Monoterpene Hydrocarbons Research Articles

Isolation of Geranyl Acetate and Chemical Analysis of the Essential Oil from Melaleuca armillaris (Sol. ex Gaertn.) Sm.

A method was developed for the isolation of geranyl acetate from the crude essential oil (EO) of Melaleuca armillaris (Sol. ex Gaertn.) Sm. leaves, and the purity of the isolated compound was analyzed by GC/MS spectral and NMR analysis and was found to have high purity (98.9%). In addition, the EO isolated presented 0.907 g/cm3, 1.474 and [α]D20=−17.6 of density, refraction index and optical rotation, respectively. The chemical composition of the EO obtained for steam distillation from M. armillaris was analyzed by gas chromatographic and spectroscopic techniques (GC/MS and GC/FID). Thirty-eight compounds were identified, representing 99.92% of the total EO analyzed on a DB-5 ms (5% phenylmethylpolysiloxane) capillary column. This analysis showed that the EO consisted mainly of oxygenated monoterpenes (77.01%), followed by monoterpene hydrocarbons (21.31%) and sesquiterpene hydrocarbons (1.31%). Furthermore, the essential oil of M. armillaris was rich in 1,8-cineol (67 ± 2%), followed by limonene (10 ± 1%), α-Terpineol (9 ± 1%) and α-Pinene (5 ± 1%). Finally, the results suggest that the geranyl acetate isolated with high purity from crude essential oil is recommended to be explored as a component in medicinal or industrial use.

Crithmum maritimum L.-Study on the Histochemical Localization of Essential Oil.

Crithmum maritimum L. is a perennial halophyte plant that is a medicinal herb known by people from different cultures since ancient times. However, the therapeutic potential of this halophyte has not been completely investigated, and the scientific data on it are limited. The purpose of the present study was to estimate the chemical composition of the essential oil (EO) obtained from the aerial parts of Crithmum maritimum L. growing wild in Bulgaria, as well as the histolocalization of secretory structures for the synthesis and accumulation of volatile oils. The results obtained on the EO composition of Bulgarian Crithmum maritimum L. provide an opportunity to reveal potential future applications in various fields, such as medicine, pharmacy, agriculture, food, and the cosmetic industry. Gas chromatography with mass spectrometry was performed to assess the chemical profile of the isolated EO. The phenylpropanoid dillapiole was identified as the major compound in the EO, accounting for 34.09% of the total EO. Monoterpene hydrocarbons represented 62.07% of the total oil composition. γ-Terpinene, D-limonene, and β-pinene were the most abundant monoterpene hydrocarbons in the composition of the EO. In addition, histochemical localization of EO in the stem and leaves of Crithmum maritimum L. was carried out. The secretory structures were located in the cortical region of the stem and in the mesophyll tissues of the leaves in the form of secretory ducts. The performed histochemical analysis confirmed the lipophilic nature of the secretion from the duct cells. This is the first report related to the histolocalization and chemical composition of the EO from Bulgarian Crithmum maritimum L. Furthermore, our data indicate some potential possibilities for the evaluation of the therapeutic activity of the EO obtained from this plant species and outline its future applications as a therapeutic agent. Also, the EO from the studied halophyte plant has prominent potential to be used as a biopesticide, which is an environmentally friendly option compared to standard pesticides.

Chemical and biological characterization of Melaleuca subulata (Cheel) Craven leaves’ volatile constituents supported by chemometric analysis and molecular docking

