Determination of three triterpene alcohols in rat plasma after oral administration of pollen of Brassica campestris based on the utilization of fetal bovine serum as surrogate matrix.

24-Dehydropollinstanol (DEH), 24-methylene cholesterol (MET) and 31-norcycloartenol (NOR) are the functional triterpene alcohols of pollen of Brassica campestris. To study the pharmacokinetics of the above components of pollen of B. campestris in rats, a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed. To avoid the interference of endogenous MET in rat plasma, fetal bovine serum (FBS) was selected as surrogate matrix and validated. Rat plasma was liquid-liquid extracted, then the chromatographic separation was conducted on a poroshell 120 SB C18 column (2.7µm, 2.1mm×50mm) at 38°C within 5.6min utilizing a gradient elution with a mobile phase consisting of (A) 0.1% formic acid in water and (B) 0.1% formic acid in methanol. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode using positive atmospheric pressure chemical ionization (APCI). The method was validated over the concentration of 9.8-1560ng/ml; the inter-and-intra-day precisions (RSD %) were ≤7.8%, and the accuracies (RE %) were -5.3% to 12.2%, the extraction recovery ranged from 73.5% to 106.9% for all of these analytes, and no obvious matrix effect was observed. The developed method was applied successfully to study the pharmacokinetics of DEH, MET and NOR in rats after oral administration of pollen of B. campestris.

Bioefficacy of Alpinia galanga (Zingiberaceae) rhizome extracts, (E)-p-acetoxycinnamyl alcohol, and (E)-p-coumaryl alcohol ethyl ether against Bactrocera dorsalis (Diptera: Tephritidae) and the impact on detoxification enzyme activities.

The application of insecticides to control oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), is a principal component of the current management of these fruit flies. However, we evaluated four extracts of Alpinia galanga Wild Linn (Zingiberaceae) rhizomes against adult flies and found hexane and ethanol extracts to be most effective (LC50 = 4,866 and 6,337 ppm, respectively, after 24 h). This suggested that both nonpolar and polar compounds could be active in the candidate plant. Accordingly, the hexane extract was further processed to isolate nonpolar active compounds from this plant source. Two compounds, (E)-p-acetoxycinnamyl alcohol and (E)-p-coumaryl alcohol ethyl ether, were identified as active ingredients and found to be more active than total hexane extract (LC50 = 3,654 and 4,044 ppm, respectively, after 24 h). The data suggested that the compounds were not synergistic but may have some additive effect in a mixture. The activity of the hexane extract against detoxification enzymes, carboxylesterase (CE) and glutathione transferase (GST) also was determined in vitro. CE was inhibited by 70%, whereas GST was not significantly inhibited. Insect CEs mediate insecticide resistance via their induction; therefore, inhibition of these enzymes by plant allelochemicals could be a useful alternative approach for the management of the pest in the field.

A rapid and simple RP-HPLC method for quantification of kirenol in rat plasma after oral administration and its application to pharmacokinetic study.

A rapid and simple reverse-phase high-performance liquid chromatography (RP-HPLC) was developed and validated for the quantification of kirenol in rat plasma after oral administration. Kirenol and darutoside (internal standard, IS) were extracted from rat plasma using Cleanert™ C(18) solid-phase extraction (SPE) cartridge. Analysis of the extraction was performed on a Thermo ODS-2 Hypersil C(18) reversed-phase column with a gradient eluent composed of acetonitrile and 0.1% phosphoric acid. The flow rate was 1.0 mL/min and the detection wavelength was set at 215 nm. The calibration curve was linear over the range of 9.756-133.333 µg/mL (r(2) = 0.9991) in rat plasma. The lower limits of detection and quantification were 2.857 and 9.756 µg/mL, respectively. The intra- and inter-day precisions (relative standard deviation, RSD) were between 2.24 and 4.46%, with accuracies ranging from 91.80 to 102.74%. The extraction recovery ranged from 98.16 to 107.62% with RSD less than 4.81%. Stability studies showed that kirenol was stable in preparation and analytical process. The present method was successfully applied to the pharmacokinetic study of kirenol in male Sprague-Dawley rats after oral administration at a dose of 50 mg/kg.