Phenolic composition of four sage species: salvia farinacea, salvia mexico, salvia greggii and salvia officinalis

Salvia species are used worldwide for medicine purposes. In general, these medicinal plants have high amounts of flavonoids and phenolic acids, that are thought to be closely related to their health properties [1,2]. In this work, the aerial parts of Salvia farinacea, Salvia mexico, Salvia greggii and Salvia officinalis were extracted with hot water [3]. Extracts were evaluated for their total phenolic content by an adaptation of the Folin-Ciocalteu method and further analysed by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative ion mode [4], in order to identify their individual phenolic constituents. The aqueous extracts of S. farinacea, S. mexico, S. officinalis and S. greggii contained, respectively, 106±13, 159±38, 175±46 and 136±1 μg GAE/mg of total phenolics. These four species were characterized by a clear prevalence of caffeic acid derivatives, in particular of rosmarinic acid (MW 360), that is generally the most abundant phenolic compound in Salvia species [2,3]. In addition, S. mexico and S. officinalis contained moderate amounts of salvianolic acid B (MW 718). Among these two, S. mexico was richer in O-caffeoylquinic acid (MW 354), while the latter presented high amounts of salvianolic acid K (MW 556) and moderate amounts of its structural isomer. All the extracts were enriched in flavones: S. farinacea and S. officinalis contained high amounts of luteolin-O-glucuronide while S. mexico contained luteolin-C-glucoside with respective characteristic mass spectrometry fragmentation pattern m/z at 461→285 and m/z at 447→357, 327. Similarly, S. greggii extract presented high content of luteolin-7-O-glucoside ([M-H]− at m/z 447→ 285) and luteolin-C-glucoside and moderate quantities of apigenin-C-hexoside ([M-H]− at m/z 431→341, 311). Further studies are being undertaken in order to understand the contribution of these phenolic constituents in the biological activities of Salvia plants.

Phenolic composition of four sage species: salvia farinacea, salvia mexico, salvia greggii and salvia officinalis

Salvia species are used worldwide for medicine purposes. In general, these medicinal plants have high amounts of flavonoids and phenolic acids, that are thought to be closely related to their health properties [1,2]. In this work, the aerial parts of Salvia farinacea, Salvia mexico, Salvia greggii and Salvia officinalis were extracted with hot water [3]. Extracts were evaluated for their total phenolic content by an adaptation of the Folin-Ciocalteu method and further analysed by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative ion mode [4], in order to identify their individual phenolic constituents. The aqueous extracts of S. farinacea, S. mexico, S. officinalis and S. greggii contained, respectively, 106±13, 159±38, 175±46 and 136±1 μg GAE/mg of total phenolics. These four species were characterized by a clear prevalence of caffeic acid derivatives, in particular of rosmarinic acid (MW 360), that is generally the most abundant phenolic compound in Salvia species [2,3]. In addition, S. mexico and S. officinalis contained moderate amounts of salvianolic acid B (MW 718). Among these two, S. mexico was richer in O-caffeoylquinic acid (MW 354), while the latter presented high amounts of salvianolic acid K (MW 556) and moderate amounts of its structural isomer. All the extracts were enriched in flavones: S. farinacea and S. officinalis contained high amounts of luteolin-O-glucuronide while S. mexico contained luteolin-C-glucoside with respective characteristic mass spectrometry fragmentation pattern m/z at 461→285 and m/z at 447→357, 327. Similarly, S. greggii extract presented high content of luteolin-7-O-glucoside ([M-H]− at m/z 447→ 285) and luteolin-C-glucoside and moderate quantities of apigenin-C-hexoside ([M-H]− at m/z 431→341, 311). Further studies are being undertaken in order to understand the contribution of these phenolic constituents in the biological activities of Salvia plants.

