Integrative transcriptome and whole-genome bisulfite sequencing analyses of a temperature-sensitive albino tea plant cultivar.

Green tea made from albino buds and leaves has a strong umami taste and aroma. The cultivar 'Zhonghuang 2' (ZH2, Camellia sinensis) is a natural mutant with young shoots that are yellow in spring and green or yellow-green in summer. However, the mechanism of leaf color change remains unclear. Here, we found that young shoots of ZH2 were yellow at low temperature (LT) and green at high temperature (HT), indicating that ZH2 is a temperature-sensitive cultivar. Transmission electron microscopy analysis showed that the grana in the chloroplasts of young shoots grown at LT were poorly stacked, which caused a lack of photoreactions and chlorophyll. RNA-seq results showed 1279 genes differentially expressed in the young shoots grown at LT compared with those at HT, including genes related to cytochrome synthesis, chloroplast development, photosynthesis, and DNA methylation. A whole-genome bisulfite sequencing assay revealed that the dynamics of DNA methylation levels in the CG, CHG, and CHH contexts decreased under LT, and the change was most obvious in the CHH context. Furthermore, 72 genes showed significant changes in both expression and DNA methylation levels, and most of them were related to cytochrome synthesis, chloroplast development, photosynthesis, transcription factors, and signaling pathways. These results demonstrate that DNA methylation is involved in the LT-regulated albino processes of ZH2. Changes in DNA methylation levels were associated with changes in gene expression levels, affecting the structure and function of chloroplasts, which may have a phenotypic impact on shoot and leaf color.

Vitamin D modulation of brain-gut-virome disorder caused by polystyrene nanoplastics exposure in zebrafish (Danio rerio).

BACKGROUND: Many studies have investigated how nanoplastics (NPs) exposure mediates nerve and intestinal toxicity through a dysregulated brain-gut axis interaction, but there are few studies aimed at alleviating those effects. To determine whether and how vitamin D can impact that toxicity, fish were supplemented with a vitamin D-low diet and vitamin D-high diet. RESULTS: Transmission electron microscopy (TEM) showed that polystyrene nanoplastics (PS-NPs) accumulated in zebrafish brain and intestine, resulting in brain blood-brain barrier basement membrane damage and the vacuolization of intestinal goblet cells and mitochondria. A high concentration of vitamin D reduced the accumulation of PS-NPs in zebrafish brain tissues by 20% and intestinal tissues by 58.8% and 52.2%, respectively, and alleviated the pathological damage induced by PS-NPs. Adequate vitamin D significantly increased the content of serotonin (5-HT) and reduced the anxiety-like behavior of zebrafish caused by PS-NPs exposure. Virus metagenome showed that PS-NPs exposure affected the composition and abundance of zebrafish intestinal viruses. Differentially expressed viruses in the vitamin D-low and vitamin D-high group affected the secretion of brain neurotransmitters in zebrafish. Virus AF191073 was negatively correlated with neurotransmitter 5-HT, whereas KT319643 was positively correlated with malondialdehyde (MDA) content and the expression of cytochrome 1a1 (cyp1a1) and cytochrome 1b1 (cyp1b1) in the intestine. This suggests that AF191073 and KT319643 may be key viruses that mediate the vitamin D reduction in neurotoxicity and immunotoxicity induced by PS-NPs. CONCLUSION: Vitamin D can alleviate neurotoxicity and immunotoxicity induced by PS-NPs exposure by directionally altering the gut virome. These findings highlight the potential of vitamin D to alleviate the brain-gut-virome disorder caused by PS-NPs exposure and suggest potential therapeutic strategies to reduce the risk of NPs toxicity in aquaculture, that is, adding adequate vitamin D to diet. Video Abstract.

Developmentally regulated mitochondrial biogenesis and cell death competence in maize pollen.

