Standard Reference Compounds Research Articles

Mass spectrometry guided strategy based on feature fragment ions for guided-separation on quinoline alkaloids from root barks of Dictamnus dasycarpus

The root bark of Dictamnus dasycarpus is one of common traditional Chinese medicines (TCMs). Quinoline alkaloids are one of the main active substances in this TCM and possess many biological activities including anti-titumor, anti-inflammation, anti-bacteria, anti-oxidation, and anti-platelet aggregation activities. In this study, eight quinoline alkaloids 1-8 were firstly separated from the root barks of D. dasycarpus. It was difficult to isolate more quinoline alkaloids from the remaining fraction 8 in D. dasycarpus by this conventional chemical separation, so the target analysis method combined LC-MS guided-separation of quinoline alkaloids from fraction 8 was established. MS/MS fragmentation patterns of eight quinoline alkaloids reference standard compounds 1-8 were studied by ultra-performance liquid chromatography-electrospary ionization-mass spectrometry (UPLC-ESI-MS/MS). Based on the feature fragment ion m/z 200, the parent ion scan mode was established for the target analysis of quinoline alkaloids in fraction 8. Finally, 8-methoxyflindersine (9) and N-metilatanina (10) were discovered and isolated quickly from fraction 8 guided by LC-MS, and their structures were identified by NMR and MS. Among them, compound 10 was isolated from the genus Dictamnus for the first time. These results indicated that this method is not only quick and sensitive for analyzing the quinoline alkaloids, but also to effectively guided-separate this kind of alkaloids in the root barks of D. dasycarpus.

Membrane Fatty Acid Composition and Cell Surface Hydrophobicity of Marine Hydrocarbonoclastic Alcanivorax borkumensis SK2 Grown on Diesel, Biodiesel and Rapeseed Oil as Carbon Sources.

The marine hydrocarbonoclastic bacterium Alcanivorax borkumensis is well known for its ability to successfully degrade various mixtures of n-alkanes occurring in marine oil spills. For effective growth on these compounds, the bacteria possess the unique capability not only to incorporate but also to modify fatty intermediates derived from the alkane degradation pathway. High efficiency of both these processes provides better competitiveness for a single bacteria species among hydrocarbon degraders. To examine the efficiency of A. borkumensis to cope with different sources of fatty acid intermediates, we studied the growth rates and membrane fatty acid patterns of this bacterium cultivated on diesel, biodiesel and rapeseed oil as carbon and energy source. Obtained results revealed significant differences in both parameters depending on growth substrate. Highest growth rates were observed with biodiesel, while growth rates on rapeseed oil and diesel were lower than on the standard reference compound (hexadecane). The most remarkable observation is that cells grown on rapeseed oil, biodiesel, and diesel showed significant amounts of the two polyunsaturated fatty acids linoleic acid and linolenic acid in their membrane. By direct incorporation of these external fatty acids, the bacteria save energy allowing them to degrade those pollutants in a more efficient way. Such fast adaptation may increase resilience of A. borkumensis and allow them to strive and maintain populations in more complex hydrocarbon degrading microbial communities.

Coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) to fingerprint soil organic matter bulk chemistry

