Presence Of Coumarin Research Articles

Coumarin-poly(2-oxazoline)s as synergetic and protein-undetected nanovectors for photodynamic therapy

Because of the difficult challenges of nanopharmaceutics, the development of a variety of nanovectors is still highly desired. Photodynamic therapy, which uses a photosensitizer to locally produce reactive oxygen species to kill the undesired cells, is a typical example for which encapsulation has been shown to be beneficial. The present work describes the use of coumarin-functionalized polymeric nanovectors based on the self-assembly of amphiphilic poly(2-oxazoline)s. Encapsulation of pheophorbide a, a known PDT photosensitizer, is shown to lead to an increased efficiency compared to the un-encapsulated version. Interestingly, the presence of coumarin both enhances the desired photocytotoxicity and enables the crosslinking of the vectors. Various nanovectors are examined, differing by their size, shape and hydrophilicity. Their behaviour in PDT protocols on HCT-116 cells monolayers is described, the influence of their crosslinking commented. Furthermore, the formation of a protein corona is assessed.

THE PHENOLIC PROFILE OF RAPESEED HONEY ENRICHED WITH MELILOTUS ALBUS FLOWERS AND ITS INHIBITORY EFFECT ON RAT PLATELET AGGREGATION

Background. The Melilotus plants are highly valued in herbal medicine, recommended for the prevention and treatment of thrombotic vein inflammation and varicose veins. Their health-promoting properties primarily result from the presence of coumarin and its derivatives. The aim of the study was to determine whether honey enriched with dried Melilotus albus flowers has the ability to inhibit platelet aggregation. The inhibitory activity of rapeseed honey (control sample), rapeseed honey enriched with 1 % w/w of M. albus dried flowers and pure coumarin were evaluated against ADP (5 µМ) and collagen (2 µg/ml) in duced aggregation of rat platelets. Platelet aggregation was measured by the turbidimetric method. Moreo ver, the quantitative polyphenolic profile determined using HPLC-PDA and volatile compounds profiles obtained by GC-MS methods for rapeseed and M. albus enriched honey were compared to identify the chemical factors that limit platelet aggregation. Results and conclusions. A beneficial, dose-dependent effect of enriched honey on the inhibition of the aggregation process was demonstrated, and for the highest concentration used (20 %), the inhibition of aggregation induced by ADP and collagen amounted to 75 % and 90%, respectively. A weaker inhibitory effect was found for pure rapeseed honey at 20 % concentration – 40 % and 55 % of inhibition, respective ly and pure coumarin (0.5 mg/ml) – 44 % and 20 %, respectively. The results obtained demonstrated that rapeseed honey enriched with M. albus flowers possesses antiplatelet activity resulting from the synergistic effect of coumarin and other bioactive compounds occurred in dried M. albus flowers, including phe nolic and volatile components.. However, the mechanism of this action needs further study.

Electrochemistry Applied to the Evaluation of the Interaction between Coumarins and the Copper Metal Ion: An Experimental Study with a DFT-Based Analysis

Coumarin belongs to the benzopyrones family commonly found in vegetables such as Guaco. These compounds have a diversity of applications, especially in medicine, because they have vasodilatory, anti-inflammatory, anti-asthmatic, and anti-allergic properties. In addition, metal complexes using coumarins in their structures have been widely studied for therapeutic purposes. Due to the importance of these molecules, in this work, was studied the interaction between coumarin (CM) and 7-hydroxycoumarin (7OHCM), the main metabolite of coumarin, with the metal ion copper (II), which is naturally present in the environment. Cyclic voltammetry studies showed a reduction peak at 0.39 V and an oxidation peak at 0.47 V for the Cu-CM complex under pencil graphite electrode. Cu-7OHCM showed a reduction peak at 0.40 V and an oxidation peak at 0.49 V, both with reversible process characteristics. In the presence of coumarin, Cu+ is stabilized in solution. Theoretical data suggest the formation of the complex and stabilization of Cu+ in solution. After the interaction, a decrease in the energy of the system occurs, as well as an overlap of the HOMO orbitals of the two species was observed. Furthermore, the studies indicated that the Cu-CM complex is more stable than the Cu-7OHCM complex.

