Nanoparticles are intensely studied because of their importance in diverse fields of biotechnology, especially in medicine. This paper highlights that waste bark can be a cheap source of biocompounds, with high recovery and functionalization potential in nanoparticle synthesis. Due to their biocompatibility and activity as antioxidant, antimicrobial, and anticancer agents, the green synthesis of metallic nanoparticles is of great importance. This review aims to bring together the diversity of synthesized metallic nanoparticles mediated by bark extracts obtained from different woody vascular plants, the phytoconstituents responsible for the reduction of metal salts, and the activity of metallic nanoparticles as diverse agents in combating the microbial, oxidant, and cancer activity. The literature data highlight the fact that metallic nanoparticles obtained from natural compounds are proven reducing agents with multiple activities. Thus, the activity of natural components in environmental protection and human health is confirmed.
The study of bimetallic nanoparticles (BNPs) has constantly been expanding, especially in the last decade. The biosynthesis of BNPs mediated by natural extracts is simple, low-cost, and safe for the environment. Plant extracts contain phenolic compounds that act as reducing agents (flavonoids, terpenoids, tannins, and alkaloids) and stabilising ligands moieties (carbonyl, carboxyl, and amine groups), useful in the green synthesis of nanoparticles (NPs), and are free of toxic by-products. Noble bimetallic NPs (containing silver, gold, platinum, and palladium) have potential for biomedical applications due to their safety, stability in the biological environment, and low toxicity. They substantially impact human health (applications in medicine and pharmacy) due to the proven biological effects (catalytic, antioxidant, antibacterial, antidiabetic, antitumor, hepatoprotective, and regenerative activity). To the best of our knowledge, there are no review papers in the literature on the synthesis and characterisation of plant-mediated BNPs and their pharmacological potential. Thus, an effort has been made to provide a clear perspective on the synthesis of BNPs and the antioxidant, antibacterial, anticancer, antidiabetic, and size/shape-dependent applications of BNPs. Furthermore, we discussed the factors that influence BNPs biosyntheses such as pH, temperature, time, metal ion concentration, and plant extract.
Processing wood leads to the accumulation of considerable amounts of forest waste, such as branches, leaves and especially bark. These byproducts can be exploited for their high content of biomolecules. Our aim was to histo-anatomically and phytochemically characterize the older oak bark and evaluate the potential biological activities. After the histo-anatomical characterization and processing the plant material, the aqueous and hydroalcoholic extracts were obtained using microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE). After the quantification of the total polyphenol content (TPC) and the total tannins content (TTC), the bark extracts were evaluated for antioxidant, antimicrobial and enzyme inhibitory activity. In the transverse section, the rhytidome (the succession of periderms) and the dead secondary phloem can be observed. The results of the polyphenol content of the oak bark extracts show that the hydroethanolic oak bark obtained using MAE has the highest absolute value of the TPC (347.74 mg/g). In comparison with the extracts obtained using UAE, the bark extracts obtained using MAE showed a significantly higher TPC. The greatest antioxidant and antibacterial activity were also recorded for the tested extracts. For gram-positive bacteria, the MBC values ranged from 0.3 (S. aureus) to 5 mg/mL and the oak bark extract obtained using MAE showed good activity against C. krusei (MIC—2.5 mg/mL). Among the assayed enzyme inhibitory activities, the extracts showed a significant antidiabetic effect in vitro with the highest activity corresponding to an IC50 of 3.88 µg/mL. The older oak bark represents a potential source of compounds with antibacterial, antioxidant or antidiabetic activity, which can be exploited through the biorefining processes.
Pericoronitis is characterized by inflammation of the tissues surrounding an erupting tooth and occurs most commonly in lower wisdom teeth. The extent of inflammatory phenomena can significantly affect the patient’s quality of life because of the pain, bleeding, and discomfort caused by it. The treatment of pericoronitis is carried out locally by irrigation and debridement in the early stages, but also generally by antibiotic therapy, when purulent secretion is present under the operculum and in the periodontal area. This study aims to evaluate the effect of beech bark extract (BBE) in the treatment of pericoronitis of the lower third molar. Parameters evaluated were pain, trismus, and bleeding index in a clinic study. Four groups of 20 patients were evaluated and grouped according to the irrigation solution used during the treatment: chlorhexidine 0.2% (CHX), BBE and chlorhexidine mixture solution 0.2% (1:1), and BBE and saline solution (control). The evaluation was carried out before and after the irrigation. Following the assessment of pain and trismus, a significant decrease in pain and a significant increase in mouth opening after 3 days was observed in patients treated with BBE, CHX, and BBE + CHX (p = 0.00). In the case of control patients, no significant decrease in pain (p = 0.83) was observed after 3 days, nor was there a significant increase in the opening of the oral cavity (p = 0.157). The evaluation of the inflammation index showed a significant decrease in gingival bleeding after 3 days for most patients treated with tested solutions (p < 0.05). It was concluded that irrigation with BBE was more effective in reducing pain, trismus, and bleeding compared to the other solutions (control, CHX, BBE + CHX), and this natural extract can be a choice in case of pericoronitis debut.
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