Dry rose extract (DRE) obtained industrially by aqueous ethanol extraction from R. damascena flowers and its phenolic-enriched fraction, obtained by re-extraction with ethyl acetate (EAE) were the subject of this study. ¹H NMR of DRE allowed the identification and quantitation of fructose and glucose, while the combined use of HPLC-DAD-ESIMS and HPLC-HRMS showed the presence of 14 kaempferol glycosides, 12 quercetin glycosides, 4 phenolic acids and their esters, 4 galloyl glycosides, 7 ellagitannins, and quinic acid. In addition, the structures of 13 of the flavonoid glycosides were further confirmed by NMR. EAE was found to be richer in TPC and TFC and showed better antioxidant activity (DPPH, ABTS, and FRAP) compared to DRE. Both extracts displayed significant activity against Propionibacterium acnes, Staphylococcus aureus, and S. epidermidis, but showed no activity against Candida albicans. Toxicity tests on normal human skin fibroblasts revealed low toxicity for both extracts with stronger effects observed at 24 hours of treatment that were compensated for over the following two days. Human hepatocarcinoma (HepG2) cells exhibited an opposite response after treatment with a concentration above 350 µg/mL for EAE and 500 µg/mL for DRE, showing increased toxicity after the third day of treatment. Lower concentrations were non-toxic and did not significantly affect the cell cycle parameters of either of the cell lines.

We investigated the influence of different rootstocks on the content of sugars, organic acids, and antioxidant phenolic compounds in the whole fruit and fruit skin of the European plum cultivar “Čačanska Lepotica”. ¹H NMR of the fruit extracts allowed for the identification of sucrose, α- and β-glucose, sorbitol, fructose, and malic and quinic acids, while LC–DAD–ESIMS showed the presence of neochlorogenic and chlorogenic acids, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, peonidin-3-O-rutinoside, hyperoside, isoquercitrin, rutin, and unidentified quercetin-3-diglycoside. The quantitation of the sugars, malic and quinic acids by ¹H NMR and phenolic compounds by HPLC–DAD revealed that the rootstock significantly influenced the content of the individual compounds in the fruit skin and fruit. The fruit grafted on “Wavit” rootstock was characterized by significant amounts of neochlorogenic acid, peonidin-3-O-rutinoside, cyanidin-3-O-rutinoside, and sucrose, while the fruit on “GXN-15” was characterized by high levels of sugars, cyanidin-3-O-glucoside, and malic and chlorogenic acids. The fruit skins of plums grafted on “Wavit” were the richest in sugars, organic acids, and phenolic compounds. A good correlation was observed between the content of total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and individual phenolic compounds in the extracts of the fruit and the fruit skins and their antioxidant capacity (DPPH, ABTS, and FRAP).

The food industry is interested in replacing artificial sweeteners with natural sugars that possess zero calories and carbohydrates and do not cause spikes in blood sugar levels. The steviosides leaves, synthesized at Stevia rebaudiana Bertoni, are 300 times sweeter than common table sugar. Stevia propagation is limited due to the poor viability of the seeds, the long time and low germination rate, and the poor rooting ability of vegetative cuttings. Because of this, an alternative biotechnological method for its reproduction is being studied, such as multiple shoot production through direct organogenesis using nanofibers, formed from a derivative of amino acid valine as a carrier of the biologically active agent silver atoms/particles (NF-1%Ag and NF-2%Ag). The stevia explants were cultured on a medium containing NF-1%Ag and NF-2%Ag at concentrations of 1, 10, 50, and 100 mg L⁻¹. The NF-1%Ag and NF-2%Ag treatment caused hormetic effects on stevia plantlets. At low concentrations of from 1 to 50 mg L⁻¹ of nanofibers, the stimulation of plant growth was observed, with the maximum effect being observed at 50 mg L⁻¹ nanofibers. However, at the higher dose of 100 mg L⁻¹, inhibition of the values of parameters characterizing plant growth was recorded. The presence of nanofibers in the medium stimulates stevia root formatting.