BackgroundThe genus Melaleuca (Myrtaceae) comprises dozens of essential oil (EO)-rich species that are appreciated worldwide for their various medicinal values. Additionally, they are renowned in traditional medicine for their antimicrobial, antifungal, and other skin-related activities. The current study investigated the chemical profile and skin-related activities of volatile constituents derived from M. subulata (Cheel) Craven (Synonym Callistemon subulatus) leaves cultivated in Egypt for the first time.MethodsThe volatile components were extracted using hydrodistillation (HD), headspace (HS), and supercritical fluid (SF). GC/MS and Kovat’s retention indices were implemented to identify the volatile compounds, while the variations among the components were assessed using Principal Component Analysis and Hierarchical Cluster Analysis. The radical scavenging activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and β-carotene assays. Moreover, the anti-aging effect was evaluated using anti-elastase, and anti-collagenase, while the antimicrobial potential was deduced from the agar diffusion and broth microdilution assays. Lastly, the molecular docking study was executed using C-docker protocol in Discovery Studio 4.5 to rationalize the binding affinity with targeted enzymes.ResultsThe SF extraction approach offered the highest EO yield, being 0.75%. According to the GC/MS analysis, monoterpene hydrocarbons were the most abundant volatile class in the HD oil sample (54.95%), with α-pinene being the most copious component (35.17%). On the contrary, the HS and SF volatile constituents were pioneered with oxygenated monoterpenes (72.01 and 36.41%) with eucalyptol and isopulegone being the most recognized components, representing 67.75 and 23.46%, respectively. The chemometric analysis showed segregate clustering of the three extraction methods with α-pinene, eucalyptol, and isopulegone serving as the main discriminating phytomarkers. Concerning the bioactivity context, both SF and HD-EOs exhibited antioxidant effects in terms of ORAC and β-carotene bleaching. The HD-EO displayed potent anti-tyrosinase activity, whereas the SF-EO exhibited significant anti-elastase properties. Moreover, SF-EO shows selective activity against gram-positive skin pathogens, especially S. aureus. Ultimately, molecular docking revealed binding scores for the volatile constituents; analogous to those of the docked reference drugs.ConclusionsM. subulata leaves constitute bioactive volatile components that may be indorsed as bioactive hits for managing skin aging and infection, though further in vivo studies are recommended.

Decay resistance of southern pine wood containing varying amounts of resin against Fomitopsis ostreiformis (Berk.) T. Hatt.

Abstract Resin production in wood tissues is a regular feature of pine wood species, including southern pine. High resin contents of southern pine wood may increase wood resistance against decay fungi. The current study investigated the effect of resin contents in southern pine wood on decay resistance by exposing non-extracted heartwood, mixed wood (sapwood + heartwood), and sapwood blocks with varying resin content to brown rot, Fomitopsis ostreiformis in a laboratory decay test. Matching blocks of each wood type were successively extracted in a Soxhlet using three solvents to determine resin content and were exposed to decay fungus in parallel. Results showed that mass losses in non-extracted heartwood and mixed wood depended on resin content levels, and very shallow or no mass losses were observed in blocks containing more than 31 % resin content. Sapwood experienced high mass losses, but the presence of resinous extractives significantly increased the decay resistance. All solvent-extracted blocks experienced high mass loss (53–55 %). Scanning electron microscopy showed that penetration of brown rot hyphae and cell damage depended on the resin contents of blocks. Most of the identified compounds through GC-MS belonged to oleoresins, among which monoterpene hydrocarbons, oxygenated monoterpenoids, and sesquiterpenes were more abundant in heartwood than sapwood.

GC–MS analysis of essential oil from the leaves of Algerian Bupleurum plantagineum Desf.

Bupleurum plantagineum Desf. (Apiaceae) is a plant endemic to North Africa, including Algeria. It is used as natural medicine, due to its anti-inflammatory, antioxidant and hepatoprotective properties. In this work, we studied the chemical composition of the essential oil (EO) obtained by hydro-distillation from B. plantagineum leaves collected from the national park of Gouraya (Bejaïa), Algeria. Thirty components were identified in the EO by Gas chromatography–Mass Spectrometry(GC–MS) (relative abundance: 96.7%). Monoterpene hydrocarbons (56.8%) were the predominant, followed by oxygenated monoterpenes (36.7%). The main components were cis-chrysanthenyl acetate (33.5%), α-pinene (18.4%), myrcene (16.5%) and (E)-anethole (4.9%). This volatile profile differs from those reported for other Bupleurum spp. and for B. plantagineum from Algeria, suggesting the identification of a new chemotype. Overall, our results represent a contribution to the characterisation of natural products from Algeria and the preservation of its natural biodiversity. The same results will also represent a starting point for further studies on B. plantagineum.

Citrus clementine Peel Essential Oil Ameliorates Potassium Dichromate-Induced Lung Injury: Insights into the PI3K/AKT Pathway.

