ИДЕНТИФИКАЦИЯ НЕИЗВЕСТНОГО КОМПОНЕНТА ЭКСТРАКТА ВОЛОС ЭКСГУМИРОВАННЫХ ЧЕЛОВЕЧЕСКИХ ОСТАНКОВ ПО МАСС-СПЕКТРОМЕТРИЧЕСКИМ И ГАЗОХРОМАТОГРАФИЧЕСКИМ ДАННЫМ

The real example of GC-MS identification of unknown constituent of human hair extract belonging to the exhumed remains is considered. The identification of this constituent (molecular weight 238 Da) was unsuccessful using both its standard mass spectrum (electron ionization) in combination with lib­ra­ry search, and its GC retention index value (~1540 on semi-standard non-polar polydimethyl siloxane stationary phases with 5% phenyl groups). However, its identification appea­red to be possible using the original algorithm of data processing. This approach implies revealing the structural analogues of unknown analytes, primarily their homologues which differ by molecular masses on ± 14 Da and by composition on CH2 homolo­go­us difference. This approach allowed revealing such analogues of unknown analyte as Flavesone (2,2,4,4-tetramethyl-2-isobutyrylcyclohexa-1,3,5-trione), Leptospermone (2,2,4,4-tetramethyl-2-isopentanoylcyclohexa-1,3,5-trione), and some others. All these compounds belong to a rather “exotic” class of natural compounds knows as cyclic b-triketones. Based on the obtained data, the possible structure of the constitu­ent under the consideration was proposed as 2,2,4,4-tetramethyl-2-propionylcyclohexa-1,3,5-trione. The principal fea­ture of cyclic b-triketones is their existence in a few tautomeric forms. Another tautomer of triketone under discussion is 5-hydroxy-2,2,6,6-tetramethyl-4-propionyl-4-en-1,3-dio­ne (CAS № 87552-01-0). This compound is found to be the constituent of Leptosper­mum scoparium essential oil and some other plants, and it belongs to the group of structural analogues of Flave­sone. The most known pharmaceutical application of essential oils containing these compounds are the components of conditioners for hair and skin. The results confirm this formerly un­known component does not belong to the group of toxic substances. This excludes the criminal origin of the remains.

Th e chemical composition of the essential oil obtained from the fruits of Pimpinella affi nis Ledeb. (Apiaceae) was analyzed by gas chromatography (GC) and gas chromatography - mass spectrometry (GC-MS) techniques. Twenty - four components were identifi ed in the essential oil of P. affi nis Ledeb., whose major constituents were geijerene (17.68%), limonene (12.86%), pregeijerene (9.92%), germacrene D (8.54%) and trans- β-ocimene (4.94%). Th e essential oil was evaluated for antibacterial and antifungal activities. Th e oil showed antimicrobial activity against all the tested microorganisms, excepted Pseudomonas aeruginosa. Maximum activity was observed against fungal microorganisms. Key words: Antimicrobial; apiaceae, essential oil, Pimpinella affi nis Ledeb

