Interactions Between Herbal Medicines and Prescribed Drugs

In Vitro Evaluation of Reversible and Time-Dependent Inhibitory Effects of Kalanchoe crenata on CYP2C19 and CYP3A4 Activities

Kalanchoe crenata popularly known as "dog's liver" is used in most African countries for the treatment of chronic diseases such as diabetes, asthma and HIV/AIDS related infections. The evaluation of K. crenata for herb-drug interactions has not been reported. This study therefore aims to evaluate the risk of K. crenata for herb-drug interaction in vitro. Crude methanol and fractions of K. crenata were incubated and preincubated with recombinant human CYP2C19 and CYP3A4. Comparative studies were conducted in both human liver microsomes and recombinant human CYP to ascertain the inhibition profile of the crude extract and the various fractions. The cocktail approach of recombinant human CYPs was conducted to confirm the inhibition potential of the fractions in the presence of other CYPs. The results showed significant time-dependent inhibition of tested samples on CYP3A4 with crude methanol (39KC), fractions 45A, 45B and 45D given IC50 fold decrease of 3.29, 2.26, 1.91 and 1.49, respective. Time dependent kinetic assessment of 39KC and 45D showed KI and kinact values for 39KC as 1.77 µg/mL and 0.091 min(-1) while that of 45D were 6.45 µg/mL and 0.024 min(-1), respectively. Determination of kinact based on IC50 calculations yielded 0.015 and 0.04 min(-1) for 39KC and 45D, respectively. Cocktail approach exhibited fold decreases in IC50 for all test fractions on CYP3A4 within the ranges of 2.10 - 4.10. At least one phytoconstituent in the crude methanol extract of Kalanchoe crenata is a reversible and time-dependent inhibitor of CYP3A4.

Diindolylmethane, a naturally occurring compound, induces CYP3A4 and MDR1 gene expression by activating human PXR

Activation of human pregnane X receptor (hPXR)-regulated expression of cytochrome P450 3A4 (CYP3A4) and multidrug resistance protein 1 (MDR1) plays an important role in mediating adverse drug interactions. Given the common use of natural products as part of adjunct human health behavior, there is a growing concern about natural products for their potential to induce undesired drug interactions through the activation of hPXR-regulated CYP3A4 and MDR1. Here, we studied whether 3,3'-diindolylmethane (DIM), a natural health supplement, could induce hPXR-mediated regulation of CYP3A4 and MDR1 in human hepatocytes and intestinal cells. DIM, at its physiologically relevant concentrations, not only induced hPXR transactivation of CYP3A4 promoter activity but also induced gene expression of CYP3A4 and MDR1. DIM decreased intracellular accumulation of MDR1 substrate rhodamine 123, suggesting that DIM induces the functional expression of MDR1. Pharmacologic inhibition or genetic knockdown of hPXR resulted in attenuation of DIM induced CYP3A4 and MDR1 gene expression, suggesting that DIM induces CYP3A4 and MDR1 in an hPXR-dependent manner. Together, these results support our conclusion that DIM induces hPXR-regulated CYP3A4 and MDR1 gene expression. The inductive effects of DIM on CYP3A4 and MDR1 expression caution the use of DIM in conjunction with other medications metabolized and transported via CYP3A4 and MDR1, respectively.

Understanding interactions between Chinese medicines and pharmaceutical drugs in integrative healthcare

In the 21st century, the public are more informed, mainly via the Internet, about health and medical products and have become more knowledgeable about matters relating to their health conditions and well-being in curing and preventing illnesses. They often self-medicate themselves with various health products and over-the-counter (OTC) medicines apart from prescribed pharmaceutical drugs (PD). Some of those non-prescribed products may have doubtful quality control and contain harmful additives or unchecked ingredients; thus their usefulness is in doubt. The increasing popularity world-wide of using Chinese medicines (CM) and related OTC functional products has raised concerns over their concomitant use with PD and the consequential adverse effects. In most cases the alleged causes of adverse effects are linked with herbal sources, although the authorised information on the interactions between CM-PD is not plentiful in the literature. There is an urgent need for such a data base. The future professionals in health and medical care should be knowledgeable or aware of what their patients have been taking or given. In actual practice the patients may receive both treatments intentionally or unintentionally, with or without the awareness of the practitioner. In these situations a reliable database for interactions between CM-PD will be extremely useful for consultation when treatment problems appear or during emergency situations. Their combining of medications may be involved with possible outcomes of adverse reactions or beneficial effects. Such a database will be welcomed by both practitioners of herbal medicines and orthodox medicine practitioners in the emerging trend of integrative medicine. The author has been involved in various research projects of basic and clinical aspects in mainly CM among other herbal and PD. Examples will be given largely on those related to these disciplines as illustrations in this overview.

Effects of Guanxinning injection on rat cytochrome P450 isoforms activities in vivo and in vitro

1. We aimed to investigate the regulatory effects of Guanxinning injection (GXNI) on activities of cytochrome P1A2 (CYP1A2), CYP2C11, CYP2D1 and CYP3A1/2 by probe drugs in rats in vivo and in vitro. 2. GXNI-treated and blank control groups were administered GXNI and physiological saline by caudal vein for 14 days consecutively, then they were given the probe drugs of caffeine (10 mg/kg), tolbutamide (10 mg/kg), metoprolol (20 mg/kg) and dapsone (10 mg/kg) by intraperitoneal injection. The blood samples were collected at different times for ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. Changes of the pharmacokinetics parameters between the GXNI-treated and the blank control groups were used to evaluate the effects of GXNI on the four CYP450 isoforms in rats in vivo. After blood collection, the livers of rats were taken and made microsomes for in vitro tests. The relevant metabolites of phenacetin, tolbutamide, dextromethorphan and testosterone were analyzed quantitatively by high-performance liquid chromatography (HPLC) after microsome incubation. The statistical differences between the two groups were observed to detect the effects of GXNI on the four CYP450 isoforms in rats in vitro. 3. The in vivo and in vitro results demonstrated that GXNI could induce CYP1A2 activity in rats, but had no significant effects on CYP2C11, CYP2D1 and CYP3A1/2.

