Kaori Yokotani

Ginkgo biloba extract attenuates warfarin-mediated anticoagulation through induction of hepatic cytochrome P450 enzymes by bilobalide in mice.

Ginkgo biloba extract (GBE) is a popular herbal ingredient used worldwide, but it is reported to induce bleeding as a serious adverse event. In this study we examined whether GBE induced spontaneous bleeding or accelerated warfarin anticoagulation via herb-drug interaction. Mice were given GBE or various active components of GBE orally for 5 days and blood coagulation parameters and hepatic cytochrome P450 enzymes (CYPs) were measured. Mice also received warfarin (racemate, (S)- or (R)-enantiomer) for the last 3 days of the 5-day regimen to examine GBE-warfarin interactions. Neither GBE (up to 1000 mg/kg) nor ginkgolide B (up to 140 mg/kg), a platelet-activating factor antagonist, influenced blood coagulation parameters. In contrast, GBE attenuated the anticoagulant action of warfarin. Bilobalide, a component of GBE that markedly induced hepatic CYPs including (S)-warfarin hydroxylase, showed similar effects. For (S)-warfarin, the anticoagulation action and the interaction with GBE was clear, while the influence on metabolism was greater for (R)-warfarin than for (S)-warfarin, which corresponded to the CYP types induced by GBE. These results suggest that GBE and ginkgolide B have no influence on blood coagulation in vivo, and that GBE attenuates the anticoagulation action of warfarin via induction of hepatic CYPs by bilobalide.

Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro

Objectives  This study aimed to determine whether Coleus forskohlii extract (CFE) influences the anticoagulant action of warfarin in mice in vivo and its relationship with hepatic cytochrome P450 (CYP).

Coleus forskohlii extract induces hepatic cytochrome P450 enzymes in mice

Coleus forskohlii root extract (CFE) is popular for use as a weight loss dietary supplement. In this study, the influence of standardized CFE containing 10% active component forskolin on the hepatic drug metabolizing system was investigated to evaluate the safety through its drug interaction potential. Male ICR mice were fed AIN93G-based diets containing 0-5% CFE or 0.05% pure forskolin for 2-3 weeks. Intake of two different sources of 0.5% CFE significantly increased the relative liver weight, total content of hepatic cytochrome P450 (CYP) and induced CYPs (especially 2B, 2C, 3A types) and glutathione S-transferase (GST) activities. CFE significantly increased mRNA expression of CYPs and GST with dose related responses. However, unlike the CFE, intake of 0.05% pure forskolin was found to be associated with only weak induction in CYP3A and GST activities with no significant increases in relative liver weight, total hepatic content or other CYPs activities. The inductions of CYPs and GST by CFE were observed at 1 week of feeding and rapidly recovered by discontinuation of CFE. These results indicated the induction potential of CFE on CYPs, and that this effect was predominantly due to other, as yet unidentified constituents, and not forskolin contained in CFE.

Inappropriate Usage of Dietary Supplements in Patients by Miscommunication with Physicians in Japan

Recently, people have used dietary supplements not only for nutritional supplementation, but also for treatment of their diseases. However, use of dietary supplements to treat diseases, especially with medications, may cause health problems in patients. In this study, we investigated use of dietary supplements in patients in Japan. This survey was conducted from January to December 2012, and was completed by 2732 people, including 599 admitted patients, 1154 ambulatory patients, and 979 healthy subjects who attended a seminar about dietary supplements. At the time of the questionnaire, 20.4% of admitted patients, 39.1% of ambulatory patients, and 30.7% of healthy subjects were using dietary supplements, which including vitamin/mineral supplements, herbal extracts, its ingredients, or food for specified health uses. The primary purpose for use in all groups was health maintenance, whereas 3.7% of healthy subjects, 10.0% of ambulatory patients, and 13.2% of admitted patients used dietary supplements to treat diseases. In addition, 17.7% of admitted patients and 36.8% of ambulatory patients were using dietary supplements concomitantly with their medications. However, among both admitted patients and ambulatory patients, almost 70% did not mention dietary supplement use to their physicians. Overall, 3.3% of all subjects realized adverse effects associated with dietary supplements. Communication between patients and physicians is important to avoid health problems associated with the use of dietary supplements.

Prevalence of inappropriate dietary supplement use among pregnant women in Japan

We investigated the characteristics of dietary supplements and their use by 1,076 Japanese pregnant women, the majority of whom were in mid- to late pregnancy. The subjects completed a self-reported survey on their sociodemographic characteristics, supplement use, and attitudes towards diet. The overall prevalence of supplement use did not change before and after pregnancy (75%); however, daily use increased by approximately twofold with pregnancy (20.2% versus 37.2%). After the onset of pregnancy, supplements containing folic acid were taken for fetal health. Daily users were more likely to be older, have a greater awareness of the risk of neural tube defects (NTD), view supplement use as acceptable, have less diet anxiety, and have more advisers regarding diet. Respondents used supplements containing folic acid alone or with other ingredients. Folic acid intake is recommended to reduce the risk of NTD. However, supplement use began after pregnancy recognition, suggesting a lack of knowledge on the appropriate timing of folic acid use. Information about supplements was obtained mostly from newspapers, magazines, flyers, and stores. These results indicate that more accurate information regarding the optimal timing of folic acid intake and the safety of dietary supplements must be disseminated.

