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The study explores the novel use of oak bark (Quercus cortex) as a bio-filler in elastomeric composites, aligning with the global trend of plant-based biocomposites. Both modified and unmodified oak bark were investigated for their impact on the physicochemical properties of natural rubber (NR) composites. The bio-filler modified with n-octadecyltrimethoxysilane exhibited enhanced dispersion and reduced aggregates in the elastomeric matrix. NR composites containing more than 20 phr of unmodified and modified oak bark demonstrated an increased degree of cross-linking (αc > 0.21). Mechanical properties were optimal at 10–15 phr of oak bark and the sample with modified bio-filler (10 phr) achieved the highest tensile strength (15.8 MPa). Silanization and the addition of the bio-filler increased the hardness of vulcanizates. The incorporation of oak bark improved aging resistance at least two-fold due to phenolic derivatives with antioxidant properties. Hydrophobicity decreased with added bark, but silanization reversed the trend, making samples with a high content of oak bark the most hydrophobic (contact angle: 129°). Overall, oak bark shows promise as an eco-friendly, anti-aging filler in elastomeric composites, with modification enhancing compatibility and hydrophobicity. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we tested the potential of a wormwood and oak bark-based dietary supplement for Nosema ceranae infection control and health improvement of infected honey bees. Results revealed a very good anti-Nosema effect and, consequently, the reduction of Nosema-induced oxidative stress and immunosuppression. Keeping in mind the absence of adequate anti-Nosema treatment, this supplement could be of great importance in the beekeeping sector, especially because of its ecologically friendly (plant-based) nature. Motivated by the results of this study, we plan to conduct further experiments to improve knowledge about the effects and mechanisms included in bee health improvement with the tested supplement. Nosema ceranae, a microsporidian parasite, as one of the stressors that contribute to honey bee decline, has a significant negative impact on the longevity, productivity, and reproductive capacity of honey bee colonies. There are several different strategies for Nosema infection control, including natural-based and antibiotic-based products. In this study, we tested wormwood and oak bark-based supplement "Medenko forte" on survival, Nosema infection, oxidative stress, and expression of immune-related genes in artificially N. ceranae-infected bees. The results revealed a positive influence on the survival of Nosema-infected bees, irrespectively of the moment of supplement application (day 1, day 3, or day 6 after bee emergence), as well as reduction of Nosema loads and, consequently, Nosema-induced oxidative stress. Supplementation had no negative effects on bee immunity, but better anti-Nosema than immune-stimulating effects were affirmed based on expression levels of abaecin, defensin, hymenoptaecin, apidaecin, and vitellogenin genes. In conclusion, the tested supplement "Medenko forte" has great potential in the health protection of Nosema-infected bees. However, further investigations need to be performed to elucidate its mechanisms of action. [ABSTRACT FROM AUTHOR]

Background and Aim: Bovine mastitis has a negative impact on animals, and improper antibiotic use has caused an increase in bacterial resistance. Therefore, medicinal plants could serve as an alternative treatment for this condition. Polyphenols have potential as antibiotic agents. Oak bark has long been used as a medicine and has shown antibacterial effects. Moreover, research on heather plant demonstrated that it has antibacterial properties. This study aimed to assess the antibacterial effects of oak (Quercus robur) bark and heather (Calluna vulgaris L.) herb extracts against common bovine mastitis pathogens. Materials and Methods: Dried oak bark and heather herb were used to prepare extracts using 30%, 50%, and 70% ethanol and acetone as solvents. Their polyphenol content was determined using the Folin-Ciocalteu method. Bovine mastitisinducing clinical isolates of Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli were used for antibacterial tests. All extracts were screened through a disk diffusion test to ascertain their antibacterial effects, and the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined for the most effective extracts. Results: Oak bark extracts had variable antibacterial effects against S. aureus and Streptococcus strains, but no statistically significant difference was observed in activity against E. coli. The disk diffusion test showed that the oak bark extracts obtained using acetone and ethanol at 30% yielded the best results. However, the 70% acetone oak extract alone affected all types of bacteria. Further antibacterial tests of 70% acetone and 30% ethanol oak extracts revealed that the lowest MIC and MBC scores were against S. aureus strains and E. coli reference cultures. Conversely, the heather herb extracts exhibited broader activity against all types of bacteria, although better results were observed against Gram-positive bacteria. There was also a negative correlation between solvent concentration and antibacterial effect (p < 0.05, r = -0.507). The highest inhibition zone scores and broadest spectrum were observed in samples prepared in 30% ethanol. There was no statistically significant correlation between the phenolic content of plants and their antibacterial effects. Conclusion: Oak bark and heather extracts could be used as potential antibacterial agents against bovine mastitis pathogens. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to compare the effect of two plant additives, rich in polyphenolic compounds, supplemented to sheep diets on microorganisms and carbohydrate fermentation in rumen. Methods: In the experiment, 6 ewes of the Polish Mountain breed were fitted with ruminal cannulas. Sheep were divided into three feeding groups. The study was performed in a crossover design of two animals in each group, with three experimental periods (n = 6 per each group). The animals were fed a control diet (CON) or additionally received 3 g of dry and milled lingonberry leaves (VVI) or oak bark (QUE). Additionally, plant material was analyzed for tannins concentration. Results: Regardless of sampling time, QUE diet increased the number of total protozoa, as well as Entodinium spp., Diplodinium spp. and Isotrichidae family, while decreased bacterial mass. In turn, a reduced number of Diplodinium spp. and increased Ophryoscolex spp. population were noted in VVI fed sheep. During whole sampling time (0, 2, 4, and 8 h), the number of protozoa in ruminal fluid of QUE sheep was gradually reduced as opposed to animals receiving CON and VVI diet, where rapid shifts in the protozoa number were observed. Moreover, supplementing sheep with QUE diet increased molar proportions of butyrate and isoacids in ruminal fluid. Unfortunately, none of the tested additives affected gas production. Conclusion: The addition of VVI or QUE in a small dose to sheep diets differently affected rumen microorganisms and fermentation parameters, probably because of various contribution of catechins in tested plant materials. However, it is stated that QUE diet seems to create more favorable conditions for growth and development of ciliates. Nonetheless, the results of the present study showed that VVI and QUE additives could serve as potential natural modulators of microorganism populations and, consequently, carbohydrate digestion in ruminants. [ABSTRACT FROM AUTHOR]

