BackgroundPlant-derived polyphenols, including catechins, have been extensively studied for their anticancer properties for years. However, complex plant extracts may exhibit enhanced activity compared to isolated compounds owing to synergistic/additive phytochemical interactions. To date, the anticancer potential of extracts from in vitro-grown roots of Reynoutria japonica Houtt., a plant rich in catechins, has not been investigated.PurposeThis study aimed to evaluate the anticancer activity of R. japonica root extract obtained from in vitro culture and to compare its effects with isolated catechins, with particular emphasis on the extract’s potent synergistic/additive effects.MethodsMethanolic root extracts and pure catechins were tested against five human cancer cell lines (A549, MDA-MB-231, Ramos, Namalwa, Raji) and human fibroblasts (BJ) as a control using the MTT assay. The mode of cell death was assessed by flow cytometry and Annexin V-FITC/PI staining. In vivo toxicity of the extract and pure compounds was evaluated in the insect model Galleria mellonella.ResultsThe root extract induced a reduction in cancer cell viability comparable to that observed for isolated catechins, despite containing substantially lower concentrations of these compounds. This effect was most pronounced in lymphoma cells, which showed the highest sensitivity to extract treatment. Flow cytometric analysis indicated that the extract predominantly triggered apoptotic cell death.ConclusionDespite its low catechin concentration, the extract from roots of R. japonica Houtt. Exhibits biological activity comparable to that of higher concentrations of pure catechins, suggesting possible synergistic or additive interactions within the phytochemical matrix. Furthermore, toxicological evaluation in the insect model revealed no adverse effects of the extract at biologically active doses.

Callitriche cophocarpa Sendtn. (water starwort; Plantaginaceae) is an aquatic higher plant common in natural environments worldwide. The plant is used in folk medicine due to its ability to synthesize large amounts of secondary metabolites with a broad range of biological activity. This study used various types of tissue culture to produce safe plant material for medical purposes. The plants were subjected to elicitation through nitrogen deficiency, and their extracts were examined for biological activity. Qualitative phytochemical analysis of shoots in vitro showed the presence of phenolic acids and phenylethanoid and iridoid glycosides. Based on the results, cultures (stationary and agitated) grown in liquid medium were selected due to their greater effectiveness, i.e., plant growth and higher production of secondary metabolites, compared to a temporary immersion bioreactor. In the second part of the research, tissue cultures (stationary and agitated) were subjected to elicitation, where the stressor was a decreased level (¼N) or lack (0 N) of available nitrogen in the form of nitrate and ammonium ions. Compared to unelicited tissues, a greater accumulation of phenolic acids and phenylethanoid and iridoid glycosides was observed. However, when individual secondary metabolites within these classes were considered, some compounds showed reduced accumulation under elicitation with a medium containing a reduced concentration of N ions, which also resulted in decreased fresh weight growth. The antioxidant and antibacterial properties of extracts from both control and elicited plants were evaluated. The induction of synthesis of the phenolic acids and phenylethanoid and iridoid glycosides resulted in an increased reducing capacity and antibacterial properties against reference, antibiotic-resistant, and antibiotic-sensitive strains of Staphylococcus aureus. Callitriche cophocarpa grown in vitro is a rich source of valuable secondary metabolites. Elicitation by nitrogen deficiency activates biochemical pathways connected with phenolic compounds and phenylethanoid glycosides. The strong bactericidal properties of C. cophocarpa relate to a high level of accumulation of verbascoside and phenolic acids