BACKGROUND: Cytoplasmic male sterility (CMS) is a maternally inherited failure to produce functional pollen that most commonly results from expression of novel, chimeric mitochondrial genes. In Zea mays, cytoplasmic male sterility type S (CMS-S) is characterized by the collapse of immature, bi-cellular pollen. Molecular and cellular features of developing CMS-S and normal (N) cytoplasm pollen were compared to determine the role of mitochondria in these differing developmental fates. RESULTS: Terminal deoxynucleotidyl transferase dUTP nick end labeling revealed both chromatin and nuclear fragmentation in the collapsed CMS-S pollen, demonstrating a programmed cell death (PCD) event sharing morphological features with mitochondria-signaled apoptosis in animals. Maize plants expressing mitochondria-targeted green fluorescent protein (GFP) demonstrated dynamic changes in mitochondrial morphology and association with actin filaments through the course of N-cytoplasm pollen development, whereas mitochondrial targeting of GFP was lost and actin filaments were disorganized in developing CMS-S pollen. Immunoblotting revealed significant developmental regulation of mitochondrial biogenesis in both CMS-S and N mito-types. Nuclear and mitochondrial genome encoded components of the cytochrome respiratory pathway and ATP synthase were of low abundance at the microspore stage, but microspores accumulated abundant nuclear-encoded alternative oxidase (AOX). Cytochrome pathway and ATP synthase components accumulated whereas AOX levels declined during the maturation of N bi-cellular pollen. Increased abundance of cytochrome pathway components and declining AOX also characterized collapsed CMS-S pollen. The accumulation and robust RNA editing of mitochondrial transcripts implicated translational or post-translational control for the developmentally regulated accumulation of mitochondria-encoded proteins in both mito-types. CONCLUSIONS: CMS-S pollen collapse is a PCD event coincident with developmentally programmed mitochondrial events including the accumulation of mitochondrial respiratory proteins and declining protection against mitochondrial generation of reactive oxygen species.

Bioenergetics and Reactive Nitrogen Species in Bacteria.

The production of reactive nitrogen species (RNS) by the innate immune system is part of the host's defense against invading pathogenic bacteria. In this review, we summarize recent studies on the molecular basis of the effects of nitric oxide and peroxynitrite on microbial respiration and energy conservation. We discuss possible molecular mechanisms underlying RNS resistance in bacteria mediated by unique respiratory oxygen reductases, the mycobacterial bcc-aa3 supercomplex, and bd-type cytochromes. A complete picture of the impact of RNS on microbial bioenergetics is not yet available. However, this research area is developing very rapidly, and the knowledge gained should help us develop new methods of treating infectious diseases.

Coupling methanogenesis with iron reduction by acetotrophic Methanosarcina mazei zm-15.

Application of ferric iron is conventionally considered to inhibit methanogenesis in anoxic environments. Here we show that Methanosarcina mazei zm-15, a strain isolated from the natural wetland of Tibetan plateau, is capable of Fe(III) reduction, which significantly promotes its growth and methanogenesis. We grew Ms. mazei zm-15 in a medium containing acetate supplemented with Fe(III) in ferric citrate or ferrihydrite and to some cultures anthraquinone-2,6-disulfonate (AQDS) was applied as an electron shuttle. The reduction of Fe(III) species occurred immediately. Ferric citrate was more readily reduced than ferrihydrite. The X-ray diffraction spectra analysis showed the formation of magnetite from ferrihydrite and amorphous reduced products from ferrihydrite plus AQDS. The analysis of protein contents revealed that Fe(III) reduction contributed 36%-46% of the cell growth. The growth yield, estimated as protein increment per acetate consumed for Fe(III) reduction, increased by 20- to 30-fold compared with methanogenesis, which is in consistence with the difference in free energy available by Fe(III) reduction relative to methanogenesis. We propose that the outer-surface multiheme c-type cytochrome predicted from Ms. mazei zm-15 genome serves as the terminal reductase with the energy-converting hydrogenase and F420 H2 dehydrogenase involved in electron transport chain for Fe(III) reduction. The findings shed a light to better understand the ecophysiology of Methanosarcina in anaerobic environments.

Differential gene content and gene expression for bacterial evolution and speciation of Shewanella in terms of biosynthesis of heme and heme-requiring proteins.

