Protective effect of daidzin against D-galactosamine and lipopolysaccharide-induced hepatic failure in mice

Sedative Effects of Daidzin, Possibly Through the GABAA Receptor Interaction Pathway: In Vivo Approach with Molecular Dynamic Simulations

The soy isoflavone daidzin (DZN) has been considered a hopeful bioactive compound having diverse biological activities, including anxiolytic, memory-enhancing, and antiepileptic effects, in experimental animals. However, its sedative and hypnotic effects are yet to be discovered. This study aimed to evaluate its sedative/hypnotic effect on Swiss mice. Additionally, in silico studies were also performed to see the possible molecular mechanisms behind the tested neurological effect. For this, male Swiss albino mice were treated with DZN (5, 10, or 20 mg/kg) intraperitoneally (i.p.) with or without the standard GABAergic medication diazepam (DZP) and/or flumazenil (FLU) and checked for the onset and duration of sleeping time using thiopental sodium-induced as well as DZP-induced sleeping tests. A molecular docking study was also performed to check its interaction capacity with the α1 and β2 subunits of the GABAA receptor. Findings suggest that DZN dose-dependently and significantly reduced the latency while increasing the duration of sleep in animals. In combination therapy, DZN shows synergistic effects with the DZP-2 and DZP-2 + FLU-0.01 groups, resulting in significantly (p < 0.05) reduced latency and increased sleep duration. Further, molecular docking studies demonstrate that DZN has a strong binding affinity of - 7.2 kcal/mol, which is closer to the standard ligand DZP (- 8.3 kcal/mol) against the GABAA (6X3X) receptor. Molecular dynamic simulations indicated stability and similar binding locations for DZP and DZN with 6X3X. In conclusion, DZN shows sedative effects on Swiss mice, possibly through the GABAA receptor interaction pathway.

Daidzein ameliorated concanavalin A-induced liver injury through the Akt/GSK-3β/Nrf2 pathway in mice

Background

Daidzein is a soybean isoflavone that has been shown in previous studies to have anti-inflammatory and antioxidant effects. However, it remains unknown whether daidzein plays a protective role against concanavalin A (Con A)-induced autoimmune hepatitis (AIH).

Methods

In this study, an animal model of AIH was constructed by intravenous injection of Con A (15 mg/kg). Daidzein (200 mg/kg/d) was intraperitoneally administered to mice for 3 days before the Con A injection. Alpha mouse liver 12 (AML-12) cells were incubated in the absence or presence of daidzein to determine whether daidzein can alleviate Con A-induced hepatotoxicity.

Results

The findings showed that pretreatment with daidzein significantly reduced Con A-induced oxidative stress and hepatocyte apoptosis in Con A-induced liver injury. Pretreatment with daidzein significantly prevented the decrease of intrahepatic protein levels of phosphorylated Akt (p-Akt), phosphorylated GSK3β (p-GSK3β), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NOQ1 (NAD(P)H quinone dehydrogenase 1) in response to Con A administration. Meanwhile, malondialdehyde (MDA) production was reduced, and glutathione peroxidase (GPX), superoxide dismutase (SOD) activity, and SOD2 mRNA expression were elevated in daidzein-pretreated livers. In in vitro experiments, daidzein pretreatment prevented Con A-induced murine hepatocyte death. This effect was partly diminished by an inhibitor of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway.

Conclusions

These results indicate that daidzein pretreatment attenuates Con A-induced liver injury through the Akt/GSK3β/Nrf2 pathway. Our findings provide new insights into the use of plant-derived products for AIH treatment beyond immunosuppression.

Potential Effects of Dietary Isoflavones on Drug-Induced Liver Injury

Numerous prescribed drugs and herbal and dietary supplements have been reported to cause drug-induced acute liver injury, which is a frequent cause of acute liver failure (ALF). It is a tremendous challenge with ever-increasing drug application in the medication system for huge populations. Drug-induced acute liver injury can lead to diverse pathologies similar to acute and chronic hepatitis, acute liver failure, biliary obstruction, fatty liver disease, and so on. Recently, extensive work demonstrated that isoflavones play an essential and protecting role in drug-induced liver injury (DILI). The isoflavones mediated hepatoprotection by modulating specific genes linked with control of cellular redox homeostasis and inflammatory responses. Isoflavones upregulate oxidative stress-responsive nuclear factor erythroid 2-like 2 (Nrf2), downregulate inflammatory nuclear factor-κB (NF-κB) signaling pathways, and modulate a balance between cell survival and death. Moreover, isoflavones actively inhibit the expression of cytochromes P450 (CYPs) enzyme during drug metabolism. Moreover, isoflavones are also linked with farnesoid X receptor (FXR) activation and signal transducer and activator of transcription factor 3 (STAT3) phosphorylation in hepatoprotection DILI. In vivo and in vitro studies clearly stated that isoflavones bear strong antioxidant potential and promising agents for hepatotoxicity prevention and stressed their potential role as therapeutic supplements in DILI. The current review will elaborate on isoflavones’ preventive and therapeutic potential concisely and highlight various molecular targets to exert a protective effect on DILI.

