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This work aimed to develop and characterize liposomes and evaluate their antimicrobial carrier activity. In the preparation of liposomes, dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylserine (DPPS) and cholesterol (COL) in a proportion of 5: 3: 1 were used. Vesicle diameter, Polydispersion Index and Zeta Potential analyzes were performed. Atomic Force Microscopy (MFA) and Scanning Electron Microscopy (SEM) were used to determine the shape and morphology of the liposome surface. Microbiological assays were performed against standard and multiresistant bacteria Staphylococcus aureus and Escherichia coli. For the liposome modulating effect test without incorporation with norfloxacin and gentamicin reference antibiotics, the fraction was used at a subinhibitory concentration (MIC/8) and the drugs were microdiluted. The work follows a prospective approach to develop a possible liposomal source with antimicrobial reader properties.

Efflux pumps and β-lactamases are mechanisms of bacterial resistance that exist in Staphylococcus aureus, where both mechanisms are expressed simultaneously in the SA K4100 strain, with its efflux pump being characterized as QacC (Quaternary Ammonium Compounds C). The search for inhibitors of these mechanisms has grown gradually, with research on isolated compounds, including terpenes, which have innumerable biological activities, being common. This study sought to evaluate the antibacterial activity of Terpinolene against the S. aureus K4100 strain, carrying a QacC efflux pump and β-lactamase, as well as to evaluate its toxicity in the Drosophila melanogaster arthropod model. Determination of the Minimum Inhibitory Concentration (MIC) was performed by broth microdilution. Efflux pump inhibition was evaluated by the MIC reduction of Oxacillin and Ethidium Bromide (EtBr). β-Lactamase inhibition was analyzed by the MIC reduction of Ampicillin with Sulbactam. Toxicity was verified by mortality parameters and locomotor assays in D. melanogaster. The results demonstrated that Terpinolene did not present a direct antibacterial activity (MIC ≥ 1024 μg/mL). However, a reduction in MIC was observed when Terpinolene was associated with Oxacillin (161.26–71.83 μg/mL) and EtBr (45.25–32 μg/mL), possibly by a β-lactamase and efflux pump inhibition, thus evidencing a modulatory activity. Terpinolene presented D. melanogaster mortality with an EC50 of 34.6 μL/L within 12 h of exposure. Additionally, Terpinolene presented damage to the locomotor system after the second hour of exposure, with the effect increasing in a concentration-dependent manner. In conclusion, new tests should be carried out to investigate the Terpinolene reinforcement of antibiotic activity and toxic activity mechanisms of action.

Curcumin, along with its derivatives, form a large class of natural and synthetic compounds with notable biological activity. However, their highly reactive β-diketone moiety renders this type of compounds unstable at pH above 6.5. The substitution of this group for a mono-carbonyl solves this problem, while improving antibacterial and anti-inflammatory activities. A thiophene curcuminoid, (1E,4E)-1,5-Di(thiophen-2-yl)penta-1,4-dien-3-one (DB Thiophene), has been synthesised and its molecular and spectroscopic characterization is reported, as well as a complete vibrational assignment. An efflux pump inhibition assay determined that DB Thiophene exhibits a remarkable NorA and MepA efflux pump inhibition activity. Molecular docking studies were carried out in order to understand this inhibition mechanism.

In the present study, the chalcone (2E)-1-(3′-methoxy-4′-hydroxyphenyl)-3-(3-nitrophenyl)prop-2-en-1-one (C16H13NO5, hereafter named AVMNB) was synthesized and structurally characterized using the 1H and 13C NMR technique and GC-MS. The vibrational and electrochemical properties of the AVMNB chalcone and its antibacterial activity against multi-resistant strains of Escherichia coli 06 and Staphylococcus aureus 10 were evaluated. The FT-Raman, ATR-FTIR, and UV-VIS spectra of the polycrystalline samples were recorded at room temperature. Quantum chemistry theoretical calculations were used to obtain information about the normal vibration modes, and the electronic transitions and the quantum chemical parameters expected for this chalcone. The pharmacokinetics properties were also estimated using the SwissADME platform. The AVMNB chalcone displayed antibacterial activity against multi-resistant strains of Staphylococcus aureus 10 and Escherichia coli 06 when associated with the ciprofloxacin and gentamicin antibiotics, respectively, indicating that this compound may contribute to the control of antibacterial resistance.

