Nimbin analogs N5 and N7 regulate the expression of lipid metabolic genes and inhibit lipid accumulation in high-fat diet-induced zebrafish larvae: An antihyperlipidemic study.

BACKGROUND: Excess accumulation of lipids leads to obesity. Triterpenoids are a group of plant compounds which poses various biological activities. The biological activities of Nimbin analogs N5 and N7 were addressed in this study on inhibiting lipid aggregation and underlying the derivatives molecular mechanisms for a therapeutical approach. AIM: This study aims to evaluate the anti-adipogenic activity of semi-natural Nimbin analogs, N5 and N7, on zebrafish larvae induced with oxidative stress due to a high-fat diet (HFD) and adipogenesis using specific fluorescent stains. MATERIALS AND METHODS: Zebrafish at 4 days post fertilized (dpf) larvae were divided into groups for the HFD diet along with exposure to various concentrations of N5 and N7. HFD induced accumulation of neutral lipids and triglycerides (Oil Red O and Nile red staining, respectively) with weight gain, which generated intracellular ROS (DCFH-DA staining) and superoxide anion production (DHE staining) with depleted glutathione levels (NDA staining) were assayed. HFD exposure promoted the accumulation of inflammatory macrophages (Neutral red staining) and impaired glucose metabolism (2NBDG staining). The ability of N5 and N7 to reduce total regulating lipogenic specific genes C/EBP-α, SREBP-1 and FAS were evaluated using relative gene expression. KEY FINDINGS: The Nimbin analogues N5 and N7 suppressed adipogenesis, forming intracellular ROS and superoxide anion while simultaneously restoring glutathione levels. The analogues significantly lowered total TC and TG levels, prevented inflammatory macrophage build-up and boosted glucose absorption. Also, N5 and N7 down-regulate the lipogenic-specific genes. SIGNIFICANCE: Nimbin analogs N5 and N7 enhance lipolysis and inhibit adipogenesis in in-vivo zebrafish larvae model.

Transcriptomic and Metabonomic Profiling Reveals the Antihyperlipidemic Effects of Tartary Buckwheat Sprouts in High-Fat-Diet-Fed Mice.

Flavonoids are known for potent antioxidant activity and antihyperlipidemia. As a result of the few antinutritional factors and high bioactive substances, such as flavonoids, sprouts of tartary buckwheat (Fagopyrum tataricum, STB) have become healthy food. This study aims to unravel the antihyperlipidemic effects of STB in vivo and its potential mechanism through transcriptomic and metabonomic analysis. The physiological parameters of mice administered the high-fat diet with or without 2.5 and 5% of STB for 10 weeks were recorded. Liquid chromatography-tandem mass spectrometry and RNA sequencing were applied to obtain the serum lipid metabolomic and hepatic transcriptomic profiling, respectively. Results revealed that STB could significantly alleviate the increase of body weight, liver, and abdominal adipose while ameliorating the lipid content in serum and insulin resistance of mice fed with a high-fat diet. Notably, the metabonomic analysis identified the core differential metabolites mainly enriched in the pathways, such as fat digestion and absorption, insulin resistance, and other processes. Transcriptomic results revealed that STB significantly altered the expression levels of PIK3R1, LRP5, SLC10A2, and FBXO21. These genes are involved in the PI3K-AKT signaling pathway, digestion and absorption of carbohydrates, and type II diabetes mellitus pathways. In this study, STB exhibited remarkable influence on the metabolism of lipids and glucose, exerting antihyperlipidemic effects. STB have the potential for the development and application of a lipid-lowering health food.

CYP3A4 mediated pharmacokinetics drug interaction potential of Maha-Yogaraj Gugglu and E, Z guggulsterone.

