Abdelaziz Abbad

Chemical composition and antioxidant and anticandidal activities of essential oils from different wild moroccan thymus species

Samples of the aerial parts of Thymus broussonetii, T. ciliatus, T. leptobotrys, T. maroccanus, T. pallidus, T. satureioides, and T. serpyllum collected from different natural regions in southern and south‐western Morocco were analyzed for their qualitative and quantitative essential oil profiles. In total, 46 compounds, representing more than 99% of the oils, were characterized. Monoterpenes, both hydrocarbons (12.9–58.0%) and oxygenated monoterpenes (38.8–81.1%), were the principal classes of compounds for most of the thyme species studied. Cluster analysis allowed the classification of the species into three main groups: a carvacrol group (Group I), comprising the species T. maroccanus and T. leptobotrys, a linalyl acetate and (E)‐nerolidol group (Group II), represented by T. serpyllum, and a thymol and/or carvacrol, γ‐terpinene, and p‐cymene group (Group III), composed of T. satureioides, T. broussonetii, T. ciliatus, and T. pallidus. The essential oils were screened for their antioxidant and anticandidal activities. The data showed that the oils obtained from T. leptobotrys and T. maroccanus (carvacrol group) possessed the highest antioxidant activities as assessed by the determination of the DPPH free radical‐scavenging ability and the ferric‐reducing potential. The anticandidal assays indicated that the highest activity was noticed for the essential oil isolated from T. leptobotrys.

Essential oil composition and antimicrobial activity of wild and cultivated mint timija (Mentha suaveolens subsp. timija (Briq.) Harley), an endemic and threatened medicinal species in Morocco

The hydro-distilled essential oils obtained from aerial parts of the wild (w) and cultivated (c) mint timija (Mentha suaveolens subsp. timija), an endemic medicinal species of Morocco, have been analyzed by GC–MS and screened for antimicrobial activity. In total, 35 compounds representing more than 98% of the oils were identified. Menthone (39.4(w)–10.8(c)%), pulegone (62.3(c)–34.3(w)%) and isomenthone (9.3(c)–7.8(w)%) were found as the main components for the two oils. The volatiles of the wild and cultivated material differed significantly in both the percentage of the main components and antimicrobial effect. Pulegone was more dominant in cultivated mint timija (62.3%) than in wild one (34.3%), while menthone was more abundant in the wild material (39.4%). In the antimicrobial assays, both oils displayed good to excellent activity against all microorganisms tested with the oil of the cultivated form being more active.

Essential Oil Composition and Antimicrobial Activity of Wild and Cultivated Moroccan Achillea ageratum L.: a Rare and Threatened Medicinal Species

The essential oils of leaves and flowers of the wild and cultivated Moroccan Achillea ageratum L., a rare and threatened medicinal species, were examined by GC/MS, and their chemical compositions were compared. At least nine components were identified in both wild and cultivated A. ageratum oils, representing more than 95% of the oils. Artemisyl acetate (62.34–78.79%), yomogi alcohol (4.89–12.40%), santolina alcohol (4.86–11.77%), and artemisia alcohol (3.36–7.04%) were the major compounds. Terpene‐alcohol proportion was higher in wild A. ageratum than in cultivated A. ageratum. The antibacterial analysis showed that both oils presented high activity against all the studied Gram‐positive strains in a range of MIC values from 2.55 to 7.02 mg/ml, but they appeared not effective against the tested Gram‐negative ones (MIC values 20.40–41.10 mg/ml). They also exhibited remarkable antifungal activities against Candida species with MIC values ranging from 5.83 to 8.42 mg/ml. From these results, it was concluded that domestication of this threatened medicinal species using clonal propagation did not significantly affect its chemical composition and consequently its antimicrobial properties.

Chemical characterization and insecticidal properties of essential oils from different wild populations of Mentha suaveolens subsp. timija (BRIQ.) HARLEY from Morocco

The present study is the first investigation of the volatile‐oil variability and insecticidal properties of the endemic Moroccan mint Mentha suaveolens subsp. timija (mint timija). The yield of essential oils (EOs) obtained from different wild mint timija populations ranged from 0.20±0.02 to 1.17±0.25% (v/w). GC/MS Analysis revealed the presence of 44 oil constituents, comprising 97.3–99.9% of the total oil compositions. The main constituents were found to be menthone (1.2–62.6%), pulegone (0.8–26.6%), cis‐piperitone epoxide (2.9–25.5%), piperitone (0.3–35.5%), trans‐piperitone epoxide (8.1–15.7%), piperitenone (0.2–9.6%), piperitenone oxide (0.5–28.6%), (E)‐caryophyllene (1.5–11.0%), germacrene D (1.0–15.7%), isomenthone (0.3–7.7%), and borneol (0.2–7.3%). Hierarchical‐cluster analysis allowed the classification of the EOs of the different mint timija populations into four main groups according to the contents of their major components. This variability within the species showed to be linked to the altitude variation of the mint timija growing sites. The results of the insecticidal tests showed that all samples exhibited interesting activity against adults of Tribolium castaneum, but with different degrees. The highest toxicity was observed for the EOs belonging to Group IV, which were rich in menthone and pulegone, with LC50 and LC90 values of 19.0–23.4 and 54.9–58.0 μl/l air in the fumigation assay and LC50 and LC90 values of 0.17–0.18 and 0.40–0.52 μl/cm2 in the contact assay.