A novel method coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) was developed to characterize soil organic matter (SOM) chemistry in soils. The pyrolyzer was interfaced to the MIR spectrometer by means of a Brill cell™ (CDS Analytica). The set-up generates pyrolysis fingerprint spectra from which individual pyrolysis products can be related to SOM bulk chemistry. Py-MIRS development involved the testing of experimental conditions like pyrolysis temperature (550, 700, 1000 °C), heating rate (20 °C s−1 and 20 °C ms−1) and time (15, 30 and 60 s) using reference standard compounds ranging from carbohydrates to phenols varying in chemical and structural composition like levoglusogan, gluten, tannin, syringol, pectin and leucine falling within different compound categories (carbohydrates, amino acids, proteins, phenols, etc.) as well as soil samples. Pyrolysis yields of prominent specific functional groups, like aliphatics (CH stretching at 2930 cm−1) and CC aromatics (1510 cm−1), varied with pyrolysis temperature, heating rate and time. The preferred settings for high pyrolysis yield and minimized secondary reactions were obtained at a pyrolysis temperature of 700 °C, heating rate of 20 °C ms−1 and heating time of 30 s. The suitability of Py-MIRS to detect changes in SOM composition was evaluated by comparing Py-MIRS results to Diffuse Reflectance Fourier Transform mid-Infrared Spectroscopy (DRIFTS) results. Soil samples taken from the Static Fertilization Experiment, Bad Lauchstädt, Germany (Chernozem) revealed a major SOM contribution of the peak at 1750 cm−1 (CO), followed by peaks at 950 (CH), 1510 (CC), 1176 (CH, OH) cm−1, with smaller contributions from the 2930 (CH) and 3015 (CH4) cm−1 peaks, apart from a dominant CO2 peak. Using the preferred pyrolysis settings, Py-MIRS as well as DRIFTS results further indicated that soils receiving organic (e.g. farmyard manure) inputs were highly enriched in aliphatic groups, while their absence favored the accumulation of carboxyl and aromatic groups as well as polysaccharides. Py-MIRS allowed via semi-quantification of pyrolysis products a rapid monitoring of SOM bulk chemistry with a high degree of reproducibility. It was concluded that Py-MIRS represents a fast, effective and reproducible technique to characterize changes in the SOM bulk chemistry as a result of management practices. It also allows to minimize acknowledged constraints of other analytical techniques used to characterize SOM bulk chemistry such as mineral interferences and associated secondary reactions.

Plant-Derived Anticancer Agents: Lessons from the Pharmacology of Geniposide and Its Aglycone, Genipin.

For centuries, plants have been exploited by mankind as sources of numerous cancer chemotherapeutic agents. Good examples of anticancer compounds of clinical significance today include the taxanes (e.g., taxol), vincristine, vinblastine, and the podophyllotoxin analogues that all trace their origin to higher plants. While all these drugs, along with the various other available therapeutic options, brought some relief in cancer management, a real breakthrough or cure has not yet been achieved. This critical review is a reflection on the lessons learnt from decades of research on the iridoid glycoside geniposide and its aglycone, genipin, which are currently used as gold standard reference compounds in cancer studies. Their effects on tumour development (carcinogenesis), cancer cell survival, and death, with particular emphasis on their mechanisms of actions, are discussed. Particular attention is also given to mechanisms related to the dual pro-oxidant and antioxidant effects of these compounds, the mitochondrial mechanism of cancer cell killing through reactive oxygen species (ROS), including that generated through the uncoupling protein-2 (UCP-2), the inflammatory mechanism, and cell cycle regulation. The implications of various studies for the evaluation of glycosidic and aglycone forms of natural products in vitro and in vivo through pharmacokinetic scrutiny are also addressed.

Incorporating terpenes, monoterpenoids and alkanes into multiresidue organic biomarker analysis of archaeological stone artefacts from Liang Bua (Flores, Indonesia)

A sensitive and selective gas chromatography-tandem mass spectrometry (GC–MS/MS) method for the detection and quantification of terpenes, monoterpenoids and alkanes was developed and validated, to complement an existing analytical workflow set up for organic biomarker analysis of stone artefacts. This method was applied to seven stone artefacts—six of which contained potential use-residues based on a previous study using non-volatile low molecular weight lipid biomarkers—recovered from Liang Bua, an archaeological cave site on the Indonesian island of Flores. Following localised solvent extractions of the artefacts, aliquots of the solvent extracts were directly assayed using the optimised method. Identification of an analyte was considered positive when three criteria were met: (1) the retention time was the same as observed for a reference standard; (2) the three selected multiple reaction monitoring transitions for a reference standard compound were observed for the analyte; and (3) the qualitative ions (relative to the quantitative ion) were present in the expected ratios consistent with the reference standard. Alkane chemical profiles indicated that the presence of plant residues cannot be excluded, but of particular interest was the detection of camphor on one of the artefacts. Camphor-containing plants are found throughout Asia, including Indonesia, and are known historically to have been used for medicinal and culinary purposes. The likelihood of resource processing was high for three of the artefacts, and medium for the remaining four artefacts, based on the specificity, quantity and combination of the analytes identified.

