Zhong Zuo

Danshen: an overview of its chemistry, pharmacology, pharmacokinetics, and clinical use.

Danshen, the dried root of Salvia miltiorrhiza, has been widely used in China and, to a lesser extent, in Japan, the United States, and other European countries for the treatment of cardiovascular and cerebrovascular diseases. In China, the specific clinical use is angina pectoris, hyperlipidemia, and acute ischemic stroke. The current review covers its traditional uses, chemical constituents, pharmacological activities, pharmacokinetics, clinical applications, and potential herb‐drug interactions based on information obtained in both the English and Chinese literature. Although numerous clinical trials have demonstrated that certain Danshen products in China are effective and safe for the treatment of cardiovascular diseases, most of these lack sufficient quality. Therefore, large randomized clinical trials and further scientific research to determine its mechanism of actions will be necessary to ensure the safety, effectiveness, and better understanding of its action.

Pharmacological effects and pharmacokinetics properties of Radix Scutellariae and its bioactive flavones

Radix Scutellariae is the dried root of the medicinal plant Scutellariae baicalensis Georgi. It exhibits a variety of therapeutic effects and has a long history of application in traditional formulations as well as in modern herbal medications. It has been confirmed that flavonoids are the most abundant constituents and induce these therapeutic effects. Six flavones are proven to be the major bioactive flavones in Radix Scutellariae existing in the forms of aglycones (baicalein, wogonin, oroxylin A) and glycosides (baicalin, wogonoside, oroxylin A-7-glucuronide). All six flavones are pharmacologically active and show great potential in the treatment of inflammation, cancers and virus-related diseases. The current review covers the preparation of the herb Radix Scutellariae, quantification of its major bioactive ingredients, and pharmacological effects of the proposed six bioactive flavones. In addition, this review summarizes the pharmacokinetic profiles of the bioactive flavones reported so far that could be used for further improvement of their pharmacokinetic study. Moreover, due to abundant co-occurring bioactive components in Radix Scutellariae, our review further documents the pharmacokinetic interactions among them.

Discovery of Molecular Mechanisms of Traditional Chinese Medicinal Formula Si-Wu-Tang Using Gene Expression Microarray and Connectivity Map

To pursue a systematic approach to discovery of mechanisms of action of traditional Chinese medicine (TCM), we used microarrays, bioinformatics and the “Connectivity Map” (CMAP) to examine TCM-induced changes in gene expression. We demonstrated that this approach can be used to elucidate new molecular targets using a model TCM herbal formula Si-Wu-Tang (SWT) which is widely used for womens health. The human breast cancer MCF-7 cells treated with 0.1 µM estradiol or 2.56 mg/ml of SWT showed dramatic gene expression changes, while no significant change was detected for ferulic acid, a known bioactive compound of SWT. Pathway analysis using differentially expressed genes related to the treatment effect identified that expression of genes in the nuclear factor erythroid 2-related factor 2 (Nrf2) cytoprotective pathway was most significantly affected by SWT, but not by estradiol or ferulic acid. The Nrf2-regulated genes HMOX1, GCLC, GCLM, SLC7A11 and NQO1 were upreguated by SWT in a dose-dependent manner, which was validated by real-time RT-PCR. Consistently, treatment with SWT and its four herbal ingredients resulted in an increased antioxidant response element (ARE)-luciferase reporter activity in MCF-7 and HEK293 cells. Furthermore, the gene expression profile of differentially expressed genes related to SWT treatment was used to compare with those of 1,309 compounds in the CMAP database. The CMAP profiles of estradiol-treated MCF-7 cells showed an excellent match with SWT treatment, consistent with SWTs widely claimed use for womens diseases and indicating a phytoestrogenic effect. The CMAP profiles of chemopreventive agents withaferin A and resveratrol also showed high similarity to the profiles of SWT. This study identified SWT as an Nrf2 activator and phytoestrogen, suggesting its use as a nontoxic chemopreventive agent, and demonstrated the feasibility of combining microarray gene expression profiling with CMAP mining to discover mechanisms of actions and to identify new health benefits of TCMs.

Pharmacokinetics and Modeling of Quercetin and Metabolites

PurposeTo determine the pharmacokinetics of quercetin and its glucuronide/sulfate conjugates and to develop a pharmacokinetic model to simultaneously describe their disposition after intravenous and oral administration in rats.MethodsAfter oral, intraportal, and intravenous administration of quercetin, serial plasma, urine, and fecal concentrations of quercetin and its conjugates were determined by an HPLC method. Enterohepatic recirculation was evaluated in a linked-rat model as well as after oral administration of bile containing quercetin and its metabolites. Based on the experimental data, a specific compartmental model was developed and validated to describe and predict the plasma concentration-time profiles of quercetin and its conjugates after oral and intravenous administration.ResultsOnly 5.3% of unchanged quercetin was bioavailable, although the total quercetin absorbed was as high as 59.1%. After oral administration, about 93.3% of quercetin was metabolized in the gut, with only 3.1% metabolized in the liver. No significant enterohepatic recirculation was observed for both quercetin and its conjugated metabolites. The pharmacokinetic model fitted well the observed data of quercetin and its conjugates.ConclusionsOur study clarifies the relative importance of the gut, liver, and bile in the metabolism and excretion of quercetin and its conjugates. The pharmacokinetic model appears to be suitable for describing the absorption and disposition of the quercetin and its conjugates and may be applicable to other flavonoids that undergo similar pharmacokinetic pathways.

