Sulfoxide-Containing Polymer-Coated Nanoparticles Demonstrate Minimal Protein Fouling and Improved Blood Circulation.

Minimizing the interaction of nanomedicines with the mononuclear phagocytic system (MPS) is a critical challenge for their clinical translation. Conjugating polyethylene glycol (PEG) to nanomedicines is regarded as an effective approach to reducing the sequestration of nanomedicines by the MPS. However, recent concerns about the immunogenicity of PEG highlight the demand of alternative low-fouling polymers as innovative coating materials for nanoparticles.

Mass spectrometry-based strategies for screening of bioactive natural products.

Natural products (NPs) are combinatorial chemical libraries with diversities in chemical structures and pharmacological activities. Screening active compounds is in many cases an important factor in drug discovery. It was not easy to screen out the bioactive compounds from complex extracts consisting of many NPs.

Structural characterization and identification of oleanane-type triterpene saponins in Glycyrrhiza uralensis Fischer by rapid-resolution liquid chromatography coupled with time-of-flight mass spectrometry.

Oleanane-type triterpene saponins (OTS) are major active ingredients in Glycyrrhiza uralensis. In this work, a rapid-resolution liquid chromatography with time-of-flight mass spectrometry (RRLC/TOF-MS) method has been developed to characterize and identify OTS from G. uralensis.

Characterization and identification of steroidal alkaloids in Fritillaria species using liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

Liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI-QTOF-MS/MS) was performed to study the fragmentation behaviors of steroidal alkaloids from Fritillaria species, the antitussive and expectorant herbs widely used in traditional Chinese medicine. We propose, herein, a strategy that combining key diagnostic fragment ions and the relative abundances and amounts of major fragment ions (the ions exceeding 10% in abundance) to distinguish different sub-classes of Fritillaria alkaloids (FAs). It was found that hydrogen rearrangement and induction effects result in ring cleavage of the basic skeletons occurred in the MS/MS process and produced characteristic fragment ions, which are useful for structural elucidation.

Characterization and identification of saponins in Achyranthes bidentata by rapid-resolution liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

A rapid-resolution liquid chromatography (RRLC) method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) has been developed for analysis of oleanane-type triterpenoid saponins in Achyranthes bidentata. Collision-induced dissociation techniques were used to fragment the precursor molecular ions and the resulting product ions. A retro-Diels-Alder rearrangement from the oleanane aglycone skeleton in the MS/MS process yielded characteristic fragment ions in positive ion mode.

Chemical markers' fishing and knockout for holistic activity and interaction evaluation of the components in herbal medicines.

A strategy based on chemical markers' fishing and knockout has been proposed for holistic activity and interaction evaluation of the bioactive components in herbal medicines (HMs). It was devised to screen bioactive-compound group that represents the efficacy of HM, estimate the bioactivity contribution of each component and elucidate the interactions of multi-components. This strategy was accomplished through the following steps: (1) screen out the chemical markers (target peaks) in a HM fingerprint using online two-dimensional turbulent flow chromatography/liquid chromatography-mass spectrometry technique, (2) fish target peaks and knockout any interested peak, and (3) evaluate the bioactivities of fishing and knockout portions.

Characterization of novel astragaloside malonates from Radix Astragali by HPLC with ESI quadrupole TOF MS.

A structurally identified new compound named malonylastragaloside I was isolated and obtained from Radix Astragali. This novel compound was found to be unstable especially under high temperature and pH value. Using sonication extraction, addition of formic acid, and an efficient medium pressure ODS C(18) column chromatography method, a high yield of 40 mg of this compound was obtained from 150 g of powdered crude herbal medicine.

Turbulent-flow chromatography coupled on-line to fast high-performance liquid chromatography and mass spectrometry for simultaneous determination of verticine, verticinone and isoverticine in rat plasma.

A method based on the on-line turbulent-flow chromatography and fast high-performance liquid chromatography/mass spectrometry (TFC-LC/MS) was developed for sensitive and high throughput pharmacokinetic study of traditional Chinese medicines (TCMs). In this method, an on-line extraction column (Waters Oasis HLB) and a fast HPLC column with sub-2 microm particle size (Agilent Zorbax StableBond-C(18), 4.6 mm x 50 mm, 1.

Structural characterization and identification of iridoid glycosides, saponins, phenolic acids and flavonoids in Flos Lonicerae Japonicae by a fast liquid chromatography method with diode-array detection and time-of-flight mass spectrometry.