[Phytotherapy in the German Medical AWMF S3 guidelines - a systematic overview]

In Germany, the interdisciplinary, evidence- and consensus-based medical AWMF S3 guidelines represent the highest available scientific level and have significant impact on patient care. In Germany, Austria, and Switzerland, herbal medicine has a long tradition in medical care. Of notice, the evidence for its efficacy in numerous indications is increasing. This systematic review evaluates to which extent phytotherapy is taken into account in the current S3 guidelines. In all available medical AWMF S3 guidelines, the recommendations/statements on phytotherapeutic options were identified, and 2 independent experts classified them into 3 categories: positive, negative, and open. In addition, comments on side effects and interactions were extracted. Phytotherapeutic options are specified in 40 (31.3 %) out of 128 AWMF S3 guidelines. Phytotherapy was not included in 55 guidelines (42.9%) with potential herbal therapeutic options. From 204 recommendations 139 (68.1%) are negative or remain open. In 27 guidelines (67.5%) phytotherapy is listed in the chapter for complementary and alternative medicine and/or miscellaneous, in 7 guidelines (17.5%) it is mentioned at the end of the recommendations on medical drug therapy, and in 8 guidelines (20.0%) it is listed in the recommendations regarding conventional treatments. Side effects and interactions are stated in 70 out of 204 recommendations (34.3%). Less than half of the currently available medical AWMF S3 guidelines include phytotherapy in their search strategy. Only few positive statements and recommendations on herbal medicine are taken into account. A systematic and comprehensive work up of the existing evidence on the one hand and the consequent incorporation on the other is necessary to appropriately integrate phytotherapy in the German medical guidelines.

Potential of garlic (Allium sativum) in lowering high blood pressure: mechanisms of action and clinical relevance

Garlic supplements have shown promise in the treatment of uncontrolled hypertension, lowering blood pressure (BP) by about 10 mmHg systolic and 8 mmHg diastolic, similar to standard BP medication. Aged garlic extract, which contains S-allylcysteine as the bioactive sulfur compound, in particular is standardizable and highly tolerable, with little or no known harmful interaction when taken with other BP-reducing or blood-thinning medication. Here we describe biologically plausible mechanisms of garlic's BP-lowering effect. Garlic-derived polysulfides stimulate the production of the vascular gasotransmitter hydrogen sulfide (H2S) and enhance the regulation of endothelial nitric oxide (NO), which induce smooth muscle cell relaxation, vasodilation, and BP reduction. Several dietary and genetic factors influence the efficiency of the H2S and NO signaling pathways and may contribute to the development of hypertension. Sulfur deficiency might play a part in the etiology of hypertension, and could be alleviated with supplementation of organosulfur compounds derived from garlic.

Interactions between herbs and antidiabetics: an overview of the mechanisms, evidence, importance, and management

Complementary and alternative therapies are quickly gaining importance because they are perceived to be free of side effects due to their natural origin. However, herbal remedies are complex mixtures of bioactive entities, which may interact with prescription drugs through pharmacokinetic or pharmacodynamic mechanisms and sometimes result in life-threatening consequences. In particular, diabetes patients are often treated with multiple medications due to different comorbidities, and such patients use antidiabetic medications for their entire lives; thus, it is important to make the public aware of herb interactions with antidiabetic drugs. In this paper, we summarize the reports available on the interaction of herbal remedies with oral hypoglycemic agents and describe mechanisms, preclinical or clinical evidence, importance, and management strategies.

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.

Thiazide-like diuretic drug metolazone activates human pregnane X receptor to induce cytochrome 3A4 and multidrug-resistance protein 1

Human pregnane X receptor (hPXR) regulates the expression of drug-metabolizing enzyme cytochrome P450 3A4 (CYP3A4) and drug transporters such as multidrug-resistance protein 1 (MDR1). PXR can be modulated by small molecules, including Federal Drug Administration (FDA)-approved drugs, thus altering drug metabolism and causing drug-drug interactions. To determine the role of FDA-approved drugs in PXR-mediated regulation of drug metabolism and clearance, we screened 1481 FDA-approved small-molecule drugs by using a luciferase reporter assay in HEK293T cells and identified the diuretic drug metolazone as an activator of hPXR. Our data showed that metolazone activated hPXR-mediated expression of CYP3A4 and MDR1 in human hepatocytes and intestine cells and increased CYP3A4 promoter activity in various cell lines. Mammalian two-hybrid assays showed that hPXR recruits its co-activator SRC-1 upon metolazone binding in HepG2 cells, explaining the mechanism of hPXR activation. To understand the role of other commonly-used diuretics in hPXR activation and the structure-activity relationship of metolazone, thiazide and non-thiazide diuretics drugs were also tested but only metolazone activates hPXR. To understand the molecular mechanism, docking studies and mutational analysis were carried out and showed that metolazone binds in the ligand-binding pocket and interacts with mostly hydrophobic amino acid residues. This is the first report showing that metolazone activates hPXR. Because activation of hPXR might cause drug-drug interactions, metolazone should be used with caution for drug treatment in patients undergoing combination therapy.

PdCl2 catalyzed efficient assembly of organic azides, CO, and alcohols under mild conditions: a direct approach to synthesize carbamates

A simple and readily available PdCl2 catalyzed carbamate synthesis method via isocyanate generation and application in situ has been developed. This chemistry provides an efficient and practical approach to synthesize carbamates from simple organic azides, CO atmosphere and alcohols. The broad scope, mild and neutral conditions, and only N2 as the byproduct make this transformation very useful. Moreover, simple examples of modification of bioactive molecules and construction of macrocycles were achieved through this protocol.

Pharmacokinetic comparisons of benzoylmesaconine in rats using ultra-performance liquid chromatography-tandem mass spectrometry after administration of pure benzoylmesaconine and Wutou decoction

Wutou decoction is widely used in China because of its therapeutic effect on rheumatoid arthritis. Benzoylmesaconine (BMA), the most abundant component of Wutou decoction, was used as the marker compound for the pharmacokinetic study of Wutou decoction. The aim of the present study was to compare the pharmacokinetics of BMA in rats after oral administration of pure BMA and Wutou decoction. Pure BMA (5 mg/kg) and Wutou decoction (0.54 g/kg, equivalent to 5 mg/kg BMA) were orally administered to rats with blood samples collected over 10 h. Quantification of BMA in rat plasma was achieved using sensitive and validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Specifically, the half-life (T_1/2) and mean residence time values of pure BMA were 228.3 ± 117.0 min and 155.0 ± 33.2 min, respectively, whereas those of BMA in Wutou decoction were decreased to 61.8 ± 35.1 min and 55.8 ± 16.4 min, respectively. The area under the curve (AUC) of BMA after administration of Wutou decoction was significantly decreased (five-fold) compared with that of pure BMA. The results indicate that the elimination of BMA in rats after the administration of Wutou decoction was significantly faster compared with that of pure BMA.

