Hepatoprotective action of Orthosiphon diffusus (Benth.) methanol active fraction through antioxidant mechanisms: an in vivo and in vitro evaluation

Dual Phytochemical/Activity-Guided Optimal Preparation and Bioactive Material Basis of Orthosiphon Stamineus Benth. (Shen Tea) against Nonalcoholic Fatty Liver Disease

Orthosiphon stamineus Benth. (OSB) is a popular plant used for making "Shen tea" or "Java tea". It has been demonstrated with antioxidant, anti-inflammatory, and hepatoprotective activities. However, its potential beneficial effects and bioactive material basis for nonalcoholic fatty liver disease (NAFLD) has not been convincingly studied. In the present work, we conducted dual phytochemical/activity-guided extraction optimization and component fractionation of OSB, and evaluated its beneficial effects on NAFLD. Flavonoids and polyphenols (caffeic acid/protocatechuic acid derivatives) were determined as the dominant phytochemicals in OSB. The extraction process for these phytochemicals was optimized by using response surface methodology. Noticeably, flavonoids showed a stronger correlation with the antioxidant activities of OSB than polyphenols. Likewise, the flavonoid-rich fraction of OSB exerted antioxidant activities stronger than those of other fractions. As expected, in vitro and in vivo studies demonstrated that the flavonoid-rich fraction effectively attenuated weight increase, improved lipid metabolism, alleviated hepatic steatosis, and reversed hepatic inflammation. Importantly, this fraction showed equivalent beneficial effects to the total extract of OSB, suggesting that flavonoids were the main bioactive constituents of OSB. The action mechanism was indicated as direct antioxidant effect through chemical interaction with free radicals and indirect mitochondria-mediated antioxidant defense. Our research offers bioactive substances for further exploitation and expands the potential application of OSB.

Hepatoprotective and antioxidant effect of Adiantum lunulatum Burm. F. leaf in alcohol-induced rat model

Background Adiantum lunulatum Burm. F. leaf (AL) and its related species have been used traditionally for the treatment of various diseases. Objective The present study evaluated the hepatoprotective, and antioxidant activities of ethanolic extract of AL. Methodology and Result The hepatoprotective effect of AL was evaluated against ethanol-induced hepatotoxicity in rats. Administration of ethanol (2 g/kg) showed a significant biochemical and histological deterioration in the liver of experimental animals. Pretreatment with ethanolic extract of AL (250 and 500 mg/kg b.wt. p.o) significantly reduced the elevated levels of serum enzymes like serum glutamic-oxaloacetic transaminase (AST), serum glutamic-pyruvic transaminase (ALT), alkaline phosphatase (ALP), total protein, total bilirubin and reversed the hepatic damage in the liver which evidenced the hepatoprotective activity. The superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) level notably increased due to doses of AL. Conclusion The results of the present study demonstrate that the ethanolic extract of AL possesses hepatoprotective and antioxidant activities. Graphical Abstract.

Antifibrogenic Influence of Mentha piperita L. Essential Oil against CCl4-Induced Liver Fibrosis in Rats

Essential oils of some aromatic plants provide an effective nonmedicinal option to control liver fibrosis. Mentha piperita L. essential oil (MPEO) have been reported to possess protective effects against hepatotoxicity. However, its effect against liver fibrosis remains unknown. The present study investigated the antifibrogenic potential of MPEO and its underlying mechanisms. Forty male rats divided into 4 groups were used: group 1 served as normal control, group 2 (liver fibrosis) received CCl4 (2.5 mL/kg, IP, twice weekly) for 8 weeks, group 3 concurrently received CCl4 plus MPEO (50 mg/kg, IP, daily, from the 3rd week), and group 4 received MPEO only. MPOE significantly improved the liver injury markers, lipid peroxidation (LPO), antioxidant capacity, CYP2E1 gene expressionand liver histology. Furthermore, MPOE ameliorated liver fibrosis as evidenced by the reduced expression of desmin, α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and SMAD3 proteins. In addition, MPOE counteracted the p53 upregulation induced by CCl4 at both mRNA and protein levels. In conclusion, MPOE could effectively attenuate hepatic fibrosis mainly through improving the redox status, suppressing p53 and subsequently modulating TGF-β1 and SMAD3 protein expression. These data promote the use of MPOE as a promising approach in antifibrotic therapy.

Neoboutonia melleri var velutina Prain: in vitro and in vivo hepatoprotective effects of the aqueous stem bark extract on acute hepatitis models

BACKGROUND

Hepatitis is a liver inflammation caused by different agents and remains a public health problem worldwide. Medicinal plants are an important source of new molecules being considered for treatment of this disease. Our work aims at evaluating the hepatoprotective properties of Neoboutonia velutina, a Cameroonian medicinal plant.

METHODS

The aqueous extract has been prepared using phytochemical methods. HepG2 cells were used to assess anti-inflammatory properties of the extract at different concentrations. Acute hepatitis models (Carbon tetrachloride and Concanavalin A) were performed in mice receiving or not receiving, different extract doses by gavage. Liver injury was assessed using histology, transaminases and pro-inflammatory markers. Extract antioxidant and radical scavenging capacities were evaluated.

