Effects of adding honey at different temperatures to linden tea on antioxidant properties and hydroxymethylfurfural formation
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a r t i c l e i n f o Available online xxxx Edited by D De Beer Halophytes, distributed from coastal regions to inland deserts have traditionally been used for medicinal and nutritional purposes. Living in sub-optimal conditions, these plants synthesize stress associated bioactive molecules, which are still remain largely unexplored. In search of natural antioxidant sources, antioxidant capacity (AC) and total phenolic content (TPC) of 100 medicinal plants (halophytes vs non-halophytes), commonly used as herbal teas, were investigated. Nutrients and phytochemical composition, especially phenolic metabolites in selected medicinal plants with higher AC were also determined. Most of the medicinal plants analysed for the first time showed considerable AC. In general, halophytes displayed higher AC and TPC than non-halophytes. High correlation indicated a major contribution of TPC in AC of these plants. Five medicinal halophytes i.e., Thespesia populneoides, Salvadora persica, Ipomoea pes-caprae, Suaeda fruticosa, and Pluchea lanceolata displayed significantly higher AC than synthetic antioxidants (BHT and BHA). Presence of bioactive phytochemicals including phenols (42.3–63.9 mg GAE g −1), flavonoids (12.3–37.1 mg QE g −1), tannins (8.7– 20 mg TAE g −1), proanthocyanidins (15.8–22.4 mg CE g −1), carotenoids (0.07–0.84 mg g −1), alkaloids (0.64– 1.1 mg g −1), and saponins (11.2–28.4 mg DAE g −1) reflected therapeutic benefits of these plants. HPLC analyses showed that the hydrolysed extracts contained chlorogenic acid, gallic acid, catechin, and quercetin as abundant phenolic metabolites which may be responsible for higher AC. These plants were also found to contain suitable amounts of proteins (8.5–17%), carbohydrates (2.6–11.4%), fibre (31.6–41.2%), and minerals (2.1–9.7%) showing their nutritional potential that has already been exploited by rural communities. The present study highlights the potential of medicinal halophytes as a source of natural antioxidants, valuable phytochemicals, and essential nutrients for pharmaceutical, nutraceutical, and chemical industries.
This study investigated some physico-chemical and biochemical characteristics of different honey types belonging to Turkish flora. Sixty-two honey samples were examined on the basis of pollen analyses, including 11 unifloral honeys (chestnut, heather, chaste tree, rhododendron, common eryngo, lavender, Jerusalem tea, astragalus, clover and acacia), two different honeydew honeys (lime and oak), and 7 different multifloral honeys. Electrical conductivity, moisture, Hunter color values, HMF, proline, diastase number, and sugar analyses of the honey samples were assessed for chemical characterization. Some phenolic components were analyzed by reverse phase high performance liquid chromatography (RP-HPLC) to determine honeys' phenolic profiles. Total phenolic compounds, total flavonoids, ferric reducing antioxidant capacity (FRAP) and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity were measured as antioxidant determinants. The study results confirm that physico-chemical and biological characteristics of honeys are closely related to their floral sources, and that dark-colored honeys such as oak, chestnut and heather, have a high therapeutic potential.
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The present study was undertaken to determine the physicochemical, biochemical, and antioxidant activities of Tunisian honey samples. All the extracted honey samples appeared to conform to the European Legislation (EC Directive 2001/110) for all parameters. Mint honey, for instance, possesses significant pH value (p < 0.05), invertase activity, water, and protein contents. In addition, this study demonstrates that the color of the Tunisian honeys is highly variable and ranges from pale yellow to dark brown. The total phenolic, flavonoid and carotenoid contents significantly vary (p < 0.05). The highest values were found in mint honey, which has a very dark color. Correlations between the analyzed parameters are statistically significant (p < 0.05). The DPPH radical scavenging activity of rosemary honey was determined as lower (p < 0.05) than the other analyzed honey samples. Yet, the highest activity was detected in mint honey. The results suggest that Tunisian honeys could be beneficially used as a functional or nutraceutical substance as they prevent or moderate oxidative stress-related diseases.
In order to find new sources of natural antioxidants, total phenolic content (TPC) and total flavonoid content (TFC) of 30 flowers in their free, esterified and insoluble-bound forms were determined. Rosa rugosa Thunb (pink) showed the highest TPC, and Osmanthus fragrans had the highest TFC. The antioxidant activities of 30 flowers were determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), ferric reducing antioxidant power (FRAP), and trolox equivalent antioxidant capacity (TEAC) assays. Rosa rugosa Thunb (purple) and Rosa rugosa Thunb (pink) had the highest DPPH (612.79 and 544.75 μmol Trolox/g DW), FRAP (273.10 and 301.14 μmol Trolox/g DW) and TEAC (1013.71 and 937.19 μmol Trolox/g DW) value. Furthermore, several phenolic compounds were detected using ultra performance liquid chromatography (UPLC) technique, and (+)-catechin, ferulic acid, isoquercitrin, and quercitrin were widely found in these flowers. The results implied that the flowers were important natural sources of bioactive components with higher antioxidant capacities for use in the food and pharmaceutical industries.