A systematic review on the efficacy, safety and types of Chinese herbal medicine for depression

Chinese herbal medicine (CHM) is one of the commonly used complementary and alternative medicine therapies for major depressive disorder. The objective of this study was to review the efficacy, safety and types of CHM for depression. We systematically searched key databases (9 Chinese and 7 English) up until May 2013 for randomized controlled trials (RCTs) and examined 7 systematic reviews for additional articles. Methodological quality was assessed by modified Jadad scale and Cochrane's risk of bias assessment. Only studies with moderate methodological quality, defined as modified Jadad scale score ≥3, were included in meta-analysis for efficacy. Of the 296 RCTs that were assessed in details, 278 (93.9%) had modified Jadad scale score < 3, and only 21 scored ≥ 3. The frequently used formulas were Xiao Yao decoction, Chaihu Shugan decoction and Ganmai Dazao decoction; while Chaihu, Bai Shao and Fu Ling were the frequently used single herb. Meta-analyses showed that CHM monotherapy was better than placebo and as effective as antidepressants in reducing Hamilton Depression Rating Scale (HDRS) score (CHM vs. placebo: mean difference: -7.97, 95% CI: -10.25 to -5.70, P < 0.00001, 2 studies; CHM vs. antidepressants: mean difference: 0.01, 95% CI: -0.28 to 0.30, P = 0.95, 7 studies). CHM were associated with less adverse events than antidepressants, and adding CHM to antidepressants reduced adverse events. Despite the overall positive results, due to the small number of studies with sufficient methodological quality, it is premature to accurately conclude the benefits and risks of CHM for depression.

Provider and patient expectations for dietary supplement discussions

BACKGROUND

Dietary supplement use in the United States is common. Patients can procure supplements without a prescription, and often do not disclose supplement use to their healthcare providers. Providers and patients may be uncertain about what would be appropriate or helpful in discussions of supplements during routine office visits.

OBJECTIVE

To explore provider and patient expectations for discussions of dietary supplements.

DESIGN

Semi-structured interviews were conducted with a purposeful sample of healthcare providers from three specialties and their patients who reported taking supplements.

PARTICIPANTS

Thirty-five outpatient providers (14 primary care, six integrative medicine, and 15 complementary and alternative medicine (CAM) providers) and 107 of their patients.

APPROACH

Qualitative analysis of transcripts using grounded theory and iterative review.

RESULTS

Both providers and patients raised twelve common topics about dietary supplements that they felt were important to discuss during office visits, such as: supplements taken; supplement risks (interactions, safety/harm, side effects/adverse events); treatment benefits; efficacy; alternative treatments; and patient expectations/preferences for treatment. Some topics were mentioned more frequently by providers than patients, such as how to take, reason for taking, and evidence for use. Providers raised several topics that were mentioned infrequently by patients. Supplement costs and regulations were not brought up by any patients, even though consideration of these topics could influence patient decisions to take supplements. Complementary healthcare providers brought up topics not mentioned by primary care providers, such as the importance of supplement brands and supplement mega-dosing.

CONCLUSIONS

Patients and providers have concordant views about the need to discuss patient supplement use and ensure patient safety. Patients may undervalue, be unaware of, or discount information about cost or regulations that could affect their decision-making about supplement use. Future studies could examine the value, acceptability, and influence of a more comprehensive approach to discussions to help patients appropriately evaluate supplements.

Hypericum perforatum-induced hepatotoxicity with possible association with copaiba (Copaifera langsdorffii Desf):case report

We report a case of liver damage in an elderly patient after the use of herbal products of Hypericum perforatum and copaiba (Copaifera langsdorffii Desf). Hepatotoxicity related to Hypericum perforatum is anecdotally known, but for copaiba, widely used as anti-inflammatory, there is just experimental data in the national literature. This report aimed to draw attention to the possible toxic effects of this association as well as to the clinical recovery of the patient after discontinuing their use. There is a tendency to suspect of the action of drugs to justify a non-viral acute liver injury, because of the large number of drugs responsible for hepatotoxicity. There are experiments and clinical reports in the literature describing some herbal products, including Hypericum perforatum, as the causative agents of this aggression, and are considered innocuous and used with no restrictions. We must remember that adverse reactions also occur with these substances; hence, they should be investigated when collecting the patient´s history, for leading to severe liver failure.

Natural products and supplements for geriatric depression and cognitive disorders: an evaluation of the research

Numerous geriatric patients are using Complementary and Alternative Medicine (CAM) for late-life mood and cognitive disorders. Natural products and supplements are a common CAM intervention which have risks and benefits of which patients should be appropriately advised. The data for omega-3 fatty acids, ginkgo biloba, SAMe, St John's wort, B vitamins and vitamin D, huperzine, caprylidene, and coconut oil will be evaluated. Since the evidence basis for natural products and supplements is limited, especially for the geriatric population, studies involving the general adult population are included to infer effects in the aging population. Despite the data available, more rigorous studies with larger sample sizes over longer periods of time are still needed. Regardless of a physician's preference to recommend various natural supplements and products, a physician could protect their patients by having an understanding of the side effects and indications for various natural products.

Clinical applications of herbal medicines for anxiety and insomnia; targeting patients with bipolar disorder

OBJECTIVES

Patients with bipolar disorder frequently continue to experience residual anxiety and insomnia between mood episodes. In real-world practice, patients increasingly self-prescribe alternative medicines.

METHODS

We reviewed case reports, open-label, and placebo-controlled trials investigating the use of herbal medicines to treat anxiety and insomnia, and discussed their potential applications for bipolar disorder.

RESULTS

Eleven herbal medicines that have been studied in human subjects are included in this review. Mechanisms of action, efficacy, side effects, and drug-drug interactions are discussed. Based on currently available evidence, valerian seems to be the most promising candidate for insomnia and anxiety in bipolar disorder.

CONCLUSIONS

Adjunctive herbal medicines may have the potential to alleviate these symptoms and improve the outcomes of standard treatment, despite limited evidence. Physicians need to have a more in-depth understanding of the evidence of benefits, risks, and drug interactions of alternative treatments.

[Implementation of ontology-based clinical decision support system for management of interactions between antihypertensive drugs and diet]

PURPOSE

The influence of dietary composition on blood pressure is an important subject in healthcare. Interactions between antihypertensive drugs and diet (IBADD) is the most important factor in the management of hypertension. It is therefore essential to support healthcare providers' decision making role in active and continuous interaction control in hypertension management. The aim of this study was to implement an ontology-based clinical decision support system (CDSS) for IBADD management (IBADDM). We considered the concepts of antihypertensive drugs and foods, and focused on the interchangeability between the database and the CDSS when providing tailored information.

METHODS

An ontology-based CDSS for IBADDM was implemented in eight phases: (1) determining the domain and scope of ontology, (2) reviewing existing ontology, (3) extracting and defining the concepts, (4) assigning relationships between concepts, (5) creating a conceptual map with CmapTools, (6) selecting upper ontology, (7) formally representing the ontology with Protégé (ver.4.3), (8) implementing an ontology-based CDSS as a JAVA prototype application.

