Identification and Biological Activity of Volatile Organic Compounds Isolated from Plants and Insects. III. Chromatography-Mass Spectrometry of Volatile Compounds of Aegopodium podagraria

Gas chromatography-mass spectrometry identified more than 20 volatile organic compounds isolated from leaves and flowers ofAegopodium podagrariaL.     

Determination of trace elements in drinking tea by various analytical techniques

Tea has been one of the most popular simulating beverages which is both heavily produced and consumed in Taiwan. The determination of minor or trace elements in drinking tea and tea leaves is therefore important for estimating the daily intake of Taiwanese considered as a safety indicator. In order to accurately and precisely determine the concentrations of trace elements in samples, several analytical methods such as AAS, NAA and ICP-AES are suggested. This paper attempts to utilize all three methods to determine the concentrations of minor or trace elements in different types of tea leaves and the extracts percolated from them. The influence of fermentation processes on the concentration levels of minor or trace elements in tea samples is investigated. Because only free metal ions are bioavailable for the human body, it is necessary to determine their concentrations in drinking tea. The dissolution of trace elements in drinking tea is therefore studied by simulating the common Chinese style of tea percolation. Concentrations of thirteen elements including Zn, Mn, Ca, Cu, Ni, Al, K, Mg, Cd, Pb, Na, Co and Sc are determined.     

Green analytical methodologies for the discovery of bioactive compounds from marine sources

The application of green analytical chemistry in search of bioactive compounds is of paramount importance, leading to the development of environmentally friendly methodologies for their isolation. This work provides an up-to-date overview of the analytical methodologies based on a green perspective for the discovery of bioactive compounds from marine sources, namely to their extraction and structural characterization. Both the characteristics of marine bioactive compounds and the sustainable evaluation of their bioactivity are also addressed.     

The contribution of various analytical techniques to the certification of reference materials

Two international intercomparisons on the determination of trace elements in geological-environmental materials as well as two similar intercomparisons with biological materials provided a large amount of data elucidating the relative significance of various analytical techniques in the process of certification. The data have been investigated concerning their frequency of use, agreement of results by various techniques, percentage of outliers and general performance of the methods. Because many laboratories supplied results for both biological materials and both materials of mineral origin, the analysis of data in the form of two-sample charts has also been presented. The significance of an adequate procedure for outlier rejection for the proper assigning of certified values is emphasized and the unique role of neutron activation analysis in the certification process has been demonstrated. The use of highly reliable (definitive) methods for the verification of recommended values has been demonstrated.     

Determination of natural uranium by various analytical techniques in soils of Zacatecas State (Mexico)

Journal of Radioanalytical and Nuclear Chemistry - 238U is a radionuclide present in the earth’s crust that provides 65.9% of annual average radiation dose and represents 99.27% of total...     

Novel lignans from the stems and leaves of Trachelospermum jasminoides

Two novel 5-methoxydibenzylhydroxybutyrolactone lignans named 5-methoxytracheloside and 5-methoxytrachelogenin were isolated from the stems and leaves of Trachelospermum jasminoides(Lindl.) Lem.,their structures were determined as(8S,8’S)-8’- hydroxy-3,3’,4,5-tetramethoxylignan-9,9’-olide-4’-O-β-D-glucopyranoside and(8S,8’S)-4’,8’-dihydroxy-3,3’.4,5-tertramethoxylignan -9,9’-olide by various spectroscopic analysis.5-Methoxytracheloside was a new compound and 5-methoxytrachelogenin was isolated from natural source for the first time.     

Bioactive furanocoumarins from the stems and leaves of Clausena hainanensis

A new furanocoumarin, clauhainanin A (1), together with seven known furanocoumarins (2–8), were isolated from the stems and leaves of Clausena hainanensis. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. All known compounds (2–8) were isolated from C. hainanensis for the first time. All isolated compounds were evaluated for their cytotoxicities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1–8 exhibited significant inhibitory effects with IC₅₀ values ranging from 1.36 to 18.96 μM.     

