effects, is a component of useful Kampo formulae. Albeit a low frequency, SR induces serious interstitial pneumonia and liver dysfunction. In this study, to control the adverse effects of SR, we investigated the causal constituent responsible for its hepatocytotoxicity and aimed to develop a method to control it. As a result, we revealed that the hepatocytotoxicity of SR was correlated with its baicalin content, a major constituent in SR. It was confirmed by preparing a baicalin-free SR extract, which exhibited reduced hepatocytotoxicity. The addition of baicalin to the baicalin-free SR extract restored the hepatocytotoxicity, indicating that the hepatocytotoxicity of SR is dependent on its baicalin content. Thus, SR extract-induced hepatocytotoxicity can be controlled by regulating its baicalin content.

Cereblon deficiency ameliorates carbon tetrachloride-induced acute hepatotoxicity in HepG2 cells by suppressing MAPK-mediated apoptosis

The liver is vulnerable to various hepatotoxins, including carbon tetrachloride (CCl4), which induces oxidative stress and apoptosis by producing reactive oxygen species (ROS) and activating the mitogen-activated protein kinase (MAPK) pathway. Cereblon (CRBN), a multifunctional protein implicated in various cellular processes, functions in the pathogenesis of various diseases; however, its function in liver injury remains unknown. We established a CRBN-knockout (KO) HepG2 cell line and examined its effect on CCl4-induced hepatocellular damage. CRBN-KO cells exhibited reduced sensitivity to CCl4-induced cytotoxicity, as evidenced by decreased levels of apoptosis markers, such as cleaved caspase-3, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. CRBN deficiency enhanced antioxidant defense, with increased superoxide dismutase activity and glutathione ratios (GSH/GSSG), as well as reduced pro-inflammatory cytokine expression. Mechanistically, the protective effects of CRBN deficiency appeared to involve the attenuation of the MAPK-mediated pathways, particularly through decreased phosphorylation of JNK and ERK. Overall, these results suggest the crucial role of CRBN in mediating the hepatocellular response to oxidative stress and inflammation triggered by CCl4 exposure, offering potential clinical implications for liver injury in a wide range of liver diseases.

Robust anti-tubercular profile of Solanum virginianum extract in enhancing isoniazid bioavailability and curtailing stress tolerance in Mycobacterium smegmatis

Introduction

The formidable survival mechanisms employed by Mycobacterium tuberculosis (Mtb), combined with the low bioavailability of anti-tubercular drugs and their associated hepatotoxicity, worsen tuberculosis management. Traditional medicinal plants offer potential solutions to these challenges. This study focuses on exploring the anti-tubercular potential of Solanum virginianum against Mycobacterium smegmatis, mc2155.

Methods and results

HPTLC and UHPLC phytochemically characterized the hydro-methanolic extract of Solanum virginianum (SVE). SVE curtails the growth and viability of mc2155 under normal and in vitro stress conditions. The compromised cell wall integrity of mc2155 with SVE is depicted through scanning electron microscopy (SEM) while EtBr permeability assays and TLC-based comparative changes in lipids extraction addressed the integrity of the cell wall. Furthermore, SVE augmented the susceptibility of mc2155 towards Isoniazid (INH) through enhanced bioavailability. Adjunct treatment of SVE with INH demonstrated a markedly reduced survival of the intracellular bacilli. The study also uncovered the hepatoprotective potential of SVE in HepG2 cells.

Conclusion

This research paves the way for deeper exploration into the potential of Solanum virginianum against virulent Mtb strains, emphasizing over the significance of traditional medicinal plants in tuberculosis treatment. Collectively, the findings suggest SVE as a potent candidate for independent or adjunct anti-tubercular therapy.

Silymarin enriched gelatin methacrylamide bioink imparts hepatoprotectivity to 3D bioprinted liver construct against carbon tetrachloride induced toxicity

Three-dimensional liver bioprinting is an emerging technology in the field of regenerative medicine that aids in the creation of functional tissue constructs that can be used as transplantable organ substitutes. During transplantation, the bioprinted donor liver must be protected from the oxidative stress environment created by various factors during the transplantation procedure, as well as from drug-induced damage from medications taken as part of the post-surgery medication regimen following the procedure. In this study, Silymarin, a flavonoid with the hepatoprotective properties were introduced into the GelMA bioink formulation to protect the bioprinted liver against hepatotoxicity. The concentration of silymarin to be added in GelMA was optimised, bioink properties were evaluated, and HepG2 cells were used to bioprint liver tissue. Carbon tetrachloride (CCl4) was used to induce hepatotoxicity in bioprinted liver, and the effect of this chemical on the metabolic activities of HepG2 cells was studied. The results showed that Silymarin helps with albumin synthesis and shields liver tissue from the damaging effects of CCl4. According to gene expression analysis, CCl4 treatment increased TNF-α and the antioxidant enzyme SOD expression in HepG2 cells while the presence of silymarin protected the bioprinted construct from CCl4-induced damage. Thus, the outcomes demonstrate that the addition of silymarin in GelMA formulation protects liver function in toxic environments.

