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Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra‐high performance liquid chromatography–quadrupole/orbitrap high‐resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra‐ and inter‐day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6 and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex. [ABSTRACT FROM AUTHOR]

Ribonucleic acid N6‐methyladenosine methylation plays an important role in a variety of biological processes and diseases. Acetaminophen‐induced hepatotoxicity is one of the major challenges faced by clinicians. To date, the link between N6‐methyladenosine and acetaminophen‐induced hepatotoxicity has not been studied. In this study, a simple ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of five nucleosides (adenosine, uridine, cytidine, guanosine, and N6‐methyladenosine) in messenger ribonucleic acid. After enzymatic digestion of messenger ribonucleic acid, the nucleosides sample was separated on an Acquity UPLC column with gradient elution using methanol and 0.02% formic acid water, and detected by a Qtrap 4500 mass spectrometer with an electrospray ionization mode. The method was validated over the concentration ranges of 4–800 ng/mL for adenosine, uridine, cytidine, and guanosine and 0.1–20 ng/mL for N6‐methyladenosine. It was successfully applied to the determination of N6‐methyladenosine levels in liver messenger ribonucleic acid in an acetaminophen‐induced hepatotoxicity mouse model and a control group. This study offers a method for the determination of nucleoside contents in epigenetic studies and constitutes the first step toward the investigation of ribonucleic acid methylation in acetaminophen‐induced hepatotoxicity, which will facilitate the elucidation of its mechanism. [ABSTRACT FROM AUTHOR]

Ribonucleic acid N 6 -methyladenosine methylation plays an important role in a variety of biological processes and diseases. Acetaminophen-induced hepatotoxicity is one of the major challenges faced by clinicians. To date, the link between N 6 -methyladenosine and acetaminophen-induced hepatotoxicity has not been studied. In this study, a simple ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of five nucleosides (adenosine, uridine, cytidine, guanosine, and N 6 -methyladenosine) in messenger ribonucleic acid. After enzymatic digestion of messenger ribonucleic acid, the nucleosides sample was separated on an Acquity UPLC column with gradient elution using methanol and 0.02% formic acid water, and detected by a Qtrap 4500 mass spectrometer with an electrospray ionization mode. The method was validated over the concentration ranges of 4-800 ng/mL for adenosine, uridine, cytidine, and guanosine and 0.1-20 ng/mL for N 6 -methyladenosine. It was successfully applied to the determination of N 6 -methyladenosine levels in liver messenger ribonucleic acid in an acetaminophen-induced hepatotoxicity mouse model and a control group. This study offers a method for the determination of nucleoside contents in epigenetic studies and constitutes the first step toward the investigation of ribonucleic acid methylation in acetaminophen-induced hepatotoxicity, which will facilitate the elucidation of its mechanism., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)