In vitro and in vivo assessment of cytochrome P450-mediated herb–drug interaction of Ssang-hwa-tang

We have evaluated the herb–drug interaction potential of Ssang-hwa-tang (SHT) mediated by cytochrome P450 (CYP) inhibition/induction. Further, the effects of fermentation on the CYP-mediated herb–drug interaction potential were determined. SHT showed inhibitory activity toward CYP1A2, but not 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, and 3A4 in human liver microsomes. The results of the enzyme kinetic study suggested that the SHT-induced CYP1A2 inhibition is mixed reversible inhibition. The hepatic CYP expression and activity in rats treated with SHT were examined. The expression/activity of CYP2E1 increased as a result of SHT extract treatment (P < 0.005 or P < 0.001, respectively), which raises the possibility that SHT may increase the toxicity of environmental toxicants through the elevation of CYP2E1-mediated metabolic activation. SHT fermentation using Lactobacillus fermentum or Lactobacillus gasseri resulted in attenuation of the SHT-induced CYP1A2 inhibition, but not CYP2E1 induction, suggesting that changes in the chemical composition of SHT through fermentation can affect the inhibition of CYP1A2 activity.     

Regulation of lipid disorders by ethanol extracts from Zingiber zerumbet in high-fat diet-induced rats

The aim of this study was to investigate the antihyperlipidaemic effects of the ethanol extract of Zingiber zerumbet (L) Smith (EEZZ). After being fed a high-fat diet (HFD) for 2 weeks, rats were dosed orally with EEZZ (100, 200 or 300 mg/kg) or fenofibrate (100 mg/kg) once daily for 8 weeks. EEZZ (300 mg/kg/day) produced effects similar to fenofibrate in reducing body weight gain, visceral fat-pad weights and plasma lipid levels. EEZZ caused reductions in hepatic triglyceride and cholesterol content, and lowered hepatic lipid droplet accumulation and the size of epididymal adipocytes. HFD-induced reductions in the hepatic proteins of peroxisome proliferator-activated receptor (PPAR) α, acyl-CoA oxidase (ACO) and cytochrome P450 isoform 4A1 (CYP4A1) were reversed by EEZZ. These results suggest that EEZZ reduced the accumulation of visceral fat and improved hyperlipidaemia in HFD-fed rats by increasing fatty acid oxidation, an effect which is likely to be mediated via up-regulation of hepatic PPARα.     

Quercetin Mitigates Hepatic Insulin Resistance in Rats with Bile Duct Ligation Through Modulation of the STAT3/SOCS3/IRS1 Signaling Pathway

Insulin resistance (IR) and inflammatory mediators are correlated with hepatic fibrosis. Quercetin is a bioflavonoid with well‐known antidiabetic and antifibrotic properties. Bile duct ligation (BDL) is a surgical model performed on animals to produce a murine model in which increased oxidative stress occurs, which results in liver fibrosis. Our study aimed to determine whether quercetin improves hepatic IR as well as hepatic fibrosis in rats experiencing BDL. Male Wistar rats were allocated to four groups according to a random pattern, including a sham group, a sham and quercetin group (30 mg/kg/day), a BDL alone group, and a BDL and quercetin group (30 mg/kg/day). Evaluation of STAT3, SOCS3, IRS1, Rac1, Rac1‐GTP, Sp1, NOX1, HIF‐1α, and ERK1 expression was performed by RT‐PCR along with the western blot analytical technique in liver tissue. The antidiabetic impact of quercetin was associated with reduction in mRNA and expression of protein in STAT3 and SOCS3, along with an increase in IRS1. The antifibrotic effect of quercetin was also determined by downregulation of mRNA or the levels of protein expression of Rac1‐GTP, Rac1, HIF‐1α, NOX1, and Sp1, along with ERK1. Our study indicates that quercetin may improve hepatic fibrosis via inhibiting ROS‐associated inflammation as well as ameliorating hepatic IR by beneficial regulation of the STAT3/SOCS3/IRS1 signaling pathway.     

