Chemical composition and bioactivities of essential oils from Pulicaria vulgaris subsp. dentata (Sm.) Batt. growing in Tunisia

Investigating the antiproliferative and antioxidant potential of xanthoxylin and of essential oil isolated from Pulicaria incisa (Lam.) DC. herbal medicine

In this study have been evaluated the antiproliferative and antioxidant activities of Israeli Pulicaria incisa (Lam.) DC. essential oil (Pi1), of essential oil partially purified by xanthoxylin (Pi2), one of its feature metabolites, and the isolated xanthoxylin (Xan). From the compositional analysis carried out by GC-MS oxygenated monoterpenes class was the main class (71.18 %), with cis-chrysanthenol (55.66 %) as the most abundant components, following by carvotanacetone (11.68 %). Other metabolites represented the second class (20.33 %), being xanthoxylin (15.35 %) the principal metabolites, isolated and characterized by NMR tecniques. Pi1 and Xan showed good antioxidant activity causing a clear reduction in ROS levels and an increase in CAT and SOD activity, while Pi2 showed a reduction in enzymatic activity. Furthermore, Pi1 and Xan demonstrated an apoptotic antiproliferative effect in a dose-dependent manner on solid and hematological tumors, unlike Pi2 which showed lower activity. These data showed that P. incisa EO had interesting antioxidant and antitumor activity and that the biological activities exhibited by the essential oil as a whole are mainly due to xanthoxylin.

Chemical profile, antiproliferative and pro-apoptotic activities of essential oils of Pulicaria arabica against A549 lung cancer cell line

Pulicaria arabica has been traditionally utilized in folk medicine for various purposes such as ulcer treatments as well as antidiarrheal agent. Herein, the chemical profiles of Pulicaria arabica essential oils (PAEOs) and the in vitro antiproliferative effect of PAEOs were investigated. Hydrodistillation was employed to prepare PAEOs which were then characterized by GC/MS, while the antiproliferative effects were investigated by MTT assay as well as flow cytometric and RT-PCR analysis. Sixty-four (99.99 %) constituents were recognized from PAEOs. Carvotanacetone (36.97 %), (-)-carvomenthone (27.20 %) and benzene, 2-(1,1-dimethylethyl)-1,4-dimethoxy- (6.92 %) were the main components. PAEOs displayed IC50 values ranging from 30 to 50 μg/mL. DNA content analysis revealed that A549 cells exposed to PAEOs exhibited an increase in G1 cells population. The flow cytometry analysis results also showed that the PAEOs antiproliferative effect was mediated via apoptosis induction. Furthermore, a modulation in the pro-apoptotic markers (caspase-3 and Bax) and anti-apoptotic (Bcl-2) was also observed. In conclusion, PAEOs exhibited a moderate anti-proliferative effect on A549 cells through modulating the cell cycle progression and apoptosis initiation. These findings could offer a potential therapeutic use of PAEOs in lung cancer treatment.

The chemical composition of the aerial parts essential oil of Pulicaria odora (L.) Rchb. growing in Sicily (Italy)

The genus Pulicaria Gaertn. (Asteraceae) comprises more than ninety-two species as annual or perennial herbs or small shrubs, distributed in Africa, Europe, and Asia, and concentrated mainly in the Mediterranean region. Several species have been used in the traditional medicine of many countries. In the present study the chemical composition of the essential oil from aerial parts of Pulicaria odora (L.) Rchb., present in the Mediterranean region and collected in Sicily, was analysed by GC-MS. No papers have been previously published on the essential oil of the aerial part of this species. The result showed the presence of large quantity of carbonyl compounds (25.29%), oxygenated sesquiterpenes (23.28%) and thymol derivatives (16.76%). Chemical considerations with respect of other oils of Pulicaria taxa were carried out.

Essential Oil Composition, Antioxidant Activity and Leaf Micromorphology of Five Tunisian Eucalyptus Species

Eucalyptus species have been widely employed in the projects of reforestation in Tunisia. Although their ecological functions are controversial, these plants are indeed important to counteract soil erosion, and represent a fast-growing source of fuelwood and charcoal wood. In the present study, we considered five Eucalyptus species, namely Eucalyptus alba, E. eugenioides, E. fasciculosa, E. robusta, and E. stoatei cultivated in the Tunisian Arboreta. The aim was to carry out the micromorphological and anatomical characterization of the leaves, the extraction and phytochemical profile of the essential oils (EOs), and the evaluation of their biological properties. Four of the EOs showed the prevalence of eucalyptol (1,8-cineole) varying from 64.4 to 95.9%, whereas a-pinene predominated in E. alba EO (54.1%). These EOs showed in vitro antioxidant activity, and reduced the oxidative cellular stress as shown by their activity on reactive oxygen species (ROS) production, and modulation of the expression of antioxidant enzymes, such as glutamate-cysteine ligase (GCL) and heme oxygenase-1 (Hmox-1). Moreover, the EOs inhibited the production of nitric oxide (NO), showing anti-inflammatory activity. The data collected suggest that these EOs may be considered a promising therapeutic strategy for inflammation-based diseases and may represent an additional value for the economy of Tunisia.

