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Phytochemical Analysis - Current Research Articles

Current research articles: Phytochemistry

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Phytochemical Analysis - published by Wiley

Phytochemical Analysis devoted to the publication of original articles concerning the development, improvement, validation and/or extension of application of analytical methodology in the plant sciences. The spectrum of coverage is broad, encompassing methods and techniques relevant to the detection (including bio-screening), extraction, separation, purification, identification and quantification of compounds in plant biochemistry, plant cellular and molecular biology, plant biotechnology, the food sciences, agriculture and horticulture

Current articles of the journal:

Arylnaphthalene and Aryltetralin-type Lignans in Hairy Root Cultures of Linum perenne, and the Stereochemistry of 6-Methoxypodophyllotoxin and One Diastereoisomer by HPLC-MS and NMR Spectroscopy

Introduction Hairy root cultures of Linum sp. are an alternative for the high production of lignans. Linum perenne is known to produce arylnaphthalene-type lignans such as justicidin B, isojusticidin and diphyllin. Objective To elucidate the presence of aryltetralin-type lignan diastereoisomers, besides the known arylnaphthalene-type lignans, in hairy roots of Linum perenne, and to determine the configurations of one diastereoisomer of 6-methoxypodophyllotoxin (6-MPTOX). Methods Lignans from hairy root cultures of Linum perenne were extracted and separated by HPLC. Arylnaphthalene-type lignans were identified by LC-MS, according to the literature. Two diastereoisomers of aryltetralin-type lignans were analysed by mass spectrometry and NMR spectroscopy. Results Numerous arylnaphthalene-type lignans (diphyllin-2-hexose-pentose, diphyllin-3-pentose and diphyllin-hexose) were identified in hairy root cultures. Methoxypodophyllotoxin, an aryltetralin-type lignan, was also identified, as well as one diastereoisomer. This aryltetralin-type lignan could be derived via 7-hydroxymatairesinol as a hypothetical biosynthetic pathway. The stereochemical configurations of aryltetralin isomers were determined. Conclusion Arylnaphthalene and two diastereoisomers of aryltetralin-type lignans are produced in Linum perenne hairy root cultures. Matairesinol, the precursor of justicidin B, also seems to be converted into 6-MPTOX via 7-hydroxymatairesinol. This is the first report of the stereochemical configurations of an aryltetralin-type lignan other than podophyllotoxin (PTOX). Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 15 May 2015 | 4:05 pm

LC-MS-based Metabolite Profiling of Methanolic Extracts from the Medicinal and Aromatic Species Mentha pulegium and Origanum majorana

Introduction There has been increasing interest dedicated to the phenolic compounds with a view to their antioxidant and healthy properties. Recent studies have focused on plants from the Lamiaceae family with special interest in phenolic compounds antioxidant potential. Objective The metabolite profile of methanolic extracts from two Lamiacea medicinal plants was investigated. Materials and Methods Mentha pulegium and Origanum majorana methanolic extracts were analysed using reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) coupled to electrospray ionisation quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS) detection in the negative ion mode. Results A total of 85 metabolites were characterised from different families, such as organic acids and derivatives, amino acids and derivatives, nucleosides, phenolic compounds as well as other polar metabolites, by using the MS and MS/MS information provided by the QTOF-MS. However, the total phenols and flavonoids were also quantified spectrophotometrically and they registered higher amounts in Mentha pulegium than in Origanum majorana extract. Gallocatechin was the major compound in M. pulegium extract whereas quercetin dimethyl ether, jaceidin and dihydrokaempferide were the major ones in O. majorana extract. Conclusion The distribution of phenolic compounds in the methanolic extract showed a variation among studied plants. Mentha pulegium can be considered as a source of gallocatechin. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 15 May 2015 | 4:04 pm

