Pierre Duez

Pharmacovigilance practice and risk control of Traditional Chinese Medicine drugs in China: current status and future perspective

ETHNOPHARMACOLOGICAL RELEVANCE Traditional Chinese Medicine (TCM), including Traditional Chinese Medicine drugs (TCM drugs), has been playing a very important role in health protection and disease control for thousands of years in China. Relying on natural products, mainly of herbal origin, used either as raw materials for decoction, as prepared herbal medicines or as formulated traditional medicines, TCM is still widely accepted by Chinese people, especially for chronic diseases treatment. This extensive use warrants safety measures and so TCM drug safety monitoring and risk management are becoming increasingly important tasks for the Chinese State Food and Drug Administration (SFDA). METHODS The Adverse Drug Reaction (ADR) monitoring system in China was established both for western and TCM drugs in 1989 as a voluntary reporting system with a National Center collecting and compiling reports. Serious or multi-case reports on individual TCM drug or formulated products are detailed in the Chinese ADR Information Bulletin to inform the public and Drug Administrative authorities for risk management. RESULTS About 10-15% of the ADR reports received by the National Center are related to TCM drugs and mainly pertaining to the formulated products. In certain cases, the suspension of a particular TCM preparation is decided by SFDA China. CONCLUSION The model of safety monitoring and risk management of TCM drugs is still under exploration. Indeed, the characteristics and risk factors associated with these drugs require both proper understanding and control of the risk by strengthening standardization of clinical applications, basic science research, quality control in manufacturing, exploration of the actives monitoring methodology and enhancement of international communication and cooperation.

The Formation of Biofilms by Pseudomonas aeruginosa: A Review of the Natural and Synthetic Compounds Interfering with Control Mechanisms

P. aeruginosa is an opportunistic pathogenic bacterium responsible for both acute and chronic infections. Beyond its natural resistance to many drugs, its ability to form biofilm, a complex biological system, renders ineffective the clearance by immune defense systems and antibiotherapy. The objective of this report is to provide an overview (i) on P. aeruginosa biofilm lifestyle cycle, (ii) on the main key actors relevant in the regulation of biofilm formation by P. aeruginosa including QS systems, GacS/GacA and RetS/LadS two-component systems and C-di-GMP-dependent polysaccharides biosynthesis, and (iii) finally on reported natural and synthetic products that interfere with control mechanisms of biofilm formation by P. aeruginosa without affecting directly bacterial viability. Concluding remarks focus on perspectives to consider biofilm lifestyle as a target for eradication of resistant infections caused by P. aeruginosa.

The flavanone naringenin reduces the production of quorum sensing-controlled virulence factors in Pseudomonas aeruginosa PAO1

Preliminary screening of the Malagasy plant Combretum albiflorum for compounds attenuating the production of quorum sensing (QS)-controlled virulence factors in bacteria led to the identification of active fractions containing flavonoids. In the present study, several flavonoids belonging to the flavone, flavanone, flavonol and chalcone structural groups were screened for their capacity to reduce the production of QS-controlled factors in the opportunistic pathogen Pseudomonas aeruginosa (strain PAO1). Flavanones (i.e. naringenin, eriodictyol and taxifolin) significantly reduced the production of pyocyanin and elastase in P. aeruginosa without affecting bacterial growth. Consistently, naringenin and taxifolin reduced the expression of several QS-controlled genes (i.e. lasI, lasR, rhlI, rhlR, lasA, lasB, phzA1 and rhlA) in P. aeruginosa PAO1. Naringenin also dramatically reduced the production of the acylhomoserine lactones N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL), which is driven by the lasI and rhlI gene products, respectively. In addition, using mutant strains deficient for autoinduction (ΔlasI and ΔrhlI) and LasR- and RhlR-based biosensors, it was shown that QS inhibition by naringenin not only is the consequence of a reduced production of autoinduction compounds but also results from a defect in the proper functioning of the RlhR-C4-HSL complex. Widely distributed in the plant kingdom, flavonoids are known for their numerous and determinant roles in plant physiology, plant development and in the success of plant-rhizobia interactions, but, as shown here, some of them also have a role as inhibitors of the virulence of pathogenic bacteria by interfering with QS mechanisms.

Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydroguanine/8-oxo-7,8-dihydro-2 '-deoxyguanosine in DNA

The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG for analysis. About half the results returned (for 8-oxodG) were within 20% of the median values. Coefficients of variation (for three identical samples) were commonly around 10%. A sample of calf thymus DNA was sent, dry, to all laboratories. Analysis of 8-oxoGua/8-oxodG in this sample was a test of hydrolysis methods. Almost half the reported results were within 20% of the median value, and half obtained a CV of less than 10%. In order to test sensitivity, as well as precision, DNA was treated with photosensitiser and light to introduce increasing amounts of 8-oxoGua and samples were sent to members. Median values calculated from all returned results were 45.6 (untreated), 53.9, 60.4 and 65.6 8-oxoGua/10 6 Gua; only seven laboratories detected the increase over the whole range, while all but one detected a dose response over two concentration intervals. Results in this trial reflect a continuing improvement in precision and accuracy. The next challenge will be the analysis of 8-oxodG in DNA isolated from cells or tissue, where the concentration is much lower than in calf thymus DNA.

