This is the first report on identification of all B-type proanthocyanidins from monomers to decamers (monomers-flavan-3-ols, dimers, trimers, tetramers, pentamers, hexamers, heptamers, octamers, ...nonamers, and decamers) and some of their gallates in leaves of Japanese knotweed (
Houtt.), giant knotweed (
F. Schmidt) and Bohemian knotweed (
×
(Chrtek & Chrtkova) J.P. Bailey). Flavan-3-ols and proanthocyanidins were investigated using high performance thin-layer chromatography (HPTLC) coupled to densitometry, image analysis, and mass spectrometry (HPTLC-MS/MS). All species contained (-)-epicatechin and procyanidin B2, while (+)-catechin was only detected in Bohemian and giant knotweed. (-)-Epicatechin gallate, procyanidin B1 and procyanidin C1 was only confirmed in giant knotweed. Leaves of all three knotweeds have the same chemical profiles of proanthocyanidins with respect to the degree of polymerization but differ with respect to gallates. Therefore, chromatographic fingerprint profiles of proanthocyanidins enabled differentiation among leaves of studied knotweeds, and between Japanese knotweed leaves and rhizomes. Leaves of all three species proved to be a rich source of proanthocyanidins (based on the total peak areas), with the highest content in giant and the lowest in Japanese knotweed. The contents of monomers in Japanese, Bohemian and giant knotweed were 0.84 kg/t of dry weight (DW), 1.39 kg/t DW, 2.36 kg/t, respectively, while the contents of dimers were 0.99 kg/t DW, 1.40 kg/t, 2.06 kg/t, respectively. Giant knotweed leaves showed the highest variety of gallates (dimer gallates, dimer digallates, trimer gallates, tetramer gallates, pentamer gallates, and hexamer gallates), while only monomer gallates and dimer gallates were confirmed in Japanese knotweed and monomer gallates, dimer gallates, and dimer digallates were detected in leaves of Bohemian knotweed. The profile of the Bohemian knotweed clearly showed the traits inherited from Japanese and giant knotweed from which it originated.
Flavan-3-ols and proanthocyanidins of invasive alien plants Japanese knotweed (
Houtt.), giant knotweed (
F. Schmidt) and Bohemian knotweed (
×
(Chrtek & Chrtkova) J.P. Bailey) were investigated ...using high performance thin-layer chromatography (HPTLC) coupled to densitometry, image analysis and mass spectrometry (HPTLC-MS/MS). (+)-Catechin, (-)-epicatechin, (-)-epicatechin gallate and procyanidin B2 were found in rhizomes of these three species, and for the first time in Bohemian knotweed. (-)-Epicatechin gallate, procyanidin B1, procyanidin B2 and procyanidin C1 were found in giant knotweed rhizomes for the first time. Rhizomes of Bohemian and giant knotweed have the same chemical profiles of proanthocyanidins with respect to the degree of polymerization and with respect to gallates. Japanese and Bohemian knotweed have equal chromatographic fingerprint profiles with the additional peak not present in giant knotweed. Within the individual species giant knotweed rhizomes and leaves have the most similar fingerprints, while the fingerprints of Japanese and Bohemian knotweed rhizomes have additional peaks not found in leaves. Rhizomes of all three species proved to be a rich source of proanthocyanidins, with the highest content in Japanese and the lowest in Bohemian knotweed (based on the total peak areas). The contents of monomers in Japanese, Bohemian and giant knotweed rhizomes were 2.99 kg/t of dry mass (DM), 1.52 kg/t DM, 2.36 kg/t DM, respectively, while the contents of dimers were 2.81 kg/t DM, 1.09 kg/t DM, 2.17 kg/t DM, respectively. All B-type proanthocyanidins from monomers to decamers (monomers-flavan-3-ols, dimers, trimers, tetramers, pentamers, hexamers, heptamers, octamers, nonamers and decamers) and some of their gallates (monomer gallates, dimer gallates, dimer digallates, trimer gallates, tetramer gallates, pentamer gallates and hexamer gallates) were identified in rhizomes of Bohemian knotweed and giant knotweed. Pentamer gallates, hexamers, hexamer gallates, nonamers and decamers were identified for the first time in this study in Bohemian and giant knotweed rhizomes.
Structural and Functional Analysis of Extracts in Plants collects 1 editorial, 3 reviews, and 26 research articles reporting recent research findings which cover several aspects of plant-derived ...bioactive compounds, to correlate extraction techniques with the chemical composition of extracts and their bioactivity for identifying molecules that might be used as active substances in a wide variety of areas.This book is a valuable resource for members of the scientific community wishing to further explore plants and the therapeutic applications of their bioactive compounds. It will appeal to scholars, teachers and scientists involved in plant product research, and facilitate the development of innovative new drugs.