The Minor Ecdysteroids from Ajuga turkestanica

Introduction Ajuga turkestanica is a plant used in traditional medicine for its high ecdysteroid content, including the presence of the particularly active turkesterone, which possess efficient anabolic activity. Objectives To isolate and identify minor ecdysteroids present in a semi-purified plant fraction containing ca. 70% turkesterone. Material and Methods Multi-step preparative HPLC (combining RP- and NP-HPLC systems) was used to purify the different components present in the turkesterone fraction. Isolated compounds were identified by high-resolution mass spectrometry and 2D-NMR. Results Fourteen ecdysteroids (including turkesterone and 20-hydroxyecdysone) were isolated. Seven of these, all bearing an 11?-hydroxy group, were previously unreported. Conclusion Ajuga turkestanica ecdysteroids are characterised by the abundance of 11?-hydroxylated compounds and by the simultaneous presence of 24C, 27C, 28C and 29C ecdysteroids. It is expected that even more ecdysteroids are to be found in this plant since the starting material for this study lacked the less polar ecdysteroids. The simultaneous presence of 20-hydroxyecdysone and turkesterone (its 11?-hydroxy analogue) as the two major ecdysteroids suggests that every ecdysteroid is probably present in both 11?-hydroxy and 11-deoxy forms. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 8 May 2015 | 9:48 am

Efficient Combination of Circulating Ultrasound-assisted Extraction and Centrifugal Partition Chromatography for Extraction and On-line Separation of Chemical Constituents from Stellera chamaejasme L.

Introduction Sample preparation is a crucial step in medicinal herb analysis because the desired chemical components need to be extracted from the herbal materials for further separation and characterisation. Thus, the development of " modern" sample preparation techniques with significant advantages over conventional methods is very important. Objective The aim of this study was the development of a new preparation method using circulating ultrasonic-assisted extraction (CUAE) coupled with centrifugal partition chromatography (CPC) for continuous extraction and on-line isolation of chemical constituents from Stellera chamaejasme L. Methodology The stationary or mobile phase was used as the extraction solvent. Extraction parameters, including the ultrasound power, extraction time, temperature, and liquid:solid ratio, were optimised using a response surface methodology. Results The extraction time, temperature, and power considerably affected the extraction yield. The optimised extraction parameters were an ultrasound power of 800?W, extraction time of 30?min, extraction temperature of 70?°C, and liquid:solid ratio of 8?mL/g. The solvent system for CUAE and CPC was optimised using mathematical equations, and the two-phase solvent system of n-hexane:ethyl acetate:methanol:water at a volume ratio of 3:5:4:6 was calculated. Four target compounds (daphnoretin, chamaechromone, neochamaejasmin A, and isochamaejasmin) with purities above 96% were successfully extracted and isolated on-line via CUAE/CPC. Conclusion Compared with the reference extraction methods, the instrumental setup achieved a scientific and systematic extraction and isolation of natural products and has great potential for industrial application. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 22 April 2015 | 9:22 am

Multiresponse Optimisation Applied to the Development of a TLC Autography for the Detection of Tyrosinase Inhibitors

Introduction Autographic methods are useful tools to detect bioactive compounds in complex matrixes. Experimental design and optimisation techniques were implemented for the development of an autographic assay suitable for the detection of tyrosinase inhibitors. Objectives To develop an autographic assay to detect tyrosinase inhibitors using gel entrapped enzyme, experimental design and response surface methodology (RSM) to optimise conditions with a minimum number of experiments. Methods Gel entrapment was used for the assay and the effects of four factors on the sensitivity and the detection limit for known inhibitors of the enzyme were evaluated. The factors were: tyrosinase amount (TA), L-tyrosine amount (LTA), incubation time and incubation temperature. Results The assay allowed the detection of kojic acid in an extract of Calamagrostis viridiflavescens (Poir.) Steud spiked with 0.1% w/w. Conclusion The developed assay is able to detect tyrosinase inhibitors present in complex matrixes in a reproducible way. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 25 March 2015 | 6:19 am

Rapid Identification of Steroidal Saponins in Trillium Tschonoskii Maxim by Ultraperformance Liquid Chromatography Coupled to Electrospray Ionisation Quadrupole Time-of-Flight Tandem Mass Spectrometry

