In vitro and in vivo antifibrotic effects of rosmarinic acid on experimental liver fibrosis

Ultrasound-assisted extraction of carnosic acid and rosmarinic acid using ionic liquid solution from Rosmarinus officinalis

Ionic liquid based, ultrasound-assisted extraction was successfully applied to the extraction of phenolcarboxylic acids, carnosic acid and rosmarinic acid, from Rosmarinus officinalis. Eight ionic liquids, with different cations and anions, were investigated in this work and [C(8)mim]Br was selected as the optimal solvent. Ultrasound extraction parameters, including soaking time, solid-liquid ratio, ultrasound power and time, and the number of extraction cycles, were discussed by single factor experiments and the main influence factors were optimized by response surface methodology. The proposed approach was demonstrated as having higher efficiency, shorter extraction time and as a new alternative for the extraction of carnosic acid and rosmarinic acid from R. officinalis compared with traditional reference extraction methods. Ionic liquids are considered to be green solvents, in the ultrasound-assisted extraction of key chemicals from medicinal plants, and show great potential.

Rosmarinic acid and its derivatives: biotechnology and applications

Rosmarinic acid (RA) is one of the first secondary metabolites produced in plant cell cultures in extremely high yields, up to 19% of the cell dry weight. More complex derivatives of RA, such as rabdosiin and lithospermic acid B, later were also obtained in cell cultures at high yields. RA and its derivatives possess promising biological activities, such as improvement of cognitive performance, prevention of the development of Alzheimer's disease, cardioprotective effects, reduction of the severity of kidney diseases and cancer chemoprevention. The TNF-α-induced NF-κB signaling pathway has emerged as a central target for RA. Despite these impressive activities and high yields, the biotechnological production of these metabolites on an industrial scale has not progressed. We summarized data suggesting that external stimuli, the Ca(2+)-dependent NADPH oxidase pathway and processes of protein phosphorylation/dephosphorylation are involved in the regulation of biosynthesis of these substances in cultured plant cells. In spite of growing information about pathways regulating biosynthesis of RA and its derivatives in cultured plant cells, the exact mechanism of regulation remains unknown. We suggest that further progress in the biotechnology of RA and its derivatives can be achieved by using new high-throughput techniques.

[Importance of dietary hydroxycinnamic acids in the therapy of liver fibrosis]

Medicinal treatment of liver fibrosis is still unsolved. According to literature data, plant extracts containing hydroxycinnamic acids inhibit experimentally induced liver fibrosis.

AIM

The aim of this study was to provide data on the hydroxycinnamic acid content of medicinal plants, which can be applied in the adjuvant therapy of liver fibrosis.

METHODS

Content and composition of hydroxycinnamic acids from houseleek and seven known herbs were evaluated using spectrophotometry and high-performance liquid chromatography.

RESULTS

Hydroxycinnamic acid content was found to be high in Lamiaceae herbs, but it was lower in houseleek. Rosmarinic acid as the main compound was detected in all herb samples.

CONCLUSIONS

Besides hydroxycinnamic acids, houseleek contains high amounts of antioxidant polyphenols, and its pharmacological effect is presumed to be attributed to synergism of all of these compounds. The hydroxycinnamic acid content of the herbs investigated was remarkable, therefore, the results support their dietary application in patients with chronic liver disease.

Antifibrotic effects of protocatechuic aldehyde on experimental liver fibrosis

BACKGROUND

Recent studies have demonstrated that transforming growth factor-β1 (TGF-β1) and connective transforming growth factor (CTGF) are associated with the pathophysiology of liver fibrosis. We isolated protocatechuic aldehyde, the major degradation of phenolic acids.

OBJECTIVE

This study was carried out to investigate the potential antifibrotic effect of Protocatechuic aldehyde (PA) on experimental liver fibrosis in vitro and in vivo, and to explore its possible mechanism.

