BackgroundDifferent patient groups are known to use herbal remedies and conventional drugs concomitantly (co-use). This poses a potential risk of herb-drug interaction through altering the drug’s pharmacokinetics or pharmacodynamics. Little is known about co-use among patients in general practice. The primary aim of this study was to compare patients in general practice that co-use herbal remedies and conventional drugs with those who do not. The secondary aim was to register the herb-drug combinations with potential clinical relevant interactions among the co-users.MethodA questionnaire based cross-sectional study conducted in the autumn 2011 in a general practice office with four general practitioners (GPs) and one intern in Western Norway. Adults >18 years who came for an office visit were invited. The questionnaire asked about demographics, herbal use, conventional drug use and communication about herbal use. Multivariable logistic regression was used to compare co-users to the other patients.ResultsOf the 381 patients who completed the questionnaire, the prevalence of herbal use was 44%, with bilberry (41%), green tea (31%), garlic (27%), Aloe vera (26%) and echinacea (18%) as the most frequently used. Among those using conventional drugs regularly, 108 (45%) co-used herbs. Close to 40% of patients on anticoagulants co-used herbs, with garlic and bilberry as the most frequent herbs. Compared to all other patients, co-users had significantly (p < 0.05) increased odds to be female (adjOR 2.0), age above 70 years (adjOR 3.3), use herbs to treat an illness (adjOR 4.2), use two or more herbs (polyherbacy, adjOR 12.1) and having experienced adverse effects of herbal use (adjOR 37.5). Co-use was also associated with use of analgesics or dermatological drugs (adjOR 5.1 and 7.9 respectively). Three out of four patients did not discuss herbal use with any health care professional.ConclusionA sizable proportion of the GP patients co-used herbs with conventional drugs, also combinations with reported interaction potential or additive effects like anticoagulants and garlic. The low disclosure of herbal use to their GP, polyherbacy and the risk of interactions in vulnerable groups like elderly and chronically ill patients, warrant increased awareness among GPs.

Grain-coating chlorites in clastic quartz-rich sandstones have long been recognized as an important porosity-preserving constituent in medium- to deep-burial diagenesis. As little is known about the occurrence and origin of chlorite coatings, chlorite synthesis experiments were performed to study how grain-coating chlorites form in certain sandstones during burial. The starting material was naturally-occuring sandstones from the Oseberg and the Veslefrikk fields offshore Norway, where the same sandstone formation is buried to different depths due to faulting. Grain-coating chlorites exist below ~3000 m burial depth only. At shallower burial (2400 m), an X-ray amorphous iron containing thin clay coating is present.The samples were heated to 200 and 250°C (at water vapour pressure) in a hydrothermal bomb for 2–4 weeks. Both starting material and end-products were studied (electron-) optically in both scanning and transmission microscopes. The TEM showed the Fe-rich precursor material to consist of a fine-grained berthierine-dominated mixed-layer. The neoformed grain coatings in the reacted samples were similar in appearance to naturally-occurring chlorite coatings. The TEM analyses of individual grains documented an Fe-rich chloritic phase with an average composition of Mg0.41Fe3.52Mn0.10Al1.51(Al0.58Si3.42)O10(OH)8. The reacted waters were found to be close to saturation with the newly formed chlorites.Grain-coating chlorite thus appears to form in the natural environment from Fe-rich berthierine precursors at a burial depth corresponding to a temperature around 90°C.