Introduction Steroidal saponins in Trillium tschonoskii Maxim have many biological activities, including immunological regulation and anti-tumour. Comprehensive ingredient identification is critical for understanding its pharmacological mechanism and establishing quality control protocols. However, it is a challenging problem because of the complexity of steroidal saponins. Objectives To develop a UPLC–MS method for identifying and characterising steroidal saponins in the root and rhizome of T. tschonoskii. Methods Methanolic extracts of T. tschonoskii were analysed by using ultraperformance liquid chromatography coupled to electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC–ESI/QTOF/MS). The UPLC experiments were performed by means of a reversed-phase C18-column and a binary mobile phase system consisting of water and acetonitrile with formic acid under gradient elution conditions. For the UPLC–MS measurements, positive and negative ion modes were used in order to obtain better tandem mass spectra and high-resolution mass spectra. Results Based on retention times, accurate mass and mass spectrometric fragmentation, a total of 31 saponins distributed over eight steroidal aglycone skeletons were identified or tentatively elucidated from T. tschonoskii. Conclusion The UPLC–ESI/QTOF/MS method has proven to be a powerful tool for rapid identification of steroidal saponins in T. tschonoskii without tedious and time-consuming isolation of pure constituents. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 21 March 2015 | 3:04 pm

Comprehensive Two-dimensional Gas Chromatography Time-of-flight Mass Spectrometry to Assess the Presence of ?,?-Trehalose and Other Disaccharides in Apple and Peach

Introduction Carbohydrates are important constituents in fruits. Among the carbohydrates, disaccharides have rarely been studied in apple and peach. Indeed, the abiotic stress biomarker and preservation agent ?,?-trehalose is a disaccharide. Objectives To establish a comprehensive method based on two-dimensional gas chromatography combined with time-of-flight MS detection (GC?×?GC–ToF/MS) to analyse the disaccharide composition of apple and peach. Methods The sample preparation was based on aqueous-methanolic extraction of the analytes, followed by oxime formation and trimethylsilylation of the disaccharides. First, three columns were tested with standards on the one-dimensional system. Next, to perform the sample analysis using GC?×?GC–MS (which offers significant advantages over conventional GC because it allows higher separation efficiencies), various column configurations were assessed on the two-dimensional system to obtain enhanced separation and low detection limits. The column sets tested included non-polar/semi-polar, semi-polar/polar and polar/non-polar. Results Using the method that proved to be more efficient, namely the method developed with the semi-polar/non-polar configuration, ten disaccharides were identified, based on analytical standards, retention index and mass spectra. These compounds were quantified in several varieties of apple and peach fruit using the developed GC?×?GC method and linear curve calibration, resulting in substantial differences among the fruits. However, cultivars within the fruits exhibited no significant differences. Conclusion The proposed method allowed for the identification and quantification of several disaccharides in apple and peach, including the biomarker ?,?-trehalose. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 19 March 2015 | 8:56 am

Investigation of the Role of the Calvin Cycle and C1 Metabolism during HCHO Metabolism in Gaseous HCHO-Treated Petunia under Light and Dark Conditions Using 13C-NMR

Introduction It has been shown that formaldehyde (HCHO) absorbed by plants can be assimilated through the Calvin cycle or C1 metabolism. Our previous study indicated that Petunia hybrida could effectively eliminate HCHO from HCHO-polluted air. Objective To understand the roles of C1 metabolism and the Calvin cycle during HCHO metabolism and detoxification in petunia plants treated with gaseous H13CHO under light and dark conditions. Methods Aseptically grown petunia plants were treated with gaseous H13CHO under dark and light conditions. The metabolites generated from HCHO detoxification in petunia were investigated using 13C-NMR. Results [2-13C]glycine (Gly) was generated via C1 metabolism and [U-13C]glucose (Gluc) was produced through the Calvin cycle simultaneously in petunia treated with low-level gaseous H13CHO under light conditions. Generation of [2-13C]Gly decreased whereas [U-13C]Gluc and [U-13C]fructose (Fruc) production increased greatly under high-level gaseous H13CHO stress in the light. In contrast, [U-13C]Gluc and [U-13C] Fruc production decreased greatly and [2-13C]Gly generation increased significantly under low-level and high-level gaseous H13CHO stress in the dark. Conclusion C1 metabolism and the Calvin cycle contributed differently to HCHO metabolism and detoxification in gaseous H13CHO-treated petunia plants. As the level of gaseous HCHO increased, the role of C1 metabolism decreased and the role of the Calvin cycle increased under light conditions. However, opposite changes were observed in petunia plants under dark conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 19 February 2015 | 6:56 am

