In this work, heather and its flowers were studied regarding their antioxidant and antimicrobial activities. Plants were subjected to ultrasound‐assisted methanolic extraction followed by fractionation. A phytochemical characterisation of extracts content in total phenols and flavonoids, and their antioxidant activity was performed. The antimicrobial activity was evaluated through the determination of minimum inhibitory concentration and by bioautography. Following, studies on the antilisterial potential were carried out by: time‐kill curves, inhibition of biofilm formation and tolerance of Listeria monocytogenes to adverse conditions. The results evidenced the antioxidant activity in both extracts, as well as, the antimicrobial activity against Gram‐positive bacteria. Concerning the evaluation of the antilisterial potential, a bacteriostatic behaviour and inhibition of biofilms formation ability were observed. Listeria monocytogenes showed an increased susceptibility to adverse conditions when preincubated with extracts. Thus, heather and its flowers may be a source of new compounds with antilisterial activity potential.

Increasing resistance of pathogens towards conventional antibiotics presents a major threat to public health because it reduces the effectiveness of antibiotic treatment. Mentha pulegium L., also known as pennyroyal, is an aromatic herb that belongs to the family Lamiaceae. Its essential oil has been traditionally used in medicine, aromatherapy, and cosmetics. The purpose of this work was to study the chemical composition of a pennyroyal essential oil and to evaluate their bioactivities, specifically, antioxidant, antimicrobial, anti-quorum sensing, and anti-inflammatory. A special focus was given to the antibacterial activity of the essential oil against Acinetobacter baumannii. The chemical composition of the essential oil was studied by GC-MS/GC-FID. The DPPH free radical scavenging assay and the β-carotene/linoleic acid system were used to evaluate the antioxidant properties. The antimicrobial and anti-quorum sensing activities were evaluated by disk diffusion assays and complemented with optical microscopy observations. The results showed that pulegone was the major compound (88.64%) of the pennyroyal essential oil. Regarding the antimicrobial activity, the action against Acinetobacter baumannii stands out, which, together with the capacity of the essential oil to inhibit the quorum sensing mechanisms, may suggest the use of the pennyroyal essential oil to further develop surface disinfectants for hospitals.

The frequent isolation of Arcobacter butzleri and Arcobacter cryaerophilus from food samples makes it imperative to search for potential compounds able to inhibit the development of these bacteria. Taking this into consideration, this study focuses on the antimicrobial activity of resveratrol and its mechanism of action against A. butzleri and A. cryaerophilus. The activity of resveratrol was assessed by a microdilution method and time-kill curves. Resveratrol effect on cellular functions was assessed by flow cytometry evaluating intracellular DNA content and metabolic activity. Ethidium bromide (EtBr) accumulation in the presence of resveratrol was also evaluated, as well as the susceptibility to resveratrol in the presence of phenylalanine-arginine β-naphthylamide (PAβN). Scanning electron microscopy (SEM) was used to further evaluate cell damage caused by resveratrol. Resveratrol presented MIC values of 100 and 50μg/mL to A. butzleri and A. cryaerophilus, respectively. Based on the time-kill curves, resveratrol exhibited bactericidal activity, leading to a ≥3log10CFU/mL reduction of initial inoculums, for A. butzleri exponential phase cells incubated for 6h with 1× MIC or with 2× MIC after 24h for stationary phase cells. For A. cryaerophilus cells in exponential growth phase, 99.9% killing was achieved after 24h incubation with 2× MIC, whereas, for stationary phase cells, bactericidal activity was only detected after incubation with 4× MIC. Incubation with resveratrol led to a decrease in both intracellular DNA content and metabolic activity. An increase in the accumulation of EtBr was observed in the presence of resveratrol, and the efflux pump inhibitor PAβN reduced the MIC of resveratrol. SEM analysis revealed disintegration of A. butzleri cells treated with resveratrol, whereas no morphological alteration was observed for A. cryaerophilus cells. Resveratrol has a good anti-Arcobacter activity, and the results obtained suggest that this compound could act through several different mechanisms in the inhibition of this microorganism. The results encourage the use of this compound for the development of potential strategies to control Arcobacter in food products.

Healing enhancement and pain control are critical issues on wound management. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan (deacetylation degree 95%) and agarose. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The performance of the hydrogel in the wound healing process was evaluated through in vivo assays, during 21 days. The attained results revealed that hydrogel has a pore size (90–400 μm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 μg/mL of chitosan. The improved healing and the lack of a reactive or a granulomatous inflammatory reaction in skin lesions treated with hydrogel demonstrate its suitability to be used in a near future as a wound dressing.