Smilax China Root Extract Detoxifies Nicotine by Reducing Reactive Oxygen Species and Inducing CYP2A6

Resveratrol has a beneficial effect of lowering reactive oxygen species (ROS) and reduces cellular oxidative stress. We hypothesized that ethanol extract of Smilax china root (EESC) rich in resveratrol (RES) and oxyresveratrol (OXY) could reduce ROS caused by nicotine and promoting nicotine turnover by induction of CYP2A6. The amount of cotinine converted from nicotine was quantified by the direct barbiturate assay method. Expression of CYP2A6 was unregulated by RES, OXY, or EESC, respectively. Pretreatment of RES (50, 100, and 250 μM), OXY (50, 100, and 250 μM), and RES+OXY (50 and 100 μM) inhibited cytotoxicity and ROS production caused by nicotine in a dose‐dependent manner. EESC pretreatment (1.8 mg/mL) increased cell viability by 1.5‐fold higher than the control (nicotine only), and lowered cellular ROS levels. A significant amount of the conversion of nicotine to cotinine was observed in EESC pretreatment by CYP2A6 induction in HepG2 cells. These results suggested that hepatic induction of CYP2A6 and ROS reduction by EESC activate nicotine metabolism and reduce cellular oxidative stress.     

Extract of fermented barley attenuates chronic alcohol induced liver damage by increasing antioxidative activities

Chronic consumption of alcohol leads to liver disorders primarily as hepatosteatosis, and increase of oxidative stress. The abundance of these reactive oxygen species (ROS) is a result of ethanol (ethyl alcohol) oxidation by alcohol dehydrogenase and cytochrome p450 2E1 (CYP2E1). In order to address this problem with natural substance, the high polyphenol content of barley has been numerously cited to provide excellent antioxidative effect. In this study, we investigated the effect of fermented barley extract (FBE) in chronic ethanol fed female Wistar rats. We obtained significant decrease of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the FBE supplemented group. Further examinations revealed that FBE induces substantial improvement in hepatic gene expressions of key anti-oxidative genes, reinforced by its increase of enzymatic activities and subsequent suppression of oxidative stress. Thus we have demonstrated a novel approach for the use of barley as supplements to attenuate chronic alcohol consumption.     

In vivo protective effects of quercetin against sodium fluoride-induced oxidative stress in the hepatic tissue

The protective effects of quercetin against sodium fluoride induced oxidative stress were examined in rat’s liver. Rats were divided into five groups. The first group served as normal group that was treated with standard diet. The second group was intoxicated with sodium fluoride (600 ppm) through drinking water for 1 week. The third, fourth and fifth groups were treated with quercetin at a dose of 10 and 20 mg/kg and vitamin C (as the positive control) at a dose of 10 mg/kg intraperitoneally for 1 week before sodium fluoride intoxication, respectively. After 1 week, activities of superoxide dismutase and catalase, level of reduced glutathione and lipid peroxidation end product were determined in the homogenates of rat liver. The results of the present study suggested that quercetin protects rat liver from sodium fluoride induced oxidative stress, probably via its antioxidant activity.     

Yerba-mate (Ilex paraguariensis) extract prevents ethanol-induced liver injury in rats

Ethanol metabolism-associated oxidative stress contributes to the pathogenesis of alcoholic liver disease. We examined the effect of a Mate tea extract on ethanol-induced liver injury in vitro and in vivo models. Isolated hepatocytes were incubated with ethanol. An extract of Yerba-Mate tea (EMT) was added to the cultures simultaneously with ethanol. EMT treatment suppressed the ethanol-induced increase in cell death by inhibiting cytochrome p450 2E1 (CYP2E1) activity, which is related to the production of reactive oxygen species. Furthermore, we examined the effects of EMT on serum transaminase activity, and the progression of liver fibrosis in rats treated with ethanol and CCl₄. Rats were fed a diet that included 0.005% or 0.02% EMT or no EMT. For a period of 3 weeks, the animals were provided drinking water containing 5% ethanol and were also treated with carbon tetrachloride (CCl₄) (0.1 ml/kg of body weight). EMT treatment suppressed plasma ALT and AST activities in the ethanol- and CCl₄-treated rats. EMT treatment also decreased CYP2E1 expression and increased ADH expression in the ethanol- and CCl₄-treated rats. EMT treatment fully protected the rats against ethanol- and CCl₄-induced liver injury. These results suggest that EMT may serve as a candidate for preventing ethanol-induced liver injury.     

