Hollow fiber-stir bar sorptive extraction and microwave assisted derivatization of amino acids in biological matrices.

A kind of solid phase microextraction configuration combining the principles of hollow fiber solid phase microextraction (HF-SPME) and stir bar sorptive extraction (SBSE) is presented. The main feature of HF-SBSE is the use of microporous hollow fiber acting as the carrier and filter, while a thin stainless steel wire and silica microspheres in the lumen of hollow fiber respectively acting as the magnetic stirrer and the dispersed sorbents for the collection and extraction of the target analytes, thus affording extraction process like SBSE. Moreover, the prepared hollow fiber stir bar was applied to direct microextraction and microwave assisted derivatization with N,O-Bis(trimethylsilyl)trifluroacetamide (BSTFA) of four amino acids in rats' urine and cerebrospinal fluid followed by gas chromatography mass spectrometric analysis. The limits of detection for four amino acids were found to be in the range of 0.0003-0.017µgmL-1, and all the analytes did not exhibit any lack of fit. The extraction recoveries using HF-SBSE techniques ranged from 71.8% to 102.3%. The results indicated that hollow fiber stir bar sorptive extraction was a promising technique for the enrichment and direct derivatization of analytes extracted from biological matrices without sample clean-up.

Graphitic carbon nitrides modified hollow fiber solid phase microextraction for extraction and determination of uric acid in urine and serum coupled with gas chromatography-mass spectrometry.

An elevated uric acid (UA) in urine or serum can affect renal function and blood pressure, which is an indicator of gout, cardiovascular and renal diseases, hypertension, etc. In this work, a new type of mixed matrix membrane (MMM), based on graphitic carbon nitrides (g-CNs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine UA in urine and serum followed by gas chromatography-mass spectrometry (GC/MS). The porous g-CNs were dispersed in ammonia, and then the exfoliated g-CNs nanosheets were held in the pores of HF by capillary forces and sonification. The prepared g-CNs modified HF (g-CNs-HF) was immersed in biofluid directly to extract UA with SPME mode and the solvent-free mode is convenient for further derivatization and analysis. To achieve the highest extraction efficiency (EF), main extraction and derivatization parameters, such as g-CNs-HF immobilizing time, sonification power and time of extraction, derivatization and desorption time, were optimized. Under the optimum extraction conditions, a favorable linearity of UA was obtained in the range 0.1-200µgmL(-1) with correlation coefficients higher than 0.9990, and the average recoveries at three spiked levels of UA in urine and serum ranged from 80.7% to 121.6%, from 84.7% to 101.1%, respectively. The obtained results demonstrated the developed g-CNs-HF-SPME is a simple, rapid, cost-effective, solvent-free method for the analysis of UA in biofluid.

[Chemical constituents from flowers of Gardenia jasminoides].

OBJECTIVE: To study the chemical constituents from flowers of Gardenia jasminoides. METHODS: The compounds were isolated and purified by column chromatography and their structures were elucidated through spectroscopic techniques (NMR) and physicochemical properties. RESULTS: 15 compounds were isolated from flowers of G. jasminoides, and identified as 5, 7, 3'-trihydroxy-6, 4', 5'-trimethoxyflavone (1), 5, 7, 3', 5'- tetrahydroxy-6, 4'-dymethoxyflavone (2), kaempferol (3), quercetin (4), 3beta,23- dihydroxyurs-12-en-28-oic acid (5), 3beta,19alpha-dihydroxy-urs-12-en-28-oic acid (6), 3beta,19alpha,23-trihydroxy-urs-12-en-28-oic acid (7), emodin (8), physcion (9), crocin-I (10), beta-daucosterol (11), beta-sitosterol (12), stearic acid (13), palmitic acid (14), oleic acid (15). CONCLUSION: Compounds 1 - 15 are isolated from flowers of G. jasminoides and compounds 5 and 6 are isolated from genus Gardenia for the first time.

