Rachid Chemli

Chemical composition of 8 eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities

BackgroundIn 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi.MethodsThe essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out.ResultsTwenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils.ConclusionsE. odorata showed the strongest activity against S. aureus, H. influenzae, S. agalactiae, S. pyogenes, S. pneumoniae and against all the tested fungal strains. In addition, E. odorata oil showed the most cytotoxic effect. However, the best antiviral activity appeared with E. bicostata. Virus pretreatment with E. bicostata essential oil showed better antiviral activity (IC50 = 0.7 mg/ml, SI = 22.8) than cell-pretreatment (IC50 = 4.8 mg/ml, SI = 3.33). The essential oil of E. astringens showed antiviral activity only when incubated with virus prior to cell infection. This activity was dose-dependent and the antiviral activity diminished with the decreasing essential oil concentration.

Correlation Between Chemical Composition and Antibacterial Activity of Essential Oils from Fifteen Eucalyptus Species Growing in the Korbous and Jbel Abderrahman Arboreta (North East Tunisia)

The essential oils of fifteen Eucalyptus species harvested from the Jbel Abderrahman and Korbous arboreta (North East Tunisia) were screened for their antibacterial activities by the agar disc diffusion method. Eighteen major components as identified by GC/FID and GC/MS were selected for a study of the chemical and biological activity variability. The main one was 1,8-cineole, followed by spathulenol, trans-pinocarveol, α-pinene, p-cymene, globulol, cryptone, β-phellandrene, viridiflorol, borneol, limonene and isospathulenol. The chemical principal component analysis identified five species groups and subgroups, where each group constituted a chemotype, however that of the values of zone diameter of the inhibition (zdi) identified six groups of Eucalyptus oils, characterized by their antibacterial inhibition ability. The strongest activity was shown by E. platypus oil against Enterococcus faecalis and by E. lamannii oil against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. A correlation between the levels of some major components and the antibacterial activities was observed.

Leaf Essential Oil of Juniperus oxycedrus L. (Cupressaceae) Harvested in Northern Tunisia: Composition and Intra‐Specific Variability

The essential oil composition of leaves of 60 individual trees of Juniperus oxycedrus L. growing in four locations in Tunisia harvested in three different seasons were investigated by GC and GC/MS. Seventy compounds were identified in the oils, and a relatively high variation in their contents were found. All the oils were dominated by terpenic hydrocarbons, with α‐pinene (27.35–58.03%) as the main component, followed by geranyl acetone (13; 1.96–7.14%), 13‐epimanoyl oxide (16; 1.35–6.95%), and eudesma‐4(15),7‐dien‐1‐ol (11; 1.39–4.18%). The 18 major oil components were processed by hierarchical clustering and principal component analysis (PCA) allowing to establish four groups, one divided into two subgroups, of populations according to the location and season of harvest. Their oils were differentiated by one compound or more, showing a clear seasonal and geographical polymorphism in their chemical composition allowing the identification of specific chemotypes. The pattern of geographic variation in the essential oil composition indicated that the oils of the populations from the continental site (Makthar) were clearly distinguished from those of the littoral localities (Tabarka, Hawaria, and Rimel).

Seasonal and Geographical Influences on the Chemical Composition of Juniperus phoenicea L. Essential Oil Leaves from the Northern Tunisia

The essential‐oil composition of 60 individual trees of Juniperus phoenicea L. from four Tunisian populations in three different periods were investigated by GC and GC/MS analyses. 59 Compounds were identified in the oils, and a relatively high variation in their contents was found. All the oils were dominated by the terpenic hydrocarbon fraction, and the main component was α‐pinene (20.28–40.86%). The results of the oil compositions were processed by hierarchical clustering and principal component analysis (PCA) allowing establishing four groups of essential‐oils differentiated by one compound or more. Pattern of geographic variation in essential‐oil composition indicated that individuals from the continental site (Makthar) were clearly distinguished from those from littoral localities (Tabarka, Hawaria, and Rimel).

Chemical composition of the essential oils of the berries of Juniperus oxycedrus L. ssp. rufescens (L. K.) and Juniperus oxycedrus L. ssp. macrocarpa (S. & m.) Ball. and their antioxidant activities.