Corrosion behavior of MgZnFeCuCo alloys in the presence of coumarin

Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co are produced by using a powder metallurgical process followed by sintering in an argon atmosphere. Potentiodynamic polarization and electrochemical impedance spectroscopy are applied to study the corrosion behavior and corrosion inhibition by coumarin of Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co in Hanks’ solution. Potentiodynamic polarization and electrochemical impedance spectroscopy characterization reveal that Mg-19Zn-17Fe-28Cu-18Co high entropy alloys exhibit better corrosion resistance than Mg-11Zn-26Fe-7Cu-4Co, and Mg-11Zn-6Fe-0.2Cu-0.3Co in Hanks’ solution. The addition of coumarin effectively inhibits corrosion of Mg-11Zn-26Fe-7Cu-4Co, Mg-11Zn-6Fe-0.2Cu-0.3Co, and Mg-19Zn-17Fe-28Cu-18Co high entropy alloys in Hanks’ solution.

Anticoagulant Properties of Medicinal Plants of Asteraceae: A Systematic Review

The Asteraceae family is considered to be the largest family of flowering plants. Asteraceae includes annuals, perennials, ground covers, vines, and shrubs. Plants belonging to this family are used as a conventional medicine all over the world, and it has been shown to have a range of biological benefits, including anti-inflammatory, antioxidant, and anticoagulant properties. Plants from the Asteraceae are believed to be rich in flavonoids, coumarins, and other constituents that help in the coagulation process. This systematic review generally aims to provide an overview concerning the anticoagulant activity of different medicinal plants under the family of Asteraceae. After rigorous screening using combined SPIDER and PICO strategies, 17 experimental studies with Asteraceae plants showing anticoagulant activity were included. The different plants from the family were extracted using water, methanol, ethanol, and hexane method. Anticoagulant activity of different plants from the Asteraceae family was determined by performing tests and monitoring activated partial thromboplastin time and prothrombin time in vitro and in vivo to assess the intrinsic and extrinsic pathway. Moreover, the presence of coumarin, flavonoids, and polysaccharides significantly increased the aPTT and PT. Thus, these results suggest that the chemical constituents of Asteraceae plants may have the potential to prevent or improve thrombosis by inhibiting platelet activation and blood coagulation.

Coumarin Exhibits Broad-Spectrum Antibiofilm and Antiquorum Sensing Activity against Gram-Negative Bacteria: In Vitro and In Silico Investigation.

Quorum sensing (QS) and biofilm inhibition are recognized as the novel drug targets for the broad-spectrum anti-infective strategy to combat the infections caused by drug-resistant bacterial pathogens. Many compounds from medicinal plants have been found to demonstrate anti-infective activity. However, broad-spectrum anti-QS and antibiofilm efficacy and their mode of action are poorly studied. In this study, the efficacy of coumarin was tested against QS-regulated virulent traits of Gram-negative bacteria. Coumarin inhibited the production of violacein pigment in Chromobacterium violaceum 12472 by 64.21%. Similarly, there was 87.25, 70.05, 76.07, 58.64, 48.94, and 81.20% inhibition of pyocyanin, pyoverdin, and proteolytic activity, lasB elastase activity, swimming motility, and rhamnolipid production, respectively, in Pseudomonas aeruginosa PAO1. All tested virulence factors of Serratia marcescens MTCC 97 were also suppressed by more than 50% at the highest sub-minimum inhibitory concentration. Moreover, the biofilms of bacterial pathogens were also inhibited in a dose-dependent manner. Molecular docking and molecular dynamics (MD) simulation gave insights into the possible mode of action. The binding energy obtained by docking studies ranged from −5.7 to −8.1 kcal mol–1. Coumarin was found to be docked in the active site of acylhomoserine lactone (AHL) synthases and regulatory proteins of QS. MD simulations further supported the in vitro studies where coumarin formed a stable complex with the tested proteins. The secondary structure of all proteins showed a negligible change in the presence of coumarin. Computational studies showed that the possible mechanisms of anti-QS activity were the inhibition of AHL synthesis, antagonization of QS-regulatory proteins, and blocking of the receptor proteins. The findings of this study clearly highlight the potency of coumarin against the virulence factors of Gram-negative bacterial pathogens that may be developed as an effective inhibitor of QS and biofilms.