Coculture model of a liver sinusoidal endothelial cell barrier and HepG2/C3a spheroids-on-chip in an advanced fluidic platform

The liver is one of the main organs involved in the metabolism of xenobiotics and a key organ in toxicity studies. Prior to accessing the hepatocytes, xenobiotics pass through the hepatic sinusoid formed by liver sinusoidal endothelial cells (LSECs). The LSECs barrier regulates the kinetics and concentrations of the xenobiotics before their metabolic processing by the hepatocytes. To mimic this physiological situation, we developed an in vitro model reproducing an LSECs barrier in coculture with a hepatocyte biochip, using a fluidic platform. This technology made dynamic coculture and tissue crosstalk possible. SK-HEP-1 and HepG2/C3a cells were used as LSECs and as hepatocyte models, respectively. We confirmed the LSECs phenotype by measuring PECAM-1 and stabilin-2 expression levels and the barrier's permeability/transport properties with various molecules. The tightness of the SK-HEP-1 barrier was enhanced in the dynamic coculture. The morphology, albumin secretion, and gene expression levels of markers of HepG2/C3a were not modified by coculture with the LSECs barrier. Using acetaminophen, a well-known hepatotoxic drug, to study tissue crosstalk, there was a reduction in the expression levels of the LSECs markers stabilin-2 and PECAM-1, and a modification of those of CLEC4M and KDR. No HepG2/C3a toxicity was observed. The metabolisation of acetaminophen by HepG2/C3a monocultures and cocultures was confirmed. Although primary cells are required to propose a fully relevant model, the present approach highlights the potential of our system for investigating xenobiotic metabolism and toxicity.

Flavonoids of Chromolaena odorata (L.) R.M.King & H.Rob. as potential leads for treatment against tuberculosis

Tuberculosis (TB) is currently rated as the 13th leading cause of mortality and the second leading cause of death after COVID-19, and above AIDS. Existing challenges relating to the development of multidrug-resistant strains and dangerous side effects of currently used drugs add impetus to the search for additional TB treatments. Hence, interest has grown in the use of medicinal plants as a source of bioactive preparations with efficacy against TB-causing organisms, and also with the ability to ameliorate the negative effects of TB drugs. This study aimed to evaluate the antimycobacterial and hepatoprotective potentials of extracts and isolated flavonoid compounds from invasive Chromolaena odorata. Test organisms used were pathogenic Mycobacterium bovis and M. tuberculosis H37RV, and the fast-growing M. aurum, M. fortuitum and M. smegmatis. The selectivity index (SI) values of the test substances were determined through cytotoxicity assays to promote these extracts and compounds as leads for the development of effective and safe anti-tubercular drugs. The antimycobacterial activity was evaluated using a serial microdilution method, and the SI was calculated from the 50% lethal concentrations calculated from cytotoxicity tests. Hepatoprotective activity was determined using HepG2 liver cells treated with rifampicin as a toxin. The extracts and compounds had a range of antimycobacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.031 to 2.5 mg/mL. Two flavonoid compounds, 5,7,4'-trimethoxy flavanone and 5‑hydroxy-3,7,4'-trimethoxyflavone showed promising antimycobacterial potential, and minimal toxicity was observed, as most SI values were higher than 1. The flavonoid compound 5,7,4'-trimethoxy flavanone had the highest SI (6.452), which was against M. tuberculosis H37RV. The HepG2 cells were reduced to 65% due to toxicity by rifampicin, however, the flavonoid compounds were able to improve cell viability to between 81 and 89% at different concentrations tested. Results obtained indicate that C. odorata may serve as a lead for the development of safe and effective antimycobacterial and hepatoprotective drugs.

Moringa oleifera Lam Leaf Extract Stimulates NRF2 and Attenuates ARV-Induced Toxicity in Human Liver Cells (HepG2)