The formation of microbial biofilm is a self-organizing process among bacterial cells, regulated by quorum-sensing (QS) mechanisms, contributing to development of infections. These processes, either separately or in combination, significantly contribute to bacterial resistance to antibiotics and disinfectants. A novel approach to addressing the challenge of treating infections due to antibacterial resistance involves the use of plant metabolites. In recent years, there has been increasing recognition of different phytochemicals as potential modulators. In our study, we evaluated the synergistic effect of chloroform and methanol extracts from Inula species against key virulence factors, including biofilm formation, violacein production, and swarming motility. Each of the 11 examined plant extracts demonstrated the ability to reduce biofilms and pigment synthesis in C. violaceum. Two of the extracts from I. britannica exhibited significant anti-biofilm and anti-quorum-sensing effects with over 80% inhibition. Their inhibitory effect on violacein synthesis indicates their potential as anti-QS agents, likely attributed to their high concentration of terpenoids (triterpenoids, sesquiterpene lactones, and diterpenoids). Scanning electron microscopy revealed a notable reduction in biofilm biomass, along with changes in biofilm architecture and cell morphology. Additionally, fluorescence microscopy revealed the presence of metabolically inactive cells, indicating the potent activity of the extracts during treatment. These new findings underscore the effectiveness of the plant extracts from the genus Inula as potential anti-virulent agents against C. violaceum. They also propose a promising strategy for preventing or treating its biofilm formation.

Arnica montana L. is an important herbal medicinal plant that belongs to the family Asteraceae. This plant has been known for its medicinal uses for centuries. A. montana exhibits several pharmacological properties, including immunomodulatory, anti-inflammatory, anticancer, antioxidant, and antibacterial effects. For the first time, the impacts of the biotic elicitor yeast extract, and the abiotic elicitor salicylic acid on micropropagation, antioxidant potential, and accumulation of caffeoylquinic acids in arnica in vitro shoots were assessed. The results showed that yeast extract applied at 100 mg/L significantly promotes shoot multiplication, biomass yield, total phenolic content, and synthesis of caffeoylquinic acids compared to control untreated shoots. Flavonoid content was the highest in samples treated with 200 mg/L of yeast extract, although at this concentration the measured biometric parameters began to decrease. Salicylic acid at 100 µM was found to be effective in the induction of vigorous shoots, shoot height growth, and biomass accumulation; nevertheless, this elicitor downregulated the caffeoylquinic acid level, total phenolics, and flavonoids. Increasing the concentration of salicylic acid to 200 µM caused shoot multiplication and fresh biomass accumulation reduction. Both elicitors modulated the activity of antioxidant enzymes against oxidative stress. Overall, the use of these substances can improve the growth and biomass yield in Arnica in vitro shoots.

GC-MS/FID analysis of the essential oils of 10 Thymus species, belonging to Sect. Serpyllum, led to identification of 118 compounds accounting for 97.79–99.69% of the total oil. Thymus moesiacus, T. jankae, T. vandasii, T. longicaulis and T. sibthorpii were characterized by the presence of linalool (19.37–35.21%) as the major or dominant component, but differed significantly in the content of the other prominent components: linalyl acetate, geraniol, geranyl acetate, α-terpinyl acetate, myrcen-8-yl acetate, myrcen-8-ol, etc. α-Terpinyl acetate (66.79%), thymol (63.96%), carvacrol (42.65%) and germacrene D (42.15%) were the principal components of T. pulegioides, T. glabrescens, T. callieri and T. pannonicus, respectively. β-Myrcene (16.53%), cis-sabinene hydrate (13.58%), τ-cadinol (13.24%) and elemol (11.29%) determined the oil from T. thracicus as a mixed mono-/sesquiterpene chemotype. The obtained results revealed the existence of new chemotypes of T. moesiacus, T. thracicus, T. sibthorpii and T. longicaulis. The essential oil content of T. callieri and endemic T. vandasii is reported for the first time. The variations in the essential oils of different Thymus species from Sect. Serpyllum were examined by principal component analysis (PCA) and cluster analysis (CA).