Green synthesis and characterization of silver nanoparticles from Ducrosia flabellifolia Boiss. aqueous extract: Anti-quorum sensing screening and antimicrobial activities against ESKAPE pathogens.

Biosynthesis of silver nanoparticles using natural compounds derived from plant kingdom is currently used as safe and low-cost technique for nanoparticles synthesis with important abilities to inhibit multidrug resistant microorganisms (MDR). ESKAPE pathogens, especially MDR ones, are widely spread in hospital and intensive care units. In the present study, AgNPs using Ducrosia flabellifolia aqueous extract were synthesized using a reduction method. The green synthesized D. flabellifolia-AgNPs were characterized by UV-Vis spectrophotometer, Scanning electron microscopy (SEM), and X-ray diffraction assays. The tested D. flabellifolia aqueous extract was tested for its chemical composition using Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS). Anti-quorum sensing and anti-ESKAPE potential of D. flabellifolia-AgNPs was also performed.  Results from LC-ESI-MS technique revealed the identification of chlorogenic acid, protocatechuic acid, ferulic acid, caffeic acid, 2,5-dihydroxybenzoic acid, and gallic acid as main phytoconstituents. Indeed, the characterization of newly synthetized D. flabellifolia-AgNPs revealed spherical shape with mean particle size about 16.961±2.914 nm. Bio-reduction of silver was confirmed by the maximum surface plasmon resonance of D. flabellifolia-AgNPs at 430 nm. Newly synthetized D. flabellifolia-AgNPs were found to possess important anti-ESKAPE activity with low minimal inhibitory concentrations (MICs) ranging from 0.078 to 0.312 mg/mL, and low minimal bactericidal concentrations (MBCs) varying from 0.312 to 0.625 mg/mL. Moreover, D. flabellifolia-AgNPs were active against Candida utilis ATCC 9255, C. tropicalis ATCC 1362, and C. albicans ATCC 20402 with high mean diameter of growth inhibition at 5 mg/mL, low MICs, and minimal fungicidal concentrations values (MFCs). The newly synthetized D. flabellifolia-AgNPs were able to inhibit violacein production in Chromobacterium violaceum, pyocyanin in Pseudomonas aeruginosa starter strains.  Hence, the newly synthesized silver nanoparticles using D. flabellifolia aqueous extract can be used as an effective alternative to combat ESKAPE microorganisms. These silver nanoparticles can attenuate virulence of Gram-negative bacteria by interfering with the quorum sensing system and inhibiting cell-to-cell communication.

In Vitro Screening of Antimicrobial and Anti-Coagulant Activities, ADME Profiling, and Molecular Docking Study of Citrus limon L. and Citrus paradisi L. Cold-Pressed Volatile Oils.

Citrus, which belongs to the Rutaceae family, is a very widespread genus in the Mediterranean Basin. In Tunisia, various parts of these spontaneous or cultivated plants are used in common dishes or in traditional medicine. The purpose of this work was to investigate C. limon and C. paradisi essential oil (EO). The samples were studied for their chemical composition using SPME/MS, as well as their antibacterial and antifungal activities. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) methods were used to evaluate the anticoagulant potentialities. The obtained results show that both essential oils are rich in monoterpenes hydrocarbons, whereby limonene is the main compound in C. paradisi EO (86.8%) and C. limon EO (60.6%). Moreover, C. paradisi EO contains ß-pinene (13.3%), sabinene (2.2%) and α-pinene (2.1%). The antibacterial assay of the essential oils showed important bactericidal and fungicidal effects against all strains tested. In fact, the MICs values of C. limon EO ranged from 0.625 to 2.5 mg/mL against all Gram-positive and Gram-negative bacteria, and from 6.25 to 12.5 mg/mL for Candida spp. strains, while C. paradisi EO was more active against all bacteria with low MICs values ranging from 0.192 to 0.786 mg/mL, and about 1.5 mg/mL against Candida species. Both tested Citrus EOs exhibited interesting anticoagulant activities as compared to heparin. The molecular docking approach was used to study the binding affinity and molecular interactions of all identified compounds with active sites of cytidine deaminase from Klebsiella pneumoniae (PDB: 6K63) and the C (30) carotenoid dehydrosqualene synthase from Staphylococcus aureus (PDB: 2ZCQ). The obtained results show that limonene had the highest binding score of -4.6 kcal.mol-1 with 6K63 enzyme, and -6.7 kcal.mol-1 with 2ZCQ receptor. The ADME profiling of the major constituents confirmed their important pharmacokinetic and drug-like properties. Hence, the obtained results highlight the potential use of both C. limon and C. paradisi essential oils as sources of bioactive compounds with antibacterial, antifungal, and anti-coagulant activities.

