Imed Cheraif

Chemical composition and antibacterial, antifungal and antioxidant activities of the flower oil of Retama raetam (Forssk.) Webb from Tunisia

The chemical composition of the essential oils obtained by hydrodistillation from the flowers of Retama raetam (Forssk.) Webb cultivated in Tunisia was determined by GC and GC/MS analysis. A total of 50 components representing 98.58% of the oil were identified: nonanal (35.75%), α-humulene (29.29%), acetaldehyde (7.84%), linalool (5,62%), myrcene (3.38%), tridecanal (2.21%), β-caryophyllene (1.79%), α-terpinyl acetate (1.46%), terpinolene (1.26%) and methyl anthranilate (1.06%) were found to be the major components. The oil was evaluated for antibacterial and antifungal activities using a microdilution assay against some bacteria and yeasts. The minimal inhibitory concentrations (MIC) of the essential oil varied between 0.625 and 5 mg mL−1 and the minimum bactericidal concentrations (MBC) were superior to 5 mg mL−1 of oil for most strains. The antioxidant potential of the essential oil was evaluated using the 2,2′-diphenyl-1-picrylhydrazyl free radical scavenging method. The essential oil possesses good antioxidant properties (IC50 = 0.800 mg mL−1). The results may suggest that the flower oil of R. raetam possesses compounds with antibacterial, antifungal and antioxidant capacities, and thus the oil can be explored as a natural preservative ingredient in food and/or pharmaceutical preparations.

Chemical Composition and Antimicrobial Activity of Essential Oils from Scabiosa arenariaForssk. Growing Wild in Tunisia

The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk. were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC‐FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α‐thujone (34.39%), camphor (17.48%), and β‐thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α‐thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α‐thujone (9.5%) were identified as the major compounds.

trans-Fatty acid isomers in two sesame (Sesamum indicum L.) seed byproducts under processing.

The present study has been inspired by the growing need for rigorously controlling the nutritional quality and safety of food products. The impact of application in the food industry on fatty acids composition, trans-fatty acids (TFAs), and conjugated linoleic acid (CLA) profiles were investigated in a highly consumed candy byproduct of sesame seed (chamia) in comparison to fresh sesame seed oil (SSO) and heated SSO under simulated frying experiments. The effect of treatment on SSO was studied by determining the TFA and CLA changes. Results showed significant differences between the two byproducts in TFA and CLA amounts. Total TFAs were found to be significantly higher in chamia than fresh SSO (1.31 versus 0.066%, respectively; p < 0.05) and even higher than all heated SSO from 2 to 10 h at 180 °C (1.31 versus 0.33%, respectively; p < 0.05). A significant linear relationship was found between trans-monounsaturated fatty acid (MUFA), trans-polyunsaturated fatty acid (PUFA), and total TFA and the time of processing, with a correlation coefficient (R(2)) greater than 0.9 for TFA and PUFA, with a higher correlation assigned to PUFA (r = 0.988; p < 0.001), followed by TFA (r = 0.959; p < 0.01) and MUFA (r = 0.844; p < 0.05). Principal component analysis of the fatty acid (FA) profiles showed discrimination between chamia and both fresh and heated SSO. A high stability of SSO against isomerization reactions as compared to their chamia sample counterpart has been noted. These findings suggest that the food industry engenders relatively higher changes in fatty acid configurations than the frying process.

Chemical composition, antibacterial and antifungal activities of flowerhead and root essential oils of Santolina chamaecyparissus L., growing wild in Tunisia

The antimicrobial properties of essential oil from various Santolina species have not been investigated enough in the previous studies dealing with the biological activities of medicinal plants. In Tunisia, Santolina chamaecyparissus L. (Asteraceae) is the only Santolina species recorded and is used as vermifuge and emmenagogue. The chemical composition, antibacterial and antifungal properties of essential oils from the flowerheads and roots of spontaneous S. chamaecyparissus growing in Tunisia and the chemical composition which leads to the Tunisian chemotype are investigated here for the first time. Essential oils isolated by hydro distillation from flowerheads and roots of S. chamaecyparissus were analyzed by GC and GC/MS. Two methods served for antimicrobial assays of the essential oils: diffusion in a solid medium and micro-well dilution assay. Antifungal tests were carried out by the agar incorporation method. Sixty-seven constituents were identified from the essential oil of the flowerhead. The major constituents were: 1,8-cineole and β-eudesmol. Two non identified compounds were present at the highest concentration in root oil. Flowerhead oil was characterized by high contents in monoterpenes and sesquiterpenes oxygenated compounds. The flowerhead essential oil demonstrated potent of antibacterial properties against Pseudomonas aeruginosa ATCC and Enterococcus faecalis ATCC, with MIC of 0.625 μg/ml. These findings demonstrate that the flowerhead essential oils of S. chamaecyparissus have excellent antibacterial properties and for this reason they could contribute to decrease the problem of microbial resistance to antibiotics.

Composition and Antimicrobial Activities of Essential Oils From the Aerial Parts and Flowers of Thymus hirtus W. Growing in Tunisia

Abstract The chemical composition of essential oils isolated from fresh flowers and aerial parts of Thymus hirtus Willd was analyzed using GC and GC/MS. Forty-six components were identified in the oil of each organ. Camphor occurred as the major constituent of the aerial part oil, while α-pinene was the most notably dominating compound in the flower oil. Biological activities of the indicated oils were evaluated against eight bacteria, nine phytopathogenic, and 15 human pathogenic fungi.

Correlations between Peripheral Trans Fatty Acids, Lipid PeroxidationMarkers and Cognition in Dementia

Relationships between alterations in lipid metabolism, oxidative stress and dementia are widely suspected. In order to determine the impact of trans fatty acids (TFA) on oxidative stress and lipid peroxidation in demented patients, plasma and red blood cells (RBCs) were collected from patients diagnosed with Alzheimer’s diseases (AD) or vascular dementia, and from an age-matched healthy control group of elderly individuals. Fatty acid profiles were established by gas chromatography on matched plasma and RBCs. Lipid peroxidation biomarkers (malondialdehyde (MDA) and conjugated dienes (CD)) were analyzed using spectrophotometric methods. The severity of dementia was evaluated with the Mini-Mental State Examination (MMSE). An accumulation of MDA and CD and of several TFA was observed in the plasma and RBCs of demented patients. In the plasma and RBCs, positive correlations were found between CD and TFA: C18:1 trans 11 in AD patients; sum of TFA and C18:2 cis 9 trans 12 in patients with vascular dementia (P<0.05). In RBCs, a negative correlation was observed between C18:1 trans 11 and MMSE scores in vascular dementia. Altogether, our data support the existence of relationships between TFA, oxidative stress, lipid peroxidation and the risk of cognitive disorders.