The essential oil (EO) extracted from fresh flowers of Solenanthus tubiflorus Murb. growing in Tunisia was analysed by GC/MS and its chemical composition was reported for the first time. Seventy-two compounds were identified, with 3-carene (19.57%), estragole (17.75%), bicyclo[3.1.0]hexane, 4-methylene-1-(1-methylethyl)- (7.32%), and α-terpinyl acetate (6.13%) as the major constituents. The antibacterial activity of the EO was evaluated against five bacterial strains using the microbroth dilution assay. It showed notable activity, particularly against Gram-positive bacteria, with a minimum inhibitory concentration (MIC) of 1% (v/v). The antibacterial mechanism of the essential oil against S. aureus was investigated by scanning electron microscopy (SEM), which revealed severe morphological alterations including membrane disruption, cell deformation, and cytoplasmic leakage. Moreover, molecular docking of the main compounds with the acylated penicillin-binding protein 2a from methicillin-resistant S. aureus (PDB: 1MWT) demonstrated promising interactions. These findings highlight the potential of Solenanthus tubiflorus Murb. EO as a natural antibacterial agent.

This study explores the production of gelatin hydrolysates with metal-chelating peptides derived from red tilapia scales and investigates their biofunctional properties. Gelatin was enzymatically hydrolyzed using Alcalase (Alc-GH), Flavourzyme (Flav-GH), or a sequential combination of Alcalase and Flavourzyme (Alc+Flav-GH). Alc-GH and Alc+Flav-GH were ultrafiltrated at 1 kDa cutoff. Alc+Flav-GH, characterized by a high proportion of small-sized peptides, exhibited superior metal-chelating ability, as determined by switchSENSE and was associated with enhanced antioxidant activity. Ultrafiltration improved the Fe2+-chelating properties of both fractions compared to their respective whole hydrolysates. All of the hydrolysates and their ultrafiltrates showed remarkable ACE inhibitory activity. Specifically, the <= 1 kDa Alc-GH fraction produced small-sized Fe2+-chelating peptides with ACE inhibitory activity, whereas the <= 1 kDa Alc+Flav-GH fraction efficiently generated Ni2+-chelating peptides with strong antioxidant potential. LC-MS/MS data showed peptides rich in Asp, Glu, Ser, Lys, and Arg, which may contribute to their metal-chelating and antioxidant properties.

Background: Antimicrobial resistance (AMR) represents a critical global health challenge, requiring innovative strategies to combat resistant bacterial strains. Cymbopogon essential oils (EOs) are promising natural antimicrobial agents. Methods: The EO of Cymbopogon commutatus was extracted by hydrodistillation from fresh aerial parts and compared to commercial EOs from C. citratus, C. nardus, and C. winterianus. Antibacterial activity was evaluated against seven bacterial strains (two Gram-positive and five Gram-negative). Both water-soluble fractions and liposome-encapsulated formulations were tested. Liposomes were prepared using soybean lecithin, and their stability was assessed by dynamic light scattering (DLS). The chemical composition of the pure EOs, water-soluble fractions and non-water-soluble fractions was analyzed by gas chromatography–mass spectrometry (GC-MS). Results: Liposome encapsulation improved EO solubility in aqueous media and significantly enhanced antibacterial efficacy, reducing minimum inhibitory concentration (MIC) values compared to the water-soluble fractions (MICs ≥ 25%). Among the tested formulations, the liposome containing C. citratus EO exhibited the strongest inhibitory effect against Staphylococcus aureus (MIC: 0.04%) followed by liposomes with C. nardus and C. commutatus (MIC: 0.08%). Against Enterococcus faecalis, the most effective formulation was the liposome containing C. winterianus EO (MIC: 0.02%), followed by C. citratus (MIC: 0.08%). The liposome formulated with C. winterianus maintained its particle size over 72 h without phase separation. GC-MS analysis revealed distinct phytochemical profiles: C. commutatus EO was rich in piperitone (73.9%) and C. citratus was rich in (Z)-(3,3-Dimethyl)-cyclohexylideneacetaldehyde (39.9%) and citral (32.5%), while C. nardus and C. winterianus were dominated by geraniol (21.5%) and citronellal (30.8%), respectively. Notably, piperitone, the major compound in C. commutatus EO, exhibited strong antibacterial activity against S. aureus (MIC of <0.04%). Conclusions: These findings support the potential of liposome-encapsulated Cymbopogon EOs as an effective and sustainable strategy to address AMR. This study provides a foundation for the development of plant-based antimicrobial formulations with improved efficacy.

