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1.
Wesołowski M. Konieczyński P. Ulewicz-Magulska B. 《Journal of Thermal Analysis and Calorimetry》2001,66(2):593-601
Studies on the thermal decomposition of commercial raw plant materials used in medicine were performed. 144 independent samples
of plant materials — herbs, leaves,flowers, inflorescences, fruits, roots, rhizomes and barks, collected by Medicinal Plant
Works‘Herbapol’, were analyzed. Thermal decomposition was performed using OD-103 Derivatograph. As a result of analysis, it
was established, that thermal decomposition of majority of samples proceeds through three stages. The analysis of fruits revealed,
that their thermal decomposition proceeds in four stages. In order to obtain a more clear classification of the analyzed plant
materials principal component analysis (PCA) was applied. Interpretation of the PCA results allows to state, that samples
of raw materials from the same plant species in majority of cases are characterized by similar course of thermal decomposition
due to similar chemical composition. In this way the differences in general chemical composition of medicinal
plants raw materials can be determined.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
M. Wesołowski P. Konieczyński B. Ulewicz 《Journal of Thermal Analysis and Calorimetry》2000,60(1):299-304
Studies on the thermal decomposition and on the elemental composition of commercial raw plant materials used in medicine were
performed. 16independent samples of fruits originating from 12 medicinal plant species collected in1988–92 were analysed.
The thermal decomposition was performed using the derivatograph. The content of non-metallic (N, P, S, Cl, I and B) and metallic
(Ca, Mg, Fe, Mn, Cu and Zn)elements was determined by spectrophotometric techniques after previous mineralization of sample.
In order to obtain more clear classification of the analysed plant materials principal component analysis was applied. The
interpretation of PCA results for three databases (thermoanalytical, non-metals and metals data sets) allows to state, that
samples of fruits from the same plant species in the majority of cases are characterized by similar elemental composition
and similar course of their thermal decomposition. In this way the differences in general chemical composition of medicinal
plants raw materials can be determined.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Wesolowski M Suchacz B Konieczynski P 《Combinatorial chemistry & high throughput screening》2003,6(8):811-820
In the present study three thermoanalytical methods: differential thermal analysis (DTA), thermogravimetric analysis (TGA), and derivative thermogravimetric analysis (DTG) were used to investigate the thermal behavior of medicinal plant raw materials. In order to describe DTA curve, designation of the onset T(i), and peak T(p), temperatures was required. In TGA the mass losses Delta(m), and in DTG the temperature range of peak DeltaT, peak temperature T(p), and peak height h, were recorded. All parameters were read for three stages of the thermal decomposition of plant samples which resulted in obtaining eighteen thermal variables for each sample. Some similarities in the course of thermal decomposition of the same plant organs were recognized, but complexity of the obtained data made it very difficult to determine if they could differentiate between medicinal plant materials and which of them encode the most valuable information about the studied herbals. In order to confirm the existence of any relations between the chemical composition of medicinal plants and their thermal decomposition and to find out which thermoanalytical variables or decomposition stages can be considered as the most significant in terms of their evaluation, it was decided to apply fully connected feed-forward artificial neural networks (ANN). Two different training algorithms were used to address the problem: back-propagation of error and conjugate gradient descent. To verify the results two-dimensional (2-D) Kohonen self-organizing feature maps (SOFMs) were employed. Two alternative datasets of thirteen key variables discriminating plant samples have been proposed. 相似文献
4.
Erika Mészáros Emma Jakab G. Várhegyi P. Tóvári 《Journal of Thermal Analysis and Calorimetry》2007,88(2):477-482
The aim of this work was to study the thermal
decomposition of different plant species obtained from energy plantations.
Thermogravimetry/ mass spectrometry (TG/MS) experiments have been performed
with two herbaceous crops (Miscanthus sinensis,
pelletized energy grass) and two wood samples (willow, water locust) in inert
and oxidative atmospheres. Owing to the large number of data obtained in the
experiments, a chemometric tool, principal component analysis (PCA) has been
used to help the interpretation of the results. It has been found that the
thermal decomposition of the studied wood species is similar, whereas that
of the studied herbaceous samples exhibits significant differences. PCA has
been found to be useful for finding correlations between the various experimental
data. 相似文献
5.