Rapid Characterization of Quorum Sensing Inhibitory Molecules from Garcinia indica Choisy Seed Methanol Extract by GC-MS Analysis

Background: Bacteria communicate by producing small signaling molecules to maintain threshold cell density. Quorum sensing inhibition is an effective and most potent approach for the prevention of cell to cell communication. Methods: In the present study, the methanol extract of Garcinia indica was tested for anti-quorum sensing activity using Chromobacterium violaceum as a biosensor. The extract inhibited violacein production in biosensor strain without affecting the growth of the bacteria and this was corroborated by bioautography assay. Results: The bioactive fraction was analysed by the aid of GC-MS revealed that, the presence of coumarin (7-hydroxy-3-(1,1-dimethylprop-2-enyl) coumarin) and eugenol (1,2-dimethoxy-4-(1-methoxy-1- propenyl) benzene) derivatives as anti-quorum sensing molecules. Conclusion: A detailed investigation is required to study the mechanism of action involved in control of quorum sensing signals and possible applications.

Induction, biochemical trait and phytochemical screening of calluses of Amburana cearensis (Allemão) A.C. Smith

Amburana cearensis is an arboreal legume of the Fabaceae family, with high phytotherapic and medicinal potential due the presence of secondary metabolites. The objective of this study was to evaluate the effect of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-amino-2,5,6- trichloro-2-pyridinecarboxylic acid (picloram) on the in vitro induction of callogenesis of A. cearensis and analyze the biochemical and phytochemical potential of these calluses. For callus induction, leaf and cotyledon segments were used as explants, which were inoculated in woody plant medium (WPM) supplemented with different concentrations of 2,4-D (0, 5, 10, 20, 40 μM) or picloram (0, 5, 10, 20, 40, 80 μM). The callus growth curve was estimated based on fresh weight, measured at 7-day intervals until 28 days after inoculation. The calluses were analyzed by biochemical tests to quantify the reducing sugars and total proteins. Phytochemical screening and high-performance liquid chromatography were performed to establish the phytochemical profile of extracts from calluses. The concentrations of 21.94 μM and 26.46 μM of 2,4-D induced the greatest formation of compact and friable calluses from the leaf and cotyledon segments, respectively. The growth curve had two distinct phases (lag and exponential) for both types of calluses evaluated. The maximum levels of reducing sugars and total proteins in the calluses from leaf and cotyledon segments were obtained on the day of inoculation and after 28 days of cultivation, respectively. The results of the phytochemical analysis identified the presence of coumarin in all the extracts evaluated, this secondary metabolite has high pharmacological potential.

Light-Induced EPR Study of the Effect of Coumarin Trace Additives on Spin Dynamics in the P3DDT/PC61BM Polymer Composite

The paper presents the results of an EPR study of the magnetic, relaxation, and dynamic parameters of spin charge carriers photogenerated by light in photovoltaic polymer composites, based on poly(3-dodecylthiophene) (P3DDT) and 6,6-phenyl-C61-butyric acid methyl ester (PCBM), in the presence of coumarin admixed to the system. It has been shown that the concentration of polarons and fullerene radical anions is characterized by a nonmonotonic dependence on the energy of incident photons with extrema at 1.9 and 2.7 eV. The largest increase in the concentration of mobile charge carriers was observed in composites with a coumarin content of 3 or 6 wt %. A significant slowdown of the carrier recombination process in the composites containing 3–6 wt % coumarin was observed after switching off the light. The temperature dependences of the concentrations of mobile and localized charge carriers for P3DDT/PCBM samples with a coumarin content of 3 wt % showed enhancement of the exchange interaction between charge carriers. The data obtained lead to the conclusion that coumarin affects spin interactions in the polymer composite.

Efficacy of plant extracts of two species of Chenopodiaceae on the germination and seedling growth of Beans (Phaseolus vulgaris).

This study was conducted to examine the allelopathic potential of aqueous extracts (A.E.) of two wild plants Bassia muricata(B. muricata) and Chenopodium mural (Ch. Mural) at Different concentration (1, 5, 10, 15,20, 25% w/v) in addition to 0% (tap water) as control ,on seed germination, seedling growth and chlorophyll ,protein and sugar content of Phaseolus vulgaris .L. (Kidney bean). Gas chromatography mass spectrum (GC.MS) analysis revealed the presence of 33 bioactive compounds for Ch. mural extracts and 31 compounds for B. muricate and this analysis showed the presence of many compounds as fatty acid, aliphatic hydrocarbon, polyphenol and sterols. The obtained results indicated that shoot aqueous extract (S.A.E) of B. muricata and Ch. mural at (1% to 15%); (1% and 5% ) respectively as seed soaking for 24 hours stimulated germination percentage and support all tested morphological and physiological parameter of the Phaseolus vulgaris plants, while the reduction was observed at (20 and 25% w/v) in B. muricata and the completely inhibition of Ch. Mural extract was started from 10% as compared with the untreated control plant. The stimulating effect for both wild plants may be related to the presence of the polyphenolic compounds and steroidal hormones according to the concentration. The phytotoxic activity (completely inhibition) of Ch. mural could be related to the presence of coumarin and its derivatives (3-(3,4-dimethoxyphenyl)-7-methyl-4-phenylcoumarin).

