UHPLC-QqQ-MS/MS method development and validation with statistical analysis: Determination of raspberry ketone metabolites in mice plasma and brain

LC-MS/MS method for quantification of raspberry ketone in rat plasma: application to preclinical pharmacokinetic studies

Background: Raspberry ketone (RK), derived from red raspberry fruit (Rubus idaeus, family Rosaceae), is a reported potent antiobesity agent. This study aims to investigate method development, validation, and in vitro and in vivo pharmacokinetics in rats. Materials & methods: LC-MS/MS was used to conduct method development, validation, stability, and oral PK samples of RK in plasma analyses. Results: RK was highly soluble in Tris buffer and stable in gastrointestinal fluids as well as plasma. Rat liver microsomal stability of RK in phase I and II studies was 84.96 ± 2.39 and 69.98 ± 8.69%, respectively, after 60 min. Intestinal permeability was 4.39 ± 1.37 × 10^-5 cm/s. Maximal concentration was 1591.02 ± 64.76 ng/ml, which was achieved after 1 h (time to maximal concentration), and absolute oral bioavailability was 86.28%. Conclusion: Pharmacokinetic data serve as a keystone for preclinical and clinical adjuvant therapy.

Method development and validation for analysis of phenolic compounds in fatty complex matrices using enhanced matrix removal (EMR) lipid cleanup and UHPLC-QqQ-MS/MS

Reliable analysis of phenolic compounds in fatty matrices is a challenging task. In this work, a robust analytical method was developed and validated for 55 phenolic compounds employing QuEChERS (quick, efficient, cheap, easy, rugged and safe) and Enhanced Matrix Removal (EMR)-lipid cleanup in 96-well plates for sample preparation, coupled with ultra-high performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS). Seven high-fat matrices of pork brain, belly and liver; horse serum, beef, salmon and avocado were explored for method validation and led to promising stepwise recoveries of extraction, clean-up, drying-reconstitution of most analytes ranging from 75% to 113%, and with an accuracy of 78%∼117%, except for six catechin-analogues. The matrix removal efficiency of EMR was determined using UHPLC-quadruple time of flight (QTOF)-MS, and results indicated that 56%∼77% of co-extractives were removed. This method would be readily extended to wide range of applications demanding high-throughput and sensitive analysis of phenolic compounds in fatty samples.

Development and Optimization of an HPLC-PDA Method for the Determination of Major Cannabinoids in Hemp (Cannabis sativa L.) Essential Oil Obtained by Hydrodistillation

The use of hemp (Cannabis sativa L.) essential oil (EO) has shown a significant increase in interest and use during recent years. In this work, a new and simple reversed-phase HPLC with photodiode-array (PDA) detector method has been developed and optimized for the detection and quantification of cannabidiolic acid (CBDA), cannabidiol (CBD), cannabinol (CBN), Δ9-tetrahydrocannabinol (Δ9-THC), and Δ9-tetrahydrocannabinolic acid (THCA). The cannabinoids were extracted from the EO by partition with n-hexane and water, followed by sonication, evaporation to dryness under nitrogen, and reconstitution with methanol:chloroform (9:1, v/v) before HPLC-PDA analysis. The method shows good selectivity and robustness, linearity in the range 0.5–100 mg L−1 with R2 higher than 0.999 for all cannabinoids analyzed, LOD of 0.11–0.16 mg L−1, and LOQ of 0.35–0.48 mg L−1. The recovery was between 78 and 100% and the intra-day and intermediate precision, expressed as relative standard deviation (RSD), was < 4% and 4–10%, respectively.

Recent Analytical Approaches for the Study of Bioavailability and Metabolism of Bioactive Phenolic Compounds

The study of the bioavailability of bioactive compounds is a fundamental step for the development of applications based on them, such as nutraceuticals, functional foods or cosmeceuticals. It is well-known that these compounds can undergo metabolic reactions before reaching therapeutic targets, which may also affect their bioactivity and possible applications. All recent studies that have focused on bioavailability and metabolism of phenolic and terpenoid compounds have been developed because of the advances in analytical chemistry and metabolomics approaches. The purpose of this review is to show the role of analytical chemistry and metabolomics in this field of knowledge. In this context, the different steps of the analytical chemistry workflow (design study, sample treatment, analytical techniques and data processing) applied in bioavailability and metabolism in vivo studies are detailed, as well as the most relevant results obtained from them.

