Akşit, Hüseyin; Şimşek, Samed

In this study, the antioxidant capacity of the hydromethanolic extract obtained from the floral parts of Verbascum sinuatum was evaluated, and its total phenolic, flavonoid, verbascoside, and sugar contents were determined. The antioxidant capacity of the extract was evaluated using DPPH, ABTS, and FRAP assays. Total phenolic and flavonoid contents were measured spectrophotometrically, while the verbascoside and sugar contents of the extract were quantified by the HPLC-UV and HPLC-RID methods, respectively. According to the results, the DPPH radical scavenging activity of the extract was found to be IC50= 30.70±1.76 µg/mL, and the ABTS value was IC50= 17.31±0.65 µg/mL. The FRAP activity was determined as 63.94±0.98 mg TE/g extract. The total phenolic content was measured as 45.23 0.77 mg GAE/g, and the total flavonoid content as 6.31±0.50 mg QE/g. According to the HPLC-UV analysis, the verbascoside content of the extract was found to be 9.72±0.85 mg/g. Additionally, the results demonstrated that fructose (190.39 mg/g) was the most abundant sugar in the floral extract of V. sinuatum, followed by glucose (132.91 mg/g) and a relatively small amount of sucrose (7.21 mg/g). As a result, the hydromethanolic extract of V. sinuatum floral parts exhibited a considerable level of antioxidant activity, contained significant amounts of phenolic compounds, particularly verbascoside, and was rich in hexose sugars, especially fructose and glucose. These findings suggest that this plant may be considered a promising natural source of antioxidants and bioactive compounds.

Baltaci, Cemalettin; Akşit, Zeynep; Şidim, Muhammed

Sage is used as an aroma and spice in foods around the world. With its strong and even bitter taste, sage has been traditionally used as an effective solution to many health problems for centuries. It is a rich plant with many bioactive compounds. In this study, instant tea production was performed from the dried samples of the sage plant (Salvia rosifolia Sm.) using two drying methods; freeze-drying and spray-drying. The sensorial, physicochemical, antioxidant and antimicrobial properties of the products obtained by both methods were analyzed. Color values, solubility in water, moisture analysis (21.3% spray-dried; 4.0% freeze-dried), free radical scavenging activity (DPPH), Trolox Equivalent Antioxidant Capacity (TEAC), Ferric reducing/antioxidant power assay (FRAP), aroma analysis, protein analysis (5.5% spray-dried; 5.7% freeze-dried), ash, mineral, antimicrobial and sensory analyses were performed. Significant differences were found between two soluble tea obtained by the spray-drying and the freeze-drying methods. In general, the antioxidant capacities are higher in freze-dried samples. All of the 61 aroma components were detected in freeze dried samples while only 18 of them were detected in spray dried samples. In addition to their differencies; plenty of bioactive components, easy to use, ready to drink herbal tea have been produced with both techniques.

Yüksek, Haydar; Kardaş, Faruk; Ocak, Zafer

In this study, seven novel di-{2-ethoxy-6-[(3-substitue-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)azomethine]phenyl} terephtalates (4a-g) were synthesized from the rections of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2a-g) with di-(2-formyl-6-ethoxyphenyl) terephtalate (3). The compounds 4a-g were characterized using by IR, 1H-NMR, 13C-NMR and UV spectral data. In addition, 4 type compounds were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropanol, tert-butanol, dimethyl ketone, N,N-dimethylformamide and the half-neutralization potential values and the corresponding pKa values were determined for all cases.

Ozdokur, Kemal Volkan; Ertaş, Fatma Nil; Kırlangıç, İrem Aydın

Parkinson's disease (PD) is a degenerative disorder of the central nervous system. The motor symptoms of PD disease result from the death of dopamine-generating cells in a region of the mid brain and the dopamine precursor levodopa (L-Dopa) is used for the treatment. Carbidopa (Car) is administered in association with L-Dopa in pharmaceutical formulation as an inhibitor on the decarboxylase activity. Thus, their simultaneous determination is of great importance because of their co-existence in pharmaceutical preparations. Present study deals with a simple method development for simultaneous voltammetric determination of L-Dopa and Car at a pencil graphite electrode (PGE) via monitoring the reduction peak of L-Dopa and the second oxidation peak of Car. The sensitivity of the method was found comparable to other methods depending on the sophisticated electrode modifications and the limits of detection were calculated as sub micromolar levels.

Yüksek, Haydar; Manap, Sevda; Ozdemir, Gul; Kardaş, Faruk

In this study, to determine the pKa values of 2-ethoxy-6-(3-substitue-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl-azomethine)-phenyl benzoates (1-9) were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethylformamide (DMF), and graphs were drawn for all cases. In addition, the effects of solvents and molecular structure upon acidity compounds 1-9 were also determined and discussed. The half-neutralization potential values and the corresponding pKa values were determined by half neutralization method.