A method for dyeing polyester fibres with quinone derivatives and evaluation of their antioxidant activity

In this study, a series of bis(thio)substituted-1,4-naphthoquinone compounds (4a-j) were synthesized via Michael addition reaction and their structures were determined by infrared spectrometry, 1H and 13C nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. The synthesized substances were applied to polyester fibers and the dyeing properties were investigated. The rubbing fastness, wash fastness and optical properties of synthesized compounds were also studied. The color change and staining test results were found to be ?4? to ?4-5? for the most of the dyed samples. There is only a small number of previous studies interested with dyeing properties of synthetic derivatives of heteroatom-substituted-1,4-naphthoquinone compounds in existing literature. The synthesized dyes were screened for their antioxidant activity, using the CUPRAC method against trolox (TR) as the standard reference compound at room temperature. The aims of this study were the synthesis of the quinone compounds, the investigation of the capability of dyeing polyester fibers and the evaluation of their antioxidant capacity, using the CUPRAC method. The dyed polyester fibers are promising candidates for biologically active fabrics to be used in various ways. We were encouraged to do this study in order to determine the dying properties and antioxidant activities of the quinone compounds.

Computational Studies Applied to Flavonoids against Alzheimer's and Parkinson's Diseases.

Neurodegenerative diseases, such as Parkinson's and Alzheimer's, are understood as occurring through genetic, cellular, and multifactor pathophysiological mechanisms. Several natural products such as flavonoids have been reported in the literature for having the capacity to cross the blood-brain barrier and slow the progression of such diseases. The present article reports on in silico enzymatic target studies and natural products as inhibitors for the treatment of Parkinson's and Alzheimer's diseases. In this study we evaluated 39 flavonoids using prediction of molecular properties and in silico docking studies, while comparing against 7 standard reference compounds: 4 for Parkinson's and 3 for Alzheimer's. Osiris analysis revealed that most of the flavonoids presented no toxicity and good absorption parameters. The Parkinson's docking results using selected flavonoids as compared to the standards with four proteins revealed similar binding energies, indicating that the compounds 8-prenylnaringenin, europinidin, epicatechin gallate, homoeriodictyol, capensinidin, and rosinidin are potential leads with the necessary pharmacological and structural properties to be drug candidates. The Alzheimer's docking results suggested that seven of the 39 flavonoids studied, being those with the best molecular docking results, presenting no toxicity risks, and having good absorption rates (8-prenylnaringenin, europinidin, epicatechin gallate, homoeriodictyol, aspalathin, butin, and norartocarpetin) for the targets analyzed, are the flavonoids which possess the most adequate pharmacological profiles.

In vitro assessment of sex steroids and related compounds in water and sediments - a critical review.

Detection of endocrine disrupting compounds in water and sediment samples has gained much importance since the evidence of their effects was reported in aquatic ecosystems in the 1990s. The aim of this review is to highlight the advances made in the field of in vitro analysis for the detection of hormonally active compounds with estrogenic, androgenic and progestogenic effects in water and sediment samples. In vitro assays have been developed from yeast, mammalian and in a few cases from fish cells. These assays are based either on the hormone-mediated proliferation of sensitive cell lines or on the hormone-mediated expression of reporter genes. In vitro assays in combination with various sample enrichment methods have been used with limits of detection as low as 0.0027 ng L-1 in water, and 0.0026 ng g-1 in sediments for estrogenicity, 0.1 ng L-1 in water, and 0.5 ng g-1 in sediments for androgenicity, and 5 ng L-1 in water for progestogenicity expressed as equivalent concentrations of standard reference compounds of 17β-estradiol, dihydrotestosterone and progesterone, respectively. The experimental results and limits of quantification, however, are influenced by the methods of sample collection, preparation, and individual laboratory practices.