RESULTS

We extracted 5,926 concepts, 15 properties, and formally represented them using Protégé. An ontology-based CDSS for IBADDM was implemented and the evaluation score was 4.60 out of 5.

CONCLUSION

We endeavored to map functions of a CDSS and implement an ontology-based CDSS for IBADDM.

Use of herbal medicinal products among children and adolescents in Germany

Background

Germany is a country with a high use of herbal medicinal products. Population-based data on the use of herbal medicinal products among children are lacking. The aim of this study is to investigate the prevalence, patterns and determinants of herbal medicine use among children and adolescents in Germany.

Methods

As data base served the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), a representative population based survey conducted 2003–2006 by the Robert Koch Institute. 17,450 boys and girls aged 0–17 years provided information on drug use in the preceding seven days. Herbal medicinal products were defined according to the European and German drug laws. SPSS Complex Sample method was used to estimate prevalence rates and factors associated with herbal medicine use.

Results

The prevalence rate of herbal medicinal product use amounts to 5.8% (95% confidence interval 5.3-6.3%). Use of herbal medicine declines along with increasing age and shows no difference between boys and girls in younger age groups. Teenage girls are more likely to use herbal medicines than teenage boys. Two thirds of herbal medicines are used for the treatment of coughs and colds; nearly half of herbal medicines are prescribed by medical doctors. Determinants of herbal medicinal product use are younger age, residing in South Germany, having a poor health status, having no immigration background and coming from a higher social class family. Children’s and parents-related health behavior is not found to be associated with herbal medicine use after adjusting for social class.

Conclusions

Use of herbal medicinal products among children and adolescents between the ages of 0 and 17 years in Germany is widely spread and shows relatively higher rates compared to international data. This study provides a reference on the use of herbal medicinal products for policy-makers, health professionals and parents. Further studies are needed to investigate the effectiveness and safety of specific herbal medicinal products, potential effects of long term use as well as possible interactions of herbal medicinal products with concomitantly used conventional medicines.

Review article: Herbal hepatotoxicity--an update on traditional Chinese medicine preparations

BACKGROUND

Although evidence for their therapeutic efficacy is limited, herbal traditional Chinese medicine (TCM) preparations increasingly gain popularity. In contrast to other herbal products, adverse effects by herbal TCM including liver toxicity were rarely reported. In recent years, more cases were published, providing new clinical challenges.

AIM

To summarise comprehensively the literature on herbal TCM hepatotoxicity since 2011.

METHODS

PubMed was searched using key words related to TCM, the results were restricted to full English-language publications and abstracts published since 2011. In addition, the database of the National Institutes of Health (NIH) and LiverTox was accessed under the topic 'Drug record: Chinese and other Asian herbal medicines'.

RESULTS

Since 2011, new case reports and case series provided evidence for herbal hepatotoxicity by TCM, focusing on nine TCM herbal mixtures and four individual TCM herbs with potential health hazards. These were the TCM products Ban Tu Wan, Chai Hu, Du Huo, Huang Qin, Jia Wei Xia Yao San, Jiguja, Kamishoyosan, Long Dan Xie Gan Tang, Lu Cha, Polygonum multiflorum products, Shan Chi, 'White flood' containing the herbal TCM Wu Zhu Yu and Qian Ceng Ta, and Xiao Chai Hu Tang. Other developments include the establishment of a new and early diagnostic serum marker for hepatotoxicity caused by pyrrolizidine alkaloids, assessed using ultra performance liquid chromatography-mass spectrometry analysis, and new regulatory details to improve herbal TCM product quality and safety.

CONCLUSION

Stringent evaluation of the risk/benefit ratio is essential to protect traditional Chinese medicines users from health hazards including liver injury.

Inhibition of major drug metabolizing CYPs by common herbal medicines used by HIV/AIDS patients in Africa-- implications for herb-drug interactions

The purpose of this study was to evaluate the potential risk of common herbal medicines used by HIV-infected patients in Africa for herb-drug interactions (HDI). High throughput screening assays consisting of recombinant Cytochrome P450 enzymes (CYPs) and fluorescent probes, and parallel artificial membrane permeability assays (PAMPA) were used. The potential of herbal medicines to cause HDI was ranked according to FDA guidelines for reversible inhibition and categorization of time dependent inhibition was based on the normalized ratio. CYPs 1A2 and 3A4 were most inhibited by the herbal extracts. H. hemerocallidea (IC50 = 0.63 µg/mL and 58 µg/mL) and E. purpurea (IC50 = 20 µg/mL and 12 µg/mL) were the potent inhibitors of CYPs 1A2 and 3A4 respectively. L. frutescens and H. hemerocallidea showed clear time dependent inhibition on CYP3A4. Furthermore, the inhibitory effect of both H. hemerocallidea and L. frutescens before and after PAMPA were identical. The results indicate potential HDI of H. hemerocallidea, L. frutescens and E. purpurea with substrates of the affected enzymes if maximum in vivo concentration is achieved.

Stereoselective property of 20(S)-protopanaxadiol ocotillol type epimers affects its absorption and also the inhibition of P-glycoprotein

Stereoselectivity has been proved to be tightly related to drug action including pharmacodynamics and pharmacokinetics. (20S,24R)-epoxy-dammarane-3,12,25-triol (24R-epimer) and (20S,24S)-epoxy-dammarane-3,12,25-triol (24S-epimer), a pair of 20(S)-protopanaxadiol (PPD) ocotillol type epimers, were the main metabolites of PPD. Previous studies have shown that 24R-epimer and 24S-epimer had stereoselectivity in pharmacological action and pharmacokinetics. In the present study, the aim was to further study the pharmacokinetic characteristics of both epimers, investigate their absorption mechanism and analyze the selectivity effects of ocotillol type side chain and C24 stereo-configuration on P-glycoprotein (P-gp) in vivo and in vitro. Results showed that the absolute bioavailability of 24R-epimer was about 14-fold higher than that of 24S-epimer, and a linear kinetic characteristic was acquired in doses of 5-20 mg/kg for both epimers after oral administration. Furthermore, the apparent permeability coefficients of 24R-epimer were 5-7 folds higher than that of 24S-epimer having lower efflux ratios in Caco-2 cell models. Moreover, both 24R-epimer and 24S-epimer had similar inhibitory effects on P-gp by increasing cellular retention of rhodamine 123 in Caco-2 cells and decreasing efflux of digoxin across Caco-2 cell monolayers. In situ in vivo experiments showed that the inhibition of 24R-epimer on P-gp was stronger than that of 24S-epimer by single-pass intestinal perfusion of rhodamine 123 in rats. Western blot analyses demonstrated that both epimers had no action on P-gp expression in Caco-2 cells. In conclusion, with respect to the stereoselectivity, C24 S-configuration of the ocotillol type epimers processed a poor transmembrane permeability and could be distinguished by P-gp. Sharing a dammarane skeleton, both 24R-epimer and 24S-epimer were potent inhibitors of P-gp. This study provides a new case of stereoselective pharmacokinetics of chiral compounds which contributes to know the chiral characteristics of P-gp and structure-action relationship of PPD type and ocotillol type ginsenosides as a P-gp inhibitor.

