Development of a liquid chromatography tandem mass spectrometry method for simultaneous determination of eight adulterants in slimming functional foods

Photodegradation and In Silico Molecular Docking Study of a Diuretic Drug: Clopamide

Clopamide (CPD, 1) is a piperidine and sulfamoylbenzamide-based diuretic drug and a potential photosensitizing sulfonamide; its phototransformation was investigated using N,N-dimethylaniline (DMA) as an electron donor and 1,4-dicyanonaphthalene (DCN) as an electron acceptor in an immersion-well-type photochemical reactor fitted with a medium-pressure mercury vapor lamp (450 W). Photodegradation of the drug Clopamide resulted in two significant products via photoinduced electron transfer. Structures of these products were deduced from their 1H NMR, 13C NMR, mass, and IR spectra. The photoproducts are 2- choloro-5-((2,6-dimethylpiperidin-1-yl)carbamoyl)benzenesulfonic acid (2) and 4-hydroxy-N-(2,6-dimethyl-1-piperidyl)-3-sulfamoyl benzamide (3). In addition to this, the comparative antioxidant potentials of the parent drug and its photoproducts were investigated using in silico molecular docking against tyrosinase in order to better understand the in vivo relevance of pharmacological action of the drug as a result of light-drug interactions. UV light has been observed to modify substituents on the benzene ring, hence loss of biological activity at the time of storage and in vivo cannot be ruled out. This suggests that Clopamide users should avoid light (natural or artificial) exposure to prevent from drug-induced photosensitivity.

Assessment of Undeclared Synthetic Drugs in Dietary Supplements in an Analytical View: A Comprehensive Review

Dietary supplements have gained widespread attention globally as they are supposed to be healthier than synthetic pharmaceutical compounds with fewer side effects. Unlike common prescription drugs, dietary supplements are readily available to the general public. However, over the past few years, all kinds of legal and illegal drugs, have been detected in dietary supplements without labeling to defraud consumers, resulting in serious public health consequences. Due to the increasing number of drug frauds in dietary supplements, their consumption will undoubtedly risk consumers. Therefore; the importance of high-tech analytical methods in their assessment for controlling food quality seems undeniable. The current review examines the analytical techniques that focus on adulterating health products with undeclared pharmaceuticals, including registered and banned drugs. The present study referred to a survey from 2004 to 2021 based on articles in the Scopus database.

Validation of a rapid and simple high-performance liquid chromatography-electrospray ionization-mass spectrometry method for simultaneous analysis of 15 key chemicals in slimming foods and herbal products

A rapid and simple high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed for simultaneous analysis of 15 key chemicals in slimming foods and herbal products. These chemicals were strictly restricted adulterants (phenolphthalein, sibutramine, fenfluramine, clopamide, ephedrine, norpseudoephedrine, caffeine and phenformin) and physiologically relevant active components (l-carnitine, nuciferine, aloe-emodin, rhein, emodin, chrysophanol and physcion). In multi-day validations, intra- (n = 5) and inter-day precision (n = 3), limits of detection and limits of quantification for all analytes were 0.60-7.22%, 0.75-9.45%, 0.09-10 μg/L and 0.30-33.3 μg/L, respectively. Mean recovery ranged from 71.4% to 116% for all analytes in three representative samples. The method was validated on 17 samples including 12 kinds of slimming foods and five kinds of herbal products, and was shown to be ideal for routine quantification of 15 key chemicals in slimming foods and herbal products, providing an efficient strategy for quality control and food safety evaluation of weight reducing supplements.

Suspected Adulteration of Commercial Kratom Products with 7-Hydroxymitragynine

INTRODUCTION

Kratom (Mitragyna speciosa), a plant native to Southeast Asia, has been used for centuries for its stimulant and opium-like effects. Mitragynine and 7-hydroxymitragynine, exclusive to M. speciosa, are the alkaloids primary responsible for Kratom's biologic and psychoactive profile, and likely contribute to its problematic use. We purchased several commercially available Kratom analogs for analysis and through our results, present evidence of probable adulteration with the highly potent and addictive plant alkaloid, 7-hydroxymitragynine.

METHODS

A simple and sensitive LC-MS/MS method was developed for simultaneous quantification of mitragynine and 7-hydroxymitragynine in methanol extract of marketed Kratom supplements.

RESULTS

We found multiple commercial Kratom products to have concentrations of 7-hydroxymitragynine that are substantially higher than those found in raw M. speciosa leaves.

CONCLUSIONS

We have found multiple packaged commercial Kratom products likely to contain artificially elevated concentrations of 7-hydroxymitragynine, the alkaloid responsible for M. speciosa's concerning mechanistic and side effect profile. This study describes a unique form of product adulteration, which stresses the importance of increased dietary supplement oversight of Kratom-containing supplements.

