Structurally diverse analgesic diterpenoids from the flowers of Rhododendron molle.

Thirteen diterpenoids (1-13), classified into four structurally diverse carbon skeletons, including 1,5-seco-kalmane (1 and 6), grayanane (2-11), kalmane (12), and rhodomollane (13), were isolated from the flowers extract of Rhododendron molle. Among them, rhodomollinols A - E (1-5) were five new diterpenoids and their structures were elucidated by extensive spectroscopic methods including HRESIMS, UV, IR, 1D and 2D NMR, as well as quantum ECD calculations. Rhodomollinol A (1) is the first representative of a 6-deoxy-1,5-seco-kalmane diterpenoid. The abnormal NMR phenomenon of the presence of only 9 carbon resonances instead of 20 carbons in the 13C NMR spectrum of 1 was observed and elucidated by the quantum NMR calculations. All diterpenoids 1-13 showed significant analgesic activities in an acetic acid-induced writhing model. It's the first time to report the analgesic activity of a rhodomollane-type diterpenoid. At a dose of 1.0 mg/kg, diterpenoids 1-3, 6, 8, 9, and 12 reduced the writhe numbers with inhibition rates over 50%, and 9 exhibited stronger analgesic activity with a writhe inhibition rate of 89.7% than that of the positive control morphine. Importantly, even at the lowest dose of 0.04 mg/kg, rhodomollinols A (1) and B (2), rhodomollein X (7), and 2-O-methylrhodojaponin VI (9) still showed more potent analgesic effects than morphine with the writhe inhibition rates of 51.8%, 48.0%, 61.7%, and 60.0%, respectively. A preliminary structure-activity relationship might provide some clues to design potential analgesics on the basis of structurally diverse Ericaceae diterpenoids.

Discovery of highly functionalized grayanane diterpenoids from the flowers of Rhododendron molle as potent analgesics.

A systematical investigation on the chemical constituents of the flowers of Rhododendron molle (Ericaceae) led to the isolation and characterization of thirty-eight highly functionalized grayanane diterpenoids (1-38), including twelve novel analogues molleblossomins A-L (1-12). Their structures were elucidated by comprehensive methods, including 1D and 2D NMR analysis, calculated ECD, 13C NMR calculations with DP4+ probability analysis, and single crystal X-ray diffraction. Molleblossomins A (1), B (2), and E (5) are the first representatives of 2ß,3ß:9ß,10ß-diepoxygrayanane, 2,3-epoxygrayan-9(11)-ene, and 5,9-epoxygrayan-1(10),2(3)-diene diterpenoids, respectively. Molleblossomins G (7) and H (8) represent the first examples of 1,3-dioxolane-grayanane conjugates furnished with the acetaldehyde and 4-hydroxylbenzylidene acetal moieties, respectively. All grayanane diterpenoids 1-38 were screened for their analgesic activities in the acetic acid-induced writhing model, and all of them exhibited significant analgesic activities. Diterpenoids 6, 13, 14, 17, 20, and 25 showed more potent analgesic effects than morphine at a lower dose of 0.2 mg/kg, with the inhibition rates of 51.4%, 68.2%, 94.1%, 66.9%, 97.7%, and 60.0%, respectively. More importantly, even at the lowest dose of 0.04 mg/kg, rhodomollein X (14), rhodojaponin VI (20), and rhodojaponin VII (22) still significantly reduced the number of writhes in the acetic acid-induced pain model with the percentages of 61.7%, 85.8%, and 64.6%, respectively. The structure-activity relationship was summarized and might provide some hints to design novel analgesics based on the functionalized grayanane diterpenoids.

Application of supramolecular solvent based on the surface-active ionic liquid in dispersive liquid-liquid microextraction of triazine herbicides in tea samples.

In this study, a novel supramolecular solvent based on surface-active ionic liquid was prepared and used as an extraction solvent for dispersive liquid-liquid microextraction of four triazine herbicides in tea samples. The formation mechanism, microstructure and physicochemical properties of supramolecular solvent were studied. Some parameters, including the molar ratio of surface-active ionic liquid to tetrahydrofuran, volume of supramolecular solvent, vortex time, pH of sample solution, type and amount of salt, were investigated and optimized. The good linearities (r > 0.9990) for the analytes were obtained. The limits of detection and quantification for triazine herbicides were in the range of 1.7-2.1 µg kg-1 and 5.6-7.1 µg kg-1, respectively. The spiked recoveries were 80.0-119.9 %. The supramolecular solvent prepared in this study has the advantages of simple preparation process, low viscosity and good dispersibility. It can be used for the extraction and enrichment of trace triazine herbicides in tea samples.