Plant-pathogenic bacteria pose a serious threat to crop production, and although several methods have been established, preventive strategies remain the most widely applied. In this study we propose the controlled application of silver nanoparticles (AgNPs), synthesised using plant extracts from Artemisia absinthium, Artemisia vulgaris, Echium vulgare, Glechoma hederacea, Solidago canadensis and Urtica dioica, against economically important plant-pathogenic bacteria: Clavibacter sepedonicus and Ralstonia solanacearum (both quarantine pests), Erwinia amylovora and Xanthomonas campestris (regulated non-quarantine pests) as well as Dickeya solani and Pectobacterium carotovorum. The minimum bactericidal concentrations (MBC) of the AgNPs obtained from A. absinthium, A. vulgaris or S. canadensis, with values of 1.3-9.7 mg/L Ag, pointed to their high antibacterial activities. In contrast, application of the AgNPs synthesised with the extracts of E. vulgare, G. hederacea or U. dioica resulted in MBC ranging from 2 to 20 mg/L Ag. The potential phytotoxic effects of AgNPs on seeds and seedlings of Pisum sativum, Triticum aestivum, Solanum lycopersicum, Solanum melongena, Beta vulgaris and Phaseolus vulgaris during the first week of growth were also evaluated. No statistically significant phytotoxic impact on germination or early growth of the tested plants was observed after the application of AgNPs at the concentration of 40 mg/L Ag. The newly synthesised plant-derived AgNPs described here may contribute to the development of an ecofriendly strategy against plant-pathogenic bacteria and offer an alternative to pesticides in seed treatment and integrated disease management.

Reynoutria japonica Houtt. is the source of various phenolic compounds: phenolic acids, flawan-3-ols, and stilbenes, with a broad range of biological activity. The rhizome (underground organ of these plants) is abundant in secondary metabolites but, in natural conditions, may accumulate various toxic substances (such as heavy metals) from the soil. The principal objective of this research was to produce transformed cultures of R. japonica hairy roots that would serve as a valuable source of phenolic compounds, independent of environmental resources. The transformation was performed using a variety of wild strains of Rhizobium rhizogenes bacteria, of which only strain A4 (ATCC 31798) proved effective. The molecular characterization of transformed clones was performed using PCR. The biometric parameters (growth index and dry weight content), phenolic compounds accumulation (DAD-HPLC), antioxidant capacity (DPPH, CUPRAC), and bactericidal properties against Staphylococcus aureus with various sensitivity to antibiotics were evaluated. Two obtained transformed clones (RJ 9 and 30) exhibited the incorporation of the entire bacterial T-DNA into genomic DNA, while clones RJ 10 and 11 demonstrated only the presence of the LT-DNA sequence. The results demonstrated an increase in flawan-3-ols (catechins) accumulation in hairy root tissue relative to non-transformed (NT) plants. Moreover, hairy roots exhibited enhanced antioxidant activity and bactericidal properties compared with NT roots and NT shoots, respectively.

For the first time, adventitious and hairy root cultures of Salvia apiana (white sage) have been established and analyzed for the content of secondary metabolites. Non-transformed roots derived from sterile seedlings were maintained on a full-strength IBA-supplemented SH medium. Adventitious roots yielded up to 44.5 mg/g and 18.7 mg/g DW rosmarinic acid when grown in shake flasks and immersion-column bioreactors, respectively. Transformed root cultures were established from S. apiana microshoots, infected with A4 and LBA9402 strains of Rhizobium rhizogenes. The obtained hairy root cultures (three and two clonal lines established using A4 and LBA9402 strains, respectively) were maintained in the PGR-free, full-strength SH medium. The most productive root line, established using A4 strain, accumulated rosmarinic acid at 38.1 and 39.6 mg/g DW when grown in shake flasks and spray bioreactors, respectively. Neither adventitious nor transformed roots of S. apiana produced diterpenoids, identified in roots of the field-grown plants, and instead proved to be a selective source of rosmarinic acid.