Chromatographic and in silico assessment of logP measures for new spirohydantoin derivatives with anticancer activity

AbstractLipophilicity has, for a long time, been recognized as a meaningful parameter in structure‐activity relationships. It is also the single most informative physicochemical property that reveals a wealth of information on intermolecular forces, intramolecular interactions, and molecular structure in the broadest sense. In this paper, a total of 14 chromatographic measures of lipophilicity (thin‐layer chromatography and high‐performance liquid chromatography) and 11 computationally estimated logP‐s for 21 newly synthesized 3‐(4‐substituted benzyl)‐cycloalkylspiro‐5‐hidantoin derivatives have been investigated. Similarities among the investigated compounds as well as lipophilicity measures were examined by the multivariate exploratory analysis, principal component analysis, hierarchical cluster analysis, and sum of ranking differences. These chemometric approaches reveal the arrangement of investigated compounds into clusters according to lipophilicity. Chemometric consideration of lipophilicity renders principal component scores as entirely unsuitable lipophilicity measures. Furthermore, the logP values estimated from calibration graph by using a set of standard reference compounds were equivalent to the corresponding chromatographic descriptors of hydantoins extrapolated from linear relationship between retention parameters and mobile phase composition. Comparison of the 2 chromatographic techniques places high‐performance liquid chromatography lipophilicity indices slightly ahead of thin‐layer chromatography.

Deciphering the chemical origin of the semen-like floral scents in three angiosperm plants

The chemical origin and biological role of distinct semen-like odor occasionally found in some flowers are very curious but remain scarcely studied. Here, we used direct ambient corona discharge ionization mass spectrometry (MS) to study the volatile chemical composition behind the semen-like odor emitted by the fresh flowers of Photinia serrulata, Castanopsis sclerophylla and Stemona japonica without any chemical pretreatment. Chemical identification was performed using high-resolution MS analysis in combination with tandem MS analysis and whenever possible was confirmed by the analysis of standard reference compounds. A total of 19 compounds, mostly belonging to nitrogenous volatiles, were identified in P. serrulata, C. sclerophylla, and S. japonica flowers, 1-pyrroline, 1-piperideine, 2-pyrrolidone, and phenethylamine being common in all the three studied species. Several lines of evidence indicate that the major component responsible for the semen-like odor is most likely 1-pyrroline. 1-Pyrroline is most probably formed via the oxidative deamination of putrescine, as indicated by the observation of signal from 4-amino-butanal intermediate. Flower visitation observations suggest that the released volatiles serve to attract dipterans, including Syrphidae, Calliphoridae, and Muscidae. On the analytical side, the comparison of our results to earlier studies also indicate that compared to the traditional GC-MS approach the direct corona discharge ionization mass spectrometry provides more sensitive detection of VOCs with high proton affinity, in particular volatile amines, and therefore can be used to complement traditional GC-MS approach for the highest chemical coverage of VOC analysis.

Fungi as a source of marker compounds for the control of illicit use of drugs: mesterolone as a case study

Anabolic steroids are frequently misused for performance enhancement during sports competitions. One of the major bottlenecks in the confident analysis of steroids and their metabolites is the non-availability/cost of standard reference compounds. The study objective was to identify the common metabolites of prohibited anabolic steroids that are produced in both fungi and human and thus can be synthesized in bulk using fungal cultures. Mesterolone is used as a case study. The study was conducted in three steps; we first studied the fungal transformation of mesterolone. In the second step, these metabolites were used as references to detect in human urine after the oral use of mesterolone using LC-ESI-QqQ-MS/MS. In the third step, 12 fungal cultures were screened to evaluate their potential to produce reference markers. This led to the detection of two metabolites, 6α-hydroxymesterolone (M1) and 7α-hydroxymesterolone (M2) that were found to be common in both, fungal cultures and human urine samples. Moreover, Rhizopus stolonifer and Beauveria bassiana can be considered as good candidates to produce M1 and M2 metabolites, respectively. This approach can be employed for the synthesis of marker compounds of other prohibited anabolic steroids thus can be detected efficiently during national and international sports competitions.