Two new tigliane diterpene esters from the flower buds of Daphne genkwa.

The phytochemical investigation of the flower buds of Daphne genkwa yielded four highly oxygenated tigliane diterpene esters (1-4), including two new phorbol derivatives, 12-O-(2'E,4'E-decadienoyl)-7-oxo-5-ene-phorbol-13-acetate (1) and 12-O-neodecanoyl-7-oxo-5-ene-phorbol-13-acetate (2). The molecular structures of the isolated compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR.

[Studies on the chemical constituents of Codonopsis pilosula].

OBJECTIVE: To study the chemical constituents of Codonopsis pilosula. METHODS: The compounds were isolated and purified by column chromatography and their structures were elucidated through spectroscopic techniques (NMR) and physicochemical properties. RESULTS: The compounds were isolated as hesperidin(I), n-hexyl beta-sophoroside(II), atractylenolide III (III), lobetyolin(IV), lobetyolinin(V), taraxerol(VI), taraxeryl acetate(VII), alpha-spinasterol(VIII),9,10,13-trihydroxy-(E)-11-octadecenoic acid (IX),beta-sitosterol(X),beta-daucosterol(XI)and sugar(XII). CONCLUSION: Compounds 1 -2 and 9 are isolated from this plant for the first time.

Several chromones from the stems of Polygonum aubertii Henry.

Two new 2-alkylchromanones, 2-tricosyl-2,5,7-trihydroxy-chromanone (6) and 2-pentacosyl-2,5,7-trihydroxy-chromanone (7), together with five known 2-alkylated chromones and chromanones (1-5), were isolated from the stems of Polygonum aubertii Henry. The structures of these compounds were established by spectroscopic methods including extensive 1D, 2D NMR ((1)H-(1)H COSY, HSQC, and HMBC), and HR-ESI-MS techniques. In addition, a plausible biosynthetic pathway for these compounds is described.

Ultrasonic cell grinder extraction of anthraquinones from radix et rhizoma Rhei and determination by ultra-performance liquid chromatography.

An ultrasonic cell grinder extraction (UCGE) method has been developed and applied to extract five anthraquinones (physcion, chrysophanol, emodin, rhein, and aloe-emodin) from radix et rhizoma Rhei. Several parameters of UCGE procedure, including ultrasonic cell grinder running mode, type and volume of extraction solvent and extraction time, were optimized. The determination was preformed on a Waters ultra-performance LC BEH C(18) column using gradient elution system. A baseline separation could be achieved in less than 7.5 min with high resolution. Under the optimized conditions, contents of physcion, chrysophanol, emodin, rhein and aloe-emodin in radix et rhizoma Rhei collected from different cultivated areas were 0-4.22, 0.11-27.64, 0.09-3.49, 0.31-3.31 and 0.13-2.93 mg/g, respectively. Compared with reflux, maceration and ultrasonic bath extractions, the UCGE method was more efficient, faster and easier to be operated, and required lower extraction temperature and less solvent. The results indicated that UCGE was a novel and ideal method for extracting bioactive constituents from plant samples.

Norsesquiterpene derivatives from the roots of Ligularia fischeri.

Four new norsesquiterpene derivatives with various rare skeletons: 1 beta-hydroxy-6 alpha-isobutyryloxy-9-noreremophil-7(11),8(10)-dien-8(12)-olide ( 1), 1 beta-acetoxy-6 alpha-isobutyryloxy-9-noreremophil-7(11),8(10)-dien-8(12)-olide ( 2), ligularate ( 3) and 9-oxoplatyphyllide ( 4), as well as four known sesquiterpenes, platyphyllide ( 5), 1-hydroxyplatyphyllide ( 6), 1 alpha-chloro-6 beta-isobutyryloxy-9-oxo-10 beta-hydroxyfuranoeremophilane ( 7), and 1 alpha-chloro-6 beta-angeloyloxy-9-oxo-10 beta-hydroxyfuranoeremophilane ( 8), have been isolated from an extract of the dried roots of Ligularia fischeri (Compositae). The structures of the new compounds were established by spectroscopic methods including extensive 2D NMR techniques ( (1)H- (1)H COSY, HMQC, HMBC and (1)H- (1)H NOESY) and HR-ESI-MS. In addition, a plausible biosyntheticpathway for compounds 1, 2 and 3 is described.