MATERIALS AND METHODS

Cell proliferation was determined. Type I collagen, type III collagen, transforming growth factor-β1 (TGF-β1) and connective transforming growth factor (CTGF) were measured by ELISA kits in TNF-α stimulated HSCs. In the carbon tetrachloride (CCL(4))-induced rat liver fibrosis model, liver fibrosis grade and histopathological changes were evaluated, and biochemical indicators were determined. Furthermore, immunostaining and Western blot analysis were used to detect hepatic TGF-β1 and CTGF expression in liver tissue.

RESULTS

Overall, our results indicated that PA inhibits HSCs proliferation, inhibits the levels of TGF-β1, CTGF, type I collagen and type III collagen in TNF-α stimulated HSCs. Treatment of PA causes a significant reduction in fibrosis grade, ameliorates biochemical indicators and histopathological morphology, and reduces liver TGF-β1 and CTGF expression in rat model of CCL(4)-induced liver fibrosis.

CONCLUSION

These findings suggest that PA has potentially conferring antifibrogenic effects.

Effect of rosmarinic acid on experimental diabetic nephropathy

Connective tissue growth factor (CTGF) plays a pathogenic role in diabetic nephropathy (DN). Rosmarinic acid (RA) is a naturally occurring phenolic acid. This study was conducted to investigate the efficacy of RA on DN and to elucidate the potential mechanism. High glucose (HG)-stimulated cultured human renal proximal tubular epithelial cells (HK-2) analysed CTGF expression by western blotting, and it was investigated whether extracellular signal-regulated kinase (ERK) signalling pathway was involved. Using streptozotocin (STZ)-induced rat animal models, diabetic rats were randomized to receive intragastric (i.g.) doses of RA. Renal tissue, blood and urine samples were collected to determine biochemical index and analyse protein expression. In vitro study, RA reduced CTGF excretion in HG-induced HK-2 cells through the ERK signalling pathway. In an in vivo study, I.g. of RA 7.5 or 15 mg/kg significantly ameliorated renal function and increased body-weight. Meanwhile, RA reduced renal CTGF expression by immunohistochemical staining and reduced serum levels of CTGF. Besides, there were no significant differences in glycaemia levels between the RA groups compared with the STZ-treated group. Furthermore, RA ameliorated renal pathology. These results suggest that RA exerts an early renal protective role to DN. Inhibition of CTGF may be a potential target in DN therapy, which highlights the possibility of using RA in the treatment of DN.

Rosmarinic acid and baicalin epigenetically derepress peroxisomal proliferator-activated receptor γ in hepatic stellate cells for their antifibrotic effect

Hepatic stellate cells (HSCs) undergo myofibroblastic transdifferentiation (activation) to participate in liver fibrosis and identification of molecular targets for this cell fate regulation is essential for development of efficacious therapeutic modalities for the disease. Peroxisomal proliferator-activated receptor γ (PPARγ) is required for differentiation of HSCs and its epigenetic repression underlies HSC activation. The herbal prescription Yang-Gan-Wan (YGW) prevents liver fibrosis, but its active ingredients and molecular mechanisms are unknown. Here we demonstrate YGW prevents and reverses HSC activation by way of epigenetic derepression of Pparγ involving reductions in MeCP2 expression and its recruitment to Pparγ promoter, suppressed expression of PRC2 methyltransferase EZH2, and consequent reduction of H2K27di-methylation at the 3' exon. High-performance liquid chromatography / mass spectrometry (HPLC/MS) and nuclear magnetic resonance (NMR) analyses identify polyphenolic rosmarinic acid (RA) and baicalin (BC) as active phytocompounds. RA and BC suppress the expression and signaling by canonical Wnts, which are implicated in the aforementioned Pparγ epigenetic repression. RA treatment in mice with existing cholestatic liver fibrosis inhibits HSC activation and progression of liver fibrosis.

CONCLUSION

These results demonstrate a therapeutic potential of YGW and its active component RA and BC for liver fibrosis by way of Pparγ derepression mediated by suppression of canonical Wnt signaling in HSCs.