Reynoutria japonica Houtt. (Japanese knotweed) is an invasive plant belonging to the Polygonaceae family. However, being native to East Asia, it has been used in natural medicine for ages because of its broad range of biological activity. Although R. japonica is known as a rich source of phenolic compounds, plant biomass collected from the field may be contaminated with toxic elements like heavy metals, and the level of metabolite accumulation depends on environmental conditions. Therefore, the aim of this study was to derive Japanese knotweed tissue cultures and investigate biomass production and phenolic compound synthesis in in vitro conditions. Plants were cultivated in a traditional agar-solidified medium, in a liquid medium with rotary shaking (agitated culture), and in a temporary immersion bioreactors Plantform™, as well as in soil (ex vitro conditions). Analyses of the growth index and dry weight accumulation were performed on the collected material. In the extracts obtained from examined plants, qualitative and quantitative analysis of phenolic derivatives using DAD-HPLC was conducted to determine the sum of phenolic compounds, as well as the quantity of selected phenolic acids, catechins, and other flavonoids. Results have shown that agitated cultures and temporary immersion bioreactors increased biomass accumulation compared to solid medium cultures. Tissue cultures of R. japonica had increased synthesis of phenolic compounds compared to plants from ex vitro conditions. Shoots and roots from agitated cultures were 2.8- and 3.3-fold richer in catechins, respectively, compared to plants cultivated in soil. Based on the obtained results it can be concluded that agitated and bioreactor cultures are the best source of Japanese knotweed biomass rich in valuable secondary metabolites. Reynoutria japonica Houtt. plants in agitated culture and temporary immersion bioreactor are a rich source of flavonoids, including catechin derivatives.

Purpose: Although it is well known that the size, shape, and surface chemistry affect the biological potential of silver nanoparticles (AgNPs), the published studies that have considered the influence of AgNP surface on antibacterial activity have not provided conclusive results. This is the first study whose objective was to determine the significance of the surface net charge of AgNPs on their antibacterial potential, attraction to bacterial cells, and cell envelope disruption, considering differences in bacterial surface properties. Methods: We evaluated five commercial AgNP colloids with identical size and shape but different surface ligands. We thoroughly characterized their physicochemical properties, including the zeta potential, hydrodynamic diameter, and polydispersity index, and determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), along with silver absorption into bacterial cells. Moreover, we investigated structural changes in bacteria treated with AgNPs by using a crystal violet assay and electron microscopy. Results: The zeta potential of AgNPs ranged from -47.6 to +68.5 mV, with a hydrodynamic diameter of 29-87 nm and a polydispersity index of 0.349-0.863. Bacterial susceptibility varied significantly (0.5 <= MIC <= 256 mu g Ag/mL; 1 <= MBC <= 256 mu g Ag/mL); we found the lowest susceptibility in bacteria with a cell wall or a polysaccharide capsule. The most active AgNPs (0.5 <= MIC <= 32 mu g Ag/mL; 2 <= MBC <= 64 mu g Ag/mL) had a moderate surface charge (-21.5 and +14.9 mV). The antibacterial potential was unrelated to ion dissolution or cell envelope disruption, and bacterial cells absorbed less of the most active Conclusion: Contrary to previous reports, we found that a moderate surface charge is crucial for the antibacterial activity of AgNPs, and that a significant attraction of the nanoparticle to the cell surface reduces the antibacterial potential of AgNPs. These findings challenge the existing views on AgNP antibacterial mechanisms and interactions with bacterial cells.

The investigation aimed to assess three methods for inducing resistance in Solanum tuberosum L. (potato) plants against Soft Rot Pectobacteriaceae (SRP) bacteria. The approaches involved the incorporation of elicitors into the in vitro nutrient medium during plant cultivation, pre-planting of seeds soaked in water-containing elicitors, and irradiating in vitro cultivated potato plants with 21 kJ/m2 of ultraviolet C light (UVC). The research validated the authors’ hypothesis, that the use of specific elicitors and UV-C light could induce resistance in potato plants against SRP bacteria, identifying the most effective elicitation technique for potato plants under experimental conditions. Two elicitors, specifically 50 μM salicylic acid and 250 μg/mL proline, were determined to be the most potent under experimental conditions. Supplementation of the Murashige and Skoog medium (MS) with 50 μM salicylic acid resulted in 21

