Seasonal variation of total phenolic, antioxidant activity and minerals in fresh tea shoots (Camellia sinensis var. sinensis).

Seasonal variation of total phenolics, antioxidant activity and minerals in fresh tea shoots, consisting of one apical bud and two adjoining leaves sampled from Muradiye, Tuglali, Gundogdu, Enstitu 9, Hamzabey, Hayrat and Pazar 20 clones grown in Eastern Black Sea region in Turkey was investigated during three harvest season (May, July and September) in both 2006 and 2007 years. The total phenolics of all clones were lower in cool months of May in both years (average 33.00-90.27 mg GAE/g dry weight basis). Thereafter, the levels of total phenolics increased throughout the warmer months from July to September. Antioxidant activity determined by beta-carotene bleaching assay showed similar trends which increased from 1st harvest (May) to 3rd harvest (September). All clones showed nearly 100% antioxidant activity at 2nd and 3rd harvest season which higher than standard synthetic antioxidant BHA (butylated hydroxyanisole). However, seasonal variation of minerals (N, P, K, Ca, Mg, Na, Fe, Cu, Mn, Zn) showed different results according to clones used. These results seem to suggest that the harvest time is crucial to determining the antioxidant potential of fresh tea shoots.

Antioxidant properties and total phenolic content of eight Salvia species from Turkey.

Methanolic extracts of eight Salvia species, namely S. aethiopis, S. candidissima, S. limbata, S. microstegia, S. nemorosa, S. pachystachys, S. verticillata, and S. virgata, sampled from Eastern Anatolia in Turkey, were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid. Total phenolic content of the extracts of Salvia species were performed Folin-Ciocalteu reagent and gallic acid used as standard. A wide variation has been observed among species in terms of antioxidant activity and total phenolic content. In both DPPH and beta-carotene system, the most active plant was Salvia verticillata with a value of IC50=18.3 microg/ml and 75.8%, respectively. This species also has the highest total phenolic content (167.1 mgGAE/g DW). The total amount of phenolics was between 50.3 to 167.1 mgGAE/g DW among species. A positive linear correlation was observed between total phenolic content and antioxidant activity of the extracts. The results suggest that the extract of Salvia species, notably Salvia verticillata with the highest antioxidant activity, can be used as natural antioxidants in the food industry.

Total phenolic content, antioxidant and antimicrobial activities of some medicinal plants.

Crude extracts from Inula aucherana, Fumaria officinalis, Crocus sativus, Vicum album, Tribulus terestris, Polygonatum multiflorum, Alkanna tinctoria and Taraxacum officinale were screened for their in vitro antioxidant and antimicrobial properties. Total phenolic content of extracts from these plants were also determined. beta-carotene bleaching assay and Folin-Ciocalteu reagent were used to determine total antioxidant activity and total phenols of plant extracts. Antimicrobial activity was determined by using disk diffusion assay. Antioxidant activity and total phenolic content varied among plants used and Viscum album and Crocus sativus had the highest antioxidant (82.23%) and total phenolic content (42.29 mgGAE/g DW), respectively. The methanol extracts from Vicum album and Alkanna tinctoria showed antimicrobial activity against 9 out of 32 microorganisms, however extract from Inula aucherana showed antimicrobial activity against 15 out of 32 microorganisms. The results provided evidence that the studied plant might indeed be potential sources of natural antioxidant and antimicrobial agents.

Phytochemical characterization of several hawthorn (Crataegus spp.) species sampled from the Eastern Mediterranean region of Turkey.

BACKGROUND: We evaluated the total phenolic content, antioxidant capacity as well as antioxidant activity of five Crataegus species (A1, A2, Y1, Y2, Y4 accessions of Crataegus aronia var. aronia; B2, B3, B5, B6, B7, B9, Y5 accessions of C. aronia var. dentata; B10 accession of C. aronia var. minuta; Y3 accession of Crataegus orientalis var. orientalis and A3 accession of Crataegus monogyna subsp. azarella). MATERIALS AND METHODS: Antioxidant activity and total phenolic content of fruits were determined by ß-carotene bleaching and Folin-Ciocalteu assays. Antioxidant capacity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. RESULTS: C. monogyna subsp. azarella had the highest total phenol, antioxidant activity and antioxidant capacity of 55.2 mg gallic acid equivalents (GAE)/g dry weight (DW), 81.9% and 31.2%, respectively. C. aronia var. aronia was found to have the lowest total phenolic content (35.7 mg GAE/g DW). The antioxidant activities of fruit extracts increased in the order of C. orientalis var. orientalis < C. aronia var. minuta < C. aronia var. dentata < C. aronia var. aronia < C. monogyna subsp. azarella according to ß-carotene/linoleic acid assay. In recent years, C. aronia var. dentata has gained importance as a commercial species in this region. B3 and B7 accessions had fruit weight more than 14 g, and considerable total phenol content, antioxidant activity and antioxidant capacity. CONCLUSION: This investigation shows the potential value of hawthorn fruit species as a good source of natural antioxidants and that consumption of hawthorn fruit or its products may contribute substantial amounts of antioxidants to the diet.