Residues of wood, such as bark, represent an attractive source for natural antioxidants. The aim of this study was to evaluate the total polyphenols, heavy metals content and antioxidant capacity from oak (Quercus robur L.) and pine (Pinus sylvestris L.) barks grown in the central region of Poland. Identification and quantification of flavonoids and phenolic acids were done by HPLC-MS analysis. The phenolic extraction yields for oak barks were higher than for pine barks, while higher content of total flavonoids was determined in pine bark extracts. Generally, the content of the metals in raw barks and their extracts decreased in the order: Zn > Cu > Cr > Pb > Ni > Cd. The extracts were able to quench DPPH· radicals and to reduce the cupric complex exhibiting good antioxidant properties. They can be utilised as additives in nutraceutical and cosmetic products as well as for wood preservative materials. [ABSTRACT FROM AUTHOR]

Development and validation of a new technique for direct spectrophotometric quantitative determination of high- and low-molecular-mass tannins are reported. The proposed method enables simultaneous codetermination using Firordt calculations of tannins and gallic acid in medicinal plant raw material and herbal preparations without preliminary separation from complicated mixtures with other biologically active compounds found in the plant extracts. The developed method was validated (using nettle raw material as an example). The contents of gallic acid and tannins in the samples were (1.20 ± 0.04)% and (1.52 ± 0.03)%, respectively, which agreed with literature data. [ABSTRACT FROM AUTHOR]

Bark as a biowaste has a huge availability throughout the world and has had limited use in industrial applications. Black pine bark and oak bark were considered in this work. The aim was to manufacture a new biocomposite with different combination of black pine bark, oak bark, polypropylene, polyethylene, and a coupling agent, and to determine some physical and mechanical properties of the manufactured biocomposites. Density, thickness swelling, water absorption, tension strength, modulus of rapture and modulus of elasticity in bending and tension of the biocomposites were determined. According to the results, thickness swelling and water absorption properties were improved up to 80% when compared with wood-plastic composites (WPC) produced with wood flour. Although the new biocomposites displayed lower mechanical performance in comparison of biocomposites made with wood flour, the observed results were satisfactory. Based on the results of this study, black pine bark and oak bark can be used as filler materials in WPCs production. Hereby, these bark materials can be the raw material for value-added products. Bark use in biocomposite production also can contribute to reduced requirements of wood material and petroleum products. [ABSTRACT FROM AUTHOR]

Airborne 137 Cs originated from the nuclear tests in the atmosphere and from the Chernobyl nuclear disaster was retained by the trees biomass and nowadays it can still be found in various concentrations in tree barks from Romania and other European countries. This study brings the first results of 137 Cs presence in tree bark from Romania on different considerations: (i) data dispersion in spruce and oak bark from NW, SW and central Romania, and the spatial variability of 137 Cs within oak and spruce bark from a natural protected forest area from Balvanyos area (Covasna County), known to be highly affected by the Chernobyl nuclear release; (ii) comparison of 137 Cs content in different tree bark species (oak, spruce, poplar and cherry); (iii) differences in 137 Cs concentrations with the bark depth layers and around the tree trunk; and (iv) comparison of mean 137 Cs values in spruce/oak bark from Romania with data from other European countries. [ABSTRACT FROM AUTHOR]

Abstract: In view of the lower radionuclide activities of moss and lichen, tree barks can be used as biomonitors of radioactive contamination, regardless of the contribution of soil uptake. The present study was conducted to determine the activity concentrations of 137Cs, 40K, 232Th and 238U in the barks of pine (Pinus nigra) and oak (Quercus petraea) trees collected from the Thrace region in Turkey. By considering the previous studies carried out in the same region, it is noticed that among lichen, moss, oak bark and pine bark, oak bark is the best accumulator of 137Cs and natural radionuclides. [Copyright &y& Elsevier]