Development of a highly efficient in-tube solid-phase microextraction system coupled with UHPLC-MS/MS for analyzing trace hydroxyl polycyclic aromatic hydrocarbons in biological samples

Hydroxyl polycyclic aromatic hydrocarbons are considered active mutagenic and carcinogenic substances and are found in extremely low levels (ng/g) in biological samples. As a result, their determination in urine and blood samples is challenging, and a sensitive and effective method for the analysis of trace hydroxyl polycyclic aromatic hydrocarbons in complex biological matrices is required. In this work, a novel macroporous in-tube solid-phase microextraction monolith was prepared via a thiol-yne click reaction, and a highly efficient analytical method based on in-tube solid-phase microextraction coupled with UHPLC-MS/MS was developed to determine hydroxyl polycyclic aromatic hydrocarbons with low detection limits of 0.137-11.0 ng/L in complex biological samples. Four hydroxyl polycyclic aromatic hydrocarbons, namely, 2-hydroxyanthraquinone, 1-hydroxypyrene, 1,8-dihydroxyanthraquinone, and 6-hydroxychrysene, were determined in the urine samples of smokers, non-smokers, and whole blood samples of mice. Satisfactory recoveries were achieved in the range of 83.1-113% with relative standard deviations of 3.2-9.7%. It was found that implementation of the macroporous monolith gave a highly efficient approach for enriching trace hydroxyl polycyclic aromatic hydrocarbons in biological samples.

Development and validation of a micro-QuEChERS method with high-throughput enhanced matrix removal followed with UHPLC-QqQ-MS/MS for analysis of raspberry ketone-related phenolic compounds in adipose tissues

Raspberry ketone (RK) is a major flavor compound in red raspberries, and it has been marketed as a popular weight-loss dietary supplement with high potential in accumulating in fatty tissues. However, challenges in extracting and characterizing RK and its associated phenolic compounds in fatty tissues persist due to the complex matrix effect. In this work, we reported a high-throughput sample preparation method for RK and 25 related phenolic compounds in white adipose tissues using an improved micro-scale QuEChERS (quick, efficient, cheap, easy, rugged and safe) approach with enhanced matrix removal (EMR)-lipid cleanup in 96-well plates, followed by UHPLC-QqQ-MS/MS analysis. The absolute recovery was 73-105% at the extraction step, and achieved 71-96% at the EMR cleanup step. The EMR cleanup removed around 66% of total lipids in the acetonitrile extract as profiled by UHPLC-QTOF-MS/MS. The innovative introduction of a reversed-phase C18 sorbent into the extract significantly improved the analytes' recovery during SpeedVac drying. The final accuracy achieved 80-120% for most analytes. Overall, this newly developed and validated method could serve as a powerful tool for analyzing RK and related phenolic compounds in fatty tissues.

Quality control of dietary supplements: An economic green spectrofluorimetric assay of Raspberry ketone and its application to weight variation testing

Although Dietary supplements are readily accessible and extensively used worldwide, they are inadequately regulated and consumers are victims of manufacturers' fraud. Thus, quality regulations are required to ensure safety of products available to the public. We propose the first native spectrofluorimetric quality control assay of raspberry ketone, a popular dietary supplement ingredient for weight loss. This work relies on the constant wavelength synchronous scan of the Raspberry Ketone native fluorescence, overcoming the demerits of conventional excitation/ emission spectra. For the best measurement conditions, several parameters were optimized including Δλ value, diluting solvent, medium pH and the effect of surfactants/ macromolecules. In aqueous medium (Δλ = 110 nm), a linear relationship exists between synchronous fluorescence intensity at peak maximum 405.6 nm and solution concentration in the range 300-1500 ng/mL. Method sensitivity was recorded with LOD and LOQ values 60.63 and 183.72 ng/mL; respectively. Validation was done in accordance to International Conference on Harmonization (ICH) guidelines. This simple procedure was successfully applied to the analysis of Raspberry Ketone in commercially available dietary supplement capsules with average recovery 98.67% ± 1.74 and further extended to weight variation testing following the official United States Pharmacopeial (USP) guidelines. Finally, green assessment was done using the ''Analytical Eco-scale'' tool. The total score was 89/100 points revealing excellent greenness of our proposal. Our proposal is simple, eco-friendly and cheap. It can be conveniently adopted for routine quality control practices especially in developing countries.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based assay for simultaneous quantification of aldosterone, renin activity, and angiotensin II in human plasma