Chemical Composition, Toxicity and Repellency of Inula graveolens Essential Oils from Roots and Aerial Parts against Stored-Product Beetle Tribolium castaneum (Herbst)

In this work, essential oils extracted from roots and aerial parts of Inula graveolens by hydrodistillation and their fractions obtained by chromatographic simplification were first investigated for their chemical composition by GC/MS and then evaluated for the first time for their repellency and contact toxicity properties against Tribolium castaneumadults. Twenty-eight compounds were identified in roots essential oil (REO), which accounted for 97.9 % of the total oil composition, with modhephen-8-β-ol (24.7 %), cis-arteannuic alcohol (14.8 %), neryl isovalerate (10.6 %) and thymol isobutyrate (8.5 %) as major constituents. Twenty-two compounds were found in the essential oil from aerial parts (APEO), which accounted for 93.9 % of the total oil, with borneol (28.8 %), caryophylla-4(14),8(15)-dien-6-ol (11.5 %), caryophyllene oxide (10.9 %), τ-cadinol (10.5 %) and bornyl acetate (9.4 %) as main compounds.REO and APEO displayed stronger repellency after 2 h of exposure (80.0 and 90.0 %, respectively) against T. castaneum at the concentration of 0.12 μL/cm² . After fractionation, fractions R₄ and R₅ exhibited greater effects (83.3 % and 93.3 %, respectively) than the roots essential oil. Furthermore, the fractions AP₂ and AP₃ showed higher repellency (93.3 and 96.6 %, respectively) than the aerial parts oil. The LD₅₀ values of oils from roots and aerial parts topically applied were 7.44 % and 4.88 %, respectively. Results from contact toxicity assay showed that fraction R₄ was more effective than the roots oil with LD₅₀ value of 6.65 %. These results suggests that essential oils of roots and aerial parts from I. graveolens may be explored as potential natural repellent and contact insecticides against T. castaneum in stored products.

A Comparative Study of the Chemical Composition by SPME-GC/MS and Antiradical Activity of Less Common Citrus Species

Citrus secondary metabolites, such as terpene compounds, are very important for human health due to their bioactivity including anti-inflammatory, anti-cancer, and antioxidant effects. In this work, for the first time, the volatile chemical composition of peels and juices from four different Citrus species (C. junos, Citrus × aurantium, C. aurantium 'Bizzarria' and C. medica 'Florentina', commonly known as Yuzu jeune, Oni Yuzu, Bizzarria orange and Florence cedar, respectively) was investigated by Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique and the antiradical activity was also examined. The results showed that limonene and γ-terpinene were the main volatile substances detected both in the juices and in the peels, followed by other minority compounds responsible for the phyto-complex of the unique aromas which characterize each individual analyzed Citrus species. Principal component analysis (PCA), performed on volatile compounds, showed both some correlation as well as a clear separation between the juice and the peel of each species. Among them, Oni Yuzu juice was found to be the richest in total polyphenols and flavonoids while its capacity to scavenge ABTS^•+ and DPPH^• radicals was similar to that of Yuzu Jeune and Bizzarria orange.

Anti-tyrosinase and Anti-butyrylcholinesterase Quinolines-Based Coumarin Derivatives: Synthesis and Insights from Molecular Docking Studies

In this work, a series of anti-tyrosinase and anti-butyrylcholinesterase coumarin derivatives 4a–f and 5a–f were synthesized starting from 4-hydroxycoumarin. The condensation of 2-(arylimin)-4-hydroxycoumarins 3a–f with dimethylformamide dimethyl acetal (DMF-DMA), used as a key reaction, afforded the precursors 4a–f, whose acid treatment led to the formation of 5a–f. These prepared heterocycles were characterized by spectroscopic means including ¹H-NMR, ¹³C-NMR, and DCI-HRMS. Their anti-tyrosinase and anti-butyrylcholinesterase activities have been evaluated in vitro and some of them exhibited promising activity supported by the molecular docking analysis to estimate possible interactions between these compounds and active sites of both proteins tyrosinase (PDB: 2Y9W) and butyrylcholinesterase (PDB: 4TPK).