This study is outlined to probe the chemical composition of essential oil and in vitro antioxidant activity of Juniperus oxycedrus ssp. macrocarpa (S. & m.) Ball. and Juniperus oxycedrus L. ssp. rufescens (L. K.) berries, collected from four sites, according to their maturity phase. The chemical composition of the hydrodistilled essential oil was analysed by GC-MS. Forty-eight compounds were identified, accounting for approximately 79.8–98.9% of the oil. The main constituents were α-pinene, germacrene D, myrcene, abietadiene and cis-calamenene, their mean percentage vary according to their phenological stage. The antioxidant activity of the samples was determined by the ABTS and DPPH radical scavenging activities. Hawaria essential oil extracted from mature berries showed the highest antioxidant capacity.

Chemical composition and antioxidant activity of the essential oil of Juniperus phoenicea L. berries

This study is designed to examine the chemical composition and antioxidant activity of the essential oil of Juniperus phoenicea L. ripe and unripe berries. GC and GC/MS analyses resulted in the detection of 42 components representing approximately 96.50–99.57% of the oils. Major components of the oils were α-pinene (58.61–77.39%), camphene (0.67–9.31%), δ-3-carene (0–10.01%) and trans-verbenol (0–5.24%). Antioxidant activities were determined by two different test systems, DPPH and ABTS radical scavenging activities. In both systems ripe berries exhibited better activity potential than the unripe ones.

Variabilité phénotypique de quelques populations de Pourpier (Portulaca oleracea L.) en Tunisie

Abstract The phenotypic diversity of four purslane populations, one was grown in green house and three are spontaneous, was estimated by the analyses of 19 morphological characters. The discriminante (DISC) analyse performed on the chosen characters has shown a strong interpopulation heterogeneity as well as between the cultivated population and the spontaneous one in one hand, as between the spontaneous populations in the other hand. This analyse has shown the presence of two varieties: Portulaca oleracea subsp. sylvestris (DC.) Celak., distinguished by its prostate, reddish and fleshy stems, and Portulaca oleracea subsp. sativa (Haw.) Celak., characterized by its taller upright growth habit and larger leaves and seeds. This results suggest large differences between the cultivated and the spontaneous plant as a consequence of different soil, temperature and nutrition conditions under green house, but also genetic diversity is expected among some spontaneous populations.

Variability in antimicrobial activity of latex from two varieties of Ficus carica

Laboratoire de Génétique, Biodiversité et Valorisation des Bio ressources (UR 03ES09), Institut Supérieur de Biotechnologie, 5000 Monastir, Tunisie. Laboratoire des Maladies Transmissibles et Substances Biologiquement Actives, Faculté de Pharmacie, 5000 Monastir, Tunisie. Laboratoire U.R. Agro biodiversité, Département des sciences Horticoles Institut Supérieur Agronomique, 4042, Tunisie. Laboratoire de Botanique et cryptogamie, Faculté de Pharmacie Besançon, 25000 cedex, France. Laboratoire de Chimie, 03/UR/1202, Faculté de Médecine Dentaire, 5000 Monastir, Tunisie. Laboratoire de Pharmacognosie et phytothérapie, Faculté de pharmacie, 5000 Monastir, Tunisie

INTRASPECIFIC VARIATION AND MORPHOMETRIC ANALYSIS OF Juniperus phoenicea L. BRANCHES AND CONES FROM TUNISIA

The intra- and inter populational geographic variation of eight distant populations of Juniperus phoenicea L. originating from Tunisia was examined biometrically on the basis of morphological-key characters of branches and cones. Seven and eight qualitative and quantitative (measured) traits of each branches and cones were studied on 45 and 29 vouchers, respectively. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) of euclidean distances were performed to verify the hypothesis of geographic differentiation and for the existence of two J. phoenicea L. subspecies. The sampled populations differed significantly from one another, while the intra-populational variation was lower. Two major groups emerged on the PCA and HCA results, separating the continental populations from the coastal ones. Compared to the morphological traits of J. phoenicea subspecies in the literature and the basic flora, we confirm the existence of two J. phoenicea taxa: J. phoenicea ssp. turbinata was the reported from the coastal sites and J. phoenicea ssp. phoenicea located in the continental ones.