Investigation of novel plant-based agents might provide alternative antibiotics and thus fight antibiotic resistance. Here, we measured the ability of fruit and leaf extracts of Sorbus aucuparia (Sauc) and endemic Sorbus caucasica var. yaltirikii (Scau) to inhibit nonreplicative (Klenow Fragment-KF and Bacillus Large Fragment-BLF) and replicative (DnaE and PolC) bacterial DNA polymerases along with their antimicrobial, DPPH free radical scavenging activity (RSA), and chemical contents by total phenolic content and HPLC-DAD analysis. We found that leaf extracts had nearly 10-fold higher RSA and 5-fold greater TPC than the corresponding fruit extracts. All extracts had large amounts of chlorogenic acid (CGA) and rutin, while fruit extracts had large amounts of quercetin. Hydrolysis of fruit extracts revealed mainly caffeic acid from CGA (caffeoylquinic acid) and quercetin from rutin (quercetin-3-O-rutinoside), as well as CGA and derivatives of CGA and p-coumaric acid. Plant extracts of Sorbus species showed antimicrobial activity against Gram-negative microorganisms. Scau leaf extracts exhibited strong inhibition of KF activity. Sauc and Scau leaf extracts also strongly inhibited two replicative DNA polymerases. Thus, these species can be considered a potential source of novel antimicrobial agents specific for Gram-negative bacteria.

Objectives: This in vitro study assessed the effect of different lightcuring units on the elution of monomers from bulk fill composites with different thicknesses. Methods: Five bulk fill composites (Filtek Bulk Fill Flowable, SonicFill 2, SDR, and Venus Bulk Fill) and one conventional composite (Filtek Z250) were selected for the study. The cylindrical specimens in thickness of 2 mm or 4 mm were prepared and photopolymerized for 20 s with a light-emitting diode (VALO Cordless) or a halogen (Monitex BlueLuxer) light-curing unit. The specimens in glass vials were covered with a 75% ethanol/water solution. Ethanol/water extraction solutions were collected for high-performance liquid chromatography analysis after 24 h, 3 days, and 7 days. The data were analyzed with repeated measures and three-way ANOVA (p < 0.05). Results: The total monomer amount was significantly influenced by light-curing source used and thickness. The highest levels of Bis-GMA and Bis-EMA were eluted from Tetric N-Ceram BulkFill and Venus Bulk Fill, respectively. SonicFill 2 released the highest level of TEGDMA at 4-mm thickness. The highest levels of UDMA release, from 4-mm-thick Filtek Bulk Fill Flowable, were attained using the halogen unit. Conclusions: Light-curing sources affected the number of monomers released by materials. The amount of eluted monomers declined over time. The increased ratio of released monomers to increased thickness is material dependent. The number of residual monomers is highly associated with the resin ratio and crosslinking network of the composites.

The goal of this study was to examine the effect of thermal cycling on the amount of monomer released from bulk fill composites. Five bulk fill composite resins were used in the study. Extraction solutions were obtained at the end of the time/thermal cycle periods: 0-1 day/0-1,500, 1-3 days/1,500-4,500 and 3-7 days/4,500-10,000. The monomers in the extractions samples taken at each time point were measured on an HPLC instrument. The obtained data were analyzed by repeated measures of variance analysis and tukey multiple comparison tests (p<0.05). The thermocycling increased the amount of monomer released from all composites at 0-1 day (p<0.05). At 0-1 and 1-3 days, Venus Bulk Fill and Filtek Bulk Fill composite resins were more affected. Polymer networks with high molecular weight monomers such as Bis-GMA and UDMA can be less affected by thermal changes compared to polymers with low molecular weight monomers.

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