A. mellea fruiting bodies collected from nature were chemically characterized and shown to be rich in carbohydrates (81.25 g per 100 g dw), ash, fat and proteins (8.84 g per 100 g dw, 1.97 g per 100 g dw and 1.81 g per 100 g dw, respectively). Mannitol was the main free sugar while malic acid was the most abundant organic acid. δ-Tocopherol was the dominant form of tocopherols with 42.41 μg per 100 g dw. Polyunsaturated fatty acids were predominant, followed by saturated and monounsaturated fatty acids. A methanolic extract prepared from these samples was tested for antioxidant, quorum sensing and antimicrobial assays, as well as for its cytotoxicity effects. The extract showed antimicrobial activity against all tested microorganisms, including Candida albicans. Furthermore, when tested at sub-MIC concentration, it showed reduction of virulence factors and biofilm formation against Pseudomonas aeruginosa. The extract also exhibited antioxidant activity and did not show toxicity against tumor and non-tumor cells. Due to the observed bioactive properties and compounds of the honey mushroom and its well-balanced nutrients, this mushroom emerges as an interesting functional food and a source of nutraceuticals with applications in different diseases based on antioxidant and antimicrobial effects.

Usnic acid, a dibenzofuran, was originally isolated from lichens producing secondary metabolites, and is well known as an antibiotic, but is also endowed with several other interesting properties. Thus, the goal of this paper is the design of new usnic acid derivatives and evaluation of their antimicrobial activity. All newly synthesized compounds possess good antibacterial activity with MIC ranging from 1.02–50.93 × 10⁻² mmol mL⁻¹ and MBC from 2.05–70.57 × 10⁻² mmol mL⁻¹. The most sensitive bacterial species was Staphylococcus aureus, while Pseudomonas aeruginosa and Escherichia coli were the most resistant among the ATCC strains, and MRSA was the most resistant among all tested bacteria (ATCC and clinical isolates). Their antifungal activity was very strong (MIC = 0.35–7.53 × 10⁻² mmol mL⁻¹ and MFC = 0.70–15.05 × 10⁻² mmol mL⁻¹) – better than those of reference compounds and usnic acid itself. The most sensitive fungal species was Trichoderma viride, while Penicillium versicolor var. cyclopium appeared to be the most resistant. It should be mentioned that in general most of the compounds showed weaker antibacterial activity, but better antifungal properties than usnic acid itself. The results allow us to conclude that the title compounds are good lead compounds for novel more active antibacterial drugs. On the other hand, these compounds are very promising as antifungals.

Plants are rich in bioactive phytochemicals that often display medicinal properties. These can play an important role in the production of health-promoting food additives and the replacement of artificial ones. In this sense, this study aimed to characterise the polyphenolic profile and bioactive properties of the decoctions, infusions and hydroethanolic extracts of three plants: lemon balm (Melissa officinalis L.), sage (Salvia officinalis L.) and spearmint (Mentha spicata L.). Total phenolic content ranged from 38.79 mg/g extract to 84.51 mg/g extract, depending on the extract. The main phenolic compound detected in all cases was rosmarinic acid. The results highlighted that some of these extracts may have the ability to prevent food spoilage (due to antibacterial and antifungal effects) and promote health benefits (due to anti-inflammatory and antioxidant capacities) while not displaying toxicity against healthy cells. Furthermore, although no anti-inflammatory capacity was observed from sage extracts, these stood out for often displaying the best outcomes in terms of other bioactivities. Overall, the results of our research provide insight into the potential of plant extracts as a source of active phytochemicals and as natural food additives. They also support the current trends in the food industry of replacing synthetic additives and developing foods with added beneficial health effects beyond basic nutrition.

Lonicera caerulea L. (haskap) berries are widely known for their richness in anthocyanins. In this study, such fruits were assessed for their nutritional and chemical composition, but also as sources of anthocyanins with great colouring properties to be applied in foodstuff. Haskap presented high levels of water, four free sugars (mainly fructose and glucose), five organic acids (mainly citric, malic, and quinic), α- and γ-tocopherol, twenty fatty acids (with prevalence of linoleic acid), and eight phenolic compounds, among which six were anthocyanins (mainly cyanidin-3-O-glucoside). The extract presented great antioxidant properties, evaluated through TBARS and OxHLIA assays, as well as antimicrobial capacity against six bacteria and six fungi. Two colourants were obtained by spray-drying haskap juice with maltodextrin and a mixture of maltodextrin and arabic gum. These formulations were stable over 12 weeks of storage at room and refrigerated temperature, without significant variations in colour parameters and in anthocyanins concentration. They were considered safe for consumption once neither microbial contamination nor cytotoxicity in non-tumour cells were detected. The results obtained allow for the consideration of haskap as a promising source of colourants to be applied not only in the food industry, but also in other fields that rely on artificial colourants.

Objectives: The chemical composition, antimicrobial and synergistic effect, and cytotoxic activity of Citrus limon (lemon), Piper nigrum (green pepper) and Melaleuca alternifoila (tea tree) essential oils (EOs) were investigated. Methods: Chemical analyses of essential oils were tested by GC-FID and GC-MS spectroscopy. The antimicrobial activity assay was conducted using microdilution method against several oral bacteria and Candida spp. originating from the humans with oral disorders. The synergistic antimicrobial activity was evaluated using checkerboard method. The cytotoxicity evaluation of EOs was assessed using MTT test. Key findings: Limonene (37.5%) and β-pinene (17.9%) were the major compounds in C. limon oil, β-pinene (34.4%), δ-3-carene (19.7%), limonene (18.7%) and α-pinene (10.4%) in P. nigrum oil and terpinen-4-ol (38.6%) and γ-terpinene (21.7%) in M. alternifolia oil. The broad-spectrum antimicrobial activity was achieved by tested three EOs, with C. limon oil being the strongest against bacteria and M. alternifolia oil strongest against fungi. The EOs demonstrated synergism; their combined application revealed an increase in antimicrobial activity. All tested essential oils showed lower cytotoxic activity in comparison with the positive control, and the obtained results confirmed a dose-dependent activity. Conclusions: The results of this study encourage use of tested EOs in development of a novel agent intended for prevention or therapy of corresponding oral disorders.