Maha yogaraja guggulu (MYG) is a classical herbomineral polyherbal formulation being widely used since centuries. The aim of this study was to investigate the effect of MYG formulation and its major constituents E & Z guggulsterone on CYP3A4 mediated metabolism. In vitro inhibition of MYG and Guggulsterone isomers on CYP3A4 was evaluated by high throughput fluorometric assay. Eighteen Adult male Sprague-Dawley rats (200 ± 25 g body weight) were randomly divided into three groups. Group A, Group B and Group C were treated with placebo, MYG and Standard E & Z guggulsterone for 14 days respectively by oral route. On 15th day, midazolam (5 mg/kg) was administered orally to all rats in each group. Blood samples (0.3 mL) were collected from the retro orbital vein at 0.25, 0.5, 0.75, 1, 2, 4, 6, 12 and 24 h of each rat were collected. The findings from the in vitro & in vivo study proposed that the MYG tablets and its guggulsterone isomers have drug interaction potential when consumed along with conventional drugs which are CYP3A4 substrates. In vivo pharmacokinetic drug interaction study of midazolam pointed out that the MYG tablets and guggulsterone isomers showed an inhibitory activity towards CYP3A4 which may have leads to clinically significant interactions.

GC × GC-MS analysis and hypolipidemic effects of polyphenol extracts from Shanxi-aged vinegar in rats under a high fat diet.

Oxidative stress, inflammation and gut microbiota disorders can be induced by long-term high-fat diets (HFD). In order to confirm that polyphenols can improve these symptoms, polyphenols from Shanxi-aged vinegar (SAVEP) were extracted, and the components were detected by Comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-MS). 41 polyphenols include 18 phenolic acids and 17 polyphenols, which have not been reported. The mechanism of SAVEP on oxidative stress and inflammatory stress induced by HFD in rats and its regulating effect on intestinal flora disorder were studied. The results showed that SAVEP could significantly improve the lipid, inflammatory stress and oxidative stress related indicators compared with the Model group ("Model" refers to the group that successfully constructed a hyperlipidemia model by feeding HFD without any drugs or SAVEP in subsequent experiments.). In addition, SAVEP decreased the Firmicutes/Bacteroidetes ratio compared with the Model group, and elevated the relative abundance of beneficial bacteria. Conclusively, SAVEP can alleviate the oxidative stress and inflammatory stress caused by HFD, improving intestinal microbial disorders. The Spearman's correlation analysis revealed that Desulfovibrio, Lactobacillus and Akkermansia were correlated negatively with all of the inflammatory indicators, whereas Ruminococcus was the opposite. These results suggest that SAVEP may be a novel strategy against oxidative stress and inflammation, restoring the normal microbial community ecology of the gut and the treatment of metabolic syndromes.

Increased plasma concentrations of an antidyslipidemic drug pemafibrate co-administered with rifampicin or cyclosporine A in cynomolgus monkeys genotyped for the organic anion transporting polypeptide 1B1.

In vitro permeability and in vivo pharmacokinetics of pemafibrate were investigated in human intestinal and animal models untreated or pretreated with cyclosporine A or rifampicin to evaluate any drug interactions. Ratios of basal to apical apparent permeability (Papp) over apical to basal Papp in the presence of pH gradients decreased from 0.37 to 0.080 on rifampicin co-incubation, suggesting active transport of pemafibrate from basal to apical sides in intestinal models. Plasma concentrations of intravenously administered pemafibrate were enhanced moderately in control mice but only marginally in humanized-liver mice by oral pretreatment with rifampicin [an organic anion transporting polypeptide (OATP) 1B1 inhibitor] 1 h before the administration of pemafibrate. In three cynomolgus monkeys genotyped as wild-type OATP1B1 (2 homozygous and 1 heterozygous), oral dosing of cyclosporine A 4 h or rifampicin 1 h before pemafibrate administration significantly increased the areas under the plasma concentration-time curves (AUC) of intravenously administered pemafibrate by 4.9- and 7.4-fold, respectively. Plasma AUC values of three pemafibrate metabolites in cynomolgus monkeys were also increased by cyclosporine A or rifampicin. These results suggested that pemafibrate was actively uptaken in livers and rapidly cleared from plasma in cynomolgus monkeys; this rapid clearance was suppressible by OATP1B1 inhibitors.

Newly identified peptide hormone inhibits intestinal fat absorption and improves NAFLD through its receptor GPRC6A.

