The object of the present study was to investigate the antioxidant, antimicrobial activity and phenolic compounds of fruit and seeds of Diospyros lotus L. The fruits consumed by humans as nutrients were harvested from the plants that grow naturally in the province of Trabzon-Akçaabat, Eastern Black Sea Region of Turkey. The antioxidant activities of fruit and seeds of Diospyros lotus were determined by using four methods (% DPPH radical scavenging activity, FRAP antioxidant power determination, CUPRAC reducing antioxidant activity and total phenolic content (TPC) in five different proportion of methanol-water extracts. All extracts of fruit and seeds of D. lotus analyzed through whole antioxidant analysis methods showed significant antioxidant activity. In addition, antimicrobial activity of fruit and seeds extracted with DMSO was determined against seven standard bacteria and three multi-drug resistance clinical strains. Although fruit extracts did not have the antimicrobial activity against bacteria, seeds showed antimicrobial effect to both standard strains (Gram-negative and Gram-positive) and antibiotic resistance clinical isolates (Klebsiella pneumoniae carrying blaKPC, Acinetobacter baumannii, harboring blaOXA-23 gene and resistance to colistin, and multi-drug resistant Pseudomonas aeruginosa). MICs’ value of plant seed extracts for standard strains was 0.75-25 mg/mL and antibiotic resistant clinical bacteria were 12.5 and 25 mg/mL. Additionally, phenolic compounds in methanol extracts of fruit and seeds were also determined in by HPLC using 19 standards. Gallic acid and chrysin phenolic compounds were the major phenolic compounds in fruit and seeds, respectively.

In this study, the physicochemical properties and antioxidant activities of the commercially produced 15 pomegranate sour samples and one control sample were determined and their compliance with the TS 12720 (traditional sour pomegranate concentrate standard) was evaluated. Antioxidant activity values of pomegranate sours extracts were determined using 6 different methods. The samples had strong antioxidant capacity, except for N10 and N15. In addition, glucose, fructose, sucrose, HMF and acidity measurements of the same samples did not show compatibility with TS 12720. The pH values of the samples of N7, N8, N10, N11, N14 and N15 were not in accordance with the standard values (2.4-4.0) The titratable acidity values measured in samples of N1, N3, N4, N6, N10, N13, N15 were below the value (>6.0% (m/m)) in the standard. While the brix values of the samples were measured between 59.20-75.70, the brix values of the N12, N13 and N14 samples were determined below the standard brix value (>68%). The highest HMF value of the samples were determined as 8117.66. According to TSE 12720, the HMF content should be not exceed 50 mg/kg. However, the HMF values of the samples were detected above the maximum limit value except for N8 and N16.

Algae contain a large amount of biological active compounds functioning as antioxidant, antimicrobial and anti-tumour. In the present research, antioxidant activity of freshwater alga Microspora sp. (Chlorophyta) extract prepared in different solvents (methanol, acetonitrile, ethanol, acetone and ethyl acetate) was determined with three different methods; 2,2-diphenyl-1-picrylhydrazyl (DPPH•), Iron (III) Reduction / Antioxidant Power (FRAP) Assay and Copper (II) Reductive Antioxidant Activity (CUPRAC). The alga samples collected from the high mountain lake (2733 meters above sea level) localized in Gümüşhane province of Turkey. The algal extracts prepared in different solvents showed antioxidant activity. The values of DPPH• varied from 8.97% (in acetonitrile extract) to 31.15% (in methanol extract). As in the DPPH• method, the lowest and highest values in the FRAP method were measured based on μM TEAC (Trolox Equivalent Antioxidant Capacity) in methanol and acetonitrile extracts as 60.303 μM and 359.394 μM respectively. While the lowest value of CUPRAC test was determined in acetonitrile extract (0.041 μM TEAC ) as in the other tests, highest value was measured in ethanol extract (0.101 μM TEAC ) as different from the others. While the values of highest antioxidant activity in both DPPH• and FRAP methods was measured in the methanol solvent, it was determined in the ethanol solvent for CUPRAC. Keywords: Algae; Microspora sp.; Antioxidant; DPPH•; FRAP; CUPRAC DOI: 10.17350/HJSE19030000129 Full Text:

In the study, the phenolic components and antioxidant activities of edible and nonedible parts of tuber of Arum italicum plant were carried out to determine in methanolic and water extracts. In addition, the antioxidant potential of these parts of the plant was associated with their phenolic composition. Total phenolic content, FRAP, CUPRAC and DPPH tests as radical scavenging activity were performed to determine the antioxidant activity of the plant. The phenolic profiles in the two parts of the tuber were determined in the prepared methanolic extracts by RP–HPLC–UV and LC–MS/MS. The highest values of the total phenolic content, FRAP, CUPRAC and % DPPH were measured in methanolic extracts of nonedible parts of the tuber as 164 µg GAE / mL, 878 TEAC (µM), 0.064 TEAC (µM) and 19.41, respectively. Phenolic profiles of methanolic extracts include rutin, epicatechin, caffeic acid, ferulic acid, p-coumaric acid and vanillin as major components. According to these results, it can be concluded that the nonedible tuber part can be consumed as food.

In this study, it was aimed to determine the physical, chemical and antioxidant properties of pomegranate sauces sold in the market in Turkey. A total of 18 pomegranate sauces were studied; 17 of which were purchased from the market, and one of them was produced in a rotary evaporator in the laboratory. For each sample, analysis of antioxidant activity, titratable acidity, brix, hydroxymethyl furfural, pH, color analysis, and sugar analyzes were performed. Antioxidant activity values were analyzed using 6 different methods (DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging activity, ferric reducing antioxidant power (FRAP), ABTS●+ radical scavenging capacity, total antioxidant capacity assay (TAC), the total phenolic content (TPC) and total flavonoid content (TFC) methods). The lowest and highest values were determined for methods of DPPH (5.23- 2822.69 mg AA/kg), FRAP (57.94 - 2380.94 mg FeSO4/kg), TAC (660.47 - 3690.83 mg AA/kg), TFC (23.06 - 11680.71 mg QEE/kg), TPC (123.54 -9566.95 mg GAE/kg). Brix, pH and % titration acidity values varied between 70.00 - 76.70%, 1.66 -2.88, 2.65 -7.58%, respectively. In addition, HMF values were measured below the limit values in most of the samples, while these values were found to be high in some of the samples. The highest and lowest HMF values were measured between 4.58 -103.68 mg/kg, respectively. Many factors such as raw materials, additives, applied heat treatments, production processes and storage conditions are effective on produced pomegranate sauces. If the production conditions are regulated in accordance with the standards, the HMF values in pomegranate sauce will be below the limit.