The common therapeutic indications of Portuguese Natural Mineral Waters (NMWs) are primarily for respiratory, rheumatic and muscu- loskeletal systems. However, these NMWs have been increasingly sought for dermatologic purposes. Opposing to what is observed in the major European Thermal Centres, there are few scientific evidences supporting the use of Portuguese NMWs for clinical applications. The aim of this study was to characterize the antimicrobial profile of individual NMWs from the central region of Portugal and correlate the results with their physicochemical characterization. An extensive multivariate analysis (principal component analysis) was also performed to further investigate this possible correlation. Six collection strains representing skin microbiota, namely Staphylococcus aureus, Escher- ichia coli, Corynebacterium amycolatum, Candida albicans, Staphylococcus epidermidis and Cutibac- terium acnes, were analysed, and their antimicrobial profile was determined using Clinical and Laboratory Standards Institute M07-A10, M45-A2, M11-A6 and M27-A3 microdilution methods. Different NMWs presented different antimicrobial profiles against the strains used; the physicochemical composition of NMWs seemed to be correlated with the different susceptibility profiles. Cutibacterium acnes showed a particularly high susceptibility to all NMWs belong- ing sulphurous/bicarbonated/sodic ionic profile, exhibiting microbial reductions up to 65%. However, due to the complex physicochemical composition of each water an overall conclusion regarding the effect of a specific ion on the growth of different microor- ganisms is yet to be known.

Medicinal plants have long been regarded as essential therapeutic resources in traditional and complementary medicine. In recent decades, they have attracted increasing scientific interest due to their bioactive compounds and pharmaceutical potential. Iran, with its diverse climate and abundant flora, provides unique opportunities for ethnobotanical and pharmacological research, as traditional knowledge of medicinal plants remains deeply embedded in local healthcare practices. Ethnobotanical surveys conducted in the provinces of Guilan, Alborz, and Qazvin revealed that plant species belonging to the Asteraceae, Lamiaceae, and Boraginaceae families are the most frequently cited in traditional medicine. These findings highlight both the cultural and therapeutic significance of these families, as well as their potential for guiding pharmacological research. Among the documented species, Tripleurospermum disciforme (C.A. Mey.) Sch. Bip. and Echium amoenum Fisch. & C.A. Mey. were among the most frequently cited medicinal plants. T. disciforme recorded the highest Relative Frequency of Citation (RFC = 0.42) and Use Value (UV = 1.72), indicating widespread reliance and strong consensus regarding its therapeutic effectiveness, particularly in treating digestive, respiratory, skin, and nervous system disorders. These ethnobotanical indicators justified its selection for further scientific investigation in this thesis. In contrast, although Echium amoenum presented a slightly lower frequency (RFC = 0.32, UV = 1.31), it remains one of the most culturally and therapeutically relevant species of the Boraginaceae family, known in Iranian folk medicine for its role in digestive, neurological, inflammatory, and infectious conditions. Considering that other highly cited genera, such as Thymus kotschyanus and Mentha spp. (Mentha pulegium L., Mentha arvensis L., Mentha aquatica L., Mentha piperita L.) have been extensively studied in recent years, Echium spp., was selected for a systematic review, focusing on its phytochemical, ethnomedicinal, and pharmacological properties. Although biological analyses could not be completed within the present timeframe, they are planned for future work to further explore its therapeutic potential. A systematic review of the genus Tripleurospermum was conducted to contextualize its phytochemical diversity and pharmacological properties. Compounds such as terpenes, flavonoids, tannins, phenolic compounds, and essential oils were reported to contribute to antioxidant, antimicrobial, anti-inflammatory, and sedative activities. Experimental analyses of T. disciforme confirmed the presence of phenolic compounds neochlorogenic acid, caffeic acid, and p-hydroxyphenylethyl acetate identified using UHPLC–timsTOF–MS. The ethyl acetate extract fraction exhibited the strongest antioxidant capacity in DPPH radical scavenging (IC₅₀ = 12.49 μg/mL) and significant antimicrobial activity against Bacillus cereus (MIC = 312 μg/mL). Regarding cytotoxicity, the hexane extract fraction displayed marked cytotoxic effects against the human breast adenocarcinoma (MCF-7) cell line, while showing lower toxicity toward normal fibroblast cells, supporting its selective anticancer potential. The systematic review of the genus Echium L., based on the ethnobotanical relevance identified in the field study, compiled data on its phytochemical composition including phenolic compounds, naphthoquinones, shikonins, sterols, fatty acids, and pyrrolizidine alkaloids and summarized its reported antioxidant, antimicrobial, and cytotoxic activities. However, the presence of toxic alkaloids underlines the necessity for further preclinical and clinical investigations before therapeutic application. By integrating ethnobotanical, phytochemical, and pharmacological approaches, this thesis provides a comprehensive overview of the therapeutic potential of Tripleurospermum disciforme and Echium species. The results reaffirm their importance in Iranian traditional medicine and highlight their promise as valuable candidates for the development of new plant-based therapeutic agents.

The synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The alpha-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding beta-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl) methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside alpha-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups

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Bacterial multidrug resistance is to global public health a serious problem. With the emergence of multidrug-resistant bacteria pharmaceutical industry focuses on developing new drugs that are effective in antimicrobial therapy, which presents low cost, high efficiency and has reduced side effects. That is why new research and investments are needed. Several studies have shown that the Schiff Bases are potential compounds with pharmacological effect, some examples of these compounds being semicarbazide, thiosemicarbazides and hydrazines. Condensation reactions of these compounds with aldehyde or ketone, and metals allow the generation of new structural modifications that can produce relevant biological effects against fungi and pathogenic bacteria. The objective of this work was to evaluate the biological potential of organic binders based on thiosemicarbazones, semicarbazones, hydrazones and their metal complexes on fungi and bacteria. Organic binders of the class of the semicarbazones, thiosemicarbazones and hydrazones were obtained by a condensation reaction of a semicarbazide, thiosemicarbazide or hydrazine with an aldehyde or ketone and sequentially with a transition metal. Three binders and two metal complexes were obtained: NMHC, NMHC+ Sn, MTHC, NMH, NMH+Sn. The biological activity was verified by means of microbiological tests to evaluate the antifungal and antibacterial activity of each compound, using the technique of microdilution in a 96-well flat bottom plate. The evaluation of the antimicrobial activity was performed with ten microorganisms and with the five potential drugs. Three novel compounds showed antimicrobial activity. The binders NMH (hydrazone) and MTHC (semicarbazone) showed no antimicrobial activity at the concentrations tested (1024 mgL-1 to 0.5 mgL-1) on the ten tested microorganisms. The binder NMHC (thiosemicarbazone) only showed activity against Candida albicans strain tested at a concentration of 64 mgL-1. The metal complexes presented antibacterial activity against seven strains and antifungal activity against the strains of Candida albicans and Candida parapsilosis. MICs of the NMHC + Sn and NMH + Sn complex ranged from 16 mgL-1 to 32 mgL-1. With these promising results we will continue the studies on the biological effects of these molecules unpublished in the scientific literature.

The purpose of this work is to carry out the phytochemical study and evaluate biological activities of the essential oil and extracts of the Pimenta pseudocaryophyllus (Gomes) L.R. Landrum (Myrtaceae) leaves. Chapter 1 provides a review of the main botanical aspects of the genus Pimenta, its chemical composition and pharmacological potential. Chapter 2 describes the occurrence of infraspecific variability in P. pseudocaryophyllus. For this the essential oils from 12 specimens of P. pseudocaryophyllus that occur naturally in three different locations of the Brazilian Cerrado underwent a qualitative and quantitative analysis by gas chromatography-mass spectrometry (GC/MS). The multivariate statistical analysis identified three chemotypes of P. pseudocaryophyllus, characterized by the predominance of citral, (E)-caryophyllene and (E)-methyl isoeugenol constituents. Chapter 3 presents the phytochemical assessment of the hexane, dichloromethane, ethyl acetate and aqueous fractions obtained from the crude ethanol extract of P. pseudocaryophyllus leaves. Chromatographic and spectrophotometric (1H and 13C) methods enabled the isolation and identification of lupeol, α-and -amyrin, oleanolic, ursolic and betulinic acids, quercetin, quercitrin, isoquercitrin, afzelin, avicularin, guaijaverin, catechin, ellagic acid and gallic acid. Chapter 4 assesses the antimicrobial activity of the ethanol extracts, fractions (hexane, dichloromethane, ethyl acetate and aqueous), essential oils and isolated compounds of citral (CQ) and (E)-methyl isoeugenol (MQ) chemotypes of P. pseudocaryophyllus. The broth microdilution test was applied to determine the minimum inhibitory concentration (MIC) against strains of Gram(+) and Gram(-) bacteria, and of Candida and Cryptococcus spp fungi. The CQ and MQ dichloromethane fraction, CQ ethyl acetate fraction, and CQ essential oil were the most active (MIC = 62.5 to 500 mg / mL) against Gram(+). The oleanolic acid proved to also be responsible for this action. The CQ and MQ extracts of P. pseudocaryophyllus were active (MIC = 7.8 to 500 mg / mL) against most strains of Candida spp and Cryptococcus spp, where gallic acid, ellagic acid and quercitrin contributed to this action. The data obtained indicate the antimicrobial potential of CQ and MQ P. pseudocaryophyllus against some infectious diseases. Chapter 5 describes the antinociceptive activity, in mice, of CQ and MQ ethanol extracts, CQ fractions and CQ essential oil, and the anti-inflammatory activity of CQ crude ethanol extract of P. pseudocaryophyllus. The abdominal writhing test induced by intraperitoneal administration (ip) of acetic acid (1.2% v / v) and the ear edema test induced by croton oil (2.5% V/V) were performed. The CQ crude ethanol extract (2000, 1000 and 500 mg/kg, po) showed a dose-dependent antinociceptive effect. Among the fractions, only the aqueous fraction was not active. The CQ essential oil (60, 200 and 600 mg / kg, po) presented significant antinociceptive activity, probably because of its high citral concentration. Pretreatment with CQ crude ethanol extract (2000, 1000 and 500 mg / kg) reduced edema by 14.3 ± 0.4 mg (control) to 10.9 ± 0.5, 11.3 ± 0, 4, 10.5 ± 0.5 mg, respectively. The analgesic effect may be related to an anti-inflammatory action observed in the ear edema test.