Acute Lung Injury (ALI) is a life-threatening syndrome that has been identified as a potential complication of COVID-19. There is a critical need to shed light on the underlying mechanistic pathways and explore novel therapeutic strategies. This study aimed to examine the potential therapeutic effects of Citrus clementine essential oil (CCEO) in treating potassium dichromate (PDC)-induced ALI. The chemical profile of CCEO was created through GC-MS analysis. An in vivo study in rats was conducted to evaluate the effect of CCEO administrated via two different delivery systems (oral/inhalation) in mitigating acute lung injury (ALI) induced by intranasal instillation of PDC. Eight volatile compounds were identified, with monoterpene hydrocarbons accounting for 97.03% of the identified constituents, including 88.84% of D-limonene. CCEO at doses of 100 and 200 mg/kg bw exhibited antioxidant and anti-inflammatory properties. These significant antioxidant properties were revealed through the reduction of malondialdehyde (MDA) and the restoration of reduced glutathione (GSH). In addition, inflammation reduction was observed by decreasing levels of cytokines tumor necrosis factor-α and tumor growth factor-β (TNF-α and TGF-β), along with an increase in phosphatidylinositide-3-kinase (PI3K) and Akt overexpression in lung tissue homogenate, in both oral and inhalation routes, compared to the PDC-induced group. These results were supported by histopathological studies and immunohistochemical assessment of TGF-β levels in lung tissues. These findings revealed that CCEO plays an integral role in relieving ALI induced by intranasal PDC and suggests it as a promising remedy.

Chemical Characterization, Leishmanicidal Activity and In Vitro Cytotoxicity of the Essential Oil Extracted from Pectis brevipedunculata (Gardner) Sch.Bip. and Its Incorporation into Microemulsion Systems.

Pectis brevipedunculata (Gardner) Sch.Bip., known in Brazil as alecrim do campo, is a small Asteraceae family plant with a calming effect and consumed as tea. This species contains components, such as neral and geranial, that display various biological activities, such as leishmanicidal. The aim was to chemically characterize the essential oil (EO) obtained from P. brevipedunculata (EO-PB) by hydrodistillation and a microemulsion formulated with EO (ME-PB), Tween 80 and Transcutol P, assess the leishmanicidal effect against Leishmania (L.) amazonensis promastigotes and cytotoxicity against RAW 264.7. EO-PB and ME-PB were analyzed by Gas Chromatography Mass Spectrometry (GC/MS). Monoterpene hydrocarbons were noteworthy among the identified compounds. The main EO-PB constituents were α-pinene and limonene, followed by neral and geranial, which were maintained in ME-PB. EO-PB presented an inhibitory concentration (IC50) of 20 µg/mL and ME-PB of 0.93 µg/mL. ME-PB inhibition towards the parasite was 20-fold higher than that of EO-PB. This indicated that EO incorporation to the microemulsion resulted in optimized biological activity. Selectivity indices indicate that ME-PB is more selective concerning parasite inhibition. Thus, ME-PB may comprise an adequate approach against Leishmania, as the inhibitory concentration (IC50) promastigotes was lower than that considered toxic for cells cell cytotoxicity of 50% (CC50).

Application of ZnO NPs, SiO2 NPs and Date Pollen Extract as Partial Substitutes to Nitrogen, Phosphorus, and Potassium Fertilizers for Sweet Basil Production.

The reduction in mineral fertilizer usage is crucial to the production of medicinal and aromatic products for safety and health purposes. Presently, nanotechnology and the utilization of natural extracts have been extensively studied due to their significant contribution. Ocimum basilicum is commonly employed for various medicinal and aromatic applications. Therefore, randomized complete block design field experiments containing 10 treatments were conducted during the 2021 and 2022 seasons to investigate the effect of nanoparticles (NPs) of ZnO (1.5 and 2.0 g/L) and SiO2 (100 and 150 mg/L) and date palm pollen extract (DPPE) at 10 and 20 g/L either alone or in combination with the ¾ or ½ NPK recommended dose (RD). The NPK RD was served as a control treatment on basil plant production in each season. The effectiveness of ZnO NPs, SiO2 NPs, and DPPE for the decrease in NPK utilization was evaluated. Meanwhile, the most effective treatment for vegetative traits (except for plant height), essential oil %, and yield was ½ NPK RD + 20 g/L DPPE + 2.0 g/L ZnO NPs. Such a treatment increased the branch number/plant, main stem diameter, relevant chlorophyll content, fresh weight/plant, dry weight/plant, essential oil %, and essential oil yield/plant by 21.00 and 9.94%, 58.70 and 40.00%, 20.69 and 15.83%, 68.83 and 58.28%, 48.70 and 56.16%, 45.71 and 35.53%, and 113.22 and 110.32% over the control in the two seasons, respectively. For total phenol and antioxidant activity, the most effective treatments were the ¾ NPK +1.5 g/L ZnO NPs and ½ NPK +2.0 g/L ZnO NPs, respectively. Simultaneously, essential oil composition (with their compound numbers identified (11-29 for control and ¾ NPK RD + 1.5 g/L ZnO NPs)) and the percentage of total compounds, monoterpene hydrocarbons, sesquiterpene hydrocarbons, and oxygenated hydrocarbons were varied among the used applications. The major observed compounds (>8%) estragole, methyl eugenol, linalool, cineole, and caryophyllene were found in different treatments. Thus, the findings of this study indicate the favorable utilization of ZnO NPs, SiO2 NPs, and DPPE in reducing the application of NPK, which may present a novel strategy and beneficial approach.

