[Occurrences and dietary exposure analysis for acaricides in the 6th Chinese total diet study].

OBJECTIVE: To study the residue levels of acaricides in Chinese dietary samples and dietary intakes of Chinese residents. METHODS: A total of 288 mixed dietary samples from 24 provinces in the 6 th Chinese total diet study were analyzed for residue levels of acaricides by liquid chromatography-high resolution mass spectrometry. Additionally, based on the dietary consumption of local residents, the dietary intake of acaricides was estimated. RESULTS: Among the tested dietary samples, the detection rates of pyridaben, spirodiclofen and propargite were 11. 8%(34/288), 8. 7%(25/288), and 6. 3%(18/288), respectively. They were mainly detected in vegetable and fruit samples. The average residue level of pyridaben in the vegetable samples was higher than that in other dietary samples with the content of 6. 26 µg/kg. The average residue level of spirodiclofen in the fruits samples was higher than that in other dietary samples with the content of 3. 92 µg/kg. The average residue level of propargite in the vegetable samples was higher than that in other dietary samples with the content of 0. 90 µg/kg. According to the dietary exposure analysis, the average dietary exposure levels of pyridaben, spirodiclofen and propargite in the general population of China were 48. 31, 1. 62 and 2. 25 ng/(kg·d), respectively. According to the dietary contribution rate, the three acaricides were mainly from vegetable samples. CONCLUSION: Although acaricides were detected in varying degrees in the Chinese dietary samples, the general population's health risk caused by the dietary intake in China is at a low level.

Comparative Metabolism Study of Five Protoberberine Alkaloids in Liver Microsomes from Rat, Rhesus Monkey, and Human.

Protoberberine alkaloids including berberine, palmatine, jatrorrhizine, coptisine, and epiberberine are major components in many medicinal plants. They have been widely used for the treatment of cancer, inflammation, diabetes, depression, hypertension, and various infectious areas. However, the metabolism of five protoberberine alkaloids among different species has not been clarified previously. In order to elaborate on the in vitro metabolism of them, a comparative analysis of their metabolic profile in rat, rhesus monkey, and human liver microsomes was carried out using ultrahigh-performance liquid chromatography coupled with a high-resolution linear trap quadrupole-Orbitrap mass spectrometer (UHPLC-electrospray ionization-Orbitrap MS) for the first time. Each metabolite was identified and semiquantified by its accurate mass data and peak area. Fifteen metabolites were characterized based on accurate MS/MS spectra and the proposed MS/MS fragmentation pathways including demethylation, hydroxylation, and methyl reduction. Among them, the content of berberine metabolites in human liver microsomes was similar with those in rhesus monkey liver microsomes, whereas berberine in rat liver microsomes showed no demethylation metabolites and the content of metabolites showed significant differences with that in human liver microsomes. On the contrary, the metabolism of palmatine in rat liver microsomes resembled that in human liver microsomes. The content of jatrorrhizine metabolites presented obvious differences in all species. The HR-ESI-MS/MS fragmentation behavior of protoberberine alkaloids and their metabolic profile in rat, rhesus monkey, and human liver microsomes were investigated for the first time. The results demonstrated that the biotransformation characteristics of protoberberine alkaloids among different species had similarities as well differences that would be beneficial for us to better understand the pharmacological activities of protoberberine alkaloids.

Pharmacokinetic-Pharmacodynamic Analysis on Inflammation Rat Model after Oral Administration of Huang Lian Jie Du Decoction.

Huang-Lian-Jie-Du Decoction (HLJDD) is a classical Traditional Chinese Medicine (TCM) formula with heat-dissipating and detoxifying effects. It is used to treat inflammation-associated diseases. However, no systematic pharmacokinetic (PK) and pharmacodynamic (PD) data concerning the activity of HLJDD under inflammatory conditions is available to date. In the present study, the concentration-time profiles and the hepatic clearance rates (HCR) of 41 major components in rat plasma in response to the oral administration of a clinical dose of HLJDD were investigated by LC-QqQ-MS using a dynamic multiple reaction monitoring (DMRM) method. Additionally, the levels of 7 cytokines (CKs) in the plasma and the body temperature of rats were analyzed. Furthermore, a PK-PD model was established to describe the time course of the hemodynamic and anti-inflammatory effects of HLJDD. As one of the three major active constituents in HLJDD, iridoids were absorbed and eliminated more easily and quickly than alkaloids and flavonoids. Compared with the normal controls, the flavonoids, alkaloids and iridoids in inflamed rats exhibited consistently changing trends of PK behaviors, such as higher bioavailability, slower elimination, delays in reaching the maximum concentration (Tmax) and longer substantivity. The HCR of iridoids was different from that of alkaloids and flavonoids in inflamed rats. Furthermore, excellent pharmacodynamic effects of HLJDD were observed in inflamed rats. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1ß, IL-10, and macrophage inflammatory protein-2 (MIP-2) and body temperature significantly decreased after the administration of HLJDD. Based on PK-PD modeling with the three-phase synchronous characterization of time-concentration-effect, flavonoids exhibited one mechanism of action in the anti-inflammatory process, while iridoids and alkaloids showed another mechanism of action. Taken together, the results demonstrated that HLJDD may restrain inflammation synergistically via its major constituents (alkaloids, flavonoids and iridoids). A correlation between the exposure concentration of different types of compounds and their anti-inflammatory effects in the body was shown. This study provides a comprehensive understanding of the anti-inflammatory activity of HLJDD.