Synthesis and characterization of lead sulfide thin films by coumarin assisted CBD method

Coumarin which is a natural substance found in many plants is an organic chemical compound. In this study, we investigated the effects of coumarin adding during the growth of lead sulfide (PbS) thin films by chemical bath deposition (CBD). It was found that significant improvements were observed in the optical and structural properties of the films coated in the presence of coumarin. X-Ray diffraction, UV–vis spectrophotometry and scanning electron microscopy were used to systematically investigate the effect of coumarin on the characteristic properties of the PbS films. X-ray diffraction measurements have revealed that the increasing of coumarin content caused the decreasing the crystallite size of the films. On the other hand, UV–vis analysis showed that the band gap value of the coated samples increased from 1.80 eV to 2.53 eV by changing additive content from 0 to 4%. Also, UV–vis spectra exhibited that the transmittance of the samples varied between 37 and 50%. Further, surface roughness measurements showed that film morphology was influenced by the coumarin content. The results show that coumarin assisted growth of PbS nanostructures is a promising way to improve its physical properties.

ANALGESIC AND ANTI-INFLAMMATORY ACTIVITY OF VARIOUS EXTRACTS OF CLAUSENA DENTATA (WILLD.) ROEM

Objectives: The present study was undertaken to study the analgesic and anti-inflammatory activity of various extracts of Clausena dentata. Clausena (Rutaceae) is a genus of about 23 species of unarmed trees and shrubs. The stem bark of C. dentata is used in veterinary medicine for the treatment of wounds and sprains. Even though C. dentata has a lot of potential medical uses, the study of pharmacological properties is very scarce.Methods: The plant C. dentata was collected in May 1999 from Kadagaman, near Tiruvannamalai, Tamil Nadu, India, and authenticated by Centre for Advanced Study in Botany, University of Madras, Chennai. The dry powder of stem bark was extracted with hexane, chloroform, and methanol. The extracts were subjected to thin-layer chromatography and phytochemical screening. Further, the extracts were tested for analgesic by the tail flick and anti-inflammatory by carrageenan-induced rat paw edema using plethysmometer.Results: Qualitative chemical tests revealed the presence of various phytochemicals such as alkaloids, glycosides, carbohydrate, proteins and amino acids, phytosterols, and volatile oil. The hexane, chloroform, and methanol extracts exhibited significant analgesic activity as compared to control group (Tween 80, 1%). The anti-inflammatory activity of C. dentata extracts revealed that the percent inhibition of carrageenan-induced rat hind paw edema was highly significant as compared to control group after 4 h of injection.Conclusion: The presence of coumarin and alkaloids all the extracts promising properties of analgesic and anti-inflammatory.

Quantification of coumarin and related phenolics in cinnamon samples from south India using UHPLC-ESI-QqQLIT-MS/MS method

ABSTRACTThe presence of coumarin, a hepatotoxic phenyl propanoid, in samples of the spice, cinnamon, procured from the market has raised food safety concerns world over. A validated, ultra-performance liquid chromatography- linear ion trap triple quadrupole mass spectrometry method was developed in the present study for the estimation of coumarin and other phenolics in authentic Cinnamomum verum bark samples and market samples from south India. Coumarin contents in authentic bark samples were in the range of 12.3 to 143.0 mg/kg, whereas the coumarin contents in samples procured from the market were up to 3462.0 mg/kg. The high content of coumarin and cinnamaldehyde in cinnamon samples procured from the market suggested possible blending with substitutes like Cinnamomum cassia barks, which possess substantial amounts of coumarin and cinnamaldehyde.