We describe here the preparation of a new class of photosensitizers cyclophane represented by a family of asymmetrical N-bisheterocyclic bis-imidazolium bromide macrocycles. 1H NMR, 2D NMR, mass spectroscopy measurements, crystallographic x-ray structures and photophysical properties of these cyclophane imidazolium salts are described, as well as the evaluation of their anti-microbial activity.

The current study aimed to investigate the chemical composition, antioxidant, antibacterial, and cytotoxic properties of three extracts (hexane, dichloromethane, and methanol) from Cynoglossum tubiflorus. The composition of the methanolic extract was elucidated using HPLC-HESI-MS/MS analysis. The antioxidant effect was examined using NO, DPPH, FRAP, and TAC assays. Antimicrobial activity was evaluated by broth microdilution using various bacterial strains such as S. aureus, S. epidermidis, P. aeruginosa, E. coli, and K. pneumoniae. Structural disruptions in Gram-positive bacteria were visualized using scanning electron microscopy (SEM). Cytotoxic effects were evaluated on human MRC-5 in culture according to the MTT assay. The outcomes suggest that methanol extract contained a high amount of phenolic compounds (254.35 ± 0.360 mg GAE/g DE and 211.59 ± 0.939 mg QE/g DE). By applying the HPLC-HESI-MS/MS analysis, 32 compounds were identified, including phenolic acids, flavonoids, lignans, and fatty acids. This extract showed strong antioxidant (IC50 = 0.043 ± 0.001 mg/mL) and antimicrobial (MIC = 156 µg/mL) activities. The SEM suggests that cells exhibited membrane distortions characterized by surface depressions and alterations in bacterial shape, including dents, when compared to untreated cells. The in vitro cytotoxicity effect on human MRC-5 cells showed no toxicity effects at a concentration of 600 µg/mL. In silico analysis predicted low toxicity for all tested compounds across four different administration routes. This research indicates that this plant could be explored as a powerful source of natural drugs to target pathogens, with applications in the food, pharmaceutical, and medical industries.

A novel symmetric tetra-imidazolium-bis-heterocycle, called C7, was designed and synthesized in a quick two-step pathway, with the objective to synthesize biologically active supramolecular assembly. The synthesized compound was then analyzed for its photophysical properties, for a potential application in theragnostic (fluorescence) or phototherapy (photodynamic therapy, with the production of reactive oxygen species, such as singlet oxygen 1O2). C7 was thus screened for its biological activity, in particular against important human pathogens of viral origin (respiratory viruses such as adenovirus type 2 and human coronavirus 229E) and of fungal and bacterial origin. The compound showed limited antiviral activity, combined with very good antiproliferative activity against breast cancer, and head and neck squamous cell carcinoma models. Interestingly, the selected compound showed excellent antibacterial activity against a large array of Gram-positive and Gram-negative clinically isolated pathogenic bacteria, with a possible inhibitory mechanism on the bacterial cell wall synthesis studied with electron microscopy and molecular docking tools. Collectively, the newly synthesized compound C7 could be considered as a potential lead for the development of new antibacterial treatment, endowed with basic photophysical properties, opening the door towards the future development of phototherapy approaches.

Bazzania trilobata (L.) Gray is a leafy liverwort from the family of Lepidoziaceae, well known for its antifungal properties. In this study, the 70% ethanol and methanol extracts of B. trilobata were investigated for new in vitro biological activities of cosmetic interest. The results showed that the total phenol content, the DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity, and the anti-collagenase activity of the 70% ethanol extract were higher than for methanol. The methanol extract showed mild tyrosinase inhibitory activity and antimicrobial properties towards the Gram-positive bacteria Enterococcus faecalis. Lignans, coumarins, and bis-bibenzyls were the major classes of phenolic constituents tentatively identified in both extracts. In addition, a known drimenyl caffeate was identified in B. trilobata and its structure was confirmed by NMR spectroscopy. These results suggest that extracts from B. trilobata could be exploited as an interesting new source of natural active ingredients for cosmetic applications.