Dickeya solani, belonging to the Soft Rot Pectobacteriaceae, are aggressive necrotrophs, exhibiting both a wide geographic distribution and a wide host range that includes many angiosperm orders, both dicot and monocot plants, cultivated under all climatic conditions. Little is known about the infection strategies D. solani employs to infect hosts other than potato (Solanum tuberosum L.). Our earlier study identified D. solani Tn5 mutants induced exclusively by the presence of the weed host S. dulcamara. The current study assessed the identity and virulence contribution of the selected genes mutated by the Tn5 insertions and induced by the presence of S. dulcamara. These genes encode proteins with functions linked to polyketide antibiotics and polysaccharide synthesis, membrane transport, stress response, and sugar and amino acid metabolism. Eight of these genes, encoding UvrY (GacA), tRNA guanosine transglycosylase Tgt, LPS-related WbeA, capsular biosynthesis protein VpsM, DltB alanine export protein, glycosyltransferase, putative transcription regulator YheO/PAS domain-containing protein, and a hypothetical protein, were required for virulence on S. dulcamara plants. The implications of D. solani interaction with a weed host, S. dulcamara, are discussed.

Sundews (Drosera sp.) are the source of biologically active secondary metabolites: phenolic acids, flavonoids, and 1,4-naphtoquinones. Because obtaining them from the natural environment is impossible (rare and endangered species), in this study modifications of traditional tissue cultures grown in solid medium (SM), such as agitated cultures (ACs) (cultures in liquid medium with rotary shaking) and temporary immersion bioreactors PlantformTM (TIB), were used for multiplication of four sundew species: Drosera peltata, Drosera indica, Drosera regia, and Drosera binata, with simultaneously effective synthesis of biologically active phenolic compounds. Each species cultivated on SM, AC, and TIB was tested for biomass accumulation, the content of total phenols and selected phenolic derivative concentrations (DAD-HPLC), the productivity on of phenolic compounds, as well as its antibacterial activity against two human pathogens: Staphylococcus aureus and Escherichia coli. The results showed that the type of culture should be selected for each species separately. Phytochemical analyses showed that the synthesis of secondary metabolites from the groups of phenolic acids, flavonoids, and 1,4-naphthoquinones can be increased by modifying the cultivation conditions. D. regia turned out to be the richest in phenolic compounds, including 1,4-naphtoquinones: plumbagin and ramentaceone. Extracts from D. indica and D. regia tissue showed strong antibacterial activity against both pathogens. It has also been shown that the growth conditions of sundews can modify the level of secondary metabolites, and thus, their biological activity.

Changes in immunocompetent cells influence the course of diabetes mellitus and contribute to its complications. Thus, correction of diabetes-induced immune system disorders is vital for normalizing the state of the organism. Red wine polyphenols due to their biological activities could be considered a potential remedy for correcting diabetes. The study aimed to evaluate the antimicrobial potential and the influence of red wine polyphenols on immune system in streptozotocin-induced diabetes. We studied immunological parameters, i.e. quantity of white blood cells in peripheral blood and peritoneal macrophages, the bactericidal activity of phagocytes of blood, the activity of myeloperoxidase, and the level of cationic proteins in these cells after the administration of the polyphenol-rich red wine concentrate (PC concentrate) of known composition, obtained from Ukrainian wine, for 14th day to rats with streptozotocin-induced diabetes. The Minimal Bactericidal Concentration (MBC) of the PC concentrate was determined with the Broth Microdilution method. The PC concentrate normalized the quantity and functional activity of peripheral blood neutrophils and peritoneal macrophages, and decreased the quantity of lymphocytes under diabetes, as well as possessed the antibacterial activity against Staphylococcus aureus and Escherichia coli. Our results indicate the significant biological potential of the PC concentrate and its therapeutic relevance to correct diabetes-induced disorders.