BACKGROUND: Most species of Shewanella harbor two ferrochelatase paralogues for the biosynthesis of c-type cytochromes, which are crucial for their respiratory versatility. In our previous study of the Shewanella loihica PV-4 strain, we found that the disruption of hemH1 but not hemH2 resulted in a significant accumulation of extracellular protoporphyrin IX (PPIX), but it is different in Shewanella oneidensis MR-1. Hence, the function and transcriptional regulation of two ferrochelatase genes, hemH1 and hemH2, are investigated in S. oneidensis MR-1. RESULT: In the present study, deletion of either hemH1 or hemH2 in S. oneidensis MR-1 did not lead to overproduction of extracellular protoporphyrin IX (PPIX) as previously described in the hemH1 mutants of S. loihica PV-4. Moreover, supplement of exogenous hemins made it possible to generate the hemH1 and hemH2 double mutant in MR-1, but not in PV-4. Under aerobic condition, exogenous hemins were required for the growth of MR-1ΔhemH1ΔhemH2, which also overproduced extracellular PPIX. These results suggest that heme is essential for aerobic growth of Shewanella species and MR-1 could also uptake hemin for biosynthesis of essential cytochrome(s) and respiration. Besides, the exogenous hemin mediated CymA cytochrome maturation and the cellular KatB catalase activity. Both hemH paralogues were transcribed in wild-type MR-1, and the hemH2 transcription was remarkably up-regulated in MR-1ΔhemH1 mutant to compensate for the loss of hemH1. The periplasmic glutathione peroxidase gene pgpD, located in the same operon with hemH2, and a large gene cluster coding for iron, heme (hemin) uptake systems are absent in the PV-4 genome. CONCLUSION: Our results indicate that the genetic divergence in gene content and gene expression between these Shewanella species, accounting for the phenotypic difference described here, might be due to their speciation and adaptation to the specific habitats (iron-rich deep-sea vent versus iron-poor freshwater) in which they evolved and the generated mutants could potentially be utilized for commercial production of PPIX.

Repeated evolution of cytochrome P450-mediated spiroketal steroid biosynthesis in plants.

Diosgenin is a spiroketal steroidal natural product extracted from plants and used as the single most important precursor for the world steroid hormone industry. The sporadic occurrences of diosgenin in distantly related plants imply possible independent biosynthetic origins. The characteristic 5,6-spiroketal moiety in diosgenin is reminiscent of the spiroketal moiety present in anthelmintic avermectins isolated from actinomycete bacteria. How plants gained the ability to biosynthesize spiroketal natural products is unknown. Here, we report the diosgenin-biosynthetic pathways in himalayan paris (Paris polyphylla), a monocot medicinal plant with hemostatic and antibacterial properties, and fenugreek (Trigonella foenum-graecum), an eudicot culinary herb plant commonly used as a galactagogue. Both plants have independently recruited pairs of cytochromes P450 that catalyze oxidative 5,6-spiroketalization of cholesterol to produce diosgenin, with evolutionary progenitors traced to conserved phytohormone metabolism. This study paves the way for engineering the production of diosgenin and derived analogs in heterologous hosts.

Transcriptome Profiling of Two Ornamental and Medicinal Papaver Herbs.

The Papaver spp. (Papaver rhoeas (Corn poppy) and Papaver nudicaule (Iceland poppy)) genera are ornamental and medicinal plants that are used for the isolation of alkaloid drugs. In this study, we generated 700 Mb of transcriptome sequences with the PacBio platform. They were assembled into 120,926 contigs, and 1185 (82.2%) of the benchmarking universal single-copy orthologs (BUSCO) core genes were completely present in our assembled transcriptome. Furthermore, using 128 Gb of Illumina sequences, the transcript expression was assessed at three stages of Papaver plant development (30, 60, and 90 days), from which we identified 137 differentially expressed transcripts. Furthermore, three co-occurrence heat maps are generated from 51 different plant genomes along with the Papaver transcriptome, i.e., secondary metabolite biosynthesis, isoquinoline alkaloid biosynthesis (BIA) pathway, and cytochrome. Sixty-nine transcripts in the BIA pathway along with 22 different alkaloids (quantified with LC-QTOF-MS/MS) were mapped into the BIA KEGG map (map00950). Finally, we identified 39 full-length cytochrome transcripts and compared them with other genomes. Collectively, this transcriptome data, along with the expression and quantitative metabolite profiles, provides an initial recording of secondary metabolites and their expression related to Papaver plant development. Moreover, these profiles could help to further detail the functional characterization of the various secondary metabolite biosynthesis and Papaver plant development associated problems.