The World Health Organization (WHO) reported that there are 37 million individuals living with the human immunodeficiency virus (HIV) worldwide, with the majority in South Africa. This chronic disease is managed by the effective use of antiretroviral (ARV) drugs. However, with prolonged use, ARV drug-induced toxicity remains a clinically complex problem. This study investigated the toxicity of ARV drugs on mitochondria and the NRF2 antioxidant pathway and its possible amelioration using Moringa oleifera Lam (MO) leaf extracts. This medicinal plant has a range of functional bioactive compounds. Liver (HepG2) cells were treated with individual ARV drugs: Tenofovir disoproxil fumarate (TDF), Emtricitabine (FTC), and Lamivudine (3TC) for 96 h, followed by MO leaf extracts for 24 h. Intracellular ROS, cytotoxicity, lipid peroxidation, total and reduced glutathione (GSH), ATP, and mitochondrial polarisation were determined. Finally, protein (pNRF2, NRF2, SOD2, CAT, and Sirt3) and mRNA (NRF2, CAT, NQO1 SOD2, Sirt3, and PGC1α) expression were measured using Western blot and qPCR, respectively. TDF, FTC, and 3TC significantly increased intracellular ROS and extracellular levels of both MDA and LDH. ARVs also reduced the GSH and ATP levels and altered the mitochondrial polarization. Further, ARVs reduced the expression of NRF2 SOD2, Sirt3, CAT, NQO1, UCP2 and PGC1α mRNA and consequently pNRF2, NRF2, SOD2, Sirt3 and CAT protein. In contrast, there was a significant reduction in the extracellular MDA and LDH levels post-MO treatment. MO significantly reduced intracellular ROS while significantly increasing GSH, ATP, and mitochondrial membrane polarization. The addition of MO to ARV-treated cells significantly upregulated the expression of NRF2, SOD2, Sirt3, CAT, UCP2, PGC1α, and NQO1 mRNA and pNRF2, NRF2, SOD2, Sirt3 proteins. Thus, MO ameliorates ARV-induced hepatotoxicity by scavenging oxidants by inducing the NRF2 antioxidant pathway. MO shows great therapeutic potential and may be considered a potential supplement to ameliorate ARV drug toxicity.

Enrichment of soy isoflavone extracts through macroporous resin for characterization of toxicity and estrogenic activities

Soy isoflavone extracts are widely researched for their distinctive potential in contributing to various functional foods. The research work focuses on testing the toxicity of purified soy isoflavone extracts in mice models. With an agreement of the animal ethics, acute toxicity is firstly used to screen the effects of test compounds in mice for therapeutic purposes. Moreover, tests were conducted on BALB/c for estrogen in vivo and MCF7 for in vitro, screening active protection of liver cells, lipid peroxidation and scavenging free radicals 2,2-diphenyl-1-picrylhydrazyl (DPPH). Genistin and daidzin were found to be the two major compounds accounting for 47% and 35% of total purified soy isoflavones. The acute toxicity test results exhibited no effect against physiological accretion of BALB/c after 7-day administration with the given dose of 10 g/kgBW. Moreover, modified E-screen assay on MCF7 cells proved that the estrogen of isoflavone extracts induces cell proliferation by 15% compared with other non-steroid culture techniques. Therefore, this research contributes to helping researchers apply soy isoflavones in functional food, to alleviate the difficulties in menopausal symptoms for women in the future.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05491-4.

Development of a Highly Potent Transthyretin Amyloidogenesis Inhibitor: Design, Synthesis, and Evaluation

Transthyretin amyloidosis (ATTR) is a group of fatal diseases described by the misfolding and amyloid deposition of transthyretin (TTR). Discovering small molecules that bind and stabilize the TTR tetramer, preventing its dissociation and subsequent aggregation, is a therapeutic strategy for these pathologies. Departing from the crystal structure of TTR in complex with tolcapone, a potent binder in clinical trials for ATTR, we combined rational design and molecular dynamics (MD) simulations to generate a series of novel halogenated kinetic stabilizers. Among them, M-23 displays one of the highest affinities for TTR described so far. The TTR/M-23 crystal structure confirmed the formation of unprecedented protein–ligand contacts, as predicted by MD simulations, leading to an enhanced tetramer stability both in vitro and in whole serum. We demonstrate that MD-assisted design of TTR ligands constitutes a new avenue for discovering molecules that, like M-23, hold the potential to become highly potent drugs to treat ATTR.

BML-257, a Small Molecule that Protects against Drug-Induced Liver Injury in Zebrafish

The use of many essential drugs is restricted due to their deleterious effects on the liver. Molecules that can prevent or protect the liver from drug-induced liver injury (DILI) would be invaluable in such situations. We used a transgenic line in zebrafish with a hepatocyte-specific expression of bacterial nitroreductase to cause temporally controlled liver damage. A whole organism-based chemical screen using the transgenic line identified BML-257, a potent small molecule AKT inhibitor, that protected the liver against metronidazole-induced liver injury. BML-257 also showed potent prophylactic and pro-regenerative activity in this liver damage model. BML-257 was tested in two independent toxicological models of liver injury caused by acetaminophen and isoniazid and was found to be protective against damage. This suggests that BML-257 has the potential to protect against multiple kinds of DILI.

Dietary phenolic-type Nrf2-activators: implications in the control of toxin-induced hepatic disorders

Numerous studies have exemplified the importance of nuclear factor erythroid 2-related factor 2 (Nrf2) activation in the alleviation of toxin-induced hepatic disorders primarily through eliminating oxidative stress. Whereafter, increasingly more efforts have been contributed to finding Nrf2-activators, especially from dietary polyphenols. The present review summarized the phenolic-type Nrf2-activators published in the past few decades, analyzed their effectiveness based on their structural characteristics and outlined their related mechanisms. It turns out that flavonoids are the largest group of phenolic-type Nrf2-activators, followed by nonflavonoids and phenolic acids. When counting on subgroups, the top three types are flavonols, flavones, and hydroxycinnamic acids, with curcuminoids having the highest effective doses. Moreover, most polyphenols work through the phosphorylation of Nrf2. Besides, mitogen-activated protein kinases (MAPKs) and protein kinase B (Akt) are the frequent targets of these Nrf2-activators, which indirectly mediate the behavior of Nrf2. However, current data are not sufficient to conclude any structure-activity relationship.