Design of Nickel Electrodes by Electrodeposition: Effect of Internal Stress on Hydrogen Evolution Reaction in Alkaline Solutions

Here we report the fabrication of Ni electrodes with induced internal stress, electrodeposited in the presence of coumarin (COU) or 1,3,6-naphthalenetrisulfonic acid trisodium salt (NTS), to enhance the hydrogen evolution reaction. The crystallographic structure and morphology of the Ni electrodeposits prepared from a plating bath containing COU showed large columnar structures with a [100] preferred orientation, whereas the electrodeposits with NTS grew fine columnar structures along the [111] and [100] direction. The tensile or compressive stress in the Ni lattice was controlled by additive concentration, which led to the incorporation of hydrogen or sulfur in the Ni matrix. The Ni electrode with induced compressive stress exhibited a higher exchange current density and lower Tafel slopes than those with induced tensile stress, which can be attributed to modification of the hydrogen adsorption energy, as evidenced by a downshift in the d-band center.

Influence of tetrabutylammonium cations on phase transition within adsorbed adlayer and lifting of reconstruction at Au(111) electrode in sulfate solution and in presence of coumarin

The effect of tetrabutylammonium (TBA) cations on phase transition within adsorbed adlayer and lifting of reconstruction at Au(111) electrode in sulfate solution and in presence of coumarin (CUM) has been studied by means of the cyclic voltammetry and differential capacity measurements. TBA cations retard the adsorption of sulfate anions which is responsible for the lifting of the reconstruction. Next, the presence of TBA cations in sulfate solution induces the appearance of phase transition in CUM adlayer for twice lower coumarin concentration and at much more negative potentials. Moreover, the protection against the sulfate anions adsorption which lifts the reconstruction is higher for CUM molecules than for TBA cations.

Optopharmacological control of TRPC channels by coumarin-caged lipids is associated with a phototoxic membrane effect.

Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling pathways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca(2+) homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC signaling at the level of membrane conductance and cellular Ca(2+) handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light (340 nm) as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 μmol L(-1) concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca(2+) responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using coumarin-caged second messengers in cellular studies.

Phytochemical Profile of Seed Extracts of Plants Typical of the Brazilian Semiarid and their Potential Application in Brackish Water Desalination

The phytochemical profile of typical seeds from semiarid areas of Bahia was explored. The desalination capacity of the seeds discovered in previous studies considered the seeds potentially suitable for desalination of water. Coals composed of crushed seeds of umbu (Spondias tuberosa Arr. Cam.) and umburana (Amburana cearensis A. C. Sm.) were prepared by heating at 250 oC. As the desalination process using these materials involves ion exchange besides adsorption, it became necessary to study their chemical composition to check the possibility of transferring undesirable chemical species to the water during the contact between material and water. None of the tested metabolites were found in umbu coal, which enabled its use in desalination. However, the presence of coumarin and alkaloids in the umburana seeds coal indicated that this material is not suitable for that use.

Prospects of Cinnamon in Multiple Sclerosis.

Although the central nervous system (CNS) is separated from the immune system by blood-brain barrier and traditionally considered “immune priviledged”, our immune cells are capable of targeting the brain, leading to the development of CNS autoimmune disorders. Multiple sclerosis (MS) is one such autoimmune disorder of the CNS in which myelin components are particularly targeted by the immune system resulting in demyelination of axons and associated debilitating symptoms [1–3]. In spite of intense investigations, no effective therapy is available for this disease. Therefore, a safe and effective therapeutic option is necessary for MS. Fortunately, we have been endowed with enormous natural remedies to take care our health issues. For example, cinnamon, the brown bark of cinnamon tree, that has already been being used for centuries throughout the world as spice or flavoring agent. Furthermore, medieval physicians used cinnamon for medical purposes to treat a variety of disorders including arthritis, coughing, hoarseness, sore throats, etc. Recent studies are indicating that this natural product may be helpful for MS [4–6]. Although the etiology of MS is poorly understood, it is becoming clear that widespread inflammation, loss of regulatory T cells (Tregs), hyperactivity of autoimmune Th1 and Th17 cells, breakdown of blood-brain barrier (BBB) and blood-spinal cord barrier (BSB), and loss of neuroprotective molecules in the CNS are critical for the manifestation of demyelinating pathology in MS [1–3]. Interestingly, cinnamon treatment is capable of modifying these pathological features in mice with experimental allergic encephalomyelitis (EAE), an animal model of MS [4,6]. Types of cinnamon Cinnamonum cassia (Chinese cinnamon) and Cinnamonum verum or Cinnamonum zylencum (Ceylon cinnamon) are two readily available brands of cinnamon in the world. Although both types of cinnamon contain cinnamaldehyde as the major compound, we have seen the presence of coumarin, a hepatotoxic molecule, in Cinnamonum cassia, but not Cinnamonum verum. Furthermore, Cinnamonum cassia contain more styrene, benzene, 1,1′-(2-butene-1,4-diyl)bis-, benzene, 1,1′-(1,2-cyclobutanediyl)bis-, palmitic acid, stearic acid, 4-phenylbutyl chloride, and (2,3-diphenylcyclopropyl) methyl phenyl sulfoxide, which are present in Cinnamonum verum in negligible amounts [7]. Therefore, for the treatment of mice with EAE, we used Cinnamonum verum. Upon ingestion, cinnamaldehyde present in Cinnamon is converted into cinnamic acid by oxidation. In the liver, this cinnamic acid is β-oxidized to benzoate that exists as sodium benzoate (NaB) or benzoyl-CoA. A minor amount of NaB, a direct metabolite of cinnamic acid, is also excreted in the urine of humans. Recently, we have demonstrated that oral administration of ground Cinnamonum verum increases the level of NaB in serum and brain of mice [7]. NaB is of medical importance as being a component of Ucephan, a FDA-approved drug, it is used in the treatment for hepatic metabolic defects associated with hyperammonemia such as urea cycle disorder in children [8,9]. NaB is also a widely used preservative in broad range of foods and cosmetic products. It has been reported that 2% solution of NaB in drinking water is safe for lifelong treatment in mice without any noticeable side effects [10].

