Search results for "PHENOLS"
showing 10 items of 766 documents
Recovery of bioactive compounds from walnut (Juglans regiaL.) green husk by supercritical carbon dioxide extraction
2021
In this work, the use of supercritical carbon dioxide, a nontoxic solvent, was proposed to extract bioactive compounds from Juglans regia L. green husk and was compared to other traditional techniques based on solvents such as ethanol, methanol and water. Supercritical CO2 was combined with ethanol as an organic modifier at a rate of 20% of the total flow to achieve greater extraction of polar compounds. The extracts were characterised in terms of extraction yields, antioxidant activity, total polyphenol content, phenolic acids, juglone, volatile organic compounds and antifungal activity. The results showed that the extracts obtained with supercritical CO2 were rich in polyphenols (10750 mg…
A taxonomical study of the subtribe leontodontinae based on the distribution of phenolic compounds
1993
Abstract Evaluation of the phenolic constituents of five species belonging to the subtribe Leontodontinae (family Asteraceae) allowed the identification of ten flavonoid and eight phenolic acids by means of HPLC and other standard methods. The role of these compounds in relation to the morphological characteristics in the systematics of the subtribe is discussed.
Optimization of Polyphenols' Recovery from Purple Corn Cobs Assisted by Infrared Technology and Use of Extracted Anthocyanins as a Natural Colorant i…
2022
An ecofriendly extraction technology using infrared (IR) irradiation Ired-Irrad® was applied to purple corn cobs to enhance polyphenol recovery for the first time. The IR extraction efficiency was compared to that of the water bath (WB) method. Response surface methodology (RSM) using a central composite design was conducted to determine the effect of the experimental conditions (extraction time and treatment temperature) and their interactions on the total polyphenol and anthocyanin yields. Optimal extraction of total phenolic compounds (37 mg GAE/g DM) and total monomeric anthocyanins (14 mg C3G/g DM) were obtained at 63 °C for 77 min using IR as an extraction technique and water as a sol…
Capillary electrophoretic and nuclear magnetic resonance studies of interactions between halophenols and ionic liquid or tetraalkylammonium cations.
2003
Aqueous capillary electrophoretic studies were performed to investigate interactions between halophenols and 1-ethyl-3-methylimidazolium tetrafluoroborate or tetraethylammonium tetrafluoroborate electrolytes. In both cases, increased halogen size correlated with increased affinity for the electrolyte cation. For isomers, the ortho substituted isomer exhibited higher affinity than the para isomer. Irreproducible CE results for analyte pairs in the presence of the ionic liquid stimulated investigations of the interactions between halophenols as well as with the cations of the electrolyte. These interactions were explored by proton and fluorine one-dimensional NMR. The NMR results indicated di…
Modulation of intracellular calcium concentrations and T cell activation by prickly pear polyphenols.
2004
Opuntia ficus indica (prickly pear) polyphenolic compounds (OFPC) triggered an increase in [Ca2+]i in human Jurkat T-cell lines. Furthermore, OFPC-induced rise in [Ca2+]i was significantly curtailed in calcium-free buffer (0% Ca2+) as compared to that in 100% Ca2+ medium. Preincubation of cells with tyrphostin A9, an inhibitor of Ca2+ release-activated Ca2+ (CRAC) channels, significantly diminished the OFPC-induced sustained response on the increases in [Ca2+]i. Lanthanum and nifedipine, the respective inhibitors of voltage-dependent and L-type calcium channels, failed to curtail significantly the OFPC-induced calcium response. As OFPC still stimulated increases in [Ca2+]i in 0% Ca2+ medium…
Synthesis, mechanical and thermal rheological properties of new gellan gum derivatives
2017
New derivatives of gellan gum (GG) were prepared by covalent attachment of octadecylamine (C18- NH2) to polysaccharide backbone via amide linkage by using bis(4-nitrophenyl) carbonate (4-NPBC) as a coupling agent. The effect of the alkyl chain grafted onto hydrophilic backbone of high molecular weight GG was investigated in terms of physicochemical properties and ability of new derivatives to form hydrogels. A series of hydrogels was obtained in solutions with different kind and concentration of ions and their stability and mechanical properties were evaluated. The obtained derivatives resulted soluble at temperature lower than starting GG and physicochemical properties of obtained hydrogel…
Pharmaceutical properties of supramolecular assembly of co-loaded cardanol/triazole-halloysite systems
2015
Halloysite nanotubes were explored as drug carrier for cardanol, which is considered as a promising natural anticancer active species. To this aim, besides the pristine nanoclay, a chemical modification of the nanocarrier was performed by attaching triazolium salts with different hydrophobicity at the outer surface of the hollow nanotubes. The interaction between cardanol and nanotubes was highlighted in solution by HPLC. This method proved the loading of the drug into the nanotubes. The solid dried complexes formed by pristine and modified halloysite with the cardanol were characterized by IR spectroscopy, thermogravimetric analysis as well as water contact angle to evidence the structure,…
Assessment of the antioxidant and antibacterial activities of different olive processing wastewaters.
2017
Olive processing wastewaters (OPW), namely olive mill wastewater (OMW) and table-olive wastewaters (TOW) were evaluated for their antibacterial activity against five Gram-positive and two Gram-negative bacteria using the standard disc diffusion and thin layer chromatography (TLC)-bioautography assays. Disc diffusion screening and bioautography of OMW were compared to the phenolic extracts of table-olive brines. Positive activity against S. aureus was demonstrated. The optimization of chromatographic separation revealed that hexane/acetone in the ratio of 4:6 was the most effective for phenolic compounds separation. A HPLC-MS analysis was performed showing that only two compounds, hydroxytyr…
Chromatogrphic Profiles of Polyphenols and Terpenoids in the Herbs of Some Thymus L. Represntatives
2022
The aim of the work. To perform the identification of phenolic compounds and terpenoids in the aerial parts of Thymus pulegioides L. (cultivar ‘2/6-07’), Thymus richardii Pers. (cultivar 'Fantasy') and Thymus vulgaris L. (cultivar ‘Jalos’) using thin layer chromatography (TLC), as well as to conduct the gaschromatographic analysis of Thymus richardii essential oil. Materials and Methods. The TLC method was used in this study for the qualitative analyses of polyphenols and non-polar compounds in the aerial part of three Thyme (Thymus L.) species from the Lamiaceae Martinov family cultivated in Kherson region (Ukraine). The volatile compounds were determined in the essential oil of Thymus ric…
Effect of ultrasound pre-treatment and drying method on specialized metabolites of honeyberry fruits (Lonicera caerulea var. kamtschatica).
2019
Abstract Honeyberries are rich in various nutrients (eg. minerals, and vitamins) and bioactive compounds (eg. polyphenols). The aim of the study was to evaluate the impact of ultrasound (USN) pre-treatment (100% power at 37 kHz) at 40 °C for 3 min and drying techniques (conduction or vacuum) on nutritional composition and bioactive compounds of honeyberry fruits. The evaluation of dried barriers revealed that both USN pre-treatment and drying techniques affected the composition of the final product. The highest vitamin C content (1.067–1.187 mg 100 g−1 DM) was found in fruit samples pre-treated by USN, regardless of the drying technology used. The highest total phenol (2.445 mg GAE 100 g−1 …