KdmB, a Jumonji Histone H3 Demethylase, Regulates Genome-Wide H3K4 Trimethylation and Is Required for Normal Induction of Secondary Metabolism in Aspergillus nidulans

Histone posttranslational modifications (HPTMs) are involved in chromatin-based regulation of fungal secondary metabolite biosynthesis (SMB) in which the corresponding genes—usually physically linked in co-regulated clusters—are silenced under optimal physiological conditions (nutrient-rich) but are activated when nutrients are limiting. The exact molecular mechanisms by which HPTMs influence silencing and activation, however, are still to be better understood. Here we show by a combined approach of quantitative mass spectrometry (LC-MS/MS), genome-wide chromatin immunoprecipitation (ChIP-seq) and transcriptional network analysis (RNA-seq) that the core regions of silent A. nidulans SM clusters generally carry low levels of all tested chromatin modifications and that heterochromatic marks flank most of these SM clusters. During secondary metabolism, histone marks typically associated with transcriptional activity such as H3 trimethylated at lysine-4 (H3K4me3) are established in some, but not all gene clusters even upon full activation. KdmB, a Jarid1-family histone H3 lysine demethylase predicted to comprise a BRIGHT domain, a zinc-finger and two PHD domains in addition to the catalytic Jumonji domain, targets and demethylates H3K4me3 in vivo and mediates transcriptional downregulation. Deletion of kdmB leads to increased transcription of about ~1750 genes across nutrient-rich (primary metabolism) and nutrient-limiting (secondary metabolism) conditions. Unexpectedly, an equally high number of genes exhibited reduced expression in the kdmB deletion strain and notably, this group was significantly enriched for genes with known or predicted functions in secondary metabolite biosynthesis. Taken together, this study extends our general knowledge about multi-domain KDM5 histone demethylases and provides new details on the chromatin-level regulation of fungal secondary metabolite production.

In this work we monitored by proteomic analysis and ChIP-seq the genome-wide distribution of several key modifications on histone H3 in the model fungus Aspergillus nidulans cultivated either under optimal physiological conditions (active growth) or less favourable conditions which are known to promote the production of secondary metabolites (SM). When we correlated the chromatin status to transcriptional activities in actively growing cells we found that the silenced SM gene clusters are flanked by heterochromatic domains presumably contributing to silencing but that the bodies of the clusters only carry background levels of any of the investigated marks. In nutrient-depleted conditions, activating marks were invading some, but by far not all transcribed clusters, leaving open the question how activation of these regions occurs at the chromatin level. Surprisingly, a large number of these gene clusters actually depend on KdmB for normal activation and it will be interesting to see in future how this protein thought to mainly act as repressor by removing positive H3K4m3 marks switches gears to activate transcription directly or indirectly.

Negative ion electrospray high-resolution tandem mass spectrometry of polyphenols

Representative compounds with a 1,3-dihydroxybenzene substructure belonging to different important polyphenol classes (stilbenes, flavones, isoflavones, flavonols, flavanones, flavanols, phloroglucinols, anthraquinones and bisanthraquinones) were investigated based on detailed high-resolution tandem mass spectrometry measurements with an Orbitrap system under negative ion electrospray conditions. The mass spectral behaviour of these compound classes was compared among each other not only with respect to previously described losses of CO, CH2 CO and C3 O2 but also concerning the loss of CO2 and successive specific fragmentations. Furthermore, some unusual fragmentations such as the loss of a methyl radical during mass spectral decomposition are discussed. The obtained results demonstrate both similarities and differences in their mass spectral fragmentation under MS(n) conditions, allowing a characterization of the corresponding compound type. Copyright © 2015 John Wiley & Sons, Ltd.

Adulteration of Dietary Supplements by the Illegal Addition of Synthetic Drugs: A Review

In the last few years, the consumption of dietary supplements, especially those having plants as ingredients, has been increasing due to the common idea that they are natural products posing no risks to human health. In the European Union and the United States, dietary supplements are legally considered as foods/special category of foods, thus are not being submitted to any safety assessment prior to their commercialization. Among the issues that can affect safety, adulteration by the illegal addition of pharmaceutical substances or their analogs is of major concern since unscrupulous producers can falsify these products to provide for quick effects and to increase sales. This review discusses the various classes of synthetic drugs most frequently described as being illegally added to dietary supplements marketed for weight loss, muscle building/sport performance and sexual performance enhancement. Information regarding regulation and consumption is also presented. Finally, several conventional and advanced analytical techniques used to detect and identify different adulterants in dietary supplements and therefore also in foods, with particular emphasis on plant food supplements, are critically described. This review demonstrates that dietary supplement adulteration is an emerging food safety problem and that an effective control by food regulatory authorities is needed to safeguard consumers.