Accurate quantification of plasma aldosterone (ALD) and renin activity (PRA)is critical for the diagnosis of primary aldosteronism (PA). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is considered the "gold standard" method for the determination of ALDand PRA. The aim of this study is to develop a new LC-MRM/MS assay for quantifying plasma ALD, PRA, and angiotensin II (Ang II) simultaneously and validate its effectiveness. To be more specific, plasmasamples were prepared by solid-phase extraction and separated in an ultra-performance reversed-phase column. MS detection was performed via a triple quadrupole mass spectrometer containing both positive and negative ion monitoring modes. The developed assay was then validated according to the standard guidelines and the influence of sample incubation on ALD and Ang II concentration was evaluated. In addition, the variation of endogenous Ang I was explored. The proposed LC-MRM/MS method was compared another LC-MS/MS method, which detects ALD, Ang I, and Ang II separately. Analyteswere separated and quantified within 5 min. The assay wasvalidated to be linear up to 5000 pg/ml for ALD and Ang II and 33.3 ng/ml/h for PRA.The lower limit of quantification (LLOQ) was 15 pg/ml, 15 pg/ml, and 0.1 ng/ml/hfor ALD, Ang II, and PRArespectively. Specificity, precision, accuracy, and stability were tested to meet the requirements of the guidelines. Significant changes were not found in ALD and Ang II concentrations over the 3 h-incubation. In addition, it was demonstratedthat the resultof PRA was not stronglyinfluenced by the endogenous Ang I. Comparison with another LC-MS/MS method was performed using the same apparatusand the proposed method was proved to be in good coincidence with the correlation coefficients rangingfrom 0.955to0.996. A sensitive and reliable method for simultaneousquantification of ALD, PRA, and Ang II has been developed and this study will significantly promote laboratory workflow efficiency and throughput.

1-{(E)-[4-(4-Hy-droxy-phen-yl)butan-2-yl-idene]amino}-3-phenyl-thio-urea: crystal structure, Hirshfeld surface analysis and computational study

The title thio-urea derivative, C17H19N3OS, adopts a U-shaped conformation with the dihedral angle between the terminal aromatic rings being 73.64 (5)°. The major twist in the mol-ecule occurs about the ethane bond with the Ci-Ce-Ce-Cb torsion angle being -78.12 (18)°; i = imine, e = ethane and b = benzene. The configuration about the imine bond is E, the N-bound H atoms lie on opposite sides of the mol-ecule and an intra-molecular amine-N-H⋯N(imine) hydrogen bond is evident. In the mol-ecular packing, hydroxyl-O-H⋯S(thione) and amine-N-H⋯O hydrogen bonding feature within a linear, supra-molecular chain. The chains are connected into a layer in the ab plane by a combination of methyl-ene-C-H⋯S(thione), methyl-ene-C-H⋯O(hydrox-yl), methyl-C-H⋯π(phen-yl) and phenyl-C-H⋯π(hy-droxy-benzene) inter-actions. The layers stack without directional inter-actions between them. The analysis of the calculated Hirshfeld surface highlights the presence of weak methyl-C-H⋯O(hydrox-yl) and H⋯H inter-actions in the inter-layer region. Computational chemistry indicates that dispersion energy is the major contributor to the overall stabilization of the mol-ecular packing.