Acmella oleracea (L.) R.K. Jansen essential oils: Chemical composition, antioxidant, and cytotoxic activities

Acmella oleracea is an important food and medicinal plant in the Amazon; it is used to treat toothaches, hepatitis, malaria, fever is also described as an anticancer plant. This work reports for the first time the comparison of chemical profiles, antioxidant, and cytotoxic capacities of inflorescence (INF) and leaf (LEA) A. oleracea essential oils (EOs) obtained by hydrodistillation (HD) and steam distillation (SD). The essential oils were obtained by hydrodistillation and steam distillation and analyzed by GC and GC-MS. The antioxidant potential was evaluated by the co-oxidation method of the β-carotene/linoleic acid, and the cytotoxic activity against healthy human embryonic kidney (HEK-293), gastric ascites (AGP-01), melanoma (SK-MEL-19), lung carcinoma (A549) malignant cell lines by the MTT method. The essential oils obtained from INF by HD and SD showed the highest yields (HD = 0.68; SD = 0.5%). The monoterpene hydrocarbons (0–49.97%) and sesquiterpene hydrocarbons (25.79–50.63%) were predominant in the analyzed oils. The main constituents (>10%) identified in the EO samples were caryophyllene oxide (0.3–28.11%), E-caryophyllene (6.71–27.31%), myrcene (0–25.03%), germacrene D (0.06–19.56%), guaiol (0–14.23%), 1-pentadecene (0–13.88%), and β-pinene (0–10.04%). The chemometric analysis displayed the formation of three distinct groups of chemical compositions as follows: group I, LEA EOs (HD and SD); group II, INF EO (HD); and group III, INF EO (SD). The INF (14.3%) and LEA (9.0%) EOs showed antioxidant action with no significant difference (p < 0.05). The INF EO (HD) showed higher cytotoxicity against the malignant lineages of gastric ascites (IC50 5.31 μg/mL), melanoma (IC50 6.43 μg/mL), while the LEA EO (SD) was more cytotoxic against the lung carcinoma cell line (13.39 μg/mL), and higher toxicity was also observed against the healthy embryonic kidney cell line (IC50 5.14 μg/mL). Acmella oleracea is chemically influenced by the volatile extraction methods, and this influences on the antioxidant or cytotoxic capacity of the species.

GC-MS Analysis and Study of the Antimicrobial Activity of Citrus paradisi, Citrus aurantifolia, and Citrus sinensis Peel Essential Oils as Hand Sanitizer.

In the setting of healthcare, the use of hand sanitizers and antiseptics for hand hygiene is of paramount importance to avoid transfer of pathogenic microorganism through hand and skin contact. There is an increasing interest in the incorporation of essential oils in hand sanitizer's formula to avoid the adverse effect of conventional hand sanitizers on health. This study aimed to detect the chemical constituents of citrus peel essential oils and study their antimicrobial activity compared with commercial hand sanitizers. The qualitative and quantitative analysis of the hydrodistillated essential oils of peels of grapefruit (Citrus paradisi), lime (Citrus aurantifolia), and orange (Citrus sinensis) were carried out using gas chromatography mass spectroscopy. The disc diffusion method was used to screen the antibacterial activity of the essential oils against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Candida albicans compared with a 78% alcohol-based commercial hand sanitizer. The antimicrobial testing results were statistically analyzed. The highest yield percentage of the obtained essential oils was 1.09% obtained by orange oil. The GC-MS analysis indicated that monoterpene and sesquiterpene hydrocarbons occupied the largest portion of the chemical composition of the three essential oils with D-limonene as the most predominant component. All essential oils showed activity against all tested organisms. Lime essential oil showed comparable antimicrobial activity relative to the commercial 78% alcohol hand sanitizer. In conclusion, essential oils obtained from citrus fruit peel represent a rich source of compounds possessing antimicrobial properties and could be an alternative to synthetic antimicrobial agents.