Effects of taurine on hepatic lipid metabolism and anti-inflammation in chronic alcohol-fed rats

The effects of taurine (Tau) in regulation of lipid metabolism and decreasing inflammation in chronic alcohol-fed rats was investigated. Rats were randomly divided into three groups: (1) isocaloric solution; (2) 3 g alcohol/kg BW/day; (3) 3 g alcohol/kg BW/day + 1 g Tau/kg BW/day for 6 weeks. Liver size and serum/liver lipids of alcohol-fed rats were decreased (p < 0.05) by Tau supplementation, but daily fecal lipid/bile acid outputs were increased (p < 0.05). Regarding de novo lipogenesis, Tau downregulated (p < 0.05) fatty-acid biosynthesis and upregulated (p < 0.05) cholesterol metabolism (CYP7A1) and energy expenditure (PPAR-α). Serum AST and ALT, and hepatic TNF-α levels and MMP-9 activity of alcohol-fed rats were decreased (p < 0.05) by Tau supplementation which may be related to the maintenance of higher (p < 0.05) antioxidant levels (lower thiobarbituric-acid-reactive-substances values and higher trolox equivalent antioxidant capacity) in serum and livers. Our study indicates that Tau downregulates lipogenesis, oxidative stress, and inflammation in chronic alcohol-fed rats.     

Protective effect of white tea extract against acute oxidative injury caused by adriamycin in different tissues

Adriamycin (ADR) is an anticancer agent that increases oxidative stress in cells. We evaluated the protective effect of the long term consumption of white tea at two different doses against this drug. For this purpose rats were given distilled water (controls), 0.15 mg (Dose 1) or 0.45 mg (Dose 2) of solid tea extract/kg body weight for 12 months. All the animals received an injection of ADR, except half of the control group, which were given an injection of saline solution. This gave four experimental groups: Control (C), C + ADR, Dose 1 + ADR, and Dose 2 + ADR. The antioxidant activity (in liver, heart and brain microsomes) was analysed. White tea consumption for 12 months, at a non-pharmacological dose, reversed the oxidative damage caused by ADR, on both protein and lipid levels in all three organs. The heart recovered its antioxidant activity only at the highest dose of tea.     

Plant flavonol quercetin and isoflavone biochanin A differentially induce protection against oxidative stress and inflammation in ARPE-19 cells

In this work, differential ability of plant flavonol quercetin and plant isoflavone biochanin A to modulate oxidative stress and inhibit inflammation-related responses was investigated using human retinal pigment epithelial cells (RPE) at gene expression level. Quercetin protected cells from oxidative stress-induced cell death, whereas biochanin A had no statistically significant protective effects. Quercetin reduced the expression of cytokines IL-6 and IL-1?? in cells treated with H₂O₂, and expression levels of Nrf2 and HO-1 were increased by quercetin treatment suggesting protective function against oxidative stress. Our data indicate that quercetin may protect cells by inhibiting the production of pro-inflammatory factors such as IL-6, and by inducing the expression of ROS-catalyzing phase II proteins such as HO-1. Therefore, plant extracts rich in flavonol quercetin may be an interesting resource for functional food products and other foods targeted for reduced risks of age-related macular degeneration.     