Non-traditional VOC emissions, including emerging pollutants, air toxics, and volatile chemical products (VPCs) span a range of volatilities and molecular structures that impact their reactivity in the atmosphere and eventual fate. However, little is known their source apportionment, temporal behavior, and relative importance to health impacts along with ozone and SOA formation. With the need to characterize these emissions, comprehensive measurement techniques that capture the unexpected but are also highly specific to detail molecular structure and provide compound quantification are needed.The work presented in this study uses chemical ionization (CI) techniques (H3O+, NH4+, NO+, O2+) for the direct detection and quantification of VOCs considered to be hazardous air pollutants (HAPs). With our work, we show that the ionization patterns for these classes of compounds within each ionization scheme can be used to expand these methods to interpret unknown signals in complex environments. This detailed characterization was conducted by coupling in-situ gas chromatography (GC) to the CI-TOF-MS for pre-separation of the complex mixture. Our results show how the speciated data can be used to deconvolve the complexities of chemical ionization detection (including the presence of fragmentation, cluster formation, and mixed ionization schemes e.g. proton transfer, charge transfer, dehydration).To apply these methods to ambient atmospheric measurements we need to reconcile the need for both continuous isomer specific quantification and high time resolution data. To accomplish this, we simultaneously coupled the in-situ GC with both CI and electron ionization (EI) TOF-MS. Resulting in the generation of three data sets (GC-EI, GC-CI, and direct-CI data) that offer continuous GC quantification, universal detection of speciated organics (EI), speciated CI data to constrain interferences, and direct-CI data for high time resolution data. This instrument combination was deployed in Spring 2023 for a 4-week mobile laboratory campaign in a region of southeast Louisiana, US that is dense with petrochemical production and industrial activity, to quantify hazardous air pollutants to gauge exposure for the local population. The combination of the in-situ GC, EI-TOF-MS, PTR-TOF-MS was used to provide highly specific, quantitative data on VOCs considered to be air toxics in the area, while also acquiring high time resolution PTR-TOF data that allowed the characterization of different point sources and their variability over time-of-day and day-of-week.

In this work, gas chromatography tandem with electron ionization and full-scan high-resolution mass spectrometry with a time-of-flight mass analyzer was evaluated for analyzing pesticide residues in teas. The relevant aspects for mass spectrometry analysis, including the resolution and mass accuracy, acquisition rate, temperature of ion source, were investigated. Under acquisition condition in 2-GHz extended dynamic range mode, accurate mass spectral library including 184 gas chromatography detectable pesticides was established and retrieval parameters were optimized. The mass spectra were consistent over a wide concentration range (three orders) with good match values to those of NIST (EI-quadrupole). The methodology was verified by the validation of 184 pesticides in four tea matrices. A wide linear range (1-1000 μg/kg) was obtained for most compounds in four matrices. Limit of detection, limit of quantification, and limit of identification values acquired in this study could satisfy the requirements for maximum residue levels prescribed by the European Community. Recovery studies were performed at three concentrations (10, 50, and 100 μg/kg). Most of the analytes were recovered at an acceptable range of 70-120% with relative standard deviations ≤ 20% in four matrices. The potential extension of qualitative screening scope makes gas chromatography tandem with electron ionization and mass spectrometry with a time-of-flight mass analyzer a more powerful tool compared with gas chromatography with tandem mass spectrometry.

Chemical composition analysis and antioxidant activity evaluation of essential oil from Orthosiphon thymiflorus (Roth) Sleesen

Yen Bai province has 50,000 hectares under cinnamon cultivation, which is the largest of cultivation area in Vietnam. Cinnamon essential oil is mainly extracted from the stem bark and leaves of Cinnamomum cassia (L.) J. Presl. The essential oil yield varies depending on species and extraction methods. The aim of this study was to investigate the effect of critical parameters including extraction time, average particle size and material mass to water volume ratio on the yield of essential oil and to evaluate its chemical constituents. The stem bark of Cinnamomum cassia was sourced from Yen Bai province, Vietnam. The powdered stem bark (500 g) was extracted with 2.5 L of distilled water by hydro-distillation for 180 minutes. The chemical composition of the essential oil obtained was determined by Gas Chromatography – Mass Spectrometry (GC-MS) analysis. Morphological changes to the cinnamon bark powder before and after hydro-distillation was assessed by Scanning Electron Microscopy (SEM) and Fourier Transform Infra-Red (FTIR) Spectroscopy. Essential oil (14.95 mL) was obtained corresponding to a percentage yield of 3.38%. The GC-MS analysis identified 11 bioactive compounds in thecinnamon essential oil. Cinnamaldehyde was the major compound in cinnamon essential oil constituting about 93.3% of the total oil composition. Generally, cinnamon from Yen Bai province in Vietnam provides a high value essential oil with a high percentage of cinnamaldehyde, and a potential for many applications.