Organocatalysis Paradigm Revisited: Are Metal-Free Catalysts Really Harmless?

Catalysts are commonly used in polymer synthesis. Traditionally, catalysts used to be metallic compounds but some studies have pointed out their toxicity for human health and environment, and the removal of metal impurities from synthetic polymer is quite expensive. Organocatalysts have been intensively synthesized and are now widely used in ring-opening polymerization (ROP) reactions to address these issues. However, for most of them, there is not any evidence of their safety. The present study attempts to assess whether well-established organo-based ROP catalysts used for the preparation of FDA-approved polyesters may present a certain level of cytotoxicity. In vitro toxicity is evaluated using a methyl-thiazol-tetrazolium cytotoxicity assay on two cell models (FHs74Int and HepaRG). Among the investigated organocatalysts, only functionalized thiourea shows an important cytotoxicity on both cell models. 4-Dimethylaminopyridine (DMAP), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and meta-(trimethylammonio)phenolate betaine (m-BE) show cytotoxicity against HepaRG cell line only at a high concentration.

The quest for modernisation of traditional Chinese medicine

Traditional Chinese medicine (TCM) is an integral part of mainstream medicine in China. Due to its worldwide use, potential impact on healthcare and opportunities for new drug development, TCM is also of great international interest. Recently, a new era for modernisation of TCM was launched with the successful completion of the Good Practice in Traditional Chinese Medicine Research in the Post-genomic Era (GP-TCM) project, the European Union’s Seventh Framework Programme (FP7) coordination action on TCM research. This 3.5-year project that involved inputs from over 200 scientists resulted in the production of 20 editorials and in-depth reviews on different aspects of TCM that were published in a special issue of Journal of Ethnopharmacology (2012; volume 140, issue 3). In this narrative review, we aim to summarise the findings of the FP7 GP-TCM project and highlight the relevance of TCM to modern medicine within a historical and international context. Advances in TCM research since the 1950s can be characterised into three phases: Phase I (1950s-1970s) was fundamental for developing TCM higher education, research and hospital networks in China; Phase II (1980s-2000s) was critical for developing legal, economic and scientific foundations and international networks for TCM; and Phase III (2011 onwards) is concentrating on consolidating the scientific basis and clinical practice of TCM through interdisciplinary, interregional and intersectoral collaborations. Taking into account the quality and safety requirements newly imposed by a globalised market, we especially highlight the scientific evidence behind TCM, update the most important milestones and pitfalls, and propose integrity, integration and innovation as key principles for further modernisation of TCM. These principles will serve as foundations for further research and development of TCM, and for its future integration into tomorrow’s medicine.

A validation protocol for the HPTLC standardization of herbal products: application to the determination of acteoside in leaves of Plantago palmata Hook. f.s.

Formal validation, that is the study of the analytical performances of a method, is recognized as the best safeguard against the generation and publication of data with low reliability. Although the topic of HPTLC validations has been largely investigated, there is still a need for a general validation method applicable whenever a blank matrix cannot be reconstituted, notably herbs and their extracts. This work proposes two validation schemes aiming at generate linearity, accuracy and precision data in a minimal number of HPTLC plates, taking the standardization of Plantago palmata as an example with both UV and visible (post-chromatographic derivatization with a sulphuric acid-vanillin reagent) detections. A major problem associated with HPTLC determinations is underlined, namely the low range of linearity which makes spiking studies quite difficult as care must be taken to avoid overloading, whereas keeping the analyte detectable in blank extracts and avoiding spikes too close to endogenous levels. A second problem is the use of general post-chromatographic derivatization reagents that compromise the selectivity of the method by reacting with compounds that may not be resolved from the compound of interest. The use of such reagents is clearly not without danger, especially given the relatively low resolution of planar chromatography. In conclusion, the retained validation protocol effectively yields the main validation data whereas allowing to pinpoint major analytical drawbacks. It was not possible to simultaneously validate aucubin and acteoside assays as both analytes are present at too different levels/detectabilities.

Changes in the phenolic and lipophilic composition, in the enzyme inhibition and antiproliferative activity of Ficus carica L. cultivar Dottato fruits during maturation

Fruits of Ficus carica cultivar Dottato from Italy were examined to assess how the stage of ripeness influences their chemical composition, antioxidant activity, pancreatic lipase inhibition and antiproliferative properties on C32 melanoma cells. Fruits of the first harvest (June) showed a major content in furanocoumarins and pyranocoumarins whereas the fruits collected in September showed the highest polyphenolic content (11.9 mg/g of dried material). The total 70% ethanol extracts were portioned between methanol/water and n-hexane, dichloromethane and ethyl acetate, successively. Coumarins and fatty acid esters were the most abundant components of the n-hexane fractions. The dichloromethane fractions showed as major components 2 furanocoumarins (rutarenin and pimpinellin). The total extracts of F. carica cv. Dottato exhibited a significant dose-dependent antiradical and inhibition of lipid peroxidation activity, particularly fruits of the first harvest (June) that showed the highest activity with IC50 of 1.64 mg/mL and 0.004 mg/mL, respectively. Among single fractions, the ethyl acetate fraction from the second harvest (July) showed the highest antiradical activity with an IC50 value of 0.05 mg/mL while the dichloromethane fraction showed the best inhibition of lipid peroxidation with an IC50 value of 0.02 mg/mL. Dichloromethane fractions showed the highest photodynamic cytotoxicity with an IC50<5 μg/mL.