Lanostane triterpene glycosides from the flowers of Lyonia ovalifolia var. hebecarpa and their antiproliferative activities.

Sixteen lanostane-type triterpene glycosides including eight new ones, named lyonicarposides A-H (1-8), were isolated from the flowers of Lyonia ovalifolia var. hebecarpa (Franch. ex F.B. Forbes & Hemsl.) Chun (Ericaceae). The chemical structures of the new compounds were elucidated by the comprehensive spectroscopic techniques and chemical methods. The Mo2(OAc)4-induced electronic circular dichroism method was used to determine the absolute configurations of C-24 in lyonicarposides A (1), C (3), and E (5). This is the first phytochemical study on the flowers of L. ovalifolia var. hebecarpa. All the isolates were evaluated for their antiproliferative activities against SMMC-7721, HL-60, SW480, MCF-7, and A-549 cell lines. Lyonicarposides A (1) and B (2) showed moderate antiproliferative activities against five cancer cell lines with IC50 values ranging from 12.39 to 28.71 µM. Lyonicarposides C (3) and G (7) and lyonifoloside M (12) selectively inhibited the proliferation of HL-60 and MCF-7 cell lines with IC50 values ranging from 13.03 to 17.71 µM. Interestingly, lyonifoloside L (13) selectively inhibited the proliferation of MCF-7 cell line with an IC50 value of 16.27 µM. Their structure-activity-relationships were discussed.

Rhodojaponin II attenuates kidney injury by regulating TGF-ß1/Smad pathway in mice with adriamycin nephropathy.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhododendron molle G. Don (Ericaceae) (RM) is a natural medicinal plant. Its root extracts have been applied in clinic and proved to be effective in chronic glomerulonephritis and rheumatoid arthritis in China. Surprising, little is understood about the key compound of RM and the exact mechanisms underlying its treatment on kidney diseases. In this study, we will explore whether rhodojaponin II (R-II), as the important compound of RM, also exerts the major effect. MATERIALS AND METHODS: Mouse model of focal segmental glomerulosclerosis was induced by single dose of adriamycin injection. Induced adriamycin nephropathy (ADRN) mice were treated individually with RM root extract (5 mg/kg, n = 5), RM root extract (60 mg/kg, n = 5), R-II (0.04 mg/kg, n = 6) or captopril (30 mg/kg, n = 5) for five weeks. Podocyte marker (nephrin and podocin) expressions were examined by immunohistochemical staining and Western Blot analysis. Fibronectin level was evaluated by immunohistochemical staining and Western Blot analysis. Interstitial infiltrated inflammatory cells (CD4+ T cells, CD8+ T cells, and CD68+ macrophages) were examined with immunohistochemical staining. The expressions of NF-ĸB p-p65 and TGF-ß1/Smad pathway associated key proteins, such as TGF-ß1, Smad3, phosphorylated-Smad3 (p-Smad3), and Smad7, were analyzed respectively by Western Blot analysis. RESULTS: RM root extract (5 mg/kg) and its important compound R-II (0.04 mg/kg) significantly ameliorated proteinuria, podocyte injury, and glomerulosclerosis, meanwhile, they hampered interstitial fibrosis in mice with ADRN. R-II significantly reduced NF-ĸB p65 phosphorylation, interstitial infiltrated CD4+ T cells, CD8+ T cells, and CD68+ macrophages, at the same time, down-regulated TGF-ß1 and p-Smad3 protein expressions in mice with ADRN. CONCLUSION: RM root extract, R-II, could effectively ameliorate proteinuria and kidney injury in ADRN, related to its anti-inflammatory effects, as well as suppression of TGF-ß1/Smad signaling pathway.

Sesquiterpenoids with diverse carbon skeletons from the roots of Cichorium glandulosum and their anti-inflammatory activities.