Chemical composition and antioxidant activity of black pepper (Piper nigrum L.) fructus essential oil hydrodistillation fractions

The aim of this study was to examine the effect of hydrodistillation time on the chemical composition and antioxidant activity of collected essential oils’ (EOs’) fractions from black pepper fructus for five hydrodistillation periods: I (0-15 min), II (15-30 min), III (30-60 min), IV(60-90 min) and V (90-120 min). In this way, an essential oil with the desired chemical composition and antioxidant activity can be selected. The essential oil was obtained by Clevenger-type hydrodistillation (CHD). The qualitative and quantitative composition of the collected EOs’ fractions was determined by GC-MS and GC-FID analysis. The efficiency of EOs’ fractions to scavenge DPPH radicals was evaluated spectrophotometrically. Essential oil yield was 3.0 ± 0.050 ml/100 g of plant material after 120 min of CHD. The content of monoterpene hydrocarbons and aromatic compounds decreased, while the content of oxygenated monoterpenes, sesquiterpene hydrocarbons and oxygenated sesquiterpenes increased with the time of CHD. The most abundant compound of EOs’ fractions was (E)-caryophyllene, whose content increased with the time of CHD (I-V: 24.9-36.6%). Results indicated that all collected EOs’ fractions exhibited antioxidant activity (EC50 values were in the range I-V: 81.27±0.327–8.02±0.044 mg/ml), where fraction V showed the highest activity. This study proved that CHD time and fractionation affect the composition and antioxidant activity of black pepper essential oil. Future research may be extended to examine other biological activities of black pepper EOs’ fractions, as well as synergistic effects of other identified active components of the essential oil, in addition to (E)-caryophyllene, that would affect biological activities.

Volatile metabolites, antioxidant and biological activities of Bursera simaruba (L.) Sarg. essential oil, from the tropical dry forest, Cesar, Colombian Caribbean Region

Tropical Dry Forest (T-dF) is one of the most threatened ecosystems in the Neotropics, due to negative anthropogenic impacts on biodiversity and ecosystem services. Bursera simaruba (L.) Sarg. (indio desnudo, resbalamono), is among the species most reported for the T-dF of the Colombian Caribbean. In this work, the chemical composition and antioxidant and biological activities of B. simaruba essential oil (EO) were determined. EO chemical analysis from leaves and, petiole, and young branches bark (PYBB) of B. simaruba was carried out by Gas Chromatography coupled to Mass Spectrometry; polar and apolar columns were used for component separation. The biological activity of B. simaruba EO (PYBB) against Lasioderma serricorne (Coleoptera, Ptinidae) was determined by the preference area method. EO (PYBB) antioxidant capacity was determined by Oxygen Free Radical Absorbance Capacity (ORAC) assay. Reference antioxidant and standard terpenes were used for relative analysis of ORAC results. α-Terpinene (27.7% and 16.4%), p-cymene (22.8% and 44.0%), and g-terpinene (16.7% and 14.6%), were the main constituents in B. simaruba EOs (leaves and PYBB). EOs were represented by a high percentage of hydrocarbon monoterpenes (∼79.1% and ∼88.9%, leaves and PYBB); while hydrocarbon sesquiterpenes (∼3.1% and ∼4.6%, leaves and PYBB); contributed with a low percentage. B. simaruba EO (PYBB), showed attractant activity, at 0.4 μL.cm-2 (2h: -45%±7%; 4h: -50%±17%); in relation with Stay off, at 0.8 μL.cm-2, which was used as a positive control for repellent activity (2h: 66%±5%; 4h: 75%±21%). B. simaruba EO (PYBB) showed a very low antioxidant capacity (ORAC: 657.2±20.5 μmol Trolox/g sample), related to quercetin, used as reference antioxidant (50816.9±1559.1 μmol Trolox/g sample). However, EO ORAC was higher than the α-terpinene (68.0±10.8 μmol Trolox/g sample), γ-terpinene (51.2±2.0 μmol Trolox/g sample), p-cymene (105.6±6.4 μmol Trolox/g sample), used as standard terpenes. In conclusion, this is the first report on the chemical composition of the B. simaruba EO from Colombia, whose results differ from the previous ones from Jamaica and Guadeloupe. Chemical composition, reported here, with α-terpinene, γ-terpinene and p-cymene as principal compounds, could be used to establish a scientific support that explains some traditional uses. EO showed an attractive biological activity on L. serricorne. EO showed an antioxidant activity lowest quercetin (antioxidant reference), but higher that standard terpenes (α-terpinene, γ-terpinene and p-cymene).