Filaggrin (FLG) protein is indispensable for multiple aspects of the epidermal barrier function but its accumulation in a monomeric filaggrin form may initiate premature keratinocytes death; it is unclear how filaggrin levels are controlled before the formation of storing keratohyalin granules. Here we show that keratinocyte-secreted small extracellular vesicles (sEVs) may contain filaggrin-related cargo providing a route of eliminating excess filaggrin from keratinocytes; blocking of sEV release has cytotoxic effects on those cells. Filaggrin-containing sEVs are found in plasma in both healthy individuals and atopic dermatitis patients. Staphylococcus aureus (S. aureus) enhances packaging and secretion of filaggrin-relevant products within the sEVs for enhanced export via a TLR2-mediated mechanism which is also linked to the ubiquitination process. This filaggrin removal system, preventing premature keratinocyte death and epidermal barrier dysfunction, is exploited by S. aureus which promotes filaggrin elimination from the skin that could help safeguard bacterial growth.

Accumulation of medicinally important flavones and acteoside was evaluated in Scutellaria lateriflora hairy root cultures subjected to different experimental strategies – feeding with precursors of phenolics biosynthesis (phenylalanine, cinnamic acid, and sodium cinnamate), addition of elicitors (chitosan, jasmonic acid) and Amberlite XAD-4 and XAD-7 resins and permeabilization with dimethyl sulfoxide (DMSO) and methanol. The production profile of S. lateriflora cultures changed under the influence of the applied strategies. Hairy roots of S. lateriflora were found to be a rich source of wogonoside or wogonin, depending on the treatment used. The addition of sodium cinnamate (1.0 mg/L) was the most effective approach to provide high production of flavonoids, especially wogonoside (4.41% dry weight /DW/; 566.78 mg/L). Permeabilization with DMSO (2 µg/ml for 12 h) or methanol (30% for 12 h) resulted in high biosynthesis of wogonin (299.77 mg/L and 274.03 mg/L, respectively). The obtained results provide new insight into the selection of the optimal growth conditions for the production of in vitro biomass with a significant level of flavone accumulation. The data may be valuable for designing large-scale cultivation systems of hairy roots of S. lateriflora with high productivity of bioactive compounds – wogonin or wogonoside.

The aim of this work was the evaluation of biological properties of hybrid coatings modified with Ag, Cu, and Zn nanoparticles (NPs) applied on TPLO medical implants by the sol-gel process. The implant coatings enriched with various concentrations of metallic NPs were investigated in the in vitro bactericidal efficacy tests against Gram+ and Gram- bacteria and pathogenic yeast. Next, the designed materials were tested on human osteosarcoma cell lines. The cells adhesion, proliferation, viability, and differentiation were investigated. The cell growth wasevaluated using SEM, and the metallic ion release was measured. The results revealed that the NPs concentration in the hybrid layers decreased with the incubation time. In the last stage, the implants were tested in vivo on six canine patients. Three months after the operation, the radiological evaluation of the performed anastomosis was carried out as well as the histopathological evaluation of tissue regeneration. The strongest bactericidal efficacy was observed for the layers containing AgNPs. Along with an increased concentration of metallic additives, a growing toxic effect was clearly observed. The most pronounced toxic effect was especially evident with the AgNPs concentration exceeding 1 mol %. In all the operated patients, no deviations were found during the follow-up examinations in the postoperative period. The low dose of AgNPs in the hybrid layer facilitated the tissue healing process. It was proven that silver nanoparticles may accelerate the bone healing process. The correct tissue reparation was observed.

