Flora of Turkey and the East Aegean Islands.

It would be desirable to establish and standardize methods that can measure the total antioxidant capacity level directly from vegetable extracts containing phenolics. Antioxidant capacity assays may be broadly classified as electron transfer (ET)- and hydrogen atom transfer (HAT)-based assays. The majority of HAT assays are kinetics-based, and involve a competitive reaction scheme in which antioxidant and substrate compete for peroxyl radicals thermally generated through the decomposition of azo compounds. ET-based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes colour when reduced. ET assays include the ABTS/TEAC, CUPRAC, DPPH, Folin-Ciocalteu and FRAP methods, each using different chromogenic redox reagents with different standard potentials. This review intends to offer a critical evaluation of existing antioxidant assays applied to phenolics, and reports the development by our research group of a simple and low-cost antioxidant capacity assay for dietary polyphenols, vitamins C and E, and human serum antioxidants, utilizing the copper(II)-neocuproine reagent as the chromogenic oxidizing agent, which we haved named the CUPRAC (cupric ion reducing antioxidant capacity) method. This method offers distinct advantages over other ET-based assays, namely the selection of working pH at physiological pH (as opposed to the Folin and FRAP methods, which work at alkaline and acidic pHs, respectively), applicability to both hydrophilic and lipophilic antioxidants (unlike Folin and DPPH), completion of the redox reactions for most common flavonoids (unlike FRAP), selective oxidation of antioxidant compounds without affecting sugars and citric acid commonly contained in foodstuffs and the capability to assay -SH bearing antioxidants (unlike FRAP). Other similar ET-based antioxidant assays that we have developed or modified for phenolics are the Fe(III)- and Ce(IV)-reducing capacity methods.

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Comparative Evaluation of Various Total Antioxidant Capacity Assays Applied to Phenolic Compounds with the CUPRAC Assay

Essential oil composition, antimicrobial and antioxidant activities of Satureja cuneifolia Ten.

Chemical composition, antioxidant and antimicrobial properties of the essential oils of three Salvia species from Turkish flora.

Thyme (Thymus vulgaris L., Lamiaceae) is a subshrub from the Lamiaceae family with plants that are rich in essential oils and antioxidative phenolic substances. Twelve accessions originating from southern France and the variety ʼDeutscher Winterʼ were grown in an experimental field in eastern Austria. Leaf samples from these plants as well as from a commercial thyme rich in thymol were analyzed for their essential oil and the antioxidative potential in various extracts. The assays for antioxidative activity were the total phenolics according to the Folin−Ciocalteu method, DPPH decoloration, and Fe3+ reduction (FRAP). Both extraction techniques used, in the water bath at 40 °C and in the ultrasonic bath at room temperature, proved to be efficient. The best results were obtained with 60% ethanol as extractant. In the comparison of the different accessions the less active and the most active of these extracts differed by factors of 2.1 and 2.6 in the total phenolics and FRAP assay, respectively, and by facto...

Antioxidative Properties of Thymus vulgaris Leaves: Comparison of Different Extracts and Essential Oil Chemotypes

Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia verticillata (L.) subsp. verticillata and S. verticillata (L.) subsp. amasiaca (Freyn & Bornm.) Bornm

The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten

Context: Origanum (Lamiaceae) has been used in food and pharmaceutical industries.Objective: Isolation and identification of bioactive compounds from Origanum rotundifolium Boiss. and investigation of their antiproliferative and antioxidant activities.Materials and methods: The aerial part of O. rotundifolium was dried and powdered (1.0 kg ±2.0 g) then extracted with hexane, ethyl acetate, methanol and water. Solvent (3 × 1 L) was used for each extraction for a week at room temperature. The aqueous extract was partitioned with ethyl acetate (3 × 1 L) to yield the water/EtOAc extract subjected to chromatography to isolate the active compounds. The structures of isolated compounds were elucidated by 1 D, 2 D NMR and LC-TOF/MS.Results: Apigenin (1), ferulic acid (2), vitexin (3), caprolactam (4), rosmarinic acid (5), and globoidnan A (6) were isolated and identified. Globoidnan A (6), vitexin (3), and rosmarinic acid (5) revealed the excellent DPPH• scavenging effect with IC50 values of 22.4, 31.4, 4...

https://tandfonline.com/doi/pdf/10.1080/13880209.2017.1310906

Bioassay-guided isolation, identification of compounds from Origanum rotundifolium and investigation of their antiproliferative and antioxidant activities.

Tradescantia fluminensis Vell. (Commelinaceae) has been recorded as a new naturalised alien species for the flora of Turkey from NE Anatolia. Its description, detailed leaf and stem anatomical properties, measurements, and photographs are presented in this paper. It was observed that the stems have a primary structure, the central cylinder comprises 2 concentric rings of closed collateral vascular bundles, and the leaves are bifacial and hypostomatic, with tetracytic stomata cells. In addition, it was determined that the thickness of the leaf lamina is 326 ± 4.79 µm and average of stomatal length and stomatal index in the abaxial surface of the leaf is 51.70 ± 0.33 µm and 12.54 ± 1.33, respectively.

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Contributions to the Leaf and Stem Anatomy of Tradescantia fluminensis: an Alien Species New to the Flora of Turkey

Rhus chinensis Mill. (Anacardiaceae) has been reported as a new record for the flora of Turkey. Detailed morphological description and leaf anatomical properties are provided. Capitate glandular and nonglandular trichomes, and also epicuticle hairs have been observed in the leaf surfaces of R. chinensis . Fruit micromorphology and chromosome number of this species have also been evaluated. Bangladesh J. Plant Taxon. 25 (1): 71-78, 2018 (June)

/pdf/morphological-and-anatomical-studies-of-the-newly-recorded-tx5i97b460.pdf

Özgür Eminağaoğlu

Papers

Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia verticillata (L.) subsp. verticillata and S. verticillata (L.) subsp. amasiaca (Freyn & Bornm.) Bornm

The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten

Bioassay-guided isolation, identification of compounds from Origanum rotundifolium and investigation of their antiproliferative and antioxidant activities.

Contributions to the Leaf and Stem Anatomy of Tradescantia fluminensis: an Alien Species New to the Flora of Turkey

Morphological and anatomical studies of the newly recorded Rhus chinensis Mill. (Anacardiaceae) from Turkey