Diallyl-disulphide is the effective ingredient of garlic oil that protects primary human osteoblasts from damage due to cigarette smoke

Cigarette consumption negatively affects bone-matter and -stability, partially due to increased oxidative stress. Garlic has been shown to have anti-oxidative properties. Therefore, the intention was to investigate whether garlic oil blend (GOB) reduces cellular damage in human osteoblasts exposed to cigarette smoke medium (CSM). Formation of ROS was rapidly induced in osteoblasts exposed to CSM and their viability decreased in a concentration- and time-dependent manner (EC₅₀ ≈ 0.75 OD₃₂₀). Co-, pre- and post-incubation with GOB significantly improved their viability. Testing both major components of GOB, diallyl-sulphide (DAS) and diallyl-disulphide (DADS), showed that DADS is more efficient. DADS markedly induced the expression of the anti-oxidative enzyme haeme-oxygenase (HO)-1. The HO-1 inhibitor zinc-protoporphyrin reduced the protective effect of all three substances. Summarizing, CSM damages osteoblasts by accumulation of ROS. GOB and especially DADS reduce this damage by scavenging the radicals and by up-regulating HO-1. Thus, a garlic rich diet or dietary supplementation with DADS might improve bone-matter, -stability and even fracture healing in smokers.     

Cytoprotective effects of pu-erh tea on hepatotoxicity in vitro and in vivo induced by tert-butyl-hydroperoxide

The in vitro and in vivo protective effects of water extract of pu-erh tea (WEPT) on tert-butyl-hydroperoxide (t-BHP)-induced oxidative damage in hepatocytes of HepG2 cells and in rat livers were investigated. After treatment with 200 μg/ml of samples, the survival rate of HepG2 cells induced by t-BHP increased. WEPT concentration-dependently inhibited reactive oxygen species (ROS) generation in HepG2 cells in response to the oxidative challenge induced by t-BHP. Administration of WEPT (0.2, 0.5 and 1.0 g/kg of body weigh) to rats for 56 consecutive days before a single dose of t-BHP (0.5 mmol/kg, i.p.) exhibited a significant (p < 0.01) protective effect by lowering serum levels of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), as well as reducing the formation of malondialdehyde. Taken together, these results demonstrate that WEPT is able to protect against hepatic damage in vitro and in vivo, suggesting that the drinking of pu-erh tea may protect liver tissue from oxidative damage.     

Prevention of ethanol-induced hepatotoxicity by fermented Curcuma longa L. in C57BL/6 mice

The protective effect of fermented Curcuma longa L. (FC) was investigated in male C57BL/6 mice under ethanol-induced oxidative stress. Ethanol markedly elevated levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in mice. However, mice receiving FC prior to ethanol treatment did not display hepatotoxicity as evidenced by the significant reductions of AST and ALT activities. When compared to the ethanol-alone treated group, FC group exhibited a significant decrease in cytochrome P-450 2E1 (CYP2E1) activity, an enzyme associated with oxidative stress. Indicators of the hepatic antioxidant defense system, such as levels of superoxide dismutase, catalase, glutathione reductase and glutathione were also increased in FC-pretreated mice. The amelioration of malondialdehyde was indicative of the protective effect of FC against liver damage mediated by ethanol. These results suggest that FC could be a candidate used for the prevention against alcoholic liver diseases by the alleviation of oxidative stress via suppressing CYP2E1.     

Effects of quercetin metabolites on the enhancing effect of β-carotene on DNA damage and cytochrome P1A1/2 expression in benzo[a]pyrene-exposed A549 cells

A549 cells were pre-incubated with β-carotene (BC) alone or in combination with quercetin or three major quercetin metabolites in human plasma, quercetin 3-glucuronide (Q3G), quercetin 3′-sulphate (Q3′S) and isorhamnetin, followed by incubation with benzo[a]pyrene (BaP), to investigate the effects of these compounds on the BaP-induced harmful effects of BC. All the quercetin metabolites at 10 μM inhibited BaP + BC-induced cell death. Q3′S, Q3G and isorhamnetin also significantly decreased BaP ± BC-induced DNA damage by 64%, 60% and 24%, respectively. In a similar order, these compounds suppressed BaP + BC-induced cytochrome P450 (CYP)1A1/1A2 expression by 10–50%. Q3G and Q3′S significantly decreased the intracellular reactive oxygen species formation induced by BaP + BC; however, Q3G had the best effect on decreasing the loss of BC induced by Fe/NTA. The combined effects of quercetin metabolites were additive. This study indicates that quercetin metabolites decrease the BaP-induced harmful effect of β-carotene in A549 cells by downregulating the expression of CYP1A1/1A2, at least in part.     