Son yillarda yurutulen bilimsel arastirmalar bitki caylarinin ve balin tasidiklari antioksidan etkili bilesenlerin bircok akut ve kronik hastaliklarin gelisme riskini azaltmaya yardimci olabilecegini gostermektedir. Ancak bitki caylarinin icerisine tatlandirici olarak bal ilave edilmesi ile antioksidan kapasitede ne gibi bir degisim olabilecegi konusu aydinliga kavusmamistir. Bu calismanin amaci, Turkiye’de satian 9 farklikarisi veya saf bitki cy onegnin total antioksidan kapasitesinin hem tek basaria hem de cm baliveya cck baliilavesinden sonra TOAK degrlerindeki olasidegsmin tespit edilmesidir. Bir fincana esegr 100 ml cydaki en yusek TOAK degri melisa, siyah cy ve beyaz cyda goumusu. Bunlarisiasila yesl cy > adacyi> ekinezya > papatya > zencefil > ilamur takip etmisir. Bitki cylarii antioksidan etkisinin hem cm hem de cck baliilavesi ile paralel olarak arttigi 7 g bal ilavesinin 3 g bala goe daha yusek etkinlik goterdig golemlenmisir. Bazibitki cylarida (melisa, adacyi ilamur, papatya, limonlu zencefil) cm baliilavesinin cck balia oranla antioksidan etkinin daha fazla yuseldig gouuken, baziarida (ekinezya) cck baliilavesinin daha etkili oldug tespit edilmisir. Sonucolarak, clisamida bitki cylaria bal ilavesinin antioksidan aktiviteyi oemli ocue artidigive gude en az 1 defa ballicy icenin vuudu serbest radikallere karsikoruyucu etki goterebileceg ve oellikle oksidatif strese bagigelisn hastalilarda destekleyici tedavi olarak kullaniabileceg dusuumektedir. Ancak bu kombinasyonunun koruyucu mekanizmasii anlasimasiicn ileri/ek clisalar gerekmektedir. Anahtar Kelimeler: Bitki cayi, cicek bali, cam bali, Total antioksidan kapasite (TOAK)
In order to find new sources of natural antioxidants, antioxidant capacities of infusions from 223 medicinal plants were systemically evaluated using ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, and their total phenolic contents (TPC) were measured by Folin-Ciocalteu method. A very weak correlation (R-2 = 0.1563) between the TEAC value and the FRAP value suggested that the components capable of scavenging free radicals could be different from those reducing oxidants in these plants. A significant correlation (R-2 = 0.7549) between TEAC value and TPC as well as a very weak correlation (R-2 = 0.1966) between FRAP value and TPC implied that phenolic compounds in these plants could be the main components contributing to scavenging free radical activities, but not be responsible for reducing oxidant abilities. Several plants possessing the high antioxidant capacities and TPC have been screened out, which could be potential rich resources of natural antioxidants, and could be developed into herbal infusion, functional food or pharmaceuticals for prevention and treatment of diseases caused by oxidative stress.
In the present study extensive HPLC-DAD, HPLC-ESI-MS and NMR analyses were undertaken in the aqueous preparations (decoctions, infusions) and tinctures of Tilia platyphyllos Scop inflorescences. The aim of this work was to examine in depth the qualitative and quantitative profile of the investigated preparations, which find until today wide applications in pharmaceutical and cosmetic industry, and to propose a validated method for their quality control. An HPLC-DAD-ESI-MS method was developed and optimised for the quantitative determination of the constituents. Marker constituents of Tiliae flos are the flavonoids, while the volatile content is also used for the quality control. However, the analyses of the non-volatile fraction gave complex chromatographic fingerprints containing simple phenolics and low molecular weight procyanidins. The use of different HPLC columns permitted a good separation of the constituents and enabled their quantitation, while HPLC-MS analyses permitted the detection of procyanidin oligomers. Overall, 31 constituents were detected and identified. Extensive preparative chromatographic investigations and 2D-NMR analyses allowed the characterisation of procyanidins as epicatechin derivatives. Finally, the HPLC method was validated and complied with ICH guidelines. This is the first report of detailed analysis of the chemical composition of Tiliae flos.