Predicting in vivo anti-hepatofibrotic drug efficacy based on in vitro high-content analysis

Background/Aims

Many anti-fibrotic drugs with high in vitro efficacies fail to produce significant effects in vivo. The aim of this work is to use a statistical approach to design a numerical predictor that correlates better with in vivo outcomes.

Methods

High-content analysis (HCA) was performed with 49 drugs on hepatic stellate cells (HSCs) LX-2 stained with 10 fibrotic markers. ∼0.3 billion feature values from all cells in >150,000 images were quantified to reflect the drug effects. A systematic literature search on the in vivo effects of all 49 drugs on hepatofibrotic rats yields 28 papers with histological scores. The in vivo and in vitro datasets were used to compute a single efficacy predictor (E_predict).

Results

We used in vivo data from one context (CCl₄ rats with drug treatments) to optimize the computation of E_predict. This optimized relationship was independently validated using in vivo data from two different contexts (treatment of DMN rats and prevention of CCl₄ induction). A linear in vitro-in vivo correlation was consistently observed in all the three contexts. We used E_predict values to cluster drugs according to efficacy; and found that high-efficacy drugs tended to target proliferation, apoptosis and contractility of HSCs.

Conclusions

The E_predict statistic, based on a prioritized combination of in vitro features, provides a better correlation between in vitro and in vivo drug response than any of the traditional in vitro markers considered.

Antioxidant and antigenotoxic effects of rosemary (Rosmarinus officinalis L.) extracts in Salmonella typhimurium TA98 and HepG2 cells

In the present study the chemopreventive effects of water soluble AquaROX(®) 15 and oil soluble VivOX(®) 40 rosemary extracts against 4-nitroquinoline-N-oxide (NQNO) and 2-amino-3-methyl-3H-imidazo[4,5-F]quinoline (IQ) induced mutagenicity in the reverse mutation assays with Salmonella typhimurium TA98 and against t-butyl hydroperoxide (t-BOOH), benzo(a)pyrene (BaP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced DNA damage in HepG2 cells were studied, applying the comet assay. The results showed comparable protective effect of AquaROX and VivOX against oxidative DNA damage, whereas protection against indirect active genotoxic carcinogens was more efficient by VivOX.

Storage method, drying processes and extraction procedures strongly affect the phenolic fraction of rosemary leaves: an HPLC/DAD/MS study

The Rosmarinus officinalis L. is widely known for its numerous applications in the food field but also for the increasing interest in its pharmaceutical properties. Two groups of compounds are mainly responsible for the biological activities of the plant: the volatile fraction and the phenolic constituents. The latter group is mainly constituted by rosmarinic acid, by a flavonoidic fraction and by some diterpenoid compounds structurally derived from the carnosic acid. The aim of our work was to optimize the extractive and analytical procedure for the determination of all the phenolic constituents. Moreover the chemical stability of the main phenols, depending on the storage condition, the different drying procedures and the extraction solvent, have been evaluated. This method allowed to detect up to 29 different constituents at the same time in a relatively short time. The described procedure has the advantage to being able to detect and quantify several classes of compounds, among them numerous minor flavonoids, thus contributing to improving knowledge of the plant. The findings from this study have demonstrated that storing the raw fresh material in the freezer is not appropriate for rosemary, mainly due to the rapid disappearing of the rosmarinic acid during the freezing/thawing process. Regarding the flavonoidic fraction, consistent decrements, were highlighted in the dried samples at room temperature if compared with the fresh leaf. Rosmarinic acid, appeared very sensitive also to mild drying processes. The total diterpenoidic content undergoes to little changes when the leaves are freeze dried or frozen and limited losses are observed working on dried leaves at room temperature. Nevertheless it can be taken in account that this fraction is very sensitive to the water presence during the extraction that favors the conversion of carnosic acid toward it oxidized form carnosol. From our findings, it appear evident that when evaluating the phenolic content in rosemary leaves, several factors, mainly the type of storage, the drying process and the extraction methods, should be carefully taken into account because they can induce partial losses of the antioxidant components.