A total of thirteen sesquiterpenoids with diverse skeletons including four new sesquiterpenoids, glandulosines A - D (1-4), a new natural product, glandulosine E (5), and eight known sesquiterpene lactones (6-13) were isolated from the roots of Cichorium glandulosum Boiss. et Huet (Asteraceae). Their structures were determined by extensive spectroscopic experiments including NMR, electronic circular dichroism (ECD), calculated ECD, Rh2(OCOCF3)4-induced ECD, and single-crystal X-ray diffraction analysis, as well as chemical methods. This is the first report of the crystal structure of 11ß,13-dihydrolactucin (11). Thirteen isolated sesquiterpenoids (1-13) were evaluated for their anti-inflammatory activities in vitro, and three guaiane sesquiterpene lactones, glandulosine E (5), scorzoside (9), and lactucin (10) showed moderate inhibitory activity against LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages.

Rhodomicranosides A-I, analgesic diterpene glucosides with diverse carbon skeletons from Rhododendron micranthum.

Nine previously undescribed diterpene glucosides, rhodomicranosides A-I, comprising leucothane, 4,5-seco-ent-kaurane, and grayanane types, respectively, were isolated from the leaves of Rhododendron micranthum, along with seven known diterpenoids. Their structures were elucidated based on extensive spectroscopic analyses such as HRESIMS, 1D and 2D NMR, UV, and IR, and their absolute configurations were determined by various methods including X-ray diffraction analysis, electronic circular dichroism spectroscopy (ECD), calculated ECD, and Mo2(OAc)4-induced ECD, as well as chemical methods. This is the first time to report the crystal structures of leucothane diterpene glycosides. Rhodomicranosides A-C represent the first examples of 15α-hydroxy-leucothane diterpenoids, leucothane diterpene diglucosides, and 9ß-hydroxy-leucothane diterpenoids, respectively. Rhodomicranosides D and E are the second and third examples of 4,5-seco-ent-kaurane diterpenoids, and this is the first time to report 4,5-seco-ent-kaurane-type diterpenoids from the genus of Rhododendron. Rhodomicranosides F and G are the first examples of 5α-H-grayan-1(10),9(11)-diene-6-one diterpenoids. Some isolated diterpenoids were evaluated for their analgesic activity in an acetic acid-induced writhing test, and rhodomicranosides A-E and H, pierisformoside F, iso-grayanotoxin II, and grayanotoxins I, III, and IV showed significant analgesic effects with the percentage inhibitions over 50% at the dose of 1.0 mg/kg. In particular, grayanotoxins I and III exhibited more potent analgesic activity than morphine at a dose of 0.2 mg/kg, and they showed significant analgesic activity even at a lower dose of 0.04 mg/kg with the inhibition rates of 71.5% and 69.3%, respectively. Their preliminary structure-activity relationships were discussed.

Ionic liquid-based salt-induced liquid-liquid extraction of polyphenols and anthraquinones in Polygonum cuspidatum.

Ionic liquid-based salt-induced liquid-liquid extraction was developed for the first time and applied to the extraction of four active constituents, including polydatin, resveratrol, emodin, and physcion in Polygonum cuspidatum (P. cuspidatum). In this study, ionic liquid was used as extraction solvent. The dried P. cuspidatum samples purchased from the pharmacy were triturated and passed through a 120-mesh sieve. The obtained sample powders were dried to constant weight at 55 ℃, and then mixed with extraction solvent. The extraction was carried out with the aid of ultrasound. Three phases, including ionic liquid-rich, salt-rich and solid sample phases were formed in the presence of salt. The target analytes were enriched in ionic liquid phase and then determined by high performance liquid chromatography. The experimental parameters, such as type and volume of ionic liquid, type and amount of salt, pH value of extraction medium, ultrasound power, ultrasound time and centrifugal condition, were optimized. The calibration curves showed good linear relationship (r > 0.9994). The limits of detection and quantification were in the range of 2.8-29.5 and 9.4-98.3 ng mL-1, respectively. The spiked recoveries were between 92.16% and 105.41%. Compared with hot reflux extraction and ultrasound-assisted extraction, the proposed method requires less extraction solvent and time. The present method can be applied to the determination of polyphenols and anthraquinones in P. cuspidatum.

Grayanane Diterpenoid Glucosides from the Leaves of Rhododendron micranthum and Their Bioactivities Evaluation.