Toxic metals can cause toxicity problems in the organisms exposed to them. Many substances are able to reverse this toxicity. Among the secondary metabolites of plant origin investigated are flavonoids. To evaluate the cytoprotective activity, dry mass and possible damage to the membranes of Lactuca sativa (lettuce) seedlings subjected to different concentrations of mercury chloride in association with rutin in suballelopathic concentration (8 μg/mL) were determined. It was observed that rutin gives cytoprotection to lettuce seedlings, allowing greater growth and development of the roots of these seedlings, probably through the coordination of mercury with the rutin molecule. The interaction of rutin with mercury chloride was evidenced through vibrational spectroscopy (Raman and FTIR). Although mercury chloride causes cytotoxicity in several plant species, its complex with rutin can mitigate these effects.

The family Piperaceae is known for presenting in its species flavoring, healing and antimicrobial properties among others. The objective of the present study was: to study the chemical profile of the essential oil of Piper rivinoides (EOPR); to analyze its anti-bacterial and antifungal potential, as well as to evaluate the antifungal and antibiotic-modifying capacity. The chemical constituents were identified by gas chromatography with flame ionization detector (GC-FID), allowing the identification of 7 constituents of a total of 86.99%. E-Isoelemicin was identified as the main constituent of petroleum (40.81%). Clinically relevant MIC results were obtained against fungi in which the inhibitory concentration remained

Essential oils are broadly used in the food, perfume, and pharmaceutical industries. These are associated with ecological functions of defense and attraction of pollinators, and usually undergo quantitative and qualitative variation in response to the environment. Thus, the aim of this chapter is to highlight the essential oil content, chemical composition, and biological activities of Baccharis milleflora.

The genus Baccharis (Asteraceae) demonstrated the presence of compounds with antibacterial, antifungal and antioxidant activities. Because of the increasing rates of antimicrobial resistance, adequate treatment of infections caused by Gram-negative bacteria has become challenging. The objective of the present study was evaluate the antibacterial and antibiotic-modifying activity of the essential oil obtained from Baccharis reticulata (Ruiz & Pav.) Pers. and the compound α-pinene against Pseudomonas aeruginosa and other multiresistant bacteria. An analysis by gas chromatography associated with mass spectrometry (GC/MS) revealed the presence of dilapiol (33.8 %), α-pinene (31.7 %) and β-pinene (9.4 %) as major components of the oil. The determination of the Minimum Inhibitory Concentration (MIC) revealed that the oil has antibacterial activity against S. aureus only. However, the oil potentiated the norfloxacin and gentamicin against all strains evaluated. Also, α-pinene increased the activity of norfloxacin against E. coli, as well as potentiated the activity of norfloxacin and gentamicin against S. aureus. Therefore, the authors conclude that the essential oil of B. reticulata, as well as the compound α-pinene, have antibacterial and antibiotic-modulating activities that make them useful in the development of new weapons against bacterial resistance.

The objective of this work was to evaluate the antioxidant, metal chelating and cytoprotective activity of the Eugenia jambolana Lam. extract, as well as of its flavonoid and tannic fractions, against the action of Mercury Chloride (HgCl2). Flavonoids were quantified and an LC-MS chromatographic analysis was performed to identify secondary metabolites. Fe2+ and Fe3+ chelation tests and antioxidant activity were carried out using the FRAP method. Microbiological tests were performed by microdilution to determine the Minimum Inhibitory Concentration (MIC). From these results the Minimum Bactericidal (MBC) and Minimum Fungicide Concentration (MFC) were evaluated. The allelopathy and cytoprotection assays were performed using eukaryotic and prokaryotic models. The results revealed the presence of phenolic acids and flavonoids in the E. jambolana extract and fractions. The sub-allelopathic concentration (64 μg/mL) was used and the results demonstrated the E. jambolana potential cytoprotective effect against mercury chloride.