Quantitative Determination of Secoiridoids and Phenylpropanoids in Different Extracts of Ligustrum Vulgare L. Leaves by a Validated HPTLC–Photodensitometry Method

Introduction The genus Ligustrum (Oleaceae) is distributed in Europe and Asia (south China and Korea), where it is used to prevent hypertension, sore throats, inflammation and diabetes. The main groups of compounds in extracts of Ligustrum vulgare are biologically active secoiridoids and phenylpropanoids. Objectives The aim of the study was primarily the development and validation of a HPTLC–photodensitometry method for separation and determination of secoiridoids (oleacein, oleuropein) and phenylpropanoids (echinacoside) in different extracts prepared from leaves of L. vulgare. A secondary issue was the quantitative screening of oleacein, oleuropein and echinacoside in extracts from leaves collected at different stages of plant growth (from May to September). Methods A HPTLC–photodensitometry method was developed and validated for quantification of oleuropein, oleacein and echinacoside in plant extracts (aqueous and ethanolic extract, decoction, infusion). Silica gel was used as the stationary phase and dichloromethane:methanol:formic acid:water (80:25:1.5:4, v/v/v/v) as the mobile phase. Results The HPTLC–photodensitometry method developed for quantification of oleacein, oleuropein and echinacoside was specific, accurate and precise. The presence of oleacein was detected in aqueous extracts, whereas oleuropein was present, in particular, in ethanolic extracts, decoctions and infusions. Echinacoside was detected in all the extracts prepared. The content of secoiridoids was variable from May to September, whereas the amount of echinacoside increased in this term. Conclusion The developed and validated HPTLC–photodensitometry method allowed performing fast screening of quantitative profiles of oleacein, oleuropein and echinacoside in preparations of privet leaves. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 19 February 2015 | 6:56 am

Discriminating Lamiophlomis rotata According to Geographical Origin by 1H-NMR Spectroscopy and Multivariate Analysis

Introduction Lamiophlomis rotata (Duyiwei) is a folk herbal medicine that traditionally has been used in China as a hemostatic agent. Raw plant materials used for medicinal products from different geographical regions are often inconsistent in chemical composition. Metabolic fingerprinting provides a new approach for distinguishing the geographical origins of L. rotata. Objective To identify metabolites that contribute to the different geographical regions of L. rotata samples. Methods Lamiophlomis rotata metabolomics were performed by 1H-nuclear magnetic resonance (NMR) spectroscopy and multivariate statistical analyses. The L. rotata metabolic profile was prepared for NMR measurements using methanol-d4 solvent. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to analyse the L. rotata 1H-NMR spectroscopy data. Results Nine iridoid glycosides, one flavonoid and three phenylpropanoid glycosides were detected in L. rotata by 1H-NMR spectroscopy. 1H-NMR measurements and multivariate analysis were used to successfully discriminate samples from three different locations. Conclusion The NMR-based analysis of L. rotata is a more comprehensive approach than traditional chromatographic methods. Simple sample preparation, rapidity and reproducibility of are additional advantages of NMR analysis. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 19 February 2015 | 6:55 am

Root Cause Analysis of Quality Defects Using HPLC–MS Fingerprint Knowledgebase for Batch-to-batch Quality Control of Herbal Drugs