Pontechium maculatum (Russian bugloss) is a medical plant belonging to the family Boraginaceae. Although this species is known as a medical plant rich in biologically active secondary metabolites, biotechnological studies about this valuable plant is still missing. The scientific objectives of this study were to investigate the biomass production, synthesis, and productivity of various phenolic acids, flavonoids, and shikonin in P. maculatum cultivated in various breeding systems. Additionally, the antioxidant activity of plant-derived extracts was evaluated. Plants were cultivated in a traditional agar-solidified medium, a liquid medium with rotary shaking, and a temporary immersion bioreactors Plantform™ (TIB), as well as cultivated in soil (ex vitro conditions). Analyses of the growth index and dry weight accumulation were performed on the collected material. In the extracts obtained from examined plants, total phenolic content was estimated, and qualitative and quantitative analysis of phenolic derivatives using DAD-HPLC was conducted, simultaneously with an analysis of antioxidant capacity. TIB stimulated the highest synthesis of all examined phenolic acids and shikonin. In TIB-cultivated shoots level of rosmarinic acid obtained a concentration of 3160.76 mg × 100 g − 1 dry weight (DW), and shikonin obtained a concentration of 77.26 mg × 100 g − 1 DW. Furthermore, plants from TIB were characterized by the highest productivity of all studied phenolic derivatives, what makes it very effective platform for the synthesis of biologically active secondary metabolites in Russian bugloss. Moreover, this article shows that P. maculatum is a rich source of various phenolic derivatives with high antioxidant potential.

Candida albicans (C. albicans) infection is a potential complication in the individuals with atopic dermatitis (AD) and can affect clinical course of the disease. Here, using primary keratinocytes we determined that atopic milieu promotes changes in the interaction of small extracellular vesicles (sEVs) with dendritic cells and that this is further enhanced by the presence of C. albicans. sEV uptake is largely dependent on the expression of glycans on their surface; modelling of the protein interactions indicated that recognition of this pathogen through C. albicans-relevant pattern recognition receptors (PRRs) is linked to several glycosylation enzymes which may in turn affect the expression of sEV glycans. Here, significant changes in the surface glycosylation pattern, as determined by lectin array, could be observed in sEVs upon a combined exposure of keratinocytes to AD cytokines and C. albicans. This included enhanced expression of multiple types of glycans, for which several dendritic cell receptors could be proposed as binding partners. Blocking experiments showed predominant involvement of the inhibitory Siglec-7 and -9 receptors in the sEV-cell interaction and the engagement of sialic acid-containing carbohydrate moieties on the surface of sEVs. This pointed on ST6 β-Galactoside α-2,6-Sialyltransferase 1 (ST6GAL1) and Core 1 β,3-Galactosyltransferase 1 (C1GALT1) as potential enzymes involved in the process of remodelling of the sEV surface glycans upon C. albicans exposure. Our results suggest that, in combination with atopic dermatitis milieu, C. albicans promotes alterations in the glycosylation pattern of keratinocyte-derived sEVs to interact with inhibitory Siglecs on antigen presenting cells. Hence, a strategy aiming at this pathway to enhance antifungal responses and restrict pathogen spread could offer novel therapeutic options for skin candidiasis in AD.

Plant cell and organ cultures are potential sources of valuable secondary metabolites that can be used as food additives, nutraceuticals, cosmeceuticals, and pharmaceuticals. Phytochemical biosynthesis in various in vitro plant cultures, in contrast to that in planta, is independent of environmental conditions and free from quality fluctuations. Pharmaceutical application of plant biotechnology is of interest to almost all departments of the Faculty of Pharmacy and Institute of Pharmacology in Poland with a botanical profile (Pharmaceutical Botany, Pharmacognosy, and Pharmacology). This study discusses the advances in plant biotechnology for the production of known metabolites and/or biosynthesis of novel compounds in plant cell and organ in vitro cultures in several scientific centers in Poland.