Pharmacological Exploration of Phenolic Compound: Raspberry Ketone-Update 2020

Raspberry ketone (RK) is an aromatic phenolic compound naturally occurring in red raspberries, kiwifruit, peaches, and apples and reported for its potential therapeutic and nutraceutical properties. Studies in cells and rodents have suggested an important role for RK in hepatic/cardio/gastric protection and as an anti-hyperlipidemic, anti-obesity, depigmentation, and sexual maturation agent. Raspberry ketone-mediated activation of peroxisome proliferator-activated receptor-α (PPAR-α) stands out as one of its main modes of action. Although rodent studies have demonstrated the efficacious effects of RK, its mechanism remains largely unknown. In spite of a lack of reliable human research, RK is marketed as a health supplement, at very high doses. In this review, we provide a compilation of scientific research that has been conducted so far, assessing the therapeutic properties of RK in several disease conditions as well as inspiring future research before RK can be considered safe and efficacious with limited side effects as an alternative to modern medicines in the treatment of major lifestyle-based diseases.

A high-resolution MS/MS based strategy to improve xenobiotic metabolites analysis by metabolic pathway extension searching combined with parallel reaction monitoring: Flavonoid metabolism in wound site as a case

For the analysis of xenobiotic metabolism, metabolites are commonly qualified by high-resolution mass spectrometry such as orbitrap or time-of-flight mass spectrometers, and quantified by triple-quadrupole (QQQ) mass spectrometer based multiple reaction monitoring. While this workflow shows drawback in the difficulty for instrumental parameters transfer, and QQQ provides less specificity. In this work, we constructed a high-resolution MS/MS (HR-MS/MS) based strategy to improve the discovery and quantification of unknown xenobiotic metabolites by metabolic pathway extension (MPE) searching combined with parallel reaction monitoring (PRM). Taking the flavonoid metabolism in diabetes wound S9 incubates as a test case. Firstly, MPE approach was used to screen all potential metabolites. In this step, an m/z value library of all theoretic flavonoid metabolites were constructed based on predefined flavonoid structures through 21 common xenobiotic metabolic reactions, and this library was matched with all features extracted from raw data (MS1 scan) of flavonoid-S9 co-incubate, then the matched features were exported into target list for MS2 fragmentation for structure validation. Secondly, the metabolites were relatively quantified by PRM mode based on their characteristic product ions. As a result, 131 metabolites of 9 different kinds of flavonoids in the skin and muscle were identified. To our best knowledge, this is the first report on the metabolism of flavonoids in the skin or muscle tissue. The results also validated the proposed HR-MS/MS-based strategy provided high specificity throughout both discovery and quantitation process of unknown xenobiotic metabolites without need of instrumental parameter transfer.

Rapid screening of glycoalkaloids in Solanum scabrum and S. nigrum berries using ultra-high-performance liquid chromatography with pathway-specified in-source fragmentation tandem mass spectrometry

RATIONALE

The safe consumption of Solanum scabrum and S. nigrum berries (SNBs) depends on a reliable and rapid chemical screen for the testing of the fruit and/or final food and industrial products for the presence and level of toxic glycoalkaloids. Such a rapid and sensitive screen could also be used by those involved in food safety and forensics, industry, research labs and those in agriculture production, breeding and food processing. Significant variation in the content and composition of glycoalkaloids across SNBs has been reported. To facilitate high-throughput targeted analysis, this work overcame the slow scan speed of a traditional triple quadruple mass spectrometry (QqQ) method by development of a pseudo-MS³ method.

METHODS

In-source fragmentation functioned as a pseudo-MS or pseudo-hydrolysis to trim down the structurally diverse and complex glycosides into five types of aglycone ions, which were then analyzed using multiple reaction monitoring (MRM). Characteristic product ions were selected based on the aglycone skeleton and substitution pattern and associated fragmentation pathway.

RESULTS

A compact method with only 15 MRM transitions were developed for high-throughput screening of very diverse glycoalkaloids. Glycosides of the same aglycone type were readily identified in the same transition window without the need for mass spectra interpretation. Validated using solamargine, the sole available standard, the accuracy was 99.7-101.3%, the intra- and inter-day precision were, respectively, 2.5-5.0% and 8.0-9.2%, and the lower limit of detection and quantification were, respectively, 3.1 and 10.2 ng/mL (with 1 μL injection volume).

CONCLUSIONS

The peudo-MS³ method allowed for high-throughput targeted analysis with compact MRM transitions to address a large number of glycoalkaloids with diverse structures. This method could serve to meet the most heavy-duty demand for rapid inspection of glycoalkaloids in SNBs. This method can be adopted and used by those involved in food safety and forensics, in developing food and industrial products and in genetics and breeding.