Phenolic compounds and antioxidant capacity of three thymus species plants

Thymus plants comprise distinct species with claimed health properties [1], commonly associated to their essential oils and phenolic compounds. Albeit that, the phenolic composition and the biological activities of many Thymus species remain unclear. This work aimed to elucidate the phenolic composition and antioxidant properties of aqueous extracts from Thymus herba barona, Thymus caespetitus and Thymus fragrantissimus. The aqueous extracts of the three Thymus species were evaluated for their total phenolic compounds by an adaptation of the Folin-Ciocalteu method [2], and individual phenolic compounds were identified by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative mode. The antioxidant activity of each extract was carried out by DPPH● scavenging assay and ferric reducing antioxidant power assays [3]. Total phenolic compounds in the three extracts ranged from 236±27 (T. caespetitus) to 273±17 μg GAE/mg (T. fragrantissimus). Similarly to other Thymus species [1,4], these extracts were rich in caffeic acid derivatives (characteristic UV spectra maxima at 290 and 328 nm) and mainly composed of rosmarinic acid (MW 360). Other caffeic acid derivatives included salvianolic acid K (MW 556) and 3′-O-(8″-Z-caffeoyl)rosmarinic acid (MW 538). High amounts of the flavone luteolin-O-glucuronide ([M-H]− at m/z 461→285) were found in T. caespetitus while the others species contained moderate amounts of this compound. T. herba barona, T. caespetitus and T. fragrantissimus extracts showed high DPPH radical scavenge ability (EC50 values 11.6±0.9, 13.8±0.6 and 10.9±1.2 μg/mL respectively), as well as high reducing power (EC50 values of 35.1±4.5, 39.3±2.7 and 32.4±4.3 μg/mL, respectively), that were comparable to those of reference compounds. This work is an important contribution for the phytochemical characterization and the antioxidant capacity of these three Thymus species.

Phenolic compounds and antioxidant capacity of three thymus species plants

Thymus plants comprise distinct species with claimed health properties [1], commonly associated to their essential oils and phenolic compounds. Albeit that, the phenolic composition and the biological activities of many Thymus species remain unclear. This work aimed to elucidate the phenolic composition and antioxidant properties of aqueous extracts from Thymus herba barona, Thymus caespetitus and Thymus fragrantissimus. The aqueous extracts of the three Thymus species were evaluated for their total phenolic compounds by an adaptation of the Folin-Ciocalteu method [2], and individual phenolic compounds were identified by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative mode. The antioxidant activity of each extract was carried out by DPPH● scavenging assay and ferric reducing antioxidant power assays [3]. Total phenolic compounds in the three extracts ranged from 236±27 (T. caespetitus) to 273±17 μg GAE/mg (T. fragrantissimus). Similarly to other Thymus species [1,4], these extracts were rich in caffeic acid derivatives (characteristic UV spectra maxima at 290 and 328 nm) and mainly composed of rosmarinic acid (MW 360). Other caffeic acid derivatives included salvianolic acid K (MW 556) and 3′-O-(8″-Z-caffeoyl)rosmarinic acid (MW 538). High amounts of the flavone luteolin-O-glucuronide ([M-H]− at m/z 461→285) were found in T. caespetitus while the others species contained moderate amounts of this compound. T. herba barona, T. caespetitus and T. fragrantissimus extracts showed high DPPH radical scavenge ability (EC50 values 11.6±0.9, 13.8±0.6 and 10.9±1.2 μg/mL respectively), as well as high reducing power (EC50 values of 35.1±4.5, 39.3±2.7 and 32.4±4.3 μg/mL, respectively), that were comparable to those of reference compounds. This work is an important contribution for the phytochemical characterization and the antioxidant capacity of these three Thymus species.

Antifungal activity of extracts from Atacama Desert fungi against Paracoccidioides brasiliensis and identification of Aspergillus felis as a promising source of natural bioactive compounds

Fungi of the genus Paracoccidioides are responsible for paracoccidioidomycosis. The occurrence of drug toxicity and relapse in this disease justify the development of new antifungal agents. Compounds extracted from fungal extract have showing antifungal activity. Extracts of 78 fungi isolated from rocks of the Atacama Desert were tested in a microdilution assay against Paracoccidioides brasiliensis Pb18. Approximately 18% (5) of the extracts showed minimum inhibitory concentration (MIC) values ≤ 125.0 μg/mL. Among these, extract from the fungus UFMGCB 8030 demonstrated the best results, with an MIC of 15.6 μg/mL. This isolate was identified as Aspergillus felis (by macro and micromorphologies, and internal transcribed spacer, β-tubulin, and ribosomal polymerase II gene analyses) and was grown in five different culture media and extracted with various solvents to optimise its antifungal activity. Potato dextrose agar culture and dichloromethane extraction resulted in an MIC of 1.9 μg/mL against P. brasiliensis and did not show cytotoxicity at the concentrations tested in normal mammalian cell (Vero). This extract was subjected to bioassay-guided fractionation using analytical C18RP-high-performance liquid chromatography (HPLC) and an antifungal assay using P. brasiliensis. Analysis of the active fractions by HPLC-high resolution mass spectrometry allowed us to identify the antifungal agents present in the A. felis extracts cytochalasins. These results reveal the potential of A. felis as a producer of bioactive compounds with antifungal activity.