Pterostilbene Exerts Hepatoprotective Effects through Ameliorating LPS/D-Gal-Induced Acute Liver Injury in Mice

Acute liver injury (ALI) refers to abnormalities in liver function caused by various causes and accompanied by poor prognosis and high mortality. Common predisposing factors for the disease are viral hepatitis, bacteria, alcohol, and certain hepatotoxic drugs. Inflammatory response and oxidative stress are critical for the pathogenesis of ALI. Pterostilbene (Pte), a natural polyphenol product extracted from blueberries and grapes, has been reported that exerted multiple biological activities, including antioxidative, anti-inflammatory, anti-carcinogenic, and anti-apoptotic properties. However, there is very little data showing the hepatoprotective effect of Pte on lipopolysaccharide/D-galactosamine (LPS/D-Gal)-induced ALI in mice. In this study, the possible protective effect and potential mechanisms of Pte on ALI are being investigated. It has been found that Pte markedly ameliorates LPS/D-Gal-induced inflammatory infiltration, hemorrhage, and dissociation of the hepatic cord, reducing the myeloperoxidase (MPO) activity in liver tissues and serum levels of alanine transaminase (ALT) and aspartate aminotransferase (AST) in ALI. Pte also inhibits LPS/D-Gal-induced secretion of pro-inflammatory cytokine tumor necrosis factor-a (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β) in liver tissues. Furthermore, the western blot analysis reveals that LPS/D-Gal-activated nuclear factor-kappa B (NF-κB) is significantly inhibited by Pte, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) are upregulated by Pte. In conclusion, our results suggest that Pte exerts anti-inflammatory and antioxidative effects, which might contribute to ameliorating LPS/D-Gal-induced ALI in mice. Pte has the potential to be a preventive hepatoprotective agent.

New hepatoprotective isoflavone glucosides from Pueraria lobata (Willd.) Ohwi

Two new isoflavone glucosides, 3'-methoxyneopuerarin A (1) and 3'-methoxyneopuerarin B (2), together with nine known isoflavones including puerarin (3), neopuerarin A (4), neopuerarin B (5), daidzin (6), daidzein (7), 3'-methoxypuerarin (PG-3) (8), puerarin xyloside (9), mirificin (10), 3'-hydroxypuerarin (11) were isolated from the water extraction of the dried roots of Pueraria lobata (Willd.) Ohwi. Their structures were elucidated by the means of spectroscopic and chromatographic analysis methods. All compounds were evaluated for their hepatoprotective activity on HepG2 cells. All of them showed statistically significant hepatoprotective effect.

Screening potential mitochondria-targeting compounds from traditional Chinese medicines using a mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry method

Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry (LC/MS) method, also known as screening method for mitochondria-targeted bioactive constituents (SM-MBC). This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines (TCMs), including Puerariae Radix (PR) and Chuanxiong Radix (CR). A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on HepG2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.

Comparative Evaluation of the Antioxidant and Anti-Alzheimer's Disease Potential of Coumestrol and Puerarol Isolated from Pueraria lobata Using Molecular Modeling Studies