Psidium guajava L. is a plant widely used for food and in folk medicine all over the world. Studies have shown that guava leaves have antifungal properties. In this study, Flavonoid and Tannic fractions were tested to investigate their chemical composition and antifungal potential in vitro.21 compounds in the two fractions, presenting a higher content of phenolic compounds. The antifungal assays were performed against Candida albicans, Candida tropicalis and Candida krusei by microdilution to determine the IC50 and the cell viability curve. Minimal Fungicidal Concentration(MFC) and the inhibitory effects of the association of the fractions with Fluconazole, as well as the assays used to verify any morphological changes were performed in microculture chambers based on the concentrations from the microdilution. The IC50 of the isolated fractions and the fractions associated with each other were calculated, varying from 69.29 to 3444.62 μg/mL and the fractions associated with fluconazole varied from 925.56 to 1.57 μg/mL, it was clear that the association of the natural product with the antifungal presented a synergism. The fractions affected pleomorphism capacity and have a potential antifungal activity as they caused fungal inhibition in isolated use, potentiated the action of Fluconazole, reducing its concentration and impeding morphological transition, one of the virulence factors of the genus.

The antimicrobial activity of psychotropic drugs, especially those of the class of mainly phenothiazines has been previously reported. Other drugs, including verapamil and trifluoperazine demonstrated to be effective against multidrug-resistant strains. Selective serotonin reuptake inhibitors (SSRIs) are antidepressant drugs that have presented significant activity against resistant bacterial resistance, but the antibacterial effect as well the antibiotic modulating properties of fluoxetine remain to be elucidated. Therefore, the present study aimed to evaluate in vitro, the antibacterial effect and the antibiotic modulating activity of fluoxetine against standard and multiresistant bacterial strains. The microorganisms used were Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. For the antibacterial tests, 10 mg fluoxetine hydrochloride were and diluted in 1 mL of dimethyl sulfoxide (DMSO) and then diluted in sterile distilled water to a concentration of 1024 μg/mL. To determine the Minimum Inhibitory Concentrations (MICs), the drugs were diluted to concentrations ranging from 512 to 0.5 μg/mL in 96-well microdilution plates. The evaluation of the modulatory activity of fluoxetine was performed by combining this drug with the following antibiotics: Erythromycin, Gentamicin, Imipenem, Norfloxacin and Tetracycline at subinhibitory concentrations (MIC/8). Our results demonstrated that the MIC fluoxetine were 256 and 102 μg/mL against standard and resistant strains of S. aureus, respectively. The MIC of fluoxetine against both standard and resistant strains of P. aeruginosa was 161 μg/mL and against E. coli, the MIC of fluoxetine was 102 μg/mL for both standard and resistant strains, demonstrating that this drug present significant antibacterial activity. The association of fluoxetine with gentamicin and erythromycin P. aeruginosa and E. coli presented synergistic effects, demonstrating that this drug can selectively modulate the activity of antibiotics of clinical use. In conclusion, fluoxetine presented significant antibacterial effect and potential antibiotic modulating activity against multiresistant bacteria. Therefore, additional studies are needed to characterize the antimicrobial properties of this drug, as well as the clinical implications of its use in the treatment of infections by resistant microorganisms.