Liquid chromatographic-mass spectrometric method for determination of drug content uniformity of two commonly used dermatology medications in a split-tablet dosage form

Purpose: To develop and validate a simple, efficient and reliable Liquid chromatographic-mass spectrometric (LC-MS/MS) method for the quantitative determination of two dermatological drugs, Lamisil® (terbinafine) and Proscar® (finasteride), in split tablet dosage form. Methods: Thirty tablets each of the 2 studied medications were randomly selected. Tablets were weighed and divided into 3 groups. Ten tablets of each drug were kept intact, another group of 10 tablets were manually split into halves using a tablet cutter and weighed with an analytical balance; a third group were split into quarters and weighed. All intact and split tablets were individually dissolved in a water: methanol mixture (4:1), sonicated, filtered and further diluted with mobile phase. Optimal chromatographic separation and mass spectrometric detection were achieved using an Agilent 1200 HPLC system coupled with an Agilent 6410 triple quadrupole mass spectrometer. Analytes were eluted through an Agilent eclipse plus C8 analytical column (150 mm × 4.6 mm, 5 μm) with a mobile phase composed of solvent A (water) containing 0.1% formic acid and 5mM ammonium formate pH 7.5, and solvent B (acetonitrile mixed with water in a ratio A:B 55:45) at a flow rate of 0.8 mL min-1 with a total run time of 12 min. Mass spectrometric detection was carried out using positive ionization mode with analyte quantitation monitored by multiple reaction monitoring (MRM) mode. Results: The proposed analytical method proved to be specific, robust and adequately sensitive. The results showed a good linear fit over the concentration range of 20 - 100 ng mL-1 for both analytes, with a correlation coefficient (r2) ≥ 0.999 and 0.998 for finasteride and terbinafine, respectively. Following tablet splitting, the drug content of the split tablets fell outside of the proxy USP specification for at least 14 halves (70 %) and 34 quarters (85 %) of FIN, as well as 16 halves (80 %) and 37 quarters (92.5 %) of TBN. Mean weight loss, after splitting, was 0.58 and 2.22 % for FIN half- and quarter tablets, respectively, and 3.96 and 4.09 % for TBN half- and quarter tablets,respectively. Conclusion: The proposed LC-MS/MS method has successfully been used to provide precise drug content uniformity of split tablets of FIN and TBN. Unequal distribution of the drug on the split tablets is indicated by the high standard deviation beyond the accepted value. Hence, it is recommended not to split non-scored tablets especially, for those medications with significant toxicity

Chemical Reaction Dynamics of the Liquid/Vapor Interface Studied by Mass Spectrometry

This thesis presents investigations of chemical reactions occurring at the liquid/vapor interface studied using novel sampling methodologies coupled with detection by mass spectrometry. Chapters 2 and 3 utilize the recently developed technique of field-induced droplet ionization mass spectrometry (FIDI-MS), in which the application of a strong electric field to a pendant microliter droplet results in the ejection of highly charged progeny droplets from the liquid surface. In Chapter 2, this method is employed to study the base-catalyzed dissociation of a surfactant molecule at the liquid/vapor interface upon uptake of ammonia from the gas phase. This process is observed to occur without significant modulation of the bulk solution pH, suggesting a transient increase in surface pH following the uptake of gaseous ammonia. Chapter 3 presents real-time studies of the oxidation of the model tropospheric organic compound glycolaldehyde by photodissociation of iron (III) oxalate complexes. The oxidation products of glycolaldehyde formed in this process are identified, and experiments in a deoxygenated environment identify the role of oxygen in the oxidation pathway and in the regeneration of iron (III) following photo-initiated reduction. Chapter 4 explores alternative methods for the study of heterogeneous reaction processes by mass spectrometric sampling from liquid surfaces. Bursting bubble ionization (BBI) and interfacial sampling with an acoustic transducer (ISAT) generate nanoliter droplets from a liquid surface that can be sampled via the atmospheric pressure interface of a mass spectrometer. Experiments on the oxidation of oleic acid by ozone using ISAT are also presented. Chapters 5 and 6 detail mechanistic studies and applications of free-radical-initiated peptide sequencing (FRIPS), a technique employing gas-phase free radical chemistry to the sequencing of peptides and proteins by mass spectrometry. Chapter 5 presents experimental and theoretical studies on the anomalous mechanism of dissociation observed in the presence of serine and threonine residues in peptides. Chapter 6 demonstrates the combination of FRIPS with ion mobility-mass spectrometry (IM-MS) for the separation of isomeric peptides.