The current study assesses the antioxidant effects of two similar isoflavonoids isolated from Pueraria lobata, coumestrol and puerarol, along with the cholinergic and amyloid-cascade pathways to mitigate Alzheimer’s disease (AD). Antioxidant activity was evaluated via 1,1-diphenyl-2-picryhydrazyl (DPPH) and peroxynitrite (ONOO⁻) scavenging ability further screened via ONOO⁻-mediated nitrotyrosine. Similarly, acetyl- and butyrylcholinesterase (AChE/BChE) and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities were assessed together with docking and kinetic studies. Considering DPPH and ONOO⁻ scavenging activity, coumestrol (EC₅₀ values of 53.98 and 1.17 µM) was found to be more potent than puerarol (EC₅₀ values of 82.55 and 6.99 µM) followed by dose dependent inhibition of ONOO⁻-mediated nitrotyrosine. Coumestrol showed pronounced AChE and BChE activity with IC₅₀ values of 42.33 and 24.64 µM, respectively, acting as a dual cholinesterase (ChE) inhibitor. Despite having weak ChE inhibitory activity, puerarol showed potent BACE1 inhibition (28.17 µM). Kinetic studies of coumestrol showed AChE and BChE inhibition in a competitive and mixed fashion, whereas puerarol showed mixed inhibition for BACE1. In addition, docking simulations demonstrated high affinity and tight binding capacity towards the active site of the enzymes. In summary, we undertook a comparative study of two similar isoflavonoids differing only by a single aliphatic side chain and demonstrated that antioxidant agents coumestrol and puerarol are promising, potentially complementary therapeutics for AD.

Screening of hepatoprotective compounds from licorice against carbon tetrachloride and acetaminophen induced HepG2 cells injury

BACKGROUND

Licorice and its constituents, especially licorice flavonoids have been reported to possess significant hepatoprotective activities. However, previous studies mainly focus on the extract and major compounds, and few reports are available on other licorice compounds.

PURPOSE

This work aims to evaluate the in vitro hepatoprotective activities of licorice compounds and screen active compounds, and to establish the structure-activity relationship.

METHODS

A compound library consisting of 180 compounds from three medicinal licorice species, Glycyrrhiza uralensis, G. glabra and G. inflata was established. HepG2 cells were incubated with the compounds, together with the treatment of 0.35% CCl₄ for 6 h and 14 mM APAP for 24 h, respectively.

RESULTS

A total of 62 compounds at 10 µM showed protective effects against CCl₄ to improve cell viability from 52.5% to >60%, and compounds 5 (licoflavone A), 104 (3,4-didehydroglabridin), 107 (isoliquiritigenin), 108 (3,4,3',4'-tetrahydroxychalcone), and 111 (licochalcone B) showed the most potent activities, improving cell viability to >80%. And 64 compounds showed protective effects against APAP to improve cell viability from 52.0% to >60%, and compounds 47 (derrone), 76 (xambioona), 77 ((2S)-abyssinone I), 107 (isoliquiritigenin), 118 (licoagrochalcone A), and 144 (2'-O-demethybidwillol B) showed the most potent activities, improving cell viability to >80%. Preliminary structure-activity analysis indicated that free phenolics compounds especially chalcones showed relatively stronger protective activities than other types of compounds.

CONCLUSION

Compounds 5, 76, 104, 107, 111, 118 and 144 possess potent activities against both CCl₄ and APAP, and 5, 76 and 118 were reported for the first time. They could be the major active compounds of licorice for the treatment of liver injury.

The anti-inflammatory activities of ethanol extract from Dan-Lou prescription in vivo and in vitro

Background

Although, Dan-Lou prescription (DLP) is used for antagonizing check discomfort and heartache, the pharmacological mechanism has not been clearly illustrated. Our present study aimed to design inflammatory models induced by LPS in vivo and in vitro to investigate the anti-inflammation of DLP ethanol extract (EEDL) and the potential mechanisms.

Methods

EEDL was prepared and then analyzed by high performance liquid chromatography (HPLC). Further, the anti-inflammatory effects of EEDL in vivo was evaluated by measuring inflammation-associated factors includingcytokines, chemokines and acute phase proteins in lipopolysaccharide (LPS)-induced mice serum and liver. The anti-inflammatory mechanism exploration of EEDL was performed in LPS-stimulated RAW 264.7 cells. Different effects of EEDL on nitric oxide (NO) and prostaglandin (PG)E₂ secretion were investigated by Griess reagent method and enzyme-linked immunosorbent assay (ELISA) respectively. Then the mRNA and protein expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were measured by real-time reverse-transcription polymerase chain reaction (RT-PCR), ELISA and Western blot. Other chemokines and acute phase proteins were determined by proteome profile array. Finally, the ELISA based transcription factor assay was applied to measure the DNA-binding activity of nuclear transcription factor (NF)-κB p65.