Antimicrobial Potential of Pithecellobium dulce Seed Extract against Pathogenic Bacteria: In Silico and In Vitro Evaluation.

Clinical multi-drug-resistant bacteria continue to be a serious health problem. Plant-derived molecules are an important source of bioactive compounds to counteract these pathogenic bacteria. In this paper, we studied the chemical composition of the methanol (80%) extract from Pithecellobium dulce seed (Hail, Saudi Arabia) and its ability to inhibit the growth of clinically relevant multi-drug-resistant bacteria. Molecular docking analysis was performed to predict the best compounds with low binding energy and high affinity to interact with two Staphylococcus aureus receptors. Data showed that P. dulce extract is a rich source of D-turanose (55.82%), hexadecanoic acid (11.56%), indole-1-acetic acid (11.42%), inositol (5.78%), and octadecanoic acid (4.36%). The obtained extract showed antibacterial activity towards tested clinical bacterial strains with MIC values ranging from 233 mg/mL for Acinetobacter baumannii to 300 mg/mL for S. aureus and Escherichia coli. Turanose interaction has resulted in -7.4 and -6.6 kcal/mol for 1JIJ and 2XCT macromolecules, while inositol showed energy values (-7.2 and -5.4 kcal/mol) for the same receptors. Multiple identified compounds showed desirable bioavailability properties indicating its great potential therapeutic use in human. Overall, current investigation highlights the possible use of P. dulce extract as a valuable source for drug development against pathogenic drug-resistant bacteria.

Chemical Composition of Ducrosia flabellifolia L. Methanolic Extract and Volatile Oil: ADME Properties, In Vitro and In Silico Screening of Antimicrobial, Antioxidant and Anticancer Activities.

In the present study, the chemical composition of the volatile oil and methanolic extract from Ducrosia flabellifolia Boiss. was investigated. The antimicrobial, antioxidant, and anticancer activities of the methanolic extract from D. flabellifolia aerial parts were screened using experimental and computational approaches. Results have reported the identification of decanal (28.31%) and dodecanal (16.93%) as major compounds in the essential oil obtained through hydrodistillation. Farnesyl pyrophosphate, Methyl 7-desoxypurpurogallin-7-carboxylate trimethyl ether, Dihydro-Obliquin, Gummiferol, 2-Phenylaminoadenosine, and 2,4,6,8,10-dodecapentaenal, on the other hand, were the dominant compounds in the methanolic extract. Moreover, the tested extract was active against a large collection of bacteria and yeast strains with diameter of growth inhibition ranging from 6.67 ± 0.57 mm to 17.00 ± 1.73 mm, with bacteriostatic and fungicidal activities against almost all tested microorganisms. In addition, D. flabellifolia methanolic extract was dominated by phenolic compounds (33.85 ± 1.63 mg of gallic acid equivalent per gram of extract) and was able to trap DPPH• and ABTS•+ radicals with IC50 about 0.05 ± 0 mg/mL and 0.105 ± 0 mg/mL, respectively. The highest percentages of anticancer activity were recorded at 500 µg/mL for all cancer cell lines with IC50 about 240. 56 µg/mL (A-549), 202.94 µg/mL (HCT-116), and 154.44 µg/mL (MCF-7). The in-silico approach showed that D. flabellifolia identified compounds bound 1HD2, 2XCT, 2QZW, and 3LN1 with high affinities, which together with molecular interactions and the bond network satisfactorily explain the experimental results using antimicrobial, antioxidant, and anticancer assays. The obtained results highlighted the ethnopharmacological properties of the rare desertic D. flabellifolia plant species growing wild in Hail region (Saudi Arabia).

LC-ESI/MS-Phytochemical Profiling with Antioxidant, Antibacterial, Antifungal, Antiviral and In Silico Pharmacological Properties of Algerian Asphodelus tenuifolius (Cav.) Organic Extracts.