BACKGROUND & AIMS: Circulating peptides and G protein-coupled receptors (GPCRs) have gained much attention because of their biofunctions in metabolic disorders including obesity and non-alcoholic fatty liver disease (NAFLD). Herein, we aimed to characterize the role and therapeutic potential of a newly identified peptide hormone in NAFLD. METHODS: Using bioinformatics, we identified a murine circulating pentadecapeptide flanked by potential convertase cleavage sites of osteocalcin (OCN), which we named 'metabolitin (MTL)'. We used ligand-receptor binding, receptor internalization, bioluminescence resonance energy transfer and Nano isothermal titration calorimetry assays to study the binding relationship between MTL and GPRC6A. For in vivo biological studies, wild-type mice kept on a high-fat diet (HFD) were injected or gavaged with MTL to study its function in NAFLD. RESULTS: We confirmed that MTL binds to GPRC6A and OCN interacts with GPRC6A using in vitro biological studies. Both intraperitoneal and oral administration of MTL greatly improved NAFLD and insulin resistance in a mouse model. Interacting with GPRC6A expressed in intestines, MTL can significantly inhibit intestinal neurotensin secretion, which in turn inhibits triglyceride but not cholesterol gut absorption, mediated by the 5'AMP-activated protein kinase pathway. In addition, glucagon like peptide-1 secretion was induced by MTL treatment. CONCLUSIONS: Oral or intraperitoneal MTL significantly improves the symptoms of NAFLD by inhibiting lipid absorption and insulin resistance. MTL could be a potential therapeutic candidate for the treatment of NAFLD. LAY SUMMARY: A novel murine peptide hormone, herein named 'metabolitin', inhibits fatty acid absorption and improves systemic insulin resistance in a murine model of obesity and non-alcoholic fatty liver disease. Thus, metabolitin has therapeutic potential for the treatment of patients with non-alcoholic fatty liver disease.

Lipid-Lowering Effects of Medium-Chain Triglyceride-Enriched Coconut Oil in Combination with Licorice Extracts in Experimental Hyperlipidemic Mice.

Coconut oil has gained in popularity over recent years as a healthy oil due to its potential cardiovascular benefits. Coconut oil contains medium chain triglycerides (MCT) including lauric acid and capric acid that display beneficial properties in human health. Licorice ( Glycyrrhiza uralensis) is used as a sweetener and in traditional Chinese medicine with anti-inflammatory, antimicrobial, and antioxidant activities. This study investigated the in vivo effects of medium chain-triglycerides (MCT)-coconut oil (MCO) and its combination with licorice extract (LE-MCO) on serum lipid profile, hepatic steatosis, and local fat pad proteins in diet-induced obese mice. No liver toxicity was observed in 45% fat diet (HFD)-fed mice orally treated with LE, MCO, and LE-MCO for 12 weeks. Their supplementation reduced HFD-enhanced body weight, blood glucose, and insulin in mice. Plasma levels of both PLTP and LCAT were boosted in LE-MCO-administered mice. Supplementation of LE-MCO diminished plasma levels of TG and TC with concomitant reduction of the LDL-C level and tended to raise blood HDL-C level compared to that of HFD alone-mice. Treatment of LE-MCO encumbered the hepatic induction of hepatosteatosis-related proteins of SREBP2, SREBP1c, FAS, ACC, and CD36 in HFD-fed mice. Substantial suppression of this induction was also observed in the liver of mice treated with MCO. Oral administration of LE-MCO to HFD mice boosted hepatic activation of AMPK and the induction of UCP-1 and FATP1 in brown fat. Conversely, LE-MCO disturbed hepatic PPAR-LXR-RXR signaling in HFD-fed animals and reversed HFD-elevated epididymal PPARγ. Collectively, oral administration of LE-MCO may impede hyperlipidemia and hepatosteatosis through curtailing hepatic lipid synthesis.

Lipid-lowering effect of bergamot polyphenolic fraction: role of pancreatic cholesterol ester hydrolase.