RESULTS

The extract led to a significant decrease in pro-inflammatory cytokine expression in vitro and to a remarkable protection of mice from carbon tetrachloride-induced liver injury, as shown by a significant decrease in dose-dependent transaminases level. Upon extract treatment, inflammatory markers were significantly decreased and liver injuries were limited as well. In the Concanavalin A model, the extract displayed weak effects.

CONCLUSIONS

Taking into account underlying mechanisms in both hepatitis models, we demonstrate the extract's radical scavenging capacity. Neoboutonia velutina displays a potent hepatoprotective effect mediated through radical scavenging properties.

Identification of the compositional changes in Orthosiphon stamineus leaves triggered by different drying techniques using 1 H NMR metabolomics

BACKGROUND

Java tea is a well-known herbal infusion prepared from the leaves of Orthosiphon stamineus (OS). The biological properties of tea are in direct correlation with the primary and secondary metabolite composition, which in turn largely depends on the choice of drying method. Herein, the impact of three commonly used drying methods, i.e. shade, microwave and freeze drying, on the metabolite composition and antioxidant activity of OS leaves was investigated using proton nuclear magnetic resonance (¹ H NMR) spectroscopy combined with multivariate classification and regression analysis tools.

RESULTS

A total of 31 constituents comprising primary and secondary metabolites belonging to the chemical classes of fatty acids, amino acids, sugars, terpenoids and phenolic compounds were identified. Shade-dried leaves were identified to possess the highest concentrations of bioactive secondary metabolites such as chlorogenic acid, caffeic acid, luteolin, orthosiphol and apigenin, followed by microwave-dried samples. Freeze-dried leaves had higher concentrations of choline, amino acids leucine, alanine and glutamine and sugars such as fructose and α-glucose, but contained the lowest levels of secondary metabolites.

CONCLUSION

Metabolite profiling coupled with multivariate analysis identified shade drying as the best method to prepare OS leaves as Java tea or to include in traditional medicine preparation. © 2017 Society of Chemical Industry.

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

BACKGROUND

In vitro bioassays are important in the evaluation of plants with possible hepatoprotective effects. The aims of this study were to evaluate the pretreatment of HepG2 cells with hepatoprotective agents against the damage induced by carbon tetrachloride (CCl₄) and paracetamol (APAP).

METHODS

Antioxidative activity was measured using an assay to measure 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. The in vitro hepatotoxicity of CCl₄ and APAP, and the cytotoxic and hepatoprotective properties of silymarin (SLM), silybinin (SLB), and silyphos (SLP) were evaluated by measuring cell viability; activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH); total antioxidant capacity (TAOxC); and reduced glutathione (GSH), superoxide dismutase (SOD), and lipid peroxidation (malondialdehyde (MDA) levels).

RESULTS

Only SLB and SLM showed strong antioxidative activity in the DPPH assay (39.71 ± 0.85 μg/mL and 14.14 ± 0.65 μg/mL, respectively). CCl₄ induced time- and concentration-dependent changes. CCl₄ had significant effects on cell viability, enzyme activities, lipid peroxidation, TAOxC, and SOD and GSH levels. These differences remained significant up to an exposure time of 3 h. APAP induced a variety of dose- and time-dependent responses up to 72 h of exposure. SLM, SLB, and SLP were not cytotoxic. Only SLB at a concentration of 100 μg/mL or 150 μg/mL significantly decreased the enzyme activities and MDA level, and prevented depletion of total antioxidants compared with CCl₄.

CONCLUSIONS

CCl₄ was more consistent than APAP in inducing cell injury. Only SLB provided hepatoprotection. AST, LDH, and MDA levels were good markers of liver damage.

Rosmarinic acid mediated neuroprotective effects against H2O2-induced neuronal cell damage in N2A cells

AIMS

Oxidative stress plays a key role in several ailments including neurodegenerative conditions. The aim of the study was to demonstrate the effect of rosmarinic acid (RA) in preventing oxidative stress related death of neuronal cell lines.

MAIN METHODS

In the present study, we demonstrated direct neuroprotective effect of RA using H2O2-induced oxidative challenge in N2A mouse neuroblastoma cells. The mechanism of neutralization of H2O2-induced toxicity by RA was evaluated using MTT, lactate dehydrogenase, mitochondrial membrane potential (MMP), intracellular ROS, and comet assays. Up-regulation of brain neuronal markers at molecular level was performed by RT-PCR.

KEY FINDINGS

Results presented in the paper indicate that H2O2-induced cytotoxicity in N2A cells was suppressed by treatment with RA. Moreover, RA is very effective in attenuating the disruption of lactate dehydrogenase, mitochondrial membrane potential and intracellular ROS. Pretreatment with RA significantly prevents genotoxicity (3.7-fold, p<0.01) and promotes the up-regulation of tyrosine hydroxylase (TH) (4.5-fold, p<0.01), and brain-derived neurotrophic factor (BDNF) genes (5.4-fold, p<0.01) against H2O2-induced cytotoxicity in N2A cells.

SIGNIFICANCE

Our results revealed that N2A cells are suitable cellular models to evaluate neuroprotective effects of RA, and suggest that RA may potentially serve as an agent for prevention of several human neurodegenerative diseases caused by oxidative stress.