Thirteen new grayanane diterpenoid glucosides, 3- epi-grayanoside B (1), micranthanosides A-E (2-6), 7α-hydroxygrayanoside C (7), micranthanoside F (8), 14ß-acetyoxymicranthanoside F (9), micranthanoside G (10), 14- O-acetylmicranthanoside G (11), 14ß-hydroxypieroside A (12), and micranthanoside H (13), and six known analogues (14-19) were isolated from the leaves of Rhododendron micranthum. The structures of 1-19 were elucidated based on spectroscopic analysis, comparison with literature, and chemical methods. The absolute configurations of 3- epi-grayanoside B (1) and micranthanosides A (2) and C (4) were defined by single-crystal X-ray diffraction analysis. This is the first report of the crystal structures of grayanane diterpenoid glucosides. 3- epi-Grayanoside B (1) represents the first example of a 3α-oxygrayanane diterpenoid glucoside, and micranthanosides A-D (2-5) are the first examples of 5α-hydroxy-1-ß H-grayanane diterpenoids. In addition, micranthanosides C-F (4-6 and 8) and 14ß-acetyoxymicranthanoside F (9) represent the first examples of grayanane glucosides with the glucosylation at C-16. All the grayanane diterpenoid glucosides 1-19 were assayed for their anti-inflammatory, antitumor, and PTP1B inhibitory activities, but did not show significant activities at 40 µM. Grayanane diterpenoid glucosides 1-18 were evaluated for their antinociceptive activity, and compounds 2, 3, 7-10, 12, 13, and 16 showed significant antinociceptive effects with percentage inhibitions in excess of 50%.

Anti-inflammatory Grayanane Diterpenoids from the Leaves of Rhododendron molle.

Thirteen new grayanane diterpenoids (1-13), a new dimeric grayanane diterpenoid, bimollfoliagein A (14), and 15 known analogues (15-29) were isolated from the leaves of Rhododendron molle. The structures of the new compounds (1-14) were determined by extensive spectroscopic data interpretation. The absolute configurations of 1-3, 7, 8, 16, 18, and 24 were defined by single-crystal X-ray diffraction analysis. Mollfoliagein A (1) represents the first example of a 2,3:11,16-diepoxy grayanane diterpenoid, featuring a cis/trans/cis/cis/trans-fused 3/5/7/6/5/5 hexacyclic ring system with a 7,13-dioxahexacyclo[10.3.3.01,11.04,9.06,8.014,17]octadecane scaffold. Diterpenoids 1-29 were evaluated for their anti-inflammatory activities in vitro, and 15, 16, 18, 19, 23-26, 28, and 29 exhibited significant inhibitory activities against nitric oxide production in lipopolysaccharide-induced RAW264.7 mouse macrophages with IC50 values ranging from 2.8 to 35.4 µM. A preliminary structure-activity relationship for the anti-inflammatory activity of diterpenoids 1-29 is discussed.

Matrix Solid-Phase Dispersion Coupled with High-Performance Liquid Chromatography Diode Array Detection for Simultaneous Determination of Four Lipophilic Constituents from Salvia miltiorrhiza Bunge.

A simple, rapid and efficient method based on matrix solid-phase dispersion coupled with high-performance liquid chromatography was developed for determination of lipophilic constituents, including dihydrotanshinone, tanshinone I, cryptotanshinone and tanshinone II A in Salvia miltiorrhiza Bunge Box-Behnken design was employed for optimization of the extraction conditions of matrix solid-phase dispersion, including mass ratio of dispersant to sample, volume of elution solvent, and amount of cleanup reagent. The optimal experimental results were obtained using 0.27 g of acid alumina as dispersant, 13 mL of acetonitrile as elution solvent and 0.36 g of acid alumina as cleanup reagent. The target analytes was determined by high-performance liquid chromatography. The recoveries of tanshinones obtained by analyzing the spiked samples were from 83.81% to 93.74% and relative standard deviations from 2.87% to 6.83%. Matrix solid-phase dispersion integrated the extraction and cleanup into a single step, which provides the advantages of being simple, fast and convenient. Compared with other conventional methods, the present method consumed less time and less organic solvent. The results demonstrate that this method has potential for the determination of active constituents and the quality control of traditional Chinese medicine.

Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140µL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088µgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant.

Dynamic microwave-assisted extraction online coupled with single drop microextraction of organophosphorus pesticides in tea samples.