Asphodelus tenuifolius Cav. (A. tenuifolius) is a medicinal plant with a long history of traditional use to treat ailments. In this study, total phenolic and flavonoid content evaluation using LC-ESI/MS analysis and various biological activities (antioxidant, antibacterial, antifungal, antiviral and cytotoxicity) of organic extracts from the aerial parts of A. tenuifolius were analyzed. ADME tools were used to predict the potential of the identified compounds from the most potent extract as specific drugs. As shown, LC-ESI/MS results of chloroformic extract allowed the tentative identification of 12 compounds. Chloroformic extract was rich in polyphenols and flavonoids and exhibited the highest antioxidant activity given by DPPH (IC50 = 25 µg/mL) as compared to the BHT standard (11.5 µg/mL) and ß-carotene bleaching assays (IC50 = 95.692 µg/mL). Antibacterial activity results showed that chloroformic extract has a highest activity against Gram-positive and -negative bacteria, especially against Salmonella Typhimurium DT104 (IZ = 19.3 mm, MIC = 18.75 mg/mL, MBC = 37.5 mg/mL). The MBC/MIC ratio was evaluated to interpret the activity that was bacteriostatic rather than bactericidal. Conversely, weaker antifungal activity was registered, and no antiviral activity was observed for all extracts against Herpes Simplex Virus type 2 and Coxsakievirus B-3 viruses. Cytotoxic activity on VERO cell line results revealed that butanol extract was not toxic, with CC50 value of 1430 µg/mL, while chloroformic extract showed moderate cytotoxicity. Additionally, in silico studies performed proved promising pharmacokinetic and drug-likeness properties of the main compounds from the chloroformic extract. Taken together, this work highlights the potent bioactivity and acceptable drug-likeness of this plant, which supports its further preclinical development.

Bioactivities and in silico study of Pergularia tomentosa L. phytochemicals as potent antimicrobial agents targeting type IIA topoisomerase, TyrRS, and Sap1 virulence proteins.

Pergularia tomentosa L. (P. tomentosa) has been largely used in Tunisian folk medicine as remedies against skin diseases, asthma, and bronchitis. The main objectives of this study were to identify phytochemical compounds that have antioxidant and antimicrobial properties from the stem, leaves, and fruit crude methanolic extracts of P. tomentosa, and to search for tyrosyl-tRNA synthetase (TyrRS), topoisomerase type IIA, and Candidapepsin-1 (SAP1) enzyme inhibitors through molecular docking study. Phytochemical quantification revealed that fruit and leaves extracts displayed the highest total flavonoids (582 mg QE/g Ex; 219 mg QE/g Ex) and tannins content (375 mg TAE/g Ex; 216 mg TAE/g Ex), also exhibiting significant scavenging activity to decrease free radicals for ABTS, DPPH, ß-carotene, and FRAP assay with IC50 values (> 1 mg/mL). Additionally, promising antimicrobial activities towards different organs have been observed against several bacteria and Candida strains. From the liquid chromatography-mass spectrometry (LC-MS) analysis, five polyphenolic compounds, namely digitoxigenin, digitonin glycoside and calactina in the leaves, kaempferol in the fruit, and calotropagenin in the stems, were identified. They were also analyzed for their drug likeliness, based on computational methods. Molecular docking study affirmed that the binding affinity of calactin and actodigin to the active site of TyrRS, topoisomerase type IIA, and SAP1 target virulence proteins was the highest among the examined dominant compounds. Therefore, this study indicated that P. tomentosa methanolic extracts displayed great potential to become a potent antimicrobial agent and might be a promising source for therapeutic and nutritional functions. These phytocompounds could be further promoted as a candidate for drug discovery and development.

Antioxidant Activities of a New Chemotype of Piper cubeba L. Fruit Essential Oil (Methyleugenol/Eugenol): In Silico Molecular Docking and ADMET Studies.

