Development and validation of an LC-MS/MS method for the determination of DPHB in rat plasma and its application in pharmacokinetic studies.

The aim of the present study was to develop a rapid, specific and sensitive LC-MS/MS method for the determination of DPHB [7-(4″-hydroxy-3″-methoxyphenyl)-1-phenyl-4-hepten-3-one] in rat plasma using yakuchinone A as an internal standard (IS). n-Hexane was used for the extraction of DPHB from rat plasma. Chromatographic separation of DPHB was achieved using a Kinetex XB-C18 column (2.10 × 50 mm, 2.6 µm) at 40°C. The mobile phase consisted of water (containing 0.1‰ formic acid, A) and acetonitrile (containing 0.1‰ formic acid, B) under a gradient elution at a flow rate of 0.3 mL min-1 . Positive electrospray ionization and multiple reaction monitoring mode were used for detection. The selected precursor ion to product ion pairs, m/z 311.3 → 137.0 for DPHB and m/z 313.1 → 137.0 for yakuchinone A, were monitored. Good linearity was observed over the concentration range from 2 to 2000 ng mL-1 (r = 0.9969). The recovery efficiency of DPHB from rat plasma was 54.8-69.7%, while the matrix effect ranged from 99.7 to 113%. Intra- and inter-day precision and accuracy values were within ±15% at three different quality control concentration levels. This validated method was successfully applied to pharmacokinetic studies in rats after a single p.o. or i.v. dose of DPHB solution. The route of administration significantly influenced systemic exposure to DPHB, and low bioavailability of DPHB was observed. The method developed here will be further improved and used in future pharmacokinetic studies.

Different accumulation profiles of multiple components between pericarp and seed of Alpinia oxyphylla capsular fruit as determined by UFLC-MS/MS.

Plant secondary metabolites are known to not only play a key role in the adaptation of plants to their environment, but also represent an important source of active pharmaceuticals. Alpinia oxyphylla capsular fruits, made up of seeds and pericarps, are commonly used in traditional East Asian medicines. In clinical utilization of these capsular fruits, inconsistent processing approaches (i.e., hulling pericarps or not) are employed, with the potential of leading to differential pharmacological effects. Therefore, an important question arises whether the content levels of pharmacologically active chemicals between the seeds and pericarps of A. oxyphylla are comparable. Nine secondary metabolites present in A. oxyphylla capsular fruits, including flavonoids (e.g., tectochrysin, izalpinin, chrysin, apigenin-4',7-dimethylether and kaempferide), diarylheptanoids (e.g., yakuchinone A and B and oxyphyllacinol) and sesquiterpenes (e.g., nootkatone), were regarded as representative constituents with putative pharmacological activities. This work aimed to investigate the abundance of the nine constituents in the seeds and pericarps of A. oxyphylla. Thirteen batches of A. oxyphylla capsular fruits were gathered from different production regions. Accordingly, an ultra-fast high performance liquid chromatography/quadrupole tandem mass spectrometry (UFLC-MS/MS) method was developed and validated. We found that: (1) the nine secondary metabolites were differentially concentrated in seeds and fruit capsules; (2) nootkatone is predominantly distributed in the seeds; in contrast, the flavonoids and diarylheptanoids are mainly deposited in the capsules; and (3) the content levels of the nine secondary metabolites occurring in the capsules varied greatly among different production regions, although the nootkatone levels in the seeds were comparable among production regions. These results are helpful to evaluating and elucidating pharmacological activities of A. oxyphylla capsular fruits. Additionally, it may be of interest to elucidate the mechanisms involved in the distinct accumulation profiles of these secondary metabolites between seeds and pericarps.

[HPLC fingerprint of Callicarpa nudiflora].

OBJECTIVE: To establish HPLC fingerprint method for the quality evaluation and discrimination of Callicarpa nudiflora. METHODS: The chromatographic fingerprint of the 12 samples was determined by injecting 20 microL of the sample solution each time on a reversed phase Agilent TC-C18 column with the gradient elution solvent system composed of 0.30% HAc solution and acetonitrile. The flow rate was 1.0 mL/min, the column temperature was maintained at 30 degrees C and the detection wavelength was set at 254 nm. RESULTS: The HPLC fingerprint of Callicarpa nudiflora was set up,which included 20 common peaks, and the similarities of 12 samples were basically more than 0.90. Also,3 components were identified. CONCLUSION: The method is accurate, repeatable, reliable and can fully reflect the chemical composition information, which can be used for the discrimination and the quality control of Callicarpa nudiflora.