The Eponymous Cofactors in Cytochrome P460s from Ammonia-Oxidizing Bacteria Are Iron Porphyrinoids Whose Macrocycles Are Dibasic.

The enzymes hydroxylamine oxidoreductase and cytochrome (cyt) P460 contain related unconventional "heme P460" cofactors. These cofactors are unusual in their inclusion of nonstandard cross-links between amino acid side chains and the heme macrocycle. Mutagenesis studies performed on the Nitrosomonas europaea cyt P460 that remove its lysine-heme cross-link show that the cross-link is key to defining the spectroscopic properties and kinetic competence of the enzyme. However, exactly how this cross-link confers these features remains unclear. Here we report the 1.45 Å crystal structure of cyt P460 from Nitrosomonas sp. AL212 and conclude that the cross-link does not lead to a change in hybridization of the heme carbon participating in the cross-link but rather enforces structural distortions to the macrocycle away from planarity. Time-dependent density functional theory coupled to experimental structural and spectroscopic analysis suggest that this geometric distortion is sufficient to define the spectroscopic properties of the heme P460 cofactor and provide clues toward establishing a relationship between heme P460 electronic structure and function.

Ephedra water decoction and cough tablets containing ephedra and liquorice induce CYP1A2 but not CYP2E1 hepatic enzymes in rats.

1. Ephedra water decoction (EWD) and cough tablets containing ephedra and liquorice (maxing cough tablets, MXCT) have been widely used in the treatment of asthma. In the clinic, EWD and MXCT may be prescribed with theophylline, one of the most popular antiasthmatic drugs. CYP1A2 and CYP2E1 are mainly involved in the oxidative metabolism of theophylline in human liver. Drug interactions involving the cytochrome P450 (CYP) isoforms generally are of two types: enzyme induction or enzyme inhibition. Enzyme inhibition reduces metabolism, whereas induction can increase it. 2. To evaluate the pretreatment effect of EWD and MXCT on CYP1A2 and CYP2E1, CYP1A2 and CYP2E1 activity, the protein expression and mRNA expression levels were determined. After pretreatment with EWD or MXCT, the enzyme activity, mRNA expression and protein expression of CYP1A2 were increased significantly (p < 0.05), but enzyme activity of CYP2E1 did not change compared with the control. 3. It was demonstrated that EWD or MXCT pretreatment obviously induced CYP1A2, therefore, in patients taking EWD or MXCT, possible CYP-induced drug interaction should be noted to decrease the risk of therapeutic failure or adverse effects resulting from the use of additional therapeutic agents.

Monooxygenase system in Guerin's carcinoma of rats under conditions of ω-3 polyunsaturated fatty acids administration.

The aim of the study was to determine the variations of function in components of monooxygenase system (MOS) of rat Guerin's carcinoma under ω-3 polyunsaturated fatty acids (PUFAs) administration. The activity of Guerin's carcinoma microsomal NADH-cytochrome b5 reductase, the content and the rate of cytochrome b5 oxidation-reduction, the content and the rate of cytochrome Р450 oxidation-reduction have been investigated in rats with tumor under conditions of ω-3 PUFAs administration. ω-3 PUFAs supplementation before and after transplantation of Guerin's carcinoma resulted in the increase of NADH-cytochrome b5 reductase activity and decrease of cytochrome b5 level in the Guerin's carcinoma microsomal fraction in the logarithmic phases of carcinogenesis as compared to the tumor-bearing rats. Increased activity of NADH-cytochrome b5 reductase facilitates higher electron flow in redox-chain of MOS. Under decreased cytochrome b5 levels the electrons are transferred to oxygen, which leads to heightened generation of superoxide (O2•-) in comparison to control. It was shown, that the decrease of cytochrome P450 level in the Guerin's carcinoma microsomal fraction in the logarithmic phases of oncogenesis under ω-3 PUFAs administration may be associated with its transition into an inactive form ­ cytochrome P420. This decrease in cytochrome P450 coincides with increased generation of superoxide by MOS oxygenase chain.

