Retinol (vitamin A) circulates at 1-4 μM concentration and is easily measured in serum. However, retinol is biologically inactive. Its metabolite, retinoic acid (RA), is believed to be responsible for biological effects of vitamin A, and hence the measurement of retinol concentrations is of limited value. A UHPLC-MS/MS method using isotope-labeled internal standards was developed and validated ...

Metabolomics is a promising avenue for biomarker discovery. Although the quality of metabolomic analyses, especially global metabolomics (G-Met) using mass spectrometry (MS), largely depends on the instrumentation, potential bottlenecks still exist at several basic levels in the metabolomics workflow. Therefore, we established a precise protocol initially for the G-Met analyses of human blood p...

Geopropolis is a special type of propolis produced by stingless bees. Several pharmacological properties have been described for different types of geopropolis, but there have been no previous studies of the geopropolis from Melipona mondury. In this study, we investigated the antioxidant, antibacterial, and antiproliferative activities of M. mondury geopropolis, and determined its chemical pro...

With its traditional use in relieving insomnia and anxiety, our previous study has identified onjisaponin B from Radix Polygalae (RP), as a novel autophagic enhancer with potential neuroprotective effects. In current study, we have further identified a novel active fraction from RP, contains 17 major triterpenoid saponins including the onjisaponin B, by the combinational use of cell membrane ch...

The aim of this study was to develop a new, rapid and highly sensitive UHPLC method with UV detection for simultaneous determination of risperidone and four other related substances possibly present in tablets. The active substance, risperidone, is the most frequently used atypical antipsychotic drug for a treatment of schizophrenia, bipolar disease and behavioral disorders in young patients, u...

Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs are ubiquitous in the environment. Some of them are probable carcinogens and some are source markers. This work presents an ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry (UHPLC-APPI-MS/MS) method for simultaneous analysis of 20 PAHs and nine nitro-PAHs. These compounds are separat...

BACKGROUND Tianma-Gouteng-Yin (TGY), which is common Chinese medicine formulation consisting of 11 different herbs and being used in China for the treatment of Parkinson's disease, inflammatory conditions and cardiovascular diseases, was selected for full component analysis. The aim of this study was to quantitatively analyze the chemical profiles of ten commercial TGY samples and one sample pr...

An ultra high-sensitivity method for quantifying fexofenadine concentration in rat plasma samples by multiple injection method (MIM) was developed for a microdose study. In this study, MIM involved continuous injections of multiple samples containing the single compound into a column of the ultra-HPLC (UHPLC) system, and then, temporary trapping of the analyte at the column head. This was follo...

Polygoni Multiflori Radix (PMR) has been commonly used as a tonic in China for centuries. PMR-associated hepatotoxicity has been drawing increasingly more attention in recent years in parallel with its wide utilization. Anthraquinones (AQs) are recognized as the main hepatotoxic components in PMR. However, the exact underlying mechanism of AQs poisoning is still not fully understood. Herein, we...