The aim of this study was to evaluate the in vitro inductive potential of six commonly used trade herbal products on CYP1A2, CYP2D6 and CYP3A4 metabolic activities. Herbal components were extracted from the trade products in a way that ensured a composition equal to that present in the original product. Primary human hepatocytes and specific CYP substrates were used. Classic inducers were used as positive controls and herbal extracts were added in in vivo -relevant concentrations. Metabolites were determined by high performance liquid chromatography (HPLC). St. John's wort and common valerian were the strongest inducing herbs. In addition to induction of CYP3A4 by St. John's wort, common valerian and Ginkgo biloba increased the activity of CYP3A4 and 2D6 and CYP1A2 and 2D6, respectively. A general inhibitory potential was observed for horse chestnut, Echinacea purpurea and common sage. St. John's wort inhibited CYP3A4 metabolism at the highest applied concentration. Horse chestnut might be a herb with high inhibition potentials in vivo and should be explored further at lower concentrations. We show for the first time that G. biloba may exert opposite and biphasic effects on CYP1A2 and CYP2D6 metabolism. Induction of CYP1A2 and inhibition of CYP2D6 were found at low concentrations; the opposite was observed at high concentrations. CYP2D6 activity, regarded generally as noninducible, was increased by exposure to common valerian (linear to dose) and G. bilob a (highest concentration). An allosteric activation is suggested. From the data obtained, G. biloba , common valerian and St. John's wort are suggested as candidates for clinically significant CYP interactions in vivo .The use of herbs as alternative and/or complementary therapy in the Western world is on the rise and gaining increasing popularity. As people often take different herbs in combination with prescribed Western medication [1], there is a potential for both pharmacokinetic and pharmacodynamic herb-drug interactions. In addition to doctor's recommendations [2], patients are also self-medicating with several different herbs and herbal preparations, thinking it is safe [3,4], and often without informing their primary physician.It is important that possible interactions are discovered in order to avoid clinical implications, as shown for example between oral contraceptives and St. John's wort [5], cyclosporine and St. John's wort [6], and between Ginkgo and warfarin [7]. These are just a few of many [8], and we need to identify such harmful combinations in order to avoid serious and negative effects of concurrent use.Cytochrome P450 (CYP) is a superfamily of enzymes, predominantly expressed in the liver, but also in the respiratory tract, lungs, brain and the small intestine [9,10]. CYP isoenzymes are the most important phase 1 enzyme system in the metabolism of xenobiotics, including Western medicines, endogenous compounds and herbal components as effective substrates [11]. Herb-drug interactions can appear when herbs and chemical drugs are co...

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Extracts of six commonly used commercially available herbal products, St. John's wort, common valerian, common sage, Ginkgo biloba , Echinacea purpurea and horse chestnut were investigated for their in vitro inhibitory potential of CYP3A4 mediated metabolism and P-glycoprotein efflux transport activity. C-DNA baculovirus expressed CYP3A4 and Caco-2 cells were used. Ketoconazole and verapamil were applied as positive control inhibitors, respectively. A validated high-performance liquid chromatography methodology was used to quantify the formation of 6-OH-testosterone and scintillation counting was used to quantify the transport of 3 H-digoxin. All the investigated herbs inhibited CYP3A4 activity. St. John's wort was the strongest inhibiting herb with an IC 50 value of 15.4 μ g/ml, followed by common sage, Ginkgo biloba , common valerian, horse chestnut and Echinacea purpurea . All herbs also inhibited P-glycoprotein activity. Ginkgo biloba was the strongest inhibiting herb, inhibiting the net digoxin flux with an IC 50 value of 23.6 μ g/ml, followed by St. John's wort, horse chestnut, common sage, common valerian and Echinacea purpurea . No correlation was found between the herbs inhibitory potentials towards CYP3A4 and P-glycoprotein activities. Ginkgo biloba , horse chestnut and common sage, besides St. John's wort, are suggested candidates for in vivo intestinal herb-drug pharmacokinetic interactions.

Nicotine measurement in hair is a practical and valid method for estimating average ETS exposure in children. An underreporting of ETS exposure was indicated.

The toxicokinetic properties of C6 to C10 n-alkanes, aromates and naphthenes have been investigated in rats during inhalation of 100 p.p.m. of the single hydrocarbons for 3 days, 12 hr/day. The concentration of hydrocarbon was measured by head space gas chromatography in blood, brain, liver, kidneys and perirenal fat at days 1, 2 and 3, immediately after termination of exposure and 12 hr after exposure on day 3. The main conclusions drawn from the study were: a) Aromatic hydrocarbons show high concentrations in blood and low concentrations in organs. b) Naphthenic hydrocarbons show low concentrations in blood and high concentrations in organs. c) n-Alkanes show very low concentrations in blood, relatively high concentrations in brain and a high potential for accumulation in fat with repeated exposures. d) Biological concentrations of hydrocarbons within one class increase in general with increasing molecular weight, though with specific exceptions. e) Accumulation is obviously influenced by differences in metabolism and enzyme induction potential. f) Lipid solubility is not the only parameter relevant for the evaluation of hydrocarbon accumulation.

This is the first survey comparing concurrent herbal use between cancer patients undergoing palliative or curative chemotherapy. Both groups frequently use herbal remedies concurrent with chemotherapy, but with a slightly different intent. The frequent concurrent use emphasizes the need for clinicians to include questions on complementary and alternative medicine in routine history taking and for further studies on possible herb-drug interactions among the cancer patient.