CHEMICAL COMPOSITION OF EXTRACTS AND ESSENTIAL OILS OBTAINED FROM COMMON JUNIPER (JUNIPERUS COMMUNIS L.) IN AZERBAIJAN

Juniperus communis L. (common juniper) is a widespread plant species in the Western region of Azerbaijan. The dependence of the composition and content of various biologically active substances in juniper on natural climatic conditions was studied. The results of the study of the substances obtained from the extraction of leaves and branches in ethanol were presented. The composition of volatile compounds was studied by the gas chromatography technique. In all samples, monoterpene hydrocarbons always predominated with percentages higher than 70% (from 71.12% for the plant material collected in August to 74.38% for those in September), followed in similar quantities by oxygenated monoterpenes or sesquiterpene hydrocarbons with values between 10.45% and 12.77% and between 10.50% and 12.72%, respectively. Ascorbic acid content varying from 33.1 to 123.2 mg/100 g was also determined. The investigation of the yield of essential oils in different months of the year showed that its amount varies depending on the season (3.5-4.4% of the mass of dry raw materials).

Chemical profile, enzyme inhibitory and antioxidant activities of essential oils of an endemic Algerian species: Abies numidica. De Lannoy ex Carrière

ABSTRACT The essential oils (EOs) from needles, twigs and cones of Abies numidica, an endemic tree from Algeria, were analysed by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and 13C nuclear magnetic resonance (13C NMR). Fifty, forty-nine, and thirty-eight components from needles, twigs and cones were identified accounting for 86.0%, 93.5% and 93.8% of the total EO, respectively. EOs were mainly composed of monoterpene hydrocarbons (46.3%-86.0%), followed by sesquiterpene hydrocarbons (2.6%-33.6-%). The antioxidant activity was determined using five tests: ABTS, β-Carotene bleaching, DPPH, FRAP and phosphomolybdenum. Cholinesterase inhibition potential of EOs was also evaluated. EO of cones was found to have the highest antioxidant activity for most of the tests performed. All EOs exhibited better antiacetylcholinesterase (AChE) than antibutyrylcholinesterase (BChE) activities at various rates. The most potent AChE inhibition was observed for twigs EO (IC50 = 2.73 g/mL), followed by needles (IC50 = 4.09 µg/mL) while cones’ EO showed least potential (IC50 = 13.64 µg/mL).

Essential oil from Senecio rudbeckiifolius Meyen &amp; Walp.: Chemical analysis, antioxidant assessment, and literature review of Senecio essential oils

Species of the genus Senecio have the largest medicinal value for the Andes communities, and studies on the biological activities attributed to them are scarce. Among them, Senecio rudbeckiifolius Meyen &amp; Walp. is used in decoction for rheumatic affection and skin allergies. The chemical composition and antioxidant activity of the leaf essential oil from plants grown in the Peruvian Andes were studied. Eighty compounds were identified in the essential oil. Monoterpene hydrocarbons had the major percentage (91.4%), followed by oxygenated monoterpenes (4.2%). The most abundant compounds were myrcene (23.4%), b-phellandrene (17.1%), sabinene (15.1%) and limonene (11.7%). In addition, the possible applicability of volatile metabolites for revealing taxonomic/evolutionary relationships among Senecio species was explored. Antioxidant activity were examined using 1,1-diphenyl-2-picryl-hydrazyl and ferric reducing antioxidant power assays. The essential oil had a moderate scavenging effect and it showed ferric reducing activity.

Composition and Anti-Acetylcholinesterase Properties of the Essential Oil of the Ecuadorian Endemic Species Eugenia valvata McVaugh.