Enicostemma littorale prevents tumor formation in 7,12-dimethylbenz(a)anthracene-induced hamster buccal pouch carcinogenesis.

Oral cancer is one of the most common malignancies worldwide, and India has recorded the highest annual incidence of oral cancer in comparison with other countries. Altered lipid peroxidation and antioxidant status along with defect in detoxification cascade have been implicated in the pathogenesis of several cancers including oral cancer. The aim of this study was to investigate the chemopreventive potential of ethanolic extract of Enicostemma littorale leaves (ElELet) in 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Oral tumor was developed in the buccal pouches of male golden Syrian hamsters by painting with 0.5% DMBA three times a week for 14 weeks. We observed 100% tumor formation with increase in tumor volume and tumor burden in the hamsters treated with DMBA alone. Imbalance in phase I (cytochrome P450 and cytochrome b5) and phase II (glutathione reductase, glutathione-S-transferase, glutathione, and Deoxythymidine-diaphorase (DT)-diaphorase) detoxification agents and lipid peroxidation by-products (thiobarbituric acid reactive substances) and antioxidant (superoxide dismutase, catalase, glutathione peroxidase, and vitamins E and C) status was noticed in hamsters treated with DMBA alone. Oral administration of ElELet at a dose of 250 mg/kg body weight to hamsters treated with DMBA significantly prevented both precancerous and cancerous lesions in the oral cavity. ElELet modulated the status of phase I and II detoxification agents and antioxidants in favor of the suppression of oral carcinogenesis. This study thus suggests that E. littorale might have inhibited the oral carcinogenesis in DMBA-treated hamsters through its antioxidant potential. The present findings are also substantiated by histological studies during DMBA-induced oral carcinogenesis.

Effects of Ziziphus jujuba fruit extracts on cytochrome P450 (CYP1A2) activity in rats.

Drug-drug interactions have become a serious problem in the clinic, since plant-based medicines are extensively used. The present study investigated the effects of Ziziphus jujuba fruit (ZJ) extract on the pharmacokinetics of phenacetin, a typical substrate of a cytochrome P450 enzyme CYP 1A2, in rats. The rats were pretreated with the water extract (1.0 g · kg(-1)) or the ethanolic extract (3.6 g · kg(-1)) of ZJ for 10 days, and the pharmacokinetics of phenacetin was investigated after intravenous administration. In an in vitro assay, acetaminophen formation in the hepatic microsomes of ZJ-treated rats was investigated to assess CYP1A2 activity. Our results demonstrated that the treatment with the water and ethanolic extracts of ZJ decreased the plasma concentration of phenacetin and increased the plasma concentration of acetaminophen, resulting in a 43.2% and 15.5% reduction in the AUC0-120 of phenacetin, respectively, and a 53.2% and 64.9% increase in the AUC0-120 of acetaminophen, respectively after intravenous administration. The water or ethanolic extract of ZJ significantly increased the clearance of phenacetin and acetaminophen formation in hepatic microsomes. In conclusion, ZJ extracts displayed effects on the pharmacokinetics of phenacetin and increased the CYP1A2 activity in rats. Therefore, precaution on drug-drug interactions should be taken when ZJ is co-administered with drugs metabolized by CYP1A2, which may result in decreased concentrations of these drugs.

Effects of suberoylanilide hydroxamic acid on rat cytochrome P450 enzyme activities.