Intraspecific chemical variability of essential oil from leaves of Cupressus atlantica Gaussen, an endemic and endangered coniferous species in Morocco

The composition of essential oils isolated from leaves of 11 natural populations of Cupressus atlantica, an endemic and endangered coniferous species from Morocco, was investigated by GC-MS. In total, 42 essential oil components were identified, accounting for 73.1–97.7% of the total oil. Monoterpene (25.2–84.9%) and sesquiterpene hydrocarbons (12.2–46.8%) were the principal subclasses of compounds, with α-pinene (15–65.4%), germacrene D (5.9–30.5%), δ-3-carene (2–16.6%) and γ-cadinene (1.3–9.8%) as the main constituents. The results of the oil composition were analysed by hierarchical cluster and principal component analysis that established three main groups of essential oils. These oils were differentiated by the content of the major constituents (α-pinene, germacrene D, δ-3-carene and γ-cadinene), geographical location and climatic characteristics.

Essential Oil Composition of Juniperus Phoenicea from Morocco and Tunisia

Abstract The essential oil of dried leaves of Moroccan and Tunisian Juniperus phoenicea (Cupressaceae) was isolated by direct hydrodistillation (Clevenger-type apparatus) and analyzed using GC (FID) and GC-MS. Forty five compounds in Moroccan oil (72 % of the oil) and thirty one compounds in Tunisian oil (99 % of the oil) were identified. The most abundant compounds in J. phoenicea oils were Opinene (35.46, 38.20 %) and ð-3-carene (7.6, 11.69 %) respectively. Essential oil of Tunisian juniper is characterized by a high percentage of ô-3-carene and limonene with respectively 11.69 %, 10.29 % in comparison to 7.6 % and 1.1 % for the Moroccan juniper. The sesquiterpenes fraction is more abundant in Tunisian juniper with a significant percent of ß-selinene (7.32 %), followed by ß-caryophyllene (4.76 %) and Ot-cubebene (4.15 %).

Cytotoxic withanolides from the leaves of Moroccan Withania frutescens

Abstract Context: Withania species are a rich source of interesting phytochemical substances (withanolides) which have shown several biological properties. Objective: To investigate the cytotoxic potential of Withania frutescens (L.) Pauquy (Solanaceae) leaf extracts and isolated active compounds against cultured tumor cell lines. Materials and methods: The crude methanol extract of W. frutescens leaves was partitioned with dichloromethane, ethyl acetate and n-butanol. MeOH extract and its fractions were tested for their cytotoxic activity against cancer cell lines (HepG2 and HT29) using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Bioassay-guided fractionation was performed for the active CH2Cl2 fraction employing column chromatography and preparative high-performance liquid chromatography. Structural elucidation of the isolated active compounds was carried out mainly by 1D and 2D NMR and mass spectrometry. The compounds were then tested for their cytotoxic activity. Results: The CH2Cl2 fraction was the most active against HT29 cell line. The fractionation procedure resulted in the isolation of 4β,17α,27-trihydroxy-1-oxo-22-R-witha-2,5,24-trienolide (1), 5β,6β-epoxy-4β,17α,27-trihydroxy-1-oxowitha-2,24-dienolide (2) and 2,3-dihydroxywithaferin A-3β-O-sulfate (3). The latter exhibited the strongest cytotoxic activity against HT29 cancer cell lines (IC50 of 1.78 ± 0.09 µM) which was comparable to that of 5-fluorouracil (5-FU) used as the positive antimitotic control. Discussion and conclusion: Compounds 2 and 3 were isolated from W. frutescens for the first time. Data obtained suggest that the sulfated steroidal lactone (3) can be considered as a compound with potential application in the new anticancer drugs development field.

Insecticidal properties and chemical composition of essential oils of some aromatic herbs from Morocco

The essential oils (EOs) of Artemisia herba alba, Rutachalepensis and Satureja calamintha aerial parts were analysed by GC/MS and the EOs were tested for their toxicity against two flour beetles, Tribolium castaneum and Tribolium confusum. EO composition showed that the major compounds were pulegone, menthone and menthol for S. calamintha, camphor and β-thujone for A. herba alba and 2-undecanone for R. chalepensis. Contact bioassay showed that all EOs were toxic to adults of T. castaneum and T. confusum. Higher toxicity was found with the EOs from S. calamintha and R. chalepensis (LD50 of 0.09–0.13 μL/cm2 and LD90 of 0.17–0.29 μL/cm2). In fumigant toxicity test, A. herba alba and S. calamintha EOs produced insecticidal activity with S. calamintha EO being more toxic with LD50 and LD90 values of 10.5 and 19.1 μL/L air, respectively, for T. confusum against 7.8 and 17.4 μL/L air, respectively, for T. castaneum.