Alzheimer's disease is a global health problem due to the scarcity of acetylcholinesterase inhibitors, the basis for symptomatic treatment of this disease; this requires new approaches to drug discovery. In this study, we investigated the chemical composition and anticholinesterase activity of Eugenia valvata McVaugt (Myrtaceae) collected in southern Ecuador, which was obtained as an essential oil (EO) with a yield of 0.124 ± 0.03% (w/w); as a result of the chemical composition analysis, a total of 58 organic compounds were identified-representing 95.91% of the total volatile compounds-using a stationary phase based on 5% phenyl-methylpolysiloxane, as analyzed via gas chromatography coupled to mass spectrometry (GC-MS) and flame ionization detection (GC-FID). The main groups were hydrocarbon sesquiterpenes (37.43%), oxygenated sesquiterpenes (31.08%), hydrocarbon monoterpenes (24.14%), oxygenated monoterpenes (0.20%), and other compounds (3.058%). Samples were characterized by the following compounds: α-pinene (22.70%), α-humulene (17.20%), (E)-caryophyllene (6.02%), citronellyl pentanoate (5.76%), 7-epi-α-eudesmol (4.34%) and 5-iso-cedranol (3.64%); this research was complemented with an enantioselective analysis carried out using 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin as a stationary phase chiral selector. As a result, α-pinene, limonene, and α-cadinene enantiomers were identified; finally, in the search for new active principles, the EO reported strong anticholinesterase activity with an IC50 of 53.08 ± 1.13 µg/mL, making it a promising candidate for future studies of Alzheimer's disease.

Greek Fir Seeds and Cones as Underestimated Source of Essential Oil: Composition and Biological Properties

Greek fir (Abies cephalonica) seeds and cone scales were used, for the first time, for an analysis of their biologically active volatile compounds. It was observed that the yield of seed essential oil was 18%, which, among plants, is impressive. The seed essential oil was characterized by a distinctive forest scent with a subtle lemon undertone. The determination of the chemical compositions of the hydrodistilled oils isolated from the seeds and cone scales, achieved via chromatographic and spectroscopic methods (MS, NMR), revealed more than 100 compounds, mostly monoterpene hydrocarbons. The above methods allowed for the identification of 99.4% and 98.3% of the total seed and cone scale oil compositions, respectively. Limonene in its enantiomeric levorotatory form (S) constituted over 80% of the essential oil isolated from the Abies cephalonica seeds. This abundance of limonene makes them a potential natural source for obtaining this compound, which has demonstrated various biological properties. The main cone essential oil compounds were α- and β-pinenes as well as limonene. The cytotoxic effects of both essential oils were analyzed using the MTT assay in skin fibroblasts, keratinocytes, and melanoma cell lines, in the range of 0.012–0.2 μL/mL of essential oil. The cone scale essential oil was slightly more cytotoxic and induced a decrease in the cell viability in concentrations of 0.05–0.1 μL/mL, with small differences between the cell lines. The tested essential oils did not have selective effects on the melanoma cells (A375 and C32) when compared with normal cells. Both the seed and cone scale essential oils revealed good antimicrobial effects on Staphylococcus aureus and Escherichia coli.

Phytochemical study on the essential oils of Callitris glaucophylla Joy Thomps. & L.A.S. Johnson, and assessment of their antioxidant, anti-enzymatic and allelopathic effects

Callitris glaucophylla Joy Thomps. & L.A.S. Johnson is a coniferous forest species of the Cupressaceae family native to Australia. This species is rich in essential oils (EOs) but few studies about variability and biological activity of these EOs are available in the literature. The purpose of this study was to evaluate the variability of production of C. glaucophylla EOs in relation to the different plant parts (needles, cones and stems) and to investigate their antioxidant, anti-enzymatic and herbicidal properties. EOs were obtained by hydro distillation and analyzed by GC and GC-MS. The antioxidant potential of EOs was assessed by ABTS, FRAP and DPPH assays, their phytotoxic activities were evaluated against germination and shoots and radical growth of Sinapis arvensis, Trifolium campestre, Lepidium sativum and Lolium rigidum. The EOs were evaluated for their possible anti-enzymatic effects with spectrophotometric assay. EOs resulted rich in monoterpenes hydrocarbons (61.04–77.82 %) and oxygenated monoterpenes (19.52–25.26 %). The main compounds were α-pinene as major compound in all plant parts (36.99–59.84 %), 1,8-cineole (19.88 % in stems) and limonene (18.94 % in needles). Herbicidal assays showed that all EOs have remarkable and significant phytotoxicity towards germination, roots, and aerial parts growth of the tested plants, depending on the EO, the doses and tested species. The EOs showed significant free radical scavenging potential and resulted more active against cholinesterases than α-glucosidase and α-amylase. The data obtained constitute an important contribution in selecting and valorizing appropriate forestry tree biomass as sources of antioxidant and phytotoxic molecules for sustainable application in food preservation and weeds control. The activities against the tested enzymes confirmed a possible use of these EOs as natural pesticides.