Zoltán Sebestyén Zoltán May Kati Réczey Emma Jakab 《Journal of Thermal Analysis and Calorimetry》2011,105(3):1061-1069
The goal of this study was to clarify the effect of alkaline pretreatments on the thermal decomposition and composition of
industrial hemp (Cannabis sativa L.) samples. Thermogravimetric/mass spectrometric measurements (TG/MS) have been performed, on untreated, hot water washed,
and alkali-treated hemp samples. The main differences between the thermal decomposition of the samples are interpreted in
terms of the different alkali ion contents which have been determined using inductively coupled plasma-optical emission spectroscopy
(ICP-OES) method. Principal component analysis (PCA) has been used to find statistical correlations between the data. Correlations
have been obtained between the parameters of the thermal decomposition and the alkali ion content as well as the altered chemical
structure of the samples. The differences in the thermal behavior of the samples are explained by the different K+ and Na+ contents and the changed structure of the hemicellulose component of the samples due to the pretreatments. The more alkali
ions remain in the hemp samples after the alkali treatment, the more ash, char and lower molecular products are formed during
thermal decomposition. 相似文献
6.
Several Polygonatum species are important medicinal materials as tonic to cure disorders in China. Because of their different medical effects, it is desired to distinguish them at species level. In addition, to ensure and control their medical quality, it is also important to monitor their chemical changes associated with traditional process. Taking the advantages of Fourier transform infrared spectroscopy (FT-IR) and multivariate analysis, we developed a convenient, fast and reliable approach to discriminate and quality control these materials. Despite similar absorption patterns, each species also presented spectral differences, especially on the FT-IR fingerprint range of 1800-600 cm−1. Second derivative method obviously enlarged those differences and then showed more species-specific features. These spectral differences could be used as powerful discriminating points to distinguish them. PCA results showed that each species separated clearly with their biological replicates grouped together, which indicated that the variance between species is greater than within species, therefore, these species could be distinguishable. Using this approach, the five herbal materials were discriminated successfully in their raw, processed and ethanol extracted formats. On the other hand, visual inspecting infrared spectra of samples from 1 to 9 process steps, absorbance near 1737, 1259, 817 and 780 cm-1 increased gradually but decreased gradually at 927 cm−1. Besides, spectral contour near 1050 cm−1 changed sharply with process treatment. These spectral changes indicated that hydrolyzing polysaccharides into oligo- and mono-saccharides, especially glucose and fructose, are the main chemical changes associated with traditional process. This is consistent with the traditional experience that the processed materials are dark as night and sweet as malt sugar. Meanwhile, our results also indicated that their chemical constituents changed profoundly after process, which might be the chemical basis for raw and processed materials have different medical effects. Based on absorbance at 817 and 780 cm−1 and the color, taste, smell of processed materials followed by energy efficacy, raw materials had to be processed more than 21 h to ensure their quality. This research shows the potential of FT-IR spectroscopy coupled with multivariate analysis to discriminate different herbs and to monitor chemical changes with process and then control their quality. This could be very helpful to ensure the quality, safety, and efficacy of herbs on clinical practices. 相似文献
7.
I. O. Abugassa A. T. Bashir K. Doubali R. H. Etwir M. Abu-Enawel S. O. Abugassa 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(3):559-563
Medicinal herbs are often used as alternative medicines for healing and controlling some diseases in the world. This study
focuses on the content of heavy and trace elements of some widely consumed herbs in Libya. Nine most popular herbs were analyzed
by k
0-instrumental neutron activation analysis. All the samples, SRM and flux monitors were irradiated for 7 and 10 hours under
thermal neutron flux of 1.3·1013 cm−2·s−1 at Tajoura nuclear reactor. In total, 33 elements were analyzed in different herbs. The variations in the concentration of
the elements are attributed to soil composition and the climate in which the plant grows. The study showed that the toxic
elements found in the samples were below the levels prescribed by health regulations. The precision and the accuracy of the
results were evaluated by analyzing the reference materials Pine Needles SRM 1575 and Citrus Leaves SRM1572. 相似文献
8.
The thermal decomposition of theophylline, theobromine, caffeine, diprophylline and aminophylline were evaluated by calorimetrical,
thermoanalytical and computational methods. Calorimetrical studies have been performed with aid of a heat flux Mettler Toledo
DSC system. 10 mg samples were encapsulated in a 40 μL flat-bottomed aluminium pans. Measurements in the temperature range
form 20 to 400°C were carried out at a heating rate of 10 and 20°C min−1 under an air stream. It has been established that the values of melting points, heat of transitions and enthalpy for methylxanthines
under study varied with the increasing of heating rate.