Bergamot polyphenolic fraction (BPF) has been shown to positively modulate several mechanisms involved in metabolic syndrome, suggesting its use in therapy. In particular, it is able to induce a significant amelioration of serum lipid profile in hyperlipemic patients at different levels. The purpose of our study was to investigate the effect of BPF on cholesterol absorption physiologically mediated by pancreatic cholesterol ester hydrolase (pCEH). An in vitro activity assay was performed to study the effect of BPF on pCEH, whereas the rate of cholesterol absorption was evaluated through in vivo studies. In particular, male, Sprague-Dawley rats (200–225 g) were fed either normal chow or chow supplemented with 0.5% cholic acid, 5.5% peanut oil, and varying amounts of cholesterol (0 to 1.5%). BPF (10 mg/Kg) was daily administrated by means of a gastric gavage to animals fed with lipid supplemented diet for 4 weeks and, at the end of the study, plasma lipids and liver cholesteryl esters were measured in all experimental groups. Our results show that BPF was able to inhibit pCEH activity and this effect was confirmed, in vivo, via detection of lymphatic cholesteryl ester in rats fed with a cholesterol-rich diet. This evidence clarifies a further mechanism responsible for the hypolipemic properties of BPF previously observed in humans, confirming its beneficial effect in the therapy of hypercholesterolemia and in the treatment of metabolic syndrome.

Schisandra chinensis berry extract protects against steatosis by inhibiting histone acetylation in oleic acid-treated HepG2 cells and in the livers of diet-induced obese mice.

We hypothesized that hepatic steatosis could be mitigated by the hypolipidemic activity of Schisandra chinensis berry ethanol extract (SCE) via the inhibition of histone acetyltransferase (HAT) activity. HepG2 cells treated with oleic acid (OA) in the presence of SCE exhibited reduced OA-induced lipid accumulation, which was likely mediated by reductions in SREBP-1c expression. SCE attenuated the acetylation of total lysine and H3K9 that was otherwise increased by OA. Male obese mice fed with either a low-fat diet or Western diet exhibited reduced body and liver weights when supplemented with 1% SCE. The SCE-mediated attenuation of hepatic lipid accumulation was accompanied by a decrease in the expression of lipogenic genes. SCE also attenuated the expression of acetylated lysine and non-acetylated forms of H3K9 acetylation in the livers of these mice. Taken together, these results suggest that SCE has potential for further development as a novel therapeutic agent for the prevention of steatosis.

Antioxidant and hypolipidemic effects of soymilk fermented via Lactococcus acidophilus MF204.

Previous studies have shown that fermentations can enhance the bioactivity and absorption rate of soybean products. Fermented soybean products can alleviate hyperlipidemia and decrease risks of atherosclerosis and cardiovascular diseases. This study aimed to investigate the effects and mechanisms of soymilk fermented by Lactococcus acidophilus on blood lipids and antioxidant enzyme activities of rats fed with a high fat diet. Sixty rats were randomly assigned to six groups: normal control group (NC), high-fat control group (HFC), positive control group (cholestyramine, PC), Lactococcus acidophilus group (LA), soymilk group (SM), and fermented soymilk group (FSM), respectively. The NC group was fed with a basic diet, while the other groups were fed with a high-fat diet. After the experimental period (6 W), rats were sacrificed by decapitation. Blood and liver were collected to measure the concentrations of lipids and antioxidant enzyme activities. Results demonstrated that fermented soymilk could regulate lipid levels, restore HDL-c and TG to normal levels, and lower the concentrations of LDL-c than hypolipidemic drugs in hyperlipidemia rats. More importantly, fermented soymilk caused significant reduction in arteriosclerosis index and coronary risk index. Fermented soymilk also improved antioxidant capacities of hyperlipidemia rats. The increase of aglycone isoflavones in fermented soymilk could explain the above phenomena. In conclusion, soymilk fermented by Lactococcus acidophilus reduced risks of arteriosclerosis and coronary heart disease by regulating lipid levels and improving the antioxidant capacities of hyperlipidemia rats.

