İş Sağlığı ve Güvenliği Bölümü

Anti-radical Flavonoids from Teucrium chamaedrys L. subsp. sinuatum (Celak.) Rech. F.

2016-03-19T00:00:00Z

Anti-radical Flavonoids from Teucrium chamaedrys L. subsp. sinuatum (Celak.) Rech. F. Geçibesler, İbrahim Halil Teucrium species are aromatic plants with interesting pharmacological and biological properties. A phytochemical investigation of the aerial parts Teucrium chamaedrys L. subsp. sinuatum led to the isolation of a flavone named 5,6,3'-trihydroxy-7,4'-dimethoxyflavone (1) and a flavone glycoside, luteolin-7-O-glucoside (2) from the polar extract. Both compounds were isolated and identified for the first time in Teucrium chamaedrys L. subsp. sinuatum. In vitro anti-radical activity of both the compounds was assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Compound 1 triggered a significant decrease in amount of DPPH radicals with EC50 value of 43.41± 2.17 μg/ml.

Antioxidant Activity and Phenolic Content of Different Parts of Chrysophthalmum montanum (DC.) Boiss.

2016-03-19T00:00:00Z

Antioxidant Activity and Phenolic Content of Different Parts of Chrysophthalmum montanum (DC.) Boiss. Geçibesler, İbrahim Halil Natural antioxidants with plant-origin have been used for years in the food, medical and cosmetics applications as well as folk medicine due to their effective ingredients against various pathogenic cases. For these reason, this study reports the antioxidant activities of methanolic extracts from flower (CF), stem (CS), root (CR) and leaf (CL) of Chrysophthalmum montanum from Turkey and determination their antioxidant contents in terms of total phenolic and flavonoid. The antioxidative activities were measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test, 2,2'-azinobis[3-ethylbenzthiazoline-6-sulphonic acid (ABTS) assay, superoxide anion scavenging activity (SASA) assay, lipid peroxidation test with ferric thiocyanate (FTC) method, reducing power activity (RPA) assay and metal-ion chelating power (MCP). The in vitro experiments revealed that CF extract could decrease the production of ROS and free radicals in media as much as positive standards. The findings mean that title plant is highly important in antioxidant activities. It was suggested that phenolic and flavonoid components might contribute its antioxidant activities against free radicals. This study will bring an innovation for further studies on the antioxidant properties of C. montanum and especially the CF extract can be considered as a source of potential antioxidants and it would promote the reasonable usage of this plant in food technology and processing as well as for medical use.

Comparative assessment of phenolic and flavonoid contents of some Citrus peels and their antioxidant capacity

2016-05-23T00:00:00Z

Comparative assessment of phenolic and flavonoid contents of some Citrus peels and their antioxidant capacity Geçibesler, İbrahim Halil Aim of the study: To determine the richest phenolic and flavonoid content of fresh, dried and frozen of some highly economic citrus peels mandarin (Citrus reticulata), orange (Citrus sinensis), lemon (Citrus limon) and grapefruit (Citrus paradisi) as well as antioxidant capacities. Material and Methods: Ultrasound assisted extraction was used to recover extracts from fresh, frozen and dried Citrus peels. The antioxidant activity studies were carried out by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals, superoxide anion radicals, reducing power, metal-ion chelating and total antioxidant activity by ferric thiocyanate methods. The total phenolic content (Folin–Ciocalteu assay) and flavonoid content were also determined by UV-VIS spectrometer. Results: Fresh, frozen and dried citrus peels showed good antioxidant activity in all the biological antioxidant activity experiments (p<0.05). The total phenolic content ranged from 67.36±3.09 to 227.21±1.78 mg of gallic acid equivalents (GAE)/100 g dry extract. Interestingly, among citrus samples, dried lemon and grapefruit had the highest total phenolic contents of 168.34±4.03 and 227.21±1.78 mg (GAE)/100 g dry extract, respectively. At the concentration of 75 μg/ml, dried lemon extract exhibited the highest superoxide anion radical scavenging and reducing power activities with scavenging percentage of 93.45 and 88.81 %, respectively, however, at same concentration, the superoxide anion radical scavenging and reducing power activities of dried orange extract were 68.54 and 71.59%, respectively . These results showed that the amounts of phenolics compounds were in accordance with higher effectiveness in performed antioxidant activity tests. Acknowledgements: The author thanks for financial support the projects of Scientific Research Project Department of Bingol University (Projects No: BAP-21-217-2014 and BAP-21-322-2015).

Contact toxicity of Stachys byzantina C. Koch against Sitophilus granarius

2016-05-23T00:00:00Z

Contact toxicity of Stachys byzantina C. Koch against Sitophilus granarius Geçibesler, İbrahim Halil Aim of the study: To figure out the contact toxicity of organic extract from the aerial part and leaf of Stachys byzantina in growing Turkey. Material and Methods: Air dried and powdered aerial parts and leafs of the Stachys byzantina were macerated with methanol:dichloromethane (1:1; v/v). Each extract was concentrated under reduced pressure to give solvent free residue. The obtained extracts were diluted with acetone to obtain 10% (w/w) stock solution. 1 mL of each plant extract was applied to every insect with a microapplicator and acetone was used as the blank in the control. The insects were incubated at 27 ºC in a dark climatic chamber and the mortality was recorded every 24 h for 3 days. The whole experiment was repeated three different times. Results: The aerial part (50.00±1.01%) and leaf (39.86±1.05%) extracts of Stachys byzantina showed contact toxicity against S. granarius. When compared with blank control (acetone) 00.00 ± 0.00% after 24, 48 and 72 h, the aerial part extract showed significantly higher activity (p<0.05). The results obtained suggest that the aerial part extract could be considered as a potential source of natural insecticides. Acknowledgements: I.H Geçibesler would like to express his sincere thanks to Prof. Dr. İbrahim Demirtaş, Department of Chemistry, Science Faculty, Çankırı Karatekin University for his supervisor. Author also thanks Assist. Prof. Dr. Omer Cem Karakoç Department of Crop and Animal Protection Yapraklı Vocational School, Çankırı Karatekin University for contact toxicity studies.