Effect of Alpinia officinarum Hance alcohol extracts on primary dysmenorrheal.

OBJECTIVE: To study the effect of Alpinia officinarum Hance (A. officinarum) 80% alcohol extract on the primary dysmenorrhea. METHODS: A. officinarum 80% alcohol extract were enriched by macroporous adsorption resins. Female mice of primary dysmenorrhea model were established by oxytocin induction; the effects of A. officinarum 80% alcohol extract on primary dysmenorrhea were observed by body twist method; and the homogenate level of prostaglandin F2α (PGF2α), prostaglandin E2 (PGE2) and Ca(2+) in the uterus were observed in oxytocin-induced female mice. RESULTS: The writhing frequency of primary dysmenorrhea mice was significantly decreased after treatment of A. officinarum 80% alcohol extract and the level of PGF2α, PGE2 and Ca(2+) in mice uterus was significantly decreased (P < 0.05, P < 0.01) in groups of mice treated with middle and high dosage of A. officinarum 80% alcohol extract compared with that of model group. CONCLUSIONS: These findings suggest that A. Officinarum 80% alcohol extract can significantly relieve primary dysmenorrhea.

Differential systemic exposure to galangin after oral and intravenous administration to rats.

BACKGROUND: Galangin (3,5,7-trihydroxyflavone) is present in high concentrations in herbal medicine such as Alpinia officinarum Hance. Galangin shows multifaceted in vitro and in vivo biological activities. The number and position of hydroxyl groups in this molecule play an important role in these biological activities. However, these hydroxyl groups undergo glucuronidation and sulfation in in vitro assay system. However, the systemic exposure to galangin after dosing in animals and/or humans remains largely unknown. Thus it is not clear whether the galangin exists in the body at concentrations high enough for the biological effects. Furthermore, the metabolite identification and the corresponding plasma pharmacokinetics need to be characterized. RESULTS: Two LC-MS/MS methods were developed and validated and successfully applied to analyze the parent drug molecules and aglycones liberated from plasma samples via ß-glucuronidase hydrolysis. Our major findings were as follows: (1) The routes of administration showed significant influences on the systemic exposure of galangin and its metabolites. (2) Galangin was preferentially glucuronidated after p.o. dosing but sulfated after i.v. medication. (3) Kaempferol conjugates were detected demonstrating that oxidation reaction occurred; however, both glucuronidation and sulfation were more efficient. (4) Oral bioavailability of free parent galangin was very low. CONCLUSIONS: Systemic exposure to galangin and its metabolites was different in rat plasma between oral and intravenous administration. Further research is needed to characterize the structures of galangin conjugates and to evaluate the biological activities of these metabolites. Graphical abstractGalangin was preferentially glucuronidated after p.o. dosing but sulfated after i.v. medication.

[Expression of Streptococcus mutans surface protein PAcP and cholera toxin B subunit fusion gene in transgenic tomato].

PURPOSE: To detect the protein expression level of foreign fused gene in the first generation of genetically modified tomatoes transformed with fused gene of antigen epitope PacP in surface protein of Streptococcus mutans and cholera toxin B subunit. METHODS: The total DNA in tomatoes was extracted and PCR was applied to screen the first generation of transgenic tomatoes carrying Streptococcus mutans surface protein coding PAcP with cholera toxin B subunit fusion gene. Total proteins were extracted and quantitatively tested with BAC kit. Foreign fused protein expression level was analysed by Western blotting and ELISA. RESULTS: Ten DNA samples with the full length of 1.6 kb foreign fused DNA fragment was detected by PCR among all 18 samples. The crude protein in the transgenic tomato fruit tissue was 3.93 mg/mL. Compared with the normal tomatoes, Western blotting showed that the transgenic tomato protein contained a distinct protein band with a molecular weight about 60 kD. The results of ELISA suggested that fused foreign protein level was up to 0.18% of the total soluble protein in genetically modified tomato fruit. CONCLUSIONS: The target protein encoded by fused foreign gene of antigen epitope PacP in surface protein and cholera toxin B subunit was expressed in genetically modified tomatoes fruit.