Hypolipidaemic effect and mechanism of paprika seed oil on Sprague-Dawley rats.

BACKGROUND: Details regarding the functional properties of paprika seed oil are relatively scarce. In this study the hypolipidaemic effects and mechanisms of paprika seed oil on Sprague-Dawley rats are explored, which may improve the usage of paprika seed source and provide a theoretical basis of paprika seed oil for the alleviation of hyperlipidaemia. RESULTS: In capsaicin and paprika seed oil (PSO) groups, total cholesterol (TC) and total triglyceride (TG) in serum and liver lipids of rats were significantly decreased (P < 0.05). The contents of serum HDL cholesterol were increased and the contents of serum LDL cholesterol were decreased (P < 0.05). Real-time PCR analyses revealed that the hepatic mRNA expression of fatty acid synthetase (FAS) is decreased and the expression levels of HSL is increased (P < 0.05). The mRNA expression of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) is decreased and the expression levels of low-density lipoprotein receptor (LDLR) is significantly improved (P < 0.05). The cholesterol 7-hydroxylase (CYP7A1) expression is regulated to control the cholesterol-to-bile acid transformation and cholesterol excretion is promoted. Capsaicin and unsaturated fatty acid PSO can activate and improve the mRNA expression of transient receptor potential vanilloid type-1 (TRPV1) and peroxisome proliferators-activated receptors (PPARα). CONCLUSION: The hypolipidaemic effects of paprika seed oil (PSO) may be attributed to the inhibition of lipid synthesis via suppressing the expression of HMG-CoAR, CYP7A1 and FAS, meanwhile, promoting the metabolism and excretion of lipids via up-regulating the expression of LDLR, HSL, TRPV1 and PPARα. © 2017 Society of Chemical Industry.

Role of gemfibrozil as an inhibitor of CYP2C8 and membrane transporters.

INTRODUCTION: Cytochrome P450 (CYP) 2C8 is a drug metabolizing enzyme of major importance. The lipid-lowering drug gemfibrozil has been identified as a strong inhibitor of CYP2C8 in vivo. This effect is due to mechanism-based inhibition of CYP2C8 by gemfibrozil 1-O-ß-glucuronide. In vivo, gemfibrozil is a fairly selective CYP2C8 inhibitor, which lacks significant inhibitory effect on other CYP enzymes. Gemfibrozil can, however, have a smaller but clinically meaningful inhibitory effect on membrane transporters, such as organic anion transporting polypeptide 1B1 and organic anion transporter 3. Areas covered: This review describes the inhibitory effects of gemfibrozil on CYP enzymes and membrane transporters. The clinical drug interactions caused by gemfibrozil and the different mechanisms contributing to the interactions are reviewed in detail. Expert opinion: Gemfibrozil is a useful probe inhibitor of CYP2C8 in vivo, but its effect on membrane transporters has to be taken into account in study design and interpretation. Moreover, gemfibrozil could be used to boost the pharmacokinetics of CYP2C8 substrate drugs. Identification of gemfibrozil 1-O-ß-glucuronide as a potent mechanism-based inhibitor of CYP2C8 has led to recognition of glucuronide metabolites as perpetrators of drug-drug interactions. Recently, also acyl glucuronide metabolites of clopidogrel and deleobuvir have been shown to strongly inhibit CYP2C8.

A conjugated fatty acid present at high levels in bitter melon seed favorably affects lipid metabolism in hepatocytes by increasing NAD(+)/NADH ratio and activating PPARα, AMPK and SIRT1 signaling pathway.

