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Abstract (+)-usnic acid (UA) is an active natural phenolic acid ingredient originating from Chinese traditional Tibetan herb. Usnea acid is expected to become a new agent for anticancer and remarkable antitumor. To reveal its metabolic profile, metabolites identification of UA in vivo was studied using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS) in this present study. The chromatographic separation was performed on a C 18 column with a mobile phase consisted of methanol and water with a flow rate of 0.4 ml/min. The mass spectral analysis conducted in a negative electrospray ionization mode combined with information-dependent acquirement technology (IDA) was used to trace all the potential UA metabolites. Several sensitive and specific multiple data-mining techniques especially key product ions (KPIs) filter were applied to hunt and identify metabolites rapidly. As a result, a total of 36 metabolites were detected after oral administration of UA, including 33, 8 and 16 in rat urine, plasma and bile, respectively. These results showed that the probable metabolite pathways of UA were oxidation, reduction, dihydroxylation, glycine conjugation, glucuronide conjugation, N -acetylcysteine conjugation and methylation. It is the first time to elucidate the profile of UA in vivo. These results not only provided the basis of UA pharmacological properties, but also gave the guidance in clinical medication. Moreover, the analysis strategy and methodology proposed in this paper could be widely used in characterization of other phenolic acids metabolites. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract: Arctiin, an important lignan compound in Fructus Arctii, has been reported to possess various kinds of bioactivities. Previous studies on the pharmacokinetic of arctiin after oral administration showed that it had a rapid absorption phase followed by a sharp but lasting disappearance. To gain deep insight into the action mechanism of arctiin, the excretion and metabolism of arctiin in vivo should be further studied. In this paper, three metabolites were isolated and identified in rat feces as (−)-enterolactone (M-1), (−)-arctigenin (M-2) and [(2R,3R)-2-(3′-hydroxybenzyl)-3-(3″,4″-dimethoxybenzyl)-butyrolactone] (M-3). Based on the structures of three metabolites, possible metabolic pathways of arctiin in rats are proposed. At the same time, the cumulative excretion rate of arctiin and its metabolites in rat urine and feces were determined, indicating that arctiin was excreted 19.84% in urine and 1.80% in feces, respectively, enterolactone, the most main metabolite, was excreted 35.80% in feces. These results provide very important information for understanding the metabolism and excretion of arctiin in vivo and speculating its action mechanism, they can provide useful information and reference for further metabolic investigations on arctiin in humans. [Copyright &y& Elsevier]

Abstract: Ethnopharmacological relevance: Traditional Chinese medicine (TCM) has been used in clinical practice for several thousand years. TCM has played an indispensable role in the prevention and treatment of diseases, especially the complicated and chronic ones. Pharmacokinetic study on active constituents in herbal preparations is a good way for us to explain and predict a variety of events related to the efficacy and toxicity of TCM. Aim of the study: A selective and sensitive HPLC–MS/MS method was first developed and validated for the determination of luteolin, kaempferol, apigenin, quercetol, and isorhamnetin in rat plasma. Materials and methods: The LC system consisted of an Agilent Technologies Series 1200 system (Agilent, USA) equipped with an automatic degasser, a quaternary pump, and an autosampler. Chromatographic separations were performed on a Waters SunFire™ C18 column (150mm×4.6mm, 5μm), and the column temperature was maintained at 25°C and the sample injection volume was 20μL. The current LC–MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability. Results: The validated method was successfully applied to monitoring the concentrations and pharmacokinetic studies of five flavone compounds in rat plasma after a single oral administration of Verbena officinalis L. extract with a dosage of 8.0mL/kg. The time to reach the maximum plasma concentration (T max1) was 0.48±2.14h for luteolin, 0.25±0.13h for kaempferol, 0.97±1.08h for apigenin, 1.04±4.25h for quercetol and 0.25±0.16h for isorhamnetin, and the maximum plasma concentration (T max2) was 3.97±1.48h, 4.05±0.46h, 4.33±0.58h, 2.99±0.48h and 4.02±0.34h. The elimination half-time (t 1/2) of luteolin, kaempferol, apigenin, quercetol and isorhamnetin was 4.02±0.81, 7.65±0.71, 3.30±0.83, 4.55±0.49 and 5.56±1.32h, respectively. Conclusions: This paper described a simple, sensitive and validated LC–MS/MS method for simultaneous determination of luteolin, kaempferol, apigenin, quercetol and isorhamnetin in rat plasma after oral administration of V. officinalis L. extract, and investigated on their pharmacokinetic studies as well, with a short run time of 5min. [Copyright &y& Elsevier]

Abstract: In this paper, microdialysis combined with ultra performance liquid chromatography/mass spectrometry (UPLC-MS) was applied for the determination of ligustilide in freely moving rats'' brain. The extracellular unbound ligustilide could be detected in rat brain within the first time interval (0–20min) after nasal administration but not after oral administration. This result showed that ligustilide could quickly enter the brain after nasal administration; which implied that ligustilide may have a rapid onset of action. This work demonstrated the potential application of microdialysis combined with UPLC-MS in pharmacokinetic studies. Furthermore, the advantage that fewer animals used in the microdialysis experiment was confirmed. [Copyright &y& Elsevier]