Thermoanalytical studies have been followed by using of a derivatograph. 50, 100 and 200 mg samples of the studied compounds
were heated in a static air atmosphere at a heating rate of 3, 5, 10 and 15°C min−1 up to the final temperature of 800°C. By DTA, TG and DTG methods the influence of heating rate and sample size on thermal
destruction of the studied methylxanthines has been determined. For chemometric evaluation of thermoanalytical results the
principal component analysis (PCA) was applied. This method revealed that first of all the heating rate influences on the
results of thermal decomposition. The most advantageous results can be obtained taking into account sample masses and heating
rates located in the central part of the two-dimensional PCA graph. As a result, similar data could be obtained for 100 mg
samples heated at 10°C·min−1 and for 200 mg samples heated at 5°C min−1. 相似文献
9.
The objective of the paper was to verify if the content of some elements provides enough information for proper classification of the medicinal plant raw materials. Such information could be helpful in standardization process of herbal products. Four elements—zinc, copper, lead and cadmium were determined using inverse voltammetry in commercially available medicinal herbal raw materials. Initially, principal component analysis (PCA) was employed to investigate the relationships among the analyzed trace elements. In the next stage of the study, two different types of feed-forward artificial neural networks (FANNs)—multilayer perceptron (MLP) and radial basis function (RBF) were applied. The concentrations of the elements were used as input variables to neural networks models, which were to recognize the taxonomy of the plant and the anatomical part it originated from. Although full recognition of the samples with use of FANNs on the basis of some trace elements content was not achieved, it was possible to identify two elements—cadmium and lead as the most important in the classification analysis of medicinal plants. 相似文献
10.
The thermal decomposition of benzoic acid and its derivatives containing —OH, —NH2, —COOH and —SO3H functional groups as substituents in ortho, meta and (or) para position together with sulphanilic acid was investigated.
The analyses were performed using derivatograph, sample mass ranged from 50 to 200 mg, heating rates from 3 to 15 K min−1 and static air atmosphere. It has been established that thermal decomposition of these aromatic acids proceeds through three
common stages. In the first stage the phase transformations occur. The following two stages are due to the formation of intermediate
products of the thermal decomposition and their combustion. Principal component analysis (PCA) was applied for evaluation
of the results. Thanks to this method the influence of specific functional groups and their positions on the benzene ring
on the thermal decomposition of the compounds under investigation was determined.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Piotr Szynkaruk Marek Wesolowski Malgorzata Samson-Rosa 《Journal of Thermal Analysis and Calorimetry》2010,102(2):505-512
Thermal decomposition of magnesium salts of organic acids used in medicine (Mg acetate, Mg valproate, Mg lactate, Mg citrate,
Mg hydrogen aspartate, Zn hydrogen aspartate) was analyzed by thermoanalytical, calorimetrical, and computational methods.
Thermoanalytical studies were performed with aid of a derivatograph. 50-, 100-, and 200-mg samples were heated in a static
air atmosphere at a heating rate of 3, 5, 10, and 15 °C min−1 up to the final temperature of 700–900 °C. By differential thermal analysis (DTA), thermogravimetry (TG), and derivative
thermogravimetry (DTG) methods, it has been established that thermal decomposition of the salts under study occurs via two
stages. The first stage (dehydratation) was distinctly marked on the thermoanalytical curves. Calorimetrical studies were
carried out by using of a heat-flux Mettler Toledo differential scanning calorimetry (DSC) system. Ten milligram samples of
compounds under study were heated in the temperature range from 20 to 400 °C at a heating rate of 10 and 20 °C min−1 under an air stream. The studies showed that the values of transitions heats and enthalpies of dehydration for investigated
salts varied with the increasing of heating rate. For chemometric evaluation of thermoanalytical results, the principal component
analysis (PCA) was applied. This method revealed that points on PC1 versus PC2 diagrams corresponding to the compounds of
similar chemical constitution are localized in the similar ranges of the first two PC’s values. This proves that thermal decomposition
reflects similarity in the structure of magnesium salts of organic acids. 相似文献
12.