The Gram-positive bacterium Staphylococcus epidermidis is responsible for important nosocomial infections. With the continuous emergence of antibiotic-resistant strains, the search for new treatments has been amplified in the last decades. A potential candidate against multidrug-resistant bacteria is squalamine, a natural aminosterol discovered in dogfish sharks. Despite its broad-spectrum efficiency, little is known about squalamine mode of action. Here, we used atomic force microscopy (AFM) imaging to decipher the effect of squalamine on S. epidermidis morphology, revealing the peptidoglycan structure at the bacterial surface after the drug action. Single-molecule force spectroscopy with squalamine-decorated tips shows that squalamine binds to the cell surface via the spermidine motif, most likely through electrostatic interactions between the amine groups of the molecule and the negatively-charged bacterial cell wall. We demonstrated that - although spermidine is sufficient for the initial attachment of squalamine to S. epidermidis - the integrity of the molecule needs to be conserved for its antimicrobial action. A deeper analysis of the AFM force-distance signatures suggests the implication of the accumulation-associated protein (Aap), one of the main adhesins of S. epidermidis, in the initial binding of squalamine to the bacterial cell wall. This work highlights that AFM -combined with microbiological assays at the bacterial suspension scale- is a valuable approach to better understand the molecular mechanisms behind the efficiency of squalamine antibacterial activity.

Fusarium tricinctum is among the pathogenic fungi that contaminate cereal crops, including barley. It produces toxic metabolites such as enniatins (ENNs) that affect the quality and safety of barley-based products such as malt and beer, thus representing a significant concern for the cereal industries. Therefore, it is critical to reduce Fusarium spp. development and enniatin contamination in cereal-based products. Fungicides are commonly used during agricultural practices, but they are facing growing fungal resistance and environmental and health concerns. Hence, there is need to define environmentally friendly control strategies. This study highlights the ability of a bacterial strain isolated from barley kernels, namely Erwinia gerundensis 6E4, to inhibit the growth of Fusarium tricinctum and to reduce its toxigenic potential. First, E. gerundensis 6E4 exhibited a significant fungistatic activity against pathogenic fungal strains during co-cultures, with fungal growth reduced by up to 100% on Petri dishes and by about 69% in liquid medium. The bacterial strain also led to a drastic reduction (74 to 100%) of ENNs production by F. tricinctum strains over 72 h co-cultures. Based on these results, our study supports the use of E. gerundensis 6E4 as a biocontrol agent in strategies aiming at reducing the presence of Fusarium tricinctum and enniatins in cereal-based products, or as a food and feed supplement for the bio-detoxification of enniatins.

Phenolic compounds, naturally present in plants, are particularly relevant as nutraceutics for their antioxidant activities. Here, choline chloride-based natural deep eutectic solvents (NaDESs) were used for efficient extraction of total phenolic compounds (TPC) from leaves, pods and roots ofRhamn u s alaternus plant. In each extract, the polyphenols content and their antioxidant activities were evaluated. More, their antibacterial activity was car-ried out against Gram-positive and Gram-negative bacteria. The investigated extracts presented antioxidant and antimicrobial activities. The leaves, pods and roots extracts obtained using the choline chloride-glycerol (ChCl-Gly) mixture exhibited a high value of TPC comprised within 437.7 and 317.0 mg GAE/100 g d.w. and showed the best antioxidant properties with ABTS radical scavenging capacity (IC50: from 44.55 to 53.56 ,ig/mL), DPPH assay (IC50: from 26.36 to 118.23 ,ig/mL), reducing activity (EC50: from 77.53 to 85.05 ,ig/mL) and iron che-lation activity (EC50: from 91.73 to 108.7 ,ig/mL). In contrast, choline chloride-urea (ChCl-Ur) extracts showed a low antioxidant capacity. Lastly, the best bioactive extracts were characterized using HPLC-MS/MS to determine their bioactive compounds. The present study suggests that the DES-based method developed was selective, efficient and sustainable for extraction of polyphenols.

Ocimum plants are of great interest to traditional medicine in the history of several civilizations, particularly in terms of chronic human diseases. Essential oils obtained from this genus have also been used as therapeutic agents. In this present work, two plants of the Ocimum species from Djibouti, Ocimum basilicum L. and Ocimum americanum L., were subjected to hydrodistillation to obtain their essential oils. Gas chromatography-mass spectrometry was performed to determine the chemical composition of both essential oils. Linalool (41.2%) and estragole (30.1%) are the major compounds among the 37 compounds that have been identified in the essential oil of Ocimum basilicum L. (EOOB), and carvotanacetol (38.4%) and estragole (27.5%) are the main compounds among the 42 compounds that have been identified in the essential oil of Ocimum americanum L. (EOOA). Morever, the cytotoxic activity of EOs was evaluated against 13 human cancer cell lines (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC -5 and JIMT-T1) using a luminescence spectrophotometric method; hence, the oils showed significant cytotoxic activities. The antibacterial activities of the oils were assayed on five Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, Staphylococcus epidermidis and Corynebacterium sp.) and seven Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Shigella sonnei, Salmonella enterica sv. Typhimurium and Enterobacter cloacae) by agar disc diffusion methods. Both essential oils exhibited moderate activities against Streptococcus agalactiae, and thus each has an activity against Pseudomonas aeruginosa for EOOB and against Enterobacter cloacae for EOOA, while the others are negative. The findings of this work showed the promising anticancer effects of both oils against total cell lines with a potential for use as natural alternatives to synthetic drugs; however, there was only an antibacterial effect against Streptococcus agalactiae.