In this study, the chemical composition of essential oils isolated from dried stems, leaves, and fruits of three wild sages from Northern Iran (Artemisia absinthium L., Artemisia annuaL., and Artemisia tschernieviana B) were investigated by a combination of gas chromatography (GC) and gas chromatography (GC)/mass spectrometry (MS). A total of 83 components were identified accounting for 93.51 to 100.00% of the oil composition. A. absinthium oils were characterized by high amounts of β-thujone (24.27 to 40.91%), 1,8-cineole (8.10 to 14.09%), and sabinene(8.35 to 10.05%). A. annua yielded an oils rich in camphor (10.54 to 24.12%), borneol (1.48 to 27.78%), and 1,8-cineole (8.03 to 11.71%). β -pinene (13.65 to 22.37%), limonene (7.69 to 13.65%), and cubenol (3.50 to 15.43%) were the main components in the essential oils of A. tschernieviana. The total numbers of volatile compounds identified from A. absinthium, A. annua, and A. tschernieviana were 58, 84, and 86, respectively. In A. absinthium and A. annua, monoterpens were higher than the sesquiterpens, and oxygenated monoterpene compounds were the main constituents, but in oils of A. tschernieviana, monoterpene hydrocarbons were the main constituents. The results of the antimicrobial activity of all essential oils showed that the oils had varying degrees of growth inhibition against the microorganisms tested. Key words: Artemisia absinthium, Artemisia annua, Artemisia tschernieviana,Compositae, essential oil composition, antimicrobial activity.

No domínio Cerrado podemos encontrar inúmeras espécies vegetais que podem produzir óleos essenciais como metabólitos de segunda ordem, como o Cochlospermum regium, conhecido popularmente por algodão-do-cerrado. Objetivou-se caracterizar a constituição química e avaliar a atividade antioxidante do óleo essencial extraído das flores de C. regium. As flores de C. regium foram coletadas em uma área de Cerrado, em Rio Verde/GO, Brasil. A espécie foi identificada pelo primeiro autor e uma exsicata depositada no herbário do (IF Goiano). Para extração do óleo essencial foram utilizadas 100g de flores e submetido à hidrodestilação em aparelho tipo Clevenger. Foi determinado o rendimento do óleo essencial. Em seguida o óleo essencial foi analisado por cromatógrafo gasoso associado à espectrometria de massas (CG-EM) e avaliado o seu potencial antioxidante pela técnica de sequestro de radicais livres DPPH. O rendimento médio de óleo essencial foi igual a 0,099%. Durante a análise de CG-EM foram identificados 32 compostos, destacando-se o caryophylleno E (9,76%), γ-muuroleno (16,69%) e bicyclogermacreno (39,82%). A atividade antioxidante apresentou para as concentrações entre 50 a 2 mg mL-1 100% de redução do radical DPPH, e reduções entre as concentrações 1 a 0,031 mg mL-1 de 85,77 a 13,18% (EC50). Conclui-se que o óleo essencial de C. regium apresentou baixo rendimento de extração, entretanto apresenta rico em compostos sesquiterpenos hidrocarbonados e oxigenados, e como excepcional agente antioxidante e antifúngico natural no combate a Sclerotinia sclerotiorum. Sendo assim, o óleo essencial das flores de C. regium apresenta um forte candidato para novas pesquisas que poderão ser aplicadas nas áreas da saúde, agrícola e alimentícia.

