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 ß-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.

Reversal of resistance in bacteria underlies synergistic effect of essential oils with conventional antibiotics.

The pervasive of bacterial resistance earnestly threaten the prevention and the treatment of infectious diseases. Therefore, scientific communities take precedence over development of new antimicrobial agents. The aim of the study was to determine antimicrobial potency of three North-African essential oils Pituranthos chloranthus, Teucruim ramosissimum and Pistacia lentiscus individually, and in combination with antibiotics, to inhibit the growth of highly resistant clinical pathogen. Bacteria clinically isolated from patients, subsequently, challenged to a panel of drugs to determine the antibiotic-resistance profiles. Drugs displaying clinically irrelevant CMI were subjected to further studies in order to rescue antibiotic actions. Singular activity of essential oils and activity when combined with an antibiotic was hence elucidated. The results obtained highlighted the occurrence of strong antibacterial potential of essential oils when administrated alone. In the interactive experiment essential oils were found highly effective in reducing the resistance of Methicillin-resistant Staphylococcus aureus to amoxicillin, tetracycline, piperacillin, ofloxacin and oxacillin and resistance of Acinetobacter baumannii to amoxicillin and to ofloxacin in interactive manner. Furthermore, the results proved synergism among essential oils and both antibiotics ofloxacin and novobiocin against the Extended-Spectrum Beta-Lactamase producing E. coli (ESBL). Time kill kinetics was performed with a combination of sub-inhibitory concentrations to confirm the efficiency and killing rate of the combination over time. Further, the hypothetical toxicity of essential oils against human keratinocytes HaCat and murine spleenocytes were examined. The chemical composition of essential oils was assessed by GC/MS analysis and the major constituents found were sabinene, limonene, terpinen-4-ol, and ß-eudesmol.

Extra virgin olive oil modulates brain docosahexaenoic acid level and oxidative damage caused by 2,4-Dichlorophenoxyacetic acid in rats.

Oxidative stress is an important pathomechanism of neurological disorders such as Alzheimer disease and Parkinson disease, cardiovascular disorders and many others. This study sought to verify whether extra-virgin olive oil (EVOO), lipophilic fraction (OOLF) and hydrophilic fraction (OOHF) exerted a brain protective effect against the oxidative stress caused by 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide at a dose of 5 mg/kg body weight. 2,4-D, EVOO and its fractions were administered to rats by gavages for four consecutive weeks. Oxidative stress was assessed by measuring brain lipid peroxide level, acetylcholinesterase (AChE), antioxidant enzyme activities and fatty acid composition. 2,4-D induced a decrease in both plasma and brain acetylcholinesterase activity and a rise in Brain TBARS (Thiobarbituric acid reactive substances) level and antioxidant enzyme activities compared with the control group. These changes were partly reversed by either EVOO or its fractions oral administration to 2,4-D treated rats. EVOO enhanced a neuroprotective effect evaluated by the restoration of brain fatty acid composition especially the level of docosahexaenoic acid (DHA). Our results indicate that EVOO exerts a neuroprotective activity against oxidative damage in brain induced by 2,4-D, which could be attributed to its antioxidative property.

Nutritional quality of fresh and heated Aleppo pine (Pinus halepensis Mill.) seed oil: trans-fatty acid isomers profiles and antioxidant properties.

Numerous studies have focused on trans fatty acids (TFA) technologically produced by partial hydrogenation of oils. However, TFA can also be present in fresh oils. For this reason, cis fatty acid (CFA), TFA and conjugated linoleic acid (CLA) of fresh and heated Aleppo pine seed oil (APSO) at frying temperature (180 °C) were evaluated and correlated with the antioxidant characteristics. Results showed that fresh APSO had a low oleic/linoleic ratio O/L (0.4). Total TFA in fresh APSO reached 1%. The predominant TFA was 18:2 n-6 (t9, t12) in both fresh and heated APSO. Individual TFA increased with significant differences (p < 0.05) with heating time. CLA occurred after 4 h and significantly increased (p < 0.05) accounting 10% of total TFA after 10 h. Total TFA are negatively correlated with α-tocopherol, γ-tocopherol (p < 0.05) and carotenoïds (p < 0.01) and positively correlated with remaining DPPH. Oil stability index (OSI) showed significant negative correlation with TFA (r = -0.925; p = 0.008). A principal component analysis (PCA) showed a clear discrimination between fresh and heated oils. Temperature, heating time, unsaturation degree and antioxidants are combined factors which significantly affect the isomerization rate and nutritional quality of APSO.

Chemical composition and antimicrobial activity of essential oils from Scabiosa arenaria Forssk: 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 ß-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. Furthermore, the isolated oils were tested against 16 Gram-positive and Gram-negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.

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 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%), alpha-humulene (29.29%), acetaldehyde (7.84%), linalool (5,62%), myrcene (3.38%), tridecanal (2.21%), beta-caryophyllene (1.79%), alpha-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 (IC(50) = 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.