Chinese bayberry fruit extract alleviates oxidative stress and prevents 1,2-dimethylhydrazine-induced aberrant crypt foci development in rat colon carcinogenesis

The effects of Chinese bayberry fruit extract (CBFE) ingestion on hepatic and colonic oxidative stress and 1,2-dimethylhydrazine (DMH)-induced intestinal aberrant crypt foci (ACF) development in rats were investigated. Rats were administered DMH (35 mg/kg body weight) and were supplemented with CBFE (50 or 500 mg/kg body weight every day) for 16 weeks. Results showed that DMH consumption induced intestinal ACF development and adenoma or adenocarcinoma formation, which were significantly reduced with CBFE supplement. The CBFE treatments increased reduced glutathione levels and activities of superoxide dismutase, catalase and glutathione reductase, in both hepatic and colonic tissues; however, the activities of glutathione-S-transferase and glutathione peroxidase were inhibited. These results indicate that CBFE, rich in phenolic compounds, effectively inhibits DMH-induced ACF and colonic tumour development by alleviating oxidative stress.     

Protective effects of fermented onion juice containing higher amount of querectin aglycone against oxidative stress by 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) treatment in Sprague–Dawley rats

It has been reported on beneficial effects of onion extracts containing a large amount of quercetin glucosides for several decades. This study was performed to investigate antioxidative and hepatoprotective effects of fermented onion (Allium cepa L.) extracts containing higher amount of quercetin aglycone (FOQ) against oxidative stress by 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) treatment in rats. RP-HPLC analysis elucidated that the fermented onions contain larger amount of quercetin aglycone than that of fresh onions, and the content of quercetin aglycone in 1.0 kg of fresh and fermented onion pickles was 261.34 ± 19.47 and 360.25 ± 27.32 mg, respectively. In vitro free radical scavenging assay showed potently radical-quenching ability of FOQ against reactive oxygen species (ROS) such as hydroxyl, superoxide, and carbon-centered radical using electron spin resonance (ESR) spectroscopy. Biological parameters in plasma and liver tissue were evaluated with 36 healthy Sprague–Dawley rats in the experimental groups (n = 6); control (basal diet), AAPH treated, quercetin aglycone treated, ascorbate-AAPH treated, quercetin aglycone-AAPH treated and FOQ-AAPH treated group. The results revealed that quercetin aglycone or FOQ intakes could increase the level of glutathione (GSH), enzymatic activity of glutathione reductase (GSSG-R), and catalase (CAT), but could decrease the level of glutamate oxaloacetic transaminase (GOT), glutamate pyruvate transaminase (GPT), thiobarbituric acid reactive substance (TBARS) production with the abnormal levels caused by AAPH induced oxidative stress. Moreover, histological study for central vein (CV) area of hepatic lobule was illustrated that cytoplasmic phase near the CV in the qurecetin and FOQ pretreated before AAPH injection could be maintained with normal morphology like that of the control. The present study illustrated that the fermented onion extracts containing larger amount of quercetin aglycone (FOQ) have antioxidative activities against AAPH-induced carbon-centered radical, and its activity can present the protective effect against hepatic damage by oxidative stress similar with the ability of ascorbate (vitamin C).     

Hepatoprotection using sweet orange peel and its bioactive compound,hesperidin, for CCl4-induced liver injury in vivo

The hepatoprotective effect of water extracts of sweet orange (Citrus sinensis) peel (WESP) and its biological compound, hesperidin (HD), on oxidative stress in vivo, were investigated. HD was the major compounds among the ten compounds identified using HPLC-DAD and HPLC-MS/MS analysis. Oral administration of WESP to rats at 10 and 100 mg/kg bw for 28 consecutive days before a single dose of CCl₄ (2 ml/kg bw) demonstrates a significant protective effect by lowering the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and by improving the histological architecture of the rat liver. WESP attenuated oxidative stress by increasing the content of hepatic glutathione (GSH), and by a dramatic increase in the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). WESP induced a significant CYP2E1 activity, which suggests that WESP may be a substrate of CYP2E1. WESP at a dose of 1.0 mg/kg bw and HD at 0.1 mg/kg bw did not sustain the protective effect against oxidative stress, in vivo. This study demonstrated that citrus peel protects rat liver from CCl₄-induced injury by attenuating hepatic oxidative stress, which suggests that WESP can be used as a therapeutic antihepatotoxic agent for the treatment of hepatic injury.     