A new method for the determination of seven organophosphorus pesticides was developed using dynamic microwave-assisted extraction online coupled with single drop microextraction prior to gas chromatographic mass spectrometry (GC-MS). The method combines the advantages of dynamic microwave-assisted extraction and single-drop microextraction, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, tea samples were extracted with 25% ethanol aqueous solution and purified with acidic alumina at the same time, and then the analytes were concentrated into microextraction solvent. When the extraction was completed, the solvent microdrop containing the enriched analytes was retracted into the microsyringe and directly analyzed by GC-MS without any filtration or cleanup step. The method makes extraction, cleanup, separation, and enrichment to be carried out in one step. Several experimental parameters, including type of extraction solvent, type and amount of dispersant, type and volume of microextraction solvent, microwave power, extraction time, and flow rate of extraction solvent were investigated and optimized. Under optimal experimental conditions, good linearity was observed in the range of 2.00-500.00 µg kg(-1). The limits of detection and quantification were in the range of 0.4-1.7 µg kg(-1) and 1.1-5.6 µg kg(-1), respectively. The present method was applied to the analysis of tea samples, and the recoveries of analytes were in the range of 84.9-106.4% with the relative standard deviations ranging from 1.0 to 6.1%. The results showed that the present method was a rapid and feasible method for the determination of organophosphorus pesticides in tea samples.

Dispersive micro-solid-phase extraction of herbicides in vegetable oil with metal-organic framework MIL-101.

Dispersive microsolid-phase extraction based on metal-organic framework has been developed and applied to the extraction of triazine and phenylurea herbicides in vegetable oils in this work. The herbicides were directly extracted with MIL-101 from diluted vegetables oils without any further cleanup. The separation and determination of herbicides were carried out on high performance liquid chromatography. The effects of experimental parameters, including volume ratio of n-hexane to oil sample, mass of MIL-101, extraction time, centrifugation time, eluting solvent, and elution time were investigated. The Student's t test was applied to evaluate the selected experimental conditions. The limits of detection for the herbicides ranged from 0.585 to 1.04 µg/L. The recoveries of the herbicides ranged from 87.3 to 107%. Our results showed that the present method is rapid, simple, and effective for extracting herbicides in vegetable oils.

Ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction high-performance liquid chromatography for determination of tanshinones in Salvia miltiorrhiza Bge. root.

The ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction has been developed and applied to the extraction of four tanshinones, including dihydrotanshinone, tanshinone I, cryptotanshinone and tanshinone IIA in Salvia miltiorrhiza Bge. root. High performance liquid chromatography was applied to the separation and determination of the analytes. The ionic liquid was used as extraction solvent and target analytes were extracted with help of ultrasound. Then, ion-pairing agent was added into the sample solution, which resulted in the formation of water-insoluble ionic liquid in the solution. The phase separation was performed by centrifugation. The extraction, concentration and purification of target analytes were performed simultaneously. The experimental parameters, including type and volume of ionic liquid, sample amount, the size of sample particle, pH value of extraction medium, extraction temperature, extraction time, amount of ion-pairing agent and centrifuging time, were investigated and optimized. The calibration curves showed good linear relationship (r>0.9997). The limits of detection and quantification were in the range of 0.052-0.093 and 0.17-0.31 µg mL(-1), respectively. The recoveries were between 70.45% and 94.23% with relative standard deviations lower than 5.31%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with UAE and HRE. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.

Magnetic ionic liquid-based dispersive liquid-liquid microextraction for the determination of triazine herbicides in vegetable oils by liquid chromatography.

Magnetic ionic liquid-based dispersive liquid-liquid microextraction (MIL-based DLLME) was developed for extracting triazine herbicides from vegetable oils. The MIL, 1-hexyl-3-methylimidazolium tetrachloroferrate ([C6mim] [FeCl4]), was used as the microextraction solvent. The magnetic separation time was shortened by simply mixing carbonyl iron powder with the MIL in the sample after DLLME. The effects of several important experimental parameters, including the amount of MIL, the time of ultrasonic extraction, the type and the volume of cleanup solvent were investigated. The MIL-based DLLME coupled with liquid chromatography gave the limits of detection of 1.31-1.49ngmL(-1) and limits of quantification of 4.33-4.91 ng mL(-1) for triazine herbicides. When the present method was applied to the analysis of vegetable oil samples, the obtained recoveries were in the range of 81.8-114.2% and the relative standard deviations were lower than 7.7%. Compared with existing methods, the performances achieved by the present method were acceptable.

Determination of five pyrethroids in tea drinks by dispersive solid phase extraction with polyaniline-coated magnetic particles.