α-Eleostearic acid (α-ESA), or the cis-9, trans-11, trans-13 isomer of conjugated linolenic acid, is a special fatty acid present at high levels in bitter melon seed oil. The aim of this study was to examine the effect of α-ESA on hepatic lipid metabolism. Using H4IIEC3 hepatoma cell line, we showed that α-ESA significantly lowered intracellular triglyceride accumulation compared to α-linolenic acid (LN), used as a fatty acid control, in a dose- and time-dependent manner. The effects of α-ESA on enzyme activities and mRNA profiles in H4IIEC3 cells suggested that enhanced fatty acid oxidation and lowered lipogenesis were involved in α-ESA-mediated triglyceride lowering effects. In addition, α-ESA triggered AMP-activated protein kinase (AMPK) activation without altering sirtuin 1 (SIRT1) protein levels. When cells were treated with vehicle control (VC), LN alone (LN; 100µmol/L) or in combination with α-ESA (LN+α-ESA; 75+25µmol/L) for 24h, acetylation of forkhead box protein O1 was decreased, while the NAD(+)/NADH ratio, mRNA levels of NAMPT and PTGR1 and enzyme activity of nicotinamide phosphoribosyltransferase were increased by LN+α-ESA treatment compared to treatment with LN alone, suggesting that α-ESA activates SIRT1 by increasing NAD(+) synthesis and NAD(P)H consumption. The antisteatosis effect of α-ESA was confirmed in mice treated with a high-sucrose diet supplemented with 1% α-ESA for 5weeks. We conclude that α-ESA favorably affects hepatic lipid metabolism by increasing cellular NAD(+)/NADH ratio and activating PPARα, AMPK and SIRT1 signaling pathways.

The Effects of Solvent Polarity on Hypoglycemic and Hypolipidemic Activities of Securigera Securidaca (L.) Seeds.

The search for indigenous natural antidiabetic and antilipidemec agents is still ongoing. Medicinal plants are widely used for this purpose. These herbs are very rich sources of bioactive compounds as flavonoids, polyphenols, tannins, alkaloids which have been reported as effective role to reduce blood glucose and lipid levels. Securigera securidaca seed is reputed in folk medicine for their value as antidiabetic and antilipidemec drugs. In this research, the effect of solvent polarity in bioactive extraction contents of this plant was evaluated by GC-MS analysis. Then antidiabetic and antilipidemic activies of different extracts were investigated in streptozotocine-induced diabetic rats and compared to glibenclamide as known chemical drug for diabetes.The results indicated that, carbon tetrachloride extract of Securigera securidaca seeds showed the best and significant hypoglycemic and hypolipidemic activities compared to other extracts because of its more sterols and fatty acids content with beta cells protecting effect from high glucose-induced apoptosis and also increasing in insulin level and sensitivity.

CYP2C8 Is a Novel Target of Peroxisome Proliferator-Activated Receptor α in Human Liver.

Human cytochrome P450 (CYP) 2C enzymes metabolize ∼30% of clinically prescribed drugs and various environmental chemicals. CYP2C8, an important member of this subfamily, metabolizes the anticancer drug paclitaxel, certain antidiabetic drugs, and endogenous substrates, including arachidonic acid, to physiologically active epoxyeicosatrienoic acids. Previous studies from our laboratory showed that microRNA 107 (miR107) and microRNA 103 downregulate CYP2C8 post-transcriptionally. miR107 is located in intron 5 of the pantothenate kinase 1 (PANK1) gene. p53 has been reported to coregulate the induction of PANK1 and miR107. Here, we examine the possible downregulation of CYP2C8 by drugs capable of inducing miR107. Hypolipidemic drugs, such as bezafibrate, known activators of the peroxisome proliferator-activated receptor α (PPARα), induce both the PANK1 gene and miR107 (∼2.5-fold) in primary human hepatocytes. Surprisingly, CYP2C8 mRNA and protein levels were induced by bezafibrate. CYP2C8 promoter activity was increased by ectopic expression of PPARα in HepG2 cells, with a further increase after bezafibrate (∼18-fold), 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio acetic acid (∼10-fold) treatment, or the antidiabetic drug rosiglitazone, all known PPAR activators. Promoter sequence analyses, deletion studies, mutagenesis studies, and electrophoretic mobility shift assays identified a PPARα response element located at position -2109 base pair relative to the translation start site of CYP2C8. Chromatin immunopreciptation assay analysis confirmed recruitment of PPARα to this PPARα response element after bezafibrate treatment of human hepatocytes. Thus, we show for the first time that CYP2C8 is transcriptionally regulated by PPARα, suggesting the potential for drug-drug interactions due to upregulation of CYP2C8 by PPAR activators.

