Emine Akyüz Turumtay

Grayanotoxin-III Detection and Antioxidant Activity of Mad Honey

“Mad honey” is a complex mixture of numerous chemicals produced by honeybees from Rhododendron flowers. Consumption of mad honey leads to diarrhea, perspiration, dizziness, changes in consciousness, syncope, diplopia, as well as blurred vision, hypotension, and bradycardia due to the presence of grayanotoxins (GTXs). Therefore, it is important to detect the level grayanotoxins in mad honey. Besides its toxicity, mad honey also has antioxidant activity. This study was designed to determine the level of grayanotoxin-III toxin and antioxidant activity of ten different mad honey samples collected from the Black Sea region of Turkey. Liquid chromatography-tandem mass spectrometry was used for the quantitation of grayanotoxin-III. Antioxidant activity was evaluated using total phenolic contents, total ferric reducing antioxidant power, scavenging of 2,2-diphenyl-1-picrylhydrazyl and 3-(2-pyridyl)-5, 6-diphenyl-1,2,4-triazine-4’,4’’-disulfonic acid radicals. Quantities of grayanotoxin-III levels ranged from 68.754 to 0.701 µg grayanotoxin-III/g honey. Mad honey MH7 from Artvin/Hopa had the highest grayanotoxin-III level. Although there were varying levels of grayanotoxin-III, mad honey samples were outstanding in terms of antioxidant activity. MH3 had the highest antioxidant potential. Although toxicity effect comprises, a metered dose of mad honey might also be explored as a potential source in clinical trials due to high bioactivity levels.

Gram (-) microorganisms DNA polymerase inhibition, antibacterial and chemical properties of fruit and leaf extracts of Sorbus acuparia and Sorbus caucasica var. yaltirikii

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.

Comparison of phenolic profiles and antioxidant activity of three Ornithogalum L. species

Abstract Background Aboveground parts and bulbs of Ornithogalum species are consumed as food and used in traditional medicine in worldwide. Objective It is aimed to report the antioxidant capacity and phenolic compounds content of Ornithogalum sigmoideum, Ornithogalum orthophyllum and Ornithogalum oligophyllum for the first time. Materials and methods Antioxidant activity of the crude methanol extracts of the aerial parts and the bulbs of the species were determined with 1,1-diphenyl-2-picryl-hydrazyl, superoxide radical scavenging, ferrous ion-chelating effect, phosphomolybdenum-reducing antioxidant power and ferric-reducing antioxidant power assay. The ethylacetate, diethylether and water subextracts from leaf and flower were analyzed to quantify selected phenolic compounds by HPLC-UV. Results Among the six extracts, the methanol extract of the aerial parts of O. orthophyllum contained the highest amount of phenolic compounds (GAE, 11.0 mg/g extract). The aerial parts of O. orthophyllum showed higher DPPH and SOD activities than the other extracts with the SC50 values of 0.39±0.05 mg/mL and 0.44±0.08 mg/mL, respectively. Protocatechuic acid, p-hydroxybenzoic acid, vanillic acid and p-coumaric acid were the most abundant compounds at all the subextracts. Conclusion The antioxidant activity is found to be in accordance with the levels of phenolic content in the extracts.

Influence of different light-curing units on monomer elution from bulk fill composites

Abstract Objectives: This in vitro study assessed the effect of different light-curing 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, Tetric N-Ceram Bulk Fill, 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.

Plant Metabolomics and Strategies

Plant metabolomics is the study of metabolic pathways and processes to understand how plants grow and carry out functions. Over the past years, there has been a switch to a more holistic view of metabolomes. Instead of looking at individual pathways and metabolites, scientists are looking at interactions, broad pictures, and regulations. Combination of spectrometry-based technology database with (un)supervised multivariate statistical methodologies reveals a deep insight into complex metabolite patterns of plant derived samples. The ambitious goal of identifying the structure of all metabolites and hence all metabolic pathways is almost becoming within reach as MS- and NMR-based technologies and data mining approaches are rapidly evolving.