Melamine containing large amount of nitrogen may be deliberately added to milk in order to increase the protein content for economic adulteration in food stuffs. High performance thin layer ...chromatography-mass spectrometry (HPTLC-MS)-based method of quantification of melamine has been developed using Silica gel 60 F₂₅₄ₛ HPTLC plates, with optimized mobile phase iso-propanol/dichloromethane/water, 5:2.5:3, v/v/v in a twin trough chamber saturated (5 min) at pH 6.8. Validation was carried out by testing its specificity, linearity (1–50 μg), accuracy (95.908–98.369%), inter- and intraday precision (1.578 and 1.670%), respectively, limits of detection (2.688 ng) and quantification (8.146 ng). HPTLC in combination with MS has been found suitable for routine analysis of melamine added as adulterant to market-purchased milk samples.
An approach for rapid quantitation of 5-hydroxymethylfurfural (HMF) in honey using planar chromatography is suggested for the first time. In high-performance thin-layer chromatography (HPTLC) the ...migration time is approximately 5 min. Detection is performed by absorbance measurement at 290 nm. Polynomial calibration in the matrix over a range of 1:80 showed correlation coefficients,
r
, of ≥ 0.9997 for peak areas and ≥ 0.9996 for peak heights. Repeatability in the matrix confirmed the suitability of HPTLC–UV for quantitation of HMF in honey. The relative standard deviation (
RSD
, %,
n
= 6) of HMF at 10 ng/band was 2.9% (peak height) and 5.2% (peak area); it was 0.6% and 1.0%, respectively, at 100 ng/band. Other possible detection modes, for example fluorescence measurement after post-chromatographic derivatization and mass spectrometric detection, were also evaluated and can coupling can be used as an additional tool when it is necessary to confirm the results of prior quantitation by HPTLC–UV. The confirmation is provided by monitoring the HMF sodium adduct M + Na
+
at
m
/
z
149 followed by quantitation in TIC or SIM mode. Detection limits for HPTLC–UV, HPTLC–MS (TIC), and HPTLC–MS (SIM) were 0.8 ng/band, 4 ng/band, and 0.9 ng/band, respectively. If 12 μL honey solution was applied to an HPTLC plate, the respective detection limits for HMF in honey corresponded to 0.6 mg kg
−1
. Thus, the developed method was highly suitable for quantitation of HMF in honey at the strictest regulated level of 15 mg kg
−1
. Comparison of HPTLC–UV detection with HPTLC–MS showed findings were comparable, with a mean deviation of 5.1 mg kg
−1
for quantitation in SIM mode and 6.1 mg kg
−1
for quantitation in TIC mode. The mean deviation of the HPTLC method compared with the HPLC method was 0.9 mg kg
-1
HMF in honey. Re-evaluation of the same HPTLC plate after one month showed a deviation of 0.5 mg kg
−1
HMF in honey. It was demonstrated that the proposed HPTLC method is an effective method for HMF quantitation in honey.
Figure
Fast quantitation of 5-hydroxymethylfurfural in honey
Background
Ecstasy is one of the popular illicit drugs in the world and its usage has been recently increased in Iran. This compound can destroy the serotonergic neurons and produces cognitive and ...psychopathology diseases. 3,4-dihydroxymethamphetamine (HHMA) which is the main metabolite of this compound, seems to be responsible for this effect. However, no consensus has been reached among the researchers about its role. This disagreement between the researches may be due to failure in determination of HHMA as free form in physiological fluids. In this study, the stability of this crucial metabolite of ecstasy was examined in different mediums.
Methods
The stability of HHMA was studied in the perfusion medium and water at 100 and 10 ng/mL concentrations. Moreover, the effect of temperature (0–25°C), pH (3–10), calcium chloride (0–150 g/L) and ethylenediaminetetraacetic acid (EDTA) on the stability of HHMA was also examined.
Results
Our result suggested that the free form of HHMA could be degraded in the perfusion medium. The rate of this degradation has direct proportion to temperature (at 25°C = 0.037 min
-1
and at 0°C = 0.002 min
-1
). Calcium chloride and sodium bicarbonate are two responsible components in this instability. Moreover, the alkaline pHs and increasing the shaking time can accelerate this effect. Although, while degradation was prevented at pH=3, EDTA could only reduce this rate about 30%.
Conclusions
Calcium cation can act as an accelerator of HHMA degradation. Therefore, the perfusion medium should not contain Ca
2+
and the pH of medium is better to be adjusted at acidic range. Since, the internal cellular source of calcium is endoplasmic reticulum system, it can be assumed that, this cation may change HHMA and dopamine to reactive compounds that can bind covalently to the cysteinyl group of biological compounds and damage cellular components.
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