Red clover causing symptoms suggestive of methotrexate toxicity in a patient on high-dose methotrexate

The case report discusses a very serious interaction between red clover and methotrexate not previously documented. It highlights the potential pitfalls of concomitant use of herbal remedies and conventionally prescribed drugs and the importance of advising our patients about OTC drugs. A 52-year-old woman attended her general practitioner for advice on menopausal flushing. She was on methotrexate weekly injections for severe psoriasis and was not keen to consider anything that would possibly affect her skin. Alternative therapies were discussed and red clover was suggested. This was bought OTC. After the third day of taking red clover capsules (430 mg), the patient developed severe vomiting and epigastric pain. She contacted the dermatology clinic that administers the methotrexate injection and was thought to have symptoms suggestive of methotrexate toxicity even though her liver function tests remained within normal levels. She had been receiving methotrexate injections for nearly two years with no adverse effects. The only new drug that had been started was red clover and this was thought to be the probable cause of the toxicity. It was withdrawn. The patient made a full recovery and received her next injection of methotrexate with no adverse effects. The interaction was reported to the MHRA with a yellow card.

Herbal tea extracts inhibit Cytochrome P450 3A4 in vitro

OBJECTIVES

Ciclosporin and sirolimus, two immunosuppressive agents with narrow therapeutic windows, are mainly metabolized by Cytochrome 3A4 (CYP3A4). A clinical case of toxic blood levels of these drugs after the consumption of a '24-flavours' tea was reported. This study aims to identify the causative ingredients of the 24-flavour herbal tea in the inhibition of CYP3A4 metabolism.

METHODS

Two commercially available 24-flavour tea products purchased in Hong Kong and the six plant constituents were tested for their CYP3A4 inhibitory effects utilizing an in-vitro fluorometric assay.

KEY FINDINGS

Of the commercially available teas available in Hong Kong, the most potent inhibitory effect was observed with the tea consumed in the initial clinical case. Of the six universal constituents, chrysanthemum exhibited the greatest inhibitory effect, with an IC50 of 95.7 μg/ml. Dandelion, liquorice and bishop's weed have IC50 of 140.6, 148.4 and 185.5 μg/ml, respectively. Field mint and Japanese honeysuckle have weaker inhibitory effect on CYP3A4 with IC50 of 1153.3 and 1466.3 μg/ml.

CONCLUSIONS

This study confirms the possible implication of herbal tea constituents in the inhibition of ciclosporin and sirolimus' CYP3A4 metabolism. Combined usage of herbal teas with drug should be closely monitored.

Concurrent Use of Conventional Drugs with Chinese Herbal Products in Taiwan: A Population-based Study

The increased use of Chinese herbal products (CHPs) worldwide has raised the concern of herb-drug interactions. The aim of this study was to determine the prevalence and utilization patterns of concurrent use of conventional drugs and CHPs in Taiwan. The usage and frequency of services in the co-prescription of a CHP and a conventional drug were evaluated. Subjects were recruited from a simple random sample of 1,000,000 subjects from over 22 million beneficiaries of the National Health Insurance in 2007. The logistic regression method was employed to estimate the odds ratios (ORs) for the co-prescription of a CHP and a conventional drug (CH + D) and a conventional drug alone (D-alone). The prevalence of the CH + D was 14.1%. Females, regular salary earners, and elderly (65 years and above) were more likely to consume a CHP and a conventional drug concurrently. Painkillers, especially acetaminophen, and anti-cough medicines were the top two conventional drugs that were most frequently co-prescribed with a CHP. Anti-cough medication is the most common conventional drug co-prescribed with CHP, after painkillers. We recommend that safety issues be investigated in future research and integrating both healthcare technologies may be beneficial for the overall health and quality of life of patients.

Ethnobotanical and antimicrobial study of some selected medicinal plants used in Khyber Pakhtunkhwa (KPK) as a potential source to cure infectious diseases

Background

Present investigation deals with antimicrobial screening of ten medicinally important plants used by the inhabitants of district Haripur, Khyber Pakhtunkhwa (KPK) for different infectious diseases.

Methods

Aqueous, n-hexane and ethanolic extracts of each plant were tested for their antimicrobial activity against both Gram positive and Gram negative strains of bacteria, as well as strain of yeast. Agar well diffusion and broth dilution methods were used to determine the antimicrobial activity of different plant extracts.

Results

The results indicated that all plants exhibited antimicrobial activity against one or more test pathogens. Interestingly, extracts of three plants showed strong and broad spectrum activity as compared to rest of the extracts which demonstrated the moderate activity. On the whole ethanolic extracts exhibited maximum antimicrobial effect than their corresponding aqueous and n-hexane extracts, when compared with standard antibiotics i.e., Streptomycin and Tetracycline. Among various extracts, only ethanloic extract of Azadirachta indica and aqueous and ethanolic extracts of Eucalyptus globulus and Bergenia ciliata and ethanolic extract of Punica granatum were found to have potentially promising activity against test microorganisms.

Conclusion

Different plant extracts show promising antimicrobial activity justifying their usage in traditional medicines. This study will be continued to identify more plants with potential antimicrobial components.

A systematic review and meta-analysis of herbal medicine on chronic obstructive pulmonary diseases

Herbal medicine (HM) as an adjunct therapy has been shown to be promising for the chronic obstructive pulmonary disease (COPD). However, the role of herbs in COPD remains largely unexplored. In this present study, we conducted the systematic review to evaluate the efficacy of herbs in COPD. 176 clinical studies with reporting pulmonary function were retrieved from English and Chinese database. Commonly used herbs for acute exacerbations stage (AECOPD) and stable COPD stage (SCOPD) were identified. A meta-analysis conducted from 15 high quality studies (18 publications) showed that HM as an adjunct therapy had no significant improvement in pulmonary function (FEV1, FEV%, FVC, and FEV1/FVC) compared to conventional medicine. The efficacy of the adjunct HM on improving the arterial blood gas (PaCO2 and PaO2) for AECOPD and SCOPD remains inconclusive due to the heterogeneity among the studies. However, HM as an adjunct therapy improved clinical symptoms and quality of life (total score, activity score, and impact score of St. George's Respiratory Questionnaire). Studies with large-scale and double-blind randomized controlled trials are required to confirm the role of the adjunct HM in the management of COPD.