Results

Eight compounds from EEDL have been identified as gallic acid, salvianic acid, puerarin, daidzin, paeoniflorin, salvianolic acid B, cryptotanshinone, and tanshinone IIA, with amounts of 0.26, 9.84, 10.41, 2.55, 9.44, 3.82, 0.24 and 0.3 mg/kg, respectively. In vivo, EEDL administration antagonized the up-regulation of more than 17 kinds of cytokines, chemokines and acute phase proteins in LPS-treated mice serum, and inhibited LPS-induced IL-6 mRNA and protein expression in mice liver tissue. In vitro, LPS-induced NO and PGE₂ over-productions were decreased by EEDL treatment. The mRNA and protein expression of iNOS, COX-2 and IL-6 were similarly inhibited by EEDL treatment, which might be attributed to decrease the DNA-binding activity of NF-κB p65.

Conclusion

EEDL was valid for anti-inflammation and the potential molecular mechanisms might be due to the inhibition of of LPS-induced iNOS/NO, COX-2/PGE₂ and cytokines expression by antagonizing the activation of NF-κB p65.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0848-4) contains supplementary material, which is available to authorized users.

Anti-obese and anti-diabetic effects of a mixture of daidzin and glycitin on C57BL/6J mice fed with a high-fat diet

We investigated the effects of a mixture of daidzin and glycitin, which are the glycoside-form isoflavones of daidzein and glycitein, respectively, on body weight, lipid levels, diabetic markers, and metabolism in a high-fat diet (HF) fed C57BL/6J mice for 92 days. The mice were divided into basic diet group (CON), HF group, and HF companied with the isoflavone mixture group (HFISO). Results showed that mice in HFISO had a significantly lower body weight and adipose tissue compared to HF group. Blood glucose, serum HbA1c, and serum insulin also showed lower levels in HFISO group. In addition, higher hepatic GSH level and lower serum 8-hydroxy-2'-deoxyguanosine (8-OHdG) level were found in HFISO group mice. This suggests that the regulation of oxidative stress by daidzin and glycitin was closely related to the suppression of adipose tissue and the progression of diabetes.

Effects of Pueraria mirifica and miroestrol on the antioxidation-related enzymes in ovariectomized mice

OBJECTIVES

The influences of Pueraria candollei var. mirifica (PM), a Thai medicinal plant with long tradition of medicinal consumption among menopausal women for rejuvenation and estrogen hormone replacement, on oxidative status in ovariectomized (OVX) mice were determined.

METHODS

The crude extract of PM and its active phytoestrogen, miroestrol (MR), were given to OVX mice. The effect of them on antioxidation enzymes and glutathione (GSH) levels in livers and uteri were examined in OVX mice and compared with the synthetic estradiol hormone.

KEY FINDINGS

Ovariectomy significantly decreased total GSH content, reduced GSH content, and the ratio of GSH to oxidized glutathione (GSSG) in both the livers and the uteri of mice. Moreover, an ovariectomy reduced the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT). The crude extract of PM as well as MR significantly increased levels of GSH, levels of reduced GSH, and the ratio of GSH/GSSG in both the livers and the uteri, while estradiol did not. In addition, the potential of PM and MR to return the activities of GPx, SOD, and CAT to normal levels was noted.

CONCLUSIONS

These observations support using PM and MR as promising alternative medicine candidates for hormone replacement therapy of estradiol because of their ability to improve GSH levels and the activities of antioxidative enzymes, especially in OVX mice.

Protective effects of ulinastatin on acute liver failure induced by lipopolysaccharide/D-galactosamine

BACKGROUND

Although treatment of acute liver failure has been improved significantly recently, the survival rate of acute liver failure is only 5-20%. Therefore, prevention and treatment of acute liver failure are still urgent issues in the field of liver disease.

AIMS

It has been demonstrated that ulinastatin could attenuate acute injury of internal organs from endotoxin. This study evaluates whether ulinastatin can prevent and/or attenuate acute liver failure induced by the combination of lipopolysaccharide and D-galactosamine (LPS/D-gal).

METHODS

Sprague-Dawley rats were employed to induce acute liver failure by injection of LPS/D-gal. The liver function, inflammatory factors, oxidative stress index, and hepatic histopathological alteration were examined in the rats with and without ulinastatin treatment.

RESULTS

In rats treated with LPS/D-gal, there were increases in the levels of ALT and AST in the serum and levels of malondialdehyde and inducible nitric oxide synthase in liver tissues. Moreover, the levels of antioxidants such as superoxide dismutase and glutathione peroxidase were reduced in the liver. Furthermore, inflammatory factors (TNF-alpha and IL-6) and apoptotic enzyme (caspase-3) were increased in the respective serum and liver of rats treated with LPS/D-gal. However, pre-treatment of ulinastatin significantly reversed all of these parameters in the rats that received LPS/D: -gal alone.