Dionaea muscipula J. Ellis is a South and North Carolina carnivorous endemic plant with medicinal properties. Its natural habitat is characterized by low availability of nutrients and poor plant cover, resulting in Venus flytrap exposure to various stress factors (especially UV-A radiation). To evaluate the response of Dionaea muscipula photosynthetic apparatus to increased levels of UV-A radiation, plants cultivated in controlled conditions (30–40 % air humidity, temperature 23 ± 1 °C, light intensity 290 μmol m–2 s–1, 16 h light/8 h dark) (Control) were treated additionally with 50 μmols m–2s–1 UV-A radiation for 24 h (Treated). Measurements of gas exchange, chlorophyll fluorescence and photosynthetic pigment content were conducted immediately after the exposure, both in the Control and Treated plants. Additionally, the same parameters were evaluated in the next 24 hours (Recovery). UV-A treatment (Treated) did not change chlorophyll a + b content and chlorophyll a/b ratio. Furthermore, an increased level of electron carriers (Area, Sm) and increased efficiency of electron transport between QA and PSI (ΦR0, δR0, ρR0) was observed. Further, PSI and electron acceptors demonstrated an increased ability to oxidize reduced plastoquinone pool (VI decrease). As a consequence, the rate of net photosynthesis increased significantly. After 24h from the exposure (Recovery), the chlorophyll a + b content declined but the ratio of chlorophyll a/b did not alter, which indicates a decrease in the size of photosynthetic antennas and the number of active PSII centers. Additionally, inactivation of the reaction centers (F0 decrease, VJ and VI increase) and a decrease in the amount of electron carriers, especially PQ poll (Sm), was observed. Moreover, a decrease of electron flux and efficiency of electron transport between QA and PSI occurred (decrease of: ΦE0, ψE0, ET0/RC, ET0/CS0, ΦR0, ρR0). These results may indicate the decrease of PSII photochemical efficiency. Simultaneously, PSI reactions remained unchanged and the rate of net photosynthesis increased significantly. This can be connected with the activation of alternative pathways of electron transport. Activation of these pathways leads to the limitation of NADPH synthesis and an increase in ATP synthesis, what enables the plant’s effective acclimatization to stress conditions.

Antibiotic resistance is a global problem, and one promising solution to overcome this issue is using metallodrugs, which are drugs containing metal ions and ligands. These complexes are superior to free ligands in various characteristics including anticancer properties and mechanism of action. The pharmacological potential of metallodrugs can be modulated by the appropriate selection of ligands and metal ions. A good example of proper coordination is the combination of sulfonamides (sulfamerazine, sulfathiazole) with a ruthenium(III) ion. This work aimed to confirm that the activity of sulfonamides antibacterial drugs is initiated and/or stimulated by their coordination to an Ru(III) ion. The study determined the structure, electrochemical profile, CT-DNA affinity, and antimicrobial as well as anticancer properties of the synthesized complexes. The results proved that Ru(III) complexes exhibited better biological properties than the free ligands.

Carnivorous plants are exemplary natural sources of secondary metabolites with biological activity. However, the therapeutic antimicrobial potential of these compounds is limited due to intrinsic resistance of selected bacterial pathogens, among which Pseudomonas aeruginosa represents an extreme example. The objective of the study was to overcome the intrinsic resistance of P. aeruginosa by combining silver nanoparticles (AgNPs) with secondary metabolites from selected carnivorous plant species. We employed the broth microdilution method, the checkerboard titration technique and comprehensive phytochemical analyses to define interactions between nanoparticles and active compounds from carnivorous plants. It has been confirmed that P. aeruginosa is resistant to a broad range of secondary metabolites from carnivorous plants, i.e., naphthoquinones, flavonoids, phenolic acids (MBC = 512 µg mL−1) and only weakly sensitive to their mixtures, i.e., extracts and extracts’ fractions. However, it was shown that the antimicrobial activity of extracts and fractions with a significant level of naphthoquinone (plumbagin) was significantly enhanced by AgNPs. Our studies clearly demonstrated a crucial role of naphthoquinones in AgNPs and extract interaction, as well as depicted the potential of AgNPs to restore the bactericidal activity of naphthoquinones towards P. aeruginosa. Our findings indicate the significant potential of nanoparticles to modulate the activity of selected secondary metabolites and revisit their antimicrobial potential towards human pathogenic bacteria.