Piper cubeba L. fruit is an important species used in folk medicine for different types of pains such as rheumatism, chills, flu, colds, muscular aches, and fever. This study examines the chemical constituents, antioxidant activity, and potential inhibitory effect against human peroxiredoxin 5, a key enzyme of P. cubeba essential oil from fruits. Using gas chromatography coupled with mass spectrometry (GC-MS), the principal components were methyleugenol (41.31%) and eugenol (33.95%), followed by (E)-caryophyllene (5.65%), p-cymene-8-ol (3.50%), 1,8-cineole (2.94%), and α-terpinolene (1.41%). Results showed similar scavenging activity via 2,2-diphenyl-1-picrylhydrazyl DPPH radical scavenging activity (IC50 = 110.00 ± 0.08 µg/mL), as well as very potent antioxidant activity against both ferric reducing/antioxidant power (FRAP) (106.00 ± 0.11 µg/mL) and ß-carotene bleaching (IC50 = 315.00 ± 2.08 µg/mL) assays when compared to positive butylated hydroxytoluene and ascorbic acid. The molecular docking approach has also been performed to screen the antioxidant activities of the major and potent compounds against human protein target peroxiredoxin 5. Results showed good binding profiles and attributed the strongest inhibitory activity to ß-caryophyllene oxide (-5.8 kcal/mol), followed respectively by isocembrol and α-selinene (-5.4 kcal/mol), and viridiflorol (-5.1 kcal/mol). Furthermore, ADME (absorption, distribution, metabolism and excretion)-related physicochemical and pharmacokinetic properties have been assessed and support our in vitro findings. This work demonstrates the powerful antioxidant potency of cubeba pepper and paves the way for the discovery and development of antioxidant agent with high potency.

Potential antidiabetic effect of ethanolic and aqueous-ethanolic extracts of Ricinus communis leaves on streptozotocin-induced diabetes in rats.

Recently, herbal drugs and their bioactive compounds have gained popularity in the management of diabetes mellitus (DM), which has become an epidemic disease all over the world and is especially prevalent in the Kingdom of Saudi Arabia (KSA). This study aimed to investigate the antidiabetic effect of ethanolic and aqueous-ethanolic extracts of wild Ricinus communis (R. communis) leaves in streptozotocin (STZ) induced diabetic rats. Diabetic rats were administered orally with the mentioned extracts at doses of 300 and 600 mg/kg/BW for 14 days, and the obtained results of different biochemical parameters were compared with normal control, diabetic control and standard drug glibenclamide (5 mg/kg/BW). The obtained results revealed a remarkable and significantly (P < 0.05) reverse effect of the body weight loss, observed when diabetic rats were treated with ethanol and aqueous-ethanol extracts at 300 mg/kg/BW. Administration of the ethanol extract at 600 mg/kg/BW significantly (P < 0.05) reduced the blood glucose level. A significant increase in the AST, ALT and ALP levels (P < 0.05) was observed in the diabetic control and in the experimental groups with glibenclamide which was also significantly (P < 0.05) lowered after treatment with extracts at special doses. Total proteins, albumin, total bilirubin, direct bilirubin, creatinine and urea were also investigated and compared to the corresponding controls. We showed that administration of R. communis extract generally significantly (P < 0.05) ameliorated the biochemical parameters of diabetic rats. Also, the changes in serum electrolyte profile were assessed and the results demonstrate that administration of extracts at concentration of 600 mg/kg/BW generally inhibits the alteration maintain their levels. The obtained data imply the hypoglycemic effects of this plant, which may be used as a good alternative for managing DM and therefore validating its traditional usage in KSA.

Cardiopreventive effect of ethanolic extract of Date Palm Pollen against isoproterenol induced myocardial infarction in rats through the inhibition of the angiotensin-converting enzyme.

The present study aimed to examine the putative preventive effect of the ethanolic extract Date Palm Pollen (DPP, Phoenix dactylifera L., family Arecaceae) on isoproterenol-induced myocardial infarction (MI) in rats. Twenty four rats were randomly divided into four groups including control. They were treated with DPP extract (400mg/kg) and clopidogrel (0.2mg/kg) for 7days followed by myocardial injury induction using subcutaneous isoproterenol (100mg/kg) with an interval of 24h for two days (6th and 7th day). Administration of isoproterenol exhibited indicative changes in the ECG pattern evidenced by significant elevation of ST-segment and cardiac injury markers viz.; troponin-T, creatine phosphokinase (CPK), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) by 315%, 71%, 64% and 170%, respectively as compared to control. Additionally, the angiotensin-converting enzyme (ACE) activity in plasma was increased by 33% associated to histological myocardial necrosis. However, pre-co-treatment with DPP extract improved the cardiac biomarkers injury, normalized cardiac function indices and prevented the ventricular remodeling process through inhibition of ACE activity by 34% and the inhibition of the generation of radical oxygen species. Extensive characterization of this DPP extract using LC-HRMS revealed numerous flavonoids and phenols compounds which could be endowed with cardiopreventive actions. Overall, these results proved that DPP extract has preventive effects on cardiac remodeling process.

Anti-microbial screening and cytotoxic activity of aerial part of Thymelaea hirsuta L. essential oil growing in south-west Tunisia.