Introduction The batch-to-batch quality consistency of herbal drugs has always been an important issue. Objectives To propose a methodology for batch-to-batch quality control based on HPLC–MS fingerprints and process knowledgebase. Methods The extraction process of Compound E-jiao Oral Liquid was taken as a case study. After establishing the HPLC–MS fingerprint analysis method, the fingerprints of the extract solutions produced under normal and abnormal operation conditions were obtained. Multivariate statistical models were built for fault detection and a discriminant analysis model was built using the probabilistic discriminant partial-least-squares method for fault diagnosis. Results Based on multivariate statistical analysis, process knowledge was acquired and the cause–effect relationship between process deviations and quality defects was revealed. The quality defects were detected successfully by multivariate statistical control charts and the type of process deviations were diagnosed correctly by discriminant analysis. Conclusion This work has demonstrated the benefits of combining HPLC–MS fingerprints, process knowledge and multivariate analysis for the quality control of herbal drugs. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 19 February 2015 | 6:55 am

Densitometric Validation and Optimisation of Polyphenols in Ocimum sanctum Linn by High Performance Thin-layer Chromatography

Introduction Ocimum sanctum Linn (Sanskrit: Tulasi; family: Libiaceae), popularly known as holy basil or Ocimum teinufolium, is found throughout the semitropical and tropical parts of India. In Ayurveda, Tulasi has been well known for its therapeutic potentials. Objective To optimise and develop a standard method to quantify seven polyphenols simultaneously by HPTLC. Methods A three-level factor Box–Behnken statistical design was used for optimisation, where extraction time (min), temperature (°C) and methanol:water ratio (% v/v) are the independent variables with polyphenols as the dependent variable. The separation was archived on a silica-gel 60?F254 HPTLC plate using toluene:ethyl acetate:formic acid:methanol (3:3:0.8:0.2?v/v) as the mobile phase. Densitometric analysis of polyphenols was carried out in the absorbance mode at 366?nm. Results The quantification of polyphenols was carried out based on peak area with a linear calibration curve at concentration ranges of 60–240, 20–200, 100–1600, 40–200, 200–1400, 10–160, 200–1400, 100–5000?ng/band for caffeic acid, ellagic acid, rutin, kaempferol, catechin, quercetin, eupalitin and epicatechin respectively. The method was validated for peak purity, precision, accuracy, limit of detection (LOD) and quantification (LOQ). Method specificity was confirmed using the retention factor value and visible spectra correlation of marker compounds. Conclusions A validated HPTLC method was newly developed for simultaneous quantification of seven polyphenols in an Ayurvedic preparation of O. sanctum. The proposed method is simple, precise, specific, accurate, cost-effective, less time consuming and has the ability to separate the polyphenols from other constituents. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 10 February 2015 | 7:17 am

Recognition of Pyrrolizidine Alkaloid Esters in the Invasive Aquatic Plant Gymnocoronis spilanthoides (Asteraceae)

Introduction The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloids in the plant. Objective To determine whether the attraction of the butterflies to the plant is an accurate indicator of pyrrolizidine alkaloids in G. spilanthoides. Methods The alkaloid fraction of a methanolic extract of G. spilanthoides was analysed using HPLC with electrospray ionisation MS and MS/MS. Two HPLC approaches were used, that is, a C18 reversed-phase column with an acidic mobile phase, and a porous graphitic carbon column with a basic mobile phase. Results Pyrrolizidine alkaloids were confirmed, with the free base forms more prevalent than the N-oxides. The major alkaloids detected were lycopsamine and intermedine. The porous graphitic carbon HPLC column, with basic mobile phase conditions, resulted in better resolution of more pyrrolizidine alkaloids including rinderine, the heliotridine-based epimer of intermedine. Based on the MS/MS and high-resolution MS data, gymnocoronine was tentatively identified as an unusual C9 retronecine ester with 2,3-dihydroxy-2-propenylbutanoic acid. Among several minor-abundance monoester pyrrolizidines recognised, spilanthine was tentatively identified as an ester of isoretronecanol with the unusual 2-acetoxymethylbutanoic acid. Conclusions The butterflies proved to be reliable indicators for the presence of pro-toxic 1,2-dehydropyrrolizidine alkaloids in G. spilanthoides, the first aquatic plant shown to produce these alkaloids. The presence of the anti-herbivory alkaloids may contribute to the plant's invasive capabilities and would certainly be a consideration in any risk assessment of deliberate utilisation of the plant. The prolific growth of the plant and the structural diversity of its pyrrolizidine alkaloids may make it ideal for investigating biosynthetic pathways or for large-scale production of specific alkaloids. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 27 January 2015 | 9:47 am