Zingiber officinale acts as a nutraceutical agent against liver fibrosis

Background/objective

Zingiber officinale Roscoe (ginger) (Zingiberaceae) has been cultivated for thousands of years both as a spice and for medicinal purposes. Ginger rhizomes successive extracts (petroleum ether, chloroform and ethanol) were examined against liver fibrosis induced by carbon tetrachloride in rats.

Results

The evaluation was done through measuring antioxidant parameters; glutathione (GSH), total superoxide dismutase (SOD) and malondialdehyde (MDA). Liver marker enzymes; succinate and lactate dehydrogenases (SDH and LDH), glucose-6-phosphatase (G-6-Pase), acid phosphatase (AP), 5'- nucleotidase (5'NT) and liver function enzymes; aspartate and alanine aminotransferases (AST and ALT) as well as cholestatic markers; alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total bilirubin were estimated. Liver histopathological analysis and collagen content were also evaluated. Treatments with the selected extracts significantly increased GSH, SOD, SDH, LDH, G-6-Pase, AP and 5'NT. However, MDA, AST, ALT ALP, GGT and total bilirubin were significantly decreased.

Conclusions

Extracts of ginger, particularly the ethanol one resulted in an attractive candidate for the treatment of liver fibrosis induced by CCl₄. Further studies are required in order to identify the molecules responsible of the pharmacological activity.

Rosmarinic acid inhibits proliferation and induces apoptosis of hepatic stellate cells

Hepatic stellate cells (HSCs), activated during liver injury, are defined as the most important target in the therapy of hepatic fibrosis. In the present study, we evaluated the effect of Rosmarinic acid (RosA) on the proliferation and apoptosis in activated hepatic stellate cells (HSC-T6), which is useful to decrease this cell population. The proliferation of HSC-T6 was significantly inhibited after treated with various concentrations of RosA for different times. Flow cytometric analyses and transmission electron microscope (TEM) observations revealed that HSC-T6 treated with RosA underwent apoptosis in a time dependent manner and displayed typical apoptotic features in the cells. The phosphorylation in signal transducer and activator of transcription protein-3 (STAT3), which regulates cell survival, proliferation and differentiation in a variety of tissues, was markedly decreased as the result of Western blot assay and correlated with downregulation of CyclinD1 and B cell lymphoma/leukemia-2 (Bcl-2). In conclusion, these results suggested that RosA was able to inhibit proliferation and induce apoptosis in HSC-T6, partly due to the inhibition of phosphorylation in STAT3, which contributed to the reversal of hepatic fibrosis.

Therapeutic effects of SMND-309, a new metabolite of salvianolic acid B, on experimental liver fibrosis

(2E)-2-{6-[(E)-2-carboxylvinyl]-2,3-dihydroxyphenyl}-3-(3,4-dihydroxyphenyl) propenoic acid, a novel compound designated SMND-309, is a new metabolite of salvianolic acid B. The present study was carried out to investigate the effects of SMND-309 on experimental liver fibrosis in rats induced by subcutaneous injection of carbon tetrachloride and explore its possible mechanisms on the basis of biochemical, histopathologic and immunohistochemical studies. The results showed that intragastrical treatment with SMND-309 ameliorated liver function and decreased the elevation of serum hyaluronic acid, laminin, procollagen type III levels and hydroxyproline content in liver tissue. It also decreased the elevation in the malondialdehyde level and restored the decrease in superoxide dismutase and glutathione peroxidase activities. Upon histopathologic examination, the SMND-309-treated rats reduced the liver damage and the liver fibrosis grade. Moreover, the results of immunohistochemical examination showed that SMND-309 powerfully down-regulated the expression of connective tissue growth factor (CTGF) rather than transforming growth factor-beta1 (TGF-β1) in serum and liver. Meanwhile, SMND-309 exhibits significantly higher potency compared with salvianolic acid B (Sal B) at the same dose. The antifibrotic mechanisms of SMND-309 might be associated with its ability to suppress the expression of CTGF as well as scavenge lipid peroxidation products and increase endogenous antioxidant enzyme activity.