Phytochemical Analysis and Evaluation of the Antioxidant, Antiproliferative, Antibacterial, and Antibiofilm Effects of Globularia alypum (L.) Leaves.

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.

Phytochemical Analysis and Assessment of Biological Properties of Essential Oils Obtained from Thyme and Rosmarinus Species.

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 also been 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 and quantification of phytochemicals. The cytotoxic potential of the EO was checked using HCT 116 cultures. The extracts were evaluated for their antibacterial potential by the microdilution method. Antifungal activities were tested using the Poisoned food technique against Aspergillus niger and Aspergillus flavus. RESULTS: The EO of tested plants presented several components, mainly monoterpenes and sesquiterpenes. The results revealed that T. capitatus EO is not toxic compared to the other tested samples. Phenolic compounds were detected and this EO showed excellent antioxidant activity presenting dosedependent relationship. Regarding antimicrobial activity, T. capitatus EO, also had the highest inhibition against all tested bacteria and fungi. CONCLUSION: 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.

Chemical composition, Fatty acids profile and Biological properties of Thymus capitatus (L.) Hoffmanns, essential Oil.

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.

Antioxidant, Antimicrobial and the Phenolic Content of Infusion, Decoction and Methanolic Extracts of Thyme and Rosmarinus Species.

BACKGROUND: The plant species Rosmarinus officinalis (RO), Thymus algeriensis (TA) and Thymus capitatus (TC) are widely used in traditional medicine in Tunisia. Their bioactivities have been reported before and particularly referred to their essential oils. The main objective of this work was to assess the phytochemical composition, the antioxidant activity, the antibacterial, antifungal, and cytotoxic potential of these 3 plants. METHOD: The High Performance Liquid Chromatography (HPLC), chemical tests and spectrophotometric methods were used for screening, quantification of phytochemicals and for antioxidant activities. Extracts were evaluated for antibacterial potential by the microdilution method. Antifungal activities were tested using the Poisoned food method against: Aspergillus niger and Aspergillus flavus. The cytotoxic potential of the plant extracts was checked using HCT 116 cultures. RESULTS: Results revealed that aqueous extracts are not toxic compared to the methanolic extracts. Phenolic compounds were detected and these extracts showed excellent antioxidant activity presenting dose-dependent relationship. For antibacterial potential, all tested strains are more sensitive to Thymus extracts than Rosmarinus extracts. However, for antifungal activities, only Rosmarinus extracts inhibited mycelial growth. HPLC analysis allowed the identification of ten compounds with the abundance of gallic acid. CONCLUSION: This study showed important bioactivities (antioxidant, antimicrobial, and safety potential) of the plant species RO, TA and TC used in traditional medicine.

In vitro activities of dermaseptins K4S4 and K4K20S4 against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa planktonic growth and biofilm formation.

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 K4S4, a substituted derivative of the native molecule S4, 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.

In vitro activity of dermaseptin S4 derivatives against genital infections pathogens.

OBJECTIVES: Sexually transmitted infections present a great risk to the reproductive health of women. Therefore, female-controlled vaginal products directed toward disease prevention are needed urgently. In the present study, efforts were made to evaluate the antimicrobial potency of dermaseptin DS4, an antimicrobial peptide derived from frog skin. To assess the structure-activity relationship between the native DS4 and their derivatives, a set of chemically modified peptides was synthesized and evaluated. METHODS: Different strains of bacteria and fungi were used to detect the antimicrobial activity of the new compounds. HeLa cultures were used to determine the safety of compounds towards their toxicity. RESULTS: All DS4 derivatives elicited concentration-dependent antimicrobial activity at micrograms concentrations (MIC values: 4 microg/mL-l mg/mL). K4S4(1-28) and K4S4(1-16)a were the most active peptides whereas S4(6-28) was the less one. The order was K4S4(1-28)>K4S4(1-16)a>S4a>S4>S4(6-28). In cytotoxicity assay, some compounds were found to be significantly safer than current antibiotics. Our data also show that increasing the number of positive charges of the peptide resulted in a reduced cytotoxicity without affecting the antimicrobial effect. CONCLUSIONS: This study indicates that dermaseptins are antimicrobial molecules that deserve to be tested as topical microbicide with useful associated activities that can add to their prophylaxis, safety and effectiveness.

Spermicidal activity of dermaseptins.

OBJECTIVE: The present study was undertaken to elucidate the spermicidal efficacy of two synthetic antimicrobial peptides, dermaseptin (DS1 and DS4). METHODS: Twenty samples of fresh semen were obtained from patients aged between 23 and 35 years. The ability of DS to kill sperm was evaluated by the Sander-Cramer test under in vitro conditions. RESULTS: The data showed that sperm motility was inhibited with various concentrations of DS at different intervals ranging from 2 to 240 min. The effective 100% inhibitory concentration (EC(100)) of DS4 in 2 min during the sperm immobilization assay was 100 microg/mL whereas the sperm immobilization of EC(100) of DS1 was 200 microg/mL. The presence of 0.1% chelating agent ethylenediaminetetraacetic acid (EDTA) reduced the EC(100) of DS4 to 10 microg/mL whereas less than a two-time enhancement in DS1 activity was observed upon combination with EDTA. The action of DSs on sperm motility was observed to be dose dependent. Supplementation with pentoxifylline and that with calcium are known to enhance the motility of sperm but they did not prevent the spermicidal action of DSs. CONCLUSION: This present study indicates that DS is an effective agent to kill sperm. In view of this fact, it is suggested that DS4 has antibacterial, antiviral, antifungal and potentially spermicidal activities and could be a potent vaginal contraceptive.