Identification and antibacterial evaluation of bioactive compounds from Garcinia kola (Heckel) seeds

We assessed the bioactivity of G. kola seeds on Streptococcus pyogenes, Staphylococcus aureus, Plesiomonas shigelloides and Salmonella typhimurium. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by the agar-well diffusion method and their activities were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture, while GC-MS was used to identify the phytocomponents of the fractions. The inhibition zone diameters of the extracts ranged from 0-24 ± 1.1 mm, while MIC and MBC values ranged between 0.04-1.25 mg/mL and 0.081-2.5 mg/mL, respectively. The chloroform/ethyl acetate/formic acid (CEF) solvent system separated more active compounds. The MIC of the fractions ranged between 0.0006-2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels of linoleic acid, 1,2-benzenedicarboxylic acid and 2,3-dihydro-3,5-dihydroxy-6-methyl ester, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.     

Petroleum heteroatom compounds in various commercial delayed coking liquids: characterized by FT-ICR MS and GC techniques

Delayed coking is an important petroleum resid conversion process. The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids. Eight commercial delayed coking liquids were characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatographic techniques. High relatively abundant heteroatom compounds in the coking liquids were 1–4 aromatic-ring pyridinic nitrogen compounds, carbazoles, benzocarbazoles, phenols, mercaptans, benzothiophenes, dibenzothiophenes, and naphthobenzothiophenes. Coking liquids derived from various feeds had similar compound class types, molecular weight distribution ranges, and double bond equivalents (DBE). However, the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied. A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process. The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.     

Comparison of various analytical techniques for homogeneity test of candidate standard reference materials

Three different analytical techniques: INAA, X-ray fluorescence and atomic absorption spectrometry were used at the JRC Ispra to test the total homogeneity of four candidate botanic reference materials supplied by NBS. Without adopting complex statistical formalities a “degree of inhomogeneity” was estimated in each sample for the elements considered in the test. The operating procedures and the results obtained are presented and discussed.     

New phenolic glycosides from the stems and leaves of Casearia multinervosa

Four phenolic glycosides (1-4), including two new ones (3 and 4), have been isolated from the stems of Casearia multinervosa and identified as arbutin (1), 4-O-E-caffeoylarbutin (2), 4-O-E-coumaroylarbutin (3) and 4-O-E-feruloylarbutin (4), respectively. In addition, the two known phenolic glycosides (1 and 2) were also isolated from the leaves. Structures were elucidated on the basis of spectroscopic evidence. Compounds 1-4 were tested for cytotoxicity against the P388 mouse lympholytic cell line by an ATP Lite-M assay method and showed mild to moderate activity.     

New challenges in environmental analytical chemistry: Identification of toxic compounds in complex mixtures

Toxic effects evidenced in the environment are most often caused by mixtures of known and unknown pollutants. One of the key challenges in environmental chemistry and ecotoxicology is to characterize and identify those toxicants in relation with the effect. However, many of the current bottlenecks in the assessment of organic contaminants in our environment are related to the difficulty of evaluating various chemical classes and biological effects within complex mixtures and more precisely to link both approaches. To tackle these analytical challenges, the bioanalytical concept has emerged during the last decade. In this article, we describe through some outstanding examples the current limitations in the chemical-driven approach such as problems encountered for a correct evaluation of water quality when the continuous introduction of new chemicals has to be taken into account in monitoring for correct evaluation of this quality and could led to tremendous analytical costs or some of the integrated bioanalytical approaches as promising powerful tools to improve environmental risk assessment by taking into account the link presence/effect.     

Dhasingreoside: new flavonoid from the stems and leaves of Gaultheria fragrantissima

A new flavonoid, dhasingreoside (1) and seven known compounds, quercetin 3-O-β-d-galacturonopyranoside (2), quercetin 3-O-β-d-galactopyranoside (3), quercetin 3-O-β-d-glucuronopyranoside (4), quercetin 3-O-α-l-rhamnopyranoside (5), (–)-epicatechin (6), salicylic acid (7) and gaultherin (8), have been isolated from the shade-dried stems and leaves of Gaultheria fragrantissima, commonly known as ‘Dhasingre’ in Nepal. The structures were elucidated on the basis of physical, chemical and spectroscopic methods. Among known compounds, five compounds (3–6 and 8) were isolated for the first time from G. fragrantissima. In vitro antioxidant activity of all the isolated compounds was evaluated by 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging assay. Dhasingreoside (1) and other compounds (2–6) showed significant free radical-scavenging activity.     