Hepatic Disposition of Gemfibrozil and Its Major Metabolite Gemfibrozil 1-O-ß-Glucuronide.

Gemfibrozil (GEM), which decreases serum triglycerides and low density lipoprotein, perpetrates drug-drug interactions (DDIs) with several drugs. These DDIs are primarily attributed to the inhibition of drug transporters and metabolic enzymes, particularly cytochrome P450 (CYP) 2C8 by the major circulating metabolite gemfibrozil 1-O-ß-glucuronide (GG). Here, we characterized the transporter-mediated hepatic disposition of GEM and GG using sandwich-cultured human hepatocytes (SCHH) and transporter-transfect systems. Significant active uptake was noted in SCHH for the metabolite. GG, but not GEM, showed substrate affinity to organic anion transporting polypeptide (OATP) 1B1, 1B3, and 2B1. In SCHH, glucuronidation was characterized affinity constants (Km) of 7.9 and 61.4 µM, and biliary excretion of GG was observed. Furthermore, GG showed active basolateral efflux from preloaded SCHH and ATP-dependent uptake into membrane vesicles overexpressing multidrug resistance-associated protein (MRP) 2, MRP3, and MRP4. A mathematical model was developed to estimate hepatic uptake and efflux kinetics of GEM and GG based on SCHH studies. Collectively, the hepatic transporters play a key role in the disposition and thus determine the local concentrations of GEM and more so for GG, which is the predominant inhibitory species against CYP2C8 and OATP1B1.

Optimization of Culture Conditions for Production of the Anti-Leukemic Glutaminase Free L-Asparaginase by Newly Isolated Streptomyces olivaceus NEAE-119 Using Response Surface Methodology.

Among the antitumor drugs, bacterial enzyme L-asparaginase has been employed as the most effective chemotherapeutic agent in pediatric oncotherapy especially for acute lymphoblastic leukemia. Glutaminase free L-asparaginase producing actinomycetes were isolated from soil samples collected from Egypt. Among them, a potential culture, strain NEAE-119, was selected and identified on the basis of morphological, cultural, physiological, and biochemical properties together with 16S rRNA sequence as Streptomyces olivaceus NEAE-119 and sequencing product (1509 bp) was deposited in the GenBank database under accession number KJ200342. The optimization of different process parameters for L-asparaginase production by Streptomyces olivaceus NEAE-119 using Plackett-Burman experimental design and response surface methodology was carried out. Fifteen variables (temperature, pH, incubation time, inoculum size, inoculum age, agitation speed, dextrose, starch, L-asparagine, KNO3, yeast extract, K2HPO4, MgSO4·7H2O, NaCl, and FeSO4·7H2O) were screened using Plackett-Burman experimental design. The most positive significant independent variables affecting enzyme production (temperature, inoculum age, and agitation speed) were further optimized by the face-centered central composite design-response surface methodology.

Lipidic dispersion to reduce food dependent oral bioavailability of fenofibrate: In vitro, in vivo and in silico assessments.

Novel formulations that overcome the solubility limitations of poorly water soluble drugs (PWSD) are becoming ever more critical to a drug development process inundated with these compounds. There is a clear need for developing bio-enabling formulation approaches to improve oral bioavailability for PWSD, but also to establish a range of predictive in vitro and in silico biopharmaceutics based tools for guiding formulation design and forecasting in vivo effects. The dual aim of this study was to examine the potential for a novel lipid based formulation, termed a lipidic dispersion, to enhance fasted state oral bioavailability of fenofibrate, while also assessing the predictive ability of biorelevant in vitro and in silico testing. Formulation as a lipidic dispersion improved both dissolution and solubilisation of fenofibrate through a combination of altered solid state characteristics and incorporation of solubilising lipidic excipients. These changes resulted in an increased rate of absorption and increased maximal plasma concentrations compared to a commercial, micronised product (Lipantil® Micro) in a pig model. Combination of biorelevant in vitro measurements with in silico physiologically based pharmacokinetic (PBPK) modelling resulted in an accurate prediction of formulation performance and forecasts a reduction in food effects on fenofibrate bioavailability through maximising its fasted state dissolution.