Acaricidal properties of essential oils from Moroccan plants against immature ticks of Hyalomma aegyptium (Linnaeus, 1758); an external parasite of the spur-thighed tortoise (Testudo graeca)

ABSTRACT Hyalomma aegyptium (Linnaeus, 1758) is a hard-tick species of the Ixodidae family with the main adult hosts being Palearctic tortoises of the genus Testudo. In Morocco, it is commonly found infecting Testudo graeca that has a wide geographic distribution and is subject to protection through international illegal trade legislation. This tortoise tick has been reported as an important vector of various human and animal pathogens. Unfortunately, to date, there are no strategies to control this hematophagous ectoparasite. The present study was conducted in laboratory to evaluate the acaricidal activity of essential oils (EOs) extracted from six plants of Moroccan origin as an alternative against H. aegyptium. All EOs tested displayed toxic effects on different life stages of H. aegyptium. Mentha suaveolens subsp. timija (LC50 = 0.910 µL/mL and LC90 = 1.465 µL/mL) and Satureja calamintha EOs (LC50 = 0.927 µL/mL and LC90 = 1.347 µL/mL) exhibited higher activity against hatching eggs, whereas Chenopodium ambrosioides EO was comparatively more toxic to larvae (LC50 = 0.444 µL/mL and LC90 = 0.918 µL/mL). Juniperus thurifera var. africana (LC50 = 0.0045 mL/cm2 and LC90 = 0.0118 mL/cm2) and Lavandula pedunculata subsp. atlantica EOs (LC50 = 0.0036 mL/cm2 and LC90 = 0.0110 mL/cm2) caused high mortality in nymphs. The effect of different EOs is discussed according to their chemical composition and bioactive components.

Synergistic effects of three Moroccan thyme essential oils with antibiotic cefixime

The association of essential oils (EOs) with antibiotics provides a promising solution towards combating resistant bacteria. Thus, the aim of this study was to examine for the first time the possible synergistic interaction between EOs of three Moroccan thymes, namely Thymus leptobotrys (carvacrol [79.1%]), Thymus pallidus (γ-terpinene [29.6%], thymol [26.8%] and p-cymene [18.9%]) and Thymus ciliatus (carvacrol [26.2%], p-cymene [19.6%], thymol [17.3%] and γ-terpinene [14.6%]) and the antibiotic cefixime against selected pathogenic bacteria. The results showed that all thyme EOs presented interesting antibacterial potency and important synergistic effects with cefixime. Thymus leptobotrys EO showed the strongest efficacy against all tested bacteria (minimum inhibitory concentration values 0.14 mg/mL to 73.92 mg/mL), and the best synergistic effect (fractional inhibitor concentration indices: 0.26 to 0.5; gain: 4- to 130-fold). This synergistic interaction between the studied thyme EOs and cefixime may provide a basis for future applications for the control of antibiotic-resistant bacteria.RésuméLa combinaison des huiles essentielles (HEs) avec les antibiotiques constitue une solution prometteuse pour surmonter les problèmes de l’émergence de la résistance des bactéries aux antibiotiques. Ainsi, ce travail a pour objectif principal d’évaluer pour la première fois la synergie entre les HEs de trois espèces de thyms marocaines, à savoir Thymus leptobotrys (carvacrol [79,1 %]), Thymus pallidus (γ-terpinène [29,6 %], thymol [26,8 %], p-cymène [18,9 %]) et Thymus ciliatus (carvacrol [26,2 %], p-cymène [19,6 %], thymol [17,3 %], γ-terpinène [14,6 %]) et l’antibiotique céfixime sur quelques bactéries pathogènes. Les résultats obtenus ont montré que toutes les HEs de thyms étudiées ont présenté un pouvoir antibactérien très intéressant, ainsi qu’un effet synergique important en combinaison avec l’antibiotique céfixime. L’HE extraite de Thymus leptobotrys a montré l’activité inhibitrice la plus forte sur toutes les souches testées (CMI: 0,14 à 73,92 mg/ml). Cette HE combinée avec la céfixime a montré aussi l’effet synergique le plus important (indices de concentration inhibitrice fractionnaire (FICIs): 0,26 et 0,5; gain: 4 à 130 fois). Ces interactions synergiques entre les HEs de thyms étudiées et la céfixime peuvent présenter une plateforme pour le développement de nouvelles applications dans le contrôle de la résistance des bactéries aux antibiotiques.