An Approach to Characterizing the Complicated Sequential Metabolism of Salidroside in Rats.

Metabolic study of bioactive compounds that undergo a dynamic and sequential process of metabolism is still a great challenge. Salidroside, one of the most active ingredients of Rhodiola crenulata, can be metabolized in different sites before being absorbed into the systemic blood stream. This study proposed an approach for describing the sequential biotransformation process of salidroside based on comparative analysis. In vitro incubation, in situ closed-loop and in vivo blood sampling were used to determine the relative contribution of each site to the total metabolism of salidroside. The results showed that salidroside was stable in digestive juice, and it was metabolized primarily by the liver and the intestinal flora and to a lesser extent by the gut wall. The sequential metabolism method described in this study could be a general approach to characterizing the metabolic routes in the digestive system for natural products.

[Chemical studieson hydrophilic constituents of toad skin].

Fifteen compounds were isolated from the toad skin by a combination of various chromatographic methods including macroporous resin, silica gel, ODS and semi-preparative HPLC. Their structures were identified as 4,5-dimethyl-1,3,4,5-tetrahydropyrrolo[4,3,2-de]quinolin-6-ol(1), serotonin(2), N-methyl serotonin(3), O-methyl bufotenine(4), 1,2,3,4-tetrahydro-6-hydroxy-ß-carboline(5), O-methylserotonin(6), glycinebetaine(7), caffeine(8), bufotenine(9), shepherdine(10), tryptophan(11), (5-hydroxy-1H-indol-3-yl)acetic acid(12), 5-hydroxy tryptophol(13), 2-methyl-6-hydroxy-1,2,3,4-tetrahydro-ß-carboline(14), bufothionine(15). Among them, compound 1 was a new compound,compound 5 was a new natural product. Compounds 4-8 and 10-14 were separated from toad skin for the first time.

Comparative metabolism of four limonoids in human liver microsomes using ultra-high-performance liquid chromatography coupled with high-resolution LTQ-Orbitrap mass spectrometry.

RATIONALE: Limonoids, characterized by a triterpenoid skeleton with a furan ring, are unique secondary metabolites widely distributed in the families of Rutaceae, particularly in Citrus species and Meliaceae. Studies on health benefits have demonstrated that limonoids have a range of biological activities. Dietary intake of citrus limonoids may provide a protective effect against the onset of various cancers and other xenobiotic related diseases. However, few studies about the metabolic profiles of limonoids have been carried out. METHODS: The objectives of this study were to investigate the metabolic profiles of four limonoids (limonin, obacunone, nominin and gedunin) in human liver microsomes (HLMs) using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC/HRMS) and to identify the cytochrome P450 (CYP) enzymes involved in the formation of their metabolites by recombinant human CYP enzymes. RESULTS: Based on the accurate HR-MS/MS spectra and the proposed MS/MS fragmentation pathways, four metabolites of limonin (M1-1, M1-2, M1-3 and M1-4), eight metabolites ofobacunone (M2-1, M2-2, M2-3, M2-4, M2-5, M2-6, M2-7 and M2-8), six metabolites of nominin (M3-1, M3-2, M3-3, M3-4, M3-5 and M3-6) and three metabolites of gedunin (M4-1, M4-2 and M4-3) in HLMs were tentatively identified and the involved CYPs were investigated. CONCLUSIONS: The results demonstrated that reduction at C-7 and C-16, hydroxylation and reaction of glycine with reduction limonoids were the major metabolic pathways of limonoids in HLMs. Among them, glycination with reduction was the unique metabolic process of limonoids observed for the first time. CYP2D6 and CYP3A4 played an important role in the isomerization and glycination of limonoids in HLMs, whereas other CYP isoforms were considerably less active. The results might help to understand the metabolic process of limonoids in vitro such as the unidentified metabolites of limonin glucoside observed in the medium of microbes and the biotransformation of limonin in juices. Moreover, it would be beneficial for us to further study the pharmacokinetic behavior of limonoids in vivo systematically.

Metabolic profiling analysis of berberine, palmatine, jatrorrhizine, coptisine and epiberberine in zebrafish by ultra-high performance liquid chromatography coupled with LTQ Orbitrap mass spectrometer.

1. Zebrafish has been used in metabolic study of drugs as a powerful tool in recent years. In this study, we make a feasible metabolism investigation of five protoberberine alkaloids (PBAs) applied in zebrafish model for the first time, including berberine (BBR), palmatine (PAL), jatrorrhizine (JAT), coptisine (COP) and epiberberine (EBBR). 2. After exposure for 24 hours, 19 metabolites were identified by LTQ Orbitrap mass spectrometer, including 9 phase I metabolites and 10 phase II metabolites. Demethylation, hydroxylation, sulfation and glucuronidation were the major metabolic transformation of PBAs in zebrafish, which were similar to mammals. Compared with reported literatures, BBR and JAT showed high consistency between human and zebrafish in metabolic pathways. 3. To our knowledge, this is the first time to study in vivo metabolism of COP, which provides useful information to other researchers. 4. This study indicated that zebrafish model is feasible and reasonable to predict the metabolism of PBAs. It showed great potential for developing a novel and rapid method for predicting the metabolism of trace compounds of botanical drugs, with the advantages of lower cost, higher performance and easier set up.