Systematic Separation and Purification of Iridoid Glycosides and Crocetin Derivatives from Gardenia jasminoides Ellis by High-speed Counter-current Chromatography

Introduction Iridoid glycosides and crocetin derivatives are the main bioactive components of Gardenia. The processes of separation of these compounds reported in much of the literature are tedious, time consuming and require multiple chromatographic steps, which results in lower recovery and higher costs. Objective To develop a high-speed counter-current chromatography (HSCCC) method for the systematic separation and purification of iridoid glycosides and crocetin derivatives on a preparative scale from Gardenia. Methods After fractionation using HPD100 column chromatography, n-butanol:ethanol:water (10:1:10, v/v) was selected to purify gardenoside, 6?-hydroxy geniposide and geniposidic acid from fraction A; ethyl acetate:n-butanol:water (2:1.5:3, v/v) was used to isolate geniposide from fraction B; crocin-1, crocin-2, crocin-3 and crocin-4 were purified by hexane:ethyl acetate:n-butanol:water (1:2:1:5, v/v) from fraction C. The head-to-tail elution mode was used with a flow rate of 8.0?mL/min and a rotary speed of 600?rpm. Results After HSCCC isolation, 151.1?mg of gardenoside, 52.2?mg of 6?-hydroxy geniposide and 24.5?mg of geniposidic acid were obtained from 800?mg of fraction A; 587.2?mg of geniposide was obtained from 800?mg of Fraction B; 246.2?mg of crocin-1, 34.2?mg of crocin-2, 24.4?mg of crocin-3 and 24.7?mg of crocin-4 were obtained from 1000?mg of fraction C. Their purities were found by UPLC analysis to be 91.7%, 93.4%, 92.5%, 98.2%, 94.1%, 96.3%, 94.1% and 98.9% respectively. Conclusion The present results demonstrates that the main iridoid glycosides and crocetin derivatives in Gardenia can be obtained efficiently from extracts using HSCCC. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 27 January 2015 | 9:19 am

Non-targeted Molecular Characterisation of a Rose Flower Ethyl Acetate Extract Using Ultra-HPLC with Atmospheric Pressure Photoionisation and Quadrupole Time-of-flight MS/MS

Introduction A non-targeted approach to characterise the phytochemical composition of the flower organ of an original rose cultivar ‘Jardin de Granville’® was developed. Particular attention was paid to the less documented molecular families of intermediate polarity, compared with the polyphenol family (anthocyanins, flavonoids, tannins) and volatile compounds. Objective To develop a molecular fingerprinting method for the rapid qualitative phytochemical characterisation of the rose flower ethyl acetate extract. Material and methods An ultra-HPLC with atmospheric pressure photoionisation (APPI) and quadrupole time-of-flight (QTOF) MS/MS combined with microwave-assisted extraction was carried out for ethyl acetate extracts as an intermediate polarity extraction solvent in order to obtain the most exhaustive extract containing a large range of molecular families. An optimised methodology based on the coupling of the UHPLC and APPI source with a QTOF analyser was developed to characterise the extracted molecules. Results Sixty-one compounds were identified in the extract, covering eight molecular families of intermediate polarity ranging from polyphenols to triglycerides. The presence of flavonoids with anti-oxidant properties and of triterpenoids with potential anti-inflammatory activity was evidenced and cell-wall constituents such as fatty acids, glycolipids, sphingolipids and acylated sterol glycosides were characterised. Some chlorophyll derivatives were also detected. Conclusion The method developed is appropriate for fast phytochemical evaluation of rose ethyl acetate extract. It produced accurate mass and MS/MS spectra, which permitted identification of a wide range of compounds of intermediate polarity. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 27 January 2015 | 8:43 am