Applications of titania and zirconia hollow fibers in sorptive microextraction of N,N-dimethylacetamide from water sample.

The convenient fabrications of titania and zirconia hollow fiber with three-dimensional porous structure using polypropylene hollow fibers as templates were developed. And an analytical method based on enrichment and extraction of analytes in the water sample, hollow fiber sorptive microextraction in combined with gas chromatography has been developed for the rapid analysis of N,N-dimethylacetamide (DMA) in the environmental samples. The results showed that zirconia hollow fiber gave higher extraction performance of DMA than that of titania hollow fiber. The method validations, including linearity, limit of detection, limit of qualification, precision, and repeatability were investigated. Linearity for six-point calibration curve was excellent with zirconia hollow fiber having r2 value greater than 0.9993 at the linearity range of 0.001-1.0 mg mL(-1). In addition, it seems that hollow fiber sorptive extraction is a promising technique for the enrichment and purification of analytes extracted directly from liquid samples without any other pretreatment.

24-Hydroxyoleanane-type triterpenes from the aerial parts and roots of Oxytropis falcata.

Phytochemical investigation of the aerial parts of Oxytropis falcata led to the isolation of three new 24-hydroxyoleanane-type triterpenes (1-3), seven known analogues (4-10), and two rare sesquiterpenoids (12, 13). Compounds 6 and 12 were isolated as new natural products. Triterpenes (5, 6, 8, 11) were isolated from the roots of O. falcata. The structures and relative configurations of these compounds were elucidated by spectroscopic analyses, including 1D and 2D NMR spectroscopy and mass spectrometry, and by comparison of their NMR data with those of related compounds. Single-crystal X-ray diffraction analyses confirmed the structures of 1-4, and the absolute configuration of 3 was evidenced by the incorporation of DMSO (crystallization solvent) in the crystal lattice.

Determination of melamine residues in milk products by zirconia hollow fiber sorptive microextraction and gas chromatography-mass spectrometry.

News stories about the contamination of milk with melamine in China emerged on Sept 11, 2008, and the situation has since become an international health scare. In this work, a novel analytical method based on enrichment and pretreatment of analytes in the milk sample, hollow fiber sorptive extraction and gas chromatography-mass spectrometry has been developed for the rapid analysis of melamine in the dairy products. In the proposed method, melamine in the fresh milk was extracted by zirconia hollow fiber, enriching on zirconia coating of the hollow fiber, and then analyzed by GC-MS. The method validations including linearity, limit of detection, limit of qualification, recoveries at three different concentrations, precision, and repeatability were investigated. It was found that the proposed method provided linear range from 0.001 to 1000 microg/mL (r(2)=0.9997), low detection limit of 0.001 microg/mL, and preferable recoveries at three different concentrations. The obtained results demonstrated that zirconia hollow fiber combined with GC-MS is a simple, rapid and solvent-free method for the analysis of melamine in the dairy products.

Sesquiterpenoids from Valeriana tangutica.

A new guaiane-type sesquiterpenoid ethoxyvalerianol (1) and one known sesquiterpenoid valeranone (2) together with selina-4,7(11)-diene (3) and selinene (4), which were obtained from (+)-maaliol (5) by decyclization and dehydration, were isolated from Valeriana tangutica. Their structures were elucidated by 1D- and 2D-NMR spectroscopic data and HR-ESI-MS analysis.

Cytotoxic sesquiterpenes from Ligularia platyglossa.