Determination of PASHs by various analytical techniques based on gas chromatography-mass spectrometry: application to a biodesulfurization process

Polycyclic aromatic sulphur heterocyclic (PASH) compounds, such as dibenzothiophene (DBT) and alkylated derivatives are used as model compounds in biodesulfurization processes. The development of these processes is focused on the reduction of the concentration of sulphur in gasoline and gas–oil [D.J. Monticello, Curr. Opin. Biotechnol. 11 (2000) 540], in order to meet European Union and United States directives.

The evaluation of biodesulfurization processes requires the development of adequate analytical techniques, allowing the identification of any transformation products generated. The identification of intermediates and final products permits the evaluation of the degradation process.

In this work, seven sulfurated compounds and one non-sulfurated compound have been selected to develop an extraction method and to compare the sensitivity and identification capabilities of three different gas chromatography ionization modes. The selected compounds are: dibenzothiophene (DBT), 4-methyl-dibenzothiophene (4-m-DBT), 4,6-dimethyl-dibenzothiophene (4,6-dm-DBT) and 4,6 diethyl-dibenzothiophene (4,6 de-DBT), all of which can be used as model compounds in biodesulfurization processes; as well as dibenzothiophene sulfoxide (DBTO₂), dibenzothiophene sulfone (DBTO) and 2-(2-hydroxybiphenyl)-benzenesulfinate (HBPS), which are intermediate products in biodesulfurization processes of DBT [ A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa, Biochem. Eng. J. 26 (2005) 168]. Furthermore, a non-sulfurated compound, 2-hydroxybiphenyl (2-HBP), has also been selected as it is the final product in the biodesulfurization process of DBT [A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa. Biochem. Eng. J. 26 (2005) 168].

Since, typically, biodesulfurization reactions take place in a biphasic medium, two extraction methods have been developed: a liquid–liquid extraction method for the watery phase and a solid phase extraction method for the organic phase. Recoveries of the selected compound in both media were studied. They were in the range of 80–100% for the watery and in the range of 40–60% for the organic phase, respectively.

Gas chromatography coupled to mass spectrometry (GC–MS) has been employed for the identification of these selected compounds. Three different ionization modes were applied: conventional electron impact (EI); positive chemical ionization (PCI), using methane as the reagent gas; and a recently developed ionization mode known as hybrid chemical ionization (HCI), using perfluorotri-n-butylamine as the reagent gas. Limits of detection and identification capabilities have been compared between the three analytical techniques.

The sensitivity of the three analytical techniques was studied and LOD between 0.05 and 1, between 0.09 and 2 and between 0.001 and 0.043 were achieved for PCI, EI and HCI, respectively.

The developed method was applied in samples from a biodesulfurization process. The biodesulfurization reactions were conducted in resting cell operation mode, using Erlenmeyer flasks or an agitated tank bioreactor. The microorganism employed was Pseudomonas putida CECT 5279. The reaction was performed under controlled air flow, stirring and temperature conditions.     

A new cycloartane triterpenoid from the leaves and stems of Fritillaria hupehensis

A new triterpenoid has been isolated from the leaves and stems of Fritillaria hupehensis Hsiao et K.C.Hsia.Its structure wasestablished as(23Z)-9,19-cycloart-23-ene-3α,25-diol 1 through chemical and spectroscopic studies including 2D NMR.Anotherknown triterpenoid 9,19-cycloart-25-ene-3β,24ξ-diol 2 was also isolated.     

A new triterpenoid glycoside from the leaves and stems of Duranta repens

A new triterpenoid glycoside (1) was isolated from the methanol extract of the leaves and stems of Duranta repens L. (Verbenaceae) along with 14 known compounds consisting of eight triterpenoids, four iridoids, one phenylethanoid glycoside and one flavonoid. The chemical structure of 1 was determined to be bayogenin 3-O-[β-D-glucopyranoside]-28-O-[α-L-rhamnopyranosyl-(1→5)-O-β-D-apiofuranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranosyl] ester, based on spectroscopic data. In addition, the inhibitory effects of the isolates on lipoxygenase activity were examined. Among them, acteoside and apigenin resulted in 94 ± 3.6% and 82 ± 4.7% inhibition, respectively, at 0.5 mM.     

A novel prenylated xanthone from the stems and leaves of Calophyllum inophyllum

A novel prenylated xanthone, caloxanthone Q, was isolated from the stems and leaves of Calophyllum inophyllum. The structure elucidation was carried out by detailed spectroscopic analysis.