The polyaniline-coated magnetic particles with bowl-shaped morphology (Fe3O4/C/PANI microbowls) were successfully prepared and characterized by scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. The prepared microbowls were used as the magnetic adsorbent in dispersive solid phase extraction of five pyrethroids, including cyhalothrin, beta-cypermethrin, esfenvalerate, permethrin and bifenthrin in plain tea drinks. The effects of experiment factors, including amount of Fe3O4/C/PANI microbowls, pH value, ultrasound extraction time and desorption conditions, were investigated. The extraction recoveries obtained with 8 mg of magnetic microbowls were satisfactory, and the microbowls can be reused after easy washing. Thus, a simple, selective and effective method for the determination of the pyrethroids was established successfully. The results showed that the method had good linearity (r=0.9992-0.9998), and the limits of detections (LODs) were from 0.025 to 0.032 ng mL(-1). The intra-day and inter-day relative standard deviations (RSDs) were in the range of 2.4-6.1% and 3.5-8.8%, respectively. Recoveries obtained by analyzing the real tea drinks were in the range of 72.1-118.4%.

Simultaneous determination of nucleosides and their bases in Cordyceps sinensis and its substitutes by matrix solid-phase dispersion extraction and HPLC.

Nine nucleosides and nucleobases, including uracil, adenine, thymine, uridine, adenosine, thymidine, cytidine, guanosine, and cordycepin in natural Cordyceps sinensis, cultured Cordyceps mycelia, and Cordyceps fruiting bodies were extracted by matrix solid-phase dispersion (MSPD) and determined by HPLC. The experimental conditions for the MSPD extraction were optimized. Florisil was used as dispersant, petroleum ether as washing solvent, and methanol as elution solvent. The Florisil-to-sample ratio was selected to be 4:1 and no additional clean-up sorbent was needed. The calibration curves had good linear relationships (r > 0.9997). The LOD and LOQ were in the range of 12～79 and 41～265 ng/mL, respectively. The intra- and interday precision were lower than 8.3%. The recoveries were between 61.5 and 93.2%. The present method consumed less sample compared with ultrasonic extraction and heating reflux extraction (HRE). The extraction yields obtained by using the present method are much higher than those obtained by UE and comparable to those obtained by HRE.

On-line ionic liquid-based dynamic microwave-assisted extraction-high performance liquid chromatography for the determination of lipophilic constituents in root of Salvia miltiorrhiza Bunge.

On-line continuous sampling, ionic liquid-based dynamic microwave-assisted extraction high performance liquid chromatography has been developed and applied to the extraction of lipophilic constituents from root of Salvia miltiorrhiza Bunge. Several operating parameters were optimized by single-factor and Box-Behnken design experiments. The type and concentration of ionic liquids, power of microwave irradiation, flow rate of sample suspension, amount, and particle size of sample were investigated. The limits of detection for tanshin-one I, cryptotanshinone, and tanshinone II(A) are 0.014, 0.009, and 0.009 mg/g, respectively. The RSDs of interday and intraday were lower than 2.02 and 2.16%, respectively. The recoveries for target analytes were in the range of 90.7-101.8%. The homogeneity of the suspension and stability of the analytes were investigated and the results were satisfactory. The proposed method was compared with the off-line ionic liquid-based dynamic microwave-assisted extraction, off-line ethanol-based dynamic microwave-assisted extraction, ionic liquid-based ultrasonic-assisted extraction, and ionic liquid-based maceration extraction. The results indicated that the proposed method is effective for the extraction of the active components in Chinese herbal medicine and has some advantages over the other methods.

Pneumatic nebulization gas-solid extraction of some pesticides in liquor.

In general, solid phase extraction (SPE) was applied to the separation and concentration of analytes from liquid samples. However, the SPE generally cannot be applied directly to the separation and concentration of analytes from liquor in which the concentration of ethanol is high, because the ethanol can elute the analytes from the SPE column and the analytes can hardly been adsorbed onto the column. In the work, the pneumatic nebulization coupled with gas-solid extraction (PN-GSE) was applied to the extraction of several pesticides, including fenuron, chlortoluron, karmex, linuron and prebane, from liquor samples. The high concentration of ethanol in the liquor samples cannot elute the analytes from the SPE column. The high performance liquid chromatography was applied to the separation and determination of the analytes. Experimental parameters affecting the performances of PN-GSE, such as types and amount of packed material of the column, temperature of the spray chamber, flow rate of carrier gas, pumping rate of gas and volume of elution solvent were examined and optimized. The limits of detection for the analytes were in the range of 0.19-0.26 µg L⁻¹. Liquor samples were analyzed and the recoveries of the analytes in spiked samples were from 91.0 to 106.3%. The relative standard deviations were lower than 6.5%.