Involvement of UDP-glucuronosyltransferases in the extensive liver and intestinal first-pass metabolism of flavonoid baicalein.

PurposeThe present study aims to investigate the involvement of UDP-glucuronosyltranferase (UGT) in the extensive liver and intestinal first-pass glucuronidation of baicalein (B) in both rats and humans and also to study sulfation and P450 mediated hydroxylation of B.Materials and MethodsB was incubated with liver and intestine microsome, cytosol, S9 fractions from human, rat and various human recombinant UGT isozymes, respectively. The generated metabolites were identified by HPLC/MS/MS and quantified by HPLC/UV.ResultsThree metabolites of B namely baicalein 7-O-glucuronide (BG), the isomer of baicalein 7-O-glucuronide (BG’), and baicalein sulfate were found. BG, the predominant metabolite of B, was extensively generated in liver and jejunum microsomes in both humans and rats. Its formation was mainly catalyzed by UGT 1A9 and also mediated by UGT 1A1, 1A3, 1A8, 1A7 and 2B15 with different kinetic profiles. UGT 1A8 mediated formation of BG’ was mainly found in human intestine and rat liver microsomes. Sulfation and P450 mediated hydroxylation of B were much less significant than glucuronidation.ConclusionsExtensive liver and intestinal first-pass glucuronidation of B were found in both humans and rats. Under the current experimental conditions, UGT 1A9 and UGT 1A8 demonstrated the fastest formation rate of BG in human liver preparations and BG’ in human intestine preparations, respectively.

Radix Puerariae: An overview of Its Chemistry, Pharmacology, Pharmacokinetics, and Clinical Use

Radix Puerariae has been traditionally used for the treatment of diarrhea, acute dysentery, deafness and cardiovascular diseases. Yege (Gegen or Radix Puerariae lobatae), the dried root of Pueraria lobata (Wild.) Ohwi, has been widely used in China and, to a lesser extent, in Japan, Korea, and the United States. Although they have been classified into different categories in Chinese Pharmacopoeia, Yege is often used interchangeably in practice with Fenge (Radix Puerariae thomsonii), which is the dried root of Pueraria thomsonii Benth. Among various commercially available products of Radix Puerariae, injection of puerarin, the major isoflavone from Radix Puerariae, has been most widely used as a vasodilator for the treatment of angina and myocardial infarction. Considering the extensive clinical usage and recent alert of fatal herb–drug interaction of Radix Puerariae, the current review is proposed to cover its traditional applications, pharmacological activities, pharmacokinetics, clinical efficacy, and potential herb–drug interactions aiming to fill in the information gaps of this herb for frontline practitioners. Although various small, poorly designed clinical trials have demonstrated the safety, efficacy, and significant clinical benefits of Radix Puerariae, prospective randomized controlled clinical trials are needed to further establish its effective and safe use.

Simultaneous quantification of active components in the herbs and products of Si-Wu-Tang by high performance liquid chromatography―mass spectrometry

Si-Wu-Tang (SWT), comprising Paeoniae, Angelicae, Chuanxiong and Rehmanniae, is one of the most popular Traditional Chinese Medicine (TCM) formulae for womans health. Data mining from the available Chinese and English literatures indicated that the major bioactive components of SWT consist of paeoniflorin, paeonol, gallic acid, ferulic acid, Z-ligustilide, ligustrazine, butylphthalide, senkyunolide A and catalpol. Since content determination of the marker compounds is generally considered as an initial step for quality control of TCM product, a high performance liquid chromatography-mass spectrometric method employing both positive and negative electrospray ionization was developed for the simultaneous determination of the nine identified compounds in the raw herbs and products of SWT. The LOQ of the developed assay method for the tested components was 10ng/ml for ligustrazine, 200ng/ml for catalpol, and 100ng/ml for the other seven compounds. The intra-day and inter-day variations of the current assay were within 17.5%. Paeoniflorin, ferulic acid, gallic acid, Z-ligustilide and senkyunolide A were found in all SWT products investigated. Variations in the contents of the studied compounds were observed among batches of raw herbs and SWT products. The currently developed method provides a sensitive and rapid quantification approach that can be useful in the quality control of raw herbs and products of SWT.