Underlying mechanism of drug-drug interaction between pioglitazone and gemfibrozil: Gemfibrozil acyl-glucuronide is a mechanism-based inhibitor of CYP2C8.

While co-administered gemfibrozil can increase the area under the concentration/time curve (AUC) of pioglitazone more than 3-fold, the underlying mechanism of the drug-drug interaction between gemfibrozil and pioglitazone has not been fully understood. In the present study, gemfibrozil preincubation time-dependently inhibited the metabolism of pioglitazone in the cytochrome P450 (CYP)- and UDP-glucuronosyltransferase (UGT)-activated human liver microsomes. We estimated the kinact and K'app values, which are the maximum inactivation rate constant and the apparent dissociation constant, of gemfibrozil to be 0.071 min(-1) and 57.3 µM, respectively. In this study, the kobs, in vivo value was defined as a parameter that indicates the potency of the mechanism-based inhibitory effect at the blood drug concentration in vivo. The kobs, in vivo values of potent mechanism-based inhibitors, clarithromycin and erythromycin, were estimated to be 0.0096 min(-1) and 0.0051 min(-1), respectively. The kobs, in vivo value of gemfibrozil was 0.0060 min(-1), which was comparable to those of clarithromycin and erythromycin, suggesting that gemfibrozil could be a mechanism-based inhibitor as potent as clarithromycin and erythromycin in vivo.

Glucose- and Triglyceride-lowering Dietary Penta-O-galloyl-α-D-Glucose Reduces Expression of PPARγ and C/EBPα, Induces p21-Mediated G1 Phase Cell Cycle Arrest, and Inhibits Adipogenesis in 3T3-L1 Preadipocytes.

Plant polyphenols, such as hydrolysable tannins, are present in the human diet and known to exhibit anti-diabetic and anti-obesity activity. We previously reported that the representative hydrolysable tannin compound α-penta-galloyl-glucose (α-PGG) is a small molecule insulin mimetic that, like insulin, binds to insulin receptor (IR) and activates the IR-Akt-GLUT4 signaling pathway to trigger glucose transport and reduce blood glucose levels in db/db and ob/ob diabetic mice. However, its effects on adipogenesis and lipid metabolism were not known. In this study, high fat diet (HFD)-induced diabetic and obese mice were treated with α-PGG to determine its effects on blood glucose and triglycerides. 3T3-L1 preadipocytes were used as a cell model for identifying the anti-adipogenic activity of α-PGG at molecular and cellular levels as a first step in elucidating the mechanism of action of the compound. In vivo, oral administration of α-PGG significantly reduced levels of blood glucose, triglyceride, and insulin in HFD-induced diabetic/obese mice (P<0.05). In vitro, α-PGG inhibited the differentiation of 3T3-L1 preadipocytes into mature adipocytes. α-PGG suppressed the expression of positive adipogenic factors PPARγ C/EBPα and mTOR and augmented the negative adipogenic factor Pref-1. Furthermore, α-PGG induced upregulation of p21 and G1 phase cell cycle arrest. In contrast, adipogenic signaling pathways mediated by insulin, the cAMP response element binding protein (CREB) and glucocorticoid receptor (GR), were not inhibited. RNAi knockdown of p21 led to a 4-fold increase in triglyceride level in 3T3-L1 preadipocytes treated with MDI and α-PGG compared to regular preadipocytes. These results indicate, for the first time, that α-PGG is blood triglyceride- and glucose-lowering in HFD-induced obese and diabetic mice. It selectively inhibited some but not all major adipogenic pathways as well as the mTOR-p21-mediated cell cycle regulatory pathway. It is very likely that these apparently diverse but coordinated activities together inhibited adipogenesis. These results expand our knowledge on how PGG works in adipocytes and further confirm that α-PGG functions as an orally-deliverable natural insulin mimetic with adipogenetic modulatory functions.