Agnieszka Arceusz Marek Wesolowski Iwona Radecka 《Central European Journal of Chemistry》2011,9(5):917-924
The concentrations of seven macro- and microelements (K, Mg, Ca, Na, Fe, Zn, Mn) in 59 herbs (herbs, leaves, flowers, fruits,
roots), which are commercially available and frequently used in Poland for medical purposes as well as in their water extracts
(infusions and decoctions), were determined after microwave mineralization. The data obtained show that all herbal raw materials
analysed contain macroelements in the range of mg g−1 on d.w. whereas microelements in the range of mg kg−1 on d.w. and that elemental concentrations varied widely. On the basis of a comparison of concentrations of elements in herbal
raw materials examined and water extracts prepared from them, the extraction efficiency was expressed as a percent of the
total content of each element present in the infusion or decoction. The percentages of macro- and micro- elements leaching
from different morphological parts of plants into water extracts varied across a wide range of values, from 1% in the case
of Na to 56% in the case of K. Real daily intake of the macro- and microelements elements through one cup of infusions or
decoctions were shown that water extracts from herbal raw materials are not an important source of bioelements in human diet.
相似文献
13.
Electrospray ionization ion trap multiple-stage tandem mass spectrometry (ESI-MS(n)) was used to evaluate Fructus Schisandrae of similar species (Schisandra chinensis (Turcz.) Baill. fruits and Schisandra sphenanthera Rehd. et Wils. fruits) and different growth characteristics (color, shape, etc.). The application of chemical pattern recognition in the ESI-MS(n) data analysis was carried out by principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). Then the antioxidant activity of different Fructus Schisandrae samples were determined by an LC-ESI-MS method and ferric reducing antioxidant power (FRAP) assay. Using the ESI-MS(n) method coupled with chemical pattern recognition analysis and correlated with the antioxidant activity evaluation, the two similar species were successfully distinguished, thus improving the therapeutic safety and effectiveness. The superior characteristics of Schisandra chinensis (Turcz.) Baill. fruits were obtained and made the selection and breeding of Chinese medicine materials more scientific. This study indicates that ESI-MS(n) is a valuable tool for the authentication of botanical origin and can also be useful for the quality control of Chinese medicinal herbs. 相似文献
14.
Dencichine (beta-N-oxalyl-L-alpha,beta-diaminopropionic acid) is a haemostatic agent present in important Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species. It is also a reported neurotoxic agent found in Lathyrus sativus (grass pea seed). A selective analytical method incorporating hydrophilic interaction chromatography with positive electrospray ionization tandem mass spectrometry (HILIC/ESI-MS/MS), for the analysis of dencichine in Panax plant species, was developed. Using multiple reaction monitoring (MRM) mode, underivatized dencichine, a small and highly polar compound, was selectively detected and quantified. The contents of dencichine in raw and steamed Panax notoginseng roots, 11 pairs of raw and steamed P. notoginseng herbal products, Panax ginseng roots, and Panax quinquefolium roots, were analyzed and compared. Optimal sensitivity of 0.3 ppm (detection limit) and 1.5 ppm (quantification limit) was achieved. The method was rapid (< or =5 min), with the HILIC peak eluting at about 1 min. Steamed P. notoginseng samples were found to contain less dencichine than the corresponding raw samples, and there were also differences among the three Panax species; raw P. ginseng and P. quinquefolium contained less dencichine than the raw P. notoginseng species. This rapid and specific method may be applied to the quantification of dencichine in complex medicinal plants and their products. 相似文献
15.
The influence of substituents on the thermal decomposition of monomeric organic compounds was studied. For this purpose the
thermal destruction of dozen or so α-amino acids of the diversified chemical constitution, among others compounds containing
the second amine group, additional carboxyl group, amino acids containing hydroxyl or sulfhydryl groups and amino acids connected
with five-member heterocyclic ring or existing in the form of hydrates or hydrochlorides were investigated. The analyses were
performed using a derivatograph in an air atmosphere, sample sizes were from 50 to 200 mg and heating rate from 3 to 15 K
min-1. It has been established that the thermal decomposition of studied compounds occurs in three stages. The temperature ranges,
in which the analyzed compounds undergo thermal transformations were established. For evaluation of the thermoanalytical results
an advanced multivariate data processing method, principal component analysis (PCA), was used. By this method the influence
of the specific functional groups on the thermal decomposition of α-amino acids was determined. The stage of decomposition,
in which the thermoanalytic data are the best correlated to the chemical constitution of the compound, is the second stage.
It has also been recognized, that better discrimination among the analyzed compounds was obtained for the data set of the
DTA. 相似文献
16.
R. V. Razzhivin V. Yu. Reshetnyak A. N. Kuz’menko O. V. Nesterova V. A. Popkov 《Moscow University Chemistry Bulletin》2009,64(1):55-57
The composition of the volatile fraction of extracts for pharmacopoeial types of medicinal plant raw materials was studied using chromatography-mass spectrometry to identify specific compounds characteristic of a specific plant. Forty pharmacopoeial types of medicinal plant raw material were analyzed. It is shown that 14 of them contain specific volatile compounds (markers) allowing unambiguous identification. 相似文献
17.