CONCLUSIONS

The finding in this study suggests that ulinastatin could be a potential agent for prevention and treatment of acute liver injury induced by LPS/D-gal.

Mechanisms of the cerebral vasodilator actions of isoflavonoids of Gegen on rat isolated basilar artery

ETHNOPHARMACOLOGICAL RELEVANCE

Gegen (root of Pueraria lobata) is used in traditional Chinese medicine for treatment of cardiovascular diseases. In this study, the relaxant actions of three of its isoflavonoids; puerarin, daidzein, and daidzin, were investigated on rat-isolated cerebral basilar artery.

MATERIALS AND METHODS

Rat basilar artery rings were precontracted with 100 nM U46619. Involvement of endothelium-dependent mechanisms was investigated by mechanical removal of the endothelium and inhibitors of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzymes. Adenylyl cyclase- and guanylyl cyclase-dependent pathways were investigated using their respective inhibitors 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536) and 1H-[1,2,4]oxadiazolo [4,3-[alpha]]-quinoxalin-1-one (ODQ). K(+) channels were investigated by pretreatment of the artery rings with various K(+) channel inhibitors, and Ca(2+) channels were investigated in artery rings incubated with Ca(2+)-free buffer and primed with 100 nM U46619 for 5 min prior to adding CaCl(2) to elicit contraction.

RESULTS

Puerarin, daidzein, and daidzin produced concentration-dependent relaxation of the artery rings with concentration that produced 50% inhibition (IC(50)) of 304 ± 49 μM, 20 ± 7 μM, and 140 ± 21 μM, respectively. Removal of the endothelium produced no change on their vasorelaxant responses except the maximum response (I(max)) to puerarin was inhibited by 28%. The NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME; 100 μM) also produced 45% inhibition on the puerarin-induced vasorelaxant response, but not the COX inhibitor flurbiprofen (10 μM). SQ22536 (100 μM) and ODQ (100μM) did not affect the vasodilator responses to puerarin, daidzein and daidzin, but glibenclamide (1μM), tetraethylammonium (TEA, 100mM) or a combination of K(+) channel inhibitors (100nM iberiotoxin+1mM 4-aminopyridine+100 μM barium chloride+1 μM glibenclamide+100mM TEA) reduced their I(max). The contractile response to CaCl(2) was attenuated by 61% and 34% in the presence of daidzein and daidzin, respectively, whereas, puerarin did not significantly affect the contraction.

CONCLUSIONS

The vasorelaxant action of daidzein and daidzin involved opening of K(+) channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. There is no evidence supporting involvement of endothelium-derived relaxing factors (EDRFs) in their actions. In contrast, puerarin produced vasodilatation via an endothelium-dependent mechanism involving nitric oxide production and an endothelium-independent pathway mediated by the opening of K(+) channels. The cerebral vasodilator activities of all these three isoflavonoids may be beneficial to patients with obstructive cerebrovascular diseases.

Expression of p53 during apoptosis induced by D-galactosamine and the protective role of PGE1 in cultured rat hepatocytes

p53 is a critical player in the prevention of tumor development. It can contribute directly to DNA repair and inhibition of angiogenesis and subsequently to the induction of apoptosis. The regulation of p53 expression is mediated by the transcription factor NF-kappaB. This includes regulation of p53 protein stability, control of its subcellular localization and conformational changes that allow activation of the DNA binding activity of p53. Rat hepatocytes were isolated from male Wistar rats following collagenase perfusion of liver. We examined the change in the expression level of p53 by western blotting in hepatocytes and its effect on apoptosis as a response of treatment with D-galactosamine, prostaglandin E1 and/or the Proteosome Inhibitor (PSI). A kinetic study of the extracellular lactate dehydrogenase activity, NF-kappaB activation, induced nitric oxide synthase expression and nitric oxide production was carried out in hepatocytes. The addition of prostaglandin E1 to control and D-galactosamine-treated hepatocytes increased p53 expression in the cytoplasm during 24 h. While the addition of PSI in the absence of prostaglandin E1 decreased p53 expression at 5 mM D-galactosamine. This inhibition is reversed in the presence of prostaglandin E1 at 5 and 40 mM D-galactosamine. The protective action of prostaglandin E1 against the apoptotic effect of D-galactosamine is mediated by NF-kappaB activation, induced nitric oxide synthase and p53 expression.