Chemical composition and content of essential oil from cultivated bald cypress (Taxodium distichum L.)

The essential oils extracted from the cone scale (CS), seed (SE), and thin branch with leaf (BL) of Taxodium distichum harvested during the winter season were analyzed by gas chromatography-mass spectrometry. Up to 37 components were identified, accounting for more than 96% of the total oil volume in all samples. Monoterpenes (CS 93.4%, SE 85.2%, and BL 72.8%) represented the major constituents of the essential oils, followed by smaller quantities of sesquiterpenoids. Monoterpene hydrocarbons (MH) dominated, with limonene (CS 56.5%, SE 50.5%, and BL 43.8%) and α-pinene (CS 31.7%, SE 26.1%, and BL 16.2%) being the main constituents. Representative minor constituents in the CS oil are camphene (1.3%) and bornyl acetate (2.6%); in the SE oil, β-myrcene (1.7%) and bornyl acetate (5.1%) were found; and in BL essential oil, β-myrcene (3.1%) and bornyl acetate (6%). Sesquiterpene hydrocarbons (CS 4.6%, SE 7.8%, and BL 12.9%) were the other major subclasses of components, with caryophyllene (CS 4.1%, SE 6.8%, and BL 9.3%) as the main constituent. The only oxygen-containing sesquiterpene found was caryophyllene oxide (CS 1.5%, SE 5.5%, and BL 8.3%). The compounds could be of great interest in food, cosmetics, and pharmaceutical applications.

In Vitro Screening of Antimicrobial and Anti-Coagulant Activities, ADME Profiling, and Molecular Docking Study of Citrus limon L. and Citrus paradisi L. Cold-Pressed Volatile Oils.

Citrus, which belongs to the Rutaceae family, is a very widespread genus in the Mediterranean Basin. In Tunisia, various parts of these spontaneous or cultivated plants are used in common dishes or in traditional medicine. The purpose of this work was to investigate C. limon and C. paradisi essential oil (EO). The samples were studied for their chemical composition using SPME/MS, as well as their antibacterial and antifungal activities. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) methods were used to evaluate the anticoagulant potentialities. The obtained results show that both essential oils are rich in monoterpenes hydrocarbons, whereby limonene is the main compound in C. paradisi EO (86.8%) and C. limon EO (60.6%). Moreover, C. paradisi EO contains β-pinene (13.3%), sabinene (2.2%) and α-pinene (2.1%). The antibacterial assay of the essential oils showed important bactericidal and fungicidal effects against all strains tested. In fact, the MICs values of C. limon EO ranged from 0.625 to 2.5 mg/mL against all Gram-positive and Gram-negative bacteria, and from 6.25 to 12.5 mg/mL for Candida spp. strains, while C. paradisi EO was more active against all bacteria with low MICs values ranging from 0.192 to 0.786 mg/mL, and about 1.5 mg/mL against Candida species. Both tested Citrus EOs exhibited interesting anticoagulant activities as compared to heparin. The molecular docking approach was used to study the binding affinity and molecular interactions of all identified compounds with active sites of cytidine deaminase from Klebsiella pneumoniae (PDB: 6K63) and the C (30) carotenoid dehydrosqualene synthase from Staphylococcus aureus (PDB: 2ZCQ). The obtained results show that limonene had the highest binding score of -4.6 kcal.mol-1 with 6K63 enzyme, and -6.7 kcal.mol-1 with 2ZCQ receptor. The ADME profiling of the major constituents confirmed their important pharmacokinetic and drug-like properties. Hence, the obtained results highlight the potential use of both C. limon and C. paradisi essential oils as sources of bioactive compounds with antibacterial, antifungal, and anti-coagulant activities.