Validated method to measure yakuchinone A in plasma by LC-MS/MS and its application to a pharmacokinetic study in rats.

BACKGROUND: Yakuchinone A has a plethora of beneficial biological effects. However, the pharmacokinetic (PK) data of yakuchinone A still remain unknown so far. Furthermore, the quantification of yakuchinone A in biological samples has not been reported in the literature. Therefore, in the present study we aimed to develop a new method for the fast, efficient and accurate assessment of yakuchinone A concentration in plasma, as a means for facilitating the PK evaluation of yakuchinone A. RESULTS: A liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the determination of yakuchinone A in rat plasma. Mass spectrometric and chromatographic conditions were optimized. Plasma samples were pretreated by protein precipitation with methanol. LC separation was performed on a Phenomenex Luna C18 column with gradient elution using a mobile phase consisting of methanol-water containing 0.5 mM formic acid (HCOOH) at a flow rate of 0.28 mL/min. ESI-MS spectra were acquired in positive ion multiple reaction monitoring mode (MRM). The precursor-to-product ion pairs used for MRM of yakuchinone A and yakuchinone B were m/z 313.1 → 137.0 and 311.2 → 117.1, respectively. Low concentration of HCOOH reduced the ion suppression caused by matrix components and clearly improved the analytical sensitivity. Yakuchinone A showed good linearity over a wide concentration range (r > 0.99). The accuracy, precision, stability and linearity were found to be within the acceptable criteria. This new method was successfully applied to analyze the rat plasma concentration of parent yakuchinone A after a single oral administration of SuoQuan capsules. Low systemic exposure to parent yakuchinone A was observed. CONCLUSION: The proposed method is sensitive and reliable. It is hoped that this new method will prove useful for the future PK studies.

Identification of known chemicals and their metabolites from Alpinia oxyphylla fruit extract in rat plasma using liquid chromatography/tandem mass spectrometry (LC-MS/MS) with selected reaction monitoring.

Alpinia oxyphylla (Yizhi) capsularfruits are commonly used in traditional medicine. Pharmacological studies have demonstrated that A. oxyphylla capsularfruits have some beneficial roles. Besides volatile oil, sesquiterpenes, diarylheptanoids and flavonoids are main bioactive constituents occurring in the Yizhi capsularfruits. The representative constituents include tectochrysin, izalpinin, chrysin, apigenin-4',7-dimethylether, kaempferide, yakuchinone A, yakuchinone B, oxyphyllacinol and nootkatone. Their content levels in the fruit and its pharmaceutical preparations have been reported by our group. The nine phytochemicals are also the major components present in the Yizhi alcoholic extracts, which have anti-diarrheal activities. However, the fates of these constituents in the body after oral or intravenous administration remain largely unknown. In the present study, we focus on these phytochemicals albeit other concomitant compounds. The chemicals and their metabolites in rat plasma were identified using liquid chromatography/tandem mass spectrometry with selected reaction monitoring mode after orally administered Yizhi extract to rats. Rat plasma samples were treated by methanol precipitation, acidic or enzymatic hydrolysis. This target analysis study revealed that: (1) low or trace plasma levels of parent chemicals were measured after p.o. administration of Yizhi extract, Suoquan capsules and pills to rats; (2) flavonoids and diarylheptanoids formed mainly monoglucuronide metabolites; however, diglucuronide metabolites for chrysin, izalpinin and kaempferide were also detected; (3) metabolic reduction of Yizhi diarylheptanoids occurred in rats. Yakuchinone B was reduced to yakuchinone A and then to oxyphyllacinol in a stepwise manner and subsequently glucuronidated by UDP-glucuronosyl transferase. Further research is needed to characterize the UDP-glucuronosyl transferase and reductase involved in the biotransformation of Yizhi chemicals.