High-performance liquid chromatographic method for simultaneous determination of hawthorn active components in rat plasma

A simple HPLC method with photodiode-array (PDA) ultraviolet detection was developed for the simultaneous determination of four active polyphenol components of hawthorn (Crataegus), chlorogenic acid, epicatechin, hyperoside and isoquercitrin, in rat plasma. Following extraction from the plasma samples with ethyl acetate-methanol (2:1, v/v), these four compounds were successfully separated using a C18 column with a gradient elution of 5 and 25% acetonitrile in 25 mM phosphate buffer (pH 2.4). The flow-rate was set at 1 ml/min and the eluent was detected at 325 nm for chlorogenic acid, 278 nm for epicatechin, and 360 nm for both hyperoside and isoquercitrin. Narignin (0.82 microg) was used as the internal standard and was detected at 278 nm. The method is linear over the studied range of 0.16-40, 0.63-160, 0.13-32 and 0.13-30 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin, respectively. The correlation coefficient for each analyte was greater than 0.995. The intra-day and inter-day precision of the analysis was better than 4 and 7%, respectively. The extraction recoveries at low to high concentration were greater than 85% for both epicatechin and chlorogenic acid, and greater than 94% for both hyperoside and isoquercitrin. The detection limits were 0.04, 0.20, 0.03 and 0.03 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin. The developed method was used to analyze the plasma concentrations of the four analytes after the intravenous administration of hawthorn polyphenol extract to rats.

Contents of major bioactive flavones in proprietary traditional Chinese medicine products and reference herb of radix Scutellariae.

A simple and efficient HPLC/UV method for the simultaneous determination of six bioactive flavones, namely baicalein, baicalin, wogonin, wogonoside, oroxylin A and oroxylin A-7-O-glucuronide, has been developed and applied for their content determination in reference herb and proprietary traditional Chinese medicine (PTCM) products of radix Scutellariae. The chromatographic separation was carried out on a Thermo C(18) column and linear gradient elution was employed with a mobile phase containing acetonitrile and 20 mM sodium dihydrogen phosphate buffer (pH 4.6). All the analytes were detected by PDA detector at a wavelength of 270 nm. Contents of the analytes in radix Scutellariae containing PTCM products in forms of capsule, soft capsule, tablet and dripping pill and the reference herb of radix Scutellariae were analyzed by sonicator extraction with methanol and water mixture (80:20) containing 1 mM HCl for 30 min followed by HPLC analysis. Separation of the six analytes was achieved within 25 min with good linearity (R(2)>0.99). The R.S.D. of both the intra-day and inter-day precision for all the six analytes was below 10.14%. The accuracy at different concentrations was within the range of -7.83 to 4.06%. The extraction recovery was within the range of 89.22-107.33% for all the analytes. Contents of the six flavones were found to vary significantly among different products with glycosides, such as baicalin, wogonoside and oroxylin A-7-O-glucuronide, in much greater quantity than their corresponding aglycones. In addition to baicalin (18.54+/-0.71%, w/w), the commonly used marker compound for radix Scutellariae, wogonoside (3.54+/-0.18%, w/w) and oroxylin A-7-O-glucuronide (2.84+/-0.14%, w/w) also existed in abundant amount in the reference herb. Our findings suggested that wogonoside and oroxylin A-7-O-glucuronide should also be served as the chemical markers together with baicalin for the quality control of herbs and PTCM products of radix Scutellariae.

Updates on the Clinical Evidenced Herb-Warfarin Interactions

Increasing and inadvertent use of herbs makes herb-drug interactions a focus of research. Concomitant use of warfarin, a highly efficacious oral anticoagulant, and herbs causes major safety concerns due to the narrow therapeutic window of warfarin. This paper presents an update overview of clinical findings regarding herb-warfarin interaction, highlighting clinical outcomes, severity of documented interactions, and quality of clinical evidence. Among thirty-eight herbs, Cannabis, Chamomile, Cranberry, Garlic, Ginkgo, Grapefruit, Lycium, Red clover, and St. Johns wort were evaluated to have major severity interaction with warfarin. Herbs were also classified on account of the likelihood of their supporting evidences for interaction. Four herbs were considered as highly probable to interact with warfarin (level I), three were estimated as probable (level II), and ten and twenty-one were possible (level III) and doubtful (level IV), respectively. The general mechanism of herb-warfarin interaction almost remains unknown, yet several pharmacokinetic and pharmacodynamic factors were estimated to influence the effectiveness of warfarin. Based on limited literature and information reported, we identified corresponding mechanisms of interactions for a small amount of “interacting herbs.” In summary, herb-warfarin interaction, especially the clinical effects of herbs on warfarin therapy should be further investigated through multicenter studies with larger sample sizes.