Protective effect of Moringa oleifera leaves against gentamicin-induced nephrotoxicity in rabbits.

Oxidative stress due to abnormal production of reactive oxygen species has been implicated in the nephrotoxicity induced by gentamicin. The nephroprotective effect of aqueous-ethanolic extract of Moringa oleifera leaves (150 and 300 mg/kg) was evaluated against gentamicin-induced (80 mg/kg) renal injury in rabbits. Serum urea and creatinine levels were evaluated as the markers of renal nephrotoxicity. At the end of the experiment, the kidneys of rabbits were excised for histological examinations and determination of lipid peroxidation levels. Serum urea and creatinine levels were reduced in the M. oleifera (150 and 300 mg/kg) plus gentamicin treated groups. On histological examinations, kidney of intoxicated rabbits groups which received M. oleifera extract showed reparative tendencies. A highly significant (p < 0.01) elevation was observed in lipid peroxidation (LPO) level in the kidneys of gentamicin-intoxicated rabbits whereas combined treatment of M. oleifera and gentamicin group showed a highly significant (p < 0.01) depletion in LPO. The present study indicates that aqueous-ethanolic extract of M. oleifera leaves attenuates renal injury in rabbits treated with gentamicin, possibly by inhibiting lipid peroxidation.

Inhibition of myeloperoxidase activity by the alkaloids of Peganum harmala L. (Zygophyllaceae)

ETHNOPHARMACOLOGICAL RELEVANCE Seeds and aerial parts of Peganum harmala L. are widely used in Algeria as anti-inflammatory remedies. Evaluation of Peganum harmala total alkaloids extracts and pure β-carboline compounds as an anti-inflammatory treatment by the inhibition of an enzyme key of inflammatory, myeloperoxidase (MPO) and HPLC quantification of the alkaloids from the different parts of plant. MATERIALS AND METHODS MPO inhibition was tested using taurine chloramine test. The inhibition of LDL oxidation induced by MPO was carried out. The molecular docking analysis of Peganum harmala alkaloids on MPO was performed using the Glide XP docking protocol and scoring function and the redox potential of alkaloids was determined using an Epsilon potentiostat. The concentration of harmala alkaloids was determined using HPLC analysis. RESULTS The HPLC profiling of the active total alkaloids indicates that β-carboline e.g. harmine, harmaline, harmane, harmol and harmalol are major components. As β-carbolines resemble tryptamine, of which derivatives are efficient inhibitors of MPO, the harmala alkaloids were tested for their activity on this enzyme. Total alkaloids of the seeds and of the aerial parts strongly inhibited MPO at 20µg/mL (97±5% and 43±4%, respectively) whereas, at the same concentration, those of the roots showed very low inhibition (15±6%). Harmine, harmaline and harmane demonstrated a significant inhibition of MPO at IC50 of 0.26, 0.08 and 0.72µM respectively. These alkaloids exerted a similar inhibition effects on MPO-induced LDL oxidation. Molecular docking analysis of Peganum harmala alkaloids on MPO showed that all active Peganum harmala alkaloids have a high affinity on the active site of MPO (predicted free energies of binding up to -3.1kcal/mol). Measurement of redox potentials versus the normal hydrogen electrode clearly differentiated (i) the high MPO inhibitory activity of harmine, harmaline and harmane (+1014, 1014 and 1003mV, respectively); and (ii) the low activity of harmalol and harmol (+629/778 and 532/644mV, respectively). A reverse phase HPLC method has been developed to determine simultaneously five alkaloids of Peganum harmala. Seeds contained all five β-carboline derivatives with the main active alkaloids, harmaline and harmine, being up to 3.8% and 2.9%, respectively. Up to 3.2% of harmine was determined in the roots. The four β-carboline derivatives, harmine, harmaline, harmane and harmalol were identified in the aerial parts. The highest inhibitory effect observed in seeds and the moderate effect of aerial parts could be explained by their harmine and harmaline content. In contrast, the very weak inhibition of the root extract, despite the presence of harmine, may tentatively be explained by the high concentration of harmol which can reduce Compound II of MPO to the native form. CONCLUSION The inhibition of MPO by Peganum harmala β-carboline alkaloids, herein reported for the first time, may explain the anti-inflammatory effect traditionally attributed to its herbal medicine.