The development of fungal resistance to antifungal drugs has been worsening over the years and as a result research on new antifungal agents derived from plants has intensified. Eugenia uniflora L. (pitanga) has been studied for its various biological actions. In this study the chemical composition and antifungal effects of the E. uniflora essential oil (EULEO) were investigated against Candida albicans (CA), Candida krusei (CK) and Candida tropicalis (CT) standard strains. The essential oil obtained through hydro-distillation was analyzed by gas chromatography coupled to mass spectrometry (GC-MS). To determine the IC50 of the oil, the cellular viability curve and the inhibitory effects were measured by means of the oil’s association with Fluconazole in a broth microdilution assay with spectrophotometric readings. The Minimum Fungicidal Concentration (MFC) was determined by solid medium subculture with the aid of a guide plate while the assays used to verify morphological changes emerging from the action of the fractions were performed in microculture chambers at concentrations based on the microdilution. Two major oil constituents stand out from the chemical analysis: selina-1,3,7(11)-trien-8-one (36.37%) and selina-1,3,7(11)-trien-8-one epoxide (27.32%). The concentration that reduced microorganismal growth was ≥8,192 μg/mL while the IC50 varied, this being between 1892.47 and 12491.80 μg/mL (oil), 10.07 – 80.78 μg/mL (fluconazole) and 18.53 – 295.60 μg/mL (fluconazole + oil). The combined activity (fluconazole + oil) resulted in indifference and antagonism. A MFC of the oil in association with fluconazole was recorded at the concentration of 8,192 μg/mL against CA and CK. The oil caused the inhibition of CA and CT morphological transition. In view of the results obtained, additional research is needed to elucidate the activity of the E. uniflora oil over genetic and biochemical processes regarding its effect on Candida spp. virulence.

Matricaria is a widespread genus of flowering plants of the family Asteraceae that grow in temperate regions of Europe, Asia, America and Africa. Some of the species are also naturalized in Australia. Some species of this genus such as Chamomiles are recognized medicinal plants and cultivated in several countries for commercial purposes: to obtain its blue essence, as herbal tea, and for pharmaceutical or cosmeceutical uses. The phytochemical composition of Matricaria spp. includes volatile terpenoids (e.g., α-bisabolol, bisabolol oxide A and B, β-trans-farnesene and chamazulene), sesquiterpene lactones such as matricin, and phenolic compounds (flavonoids, coumarins and phenolic acids). Their essential oil is obtained from the fresh or dried inflorescences by steam distillation, and additionally cohobation of the remaining water. The volatile composition of the essential oil, especially the content of the valuable components α-bisabolol and chamazulene, depends on the plant part, origin and quality of the source, genetic, and environmental factors. Moreover, other parameters, such as season of harvest and methods of extraction, can affect the extraction yield of the essential oils/extracts, their composition and, therefore, their bioactivity. Due to the importance of this genus and particularly M. recutita (M. chamomilla), this review focus on its cultivation, factor affecting essential oils’ composition and their role in traditional medicine, as antibacterial agents and finally as food preservatives.

The present study was aimed to validate the phenolic, flavonoids, alkaloids and tannins profile of Aspleniuma ethiopicum (Burm. f.) Becherer methanolic extracts using HPTLC (High-performance thin-layer chromatography). The chromatographic separation was performed using the standard method. The separation methodology was optimized and phytoconstituents of A. aethiopicum methanolic extracts were separated. The methanolic extract of A. aethiopicum showed several bands identified as known phenolic compounds. The obtained flavonoids profiles were identified. HPTLC alkaloids profile of A. aethiopicum revealed 11 types of alkaloids. The tannin profile of methanolic extracts of A. aethiopicum demonstrated 11 different types of tannins. The observed profiles will be used as phytomarker to identify the chemical constituents of A. aethiopicum methanolic extracts. These profiles will act as a fingerprint of A. aethiopicum and help us to distinguish from its adulterants. The observed profile will help us to identify the crude drugs and improve the therapeutic potentials of A. aethiopicum.

In this study, the Piper cernuum Essential Oil (EOPC) was tested against bacterial and fungal strains using the microdilution method to evaluate its minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), as well as its antibiotic modifying effect, in addition to observing the oils ability to cause fungal dimorphism and to generate an IC50 cell viability curve. The EO was obtained through hydrodistillation using a Clevenger-type apparatus with the dry leaves and analyzed by GC-FID, allowing the identification of 14 compounds, with the main compound being 4-epi-cis-dihydromarofuran (28.97%). An EOPC intrinsic activity was identified only against Candida albicans 4127 (IC50 56.851 μg/mL). Given the MIC results from the EOPC intrinsic activity against Staphylococcus aureus 10 at the concentration of 406 μg/mL, its association with fluconazole potentiated it’s antifungal action. The action of gentamicin was potentiated by the addition of the EOPC to Staphylococcus aureus 10 and Escherichia coli 06 strains, both with MIC

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