Inter-Individual versus Inter-Population Variability of Calendula suffruticosa subsp. algarbiensis Hexane Extracts

Calendula suffruticosa subsp. algarbiensis (Boiss.) Nyman is very common on the Portuguese coast, but it has only recently begun to be studied chemically and belongs to a genus of difficult taxonomic classification. To improve the knowledge on the chemical variability of this taxon and evaluate the possible use of this tool for taxonomical purposes, the aim of this work was to determine the extent of chemical variation between individuals collected in the same geographic region, and to compare with samples mixing fragments of several individuals each (populations) from different local environments. Overall, hexane extract analysis by GC/MS allowed to identify 42 compounds, eight fatty acids, 24 terpenoids, three alcohols, five alkanes, and two pollutants. Greater chemical differences were found between individuals, grown in the same region, than were found between population samples from different regions. Additionally, 25 phytochemicals were identified for this taxon for the first time and may be used for taxonomic classification, even to distinguish between subspecies of C. suffruticosa. Furthermore, plants collected near urban areas accumulated pollutants, indicating the importance of controlling local environmental conditions when C. suffruticosa cultivation is for human consumption.

Chemical Composition and New Biological Activities of Essential Oil and Hydrosol of Hypericum perforatum L. ssp. veronense (Schrank) H. Lindb

The chemical profile, antiproliferative, antioxidant and antiphytoviral activities of the species Hypericum perforatum ssp. veronense (Schrank) H. Lindb. (Clusiaceae) were investigated. Free volatiles were isolated and the chemical composition was determined in the lipophilic fraction (essential oil) and for the first time in the water fraction (hydrosol). The aim is to provide phytochemical data for H. perforatum ssp. veronense useful for distinguishing ssp. veronense from ssp. angustifolium, as there are taxonomic disagreements between them and the composition of the secretory products may be helpful in this respect. In the essential oil, the most abundant compounds identified were α-pinene and n-nonane, while in the hydrosol, myrtenol, carvacrol and α-pinene were the most abundant. Overall, the class of monoterpenes and oxygenated monoterpenes dominated in the EO and hydrosol samples. The essential oil showed high antioxidant activity, in contrast to the antiproliferative activity, where the hydrosol showed exceptional activity against three cancer cell lines: Hela (cervical cancer cell line), HCT116 (human colon cancer cell line) and U2OS (human osteosarcoma cell line). Both the essential oil and hydrosol showed antiphytoviral activity against tobacco mosaic virus infection on the local host plants. This is the first report dealing with biological activities of hydrosol of H. perforatum ssp. veronense, and the obtained results suggest that this traditional medicinal plant is a valuable source of volatiles with promising antiproliferative, antioxidant and antiphytoviral activities.

Sesquiterpenes-Rich Essential Oil from Above Ground Parts of Pulicaria somalensis Exhibited Antioxidant Activity and Allelopathic Effect on Weeds

Pulicaria genus (fleabane) is characterized by its fragrant odor due to the presence of essential oil (EO). According to the literature reviews, the EO of Pulicaria somalensis O.Hoffm. (Shie) is still unexplored. For the first time, 71 compounds were characterized in EO derived from above-ground parts of P. somalensis collected from Saudi Arabia. Sesquiterpenes represented the main components (91.8%), along with minor amounts of mono-, diterpenes, and hydrocarbons. Juniper camphor (24.7%), α-sinensal (7.7%), 6-epi-shyobunol (6.6%), α-zingiberene (5.8%), α-bisabolol (5.3%), and T-muurolol (4.7%) were characterized as main constituents. The correlation analysis between different Pulicaria species showed that P. somalensis has a specific chemical pattern of the EO, thereby no correlation was observed with other reported Pulicaria species. The EO showed significant allelopathic activity against the weeds of Dactyloctenium aegyptium (L.) Willd. (crowfoot grass) and Bidens pilosa L. (hairy beggarticks). The IC50 value on the germination of D. aegyptium was double that of B. pilosa. The IC50 values on the root growth of B. pilosa and D. aegyptium were 0.6 mg mL−1 each, while the shoot growths were 1.0 and 0.7 mg mL−1, respectively. This variation in the activity could be attributed to the genetic characteristics of the weeds. Moreover, the EO exhibited significant antioxidant effects compared to ascorbic acid. Further studies are necessary to verify if these biological activities of the EO could be attributable to its major compounds.