Rapid on-site detection of ephedrine and its analogues used as adulterants in slimming dietary supplements by TLC-SERS

Ephedrine and its analogues are in the list of prohibited substance in adulteration to botanical dietary supplements (BDS) for their uncontrollable stimulating side effects. However, they were always adulterated illegally in BDS to promote losing weight. In order to avoid detection, various kinds of ephedrine analogues were added rather than ephedrine itself. This has brought about great difficulties in authentication of BDS. In this study, we put forward for the first time a method which combined thin-layer chromatography (TLC) and surface-enhanced Raman scattering (SERS) to directly identify trace adulterant. Ephedrine, pseudoephedrine, methylephedrine, and norephedrine were mixed and used in this method to develop an analytical model. As a result, the four analogues were separated efficiently in TLC analysis, and trace-components and low-background SERS detection was realized. The limit of detection (LOD) of the four analogues was 0.01 mg/mL. Eight common Raman peaks (△υ = 620, 1003, 1030, 1159, 1181, 1205, 1454, 1603 cm(-1)) were extracted experimentally and statistically to characterize the common feature of ephedrine analogues. A TLC-SERS method coupled with common-peak model was adopted to examine nine practical samples, two of which were found to be adulterated with ephedrine analogues. Identification results were then confirmed by UPLC-QTOF/MS analysis. The proposed method was simple, rapid, and accurate and can also be employed to trace adulterant identification even when there are no available reference derivatives on-site or unknown types of ephedrine analogues are adulterated.

Comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats and microarray analysis of drug-metabolizing genes

ETHNOPHARMACOLOGICAL RELEVANCE

Rhein is a pharmacological active component found in Rheum palmatum L. that is the major herb of the San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have investigated the comparative pharmacokinetics of rhein in normal and constipated rats. Microarray analysis was used to explore whether drug-metabolizing genes will be altered after SHXXT treatment.

MATERIALS AND METHODS

The comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats was studied by liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS). Gene expression profiling in drug-metabolizing genes after SHXXT treatment was investigated by microarray analysis and real-time polymerase chain reaction (RT-PCR).

RESULTS

A validated LC-MS/MS method was applied to investigate the comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats. The pharmacokinetic results demonstrate that the loperamide-induced constipation reduced the absorption of rhein. Cmax significantly reduced by 2.5-fold, the AUC decreased by 27.8%; however, the elimination half-life (t1/2) was prolonged by 1.6-fold. Tmax and mean residence time (MRT) were significantly prolonged by 2.8-fold, and 1.7-fold, respectively. The volume of distribution (Vss) increased by 2.2-fold. The data of microarray analysis on gene expression indicate that five drug-metabolizing genes, including Cyp7a1, Cyp2c6, Ces2e, Atp1b1, and Slc7a2 were significantly altered by the SHXXT (0.5 g/kg) treatment.

CONCLUSION

The loperamide-induced constipation reduced the absorption of rhein. Since among the 25,338 genes analyzed, there were five genes significantly altered by SHXXT treatment. Thus, information on minor drug-metabolizing genes altered by SHXXT treatment indicates that SHXXT is relatively safe for clinical application.

Determination of bioactive components in Chinese herbal formulae and pharmacokinetics of rhein in rats by UPLC-MS/MS

Rhein (4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid, cassic acid) is a pharmacological active component found in Rheum palmatum L. the major herb of San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have determined multiple bioactive components in SHXXT and investigated the comparative pharmacokinetics of rhein in rats. A sensitive and specific method combining liquid chromatography with electrospray ionization tandem mass spectrometry has been developed and validated to simultaneously quantify six active compounds in the pharmaceutical herbal product SHXXT to further study their pharmacokinetics in rats. Multiple reaction monitoring (MRM) was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. There were no significant matrix effects in the quantitative analysis and the mean recovery for rhein in rat plasma was 91.6%±3.4%. The pharmacokinetic data of rhein demonstrate that the herbal formulae or the single herbal extract provide significantly higher absorption rate than the pure compound. This phenomenon suggests that the other herbal ingredients of SHXXT and rhubarb extract significantly enhance the absorption of rhein in rats. In conclusion, the herbal formulae (SHXXT) are more efficient than the single herb (rhubarb) or the pure compound (rhein) in rhein absorption.

Direct analysis of samples under ambient condition by high-voltage-assisted laser desorption ionization mass spectrometry in both positive and negative ion mode

RATIONALE

With the rapid development of ambient mass spectrometry, the hybrid laser-based ambient ionization methods which can generate multiply charged ions of large biomolecules and also characterize small molecules with good signal-to-noise in both positive and negative ion modes are of particular interest.

METHODS

An ambient ionization method termed high-voltage-assisted laser desorption ionization (HALDI) is developed, in which a 1064 nm laser is used to desorb various liquid samples from the sample target biased at a high potential without the need for an organic matrix. The pre-charged liquid samples are desorbed by the laser to form small charged droplets which may undergo an electrospray-like ionization process to produce multiply charged ions of large biomolecules.

RESULTS

Various samples including proteins, oligonucleotides (ODNs), drugs, whole milk and chicken eggs have been analyzed by HALDI-MS in both positive and negative ion mode with little or no sample preparation. In addition, HALDI can generate intense signals with better signal-to-noise in negative ion mode than laser desorption spay post-ionization (LDSPI) from the same samples, such as ODNs and some carboxylic-group-containing small drug molecules.

CONCLUSIONS

HALDI-MS can directly analyze a variety of liquid samples including proteins, ODNs, pharmaceuticals and biological fluids in both positive and negative ion mode without the use of an organic matrix. This technique may be further developed into a useful tool for rapid analysis in many different fields such as pharmaceutical, food, and biological sciences.