A fast liquid chromatography method with diode-array detection (DAD) and time-of-flight mass spectrometry (TOF-MS) has been developed for analysis of constituents in Flos Lonicerae Japonicae (FLJ), a traditional Chinese medicine derived from the flower bud of Lonicera japonica. The chromatographic analytical time decreased to 25 min without sacrificing resolution using a column packed with 1.8-microm porous particles (4.

Puqienine E: an angiotensin converting enzyme inhibitory steroidal alkaloid from Fritillaria puqiensis.

Eight steroidal alkaloids, puqienine A, puqienine B, puqienine C, puqienine D, puqienine E, puqietinone, puqiedine and peimisine were isolated from Fritillaria puqiensis G. D. Yu et.

Identification of metabolites of Danggui Buxue Tang in rat urine by liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry.

A method coupling liquid chromatography with electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOF/MS) has been developed for rapid and sensitive analysis of rat urinary metabolite profile of Danggui Buxue Tang (DBT), a well-known Chinese herbal formula. After oral administration of DBT, urine samples were collected during 0-24 h, and then pretreated by solid-phase extraction. A total of 68 compounds including 13 parent compounds and 55 metabolites were detected in the drug-containing urines compared with blank urines.

Herbal medicine analysis by liquid chromatography/time-of-flight mass spectrometry.

The fact that the effects of herbal medicines (HMs) are brought about by their chemical constituents has created a critical demand for powerful analytical tools performing the chemical analysis to assure their efficacy, safety and quality. Liquid chromatography coupled to mass spectrometry (LC-MS) is an excellent technique to analyze multi-components in complex herbal matrices. Due to its inherent characteristics of accurate mass measurements and high resolution, time-of-flight (TOF) MS is well-suited to this field, especially for qualitative applications.

Direct on-line analysis of neutral analytes by dual sweeping via complexation and organic solvent field enhancement in nonionic MEKC.

Conventionally, neutral compounds cannot be separated by nonionic micelle capillary electrophoresis. In this report, the development of a novel on-line preconcentration technique combining dual sweeping based on complexation and organic solvent field enhancement is applied to the sensitive and selective analysis of three neutral glucosides: ginsenoside Rf, ginsenoside Rg1, and ginsenoside Re. Nonionic micelle detectability by CE is demonstrated through effective focusing of large sample volumes (up to 38% capillary length) using a dual sweeping mode.

Rapid separation and identification of 54 major constituents in Buyang Huanwu decoction by ultra-fast HPLC system coupled with DAD-TOF/MS.

Buyang Huanwu Decoction (BYHWD), is a well-known traditional Chinese preparation consisting of Radix Astragali, Radix Angelicae Sinensis, Rhizoma Ligustici Chuanxiong, Radix paeoniae Rubra, Flos Carthami, Semen Persicae and Lumbricus. An ultra-fast high-performance liquid chromatography (HPLC) method coupled with diode array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) has been developed for rapid separation and structural identification of constituents in BYHWD. Using an ultra-fast HPLC system with short columns (4.

A novel flavanone from Ilex hainanensis Merr.

Chemical investigation of the leaves of Ilex hainanensis Merr. yielded a new flavanone named Huazhongilexone-7-O-beta-D-glucopyranoside, together with five known compounds, which included caffeic acid, quercetin, isoquercitrin, quercitrin-7-O-beta-D-glucopyranoside and rutin. All of the compounds were isolated from the plant for the first time.

Simultaneous determination of 6-gingerol, 8-gingerol, 10-gingerol and 6-shogaol in rat plasma by liquid chromatography-mass spectrometry: Application to pharmacokinetics.

A rapid high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed and validated for simultaneous quantification of 6-gingerol, 8-gingerol, 10-gingerol and 6-shogaol in rat plasma after oral administration of ginger oleoresin. Plasma samples extracted with a liquid-liquid extraction procedure were separated on an Agilent Zorbax StableBond-C(18) column (4.6 mm x 50 mm, 1.

High-speed separation and characterization of major constituents in Radix Paeoniae Rubra by fast high-performance liquid chromatography coupled with diode-array detection and time-of-flight mass spectrometry.

A fast high-performance liquid chromatography (HPLC) method coupled with diode-array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) has been developed for rapid separation and sensitive identification of major constituents in Radix Paeoniae Rubra (RPR). The total analysis time on a short column packed with 1.8-microm porous particles was about 20 min without a loss in resolution, six times faster than the performance of a conventional column analysis (115 min).

Pressure and electrokinetic injections for on-line sample stacking neutral analytes in microemulsion electrokinetic chromatography with salt-containing matrixes.

