Search results for "GALLIC ACID"
showing 10 items of 53 documents
Optimization of ultrasound-assisted extraction of phenolic compounds from grapefruit (Citrus paradisiMacf.) leaves via D-optimal design and artificia…
2018
The extraction of phenolic compounds from grapefruit leaves assisted by ultrasound-assisted extraction (UAE) was optimized using response surface methodology (RSM) by means of D-optimal experimental design and artificial neural network (ANN). For this purpose, five numerical factors were selected: ethanol concentration (0-50%), extraction time (15-60 min), extraction temperature (25-50 °C), solid:liquid ratio (50-100 g L-1 ) and calorimetric energy density of ultrasound (0.25-0.50 kW L-1 ), whereas ultrasound probe horn diameter (13 or 19 mm) was chosen as categorical factor.; Results: The optimized experimental conditions yielded by RSM were: 10.80% for ethanol concentration; 58.52 min for…
ORAC and TEAC assays comparison to measure the antioxidant capacity of food products
2009
Abstract Oxygen radical antioxidant capacity (ORAC) and trolox equivalent antioxidant capacity (TEAC) assays were compared to estimate the total antioxidant capacity (TAC) of orange juice, milk, and an orange juice-milk beverage. When the TEAC method was used with this beverage, an increase in the concentration of orange juice corresponded to an increase in TAC, but increasing the percentage of milk did not increase the TAC value. When the ORAC method was applied, it was seen that increased concentrations of juice or milk corresponded to greater antioxidant capacity. An evaluation was also made of the influence of certain compounds (ascorbic acid, gallic acid, β-carotene, lutein, zeaxanthin…
Effects of polyphenols and lipids from Pennisetum glaucum grains on T-cell activation: modulation of Ca2+ and ERK1/ERK2 signaling
2015
International audience; BACKGROUND: Pearl millet (PM), i.e., Pennisetum glaucum, is widely grown in Africa and known for its anti-oxidant and anti-hyperlipidemic properties.METHODS: The P. glaucum grains were obtained from the region of Ouled Aïssa (South of Algeria). We assessed the effects of phenolic compounds and lipids, extracted from seeds of P. glaucum, on rat lymphocyte proliferation, activated by phorbol 12-myristate 13-acetate and ionomycin. In order to explore signaling pathway, triggered by these compounds, we assessed interleukin-2 (IL-2) mRNA expression and extracellular signal-regulated kinase-1/2 (ERK1/ERK2) phosphorylation. Finally, we determined increases in free intracell…
Synthesis and Biological Evaluation of Combretastatin A-4 and Three Combretastatin-Based Hybrids
2012
The syntheses of combretastatin A-4 from gallic acid and of three combretastatin-based hybrids are described. Starting from commercial gallic acid, the phosphonium salt (3,4,5-trimethoxybenzylphosphonium bromide) is synthesized and coupled, through a Wittig reaction, with several aldehydes, including methoxymethyl-protected isovanillin, the aldehyde γ-bicyclohomofarnesal having a labdane skeleton, 3-(3-pyridyl) propanal, and furfural. The biological properties of the cis-coupled compounds as cytotoxic, antiviral and antifungal agents are also reported. In addition, pyrogallol, gallic and 3,4,5-trimethoxybenzoic acids have been studied biologically.
Phytochemical characterization and biological activities of green tea (Camellia sinensis) produced in the Azores, Portugal
2021
Abstract Background Green tea is not only one of the most widely consumed beverages worldwide, but is also known for its health promoting and therapeutic effects. Green tea is cultivated in areas with high humidity and acidic soils in China, Indonesia and Japan. Those places have well-marked dry and rainy seasons. In opposite, Azores have a climate with constant average annual rainfall and, unlike eastern regions, relatively constant air humidity throughout the year. While a brand implemented on the Portuguese market, the quality of green tea produced in Azores must be guaranteed. Quality control measures based on phytochemical determination of the chemical composition and biological activi…
Tannins from Hamamelis virginiana Bark Extract: Characterization and Improvement of the Antiviral Efficacy against Influenza A Virus and Human Papill…
2014
Antiviral activity has been demonstrated for different tannin-rich plant extracts. Since tannins of different classes and molecular weights are often found together in plant extracts and may differ in their antiviral activity, we have compared the effect against influenza A virus (IAV) of Hamamelis virginiana L. bark extract, fractions enriched in tannins of different molecular weights and individual tannins of defined structures, including pseudotannins. We demonstrate antiviral activity of the bark extract against different IAV strains, including the recently emerged H7N9, and show for the first time that a tannin-rich extract inhibits human papillomavirus (HPV) type 16 infection. As the …
Clonal differences in growth and phenolics of willows exposed to elevated ultraviolet-B radiation
2003
Abstract In this study, the effects of elevated ultraviolet-B (UV-B, 280–320 nm) radiation on growth and leaf phenolics were evaluated in clones of dark-leaved willow ( Salix myrsinifolia Salisb.) and tea-leaved willow ( Salix phylicifolia L.). Willows were raised for one growing season in an irradiation field, where they were exposed either to a constant 50% increase in UV-B CIE radiation simulating 20–25% ozone depletion or to a small increase in UV-A radiation (320–400 nm). Control willows were grown in the irradiation field under solar radiation (ambient control). Despite the high constitutive concentrations of a UV-absorbing leaf flavonoid, dihydromyricetin, UV-treatments clearly reduc…
COLORECTAL CANCER AND INFLAMMATORY BOWEL DISEASES: EFFECTS ON DIET AND ANTIOXIDANTS
2017
It is well established that oxidative stress is common in inflammatory bowel diseases (IBDs). Accordingly, antioxidants are recommended for treatment. The aim of this study is to compare the effects of antioxidants contained in the various types of tea on symptoms and evolution of IBD and colorectal cancer (CRC). Analysis of the literature revealed that the theaflavin-3, 30-digallate (TFDG) contained in black tea, and epigallocatechin-3-O-gallate (EGCG) contained in green tea have protective effects against oxidative stress. Moreover, these substances are involved in many biochemical processes responsible for inflammation and proliferation of cancer cells. It is documented that both TFDG an…
Intracellular compartmentation and regulation of two shikimate dehydrogenase isoenzymes in Pisum sativum
1974
Summary Pea seeds as well as sprouts and roots contain two isoenzymes of shikimate dehydrogenase. Both isoenzymes can be separated by Polyacrylamide gel electrophoresis as well as through ammonium sulfate fractionation. The molecular weight of both isoenzymes are the same although the net electric charge is different. The Km value for isoenzyme 1 is 3,5 × 10 −4 and the Km value for isoenzyme 2 is 1,67 × 10 −4 M. 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid, anthranilic acid and p-methoxycinnamic acid inhibited both isoenzymes competitively. Anthranlic acid showed the largest affinity to both isoenzymes. M-methoxycinnamic acid and m-nitrocinnamic acid inhibited both isoe…
Influence of Temperature, Solvent and pH on the Selective Extraction of Phenolic Compounds from Tiger Nuts by-Products: Triple-TOF-LC-MS-MS Character…
2019
The aim of this study was to assess the effect of temperature, solvent (hydroethanolic mixtures) and pH on the recovery of individual phenolic compounds from &ldquo