Antioxidant, Antimicrobial Activity and Total Phenolic Content within the Aerial Parts of Artemisia absinthum, Artemisia santonicum and Saponaria officinalis.

Three native Turkish medicinal and aromatic plants (Artemisia absinthum, Artemisia santonicum and Saponaria officinalis) were investigated to analyze their antioxidant activity, total phenolic content and antimicrobial activity. Their total antioxidant activity was determined by using a ß-carotene bleaching assay and their antimicrobial activity was determined by utilizing an agar disc diffusion assay. Methanol extracts of the three species analyzed showed high antioxidant activity and among them Artemisia absinthum possessed the highest quantity (71.78%). The total phenolic content (Folin-Ciocalteu assay) was shown to be between 6.57 µgGAE/mg dry weight basis (Saponaria officinalis) and 8.86 µgGAE/mg dry weight basis (Artemisia absinthum). There was a positive correlation (R = 0.819) between the total phenolic content and the antioxidant activity measured in the plant samples. The aqueous and methanol extracts of the aerial parts of the species showed antibacterial activities against a number of microorganisms. The methanol extracts were found to inhibit the growth of microorganisms more than the aqueous extracts. These findings suggest that the methanol extracts of the plants tested contain compounds with antimicrobial properties. These exhibited properties propose that such plant extracts can possibly be used as natural preservatives in the food and pharmaceutical industries.

Antioxidant activities and fatty acid composition of wild grown myrtle (Myrtus communis L.) fruits.

The fruits of eight myrtles, Myrtus communis L. accessions from the Mediterranean region of Turkey were evaluated for their antioxidant activities and fatty acid contents. The antioxidant activities of the fruit extracts were determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and beta-carotene-linoleic acid assays. The fatty acid contents of fruits were determined by using gas chromatography. The methanol extracts of fruits exhibited a high level of free radical scavenging activity. There was a wide range (74.51-91.65%) of antioxidant activity among the accessions in the beta-carotene-linoleic acid assay. The amount of total phenolics (TP) was determined to be between 44.41-74.44 mug Gallic acid equivalent (GAE)/mg, on a dry weight basis. Oleic acid was the dominant fatty acid (67.07%), followed by palmitic (10.24%), and stearic acid (8.19%), respectively. These results suggest the future utilization of myrtle fruit extracts as food additives or in chemoprevention studies.

Phenolic and antioxidant diversity among persimmon (Diospyrus kaki L.) genotypes in Turkey.

The amount of research on the healthy benefits of fruits has increased in recent years. The objective of the present study is to determine the antioxidant activity and total phenolic content of 18 selected persimmon genotypes. The genotypes were established in a collection parcel at the Black Sea Agricultural Research Institute, Samsun, Turkey. The beta-carotene bleaching method was used to determine antioxidant activity and the Folin-Ciocalteau colorimetric method to determine total phenolics in persimmon fruits. The total phenolic content in fruits, estimated as gallic acid equivalents, ranged from 15.7 mg/g dry weight for 08 TH 12 to 42.3 mg/g gallic acid equivalent for the 08 TH 10 genotype. The highest antioxidant activity was observed in 08 TH 10 as 91.6%, while the lowest was in 14 TH 01 (51.7%), respectively. The antioxidant activities of butylated hydroxyanisole and butylated hydroxytoluene were 93.4% and 91.8%, respectively. A low correlation (R = 0.711) was obtained between total phenolic content and antioxidant activity among genotypes. The results indicate that antioxidant activity in persimmon fruits is strongly affected by genotype.

Antioxidant Properties and Total Phenolic Content of Eight Salvia Species from Turkey

Methanolic extracts of eight Salvia species, namely S. aethiopis, S. candidissima, S. limbata, S. microstegia, S. nemorosa, S. pachystachys, S. verticillata, and S. virgata, sampled from Eastern Anatolia in Turkey, were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical scavenging and b-carotene/linoleic acid. Total phenolic content of the extracts of Salvia species were performed Folin-Ciocalteu reagent and gallic acid used as standard. A wide variation has been observed among species in terms of antioxidant activity and total phenolic content. In both DPPH and b-carotene system, the most active plant was Salvia verticillata with a value of IC50=18.3 μg/ml and 75.8 percent, respectively. This specie also has the highest total phenolic content (167.1 mgGAE/g DW). The total amount of phenolics was between 50.3 to 167.1 mg GAE/g DW among species. A positive linear correlation was observed between total phenolic content and antioxidant activity of the extracts. The results suggest that the extract of Salvia species, notably Salvia verticillata with the highest antioxidant activity, can be used as natural antioxidants in the food industry.