Hepatoprotective effect of Trigonella foenum graecum against ethanol-induced cell death in human liver cells (HepG2 and Huh7)

BACKGROUND

The plant Trigonella foenum graecum, also known as fenugreek, has been shown to have anticancer, antidiabetic, anti-inflammatory, and antioxidant properties. In this study, the hepatoprotective effect of fenugreek seed extract (FSE) against ethanol-induced cell death was investigated in human liver cells (HepG2 and Huh7).

METHODS AND RESULTS

The cytotoxic effect of FSE and ethanol on cells was evaluated by exposing the cells at different concentrations. Following that, the cells were pre-incubated with 5-25 μg/ml FSE, followed by a cytotoxic concentration (0.5 mM) of ethanol. MTT and neutral red uptake assays were performed in treated cells to assess the ability of FSE to protect cells from the cytotoxic effects of ethanol. When compared to controls, ethanol treatment significantly reduced the viability of HepG2 and Huh7 cells and altered the cell morphology, whereas treatment with FSE significantly increased cell viability and reversed ethanol-induced morphological changes. Furthermore, pretreatment with FSE dose-dependently reduced lactate dehydrogenate (LDH) leakage, lipid peroxidation (LPO) level, and catalase activities while increasing glutathione (GSH) level induced by ethanol. Pretreatment with FSE also reduced the generation of reactive oxygen species (ROS), caspase enzyme activities, and protein expression of caspase-3 and -9. In HepG2 cells, ethanol-induced apoptosis was observed, whereas FSE treatment reduced apoptosis by downregulating the expression of pro-apoptotic marker genes and upregulating the antiapoptotic gene.

CONCLUSIONS

In conclusion, this study reports on the mechanistic details of the hepatoprotective potential of FSE. The results also suggest that fenugreek seeds may be useful in preventing liver diseases caused by toxicants such as ethanol.

Development of a Hepatoprotective Herbal Drug from Turnera diffusa

The incidence of liver diseases, such as nonalcoholic fatty liver disease and drug-induced liver injury, continues to rise and is one of the leading causes of acute hepatitis. Current trends suggest that these types of conditions will increase in the coming years. There are few drugs available for the prevention or treatment of hepatic diseases, and there is a growing need for the development of safe hepatoprotective agents. The medicinal plant, Turnera diffusa, has many ethnopharmacological uses, one of which is the production of a flavonoid named hepatodamianol, which is the principal component responsible for this plant's hepatoprotective properties. In the present study, we describe the development and standardization of an active extract obtained from T. diffusa. We conducted nuclear magnetic resonance spectroscopy to identify hepatodamianol unambiguously in each sample. Using this extract, hepatoprotection could be demonstrated in vivo for the first time. The hepatoprotective effect did not display a significant difference in vivo when compared with silymarin used as a positive control at the same doses. Implementation of quality criteria used for standardization, such as flavonoid and hepatodamianol content, hepatoprotective activity, and absence of residual solvents, will allow future preclinical trials with this herbal drug.

Sage, Salvia officinalis L., Constituents, Hepatoprotective Activity, and Cytotoxicity Evaluations of the Essential Oils Obtained from Fresh and Differently Timed Dried Herbs: A Comparative Analysis

Sage, Salvia officinalis L., is used worldwide as an aromatic herb for culinary purposes as well as a traditional medicinal agent for various ailments. Current investigations exhibited the effects of extended dryings of the herb on the yields, composition, oil quality, and hepatoprotective as well as anti-cancer biological activities of the hydrodistillation-obtained essential oils from the aerial parts of the plant. The essential oils’ yields, compositions, and biological activities levels of the fresh and differently timed and room-temperature dried herbs differed significantly. The lowest yields of the essential oil were obtained from the fresh herbs (FH, 631 mg, 0.16%), while the highest yield was obtained from the two-week dried herbs (2WDH, 1102 mg, 0.28%). A notable decrease in monoterpenes, with increment in the sesquiterpene constituents, was observed for the FH-based essential oil as compared to all the other batches of the essential oils obtained from the different-timed dried herbs. Additionally, characteristic chemotypic constituents of sage, i.e., α-pinene, camphene, β-pinene, myrcene, 1, 8-cineole, α-thujone, and camphor, were present in significantly higher proportions in all the dried herbs’ essential oils as compared to the FH-based essential oil. The in vivo hepatoprotective activity demonstrated significant reductions in the levels of AST, ALT, and ALP, as well as a significant increase in the total protein (p < 0.05) contents level, as compared to the acetaminophen (AAP) administered experimental group of rats. A significant reduction (p < 0.05) in the ALT level was demonstrated by the 4WDH-based essential oil in comparison to the FH-based essential oil. The levels of creatinine, cholesterol, and triglycerides were reduced (p < 0.05) in the pre-treated rats by the essential oil batches, with non-significant differences found among them as a result of the herbs dryings based oils. A notable increase in the viability of the cells, and total antioxidant capacity (TAOxC) levels, together with the reduction in malondialdehyde (MDA) levels were observed by the essential oils obtained from all the batches as compared with the AAP-treated cell-lines, HepG-2, HeLa, and MCF-7, that indicated the in vitro hepatoprotective effects of the sage essential oils. However, significant improvements in the in vivo and in vitro hepatoprotective activities with the 4WDH-based oil, as compared to all other essential oil-batches and silymarin standard demonstrated the beneficial effects of the drying protocol for the herb for its medicinal purposes.