Androgen levels increase by intratumoral de novo steroidogenesis during progression of castration-resistant prostate cancer

Although systemic androgen deprivation prolongs life in advanced prostate cancer, remissions are temporary because patients almost uniformly progress to a state of a castration-resistant prostate cancer (CRPC) as indicated by recurring PSA. This complex process of progression does not seem to be stochastic as the timing and phenotype are highly predictable, including the observation that most androgen-regulated genes are reactivated despite castrate levels of serum androgens. Recent evidence indicates that intraprostatic levels of androgens remain moderately high following systemic androgen deprivation therapy, whereas the androgen receptor (AR) remains functional, and silencing the AR expression following castration suppresses tumor growth and blocks the expression of genes known to be regulated by androgens. From these observations, we hypothesized that CRPC progression is not independent of androgen-driven activity and that androgens may be synthesized de novo in CRPC tumors leading to AR activation. Using the LNCaP xenograft model, we showed that tumor androgens increase during CRPC progression in correlation to PSA up-regulation. We show here that all enzymes necessary for androgen synthesis are expressed in prostate cancer tumors and some seem to be up-regulated during CRPC progression. Using an ex vivo radiotracing assays coupled to high-performance liquid chromatography-radiometric/mass spectrometry detection, we show that tumor explants isolated from CRPC progression are capable of de novo conversion of [(14)C]acetic acid to dihydrotestosterone and uptake of [(3)H]progesterone allows detection of the production of six other steroids upstream of dihydrotestosterone. This evidence suggests that de novo androgen synthesis may be a driving mechanism leading to CRPC progression following castration.

Comparison of the binding stoichiometries of positively charged DNA-binding drugs using positive and negative ion electrospray ionization mass spectrometry

Positive and negative ion electrospray ionization (ESI) mass spectra of complexes of positively charged small molecules (distamycin, Hoechst 33258, [Ru(phen)2dpq]Cl2 and [Ru(phen)2dpqC]Cl2) have been compared. [Ru(phen)2dpq]Cl2 and [Ru(phen)2dpqC]Cl2 bind to DNA by intercalation. Negative ion ESI mass spectra of mixtures of [Ru(phen)2dpq]Cl2 or [Ru(phen)2dpqC]Cl2 with DNA showed ions from DNA-ligand complexes consistent with solution studies. In contrast, only ions from freeDNAwere present in positive ion ESI mass spectra of mixtures of [Ru(phen)2dpq]Cl2 or [Ru(phen)2dpqC]Cl2 with DNA, highlighting the need for obtaining ESI mass spectra of non-covalent complexes under a range of experimental conditions. Negative ion spectra of mixtures of the minor groove binder Hoechst 33258 with DNA containing a known minor groove binding sequence were dominated by ions from a 1:1 complex. In contrast, in positive ion spectra there were also ions present from a 2:1 (Hoechst 33258: DNA) complex, suggesting an alternative binding mode was possible either in solution or in the gas phase. When Hoechst 33258 was mixed with a DNA sequence lacking a high affinity minor groove binding site, the negative ion ESI mass spectra showed that 1:1 and 2:1 complexes were formed, consistent with existence of binding modes other than minor groove binding. The data presented suggest that comparison of positive and negative ion ESI-MS spectra might provide an insight into various binding modes in both solution and the gas phase.