Ruta chalepensis L. (Rutaceae) is a tropical medicinal plant traditionally used in the Republic of Djibouti to treat several diseases, including tumors. In this study, the anticancer activities of this plant from Djibouti were investigated according to an in vitro evaluation method and statistical modeling. The results obtained will make it possible to complete the previous work already published on this genus of plant, in particular by using untested cancer cell lines, such as U87-MG, U2OS, RT4, PC3, NCI-N87, MRC-5, MIA-Paca2, K562, JIMT-T1, HEK293, HCT116, A549, and A2780. The main volatile compound turned out to be 2-undecanone (51.3%). Correlation modeling was performed from the principal component analysis (PCA) of IC50 of the essential oil and four active substances (vinblastine, doxorubicin, combrestatin A4, and monomethyl auristatin E) versus the cancer cell lines tested, which confirmed the effectiveness of the oil against 6 lines: U2OS, NCI-N87, MRC-5, MIA-Paca2, JIMT-T1, and HEK293. These data reveal promising prospects for good biomass management through the future exploitation of the R. chalepensis L. essential oil as a potential source of natural anticancer agents for targeted investigations.

The aim of this research was to evaluate the essential oils of two medicinal plants from Djibouti: Cymbopogon schoenanthus (L.) Spreng. and Nepeta azurea R.Br. ex Benth. in cytotoxic activity against thirteen (13) cancer cell lines (A2780, A549, HCT116, HEK-293, JIMT-T1, K562, MIA-Paca2, MRC5, NCI-N87, PC3, RT4, U2OS and U87-MG) and antibacterial activity against seven (7) Gram (−) strains (Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica sv. Typhimurium and Shigella sonnei) and five (5) Gram (+) strains (Corynebacterium sp., Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae). The plants were extracted by hydrodistillation and were analyzed by GC-MS. The main components of Cymbopogon schoenanthus essential oil (CSEO) were 3-isopropenyl-5-methyl-1-cyclohexene (32.3%) and D-Limonene (11.3%), and the main component of Nepeta azurea essential oil (NAEO) was methyl (2E)-2-nonenoate (53.2%). The two essential oils showed inhibitory cytotoxicity activities of all the cancer cells tested; on the other hand, the antibacterial activities are only well-noticed for the CSEO oil at a concentration of 5% against Klebsiella pneumoniae, Pseudomonas aeruginosa, Corynebacterium sp., Enterococcus faecalis and Staphylococcus aureus. Our results demonstrated that the two essential oils could be effective natural anticancer agents, in addition to an antibacterial character for Cymbopogon schoenanthus essential oil.

The chemical composition of the essential oils of two plants (Tagetes minuta L. and Lavandula coronopifolia L.) harvested from the Day region (in the north of Djibouti) is the subject of this study. The extraction of essential oils was carried out by hydrodistillation, and the average yield was obtained at a rate of approximately 0.25% for Tagetes minuta L. and 0.42% for Lavandula coronopifolia L. The analyses of these essential oils by gas chromatography coupled with mass spectrometry identified 13 compounds in the essential oil of Tagetes minuta L., including dihydrotagetone (20.8%), artemisia (17.9%), (Z)-tagetenone (12.4%), (-)-spathulenol (11.0%) and estragole (9.5%), were obtained as majority compounds, with a percentage of 71.6%. The essential oil of Lavandula coronopifolia L. is characterized by the presence of 42 compounds, including cis-caryophyllene (18.9%), dehydronerolidol (12.8%), isolongifolanone (11.2%), caryophyllene oxide (8.2%), 10-epi-β-eudesmol (7.7%) and humulene (5.1%), were obtained as the majority chemical constituents, with a percentage of 63.9%. The antimicrobial activities of the essential oils at concentrations of 5% were measured against 12 bacterial strains (Gram positive: Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Streptococcus agalactiae (ATCC 27956), Staphylococcus epidermidis and Corynebacterium sp.; Gram Negative: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), Acinetobacter baumannii (ATCC 19606), Shigella sonnei (ATCC 9290), Salmonella enterica sv. Typhimurium (ATCC 13311) and Enterobacter cloacae), and the results of in vitro experiments showed inhibitory effects against most strains tested except Staphylococcus aureus, Enterococcus faecalis and Streptococcus agalactiae. Additionally, both oils were tested for their ability to selectively kill 13 human cancer cells (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC-5 and JIMT-T1), and the results obtained, according to the values of IC50, show the significant activity of two essential oils, particularly on the HCT116 and A2780 lines, which present values between 0.25 µg/mL and 0.45 µg/mL, respectively.