An on-line technique for pressure and electrokinetic injections of long sample plugs with simultaneous stacking of neutral analytes (notoginsenoside R(1), ginsenoside Rg(1), ginsenoside Rf, ginsenoside Rh(1), ginsenoside Rd, ginsenoside Rg3) in microemulsion electrokinetic chromatography is presented. The effects of salt concentration, sample plug length, organic modification of the sample matrix, oil phase and SDS concentration on stacking efficiency were examined in order to optimize the two injection methods. In microemulsion electrokinetic chromatography, the effect of the type of oil and SDS content on stacking mechanism is often sophisticated.

Complete assignments of 1H and 13C NMR spectral data for three new triterpenoid saponins from Ilex hainanensis Merr.

Three new oleanane-type triterpenoid saponins, ilexhainanoside C, D and E, all with 24, 28-dioic acid groups, were isolated from the leaves of Ilex hainanensis. They were 3beta-hydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(1), 3beta, 19alpha-dihydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(2) and 3beta, 29-dihydroxyolean-12-ene-24, 28-dioic acid-28-O-beta-D-glucopyranoside(3). The structures of these three new compounds were elucidated and complete assignments of the (1)H and (13)C NMR spectroscopic data were achieved by 1D and 2D NMR experiments [heteronuclear single quantum coherence (HSQC), HMBC and rotational nuclear Overhauser effect spectroscopy (ROESY)].

Application of liquid chromatography-electrospray ionization time-of-flight mass spectrometry for analysis and quality control of compound Danshen preparations.

A liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) method has been developed to evaluate the quality of three formulas of compound Danshen preparations (CDPs), through a simultaneous determination of 22 marker constituents (nine major phenolic acids, eight major saponins and five major diterpenoids). Optimum separations were obtained with a Zorbax C(18) column, using a gradient elution with 0.1% aqueous formic acid and acetonitrile.

Advances of modern chromatographic and electrophoretic methods in separation and analysis of flavonoids.

Flavonoids, one of the largest groups of secondary metabolites, are widespread in vegetable crops such as herbs, fruits, vegetables, grains, seeds and derived foods such as juices, wines, oils, etc. They receive considerable attention due to their biological and physiological importance. Hundreds of publications on the analysis of flavonoids have appeared over the past decade.

Identification of key metabolites of tectorigenin in rat urine by HPLC-MS(n).

This is a report about the identification of key metabolites of tectorigenin in rat urine using high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometric method (HPLC-ESI-MS(n)). Six healthy rats were administered a single dose (80 mg/kg) of tectorigenin by oral gavage. Urine was sampled for 0-24 h and centrifuged at 12,000 rpm for 10 min to obtain the supernatants, then the supernatants were purified by solid-phase extraction with a C(18) cartridge.

Identification of the major metabolites of tectorigenin in rat bile by liquid chromatography combined with time-of-flight and ion trap tandem mass spectrometry.

A novel methodology for the identification of tetorigenin and its metabolites in rat bile has been created using liquid chromatography (LC) combined with time-of-flight (TOF) and ion trap multiple mass spectrometry (IT-MSn). As a means to discriminate amongst unknown organic compounds in complex biological matrices, the proposed methodology relies upon the combination of LC/TOF-MS to provide accurate mass measurements in generating a molecular formula while benefiting from the complementary structural information provided by the LC/IT-MSn. In this study, the combined approach has been applied to the metabolic fingerprinting chromatograms of rat bile samples before and after tectorigenin administration.

Rapid and sensitive screening and characterization of phenolic acids, phthalides, saponins and isoflavonoids in Danggui Buxue Tang by rapid resolution liquid chromatography/diode-array detection coupled with time-of-flight mass spectrometry.

A novel rapid resolution liquid chromatography (RRLC) method coupled with diode-array detection (DAD) and time-of-flight mass spectrometry (TOFMS) in both positive and negative modes has been developed for quick and sensitive identification of the major compounds in Danggui Buxue Tang (DBT) preparation. Significant advantages of the use of RRLC with 1.8-microm porous particles include the much higher speed of chromatographic separation and great enhancement in sensitivity, compared with the conventional high-performance liquid chromatography (HPLC).

Structural determination of two new triterpenoids from Potentilla discolor Bunge by NMR techniques.

Two new pentacyclic triterpenoids, 3alpha, 30-dihydroxylup-20(29)-en-27-oic acid (1) and (20S)-3alpha, 29-dihydroxylupan-27-oic acid (2) were isolated from the whole herbs of Potentilla discolor Bunge. The structures of these two new compounds were elucidated, and complete assignments of the (1)H and (13)C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HSQC, HMBC, (1)H-(1)HCOSY and ROESY).