Vorinostat (suberoylanilide hydroxamic acid, SAHA) is the first approved histone deacetylase (HDAC) inhibitor for the treatment of cutaneous T-cell lymphoma after progressive disease following two systemic therapies. The rats were randomly divided into SAHA groups (low, medium and high dosage) and control group. The SAHA group rats were given 12.3, 24.5, and 49 mg/kg SAHA, respectively, by continuous intragastric administration for 7 days. The influence of SAHA on the activities of CYP450 isoforms CYP2B6, CYP1A2, CYP2C19, CYP2D6 and CYP2C9 were evaluated by cocktail method, they were responsed by the changes of pharmacokinetic parameters of bupropion, phenacetin, tolbutamide, metroprolol and omeprazole. The five probe drugs were given to rats through intragastric administration, and the plasma concentration were determined by UPLC-MS/MS. The result of SAHA group compared to control group, there were statistical pharmacokinetics difference for bupropion, phenacetin, tolbutamide and metroprolol. Continuous intragastric administration for 7 days may induce the activities of CYP2C19 of rats, inhibit CYP1A2 and slightly inhibit CYP2B6 and CYP2D6 of rats. This may give advising for reasonable drug use after co-used with SAHA. The results indicated that drug co-administrated with SAHA may need dose adjustment. Furthermore, continuous intragastric administration of SAHA for 7 days, liver cell damaged, causing liver cell edema, in liver metabolism process.

Benzoic acid derivatives with improved antifungal activity: Design, synthesis, structure-activity relationship (SAR) and CYP53 docking studies.

Previously, we identified CYP53 as a fungal-specific target of natural phenolic antifungal compounds and discovered several inhibitors with antifungal properties. In this study, we performed similarity-based virtual screening and synthesis to obtain benzoic acid-derived compounds and assessed their antifungal activity against Cochliobolus lunatus, Aspergillus niger and Pleurotus ostreatus. In addition, we generated structural models of CYP53 enzyme and used them in docking trials with 40 selected compounds. Finally, we explored CYP53-ligand interactions and identified structural elements conferring increased antifungal activity to facilitate the development of potential new antifungal agents that specifically target CYP53 enzymes of animal and plant pathogenic fungi.

Purple rice bran extract attenuates the aflatoxin B1-induced initiation stage of hepatocarcinogenesis by alteration of xenobiotic metabolizing enzymes.

Pigmented rice bran has been suggested to be a valuable source of beneficial phytochemicals. We investigated genotoxic and anti-genotoxic effects of purple rice bran extract (PRBE) in rats using a liver micronucleus assay. Purple rice bran was extracted with methanol, obtaining large amounts of phenolic compounds, including anthocyanins and small amounts of gamma-oryzanol. The experimental protocols were divided into two sets. Male rats were divided into three groups. Group 1 was a negative control, while Groups 2 and 3 were fed with 100 and 500 mg/kg bw of PRBE, respectively, for 28 days. PRBE had no effect on micronucleus formation or xenobiotic metabolizing enzymes in rat liver. Experiments concerning the effect of PRBE on AFB1 showed that PRBE significantly lessened the amount of micronucleated hepatocytes in AFB1 treated rats. Furthermore, it modulated metabolic activation of AFB1 metabolism in the liver by suppressing activity and protein expression of CYP1A2, CYP3A and CYP 450 reductase, and enhancing phase II enzymes including GST and UGT. Overall, purple rice bran extract was not genotoxic in rats. It exhibited anti-genotoxicity by modulation some xenobiotic enzymes active in AFB1 metabolism.

Metabolic study of Angelica dahurica extracts using a reusable liver microsomal nanobioreactor by liquid chromatography-mass spectrometry.

Highly active and recoverable nanobioreactors prepared by immobilizing rat liver microsomes on magnetic nanoparticles (LMMNPs) were utilized in metabolic study of Angelica dahurica extracts. Five metabolites were detected in the incubation solution of the extracts and LMMNPs, which were identified by means of HPLC-MS as trans-imperatorin hydroxylate (M1), cis-imperatorin hydroxylate (M2), imperatorin epoxide (M3), trans-isoimperatorin hydroxylate (M1') and cis-isoimperatorin hydroxylate (speculated M2'). Compared with the metabolisms of imperatorin and isoimperatorin, it was found that the five metabolites were all transformed from these two major compounds present in the plant. Since no study on isoimperatorin metabolism by liver microsomal enzyme system has been reported so far, its metabolites (M1' and M3') were isolated by preparative HPLC for structure elucidation by (1) H-NMR and MS(2) analysis. M3' was identified as isoimperatorin epoxide, which is a new compound as far as its chemical structure is concerned. However, interestingly, M3' was not detected in the metabolism of the whole plant extract. In addition, a study with known chemical inhibitors on individual isozymes of the microsomal enzyme family revealed that CYP1A2 is involved in metabolisms of both isoimperatorin and imperatorin, and CYP3A4 only in that of isoimperatorin.