Use of bodily sensations as a risk assessment tool: exploring people with Multiple Sclerosis' views on risks of negative interactions between herbal medicine and conventional drug therapies

Background

Most users of complementary and alternative medicine (CAM) combine it with conventional medicine. Recent risk assessment studies have shown risks of negative interactions between CAM and conventional medicine, particularly when combining herbal medicine and conventional drug therapies (CDT). Little is known about the way users consider such risks. The present paper aims to gain knowledge about this issue by exploring views on risks of negative interactions when combining herbal medicine and CDT among people with multiple sclerosis (MS).

Methods

This paper draws on a qualitative follow-up study on a survey among members of the Danish MS Society. Semi-structured, in-depth qualitative interviews were conducted with a strategic selection from the survey respondents. The study was inspired by a phenomenological approach and emerging themes were extracted from the data through meaning condensation.

Results

Four themes characterized the informants’ views on risks of negative interactions when combining herbal medicine and CDT: 1) ‘naturalness’ in herbal medicine; 2) ‘bodily sensations’ as guidelines; 3) trust in the CAM practitioner; 4) lack of dialogue with medical doctor.

Conclusions

Generally, the combination of herbal medicine and CDT was considered by the informants to be safe. In particular, they emphasized the ‘non-chemical’ nature of herbal medicine and of their own bodily sensations as warrants of safety. A trustful relation to the CAM practitioner furthermore made some of them feel safe in their use of herbal medicine and CDT in combination. The informants’ use of bodily sensations as a non-discursive risk assessment may be a relevant element in understanding these issues.

Forensic problems with the composition and content of herbal medicines

A survey of herbal medicines available for internet and over-the-counter purchase in South Australia, Australia, was conducted looking specifically at those used for 'arthritis', 'cold and flu', 'gastrointestinal', 'stress' and 'premenstrual syndrome'. 121 products consisted of 29 in the 'arthritis' category, 33 in 'cold and flu', 19 in 'gastrointestinal' 30 in 'stress' and 10 in 'premenstrual syndrome'. Twenty two (18%) of 121 products were not registered with the Australian Register of Therapeutic Goods (ARTG), despite this being a legal requirement for their sale. Of the registered products 59 (60%) of 99 had differing ingredient concentrations on the website compared to their ARTG listing. Only three of the 15 purchased products had ingredient concentrations which were consistent between the website, ARTG listing and product packaging. These findings demonstrate that it may not be possible to determine what herbal substance an individual has been exposed to prior to death and in what concentration, based on packaging from medications seized at the scene, or from examination of website data and the ARTG listing. These discrepancies may increase the problems that exist in attempting to determine what role herbal medicines may play in the mechanism of death in certain forensic cases.

Addition of propolis to irinotecan therapy prolongs survival in ehrlich ascites tumor-bearing mice

We investigated possible synergistic action of anticancer drug Irinotecan (IRI) combined with ethanolic (EEP) and water-soluble (WSDP) derivate of propolis on Swiss albino mice injected with Ehrlich ascites tumor (EAT). For survival analysis mice were administered WSDP and EEP (100 mg/kg) daily for 3 consecutive days, beginning on 3rd day after EAT cell (1×10⁶) injection. IRI was administered at a dose of 50 mg/kg on days 1, 13, and 19. We simultaneously studied peripheral white blood cell count, cell types washed from the peritoneal cavity, functional activity of macrophages from peritoneal cavity, and the level of primary DNA damage in leukocytes, kidney, and liver cells using the alkaline comet assay. Three out of 9 mice per group survived the entire duration of the experiment (90 days) in groups treated with IRI combined with WSDP and EEP. All test components increased survival of mice by 7.53% to 231.54%. Combined treatment with IRI and/or WSDP and EEP significantly decreased percentage of tumor cells in the peritoneal cavity as compared to nontreated EAT-injected mice. All treated animals had significantly higher percentage of neutrophils in the peritoneal cavity in comparison to nontreated EAT-injected mice. We observed significantly higher value of DNA damage in leukocytes of mice treated with IRI and combination of IRI and/or WSDP and EEP as compared to nontreated EAT-injected mice, while the same treatment decreased DNA damage in kidney. Our results showed that addition of propolis to IRI treatment enhanced antitumor activity of IRI and prolongs survival in EAT-bearing mice, which definitely deserve further studies to clarify the possible mechanisms of antitumor actions of combined herb-drug treatments.

Inhibitory effects of herbal constituents on P-glycoprotein in vitro and in vivo: herb-drug interactions mediated via P-gp

Modulation of drug transporters via herbal medicines which have been widely used in combination with conventional prescription drugs may result in herb-drug interactions in clinical practice. The present study was designed to investigate the inhibitory effects of 50 major herbal constituents on P-glycoprotein (P-gp) in vitro and in vivo as well as related inhibitory mechanisms. Among these herbal medicines, four constituents, including emodin, 18β-glycyrrhetic acid (18β-GA), dehydroandrographolide (DAG), and 20(S)-ginsenoside F₁ [20(S)-GF₁] exhibited significant inhibition (>50%) on P-gp in MDR1-MDCKII and Caco-2 cells. Emodin was the strongest inhibitor of P-gp (IC₅₀=9.42 μM), followed by 18β-GA (IC₅₀=21.78 μM), 20(S)-GF₁ (IC₅₀=76.08 μM) and DAG (IC₅₀=77.80 μM). P-gp ATPase activity, which was used to evaluate the affinity of substrates to P-gp, was stimulated by emodin and DAG with Km and Vmax values of 48.61, 29.09 μM and 71.29, 38.45 nmol/min/mg protein, respectively. However, 18β-GA and 20(S)-GF₁ exhibited significant inhibition on both basal and verapamil-stimulated P-gp ATPase activities at high concentration. Molecular docking analysis (CDOCKER) further elucidated the mechanism for structure-inhibition relationships of herbal constituents with P-gp. When digoxin was co-administered to male SD rats with emodin or 18β-GA, the AUC(₀₋t) and Cmax of digoxin were increased by approximately 51% and 58%, respectively. Furthermore, 18β-GA, DAG, 20(S)-GF₁ and Rh₁ at 10 μM significantly inhibited CYP3A4/5 activity, while emodin activated the metabolism of midazolam in human liver microsomes. In conclusion, four herbal constituents demonstrated inhibition of P-gp to specific extents in vitro and in vivo. Taken together, our findings provided the basis for the reliable assessment of the potential risks of herb-drug interactions in humans.