This study aimed to investigate the antimicrobial and cytotoxic activities of essential oil isolated by the hydro-distillation of aerial parts of Thymelaea hirsuta. The antimicrobial activity of the oil was evaluated against eight bacterial and three fungal pathogenic strains. The results revealed that the essential oil exhibited a moderate-to-potent anti-microbial activity against all the microorganisms tested. Gram-positive bacteria were noted to be more sensitive to the oil than gram-negative bacteria and yeasts. In vitro cytotoxicity evaluation against HeLa cell lines showed that the essential oil exhibited moderate cytotoxicity on human tumor cells, with a high IC50 value of 175µg/mL. To the author's knowledge, this is the first study reporting on the antimicrobial and cytotoxic activities of Thymelaea hirsuta essential oil. Overall, the results indicate that the T. hirsuta essential oil has a number of attractive properties that might open new promising opportunities for the control or prevention of a wide range of microbial infections and cancers and can facilitate the use of essential oils as natural preservatives against spoilage microorganisms in food systems.

Essential oil of the leaves of Ricinus communis L.: in vitro cytotoxicity and antimicrobial properties.

BACKGROUND: The aim of the present study was to appraise the antimicrobial activity of Ricinus communis L. essential oil against different pathogenic microorganisms and the cytotoxic activity against HeLa cell lines. METHODS: The agar disk diffusion method was used to study the antibacterial activity of Ricinus communis L. essential oil against 12 bacterial and 4 fungi strains. The disc diameters of zone of inhibition (DD), the minimum inhibitory concentrations (MIC) and the concentration inhibiting 50% (IC50) were investigated to characterize the antimicrobial activities of this essential oil. The in vitro cytotoxicity of Ricinus communis L. essential oil was examined using a modified MTT assay; the viability and the IC50 were used to evaluate this test. RESULTS: The essential oil from the leaves of Ricinus communis L. was analyzed by GC-MS and bioassays were carried out. Five constituents of the oil were identified by GC-MS. The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against twelve bacteria and four fungi species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested with higher sensitivity for Bacillus subtilis, Staphylococcus aureus and Enterobacter cloacae. The cytotoxic and apoptotic effects of the essential oil on HeLa cell lines were examined by MTT assay. The cytotoxicity of the oil was quite strong with IC50 values less than 2.63 mg/ml for both cell lines. CONCLUSION: The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of Ricinus communis L., indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections.

The in-vitro evaluation of antibacterial, antifungal and cytotoxic properties of Marrubium vulgare L. essential oil grown in Tunisia.

BACKGROUND: In order to validate its antiseptic and anticancer properties with respect to traditional uses, we have screened for the first time the antimicrobial activity of aerial parts of M. vulgare L. essential oil against different pathogenic microorganisms and the cytotoxic activity against HeLa cell lines. METHODS: The agar disk diffusion method was used to study the antibacterial activity of M. vulgare essential oil against 12 bacterial and 4 fungi strains. The disc diameters of zone of inhibition (DD), the minimum inhibitory concentrations (MIC) and the concentration inhibiting 50% (IC50) were investigated to characterize the antimicrobial activities of this essential oil. The in vitro cytotoxicity of M. vulgare essential oil was examined using a modified MTT assay; the viability and the IC50 were used to evaluate this test. RESULTS: The antimicrobial activity of the essential oil was investigated in order to evaluate its efficacy against the different tested microorganisms. The present results results showed a significant activity against microorganisms especially Gram (+) bacteria with inhibition zones and minimal inhibitory concentration values in the range of 6.6-25.2 mm and 1120-2600 µg/ml, respectively, whereas Gram (-) bacteria exhibited a higher resistance. As far as the antifungal activity, among four strains tested, Botrytis cinerea exhibited the strongest activity with inhibition zones of 12.6 mm. However, Fusarium solani, Penicillium digitatum and Aspergillus niger were less sensitive to M. vulgare essential oil. About the citotoxicity assay, this finding indicate the capability of this essential oil to inhibited the proliferation of HeLa cell lines under some conditions with IC50 value of 0.258 µg/ml. CONCLUSION: This investigation showed that the M. vulgare essential oil has a potent antimicrobial activity against some Gram (+) pathogenic bacteria and Botrytis cinerea fungi. The present studies confirm the use of this essential oil as anticancer agent. Further research is required to evaluate the practical values of therapeutic applications.