Water extract of Acacia seyal bark is used traditionally by the population in Djibouti for its anti-infectious activity. The evaluation of in vitro antibacterial, antioxidant activities and cytotoxicity as well as chemical characterization of Acacia seyal bark water and methanolic extracts were presented. The water extract has a toxicity against the MRC-5 cells at 256 μg/mL while the methanolic extract has a weak toxicity at the same concentration. The methanolic extract has a strong antioxidant activity with half maximal inhibitory concentration (IC50) of 150 ± 2.2 μg/mL using 1-diphenyl-2-picrylhydrazyl (DPPH) and IC50 of 27 ± 1.3 μg/mL using 2,2′-azino-bis 3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical methods. For ferric reducing/antioxidant power (FRAP) assay, the result is 45.74 ± 5.96 μg Vitamin C Equivalent (VCE)/g of dry weight (DW). The precipitation of tannins from methanol crude extract decreases the MIC from 64 µg/mL to 32 µg/mL against Staphylococcus aureus and Corynebacterium urealyticum. However, the antioxidant activity is higher before tannins precipitation than after (IC50 = 150 µg/mL for methanolic crude extract and 250 µg/mL after tannins precipitation determined by DPPH method). By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, the results showed that the condensed tannins consist of two types of catechin and gallocatechin-based oligomers. The fractionation led to the identification of three pure compounds: two flavanols catechin and epicatechin; one triterpene as lupeol; and a mixture of three steroids and one fatty acid: campesterol, stigmasterol, clionasterol, and oleamide.

Phenolamides constitute a family of metabolites, widely represented in the plant kingdom, that can be found in all plant organs with a predominance in flowers and pollen grains. They represent a large and structurally diverse family, resulting from the association of phenolic acids with aliphatic or aromatic amines. Initially revealed as active compounds in several medicinal plant extracts, phenolamides have been extensively studied for their health-promoting and pharmacological properties. Indeed, phenolamides have been shown to exhibit antioxidant, anti-inflammatory, anti-cancer and antimicrobial properties, but also protective effects against metabolic syndrome and neurodegenerative diseases. The purpose of this review is to summarise this large body of literature, including in vitro and in vivo studies, by describing the diversity of their biological properties and our actual knowledge of the molecular mechanisms behind them. With regard to their considerable pharmacological interest, the question of industrial production is also tackled through chemical and biological syntheses in engineered microorganisms. The diversity of biological activities already described, together with the active discovery of the broad structural diversity of this metabolite family, make phenolamides a promising source of new active compounds on which future studies should be focused.

(1) Background: Viral respiratory infections cause life-threatening diseases in millions of people worldwide every year. Human coronavirus and several picornaviruses are responsible for worldwide epidemic outbreaks, thus representing a heavy burden to their hosts. In the absence of specific treatments for human viral infections, natural products offer an alternative in terms of innovative drug therapies. (2) Methods: We analyzed the antiviral properties of the leaves and stem bark of the mulberry tree (Morus spp.). We compared the antiviral activity of Morus spp. on enveloped and nonenveloped viral pathogens, such as human coronavirus (HCoV 229E) and different members of the Picornaviridae family—human poliovirus 1, human parechovirus 1 and 3, and human echovirus 11. The antiviral activity of 12 water and water–alcohol plant extracts of the leaves and stem bark of three different species of mulberry—Morus alba var. alba, Morus alba var. rosa, and Morus rubra—were evaluated. We also evaluated the antiviral activities of kuwanon G against HCoV-229E. (3) Results: Our results showed that several extracts reduced the viral titer and cytopathogenic effects (CPE). Leaves’ water-alcohol extracts exhibited maximum antiviral activity on human coronavirus, while stem bark and leaves’ water and water-alcohol extracts were the most effective on picornaviruses. (4) Conclusions: The analysis of the antiviral activities of Morus spp. offer promising applications in antiviral strategies.