The Performance of HepG2 and HepaRG Systems through the Glass of Acetaminophen-Induced Toxicity

Investigation of drug-induced liver injuries requires appropriate in vivo and in vitro toxicological model systems. In our study, an attempt was made to compare the hepatocarcinoma HepG2 and the stem cell-derived HepaRG cell lines both in two- and three-dimensional culture conditions to find the most suitable model. Comparison of the liver-specific characteristics of these models was performed via the extent and mechanism of acetaminophen (APAP)-induced hepatotoxicity. Investigating the detailed mechanism of APAP-induced hepatotoxicity, different specific cell death inhibitors were used: the pan-caspase inhibitor zVAD-fmk and dabrafenib significantly protected both cell lines from APAP-induced cell death. However, the known specific inhibitors of necroptosis (necrostatin-1 and MDIVI) were only effective in differentiated HepaRG, which suggest a differential execution of activated pathways in the two models. By applying 3D culture methods, CYP2E1 mRNA levels could be elevated, but we failed to achieve a significant increase in hepatocyte function; hence, the 3D cultivation especially in APAP toxicity studies is not necessarily worth the complicated maintenance. Based on our findings, the hepatocyte functions of HepaRG may stand between the properties of HepG2 cells and primary hepatocytes (PHHs). However, it should be noted that in contrast to PHHs having many limitations, HepaRG cells are relatively immortal, having a stable phenotype and CYP450 expression.

Tricoumaroylspermidine from rose exhibits inhibitory activity against ethanol-induced apoptosis in HepG2 cells

Hepatocyte apoptosis is involved in the pathogenesis of alcohol-associated liver disease (ALD) and anti-apoptotic agents/extracts are thereby of great importance in the prevention/treatment of ALD. In this study, the protective effects of 10 edible flowers against ethanol-induced cell death were investigated in HepG2 cells, with rose (Rosa rugosa) showing the strongest activity. Therefore, rose was chosen for further separation and purification of bioactive fractions. A special fraction, SLs, was found to significantly increase the viability of EtOH-treated cells and attenuated EtOH-induced apoptosis partially via the activation of the AMPK/SIRT1 signaling pathway. Chromatographic analysis identified a series of hydroxycinnamic acid amides, kaempferol glycosides, and quercetin glycosides in this fraction, while the following intracellular uptake and cytotoxicity studies revealed that N1,N5,N10-(E)-tri-p-coumaroylspermidine (a hydroxycinnamic acid amide) in this fraction exhibited remarkable hepatoprotective activity with similar effective dosage to sulforaphane. Hence, our results highlighted the anti-alcohol and hepatoprotective benefits of consuming rose.

Selenoprotein V protects against endoplasmic reticulum stress and oxidative injury induced by pro-oxidants

Selenoprotein V (SELENOV) contains a thioredoxin-like fold and a conserved CxxU motif with a potential redox function. This study was to assess its in vivo and in vitro roles and mechanisms in coping with different oxidant insults. In Experiment (Expt.)1, SELENOV knockout (KO) and wild type (WT) mice (male, 8-wk old) were given an ip injection of saline, diquat (DQ, 12.5 mg/kg), or N-acetyl-para-aminophenol (APAP, 300 mg/kg) (n = 10), and killed 5 h after the injection. In Expt. 2, primary hepatocytes of WT and KO were treated with DQ (0-0.75 mM) or APAP (0-6 mM) for 12 h. In Expt. 3, 293 T cells overexpressing Selenov gene (OE) were treated with APAP (0-4 mM) for 24 h or H₂O₂ (0-0.4 mM) for 12 h. Compared with the WT, the DQ- and APAP-injected KO mice had higher (P < 0.05) serum alanine aminotransferase activities and hepatic malondialdehyde (MDA), protein carbonyl, endoplasmic reticulum (ER) stress-related proteins (BIP and CHOP), apoptosis-related proteins (FAK and caspase-9), and 3-nitrotyrosine, along with lower total anti-oxidizing-capability (T-AOC) and severer hepatic necrosis. Likewise, the DQ and APAP-treated KO hepatocytes had elevated (P < 0.05) cell death (10-40%), decreased (P < 0.05) T-AOC (63-83%), glutathione (26-87%), superoxide dismutase (SOD) activity (28-36%), mRNA levels of redox enzymes (Cat, Gcs, Gpx3, and Sod) and (or) sharper declines (P < 0.05) in cellular respiration and ATP production than that of the WT cells. In contrast, the OE cells had greater viability and T-AOC and lower MDA, and carbonyl contents after the APAP and H₂O₂ exposures (all at P < 0.05) than the controls. Moreover, the OE cells had greater (P < 0.05) redox enzyme activities (GPX, TrxR, and SOD), and lower (P < 0.05) expressions of ER stress-related genes (Atf4, Atf6, Bip, Xbp1t, Xbp1s, and Chop) and proteins (BIP, CHOP, FAK, and caspase-9) than the control cells after the treatment of H₂O₂ (0.4 mM). In conclusion, SELENOV conferred protections in vivo and in vitro against the reactive oxygen and nitrogen species-mediated ER stress-related signaling and oxidative injuries.