Ascorbic Acid Levels and Neutrophil Superoxide Production in Blood of Pre-, Early and Late Hypertensive Stroke-Prone Spontaneously Hypertensive Rats

We compared ascorbic acid (AA) levels in the blood and TPA- and fMLP-stimulated superoxide (O2•−) production in neutrophils of pre-, early, and late hypertensive stroke-prone spontaneously hypertensive rats (SHRSP) with those of age-matched Wistar Kyoto rats (WKY), or two other normotensive strains of rats. Plasma and lymphocyte AA levels were about two-fold higher in SHRSP as early as 4 weeks old compared to WKY, and also higher than those of Wistar and Sprague-Dawley (SD) rats. Levels of AA were high in the liver and adrenal glands of SHRSP, indicating congenitally high AA levels. The production of O2•− in neutrophils was about two-fold higher in SHRSP than in WKY even at 4 weeks of age, and increased with age in both strains. Among SHRSP, AA levels in lymphocytes decreased at the late hypertensive stages with a decrease in hepatic l-gulono-γ-lactone oxidase (GLO) activities. These data suggest that bi-phasic AA levels in the blood of SHRSP comprise congenitally high levels and a decrease after persistent hypertension due to enhanced O2•− production and a decrease in de novo AA synthesis through GLO.

Resveratrol Partially Suppresses Inflammatory Events but Does not Affect Stroke Onset in Stroke-Prone Spontaneously Hypertensive Rats

AIM Resveratrol has been shown to mimic the beneficial effects of dietary restriction (DR). We previously reported that DR delays stroke onset and extends the lifespan in Stroke-Prone Spontaneously Hypertensive rats (SHRSP). Therefore, we examined whether resveratrol mimics DR and delays stroke onset in SHRSP. METHODS Cerebrovascular endothelial cells (CVECs) from SHRSP were treated with resveratrol, and the inflammatory gene expression levels and NFκB protein levels were measured. In order to address the effects of resveratrol in vivo, SHRSP (male, 10 weeks of age) were fed an experimental diet containing several doses of resveratrol (0 - 0.05% (w/w)), after which we measured the plasma cytokine levels and examined the stroke onset and lifespan. RESULTS Treatment with resveratrol (100 μM, 24 hours) in CVECs from SHRSP significantly decreased the interleukin (IL)-1β-induced monocyte chemoattractant protein-1 (MCP-1) mRNA expression levels and p50 and p65 protein levels in the nuclear fraction. When the SHRSP were fed a diet containing resveratrol for one week, the resveratrol treatment did not affect the plasma lipid and glucose levels, body weight or weight of each tissue. Resveratrol slightly, but not significantly, decreased the plasma levels of IL-1β and MCP-1 compared with that observed in the control group. In addition, resveratrol decreased the IL-1β and MCP-1 mRNA expression levels in the brain versus the control animals. However, no doses of resveratrol delayed stroke onset or extended the lifespan in SHRSP. CONCLUSIONS In this study, resveratrol did not delay stroke onset in SHRSP, although it partially suppressed systemic and cerebral inflammation. These results suggest that resveratrol does not mimic the beneficial effects of DR on stroke in vivo.

Induction of fatty liver by Coleus forskohlii extract through enhancement of de novo triglyceride synthesis in mice

Coleus forskohlii extract (CFE), an herbal ingredient, is used for weight-loss products. CFEs alleged efficacy is attributed to forskolin. However, CFE has been shown to induce fatty liver in mice, with components other than forskolin playing a part in this effect. The present study addressed the underlying mechanism of CFE-induced fatty liver by analyzing changes in CFE-treated mice of lipid concentrations and of the levels of mRNAs encoding enzymes and transcription factors known to be related to fatty liver. Mice were fed a diet containing 0, 0.3 and 1% CFE for 2 weeks. CFE at 1% clearly induced fatty liver, as demonstrated by histological examination and confirmed by increases in triglyceride concentrations in liver. However, treated mice did not exhibit elevation in plasma levels of non-esterified fatty acids. Comprehensive analysis of liver mRNA levels revealed accumulation of multiple transcripts, including mRNAs encoding enzymes acetyl-CoA carboxylase and long-chain elongase; transcription factor peroxisome proliferator-activated receptor gamma (PPARγ); and lipid-droplet-associated fat-specific protein 27 (Fsp27). These findings suggest that the de novo synthesis and accumulation of triglyceride in the liver, through the enhanced expression of specific lipogenic mRNAs, is a major underlying mechanism of fatty liver induction by CFE.