Pharmacokinetics of isofraxidin in rat plasma after oral administration of the extract of acanthopanax senticosus using HPLC with solid phase extraction method

High-performance liquid chromatography coupled with solid phase extraction method was developed for determination of isofraxidin in rat plasma after oral administration of Acanthopanax senticosus extract (ASE), and pharmacokinetic parameters of isofraxidin either in ASE or pure compound were measured. The HPLC analysis was performed on a Dikma Diamonsil RP(18) column (4.6 mm x 150 mm, 5 microm) with the isocratic elution of solvent A (acetonitrile) and solvent B (0.1% aqueous phosphoric acid, v/v) (A : B = 22 : 78) and the detection wavelength was set at 343 nm. The calibration curve was linear over the range of 0.156-15.625 microg/ml. The limit of detection was 60 ng/ml. The intra-day precision was 5.8%, and the inter-day precision was 6.0%. The recovery was 87.30+/-1.73%. When the dosage of ASE is equal to pure compound caculated by the amount of isofraxidin, it has been found to have two maximum concentrations in plasma while the pure compound only showed one peak in the plasma concentration-time curve. The determined content of isofraxidin in plasma after oral administration of ASE is the total contents of free isofraxidin and its precursors in ASE in vitro. The pharmacokinetic characteristics of ASE showed the priority of the extract and the properities of traditional Chinese medicine.

Automated surface sampling of lipids from worn contact lenses coupled with tandem mass spectrometry

The deposition of biological material (biofouling) onto polymeric contact lenses is thought to be a major contributor to lens discomfort and hence discontinuation of wear. We describe a method to characterize lipid deposits directly from worn contact lenses utilizing liquid extraction surface analysis coupled to tandem mass spectrometry (LESA-MS/MS). This technique effected facile and reproducible extraction of lipids from the contact lens surfaces and identified lipid molecular species representing all major classes present in human tear film. Our data show that LESA-MS/MS is a rapid and comprehensive technique for the characterization of lipid-related biofouling on polymer surfaces.

Desorption electrospray ionisation mass spectrometry of stabilised polyesters reveals activation of hindered amine light stabilisers

The use of hindered amine light stabilizers (HALS) to retard thermo- and photo-degradation of polymers has become increasingly common. Proposed mechanisms of polymer stabilisation involve significant changes to the HALS chemical structure; however, reports of the characterisation of these modified chemical species are limited. To better understand the fate of HALS and determine their in situ modifications, desorption electrospray ionisation mass spectrometry (DESI-MS) was employed to characterise ten commercially available HALS present in polyester-based coil coatings. TINUVIN® 770, 292, 144, 123, 152, and NOR371; HOSTAVIN® 3052, 3055, 3050, and 3058 were separately formulated with a pigmented, thermosetting polyester resin, cured on metal at 262 C and analysed directly by DESI-MS. High-level ab initio molecular orbital theory calculations were also undertaken to aid the mechanistic interpretation of the results. For HALS containing N-substituted piperidines (i.e., N-CH3, N-C(O)CH3, and N-OR) a secondary piperidine (N-H) analogue was detected in all cases. The formation of these intermediates can be explained either through hydrogen abstraction based mechanisms or direct N-OR homolysis with the former dominant under normal service temperatures (ca. 25-80 C), and the latter potentially becoming competitive under the high temperatures associated with curing (ca. 230-260 C). © 2013 Elsevier Ltd. All rights reserved.

Hydrolysis of triasulfuron, metsulfuron-methyl and chlorsulfuron in alkaline soil and aqueous solutions

The hydrolysis of triasulfuron, metsulfuron-methyl and chlorsulfuron in aqueous buffer solutions and in soil suspensions at pH values ranging from 5.2 to 11.2 was investigated. Hydrolysis of all three compounds in both aqueous buffer and soil suspensions was highly pH-sensitive. The rate of hydrolysis was much faster in the acidic pH range (5.2-6.2) than under neutral and moderately alkaline conditions (8.2-9.4), but it increased rapidly as the pH exceeded 10.2. All three compounds degraded faster at pH 5.2 than at pH 11.2. Hydrolysis rates of all three compounds could be described well with pseudo-first-order kinetics. There were no significant differences (P =0.05) in the rate constants (k, day-1) of the three compounds in soil suspensions from those in buffer solutions within the pH ranges studied. A functional relationship based on the propensity of nonionic and anionic species of the herbicides to hydrolyse was used to describe the dependence of the 'rate constant' on pH. The hydrolysis involving attack by neutral water was at least 100-fold faster when the sulfonylurea herbicides were undissociated (acidic conditions) than when they were present as the anion at near neutral pH. In aqueous buffer solution at pH > 11, a prominent degradation pathway involved O-demethylation of metsulfuron-methyl to yield a highly polar degradate, and hydrolytic opening of the triazine ring. It is concluded that these herbicides are not likely to degrade substantially through hydrolysis in most agricultural (C) 2000 Society of Chemical Industry.