Cardioprotective Effects of Atorvastatin plus Trimetazidine in Percutaneous Coronary Intervention

Objective: To explore the effects of preoperative administration of conventional doses of atorvastatin plus trimetazidine on the myocardial injury of patients during the perioperative period of percutaneous coronary intervention (PCI).

Methodology: 475 cases of acute coronary syndrome patients before PCI were randomly divided into the control group (238 cases) and experimental group (237 cases).The control group was treated with conventional doses of atorvastatin calcium (20 mg each time, once a night), and the experimental group was treated with conventional doses of atorvastatin calcium plus trimetazidine hydrochloride (20 mg each time, tid) for 3 d. After PCI, preoperative and postoperative 24 h concentrations of serum creatine kinase MB isoenzyme (CK-MB), cardiac troponin I (cTnI) and high sensitivity C-reactive protein (hs-CRP) as well as activity of myeloperoxidase (MPO) were investigated. Left ventricular ejection fractions of the patients were then examined 4 weeks later.

Results: Postoperative 24 h cTnI concentration and elevated MPO activity of the experimental group were significantly lower than those of the control group (P <0 05). CK-MB activities and hs-CRP concentrations of the two groups did not differ significantly (P> 0 05).

Conclusion: The administration of conventional doses of atorvastatin plus trimetazidine three days before PCI is able to protect the perioperative patients from myocardial injury.

Assessment of the effects of Radix bupleuri and vinegar-baked Radix bupleuri on cytochrome 450 activity by a six-drug cocktail approach

AIM

To assess the effects of Radix Bupleuri and vinegar-baked Radix Bupleuri on cytochrome 450 activity of rats.

METHODS

Six probe drugs (caffeine, midazolam, dextromethorphan, tolbutamide, omeprazole, chlorzoxazone) were simultaneously given to rats after different dosing of Radix Bupleuri or vinegar-baked Radix Bupleuri for seven days. The plasma concentrations of the six probes were measured by high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MS) and their corresponding pharmacokinetic parameters were calculated.

RESULTS

The AUC and T1/2 of midazolam, dextromethorphan and chlorzoxazone decreased significantly (P < 0.05) in rats after different dosing of Radix Bupleuri or vinegar-baked Radix Bupleuri for seven days. Treatment of Radix Bupleuri decreased T1/2 and AUC of omeprazole, but treatment of vinegar-baked Radix Bupleuri with normal dose did not change the pharmacokinetics of omeprazole. The pharmacokinetics of tolbutamide in all vinegar-baked Radix Bupleuri-treated rats showed no statistically significant difference (P > 0.05) from that of controlled rats, however, treatment of Radix Bupleuri decreased tolbutamide T1/2. The pharmacokinetics of caffeine in all Radix Bupleuri or vinegar-baked Radix Bupleuri-treated rats showed no statistically significant difference (P > 0.05) from that of controlled rats.

CONCLUSION

The Radix Bupleuri and vinegar-baked Radix Bupleuri have different effects on the CYP2C9 and CYP2C19. Radix Bupleuri and vinegar-baked Radix Bupleuri have strong induction effects on the CYP2E1, CYP2D6 and CYP3A4, however, have no impact on CYP1A2. The reason of different therapeutic effects of Radix Bupleuri and vinegar-baked Radix Bupleuri extract may be the different effects of Radix Bupleuri and vinegar-baked Radix Bupleuri on the CYP2C9 and CYP2C19.

Liver injury induced by herbal complementary and alternative medicine

Herbal and dietary supplement use is common. Most marketed products consist of complex mixtures. Although they are perceived as safe, instances of hepatotoxicity attributable to these products underscore their potential for injury, but the exact component that is responsible for injury is difficult to discern. The lenient regulatory environment in the United States, which opens the possibility of adulteration and contamination, adds to the challenge of disease attribution. Although many different herbal and dietary supplements have been reported to cause liver injury, in the United States, products used for bodybuilding and weight loss are the most commonly implicated.

Hypericum extract WS ® 5570 for depression--an overview

OBJECTIVE

WS(®) 5570 is a Hypericum (St. John's wort) dry extract that is available as a medicinal product in coated tablets and has a marketing authorisation for the acute treatment of mild to moderate major depression in Germany.

METHODS

This article summarizes the current state of knowledge regarding the clinical efficacy and safety of WS(®) 5570.

RESULTS

In randomised, double-blind, controlled clinical trials the antidepressant effect of the drug was superior to that of the placebo and at least comparable to that of paroxetine. The beneficial effect of WS(®) 5570 is particularly pronounced with respect to the core symptoms of depression. There is evidence that the drug may also be effective in moderate to severe depression and in prophylactic continuation treatment after recovery from an acute episode.

CONCLUSIONS

WS(®) 5570 has a very favourable safety profile, with adverse event rates on one level with placebo and lower than that of synthetic antidepressants in randomised, controlled clinical trials. It may therefore also be an option for patients who do not tolerate other antidepressant drugs. Patients with polydrug treatment should nevertheless use the drug with caution, due to its potential for interactions.

Relevance of in vitro and clinical data for predicting CYP3A4-mediated herb-drug interactions in cancer patients

The use of complementary and alternative medicines (CAM) by cancer patients is increasing. Concomitant use of CAM and anticancer drugs could lead to serious safety issues in patients. CAM have the potential to cause pharmacokinetic interactions with anticancer drugs, leading to either increased or decreased plasma levels of anticancer drugs. This could result in unexpected toxicities or a reduced efficacy. Significant pharmacokinetic interactions have already been shown between St. John's Wort (SJW) and the anticancer drugs imatinib and irinotecan. Most pharmacokinetic CAM-drug interactions, involve drug metabolizing cytochrome P450 (CYP) enzymes, in particular CYP3A4. The effect of CAM on CYP3A4 activity and expression can be assessed in vitro. However, no data have been reported yet regarding the relevance of these in vitro data for the prediction of CAM-anticancer drug interactions in clinical practice. To address this issue, a literature research was performed to evaluate the relevance of in vitro data to predict clinical effects of CAM frequently used by cancer patients: SJW, milk thistle, garlic and Panax ginseng (P. ginseng). Furthermore, in clinical studies the sensitive CYP3A4 substrate probe midazolam is often used to determine pharmacokinetic interactions. Results of these clinical studies with midazolam are used to predict pharmacokinetic interactions with other drugs metabolized by CYP3A4. Therefore, this review also explored whether clinical trials with midazolam are useful to predict clinical pharmacokinetic CAM-anticancer drug interactions. In vitro data of SJW have shown CYP3A4 inhibition after short-term exposure and induction after long-term exposure. In clinical studies using midazolam or anticancer drugs (irinotecan and imatinib) as known CYP3A4 substrates in combination with SJW, decreased plasma levels of these drugs were observed, which was expected as a consequence of CYP3A4 induction. For garlic, no effect on CYP3A4 has been shown in vitro and also in clinical studies garlic did not affect the pharmacokinetics of both midazolam and docetaxel. Milk thistle and P. ginseng predominantly showed CYP3A4 inhibition in vitro. However, in clinical studies these CAM did not cause significant pharmacokinetic interactions with midazolam, irinotecan, docetaxel and imatinib. Most likely, factors as poor pharmaceutical availability, solubility and bioavailability contribute to the lack of significant clinical interactions. In conclusion, in vitro data are useful as a first indication for potential pharmacokinetic drug interactions with CAM. However, the discrepancies between in vitro and clinical results for milk thistle and P. ginseng show that clinical studies are required for confirmation of potential interactions. At last, midazolam as a model substrate for CYP3A4, has convincingly shown to correctly predict clinical interactions between CAM and anticancer drugs.