Increased exposure of vitamin A by Chrysanthemum morifolium Ramat extract in rat was not via induction of CYP1A1, CYP1A2, and CYP2B1

The aim of this study was to investigate the effect of Chrysanthemum morifolium Ramat (CM) extract on the pharmacokinetics of retinol and activities of cytochrome P450s (CYP450s) related to retinoid metabolism. Rats were treated with CM extract for 15 d. Plasma concentrations of retinol were measured following oral administration of retinol (45 mg/kg). Basal levels of retinol and retinoic acid in serum and liver were also measured. 7-Ethoxyresorufin-O-deethylase activity, phenacetin-O-deethylase activity, and 7-pentoxyresorufin-O-deethylase activities were used to assay the activities of CYP1A1, CYP1A2, and CYP2B1 in hepatic microsomes of rats, respectively. Protein expressions of the 3 CYP450s were measured by western blot. Our studies demonstrated that CM extract dose-dependently increased basal level of retinol in serum. In pharmacokinetic experiment, CM extract dose-dependently increased plasma concentrations of retinol after oral administration of retinol to rats treated with CM extract. But activities and expressions of CYP1A1, CYP1A2, and CYP2B1 in hepatic microsomes of rats were also induced by CM extract.     

Antiobese and hypocholesterolaemic effects of an Adenophora triphylla extract in HepG2 cells and high fat diet-induced obese mice

The ethyl acetate extract from Adenophora triphylla root (ATea) had strong antioxidant effect. We hypothesised that a high fat (HF) diet might induce oxidative stress and so, dietary antioxidant may have beneficial effects on hypercholesterolaemia, but the underlying mechanisms involved are not fully understood. To test this hypothesis, C57BL/6 mice were fed with HF diet for 9 weeks. In the last 4 weeks, the HF diet was supplemented with 0, 25 or 75 mg/kg ATea. ATea decreased body weight gain and both ATea doses significantly reduced the plasma and hepatic cholesterol levels of the obese mice. Analysis of the hepatic expression of proteins known to play important roles in cholesterol metabolism indicated that ATea significantly enhanced low density lipoprotein receptor (LDL receptor) and cholesterol 7α-hydroxylase (CYP7A1) expression but inhibited the 3-hydroxy-3-methylglutaryl–CoA reductase (HMG–CoA reductase) expression in HepG2 cells and mice. No mutagenic activity was observed at high doses of ATea.     

Effects of flavonoids on CYP1 expression in RL95-2 endometrial carcinoma cells

RL95-2 endometrial cancer cells were used to study cytochrome P450-mediated chemopreventative mechanisms of four flavonoids found in foods. To investigate enzymatic CYP1 inhibition, intact cells were induced with benzo(a)pyrene or 2,3,7,8-tetrachlorodibenzo-p-dioxin. Quercetin, kaempferol and myricetin inhibited CYP1 activity dose-dependently with IC₅₀s ranging from 2.2 to 4 μM; while amentoflavone was inactive. Further experiments were designed to determine if flavonoids also interacted with the AhR or caused a decrease in CYP1 protein or mRNA expression. CYP1A1 protein expression was inhibited in cells co-treated with TCDD and quercetin, kaempferol or myricetin compared with TCDD alone, but amentoflavone was ineffective. Relatively higher (∼7-fold) basal levels of CYP1B1 protein were not significantly affected by flavonoid treatments. In general, at the message level significant inhibition of induced CYP1A1 or CYP1B1 was not detected following flavonoid cotreatment. Despite the common inhibitory effects of quercetin, kaempferol, and myricetin on induced CYP1A1-dependent activity and protein expression, the mechanisms of CYP1 inhibition in this cell line are complex and dependent on the CYP gene, AhR inducer and the flavonoid.