There are around 140 species in the genus Callicarpa, with 23 species occurring in Vietnam. The Vietnamese Callicarpa species have been poorly studied. In this work, the leaf essential oils of C. bodinieri, C. candicans, C. formosana, C. longifolia, C. nudiflora, C. petelotii, C. rubella, and C. sinuata, have been obtained from plants growing in central Vietnam. The chemical compositions of the essential oils were determined using gas chromatography – mass spectrometry. Mosquito larvicidal activities of the essential oils were carried out against Aedes aegypti. All of the Callicarpa leaf essential oils showed larvicidal activity, but two samples of C. candicans were particularly active with 48-h LC50 values of 2.1 and 3.8 μg/mL. Callicarpa candicans essential oil should be considered as a potential alternative mosquito control agent.

Culiseta longiareolata (Macquart, 1838) (Diptera, Culicidae) is one of the important mosquito species distributed in Algeria. It acts as a vector of avian malaria, tularemia, Malta fever (brucellosis), and several arboviruses, such as West Nile fever and western encephalitis virus. To eliminate undesirable insect vectors of pathogens, botanical-based insecticides are increasingly recommended. This research was focused on the analysis of the chemical composition of essential oils from Artemisia absinthium (Asteraceae) and Thymus serpyllum (Lamiaceae) obtained by hydrodistillation using gas chromatography – mass spectroscopy (GC-MS). Furthermore, these oils were tested for the first time for their larvicidal activity against fourth-instar larvae of C. longiareolata. In the Th. serpyllum essential oil, linalool (25.40%) was the major constituent, followed by camphor (19.75%) and α-pinene (11.25%). In the A. absinthium essential oil, the major compound was camphor (39.01%), followed by chamazulene (14.51%). Our study found significant larvicidal effects against the fourth-instar larvae, with a direct correlation among the larval mortality rate, applied concentrations, and duration of exposure to the treatment, where the mortality increased over time. Also, the results indicated a significant difference in the mortality rate between the two samples of essential oils. The essential oil extracted from A. absinthium was highly effective against mosquito larvae, achieving the LC50 values of 10.42, 6.19 and 3.82 ppm at 24, 48, and 72 h, respectively, while the essential oil from Th. serpyllum achieved the LC50 values of 12.16, 7.79, and 6.88 ppm. Based on the current results, both the plants could be used as new alternatives for mosquito control.

Essential oils (EO) from leaves and branches of Nectandra puberda Schott (Nees) and from leaves of N. cuspidata Nees & Mart. were obtained by hydrodistillation and their chemical compositions determined by gas chromatography - mass spectrometry (GC-MS). The main compounds identified from N. puberula EO were apiole (22.2%), β-caryophyllene (15.1%), β-pinene (13.3%), germacrene D (8.3%), pogostol (6.6%) and bicyclogermacrene (6.4%) in the leaves; and apiole (28.1%), pogostol (19.8%) and guaiol (11.2%) in the branches. The EQ of N. cuspidata leaves showed β-caryophyllene (26.9%), bicyclogermacrene (16.0%) and spathulenol (5.2%) as the main compounds. The EOs were subjected to antibacterial screening and displayed promising activity against Escherichia coli (MIC = 19.5 μg.mL⁻¹). In addition, the EOs were tested for cytotoxic activity against MCF-7 breast tumor cells and the IC₅₀ values were 64.5 ± 1.6 and 117.1 ± 11.9 μg.mL⁻¹ for the leaf EOs of N. puberula and N. cuspidata, respectively.