Four sesquiterpene lactones including an eremophilenolide dimer, named as biligulaplenolide, 1, 8beta-hydroxy-1-oxo-(14alpha,15alpha eremophil-7(11),9(10)-dien-12,8alpha-olide, 2, 1-hydroxy-2-oxo-(14alpha,15alpha eremophil-1(10),7(11),8(9)-trien-12,8-olide, 3, 4alpha,8beta,9alpha-trihydroxy- 5alphaEta-7(11)-eudesmen-12,8alpha-olide, 4, along with two known ones, 10alpha-hydroxy-1-oxo-eremophil-7(11),8(9)-dien-12,8-olide, 5, and furanoeremophil-1(10)-ene-2,9-dione, 6, were isolated from the underground organs of Ligularia platyglossa (Franch.) Hand.-Mazz. Their structures were elucidated by spectroscopic methods including single-crystal X-ray diffraction analysis (2 and 3). Their in vitro cytotoxicities against seven cancer cell lines (BGC-823, A549, HL-60, B16, SMMC-7721, BEL7402, Hela) were evaluated. Compounds 2, 3, 5 showed cytotoxic activities on HL-60 cancer cells with IC50 in the range of 24.0 to 51.1 microM, whereas compound 3 exhibited only weak cytotoxic activity against the B16, BEL7402 and Hela cancer cells. Flow cytometric analysis indicated that compound 3 induces Hela cells to apoptotic death after 48 h treatment with 0.38 mM of this compound.

Phytochemical investigation of Anaphalis lactea.

Four new compounds, 2',6'-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-4'-methoxychalcone ( 1), 4,6-dihydroxy-7-isobutyryl-5-prenyl-2(3 H)-benzofuranone ( 4), 7- O-(beta- D-glucopyranosyloxy)-5-hydroxy-1(3 H)-isobenzofuranone ( 6) and (2 R,3 S)-3-methyl-2-(5-oxo-2-isopropenylhexyl)-cyclopentanone ( 7), along with thirteen known compounds were isolated from the whole plant of Anaphalis lactea. Their structures were established based on spectroscopic methods including IR, UV, MS, CD, 1 D NMR and 2 D NMR techniques. Compounds 2, 4 - 6 and 8 - 16 were tested for free-radical scavenging properties in the DPPH assays.

Dammarane- and taraxastane-type triterpenoids from Saussurea oligantha Franch.

A new dammarane triterpenoid oliganthas A (1) and a new taraxastane triterpenoid oliganthas B (2), as well as five known taraxastane triterpenoids, ptiloepoxide (3), taraxast-20(30)ene-3beta,21alpha-diol (4), 22-oxo-20-taraxasten-3beta-ol (5), taraxast-20-ene-3beta,30-diol (6), and taraxastane-3beta,20alpha-diol (7), were isolated from the whole plant of Saussurea oligantha Franch. Their structures were elucidated by a series of spectroscopic methods. These compounds, especially taraxastanes 2, 5, and 6, exhibited significant antibacterial activity against Actinomyces viscosus ATCC27044.

[Medicinal species of genus Polygonum s. lat. distributed in Anhui Province].

OBJECTIVE: To clarify the resource of medicinal plants of genus Polygonum s. lat. distributed in Anhui Province. METHOD: Conducting field investigation and consulting related specimens and data. RESULT AND CONCLUSION: The distribution, growing environment and medicinal use of 32 taxa have been clarified. A scientific basis for further study for these medicinal plants has been provided.

[Species of Ligularia in the northwestern China and their medicinal uses].

OBJECTIVE: To investigate the species of Ligularia distributed in the northwestern China and their medicinal uses in the local area. METHOD: Field investigation, specimen collection, taxonomic study and datum check were adopted. RESULT: There are 29 species and 1 varieties of Ligularia distributed in the northwestern China, and 18 species of them had been used as folk medicines with the function of resolving phlegm, relieving cough, clearing heat and toxins. CONCLUSION: The northwestern China is abundant in medicinal resource of Ligularia.