Stefano Vecchio Romolo Di Rocco Carla Ferragina 《Journal of Thermal Analysis and Calorimetry》2009,97(3):805-810
The thermal behaviour of the complexes formed in situ between the aromatic diamine 1,10-phenanthroline and the Co(II) and
Ni(II) ions intercalated between the layers of γ-zirconium phosphate was studied by simultaneous TG/DSC techniques. The obtained
materials show similar thermal behaviour: after a multi-step dehydration process they showed an oxidative decomposition in
only one step. The kinetic study of the decomposition process was performed using both the model-free methods of Ozawa-Flynn-Wall
and Kissinger. The former method provides a negligible dependence of activation energy on the degree of reaction α for both
materials. Activation energies derived by the Kissinger method show a good agreement with the mean values derived by the Ozawa-Flynn-Wall
method. The Arrhenius rate constants determined using also the pre-exponential factor values demonstrate that their thermal
stability can be considered comparable, within the experimental uncertainty. Finally, a reliable method was applied to determine
the model function from the best fit between the numerical dependence of the integral function g(α) vs. α and several theoretical model dependencies reported in literature for the most commonly used models. A Mampel first-order
reaction model was selected to describe the thermal decomposition in both the materials studied. 相似文献
18.
V. V. Nedel'ko A. V. Shastin B. L. Korsunskii N. V. Chukanov T. S. Larikova A. I. Kazakov 《Russian Chemical Bulletin》2005,54(7):1710-1714
Ditetrazol-5-ylamine (DTA) was synthesized from cyanuric chloride in four steps. The thermal decomposition of DTA in the solid
state was studied by thermogravimetry, volumetry, mass spectrometry, IR spectroscopy, and calorimetry. Under isothermal conditions
at 200–242 °C, thermal decomposition obeys the first order autocatalytic kinetics. The kinetic and activation parameters of
DTA decomposition were determined. The composition of gaseous reaction products and the structure of condensed residue were
studied. The thermal effect of thermal DTA decomposition is 281.4 kJ mol−1. The nitrogen content in a mixture of gaseous products formed by the reaction in a temperature interval of 200–242 °C exceeds
97 vol.%.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1660–1664, July, 2005. 相似文献
19.
Robson Santana Lima Arnaud Victor dos Santos Fabiano Vargas Pereira Marluce Oliveira da Guarda Souza 《Journal of Thermal Analysis and Calorimetry》2010,100(1):83-87
The thermal decomposition process of La2O3/MgO (La/Mg = 2, 1 and 0.5) supported nickel (15% mass/mass Ni) precursor was investigated. Thermal analysis results show
distinct processes of decomposition of the samples in accordance with the composition. The mass loss at higher temperature
is associated to distinct stages of decomposition of lanthanum precursors. The thermal analysis results agree with the FTIR
spectra showing change in the band corresponding to carbonates and nitrates species. XRD results also confirmed the precursor’s
decomposition. It can be concluded that the thermal decomposition of La2O3–MgO-nickel precursor depends on the La/Mg ratio and of the residual species. 相似文献
20.
Isoquinoline alkaloids (papaverine, noscapine, berberine, emetine, and quinine) were determined in medicinal plants and herbs used in Traditional Chinese Medicine and Ayurveda by liquid chromatography with tandem mass spectrometry detection (LC-MS/MS). The analyzed alkaloids were separated at gradient conditions using methanol and 2% acetic acid within 12?min. The validated method was successfully applied for 17 herbal samples: Ashwagandha, Astragalus membranaceus, Emblica officinalis, Mucuna pruriens, Pueraria lobata, Ocimum sanctum, Rehmannia glutinosa, Schisandra sinensis, Terminalia arjuna, Terminalia chebula, and dietary supplements. The highest concentration of studied alkaloids was observed for berberine in Puearia lobata (6.68?±?0.62?mg 100?g?1 d.m.), while the lowest value was obtained for noscapine in a dietary supplement containing Terminalia arjuna (0.09?±?0.01?mg 100?g?1 d.m.). Principal component analysis, cluster analysis, and one-way ANOVA tests were also performed. The results indicate the need to control plant materials and dietary supplements in terms of the content of alkaloids and toxic components. 相似文献