Eucalyptus citriodora is a well‐known source of essential oil. Essential oil from the fruit's of E. citriodora was extracted using the hydrodistillation method with the help of a Clevenger‐type apparatus (yield 0.23%). The phytochemicals composition of the oil was evaluated using gas chromatography (GC), GC/ mass spectrometry (MS) and nuclear magnetic resonance (NMR) techniques. The essential oil was found to be a complex mixture of mono‐ and sesquiterpenoids. The major chemical constituents identified were α‐pinene (54.1 g/100 g), γ‐terpinene (8.6 g/100 g), E‐caryophyllene (6.6 g/100 g), β‐pinene (6.3 g/100 g), limonene (5.5 g/100 g) and 1,8‐cineole (4.3 g/100 g). In vitro cytotoxicity of the essential oil was evaluated using the sulphorhodamine B (SRB) assay against human lung carcinoma (A549), human epithelial cervix carcinoma (HeLa) and Chinese hamster ovarian carcinoma (CHOK1) cells. The IC50 values of the E. citriodora fruits essential oil against A549, HeLa and CHOK1 cells ranged from 87.5 to 96.8 µg/ml. The toxicity of the isolated essential oil was also assessed against human lymphocytes using the [3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] (MTT) assay. Essential oil possesses significant cytotoxic activity. The aim of the present study was to search the Northwestern Himalaya for the new potent source of toxicologically safe essential oils. This is a first report on the chemical composition and cytotoxicity of essential oil extracted from the fruit's of E. citriodora. Copyright © 2015 John Wiley & Sons, Ltd.

The species Morella pubescens, commonly known as wax laurel, is a tree belonging to the Myricaceae family that can be found from Costa Rica to Bolivia. In this study, the chemical composition, enantiomeric distribution, and biological activity of essential oil isolated from the leaves of this species was determined. Hydrodistillation was used to isolate the essential oil (EO). Gas chromatography coupled with mass spectrometry was used to determine the qualitative composition, gas chromatography equipped with a flame ionization detector was used to determine quantitative composition, and gas chromatography on an enantioselective column was used to determine enantiomeric distribution. The broth microdilution method was employed to assess the antibacterial capacity of the essential oil against seven opportunistic microorganisms, including three Gram-positive cocci bacteria, a Gram-positive bacilli bacterium and three Gram-negative bacilli bacteria. 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical cation and 2,2-diphenyl-1-picrylhydryl free radical were used as reagents to determine the antioxidant activity of essential oil. The spectrophotometric method was used to analyze the acetylcholinesterase inhibitory effect of the essential oil. The extraction method afforded a low yield of around 0.076 ± 0.008% (v/w). Fifty-eight chemical compounds, which represent 97.9% of the total composition, were identified in the essential oil. Sesquiterpene hydrocarbons were the most representative group with 24 compounds (67.8%). The principal constituents were (E)-caryophyllene (27.5 ± 1.3%), limonene (11.8 ± 0.6%), δ-selinene (9.1 ± 0.2%), β-selinene (8.0 ± 0.2%), selina-3,7(11)-diene (5.3 ± 0.2%) and germacrene B (5.0 ± 0.5%). Three pairs of enantiomers were identified in the essential oil of Morella pubescens. Essential oil presented strong activity against the bacterium Enterococcus faecium (ATCC 27270) with an MIC of 250 μg/mL. The antioxidant activity of essential oil was very strong in the ABTS method with an SC50 of 46.4 ± 1.0 µg/mL and was strong in the DPPH method with an SC50 of 237.1 ± 1.8 µg/mL. Additionally, the essential oil reported strong anticholinesterase activity with an IC50 of 133.5 ± 1.06 µg/mL.

Ocimum gratissimum L. is a fragrant plant of the Lamiaceae family. O. gratissimum has been used in folk medicine, cosmetics, and food industry. In this study, herbs of O. gratissimum were collected in the summer in Northern Vietnam and extracted for essential oils by hydrodistillation, followed by gas chromatography - mass spectrometry (GC-MS) analysis. The efficiency of essential oil extraction was 0.2258% ± 0.0735. According to the analysis results, twenty-seven components were identified. The main ingredients include Eugenol (65.135%), Ocimene <(Z) -b-> (7.20%), Caryophyllene <E-> (6.64%), and Germacrene D (12.03%). This result suggests that the O. gratissimum essential oil is a potential source of antimicrobial, preservative and flavoring agent.

Identification of metabolites from liquid chromatography–coulometric array detection profiling: Gas chromatography–mass spectrometry and refractionation provide essential information orthogonal to LC–MS/microNMR