In vitro propagation, genetic stability, and secondary metabolite analysis of wild lavender (Lavandula coronopifolia Poir.)

Lavenders (Lavandula species) are important aromatic ornamental medicinal plants with wide ranging applications in perfume and pharmaceutical industries. We developed an in vitro propagation protocol for Lavandula coronopifolia. Murashige and Skoog (MS) medium supplemented with 0.5 mg·L-1 N 6 -benzyladenine was the best medium for the proliferation of microshoots, while the highest rooting frequency was obtained using MS medium supplemented with 1.0 mg·L-1 indole-3-butyric acid. Inter-simple sequence repeat analysis revealed that the in vitro-propagated microshoots were highly genetically stable, even after subculture. The highest callus fresh weight (667.9 mg) was obtained by propagating on medium supplemented with a combination of 1.0 mg·L-1 naphthaleneacetic acid and 0.5 mg·L-1 butyric acid. Using the Folin-Ciocalteu method, methanolic extracts of wild L. coronopifolia revealed total phenolic content of 4.9 mg expressed in gallic acid equivalents (GAE) (mg GAE·g-1 dry matter). Radical scavenging activity was estimated at 85% using the free radical 2,2-diphyenyl-picrylhydrazyl assay. Using the brine shrimp assay for cytotoxicity, the methanolic extract was found to be nontoxic. Finally, liquid chromatography tandem mass spectrometry with standard reference compounds was used to quantify the key phenolic compounds in both in vitro and in vivo-grown L. coronopifolia. Six major phenolic compounds were identified: caffeic acid, rosmarinic acid, rutin, quercetin, luteolin, and hesperidin. Levels of these phenolic compounds were highest in wild plant extracts.

Chemical characterization and antioxidant potential of volatile oil from an edible seaweed Porphyra tenera (Kjellman, 1897)

BackgroundPorphyra tenera (Kjellman, 1897) is the most common eatable red seaweed in Asia. In the present study, P. tenera volatile oil (PTVO) was extracted from dried P. tenera sheets that were used as food by the microwave hydrodistillation procedure, after which the characterization of its chemical constituents was done by gas chromatography and mass spectroscopy and its antioxidant potential was evaluated by a number of in vitro biochemical assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, nitric oxide (NO) scavenging, superoxide radical scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, hydroxyl radical scavenging and reducing power assay and inhibition of lipid peroxidation.ResultsA total of 30 volatile compounds comprising about 99.4% of the total volume were identified, of which trans-beta-ionone (20.9%), hexadecanoic acid (9.2%) and 2,6-nonadienal (8.7%) were present in higher quantities. PTVO exhibited strong free radical scavenging activity by DPPH scavenging (44.62%), NO scavenging (28.45%) and superoxide scavenging (54.27%) at 500 µg/mL. Similarly, it displayed strong ABTS radical scavenging (IC50 value of 177.83 µg/mL), hydroxyl radical scavenging (IC50 value of 109.70 µg/mL), and moderate lipid peroxidation inhibition activity (IC50 value of 231.80 µg/mL) and reducing power (IC0.5 value of 126.58 µg/mL). PTVO exhibited strong antioxidant potential in a concentration dependent manner and the results were comparable with the BHT and α-tocopherol, taken as the reference standard compounds (positive controls).ConclusionsTaken together, PTVO with potential bioactive chemical compounds and strong antioxidant activity could be utilized in the cosmetic industries for making antioxidant rich anti-aging and sun-screen lotion and in the food sector industries as food additives and preservatives.