LC–MS/MS Quantitative Determination of Tetrapterys mucronata Alkaloids, a Plant Occasionally used in Ayahuasca Preparation

Introduction Tetrapterys mucronata Cav. (Malpighiaceae) is a plant used in some regions of Brazil in the preparation of ayahuasca. Objective To determine the content of the main tryptamine alkaloids in the stem bark of T. mucronata Cav. and assess their possible toxic and hallucinogenic properties based on the doses found in a water decoction that mimics the ayahuasca preparation. Methods Four alkaloids previously described for their toxic and hallucinogenic properties were quantitated by multiple reaction monitoring HPLC combined with electrospray ionisation and tandem MS (HPLC–ESI/MS/MS) in the water decoction and ethanolic extracts from the bark of T. mucronata. Results Exhaustive extraction of the stem barks with ethanol revealed the following alkaloid levels: bufotenine (1) 3.26?±?0.31?mg/g, 5-methoxy-N-methyltryptamine (2) 0.88?±?0.08?mg/g, 5-methoxy-bufotenine (3) 3.07?±?0.22?mg/g and 2-methyl-6-methoxy-1,2,3,4-tetrahydro-?-carboline (4) 0.14?±?0.004?mg/g. The water decoction presented slightly lower levels, ranging between 2.32?±?0.14, 0.50?±?0.04, 1.53?±?0.09 and 0.10?±?0.01?mg/g for (1), (2), (3) and (4) respectively. Conclusions The HPLC–ESI/MS/MS quantitation revealed significant alkaloid levels, in particular for bufotenine and 5-methoxy-bufotenine. As such compounds are known for their toxic and hallucinogenic properties, these results indicate that the consumption of this plant as an ingredient in ayahuasca preparations may present a risk to consumers. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 26 January 2015 | 6:22 am

Trace Determination of Lead, Chromium and Cadmium in Herbal Medicines Using Ultrasound-Assisted Emulsification Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry

Introduction The World Health Organization (WHO) recommends that medicinal plants should be checked for the presence of heavy metals. A preconcentration and separation technique for trace amounts of heavy metals from plant matrix is necessary in order to increase the sensitivity and precision of their determination. Objective Lead, chromium and cadmium contaminations in herbal medicines were monitored using ultrasound-assisted emulsification microextraction (USAEME) combined with graphite furnace atomic absorption spectrometry (GF–AAS). Methods In this work, the metal ions in the aqueous solution were complexed with ammonium pyrrolidine dithiocarbamate (APDC) and were extracted into 45??L of toluene that was sonically dispersed in the aqueous phase. The emulsion formed was centrifuged and 20??L of separated toluene was injected into a GF–AAS for analysis. Several factors including the kind of extraction solvent and its volume, sample pH, ionic strength and concentration of APDC were optimised. Results The linear dynamic range (LDR) values were in the range of 0.05 to 20?µg/L and the limit of detection values were in the range of 0.002–0.03?µg/L for target heavy metals. Enrichment factors were obtained in the range of 70–500. The precision of the proposed method was ?8% (n?=?5). The obtained amounts of Pb, Cr and Cd in selected herbal medicines were in the standard range, according to the WHO reports. Conclusion The USAEME with GF–AAS procedure was shown to be an efficient, rapid, inexpensive and eco-friendly method for the determination of lead, chromium and cadmium in herbal medicines. Application of the USAEME method leads to an increased extraction efficiency with satisfactory precision in a short time using an extraction solvent volume at the microlitre level. Copyright © 2015 John Wiley & Sons, Ltd.

Posted on 9 January 2015 | 12:23 pm

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