Knowledge, attitude, and practices toward ayurvedic medicine use among allopathic resident doctors: A cross-sectional study at a tertiary care hospital in India

Context:

Ayurveda is most commonly practiced form of complementary and alternative medicine (CAM) in India. There are very few studies showing the knowledge, attitude, and practices (KAP) of allopathic doctors about Ayurvedic drugs and its use.

Aims:

The study was initiated to assess KAP toward Ayurvedic medicine use among allopathic resident doctors.

Settings and Design:

Cross-sectional and prospective study.

Materials and Methods:

After obtaining permission from the Institutional Ethics Committee, allopathic resident doctors from clinical departments were approached personally. They were given pre-formed validated questionnaire to assess KAP toward Ayurvedic medicine use.

Statistical Analysis Used:

Descriptive statistics.

Results:

Allopathic residents had little knowledge about basic concepts of Ayurveda, that is, ‘panchakarma’ and ‘tridosha’. Majority residents (99%) had no opportunity to learn basics of Ayurveda, but 67% residents prescribed Ayurvedic medicines to patients. However, many residents (76%) mentioned that cross practice should not be allowed due to lack of knowledge. One resident knew that cross-practice was not allowed by law. The commonly prescribed proprietary Ayurvedic medicines were Liv-52 (39%), Shatavari (13%), Cystone (12%) and common ailments for which these medicines prescribed were liver disorders (34%), arthritis (18%), cough and cold (13%), kidney stones (11%), and piles (10%). Nearly 76% residents felt incorporation of Ayurveda with modern medicine would attract more patients and at the same time most residents (92%) agreed that Ayurvedic medicines need scientific testing before use. Though 50% of the residents agreed for voluntary training in Ayurveda, 80% denied compulsory training. Nearly 63% residents recommended Ayurveda among all CAMs. Most of residents heard of Ayurveda from their colleagues.

Conclusions:

This study reveals that allopathic resident doctors had little knowledge about Ayurveda and Ayurvedic medicine use but engaged in prescription of Ayurvedic medicines. So some interventions should be taken to increase the knowledge and awareness of allopathic resident doctors about Ayurvedic medicine use.

A systematic approach to evaluate herb-drug interaction mechanisms: investigation of milk thistle extracts and eight isolated constituents as CYP3A inhibitors

Despite increasing recognition of potential untoward interactions between herbal products and conventional medications, a standard system for prospective assessment of these interactions remains elusive. This information gap was addressed by evaluating the drug interaction liability of the model herbal product milk thistle (Silybum marianum) with the CYP3A probe substrate midazolam. The inhibitory effects of commercially available milk thistle extracts and isolated constituents on midazolam 1'-hydroxylation were screened using human liver and intestinal microsomes. Relative to vehicle, the extract silymarin and constituents silybin A, isosilybin A, isosilybin B, and silychristin at 100 μM demonstrated >50% inhibition of CYP3A activity with at least one microsomal preparation, prompting IC50 determination. The IC50s for isosilybin B and silychristin were ∼60 and 90 μM, respectively, whereas those for the remaining constituents were >100 μM. Extracts and constituents that contained the 1,4-dioxane moiety demonstrated a >1.5-fold shift in IC50 when tested as potential mechanism-based inhibitors. The semipurified extract, silibinin, and the two associated constituents (silybin A and silybin B) demonstrated mechanism-based inhibition of recombinant CYP3A4 (KI, ∼100 μM; kinact, ∼0.20 min(-1)) but not microsomal CYP3A activity. The maximum predicted increases in midazolam area under the curve using the static mechanistic equation and recombinant CYP3A4 data were 1.75-fold, which may necessitate clinical assessment. Evaluation of the interaction liability of single herbal product constituents, in addition to commercially available extracts, will enable elucidation of mechanisms underlying potential clinically significant herb-drug interactions. Application of this framework to other herbal products would permit predictions of herb-drug interactions and assist in prioritizing clinical evaluation.

Baicalin pharmacokinetic profile of absorption process using novel in-vitro model: cytochrome P450 3A4-induced Caco-2 cell monolayers combined with rat intestinal rinse fluids

Objectives

This study was designed to investigate baicalin (BG) pharmacokinetic profile in absorption process using a new model and evaluate the potentiality as a new model.

Methods

The effects of BG on intestinal cytochrome P450 3A4 (CYP3A) protein/mRNA expression, activity and permeability glycoprotein (P-gp) were evaluated in CYP3A4-induced Caco-2 cell monolayers or rats. Intestinal rinse fluids (IF) were obtained from rat were added to modified Caco-2 monolayers.

Key findings

Orally administered BG (7 days pretreatment) inhibited intestinal CYP3A activity and protein expression. Baicalein (B) converted from BG by IF was detected in the upper jejunum in a portion-dependent manner. Subsequently, most BG were converted to B in the caecum. In modified Caco-2 monolayers, BG exhibited no effect on CYP3A4 activity or mRNA, whereas B and BG treated with IF inhibited CYP3A4 transcription and activity.

Conclusions

Intestinal CYP3A was inhibited following oral administration of BG to rat. Correspondingly, BG-mediated CYP3A inhibition was shown in vitro using modified Caco-2 monolayers treated with IF. Hence, in-vivo intestinal absorption pharmacokinetic was reproduced in vitro. IF is a key determinant of intestinal absorption, and it facilitated inhibition of CYP3A by B, not BG.