UHPLC-ESI-qTOF-MS Analysis of Cyclopeptide Alkaloids in the Seeds of Ziziphus jujuba var. spinosa

An UHPLC-ESI-qTOF-MS analytical method was developed for cyclopeptide alkaloids in the seeds of Ziziphus jujuba var. spinosa (Semen Ziziphi Spinosae), which is a commonly used herb in Chinese and Korean traditional medicines. Considering the basicity of cyclopeptide alkaloids, a specific separation method was developed for an UHPLC system. The compounds were detected by DAD and ESI-qTOF-MS, and their fragmentation patterns were also acquired by MSE technologies. Peak-picking of major compounds was performed with nine previously isolated compounds and two reference standard compounds. Tandem MS fragmentation behaviors of type-Ia and -Ib cyclopeptide alkaloids were investigated with the acquired data to develop a strategy for dereplication of other cyclopeptide alkaloid compounds in Z. jujuba var. spinosa. Two more cyclopeptide alkaloids were tentatively identified with UHPLC–ESI-qTOF-MS using this method.

Molecular structure studies of novel bronchodilatory-active 4-azafluorenes

Abstract Two 5H-indeno[1,2-b]pyridines, 7a and 7b, were synthesized and characterized by X-ray crystallography. In the molecular packing, molecules of 7a are linked into chains by C–H···N hydrogen bond which, in turn, are connected by H···π, N···π, Cl···π and π···π interactions. In the crystal structure of 7b, molecules are connected by C–H···N and C–H···Cl interactions as well as a set of N···π and Cl···π interactions. The molecular structures were studied by theory using AM1, PM3 and DFT. The basic difference between the theoretical and experimental structures was found in the relative orientation of dichlorophenyl ring attached to the indenopyridine residue, which was revealed to be aligned in nearly opposite orientations. This observation is attributed to the bulky chlorine atom(s) of the phenyl ring that prevent free rotation around the sigma bond attaching this ring with the heterocyclic system. DFT was used to determine the molecular electrostatic potential revealing the nitrile nitrogen to be the most nucleophilic site. A low HOMO-LUMO energy gap indicates high reactivity of 7a and 7b. The synthesized azafluorenes show more potent bronchodilation properties than the standard reference compound (theophylline).

Impedance and Combined Extracellular Field Potential Recordings of CiPA Reference Compounds on IPS Cardiomyocytes

Drug induced arrhythmia is one of the most common causes of drug development failure. Human induced pluripotent stem cell-derived cardiomyocytes (iPSCMs) show great promise for cardiovascular research and predictive in-vitro cardiac safety screening.We present data recorded on the CardioExcyte 96, a hybrid screening instrument that combines impedance (cell contractility) with MEA-like extracellular field potential (EFP) recordings. A case study showing impaired excitation-contraction coupling will be presented. This indicates the importance of testing compounds in assays complementary to patch clamp electrophysiology to provide a more complete safety profile. Furthermore, in accordance with the Comprehensive In Vitro Proarrhythmia Assay (CiPA) guidelines, standard reference compounds were tested on iPS-derived cardiomyocytes. Changes in the impedance signal indicate effects on cell contractility and shape whereas the field potential parameters provide information about the electrophysiological activity of the beating network of cells. Pharmacological effects of a number of reference compounds including those designated high risk (e.g. Dofetilide), intermediate risk (e.g. Cisapride) or low risk (e.g. Verapamil) were evaluated and summarized in this study.The CardioExcyte 96 system provides a non-invasive, label-free, high temporal resolution approach for safety screening. It can be either used in an incubator or, by utilizing the dedicated incubation system, directly on a lab bench. Furthermore, the system is capable of electrically pacing the cells, which allows for screening of cells which beat with individual frequencies and, in addition, investigations of frequency dependent compound inhibition.

Synthesis, Characterization andin vitroAntioxidant Activity of New ChiralN-boc Organotellurium Compounds, (CH3)3OC(O)NHCH(R)C(O)NHCH2-CH2Te-C6H4-4-OCH3, Containing Carbamate and Peptide Groups

Synthesis, characterization and antioxidant activity of a new series of chiral N-boc oraganotellurium compounds, (CH3)3OC(O)NHCH(R)C(O)NHCH2CH2Te-C6H4-4-OCH3, containing carbamate and peptide groups have been reported in this paper. These chiral peptides were synthesized in good to excellent yields, via acid-amine coupling reaction of N-boc L-amino acids with 2-(4-methoxyphenyltelluro) ethylamine in presence of dicyclohexyl carbodimide (DCC) at room temperature. The elemental analyses, Fourier transform infrared (FTIR), 1H and 13C {1H} nuclear magnetic resonance (NMR) spectra and mass spectra were characteristic. Specific optical rotation (SOR) was also determined. In vitro antioxidant activity of these multi-functional compounds in methanol has been evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals with 2,6-di-tert-butyl-4-methylphenol (BHT) as a standard reference compound. The IC50 (inhibitory concentration 50) values of these chiral peptides revealed significant inhibition against DPPH radicals and found to be effective antioxidants.