Mikania glomerata Sprengel (Asteraceae) Influences the Mutagenicity Induced by Doxorubicin without Altering Liver Lipid Peroxidation or Antioxidant Levels

As shown in numerous studies, natural compounds may exert adverse effects, mainly when associated with some drugs. The hydroalcoholic extract of Mikania glomerata is the pharmaceutical form present in commercially available syrup used for the treatment of respiratory diseases in popular Brazilian medicine. The objective of the present investigation was (1) to evaluate the preventive effects of standardized hydroalcoholic extract of M. glomerata (MEx) against antitumoral drug doxorubicin (DXR)-induced micronucleated polychromatic erythrocytes (MNPCE) in a subchronic assay in mice, and (2) to determine the liver content of malondialdehyde (MDA) and the antioxidants glutathione (GSH) and vitamin E (VE). Male Swiss mice were treated for 30 d with MEx added to drinking water, combined or not with DXR (90 mg/kg body weight) injected intraperitoneally (ip) 24 h before analysis. The results demonstrated that MEx produced no genotoxic damage, but significantly increased the frequency of MNPCE induced by DXR, indicating a drug–drug interaction. This rise was not accompanied by lipid peroxidation or antioxidants level reduction, as measured by MDA, GSH, and VE. Despite the presence of coumarin (a known antioxidant), MEx may exert adverse effects probably in association with mutagenic compounds, although this effect on DNA damage did not involve oxidative stress.

Development and single-laboratory validation of an HPLC method for the determination of in foodstuffs using internal standardization and solid-phase extraction cleanup.

A selective, sensitive and rapid procedure based on liquid chromatography with photodiode array detection (HPLC-PDA) has been developed, single laboratory validated and cross-validated by an external laboratory for the determination of coumarin, a naturally occurring biologically active principle, in a range of foods and beverages. Reverse phase solid-phase extraction (SPE) was used to clean sample extracts when co-extractives were found to interfere with detection and the presence of coumarin was confirmed by comparison of chromatographic peak UV spectra with coumarin standards and quantified by the use of an internal standard. The method was applied to the analysis of flour products, breakfast cereal, gelatin confectionery, sugar confectionery, rice pudding, mixed spice, camomile infusion and soft drinks. Coumarin could not be confirmed in extracts of camomile infusions due to the presence of co-eluting peaks as confirmed by UV spectral analysis. Chromatographic separation was achieved on an octadecyl (C8) column using a mobile phase gradient of acetonitrile and 0.5% acetic acid with a total run time of 20 minutes. The limits of detection and quantification were sample dependent and ranged from 0.05 to 2.5 mg kg-1 and 0.05 to 8 mg kg-1 respectively. The method was successfully validated to show the standard range linearity, sensitivity, accuracy and precision in the matrices tested. Coumarin is regulated within the European Union so this method may be readily adapted for enforcement purposes.