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Abstract: As biomarkers, endogenous neurotransmitters play critical roles in the process of neuropsychiatric diseases, and neurotransmitter levels in different brain regions can contribute to neurological disease diagnosis and treatment. Due to the lack of a blank matrix for endogenous neurotransmitters, surrogate‐matrix and surrogate‐analyte approaches have been used for the determination of neurotransmitters to solve this problem. In this study, we capitalised on the high accuracy, precision, and throughput of UHPLC‐MS/MS and developed new methods based on the two approaches. Both approaches satisfied FDA and EMA validation criterias after an appropriate parallelism assessment, and they were used to further quantify the three endogenous neurotransmitters, including dopamine (DA), serotonin (5‐HT) and γ‐aminobutyric acid (GABA) in rat brain four regions (cortex, striatum, hypothalamus and hippocampus) which represent the catecholamines, indolamines, and amino acids, respectively. Comparison of the results in the same rats (n = 10) showed there was no significant difference in DA, 5‐HT, or GABA levels between the two approaches (P > 0.05). The concentrations of DA and GABA were highest in striatum and hypothalamus, respectively, and the levels of 5‐HT were paralleled in striatum and hippocampus almost 2‐fold higher than other regions. This is the first study to compare these two approaches in the determination of endogenous neurotransmitter content in the rat brain, and the surrogate‐matrix approach proved to be simple, rapid, and reliable, considering cost, matrix similarity, and practicality. [ABSTRACT FROM AUTHOR]

Objective: The influence of processing methods on chemical constituents in Radix Paeoniae Alba was observed., Method: A HPLC method was used for analyzing the changes of eight major constituents, namely gallic acid, paeoniflorin sulfonate, catechin, paeoniflorin sulfonate, albiflorin, paeoniflorin, benzoic acid, pentagalloylglucose and benzoylpaeoniflorin, with the three processing procedures of decorticating, boiling and fumigating by burning of sulphur. Analysis was performed using a Zorbax SB-C18 column (4.6 mm x 250 mm, 5 microm) with the mixture of acetonitrile (A) and 0.015% phosphoric acid solution as mobile phase in gradient mode. The detection wavelength was set at 230 nm and the column temperature was at 30 degrees C., Result: Except for gallic acid and pentagalloylglucose, the other constituents decreased during procedure of decorticating and boiling. Fumigating by burning of sulphur would produce a new compound, paeoniflorin sulfonate, which was a byproduct from the reaction of paeoniflorin with SO2., Conclusion: The significant changes were produced in chemical constituents of Radix Paeoniae Alba during three processing procedures. Therefore, the processing of Radix Paeoniae Alba should be strictly controlled and standardized.

Aim: To establish the method of HPLC-fingerprint analysis for the quality control of Dalbergia odorifera and identify its main constituents by HPLC-MS., Methods: The 37 hatches of samples were analyzed on a Phenomenex Luna C18 column with a gradient of acetonitrile and 0.3% aqueous acetic acid at a flow rate of 1.0 mL x min(-1) and detected at 275 nm. Furthermore, the typical samples were detected by HPLC-DAD-MS under negative ion mode., Results: 37 batches of D. odorifera samples were classified into three types based on the results of similarity analysis. According to the comparison of the tR, MS data and UV maximum absorbance (gamma(max)) values with the standards, 10, 7 and 2 phenolic components were identified in three types of D. odorifera extracts, separately., Conclusion: The method is repeatable and reliable, and it is capable of effectively controlling the quality of D. odorifera.