Antioxidant and Hepatoprotective Activity of Phenyl Glycosides Isolated From Heliciopsis lobata

A new macrocyclic glycoside named helilobatoside A (1) and 5 known phenyl glycosides as 3,5-dimethoxy-4-hydroxyphenyl-1- O-β-d-glucopyranoside (2), tachioside (3), isotachioside (4), 1-(4-hydroxy-3-methoxyphenyl)-1-propanone-3- O-β-d-glucopyranoside (5), and 1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone-3- O-β-d-glucopyranoside (6), were isolated from the wood of Heliciopsis lobata (Merr.) Sleumer. Their chemical structures were elucidated using a combination of high-resolution electrospray ionization mass spectrometry, 1-dimensional (1D) and 2D nuclear magnetic resonance (NMR) spectral data as well as by comparison with data in the previous literature. This is the first time the 13C NMR data of compounds 5 and 6 were reported and also were assigned by heteronuclear single quantum correlation and heteronuclear multiple bond correlation spectra. Compounds 2-6 were first isolated from Heliciopsis genus. The isolated compounds were evaluated for their antioxidant and hepatoprotective activities in vitro. Compound 2 showed potential as an antioxidant in a 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay (half-maximal inhibitory concentration [IC50] = 6.07 ± 0.17 µg/mL) and in thio-barbituric acid reactive substances assay (IC50 = 89.55 ± 8.26 µg/mL). This compound could also reduce the toxic effects of carbon tetrachloride on HepG2 survival and significantly protect the viability of cells up to 52.25 ± 4.36% at the 100 µg/mL treatment ( P < 0.05). Thus, with obtained results, the hepatoprotective activity of compound 2 could be related to radical scavenging and limited the lipid peroxidative activities.

Hepatoprotection of Mentha aquatica L., Lavandula dentata L. and Leonurus cardiaca L

The phenolic composition of hydroethanolic extracts of Mentha aquatica L., Lavandula dentata L. and Leonurus cardiaca L., obtained from plants grown under organic cultivation, was determined and their hepatoprotective effects were investigated in vitro. L. cardiaca extract was rich in phenylethenoid glycosides, especially lavandolifolioside (254 ± 36 μg/mg), whereas rosmarinic acid and eriodictyol-O-rutinoside were the major phenolic compounds of L. dentata and M. aquatica extracts, accounting for 68 ± 7 μg/mg and 145 ± 22 μg/mg, respectively. These differential phenolic components presumably account for their dissimilar antioxidant properties. While L. cardiaca extract showed moderate biological effects, M. aquatica extract displayed high antioxidant activity in chemical models, and that of L. dentata was effective in counteracting potassium dichromate-induced ROS generation in human hepatocarcinoma cells. Moreover, M. aquatica extract (50 μg/mL) and its mixture (50%/50%) with L. dentata extract displayed an effective cytoprotective effect.

Hepatoprotective effects of phosphatidylserine liposomes on carbon tetrachloride-induced hepatotoxicity in rats

It has been proposed carbon tetrachloride (CCl₄ ) intoxication due to the production of free radicals and serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) overload results hepatotoxicity. Phosphatidylserine (PS) has shown antioxidant activity in numerous studies. Therefore, this study was aimed to investigate the effects of PS liposomes treatment against the CCl₄ -induced hepatotoxicity in a rat model. Male Wistar rats were treated with PS (10 mg/kg, oral) or phosphatidylcholine liposomes (PC) (10 mg/kg, oral) for 3 days before CCl₄ (2 ml/kg; ip once on the third day) injection. The serum level of ALT, AST, and ALP were measured. Also, antioxidant assays were performed. Administration of PS with CCl₄ significantly inhibited alterations in the serum levels of AST, ALP (^** P < 0.01), and ALT (^*** P < 0.001) compared with control group. Furthermore, measurement of malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) levels indicated that PS significantly reduced reactive oxygen species. The results of the present study showed the hepatoprotective effects of PS against CCl₄ -induced hepatotoxicity in rats.

