Determination of aflatoxins in medicinal herbs by HPLC. An efficient method for routine analysis

A fast and easy to perform method for the routine determination of aflatoxins in medicinal herbs was developed. The described method involves a single-step extraction with a non-chlorinated solvent, an immunoaffinity clean-up and HPLC with fluorescence detection. Whilst assays with naturally contaminated and with spiked samples of several herbs showed that the recoveries were somewhat low and dependent on the kind of sample and the degree of grinding, the intra-batch reproducibility was good, allowing a reliable quantitation by the standard-addition method. Good linearity, repeatability and accuracy were demonstrated in assays involving several medicinal herbs. The limit of quantitation was of the order of 0.05-0.1 ng/g, being dependent of the species analysed, and the method required no tedious concentration or back-extraction steps.     

Simple,sensitive and rapid HPLC–MS/MS method for the determination of cepharanthine in human plasma

A rapid, sensitive and specific method for the determination of cepharanthine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS/MS) was described. Cepharanthine and the internal standard (I.S.), telmisartan, were extracted from human plasma by methanol to precipitate the protein. A centrifuged upper layer was then evaporated and reconstituted with 100 μL methanol. Chromatographic separation was performed on an AGILENT XDB-C₈ column (150 mm × 2.1 mm, 5.0 μm, Agilent, USA) using a gradient mobile phase with 1 mmol/L ammonium acetate in water with 0.05% formic acid and methanol. Detection and quantitation was performed by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ion mode. The most intense [M+H]⁺ MRM transition of cepharanthine at m/z 607.3 → 365.3 was used for quantitation and the transition at m/z 515.5 → 276.4 was used to monitor telmisartan. The calibration curve was linear within the concentration range of 0.5–200.0 ng/mL (r = 0.9994). The limit of quantification (LOQ) was 0.5 ng/mL. The extraction recovery was above 81.1%. The accuracy was higher than 92.3%. The intra- and inter-day precisions were less than 9.66%. The method was accurate, sensitive and simple and was successfully applied to a pharmacokinetic study after single intravenous administration of 50 mg cepharanthine in 12 healthy Chinese volunteers.     

Iridoid and caffeoyl phenylethanoid glycosides of the endangered carnivorous plant Pinguicula lusitanica L. (Lentibulariaceae)

This work reports for the first time the identification of the major compounds of Pinguicula lusitanica, an endangered carnivorous plant species, using minimal amounts of plant material. A methanol extract was prepared from in vitro cultured plantlets and analyzed by HPLC–SPE–NMR/HPLC–MS. Three iridoid and five caffeoyl phenylethanoid glycosides were identified. These groups of natural compounds were previously reported in the Lentibulariaceae family and have been used as chemotaxonomic markers in related families.     

黄连木叶挥发油化学成分研究

采用水蒸气蒸馏法提取中药黄连木叶挥发油。通过气相色谱／质谱联用技术测定了提取物的化学成分,从中鉴定出99个化合物,主要含有多种长链脂肪烃、棕榈酸及芳樟醇等多种萜类化合物。初步分析了所含成分的药效。结果显示,黄连木叶有一定的药用价值。