Determination of Amaryllidaceae alkaloids in snowdrop (Galanthus elwesii) from Taurus Mountains

The family Amaryllidaceae, well known for their ornamental bulbous members and its chemically important and bioactive alkaloids, has attracted the interest of phytochemists. Among these alkaloids, galanthamine has been known as an anticholinesterase inhibitor and it is used in the treatment of mild to moderate Alzheimer's disease. Moreover, antitumor, anti-inflammatory and antiprotozoal alkaloids have been isolated from different Amaryllidaceae species [1]. Among the Amaryllidaceae genera, Galanthus L. is represented in 14 taxa and one hybrid in Turkey [2]. In this study, the aerial parts and bulbs of Galanthus elwesii Hook. was collected from Akseki, Antalya. The alkaloid profile of the samples was determined by gas chromatography-mass spectroscopy (GC-MS) using Thermo GC-Trace Ultra Ver: 2.0., Thermo MS DSQ II. A TR-5 MS (30 m x 0.25 mm x 0.25 µm) column was used and GC-MS system was operated in the electron impact mode (electron energy of 70 eV). Compound identification was performed with the help of the National Institute of Standards and Technology (NIST) standard library and, where available, by comparison with the retention times and mass fragmentation patterns of standard reference compounds. Totally, twenty-four different compounds were detected. Haemanthamine, galanthindole and 6-O-methylpretazettine have been found as major constituents, whereas galanthamine was detected in very small amounts in the tested samples.

In vitro and in silico study of Piper nigrum on cyclooxygenase-2, inducible nitric oxide synthase and antioxidant enzymes

The antioxidant potential of the polyphenolic fruit extract of Piper nigrum (Piperaceae), a well known medicinal plant was evaluated. This evaluation was carried out via a reducing power assay; 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide and superoxide radical assays; and a hydrogen peroxide scavenging assay under in vitro conditions and compared with that of the standard reference compound, ascorbic acid. Moreover the phytochemical characterization of the extract was also measured by determining total phenolic, flavonoid and tannin contents and ascorbic acid content. The polyphenolic extract of P. nigrum fruits (PNE) showed significant and concentration-dependent free radical scavenging of DPPH, nitric oxide, superoxide and hydrogen peroxide radicals with inhibition percentages ranging between 71% and 158%, when compared to the standard compound ascorbic acid (140–201%). In addition to this, the extract had effective reducing power. Total phenolic content was found to be highly correlated with scavenging potential of different reactive oxygen and nitrogen species (r=0.897–0.958). In silico methods were also applied to elaborate the possibility of the interaction of bioactive compounds reported to be present in PNE with molecular antioxidant targets. The compounds showed high binding efficiencies towards catalase, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, cyclooxygenase-2 and inducible nitric oxide synthase. These results enabled us to conclude that P. nigrum fruits can be a potential source of natural antioxidants to be used therapeutically.

Synthesis of monomethyl 5,5′-dehydrodiferulic acid

Synthesis of the internal standard reference compound monomethyl 5,5′-dehydrodiferulic acid is described. The synthetic scheme relies on a selective monomethylation of the known compound 5,5′-dehydrodivanillin followed by elaboration into the dehydrodiferulic framework through a dual Horner–Emmons–Wadsworth reaction with methyl diethylphosphonoacetate. Saponification of the ester functionalities provided the target monomethyl 5,5′-dehydrodiferulic acid in 49% overall yield from 5,5′-dehydrodivanillin.