Repression of Acetaminophen-Induced Hepatotoxicity in HepG2 Cells by Polyphenolic Compounds from Lauridia tetragona (L.f.) R.H. Archer

Lauridia tetragona (L.f) R.H. Archer is routinely used in traditional medicine; however, its hepatoprotective property is yet to be scientifically proven. To this effect, the hepatoprotective activity of the polyphenolic-rich fractions (PPRFs) was investigated against acetaminophen (APAP) injured HepG2 cells. The ability of the PPRF to scavenge free radicals was tested against 2,2-diphenyl-1-picrylhydrazyl (DPPH), and [2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonicacid)] (ABTS). The ferric ion reducing power (FRAP) was also evaluated as a cell-free antioxidant assay. The hepatoprotective activity was then investigated by observing the effect of PPRFs against APAP-induced reduction in cell viability of HepG2 cells. The concentrations of alanine aminotransferase (AST), aspartate aminotransferase (ALT) and lactate dehydrogenase (LDH) released into the medium were evaluated while the underlying mechanism was further explored through western blot analysis. Thereafter, the isolated PPRFs were identified using UHPLC-QToF-MS. All six fractions of the PPRFs isolated showed significant antioxidant properties that were evident by the effective scavenging of DPPH, ABTS, and higher FRAP. The results indicated that PPRF pretreatments ameliorated APAP-induced hepatocellular injury by significantly inhibiting the leakage of AST, ALT, and LDH into the medium. The most active fractions for hepatoprotection were PPRF4 and PPRF6 with IC₅₀ of 50.243 ± 8.03 and 154.59 ± 1.9 μg/mL, respectively. PPRFs markedly increased activities of liver superoxide dismutase, total antioxidant capacity, and liver glutathione concentration. Both PPRF4 and PPRF6 significantly increased the expression of Nrf2 and translocation. The LC-MS analysis revealed the presence of a wide variety of polyphenolics such as coumarin, ferulic acid, and caffeine among the dominant constituents. In conclusion, this study demonstrates that the isolated PPRFs have potential hepatoprotective activity that may be due to the increased expression of antioxidative genes dependent on Nrf2.

SVIP alleviates CCl4-induced liver fibrosis via activating autophagy and protecting hepatocytes

Prolonged parenchymal cell death leads to activation of fibrogenic cells and extracellular matrix accumulation and eventually liver fibrosis. Autophagy, a major catabolic process of intracellular degradation and recycling, participates in hepatic fibrosis. However, the precise role of autophagy in the pathogenesis of hepatic fibrosis is controversial. The present study aims to investigate the key role of small VCP/p97 interacting protein (SVIP) against CCl₄-induced hepatic fibrosis via activating autophagy. Autophagy could be activated by SVIP in HepG2 cells, but starvation cannot increase SVIP expression in vitro and in vivo. Moreover, SVIP expression, in agreement with autophagic activity and the volume of lipid droplets, first increases and then decreases during the progression of liver fibrosis with CCl₄ treatment in vivo and in vivo. Further, overexpression of SVIP can protect HepG2 cells from the toxicity of CCl₄, which could be enhanced by starvation. Finally, starvation keeps SVIP and autophagy at such high levels in the rat livers that markedly delays the progress of hepatic fibrosis. Probably, the protective effect of SVIP is associated with stabilizing nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2) and transcription factor EB (TFEB). The current study provides insight into the biological role of SVIP and autophagy in regulating hepatic fibrosis, targeting SVIP might be a novel therapeutic strategy in the future.

Comparison of microRNA expressions for the identification of chemical hazards in in vivo and in vitro hepatic injury models

Biofluid-based biomarkers provide an efficient tool for hazard identification of chemicals. Here, we explored the potential of microRNAs (miRNAs) as biomarkers for hepatotoxicity of chemicals by linking in vitro to in vivo animal models. A search of the literature identified candidate circulating miRNA biomarkers of chemical-induced hepatotoxicity. The expression of candidate miRNAs (miR-122, miR-151a, miR-192, miR-193a, miR-194, miR-21, miR-29c), was determined by real-time reverse transcription-polymerase chain reaction in in vivo acute liver injury induced by acetaminophen, and then were further compared with those of in vitro cell assays. Candidate miRNAs, except miR-29c, were significantly or biologically upregulated by acetaminophen, at a dose that caused acute liver injury as confirmed by hepatocellular necrosis. Except miR-122 and miR-193a, other miRNAs elevated in in vivo models were confirmed by in vitro models using HepG2 cells, whereas they failed by in vitro models using human primary hepatocytes. These findings indicate that certain miRNAs may still have the potential of toxicological biomarkers in linking in vitro to in vivo hepatotoxicity.

