Although bioactivities of Olea europaea (OE) have been widely described, most of them were related to its methanolic extracts or its essential oils, While data related to aqueous extracts still very scarce. Thus, in this study, the phytochemical composition, the antioxidant activity, the cytotoxic potential, and the allelopathic potential of aqueous leaf extracts from two varieties of Olea europaea were investigated and compared. High‐performance liquid chromatography (HPLC) was used to identify and quantify the constituents of the tested plants, and spectrophotometric methods to evaluate antioxidant activities. The cytotoxic potential was investigated using murine oligodendrocytes (158N) while germination seeds’ test was used for allelopathic activity. HPLC analysis showed the presence of 10 phenolic compounds in both extracts. Chemlali variety showed the highest antioxidant and allelopathic activities. Regarding the cytotoxicity effect, a significant increase in cell viability was observed with both of our extracts compared to untreated cells. These results confirm that aqueous extracts from OE produce a range of substances with potential antioxidant, antifungal, and allelopathic effects without toxic effects. Thus, they could be used as an alternative of chemical compounds.
T. capitatus is widely used in traditional medicine in Tunisia. The main goal of this study was to evaluate the phytochemical composition, the fatty acids profile, the antioxidant, antibacterial, and antifungal activities as well as the cytotoxic potential of the essential oil (EO) of this plant. The identification and the quantification of the different constituents of the tested EO was determined by gas chromatography–mass spectrometry (GC-MS). Antioxidant activities were evaluated by spectrophotometric methods and chemical tests. HCT 116 cells were used to evaluate the cytotoxic effect of the EO. The microdilution method was conducted to evaluate the antibacterial activity. Poisoned food method was used to test the antifungal activities against fungi species such Aspergillus niger and Aspergillus flavus. The EO presented several components, mainly monoterpenes. Results revealed that T. capitatus EO is not cytotoxic and showed excellent antioxidant activity with a dose dependent manner. Regarding antimicrobial activity, T. capitatus EO was efficient against all tested bacteria and fungi.
1 April 2014 in Antimicrobial Agents and Chemotherapy
The rising number of infections caused by biofilm formation and the difficulties associated with their treatment by conventional antimicrobial therapies have led to an intensive search for novel antibiofilm agents. Dermaseptins are antimicrobial peptides with a number of attractive properties that might offer alternative therapies against resistant microorganisms. In this study, we synthesized a set of dermaseptin-derived peptides and evaluated their activities against Gram-positive and Gram-negative bacterial biofilm formation. All dermaseptin-derived peptides demonstrated concentration-dependent antibiofilm activities at microgram concentrations, and their activities were dependent on the nature of the peptides, with the highest levels of activity being exhibited by highly charged molecules. Fluorescent binding and confocal microscopy demonstrated that dermaseptin K 4 S 4 , a substituted derivative of the native molecule S 4 , significantly decreased the viability of planktonic and surface-attached bacteria and stopped biofilm formation under dynamic flow conditions. Cytotoxicity assays with HeLa cells showed that some of the tested peptides were less cytotoxic than current antibiotics. Overall, these findings indicate that dermaseptin derivatives might constitute new lead structures for the development of potent antibiofilm agents.
Globularia alypum L. (GA) is a Mediterranean plant of the Globulariaceae family which is widely used in traditional Tunisian medicine. The main goal of this study was to evaluate the phytochemical composition, antioxidant, antibacterial, and antibiofilm activities, and the antiproliferative potential of different extracts of this plant. The identification and the quantification of the different constituents of extracts were determined using gas chromatography–mass spectrometry (GC-MS). The antioxidant activities were evaluated using spectrophotometric methods and chemical tests. The antiproliferative study was based on the use of colorectal cancer SW620 cells, including an antibacterial assessment with the microdilution method and analysis of the antibiofilm effects via the crystal violet assay. All extracts presented several components, mainly sesquiterpenes, hydrocarbon, and oxygenated monoterpenes. The results revealed that the maceration extract had the most important antioxidant effect (IC50 = 0.04 and 0.15 mg/mL), followed by the sonication extract (IC50 = 0.18 and 0.28 mg/mL). However, the sonication extract demonstrated significant antiproliferative (IC50 = 20 µg/mL), antibacterial (MIC = 6.25 mg/mLand MBC > 25 mg/mL), and antibiofilm (35.78% at 25 mg/mL) properties against S. aureus. The results achieved confirm the important role of this plant as a source of therapeutic activities.
29 April 2020 in Current Pharmaceutical Biotechnology
Background: The plant species Thymus algeriensis (TA); Thymus capitatus (TC) and Rosmarinus officinalis (RO), are widely used in traditional medicine in Tunisia. The bioactivities of their essential oils have been also reported previously. The main objective of this work was to assess the phytochemical composition, the antioxidant activity, cytotoxic potential and the antibacterial, antifungal, of the essential oil (EO) of these plants. Methods: Gas chromatography–mass spectrometry (GC-MS) was used to identify and quantify the constituents of the tested EO, chemical tests and spectrophotometric methods were used for antioxidant activities and for the screening, the quantification of phytochemicals. The cytotoxic potential of the EO was checked using HCT 116 cultures. Extracts were evaluated for their antibacterial potential by the microdilution method. Antifungal activities were tested using the Poisoned food method against: Aspergillus niger and Aspergillus flavus. Results: The EO of tested plants presented several components, mainly monoterpenes and sesquiterpenes. Results revealed that T. capitatus EO is not toxic comparing to the other tested samples. Phenolic compounds were detected and this EO showed excellent antioxidant activity presenting dose dependent relationship. Regarding antimicrobial activity, T. capitatus EO, also had the highest inhibition against all tested bacteria and fungi. Conclusions: This study showed the importance of the bioactivities (antioxidant, antimicrobial, and safety potential) of EOs of the plant species TC, RO, and TA used in traditional medicine.