Effects of vitexin on the pharmacokinetics and mRNA expression of CYP isozymes in rats.

In traditional therapy with Chinese medicine, vitexin has several pharmacological properties, including antinociceptive, antispasmodic, antioxidant, antimyeloperoxidase, and α-glucosidase inhibitory activities. Recently, vitexin was shown to protect the heart against ischemia/reperfusion injury in an in vitro model by inhibiting apoptosis. The purpose of this study was to find out whether vitexin influences the effect on rat cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C11, and CYP3A1) by using cocktail probe drugs in vivo; the influence on the levels of CYP mRNA was also studied. A cocktail solution at a dose of 5 mL/kg, which contained phenacetin (10 mg/kg), tolbutamide (1 mg/kg), and midazolam (5 mg/kg), was given as oral administration to rats treated with short or long period of intravenous vitexin via the caudal vein. Blood samples were collected at a series of time points, and the concentrations of probe drugs in plasma were determined by HPLC-mass spectrometry (MS)/MS. The corresponding pharmacokinetic parameters were calculated by the software of DAS 2.0. In addition, real-time reverse transcription-polymerase chain reaction was performed to determine the effects of vitexin on the mRNA expression of CYP1A2, CYP2C11, and CYP3A1 in rat liver. Treatment with short or long period of vitexin had no effects on rat CYP1A2. However, CYP3A1 enzyme activity was inhibited by vitexin in a concentration-dependent and time-dependent manner. Furthermore, CYP2C11 enzyme activity was induced after short period treatment but inhibited after long period of vitexin treatment. The mRNA expression results were in accordance with the pharmacokinetic results. In conclusion, vitexin can either inhibit or induce activities of CYP2C11 and CYP3A1. Therefore, caution is needed when vitexin is co-administered with some CYP2C11 or CYP3A1 substrates in clinic, which may result in treatment failure and herb-drug interactions.

ω-3 polyunsaturated fatty acids-derived lipid metabolites on angiogenesis, inflammation and cancer.

Epidemiological and pre-clinical studies support the anti-tumor effects of ω-3 PUFAs; however, the results from human trials are mixed, making it difficult to provide dietary guidelines or recommendations of ω-3 PUFAs for disease prevention or treatment. Understanding the molecular mechanisms by which ω-3 PUFAs inhibit cancer could lead to better nutritional paradigms and human trials to clarify their health effects. The ω-3 PUFAs exert their biological activities mainly through the formation of bioactive lipid metabolites. Here we discuss the biology of cyclooxygenase, lipoxygenase and cytochrome P450 enzymes-derived ω-3-series lipid metabolites on angiogenesis, inflammation and cancer.

Effect of commercially available green and black tea beverages on drug-metabolizing enzymes and oxidative stress in Wistar rats.

The effect of commercially available green tea (GT) and black tea (BT) drinks on drug metabolizing enzymes (DME) and oxidative stress in rats was investigated. Male Wistar rats were fed a laboratory chow diet and GT or BT drink for 5 weeks. Control rats received de-ionized water instead of the tea drinks. Rats received the GT and BT drinks treatment for 5 weeks showed a significant increase in hepatic microsomal cytochrome P450 (CYP) 1A1 and CYP1A2, and a significant decrease in CYP2C, CYP2E1 and CYP3A enzyme activities. Results of immunoblot analyses of enzyme protein contents showed the same trend with enzyme activity. Significant increase in UDP-glucuronosyltransferase activity and reduced glutathione content in liver and lungs were observed in rats treated with both tea drinks. A lower lipid peroxide level in lungs was observed in rats treated with GT drink. Electrophoretic mobility shift assay revealed that both tea drinks decreased pregnane X receptor binding to DNA and increased nuclear factor-erythroid 2 p45-related factor 2 binding to DNA. These results suggest that feeding of both tea drinks to rats modulated DME activities and reduced oxidative stress in liver and lungs. GT drink is more effective on reducing oxidative stress than BT drink.