The hydroethanolic Litchi chinensis leaf extract alleviate hepatic injury induced by carbon tetrachloride (CCl4) through inhibition of hepatic inflammation

Various medicinal plants are traditionally used in a hepatoprotective manner, like, for example, the Litchi chinensis leaf infusion that is employed in Chinese medicine as liver tonics to strengthen hepatic functioning. In this context, the present study was designed to evaluate the hepatoprotective and acute toxicological effects of hydroethanolic L. chinensis leaf extract in HepG2 cells and mice. Specifically, the cytotoxicity and hepatoprotective activities of L. chinensis leaf extract were evaluated in HepG2 cells and in vivo against carbon tetrachloride (CCl₄)-induced acute liver injury. The administration of CCl₄ in mice provokes cell swelling, loss of sinusoid capillary spaces and structural disarrangement of the hepatic lobe, apoptosis and leukocyte infiltration. Further, CCl₄ evokes an increase in serum alanine aminotransferase (ALT), tumor necrosis factor (TNF) and interleukin-6 (IL-6) levels in hepatic tissue. However, Silymarin, the positive control, and the L. chinensis extract were able to restore the viability of cells treated with CCl₄ at all concentrations evaluated, reduced the inflammatory parameters, TNF and IL-6, reestablished hepatic tissue morphology and did not induce acute toxicological alterations. The data obtained underscore that the extract from L. chinensis leaves features hepatoprotective activity, corroborating with ethnopharmacological use, and does not lead to acute toxicological effects.

Cellular crosstalk mediated by platelet-derived growth factor BB and transforming growth factor β during hepatic injury activates hepatic stellate cells

Apoptotic hepatocytes release factors that activate hepatic stellate cells (HSCs), thereby inducing hepatic fibrosis. In the present study, in vivo and in vitro injury models were established using acetaminophen, ethanol, carbon tetrachloride, or thioacetamide. Histology of hepatotoxicant-induced diseased hepatic tissue correlated with differential expression of fibrosis-related genes. A marked increase in co-staining of transforming growth factor β receptor type II (TGFRIIβ) – desmin or α-smooth muscle actin – platelet-derived growth factor receptor β (PDGFRβ), markers of activated HSCs, in liver sections of these hepatotoxicant-treated mice also depicted an increase in Annexin V – cytokeratin expressing hepatocytes. To understand the molecular mechanisms of disease pathology, in vitro experiments were designed using the conditioned medium (CM) of hepatotoxicant-treated HepG2 cells supplemented to HSCs. A significant increase in HSC proliferation, migration, and expression of fibrosis-related genes and protein was observed, thereby suggesting the characteristics of an activated phenotype. Treating HepG2 cells with hepatotoxicants resulted in a significant increase in mRNA expression of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β (TGFβ). CM supplemented to HSCs resulted in increased phosphorylation of PDGFRβ and TGFRIIβ along with its downstream effectors, extracellular signal-related kinase 1/2 and focal adhesion kinase. Neutralizing antibodies against PDGF-BB and TGFβ effectively perturbed the hepatotoxicant-treated HepG2 cell CM-induced activation of HSCs. This study suggests PDGF-BB and TGFβ as potential molecular targets for developing anti-fibrotic therapeutics.

Hepatoprotective Effect of Steroidal Glycosides From Dioscorea villosa on Hydrogen Peroxide-Induced Hepatotoxicity in HepG2 Cells

Dioscorea villosa, commonly known as "Wild Yam" and native to North America, is well documented for its pharmacological properties due to the presence of steroidal glycosides. However, the hepatoprotective potential of these compounds has not been studied so far. The present investigation was aimed to study the hepatoprotective effect of the steroidal glycosides from D. villosa against H2O2, a known hepatotoxin, in human liver cell line (HepG2). Cytotoxicity assessment was carried out in cells exposed to various concentrations (10-50 μM) of compounds for 24 h using MTT assay and morphological changes. All tested compounds were known and among them, spirostans (zingiberensis saponin I, dioscin, deltonin and progenin III) were found to be cytotoxic whereas, furostans (huangjiangsu A, pseudoprotodioscin, methyl protobioside, protodioscin, and protodeltonin) were non-cytotoxic. Further, HepG2 cells were pretreated with biologically safe concentrations (10, 30, and 50 μM) of non-cytotoxic compounds and then cytotoxic (0.25 mM) concentration of H2O2. After 24 h, cell viability was assessed by MTT and NRU assays, while morphological changes were observed under the microscope. The results showed that treatment of HepG2 cells with compounds prior to H2O2 exposure effectively increased cell viability in a concentration-dependent manner. Furthermore, huangjiangsu A, pseudoprotodioscin, methyl protobioside, protodioscin, and protodeltonin at 50 μM increased GSH level and decreased intracellular ROS generation against H2O2-induced damages. The results from this study revealed that compounds isolated from D. villosa have hepatoprotective potential against H2O2-induced cytotoxicity and ROS generation and could be promising as potential therapeutic agents for liver diseases.